In a first step, slot synchronization may be obtained by setting in correlation the received signal with a primary sequence, which represents the primary channel, and storing the received signal. During a second step, the correlator may be re-used for correlating the received signal with a secondary sequence corresponding to the secondary synchronization codes. The correlator may include a first filter and a second filter connected in series, which receive a first secondary sequence and a second secondary sequence, which may include Golay sequences. Architectures of parallel and serial types, as well as architectures designed for reusing further circuit parts are also disclosed. The invention is particularly applicable in mobile communication systems based upon standards such as UMTS, CDMA2000, IS95, and WBCDMA.

To enable acquisition of a base station by a mobile terminal included in a telecommunications system based upon the standard 3GPP FDD mode, TDD mode, etc., the corresponding receiver needs to perform frame synchronization and identification of the so-called codegroup. These functions are important for the execution of the subsequent steps of the cell search system.
In particular, when a mobile terminal is turned on, it does not have any knowledge of the timing of the transmitting cell to which it is to be assigned. The 3GPP standard proposes an initial cell search procedure for acquiring the cell signal and synchronizing therewith. This synchronization procedure basically includes three steps: (1) slot synchronization; (2) frame synchronization and identification of the codegroup, i.e., the group of cell codes; and (3) identification of the scrambling code.
In the implementation of the second step, it is assumed that the slot synchronization has previously been obtained during the first step. At this point, to obtain the frame synchronization and identify the codegroup (to which the offset of the cell is associated), in the second step the Secondary Synchronization Channel (SSCH) is used. More particularly, codes or words of 256 chips (i.e., letters) are transmitted at the beginning of each slot.
The sixteen 256-chip complex codes used by the standard are generated as follows. A first sequence at chip rate b having a repetition period of 16 (i.e., repeating every 16 elements) is multiplied by a sequence·16 times slower according to the following two formulas to obtain the base sequence z, where:z=<b, b, b, −b, b, b, −b, −b, b, −b, b, −b, −b, −b, −b, −b>; andb=<1, 1, 1, 1, 1, 1, −1, −1, −1, 1, −1, 1, −1, 1, 1, −1>.
The base sequence z is then multiplied element by element by a Hadamard code of length 256 chosen according to the following rule. If m is the number identifying the Secondary Synchronization Code (SSC) to be generated, the number of the Hadamard code to be multiplied by the sequence z is equal to 16×(m−1), with m ranging from 1 to 16. Generation of the synchronization codes SSC for the TDD mode is similar to the one used for the FDD mode, with the difference being that, in the former case, just twelve of the sixteen codes SSC are used.
Moreover, the FDD mode and TDD mode differ from one another with respect to the way in which the codegroups are associated with the contents of the secondary synchronization channel SSCH. In the FDD mode, on the secondary synchronization channel SSCH a code SSC is sent for each slot, in 15 consecutive slots. There are 64 possible sequences indicated by the standard, which belong to a Reed-Solomon code defined therein. Each sequence identifies a group of eight primary scrambling codes, among which the aforementioned third step of the cell search procedure will identify the code of the cell onto which the first two steps of the procedure have locked.
In the TDD mode, each slot containing the channel SCCH contains three codes SSC. According to the standard, four possible sets of three codes are defined, the combination and the relative phases of which define the codegroups. Each codegroup identifies one slot offset between the start of the slot and the start of the code on the channel SSCH, and four possible basic midambles to each of which is associated a scrambling code. The third step of the cell search procedure defines which midamble is used in the Primary Common-Control Physical Channel (P-CCPCH).
Referring to FIG. 1, a schematic representation of an architecture of a known prior art circuit which implements the first step and second step of the cell search procedure is now described. The received signal r is sent in parallel to a first branch 411, which implements the first step of the cell search procedure, and to a second branch 412, which implements the second step of the cell search procedure. Both the circuits of the first branch 411 and the circuits of the second branch 412 operate under the control of a controller, designated by 403, which receives the results of their processing operations.
The first branch 411 includes a matched filter 401 for carrying out the correlation on the Primary Synchronization Channel (PSC), setting the channel in correlation with a sequence SG structured as a first hierarchical Golay sequence. A subsequent block 402 implements the algorithm of the first step of the cell search procedure. The use of Golay sequences to carry out synchronization functions in systems of a spread-spectrum and CDMA type is described, for example, in WO-A-0051392, WO-A-0054424, WO-A-0067404 and WO-A-0067405.
The second branch 412 instead includes a correlation section 404, which operates on the secondary codes SSC. The correlation section 404 is followed by a block 405 which implements the algorithm of the second step of the cell search procedure. Operation of the correlation section 404 is enabled by an appropriate enabling signal EN issued by the controller 403.
Since the circuits that implement the second step of the cell search procedure for the FDD mode identify the individual chip, they are of the type illustrated schematically in FIG. 2, which are described in European patent application EP02425619.0, which is assigned to the Assignee of the present application. These circuits include, at the input, a correlation section including a bank of correlators 10, the outputs of which supply the energies corresponding to the individual chips.
After a possible masking with appropriate weights at block 12, the energies are added in a node 14 and are then stored in a bank of registers 16. Each row of registers 16 represents one of the words of the code that is to be recognized, while the columns represent the possible frame starting points in terms of slots, i.e., 15 possible starting points. A block 18 includes a comparator which enables the search for the maximum value to be carried out on the bank 16. The reason for this is to define both the codegroup CD used by the cell being currently evaluated, and the start of the frame expressed as frame offset OF transmitted by the cell itself. In other words, the frame offset OF is a quantity identifying the frame synchronization with reference to the slot timing obtained in the first step, which is not specifically shown for clarity of illustration.
Accordingly, the circuit illustrated in FIG. 2 essentially uses a bank of correlators in parallel or, alternatively, a bank which performs the fast Hadamard transform, for carrying out correlation. As note above, in the TDD mode the second step of the cell search procedure is instead carried out assuming that the position of the synchronization burst, as well as a first slot synchronization, have been acquired and defined in the first step of the cell search procedure. This is done to obtain the following: slot synchronization, by defining the offset between the start of the slot and the position of the synchronization burst therein; codegroup identification; and further information, such as the cell parameter.
To do so, the secondary synchronization channel SSCH is used. In the synchronization slot and simultaneously on the channel PSC are transmitted three 256-chip codes coming from of a set of twelve complex codes, which represents a subset of the secondary synchronization codes SSC used in the FDD mode. To extract all the requisite information from the channel SSCH, it is necessary to correlate the received signal with the possible codes transmitted on the channel SSCH. Of these codes, it is also necessary to identify the set of three codes with the highest correlation energy and to use their phases to define, in accordance with the standard, the corresponding parameters of slot offset (i.e., the distance in time between the start of the slot and the start of the synchronization code), codegroup, and frame number (even or odd frame).
The above operation is carried out by a circuit that includes correlation section including twelve matched filters arranged in parallel. This approach is schematically illustrated in the diagram of FIG. 3, where a bank 20 of twelve complex finite impulse response (FIR) filters, which are coupled to the twelve possible secondary synchronization codes SSC. The samples of the received signal r are sent at the input to the bank 20 of FIR filters. On the twelve outputs of the bank 20, signals indicating the correlation energies corresponding to the codes SSC are generated. These signals are sent to a system 21, for detecting the maximum value.
The system 21 for detecting the maximum value identifies a given number (equal to three) of codes SSC having the highest correlation energy. These codes are sent to a comparison block designated by 22. The block 22 compares the codes with vales in a table. More particularly, the table stores, according to the possible combinations of the phase differences of the set of three codes SSC identified, corresponding codegroups CD, slot offsets OS, and frame numbers FN, which are then supplied at the output by the comparison block 22.
An alternate architecture for implementing the second step of the cell search procedure in the TDD mode is shown in FIG. 4, which is described in detail in Italian patent application T02002A001082, also assigned to the present Assignee. Here, the received signal r is sent at the input to a block 110, which carries out a first correlation operation on a first sequence 16 chips long. The received signal r at output from block 110 is sent to a bank of correlators 111, which forms the correlation section. The samples of the received signal r are also stored in a storage unit 112.
The correlator bank 111 includes only four correlator circuits, one for each code set. The bank 111 receives four "first" codes SSC from a system 113 for generating codes, each one of which belongs to and identifies one of the four possible code sets within the set of codes SSC. There are twelve codes SSC in all, and each code set corresponds to a "first" code identifying the set, and a subset of remaining codes corresponds to the other two codes of the set. The correlation operation performed in block 111 is hence able to supply, at its output, an estimate of the code set received.
In this connection, a block 114 carries out a search for the maximum value received from the correlator bank 111 on the energies corresponding to the first four codes SSC supplied by the system. It also supplies at its output a first code SSC having the best correlation energy, and with the corresponding phase offset. In this way, a code set CS to which the first code SSC belongs is identified.
The first code SSC and its phase offset are to be sent on to a comparison block 115, while the information on the code set is sent to a controller designated by 116. The controller 116 presides over operation of the circuit and, in particular, is designed to supply the code-generation system 113 with the information on the "first" four codes SSC to be generated for identifying the four code sets.
Based upon the first code and the corresponding code set CS identified by the search for the maximum value carried out in the block 114, the controller 116 sends to the code-generation system 113 the information regarding which other codes SSC are to be generated for the correlation operation with the received signal r stored in the storage unit 112. The above other codes are simply the remaining two codes SSC in the subset that completes the code set corresponding to the first code selected by the search carried out by block 114.
Upstream of the bank 111, a multiplexer 120 is provided, which is driven by the controller 116 and selects the output of the block 110 or the output of the storage unit 112 for the bank 111. In this way, the received signal r, in addition to being stored in the unit 112, is initially sent directly to the block 111, where it is correlated with the first four codes that identify the four code sets coming from block 113. Subsequently, once the reference code set has been identified (as a result of the search carried out in the unit 114), the samples of the received signal r stored in the unit 112 can be sent to the block 111 to be correlated with the two remaining codes of the aforesaid code set. The correlator bank 111 is equipped with a correlator memory 121, in which the first code SSC of the detected code set is stored.
Based upon the information regarding the selected code set CS, the controller 116 issues a command to the code-generation system 113. This is done so that the latter will generate the two codes corresponding to the two codes that are missing for composing the set of three codes of the code set CS to make a correlation with the samples of the received signal r stored in the storage unit 112. The result of this correlation operation (which is carried out, so to speak, by "recycling" two of the correlators contained in the bank 111) is also supplied to the block 115, where the set of three codes of the code set CS is recomposed. This set of three codes can be used, together with the corresponding phases, for the comparison with the standard tables to extract the corresponding parameters from the table contained in the comparison block 115.
The prior art approaches illustrated in FIGS. 1-4 thus require allocation of a certain amount of memory and, consequently, of area on the chip. As such, a consequent power consumption for implementing the correlation section for the second step of the cell search procedure results.

Process and device for synchronization and codegroup identification in cellular communication systems and computer program therefor


A shielded connector assembly (10) includes a header (20), a shield plate (30), and a pin guide (40). The shield plate (30) is formed of a metallic material and is mounted to header (20) by action of clips (34a) which engage clip engaging surfaces (24a) of header (20). Pin guide (40) is mounted to header (20) by action of dovetailed sections (46) which are slidingly disposed in respective dovetailed recesses (26) formed in header (20).

Shielded electrical connectors are used in the electronics industry for their ability to shield electrical circuits from the deleterious effects of ambient electrical or electromagnetic energy, i.e. EMI. A standard shield design provides a ground path whereby the electromagnetic energy is drained to ground and is thereby dissipated. Shielded connectors often include pin contacts as a means of electrically connecting the connector to, for example, a printed circuit board. For manufacturing reliability, the pins are protected and guided to specific soldering locations on the printed circuit board by a pin guide member. Assuming that the reliability of the finished shielded connector product is satisfactory, the cost of production of such electrical connectors is often the determining factor as to whether the product will be commercially successful. Therefore, in general, the combination of high reliability of the shielded connector with the low overall cost thereof is most advantageous.
A known shielded connector assembly is disclosed in U.S. Pat. No. 5,304,069, hereby incorporated by reference in its entirety, which assembly provides a shielded connector housing with a pin guide member. A board lock is integrally formed with the shield, and the pin guide member is mounted to the connector by gussets which extend from a rear face of the connector. The unitary shield/board lock construction is expensive to manufacture, and presents potential manufacturing and assembly difficulties as well. Moreover, largely due to the gusset structure, the known connector would disadvantageously use a copious amount of space in an electronics package.


The present invention provides an apparatus and associated method of detecting pattern unevenness in the surface of an object. The apparatus includes a light source for irradiating surfaces of an object and a line sensor camera for detecting unevenness in the surfaces. The method comprises the steps of irradiating a light onto a surface having a pattern formed on the surface thereof, and observing the scattered light from the pattern edge portions, thereby inspecting pattern unevenness by way of the line sensor camera.

The present invention relates to a method and an apparatus for detecting surface pattern unevenness generally by the use of a line sensor camera. More particularly, the invention relates to surface pattern unevenness detecting method and apparatus which permit effective use in the manufacture of a liquid crystal display panel (liquid crystal TFT substrate) or a polysilicon TFT substrate.
When manufacturing a liquid crystal display panel (liquid crystal TFT substrate), for example, it is necessary to apply a photolithographic process comprising the steps of exposing a substrate comprising a glass support, a metal (Cr) layer and a resist layer to a prescribed image by means of an exposure unit, and then, developing the thus exposed resist layer, thereby preparing a prescribed resist pattern.
At this point, a visual inspection is carried out by the use of a wide light source to check whether or not operation of the exposure unit is normal. One of the particularly important inspection items is the inspection of exposure unevenness on the resist layer caused by an abnormal focusing of the exposure unit. In the conventional art, it is difficult to automatically obtain an observation image of the resist pattern on the substrate surface. It is therefore the conventional practice to determine the extent of exposure unevenness by irradiating a monochromatic light source on the substrate and visually watching the reflected light from the resist edge of the resist pattern. According to this practice, however, the functional inspection by manual operation results in considerable dispersions, and further, the recent tendency of TFT substrates toward a larger size is making it difficult to carry out a visual inspection. There is therefore an increasing demand for automation of the exposure unevenness inspection.
Under the circumstances as described above, it is known to obtain an image on a substrate 1 which is a stationary object of inspection by means of a two-dimensional CCD sensor camera 10 as shown in FIG. 1. In this configuration, an image is obtained by means of the two-dimensional CCD sensor camera 10 arranged diagonally above an end of the substrate 1 by irradiating a light from a light source 20 from diagonally above the other end of the substrate 1 having a resist pattern on the surface thereof via a Fresnel lens 21 and a white scattering plate 22 onto the substrate 1.
However, because this configuration permits observation of exposure unevenness only within a tight angular range, while satisfactory observation is possible for the center portion of the substrate image 1G substantially corresponding to the center portion of the monitor 100, sufficient focusing is unavailable at top and bottom end portions. For a larger-sized substrate 1 to be inspected, therefore, it becomes impossible to observe unevenness throughout the entire surface of the substrate 1.
In order to obtain satisfactory focusing for the entire screen, a conceivable way is to include the image forming plane of a sensor camera 10 having a lens system 11 and a sensor 12 by an angle (.alpha.) in a direction in which the light receiving plane of the sensor 12 leaves the substrate 1 to be inspected, as shown in FIG. 2. This measure is not however acceptable because distortion at top and bottom of the screen of the monitor 100 becomes larger, as shown in FIG. 3.

Surface pattern unevenness detecting method and apparatus


This invention relates to a pneumatic power cylinder dashpot piston which formed of an elastomeric cylinder and a sleeve and having a space between the interior wall of the cylinder and the exterior wall of the sleeve, and the space is filled with a fluid. The piston is connected to a power shaft of a power cylinder. The sleeve is corrugated and is formed integrally with the cylinder so as to prevent the escape of the fluid through a joint. The interior cylinder wall is tapered from the center thereof in opposite directions so that the cylinder, engaged by a disk on the power shaft, gradually comes into contact with an end portion of the cylinder whereby the corrugations of the sleeve are compressed at one end and the other corrugations are straightened.

(1) Field of the Invention
This invention relates to an improved dashpot system and more particularly to a dashpot for a power cylinder.
(2) Description of the Prior Art
Existing power cylinders have dashpots at the end of their power strokes. A dashpot is a device used to cushion or dampen a movement in a power cylinder and consists essentially of a power cylinder containing a gas or a liquid fluid and a piston moving in the assembly. The end of the power cylinder is configured to contain a centered cup with a tapered inside diameter and the piston is configured to include a centrally oriented cone extending from each side of the piston. The end of the power stroke will be such that the cone will enter the cup and displace the fluid contained therein. However, as the cone penetrates the tapered cup, the radial clearance between the cup and the cone will narrow. As a result, due to the decreased clearance, an increasingly greater resistance to fluid flow develops. This results in a higher pressure being developed in the cup which eventually stops the piston. The pressure results in a higher and higher force being developed and acting on the cone and, thus, on the piston, to decelerate the piston from the direction in which it is moving. In the perfect system, the decelerating counter action of the cup and cone on the piston is of such a force so as to stop the piston. The momentum of the system has, therefore, been counterbalanced and the piston stops without any end position shock.
This arrangement works fine when it is operated with a relatively incompressible fluid, such as an oil. However, when the fluid is a gas, such as air, it will not work because the air compresses. One reason for this is that if the supply for an incompressible fluid is shut off, pressure in the power cylinder drops very rapidly. However, if the supply is shut off for a compressible fluid, then the gas which is already in the power cylinder will simply expand and continue to exert force on the system's piston. In addition, it is necessary to closely control the clearance between the cup and cone in a pneumatic dashpot or insufficient pressure will be built up in the cup to properly decelerate the piston. These close tolerances introduce the risk of the cup and cone having a mechanical impact upon the system reaching the end of the stroke. Further, even if the mechanical components are aligned and are machined perfectly, the trapped air is compressible and therefore does not develop a significant counter-balancing force until a significant portion of dashpot travel has occurred. As a result of the air's compressibility, it is necessary to make pneumatic dashpots lengthy. The combination of the requirements for precise machining, rigid alignment, and a lengthy dashpot results in expensive dashpots which are very susceptible to malfunction due to wear, dirt particles in a system or the like.
Past consideration has been given to combining the benefits of a hydraulic dashpot in a pneumatic power cylinder. However, designing a hydraulic dashpot and incorporating it into caps of a pneumatic power cylinder would be accomplished at considerable risk as such operation would be dependent upon proper alignment of a seal located between the dashpot actuating rod which would be necessary in order to separate the pneumatics from the hydraulics. While leakage of oil into the pneumatic system could cause autoignition, leakage of air into the oil dashpot would destroy the effectiveness of the dashpot. Another alternative is to design a slave hydraulic cylinder which can be connected in parallel to a working pneumatic cylinder. This may eliminate the chance of the hydraulics and pneumatics mixing, but would be accomplished at considerable cost and space.
A search has been conducted of the United States Patent Office records and certain patents have been cited as further illustrative of the art. These patents are: Ban et al., entitled "Piston Unit", U.S. Pat. No. 4,342,884; Hasche et al., entitled "Valve Control Mechanism", U.S. Pat. No. 2,737,970; Williams, entitled "Rod Operated Valve", U.S. Pat. No. 4,359,204; Whittaker et al., entitled "Valve Assembly", U.S. Pat. No. 3,286,465; and Fornasari, entitled "Four-Way Electrovalve Governed By A Thermoactuator Associated With A Thermistor (PTC)", U.S. Pat. No. 4,753,271.

The United States of America as represented by the Secretary of the Navy


A method for applying an algorithm to facilitate the design of wideband omnidirectional antennas, and the design of sleeve cage monopole and sleeve helix units includes rapid resolution of a complex relationship among antenna components to yield an optimal system. A genetic algorithm is used with fitness values for design factors expressed in terms to yield optimum combinations. Cage antennas are optimized via a genetic algorithm for operation over a wide band with low VSWR. Genetic algorithms and an integral equation solver are employed to determine the position and lengths of parasitic wires around a cage antenna in order to minimize VSWR over a band. The cage may be replaced by a normal mode quadrifilar helix for height reduction and with re-optimized parasites.

Recent advances in modern mobile communication systems, especially those which employ spread-spectrum techniques such as frequency hopping, require antennas which have omnidirectional radiation characteristics, are of low profile, and can be operated over a very wide frequency range. The simple whip and the helical antenna operating in its normal mode appear to be attractive for this application because they naturally have omnidirectional characteristics and are mechanically simple. However, these structures are inherently narrow band and fall short of needs in this regard. Hence, additional investigations must be undertaken to develop methods to meet the wide bandwidth requirement of the communication systems.

Designs for wide band antennas with parasitic elements and a method to optimize their design using a genetic algorithm and fast integral equation technique


A forged product is made of a magnesium alloy and includes a through hole making portion to make a through hole that runs in a predetermined direction, and a bottom portion that lies on a plane intersecting with the predetermined direction. The through hole includes a first portion that has been formed by a forging process and a second portion that has been formed after the forging process. The second portion of the through hole has shifted toward the bottom portion with respect to the middle of the through hole in the predetermined direction.

1. Field of the Invention
The present invention relates to a forged product and a method of making such a product.
2. Description of the Related Art
An upper bracket, an under bracket and other supporting members are used as members for fixing the handlebars and front fork of a motorcycle. An example of upper and under brackets (which will be collectively referred to herein as "handlebar supporting members") is shown in FIGS. 8 and 9.
As shown in FIGS. 8 and 9, each of the upper bracket 700 and under bracket 800 includes bosses 2a, 2b and 2c. The bosses 2a and 2b at both ends have through holes 1a and 1b, into which a front fork 30 is inserted. Although the front fork 30 shown in FIG. 9 is inserted into just one of the two through holes 1a and 1b, the front fork 30 is actually inserted into the other through hole 1b as well. Meanwhile, the boss 2c at the center has a through hole 1c, into which a steering shaft 40 is inserted. The rider can turn the front wheel to any direction he or she likes with the handlebars since the front fork 30 and the steering shaft 40 are supported by the upper bracket 700 and the under bracket 800.
To increase the fuel consumption and cut down the exhaust gas, a lot of people think it is important to reduce the overall weight of a motorcycle as much as possible. For that purpose, in the prior art, the upper bracket, under bracket and other handlebar supporting members are made of an aluminum alloy, which has a lighter specific gravity than steel. A handlebar supporting member made of an aluminum alloy is usually formed by subjecting a cast product, which has been formed by a casting process such as die casting, to a T6 heat treatment (including a solution treatment and an artificial aging treatment) in order to increase its mechanical strength.
Meanwhile, methods of making a magnesium alloy, which has an even lighter specific gravity than an aluminum alloy, have been developed. Also, techniques for increasing the strength and machinability of a magnesium alloy have been developed, too. That is why the handlebar supporting members are now preferably made of a magnesium alloy, not an aluminum alloy. The specific gravity of a magnesium alloy is approximately two-thirds of that of an aluminum alloy. For that reason, the weight of a motorcycle can be further reduced by using a magnesium alloy.
If a magnesium alloy is used, however, it is difficult to achieve a sufficient mechanical strength just by subjecting the cast product to a heat treatment. Thus, Japanese Patent Application Laid-Open Publication No. 6-172949 proposes that after a cast product made of a magnesium alloy has been forged, the forged product be subjected to a T6 heat treatment. On the other hand, Japanese Patent Application Laid-Open Publication No. 2002-254132 proposes that after a billet of a magnesium alloy that has been formed by a continuous casting process is subjected to a hot extrusion process, the billet be treated by a solution treatment, a forging process and then an aging treatment in this order. According to any of these techniques disclosed in Japanese Patent Application Laid-Open Publication Nos. 6-172949 and 2002-254132, the mechanical strength can be increased sufficiently by a plastic deformation to be caused by a forging process on the workpiece.
However, the present inventors discovered and confirmed via experiments that when the technique including the forging process as disclosed in Japanese Patent Application Laid-Open Publication Nos. 6-172949 and 2002-254132 was simply applied to making a handlebar supporting member, the workpiece would experience unexpected deformation (or would be bent) at an early stage of the forging process.
If such a deformation were produced in the workpiece, the workpiece would be deformed plastically so much that an increased press tonnage should be applied to get the forging process done and the die would have decreased durability as a result. Also, if such a deformation were produced, the workpiece might sometimes chip (that is, have a shape defect, e.g., an underfill) at the edges. Such chipping could be avoided by subjecting a workpiece that has been formed in a bigger size to a forging process. In that case, as the workpiece has a bigger size than required, an increased amount of burr will be left after the forging process, thus decreasing the yield (also referred to as the "material utilization factor") of the material. On top of that, since a magnesium alloy is much more expensive than an aluminum alloy, such a decrease in material yield would increase the overall manufacturing cost significantly.
One reason why the workpiece has such a deformation is that the through hole of the handlebar supporting member has a portion to be formed by the forging process and another portion to be formed after the forging process. If the handlebar supporting member is made by a method including the forging process, the through hole of the handlebar supporting member is made by making a non-through hole once in a workpiece by the forging process and then removing a bottom portion of the non-through hole by a machining process, for example.

Forged product and method of making the product


One embodiment of the present invention provides a system that facilitates code verification and garbage collection in a platform-independent virtual machine. The system operates by first receiving a code module written in a platform-independent language. Next, the system examines the code module to locate calls to program methods within the code module. The system then transforms the code module so that all operands remaining on the evaluation stack only relate to the called method when the method is called, thereby simplifying verification and garbage collection of the code module.

1. Field of the Invention
The present invention relates to the design of platform-independent virtual machines. More specifically, the present invention relates to a method and an apparatus to facilitate code verification and garbage collection in a platform-independent virtual machine.
2. Related Art
Dramatic advances in computer technology presently make it possible to integrate a significant amount of computing power onto "smart cards." Smart cards are presently used in a variety of applications that solve common security and identity needs. For example, smart cards have been integrated into credit cards, debit cards, corporate badges, and even cell phones.
New smart card designs can accommodate larger amounts of memory. For example, new smart card designs can accommodate up to 160K bytes of read-only memory (ROM), 64 K bytes of electrically erasable programmable read-only memory (EEPROM), and 8 K bytes of random access memory (RAM). These larger amounts of memory make it possible to integrate more functionality into a smart card.
In particular, the additional memory can be used to implement a virtual machine, such as the JAVA™ virtual machine (JVM), in a smart card, and to allow the use of objects defined within an object-oriented programming system. (JAVA is a trademark of SUN Microsystems, Inc. of Santa Clara, Calif.) Integrating a virtual machine into a smart card enables the smart card to execute a large number of platform-independent applications. Moreover, the associated development environment for the virtual machine can simplify the process of developing applications for smart cards.
While it is possible to implement a virtual machine on one of these smart cards, the memory is still quite limited compared to a typical desktop computer system. This limited memory leads to many challenges in the implementing a virtual machine.
One problem is that programming languages, such as JAVA and corresponding JAVA bytecodes, are often unnecessarily complicated, which leads to unnecessary complexity in the virtual machine. In particular, the JAVA programming language (and corresponding JAVA bytecodes) can leave data on the stack during a call to a method. This data can cause difficulties during code verification and garbage collection because this data is left between activation records where it complicates the garbage collection and verification processes. For example, in the Connected Limited Device Configuration (CLDC) version of Java, bytecodes include a typemap for each basic block within the method. A typemap provides a map of local variable and stack types in a method. Having multiple typemaps per method unnecessarily complicates garbage collection because the garbage collector needs to access each of these typemaps during garbage collection. Additionally, variables can hold different types of data at different times. A variable in one instance can be a pointer and the same variable at another time can be a primitive data type, such as an integer or float. This causes difficulties for the garbage collector and verifier because they have to determine the type of a variable before completing their functions.
Hence, what is needed is a method and an apparatus that facilitates code verification and garbage collection in a platform-independent virtual machine without the problems described above.

Method and apparatus to facilitate code verification and garbage collection in a platform-independent virtual machine


The present invention comprises a reconfigurable variable voltage battery. One or more variable voltage battery (VVB) modules are connected in series to form a stacked variable voltage battery (SVVB or Stacked VVB). A variable voltage battery module may comprise at least one battery cell and processor controlled switches adapted to vary the output of the variable voltage battery module. By separately configuring the switches of each VVB module, the output of the stacked VVB module can produce any voltage up to the full sum of the voltages of all the cells in the individual VVB modules. In addition, charge balancing can easily be achieved with a stacked VVB configuration, as some VVB modules can be bypassed (e.g., by setting select switches to simulate a short condition) either to prioritize the discharging of stronger VVB modules, or to prioritize the charging of weaker VVB modules.

The present invention relates to the field of reconfigurable variable voltage electric batteries designed for use with inverters, energy storage systems, uninterruptable power supplies, and the like, including variable voltage batteries for use in the drive systems of electric vehicles such as bicycles, automobiles, trucks, locomotives, utility carts, and the like.
This application is an improvement to and an extension of commonly owned U.S. Pat. No. 8,816,613, which issued on Aug. 26, 2014, entitled Reconfigurable Battery (hereinafter referred to as "Reconfigurable Battery Patent"), the entire contents of which is incorporated herein by reference for all purposes.
It should be noted that a practical system such as an electric vehicle involves two distinct operations, one that drives the motor and the corresponding drive wheel(s) by supplying current from the battery to the motor(s), and another that uses the current from the motor(s) to charge the battery to achieve regenerative braking, thereby slowing down the vehicle. It should be further apparent to those skilled in the art that in order to recharge the battery, one needs an inverter that increases the voltage from the motor to a value higher than the battery voltage, in order for the current to flow back into the battery.
For a typical rechargeable battery, the charging voltage must be higher than the battery voltage. The higher the charging voltage relative to the battery voltage, the more current flows into the battery. Controlling the charging voltage is one of the ways to control the rate of recharging, as well as the rate of braking. Another way to control the recharging rate is pulse width modulation (PWM), where a switch between the charging source and the battery regulates an on-off duty cycle. Of course, the charging voltage still needs to be higher than the battery voltage for such a device to work.
In most electric vehicles such as electric bicycles and electric cars that utilize regenerative braking, the electrical system typically consists of several subsystems, namely a motor, a speed controller, an inverter, and a battery. Sometimes the speed controller regulates both the drive and braking current via PWM. Potentially, a clever inverter design could regulate both driving and braking by regulating the voltage to the motor for driving, and regulating the voltage to the battery for regenerative braking, thereby eliminating the need for a separate speed controller.
However, an inverter is not an easy device to design or cheaply produce, as it must handle a large amount of current (especially during quick braking) and sometimes a high output voltage, while its input voltage can fluctuate over a wide range. The input voltage in this case is the back EMF from the motor, typically close to zero when the vehicle is coming to a stop, and close to the maximum battery voltage when the vehicle is coasting on a level ground at its maximum speed (usually the battery voltage limits the top speed).
Also, an inverter typically achieves its functionality using rapid switching devices. One inverter design could turn the DC current from the motor to AC current first, increase the voltage using a step-up transformer, and convert the AC current back to DC in order to recharge the battery. Another inverter design could use temporary energy storage elements such as capacitors and inductors in a charge-pump configuration in order to raise the voltage. The switching frequency involved is typically in the order of 1-100 KHz. In most of the known inverter designs, the energy loss is significant, and the cost is very high due to the high current requirement (100 Amps or more) in addition to the weight.
The Reconfigurable Battery Patent discloses a battery and/or electric motor configuration that provides driving and regenerative braking, for example in an electric vehicle, over a reasonable range of operations without the need for an inverter. The Reconfigurable Battery Patent also discloses a reconfigurable battery and battery control system that provides duty cycle modulation of an array of battery cells for intermediate output voltage control without incurring large switching losses, while simultaneously reducing switching induced transient signals.
It would be advantageous to extend the concepts set forth in the Reconfigurable Battery Patent to provide greater configurability, greater scalability and modularization, increased efficiency, and improved charge balancing, all at reduced costs.
The methods and apparatus of the present invention provide a series connected stack of reconfigurable variable voltage battery modules having these and other advantages.

Stacked variable voltage battery module arrangement


An information processing apparatus includes a control unit (140) that executes a detection process of detecting, on the basis of user-specified position information in a space and target position information in the space, a plurality of processing targets that is continuously selected by a user from a plurality of selection targets within the space, and a batch operation process of executing a batch operation on the detected plurality of processing targets on the basis of processing policy information indicating a processing policy specified by the user for the detected plurality of processing targets.

At present, technology related to smart homes has become widespread. This technology enables a user to, for example, select and operate a device existing in a living space by a gesture, a voice, or the like.
In association with the technology described above, for example, Patent Document 1 below discloses technology to detect a device to be operated on the basis of the line of sight of the user, and display an operating object for operating the device near the user, where the user uses the operating object to operate the device. In this technology, the user directs his or her line of sight to each of a plurality or devices to collectively select the plurality or devices, and an operating object for operating each of the selected devices is displayed near the user (for example, displayed at hand). Then, the user can operate the device at hand by selecting one device to be operated on the operating object and inputting an operation instruction for the selected device.

Batch information processing apparatus, batch information processing method, and program


A queue management method for a wireless asynchronous transfer mode Network Interface Card (NIC) for integrating computers and other electronic equipment to a Wireless Asynchronous Transfer Mode (WATM) network is constructed so as to efficiently exchange data between a host and the wireless network. In addition to providing both ATM and AAL layer transfer protocols, the NIC also provides Data Link Control (DLC), Media Access Control (MAC), and Radio Physical (RPhy) layers as well.

This invention relates generally to the field of telecommunications and in particular to a queue management method for a wireless Asynchronous Transfer Mode (ATM) network interface card (NIC).
Asynchronous Transfer Mode (ATM) has long been advocated as an important technology for interconnecting wide area heterogeneous networks. In networks constructed utilizing ATM technologies, transported data is divided into small, fixed length units called cells. These cells are further divided into a header and data portion, with the header portion comprising identification, priority and routing information, and the data portion comprising actual data transported between systems.
An important distinguishing characteristic of ATM and networks constructed therefrom, is that it is an end-to-end technology, meaning that with ATM networks the protocols (ATM) are uniform throughout the entire network. That is to say, the ATM on the desktop is the same as the ATM on the Local Area Network (LAN), is the same as the ATM on the Wide Area Network. Consequently, organizations that employ ATM networks do not need extra equipment (like routers or gateways) to interconnect their networks thereby reducing the cost and complexity of the networks while at the same time improving their flexibility.
Due to these and other inherent advantages, there has been widespread and rapid deployment of ATM networks. This rapid deployment of ATM networks, and the contemporaneous need to provide reliable wireless ubiquitous information access to end users, has accelerated the development of Wireless ATM (WATM) networks. Presently, the development of WATM networks is still research oriented, and efforts to specify a standard for its protocol reference architecture are underway. See, for example, the article by D. Raychaudhury et al, entitled "ATM-Based Transport Architecture for Multiservices Wireless Personal Communication Networks", which appeared in Vol. 12, No. 8 of IEEE JSAC in October 1994, or proceedings. An example of a Wireless ATM network which has been prototyped to ascertain the requirements for future WATM network has been described by D. Raychaudhury et al., in an article entitled "WATMnet: A Prototype Wireless ATM System for Multimedia Personal Communication", ICC '96.
In WATMnet, as well as in other WATM networks, a Network Interface Card (NIC) is used to interface a piece of equipment to the WATM network. As can be readily appreciated by those skilled in the art, the architecture of a NIC plays an important role when accessing a high-performance network such as ATM. Specifically, the NIC can become a network bottleneck if its throughput characteristics are not taken into consideration while designing its architecture. Since the Data Link Control Layer (DLC), the Media Access Control Layer (MAC), and RPhy layers are integrated in a WATM NIC, the WATM NIC's processing requirements are more demanding than that of ATM NICS at equivalent transmission rates. (See, for example, R. Dighe et al., "The Multimedia C&C Platform (MCCP), A Network-Centric Architecture for Multimedia", IEEE ATM Workshop '95, October 1995; and C.A. Johnston, "Architecture and Performance of HIPPI-ATM-SONET Terminal Adapters", IEEE Communications, Vol. 33, No. 4, April 1995.) Thus, the design of a high-throughput WATM NIC software/hardware architecture remains a challenging problem.
Critical for the usefulness of such NIC adapters, is an efficient architecture that can allow network communications to proceed in parallel with other operations on a host without excessively slowing down those operations. Also critical to the efficiency of the entire network is a need that the adapter have minimal latency in reception and transmission of data. At the same time, the adapter must be economical to be suitable for accompanying host equipment.
Therefore, a need exists in the art for apparatus and methods which provide for the efficient and flexible wireless interfacing of computer and other electronic devices to ATM networks.

Queue management method for wireless asynchronous transfer mode network interface card


An improved floatboard having a manually operable articulating member formed thereon. The articulating member is designed to assume a first inwardly biased position and a second outwardly extended position. The articulating member is provided with a stop member designed and oriented to engage with a stop surface formed on the floatboard when the articulating member is actuated to assume the second outwardly extended position to thus prevent a catastrophic tear from forming between the articulating member and the floatboard. The articulating member is further preferably provided with a surface that will enable the member to be easily grasped and manipulated. The floatboard of the present invention may additionally be formed to assume the appearance of a particular animal or creature, with the articulating member simulating the jaw or claw of such animal or creature. The floatboard of the present invention may further be fabricated from three (3) layers of polyethylene foam in a sandwich-type arrangement to enhance the durability of the floatboard.

Hand held floatboards are utilized extensively as a means for teaching children how to swim. In this regard, such floatboards provide a safe and fun way to keep a swimmer afloat while he or she practices a swimming motion.
To enhance the fun and enjoyment of using such floatboards, such floatboards may be formed to have the appearance of an animal or some other type of creature, and may further be provided with manually operable articulating members formed to look like the jaws or claws of an animal. By providing such articulating members, the user is thus provided a surface for gripping the floatboard, as well as for moving or operating the jaw or claw formed on the floatboard.
While providing floatboards with such articulating members has several practical advantages and adds fun to the use of the device, the prior art is deficient in providing a floatboard having an articulated member formed thereon that can withstand the rigors of aggressive play and handling. In this respect, such articulating members are typically formed on the floatboard such that the same may be pulled or otherwise deformed beyond their intended range of motion, thus causing the member to partially or completely tear off from the floatboard. As a result, the floatboard becomes permanently damaged and significantly less fun for the swimmer to use.
Accordingly, there is a need in the art for an improved floatboard having at least one manually operable articulating member formed thereon wherein the latter is substantially prevented from being pulled or deformed beyond its intended range of motion when in use. There is additionally a need in the art for such a floatboard where the articulating member is designed to be easily grasped and manipulated. There is still further a need in the art for a floatboard having an articulating member formed thereon that is of simple construction, easy to manufacture, and likewise may be fabricated in the form of a jaw, claw or similar type moving structure to provide fun for the user.

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A method, system and computer program product for managing information is disclosed. The information is stored in a database accessible to a plurality of users. A part of the information is isolated from the database. A user can modify the isolated part of the information. The modified information is compared with the isolated information and a set of changes is extracted from the comparison. The set of changes are appended to the information in the database. Each part of the information in the database has a version associated with it. When changes to a part of the information are appended, the modified part is versioned in an incremental fashion. Prior versions of a part of the information can be accessed and modified by the users.

The present invention relates to the field of enterprise information and planning and more particularly to a method, a system and a computer program product for managing information within an enterprise.
Enterprises today are burgeoning in terms of the number of people employed, the number of departments, and geographic locations. Along with the growth of enterprises, there is a corresponding increase in the amount of information generated within the enterprise. The sources of information are varied in terms of their geographic location and the type of information generated. This variety makes management of information a time consuming and costly task.
The task of managing information includes consolidation of data within documents, storing the data, retrieving the stored data for analysis and representing the retrieved data through a user interface. Sales reports, budgets, requests for proposals and feedback are a few examples of information within an enterprise. Sales reports are obtained from different sales offices, various departments within the enterprise provide their budgets or capital requirements, vendors send requests for proposals (RFP) to order products, and feedback is obtained from customers.
The information obtained from the different sources is used in planning activities by the executives of the enterprise. For example, sales reports and RFP are used to plan production volumes within a manufacturing enterprise. Feedback from customers is utilized in planning new products and improving the existing products. Further, the information provided by the sources may be in various forms. Examples of the forms include e-mails, website forms, and data files such as spreadsheets.
Various sources periodically provide information. Therefore, management of information is not a one-time process. Often, the management of information has to be done on demand, i.e., as and when the information is provided. For example, vendors send RFP as and when they require products. Production volumes, which are dependent on these RFP, need to be updated accordingly.
Various problems can arise while managing information due to the variety of sources and the periodic availability of new information. These problems include a lack of data integrity and security, difficulty in consolidation, and the non-availability of historical data. To ensure data integrity, information that depends on new data values has to be updated accordingly. For example, if new RFP are obtained in a manufacturing enterprise, the planned production volumes that depend on these RFP must be updated accordingly. Data from the various sources must be consolidated in a single place. For example, the data is obtained from e-mails and data files. To reduce the time in consolidation, the data must be automatically extracted from e-mails and data files and then stored. Security must be ensured while managing the information. For example, the executives of an enterprise should have access to information regarding all the departments within the enterprise, but a customer should not have access to this information. Further, in order to use the information for planning, historical information must also be available. This is useful, for example, in identifying trends in data values. Historical data may also be useful if a rollback is required, which involves returning data to previous values. This may be important if, for example, it is found that invalid data was received from a source. Hence, the information must be versioned or chronicled so that data of a particular time or state can be accessed later.
A system for managing information in an enterprise is described in U.S. patent application Ser. No. 20030177135, titled "Multi-user Database for Computer-based Information", filed on Apr. 11, 2003 and assigned to Axon Information Technology Pty. Ltd. The system comprises a multi-user database that stores information as a plurality of data elements. Data files are imported and analyzed to extract the data elements. Data files are analyzed and the data elements are extracted. Amendments to the data elements may be made directly, or by exporting parts of the multi-user database as data files, making changes to the exported data files, and then re-importing the amended data files. Information can be used by structuring the information according to the requirement of a user.
Further, U.S. Pat. No. 5,347,653, titled "System for Reconstructing Prior Versions of Indexes Using Records Indicating Changes between Successive Versions of the Indexes", filed on Jun. 28, 1991 and assigned to Digital Equipment Corporation MA describes a method and a system for versioning information objects in a database. The latest versions of information objects are stored in a complete form. Prior versions are saved only as delta changes, which are the changes that take place between the prior versions and the latest version. In this way, prior versions can be recreated from the latest versions.
However, the systems mentioned above do not provide a complete solution for managing information within an enterprise, while addressing all the problems mentioned before. Hence, there exists a need for a method and a system for managing information within an enterprise that allows viewing, comparing and reverting to historical data. The system should allow information to be viewed in a manner, which is useful to the executives of an enterprise. It should also allow the executives to compare current information with previous information and analyze trends. Further, the system should also allow reversion to a previous state. Finally, it should also address the problems arising due to lack of data integrity and security, and difficulty in consolidation.

Method and system for versioned sharing, consolidating and reporting information


A polarization controlled laser system receiving a pump laser beam includes a long laser cavity for precluding mode hopping. Preferably, the long laser cavity is defined by first and second dichroic reflectors, a rare earth doped optical fiber disposed between the first and second dichroic reflectors for amplifying the pump laser beam to thereby produce an amplified laser beam, a polarization controller for controlling polarization of the amplified laser beam, and a polarization selector for selecting the polarization of the amplified laser beam. The polarization selector can include a polarizing optical fiber while the polarization controller advantageously may include a polarization maintaining optical fiber. Alternatively, the rare-earth doped optical fiber, the polarization controller, and the polarization selector are all formed from a single polarizing rare-earth doped optical fiber. The polarization controlled laser system may be converted to a frequency doubled polarization controlled laser system by adding a doubling crystal to the long laser cavity. Methods for generating polarization controlled laser beams using a long laser cavity formed from a rare-earth doped optical fiber are also described.

The present invention relates generally to long cavity laser systems. More specifically, the present invention relates to long cavity fiber optic laser systems, particularly frequency doubling long cavity laser systems using at least one optical fiber amplification component. Methods for generating polarization controlled laser beams using a long laser cavity formed from a rare-earth doped optical fiber are also disclosed.
At the present time, the development of new solid state media excited by high-power semiconductor lasers is an extremely active field. As a result of this work, compact systems which produce high quality beams in the near infrared have been developed. When harmonic generation techniques are utilized, compact lasers in the blue-green region of the spectrum are created. Such devices are presently of great interest because of their many applications, particularly in high density optical storage. U.S. Pat. Nos. 4,841,528, 4,887,270, 5,363,390, 5,390,210, 5,420,876, 5,450,429, and 5,479,431, which patents are incorporated herein by reference for all purposes, disclose typical frequency doubled laser systems capable of emitting a green laser light. It will be appreciated that the majority of these systems utilize short laser cavities; some of the disclosed systems utilize folded laser cavities.
A short laser cavity suffers from power fluctuations because of competition between the longitudinal modes within the laser cavity. It will be appreciated that in a short laser cavity, only a few longitudinal modes are operating at any given instant. The gain for any particular longitudinal mode is suppressed by cross saturation, both spatially and temporally, by power in other oscillating longitudinal modes. Since each longitudinal mode intersects and saturates a different volume of the gain medium, the gain for longitudinal modes that do not efficiently couple to the volume of the gain medium supporting the primary longitudinal mode can increase over time as inverted populations build up in those under-extracted volumes. In particular, the gain of such longitudinal modes can then actually exceed the gain of the then-current dominant longitudinal mode. When this happens, the frequency of the primary mode, and its frequency-doubled replica, jump to the new longitudinal mode, thereby causing a power spike and an attendant, subsequent power fluctuation. It will be appreciated that these fluctuations in the mode spectrum behave chaotically. Moreover, as mentioned above, these fluctuations in the mode spectrum are reflected in the amplitude spectrum of the frequency-doubled signal.
In contrast, a long laser cavity does not suffer from the above-described instability problems. Advantageously, a large number of modes oscillate in a long laser cavity and have sufficient overlap spatially that the gain in the laser rod is essentially homogenized to look approximately the same to all of the modes. The overall effect is that the amplitudes of the oscillating modes fluctuate less. In addition, if one longitudinal mode is overcome or quenched by another longitudinal mode, it is often only one of hundreds of lines oscillating in the long laser cavity. It will be appreciated that there is little or no effect on the total power emitted by the laser when one or more lines are quenched.
Thus, a frequency doubled laser using a medium such as Nd:YAG is highly unstable when a short laser cavity is used as the primary laser. The use of a relatively long laser cavity, i.e., long enough to permit stable operation, alleviates this instability problem.
One approach to building a frequency doubled laser using a long laser cavity was recently proposed by workers at the Semiconductor Laser Technology Branch of the Philips Laboratory (PL/LIDA), under funding from the U.S. Air Force. The proposed frequency doubled laser included a folded resonator design and used one or more discrete, end-pumped Nd:YAG rods, Different diode pump arrays were optically coupled to the rod(s) using either lenses or optical fibers.
The resonator was implemented as shown in FIG. 1A, wherein a single Nd:YAG rod (R1) is used as an active mirror in an inverse Z resonator configuration. The rod R1 was high-reflectivity (HR)-coated at 1064 nm and anti-reflection (AR)-coated at 808 nm on the rear (pump) surface and AR-coated at 1064 nm on the front surface. The resonator end mirrors (M1 and M3) were both HR-coated at 1064 nm; the end mirror in the frequency doubling leg (M3) was also HR-coated at 532 nm. The output coupler (M2) was HR-coated at 1064 nm on one surface and AR-coated at 532 nm on both surfaces.
It will be appreciated that the inverse Z resonator design allows implementation of an alternative two rod configuration as shown in FIG. 1B, wherein mirror M1 is replaced by a second Nd:YAG rod (R2). This allows pumping of each rod with a high-power laser diode, resulting in scaling to higher powers while alleviating gain media thermal loading. It will also be noted that three Nd:YAG rods (not shown) can be used in a Z-resonator when each rod is separately pumped. It should be noted that all of the inverse Z-resonator configurations employ an intracavity frequency doubling crystal (C1) made from a single piece of potassium titanyl phosphate (KTP). The KTP was mounted in a holder which allowed xyz translation, moderate xy tilt, and 360-degree rotation about the resonator axis.
As discussed briefly above, either conventional optics or optical fibers were used to couple the output of a laser diode bar or array to the Nd:YAG rod(s). In one instance, a four lens beam shaping train, i.e., three cylindrical lenses and one spherical lens, was used to focus the output of a laser diode array into the Nd:YAG rod. Later experiments used a fiber coupled diode array which was first collimated with a Melles Griot 8 mm lens and then focused into the Nd:YAG rod with a 31.7 mm spherical lens; both lenses were AR-coated at 830 mm.
It should be noted that although optical fibers were employed in the inverse Z resonator depicted in FIGS. 1A and 1B, the use of optical fibers in place of the inverse Z resonator did not occur to the system designers. From FIGS. 1A and 1B, it will also be appreciated that lengthening of the laser cavity by folding the cavity using reflectors requires careful alignment during the final stages of assembly. Moreover, the use of discrete elements dictates that a robust frequency doubled laser using a long laser cavity will require commensurate support elements, thus increasing the size and weight of the overall laser apparatus.
What is needed is a frequency doubled laser system which is compact and which provides excellent power stability. Additionally, what is needed is a frequency doubled laser system which is light in weight and which is not prone to alignment problems.

Long cavity laser system including frequency doubling long cavity fiber optic laser system


A optical connector device, which comprises a two-dimensional optical waveguide layer; a semiconductor laser having a function capable of switching a plurality of different oscillation modes; and an optical path converting structure for converting an optical path of an outgoing light from the semiconductor laser, in which the optical path converting structure is disposed within the two-dimensional optical waveguide layer such that a radiation angle of the semiconductor laser changes within the two-dimensional optical waveguide layer upon switching over the oscillation mode of the semiconductor laser, and the outgoing light from the semiconductor laser propagates in the two-dimensional optical waveguide layer.

1. Field of the Invention
The present invention relates to an optical connector device which allows information transmission by light through a two-dimensional optical waveguide layer between a sending port having a function of sending an optical signal and a receiving port having a function of receiving an optical signal, and to an optical and electrical circuit combined board on which an electrical wiring layer and an optical circuit layer are laid together.
2. Related Background Art
Nowadays, mobile phones and personal information terminals are rapidly becoming widespread, while such equipment has an increasing demand for a further smaller size, lighter weight, and higher performance. However, the smaller size, lighter weight, and higher performance entail an increasingly higher speed and higher packing density of a circuit board, causing an urgent necessity to cope with various problems such as occurrence of a signal delay or electromagnetic interference (EMI, electromagnetic interference noise). Expected as a countermeasure to solve those problems is a technique for optical circuit that is capable of high-speed transmission and has solutions to the signal delay, signal degradation, and the electromagnetic interference noise radiated from wirings, which are problems with conventional electrical circuit.
As an example of using an advantage of the optical circuit, JP 2000-199827 A discloses a device using a mirror tilted by 45° in order to efficiently couple to an optical waveguide an outgoing light or an incident light which are perpendicular thereto.
However, since the device disclosed in JP 2000-199827 A uses a 45° mirror in order to couple light to the optical waveguide and to couple light propagating in the optical waveguide to a light-receiving device, a transmission path becomes a linear path. In the case of forming a plurality of transmission paths, positions of a light-emitting device and the light-receiving device are limited, reducing a degree of freedom in design. That is, the above device does not sufficiently utilize characteristics of the optical waveguide, and lacks flexibility in providing the optical circuit.
Furthermore, U.S. Pat. No. 5,191,219 discloses the following information processing apparatus. That is, U.S. Pat. No. 5,191,219 discloses an information processing apparatus comprising means forming a planar optical waveguide which extends in two dimensions and serves as a shared medium, a plurality of light-emitting means and a plurality of light-detecting means extending in a two dimensional arrangement over said planar optical waveguide for broadcasting light signals and abstracting light signals, respectively, into and from said planar optical waveguide and a plurality of subsystems including input and output ports for processing the light signals in the shared medium, the light-detecting means being coupled to input ports and the light-detecting means being coupled to output ports of the subsystems.
However, the information processing apparatus disclosed in U.S. Pat. No. 5,191,219 does not have sufficient flexibility in providing the optical circuit, either.

Optical connector device, and optical and electrical circuit combined board using the same


Conjugates of a polymer having attached thereto an angiogenesis targeting moiety and a therapeutically active agent such as an anti-cancer agent or anti-angiogenesis agent, and processes of preparing same are disclosed.

The present invention, in some embodiments thereof, relates to novel chemical conjugates and to uses thereof in therapy and diagnosis and, more particularly, but not exclusively, to novel conjugates of polymers having attached thereto an angiogenesis targeting moiety and an anti-angiogenesis agent and to uses thereof in monitoring and treating medical conditions associated with angiogenesis.
Angiogenesis is a biological process that involves the sprouting of new blood vessels from pre-existing ones and plays a crucial role in disease development and progression. Angiogenesis is a complex process in which endothelial cells serve as a building block for blood vessel expansion. This process involves an extensive interplay among cells, growth factors, and extracellular membrane (ECM) components. It is regulated through a fine balance between pro-angiogenic and anti-angiogenic molecules.
Pathological angiogenesis has been demonstrated in several diseases, including atherosclerosis, cancer, hypertension, rheumatoid arthritis, diabetes and diabetes related complications such as diabetic retinopathy. Tumor growth and metastasis are particularly dependent on the degree of angiogenesis. Tumor angiogenesis is the proliferation of a network of blood vessels that penetrate into cancerous tumors in order to supply nutrients and oxygen and remove waste products, thus leading to tumor growth. Tumor angiogenesis involves hormonal stimulation and activation of oncogenes, expression of angiogenic growth factors, extravasation of plasma protein, deposition of a provisional ECM, degradation of ECM, and migration, proliferation and elongation of endothelial capillaries.
Inhibition of further vascular expansion has therefore been the focus of active research for cancer therapy. Many drugs have been developed, which target different steps in this multi-step tumor angiogenesis process. However, most of these drugs were shown to be cytostatic rather than cytotoxic and thus do not cause a substantial reduction of tumor volume during the first stage of treatment.
There are currently eight approved anti-cancer therapies with recognized antiangiogenic properties. These agents, which interrupt critical cell signaling pathways involved in tumor angiogenesis and growth, can be divided into two primary categories: (1) monoclonal antibodies directed against specific proangiogenic factors and/or their receptors; (Avastin, Erbitux, Vectibix, Herceptin) and (2) small molecule tyrosine kinase inhibitors (TKIs) of multiple proangiogenic growth factor receptors (Tarceva, Nexavar, Sutent, Iressa). Inhibitors of mTOR (mammalian target of rapamycin) represent a third, smaller category of antiangiogenic therapies with one currently approved agent (Torisel). In addition, at least two other approved angiogenic agents may indirectly inhibit angiogenesis through mechanisms that are not completely understood (Velcade, Thalidomide/Celgene)
The first FDA-approved angiogenesis inhibitor, Bevacizumab (Avastin, Genentech) a monoclonal antibody to vascular endothelial growth factor (VEGF), has recently been approved for metastatic colon cancer treatment in conjunction with standard conventional chemotherapy.
The largest class of drugs that block angiogenesis are the multi-targeted tyrosine kinase inhibitors (TKIs) that target the VEGF receptor (VEGFR). These drugs such as sunitinib (Sutent, Pfizer), Sorafenib (Nexavar, Bayer/Onyx Pharmaceuticals) and Erlotinib (Tarceva, Gennentech/OSI/Roche) have the advantages of hitting multiple targets, convenient oral administration, and cost effectiveness. While these drugs exhibit promising efficacy, their use is limited by their lack of target specificity, which leads to unexpected toxicity [Cabebe et al. Curr Treat Options Oncol 2007; 8:15-27].
Tumor endothelial cells are drug sensitive for long time periods and may be treated with cytotoxic agents in an "anti-angiogenic dosing schedule". This dosing schedule involves the administration of chemotherapy in low doses, well below the maximum tolerated dose (MTD), in close intervals for extended periods of time ("metronomic dosing"). As a result, acute toxicity should be avoided and the drugs may be administered during longer periods, eventually converting cancer to a chronic manageable disease.
The microtubule-interfering agent Paclitaxel (PTX) is a clinically well-established and highly-effective anti-neoplastic drug used as a monotherapy and in combination therapy mainly for the treatment of prostate, breast, ovarian, and non-small cell lung cancers and it is the drug of choice for the treatment of metastatic breast cancer. It has also shown anti-angiogenic and pro-apoptotic properties [Oldham et al. 2000 Int. J Oncol. 16:125-132]. However, due to the hydrophobic nature of the drug, solubilizing agents such as Cremophor EL or ethanol are required for its administration. PTX causes severe adverse side effects such as neutropenia, neuropathies, and when solubilized in Cremophor EL causes hypersensitivity reactions. In addition, only a small amount of the drug localizes in the tumor and the drug is substrate to efflux pumps in particular p-glycoprotein, resulting in multiple drug resistance.
Water-soluble copolymers such as hydroxypropyl methacrylate (HPMA) and PGA are biocompatible, non-immunogenic and non-toxic carriers that enable specific delivery into tumor tissue (Satchi-Fainaro et al. Nat Med 2004; 10: 255-261). These macromolecules do not diffuse through normal blood vessels but rather accumulate selectively in the tumor site because of the enhanced permeability and retention (EPR) effect. This phenomenon of passive diffusion through the hyperpermeable neovasculature and localization in the tumor interstitium is observed in many solid tumors for macromolecular agents and lipids.
Conjugation of anti-cancer drugs to copolymers, such as HPMA or PGA, has been suggested so as to restrict the passage through the blood brain barrier and to prolong the circulating half-life of the drugs, hence inhibiting the growth of tumor endothelial and epithelial cells by exposing the cells to the conjugated drugs in the circulation for a longer time compared to the free drugs.
U.S. Pat. No. 6,884,817 teaches compositions comprising a chemotherapeutic and/or anti-angiogenic drug, conjugated to a water-soluble polyamino acid or soluble metal chelator. The taught compositions provide water soluble taxoids which overcome the drawbacks associated with the insolubility of the drugs themselves, and further improve the delivery of the drugs to tumor tissue and affect a controlled release of the conjugated drug. According to the teachings of in U.S. Pat. No. 6,884,817, an exemplary such conjugate of the anti-cancer drug paclitaxel and polyglutamate, exhibited superior antitumor activity together with a reduced level of toxicity, as compared with the anti-tumor agent paclitaxel alone.
The conjugate paclitaxel-polyglutamate OPAXIO™ (paclitaxel poliglumex, CT-2103) (Formerly known as XYOTAX™) showed promising results in phase III trials and is currently being evaluated for marketing approval.
U.S. patent application Ser. No. 12/117,678 having publication No. 2008/0279778 also teaches polyglutamate polymers conjugated to a plurality of drugs for use in drug targeting, stabilizing and imaging applications. A HPMA copolymer conjugate of paclitaxel has also been described by Meerum Terwogt et al. [Anticancer drugs 2001; 12:315-323]. This conjugate was aimed at improving drug solubility and providing controlled release of paclitaxel. In this conjugate, the paclitaxel is linked to the HPMA copolymer through an ester bond, and is hence released from the polymer by non-tissue specific hydrolytic or enzymatic (esterases) degradation of the ester bond, thereby inducing the commonly observed toxicities of paclitaxel.
WO 03/086382 teaches conjugates of water-soluble polymers and the anti-angiogenesis agent TNP-470, and their use as anti-tumor agents, in particular their use as carriers of TNP-470 into tumor vessels, and their effect on the neurotoxicity of TNP-470. According to the teachings of WO 03/086382, an exemplary such conjugate, HPMA-(TNP-470) conjugate (caplostatin), exhibited superior antitumor activity together with a reduced level of toxicity, as compared with TNP-470 alone.
WO 03/086178 teaches a method for decreasing or inhibiting disorders associated with vascular hyperpermeability by the administration of an effective amount of an anti-angiogenesis compound or a compound capable of increasing cell-cell contacts by stabilizing tight junction's complexes and increasing contact with the basement membrane. The compounds taught by WO 03/086178 are endostatin, thrombospondin, angiostatin, tumastatin, arrestin, recombinant EPO, and polymer conjugated TNP-470. According to the teachings of WO 03/086178, an exemplary such conjugate, HPMA-(TNP-470) inhibited vascular endothelial growth factor (VEGF)-induced vessel hyperpermeability and inhibited endothelial cell mediated angiogenesis both in vitro and in vivo.
Integrins are a class of receptors involved in the mechanism of cell adhesion. Alterations in the function of these receptors are responsible for the occurrence of a number of pathologic manifestations, such as, for example, defective embryogenesis, blood coagulation, osteoporosis, acute renal failure, retinopathy and cancer, particularly metastasis. Since the 1980s it is well recognized that integrins play a key role in cell matrix interactions and hence in angiogenesis.
The integrins are heterodimeric transmembrane glycoproteins that compose a diverse family of 19α and eight β subunits. An integrin with a well-characterized involvement in angiogenesis and tumor invasiveness is αvβ3. The αvβ3 integrin is a molecular marker that differentiates newly formed capillaries from their mature counterparts. This integrin is expressed in various malignant tumors. Inhibition of the αvβ3 mediated cell matrix interaction leads to apoptosis of activated endothelial cells and to disruption of blood vessel formation. In contrast, αvβ3 is not strongly expressed on quiescent endothelial cells, thus treatment with αvβ3 antagonists does not affect pre-existing blood vessels [Brooks et al. Science 1994; 264:569-571].
αvβ3 integrins therefore play an important role in adhesion, motility, growth and differentiation of endothelial cells. αvβ3 integrins are known to bind the RGD sequence (Arg-Gly-Asp; SEQ ID NO:1), which constitutes the recognition domain of different proteins, such as laminin, fibronectin and vitronectin. The RGD sequence represent the minimal amino acid domain, in several extracellular matrix proteins, which has been demonstrated to be the binding site of the transmembrane integrins proteins family [Bazzoni et al. 1999, Current Opinion in Cell Biology; (11) pp. 573-581]. Indeed it was shown that replacement of even a single amino acid of this short sequence results in loss of binding activity to integrins. Integrins mediates the attachment of endothelial cells to submatrix proteins that form the basement membrane of the capillary. Although all endothelial cells use the integrin to anchor to the extraluminal submatrix, the αvβ3 integrins are found on the luminal surface of the endothelial cell only during angiogenesis. Thus, agents that target this integrin actually target endothelial cells involved in angiogenesis.
The αvβ3 integrin is overexpressed on proliferating endothelial cells such as those present in growing tumors, as well as on some tumor cells of various origins. Expression of endothelial αvβ3 integrin receptor in aggressive breast carcinomas and glioblastomas is a marker of poor prognosis.
It has been demonstrated that RGD-containing peptides, either isolated from phage peptides library or biochemically synthesized, were able to compete with extracellular matrix proteins on binding to integrins [Haubner et al. 1997, Angew. Chem. Int. Ed. Engl.; (36) pp. 1374-1389]. Tumor-induced angiogenesis can be targeted in vivo by antagonizing the αvβ3 integrin with small peptides containing the RGD amino acid sequence.
It has been further found that the substrate specificity of RGD-containing peptides results from the different conformations of the RGD sequence in different matrix proteins. For example, the bis-cyclic peptide E-[c(RGDfK)2] (SEQ ID NO:2) is a ligand-based vascular-targeting agent that binds to integrin αvβ3.
Encoded by a growth factor-inducible immediate-early gene, Cyr61 (also known as CCN1) is a cysteine-rich matricellular protein that supports cell adhesion and induces adhesion signaling. Furthermore, Cyr61 stimulates endothelial cell migration and enhances growth factor induced DNA synthesis in culture and therefore induces angiogenesis in vivo. Mechanistically, Cyr61 acts as a non-RGD-containing ligand of integrin receptors. Functional blockade of αvβ3, a Cyr61 integrin receptor, is specifically cytotoxic towards Cyr61-overexpressing breast cancer cells and a specific αvβ3-RGD peptidomimetic agent prevents αvβ3 from binding to its ligand, Cyr61.
Cyr61 plays a key role in both the maintenance and the enhancement of a malignant phenotype in breast cancer. Cyr61 is overexpressed in about 30% of invasive breast carcinomas, whereas Cyr61 expression levels in normal breast tissues are negligible. It has been recently shown that Cyr61 overexpression can render human breast cancer cells highly resistant to Paclitaxel. Pharmacological interference with the Cyr61/αvβ3 interaction fully restores Paclitaxel efficacy in Cyr61 overexpressors, thus implying that a previously unrecognized Cyr61/αvβ3-driven cellular signaling actively modulates breast cancer cell growth and chemosensitivity.
Chen et al. reported [J. Med. Chem. 2005; 48:1098-1106] the synthesis and antitumor activity of paclitaxel (PTX) conjugated with a bis-cyclic RGD (E[RGDyK]2) (SEQ ID NO:3) in a metastatic breast cancer cell line.
Mitra et al. report [Journal of Controled Release 2006; 28: 175-183] the biodistribution and tumor targeting properties of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer based conjugates of mono-(RGDfK) (SEQ ID NO:4) and doubly cyclized (RGD4C; SEQ ID NO:5) αvβ3 binding peptides.
WO 2006/012355 teaches an anti-angiogenic polymer conjugate (APC) for treatment of solid tumors comprising a chemical moiety targeting cell-surface proteins of endothelial cells at an angiogenic site. The chemical moiety taught in the application may be a ligand such as RGD4C (SEQ ID NO:5) or RGDfK (SEQ ID NO:4) for a cell-surface receptor, such as, for example, an integrin. The polymer conjugate taught by WO 2006/012355 may further comprise at least one side chain comprising a chelator capable of chelating a pharmaceutically acceptable radioactive label. The scintigraphic images and biodistribution of an exemplary such conjugate, HPMA copolymer-RGD4C-99mTc conjugate (SEQ ID NO: 6), indicated specific in vivo tumor targeting as well as prolonged retention of the conjugate at the tumor site. Treatment of SCID mice bearing DU145 human prostate carcinoma xenografts with another exemplary conjugate, HPMA copolymer-RGD4C comprising the beta particle emitter 90Y (SEQ ID NO:7), resulted in significant decrease of tumor volume as compared to the control (also reported by Mitra et al. in [Nuclear Medicine and Biology 2006; 33:43-52])
Wan et al. [2003 Proc. Intl Symp. Control. Rel. Bioact. Mater. Vol 30: 491-492] teach targeting endothelial cells using HPMA copolymer-doxorubicin-RGD conjugates (SEQ ID NO:8).

This patent is subject to a terminal disclaimer.

Conjugates of polymers having a therapeutically active agent and an angiogenesis targeting moiety attached thereto and uses thereof in the treatment of angiogenesis related diseases

Abstract: Pharmaceutical compositions containing these conjugates and uses thereof in the treatment of angiogenesis-related medical conditions such as cancer and cancer metastases are also disclosed.

Fundacion de la Comunidad Valenciana Centro de Investigacion Principe Felipe


An optical fiber includes a core region and a cladding region formed on an outer circumference of the core region. The cladding region includes a plurality of holes arranged around the core region and has a refractive index lower than a refractive index of the core region. A zero dispersion wavelength of the optical fiber is shorter than 1150 nanometers. The optical fiber propagates a light having a wavelength longer than 1000 nanometers exclusively in a fundamental mode of LP01 mode. An effective core area of the optical fiber is equal to or smaller than 12.0 μm2 at a wavelength of 1064 nanometers.

1. Field of the Invention
The present invention relates to an optical fiber and an optical device employing the optical fiber.
2. Description of the Related Art
In recent years, a laser light source that outputs a high-power laser light having a wavelength near 1000 nanometers has been matured, which includes yttrium aluminum garget (YAG) laser having an oscillation wavelength of 1064 nanometers and an optical fiber laser using a ytterbium-doped optical fiber (YDF) having an oscillation wavelength of 1100 nanometers. With the development of such a laser light source, a nonlinear optical device is getting an attention, such as a supercontinuum light generation device using the laser light source as a pumping light source. An optical fiber used in such a nonlinear optical device is required to have the zero dispersion wavelength near the wavelength of the pumping light with high optical nonlinearity.
In the case of a generally-used single-mode optical fiber, which is made of silica-based glass, the wavelength dispersion characteristic is represented by a sum of the structure dispersion and the material dispersion. The structure dispersion is a wavelength dispersion determined by the refractive index profile of the optical fiber, and the material dispersion is a wavelength dispersion determined by the optical characteristics of the silica-based glass that is the main constituent material of the optical fiber. Because the characteristic of the structure dispersion can be largely changed by changing the refractive index profile of the optical fiber, it is possible to set the zero dispersion wavelength at which the wavelength dispersion becomes zero to a desired wavelength by adjusting the structure dispersion of the optical fiber.
Nevertheless, the wavelength where the zero dispersion wavelength can be easily set by adjusting the structure dispersion is equal to or longer than 1200 nanometers, and it is difficult to set the zero dispersion wavelength to a wavelength shorter than 1200 nanometers. The reason is as follows. The material dispersion of the silica-based glass has a positive value at a wavelength side longer than a wavelength of about 1300 nanometers, showing an anomalous dispersion. However, it becomes negative at a wavelength of about 1300 nanometers, showing a larger normal dispersion as the wavelength becomes shorter at a region of a short wavelength side. On the other hand, the structure dispersion is basically a normal dispersion at a wavelength side longer than about 1000 nanometers, and even if the structure dispersion is shifted to the anomalous dispersion side by changing the refractive index profile, the absolute value of the dispersion is small. For this reason, the wavelength dispersion of the optical fiber, which is the sum of the material dispersion and the structure dispersion, becomes negative. As a result, it is difficult to set the zero dispersion wavelength to a wavelength shorter than 1200 nanometers.
Meanwhile, an optical fiber commonly known as a photonic crystal fiber has been reported, which has a large number of holes around the core region made of silica glass. Regarding the photonic crystal fiber, there are reports saying that the structure dispersion with a larger absolute value can be obtained (see T. A. Birks, et al., "Dispersion compensation using single-material fibers", Photon. Tech. Lett., 11, p 674 (1999) and J. C. Knight, et al., "Anomalous dispersion in photonic crystal fiber", Photon. Tech. Lett., 12, p 807 (2000)). In addition, another report says that a single-mode operation and the zero dispersion wavelength characteristic can be obtained at any wavelength by using the structure obtained by forming such holes in the photonic crystal fiber (see P. J. Bennett, et al., "Toward practical holey fiber technology: fabrication, splicing, modeling, and characterization", Opt. Lett., 24 p 1203 (1999)). In the photonic crystal fiber, the refractive index profile of the optical fiber can be largely changed by arranging as large number of holes as 60 to 300 in the cladding region, which makes it possible to obtain the structure dispersion with a large absolute value. With this mechanism, for example, a large anomalous dispersion can be obtained at a short wavelength region of the near infrared, and therefore the wavelength dispersion can be made zero by combining with the material dispersion having a large normal dispersion. In the photonic crystal fiber, the wavelength dispersion characteristic largely depends on the size of the holes and the accuracy of arranging the holes. However, because it is difficult to fabricate the optical fiber in which such a larger number of holes are accurately arranged, the manufacturing yield becomes decreased resulting in an increase of cost. Furthermore, in the photonic crystal fiber, a dopant for increasing the refractive index, such as germanium, is not doped in the core region, and the effective refractive index of the core region is low, which easily causes a large optical leakage loss. Because a large number of hole layers are necessary to suppress the leakage loss, the total number of holes cannot be reduced, which causes a further decrease of the manufacturing yield and a further increase of cost.
On the other hand, an optical fiber in which a number of holes are arranged around a core region doped with the germanium has been reported, which is called the hole-assisted fiber (see T. Hasegawa, et al., "Novel hole-assisted lightguide fiber exhibiting large anomalous dispersion and low loss below 1 dB/km", OFC 2001, D5-1 (2001)). The features of the hole-assisted fiber are: it is possible to reduce the macro-bending loss because a strong optical confinement in the core region can be obtained by providing the holes; and the structure dispersion can be largely changed by providing the holes near the core region. In addition, unlike the photonic crystal fiber, because the hole-assisted fiber includes a core region having a refractive index higher than that of a cladding region, the effective refractive index of the core region is higher than the refractive index of the cladding region, which makes it possible to easily suppress the optical leakage loss even without providing a large number of hole layers.
However, regarding a single-mode optical fiber that has the zero dispersion wavelength at a wavelength near 1000 nanometers and is particularly suitable for a nonlinear optical device in this wavelength band, the photonic crystal fiber is not a good candidate because it is difficult to fabricate the fiber, which increases the cost. Furthermore, in the case of the hole-assisted fiber, the shift of the zero dispersion wavelength to a wavelength near 1000 nanometers by controlling the structure dispersion increases the optical confinement, which leads the light to easily propagate in a higher-order mode, and therefore a single-mode operation at the zero dispersion wavelength becomes hard to obtain.


An array of antenna feed elements includes a plurality of horns, each horn having an aperture and configured for transmission of electromagnetic energy therethrough. At least a first horn is configured with an electrically conductive external surface proximate to the aperture, the external surface contoured so as to reduce mutual coupling between the first horn and an adjacent horn. Where the electromagnetic energy is within a radio frequency (RF) band, the external surface is contoured so as to provide an abrupt change in a gap dimension between the first horn and an adjacent horn, the change occurring at a distance behind the aperture of equal to a multiple of one half the characteristic wavelength of the RF band.

The assignee of the present invention manufactures and deploys spacecraft for, inter alia, communications and broadcast services. Antenna systems for such spacecraft may include array-fed reflectors, for generating shaped beams corresponding to specific antenna pattern coverage requirements.
A feed array configured for the transmission of RF energy therethrough may be communicatively coupled with an antenna reflector and may include an array of multiple feed elements configured as horns. Center-to-center spacing dc-c between adjacent horns in such a feed array is, desirably, made as small as possible in order to provide a maximal degree of pattern control for the shaped beam. For horns having a circular aperture, based on cutoff of the dominant circular waveguide mode, dc-c should be no less than approximately 1.2λ, where λ is the wavelength corresponding to the lowest frequency of the RF energy (the "characteristic wavelength"). Moreover, dc-c must exceed the horn aperture outer diameter, da, so as to ensure a positive "gap" between horns at the aperture plane. This gap may be for example, about 1/20th of the aperture diameter.
Aperture efficiency, which may be characterized by a metric referred to as peak directivity, is a critical performance metric for feed array elements. For example, the achievable edge of coverage (EOC) secondary pattern directivity for the shaped beam directly tracks the radiating element's peak directivity. A 0.1 dB decrease in primary pattern peak directivity may result in a 0.1 dB decrease in secondary pattern EOC directivity.
Other important performance metrics for the feed array elements include polarization purity (or, equivalently, suppression of cross polarization) and radiation efficiency, i.e., the fraction of available power that is actually radiated by the element. Radiation efficiency incorporates the effects of impedance mismatch (return loss) and dissipation loss.
For closely spaced arrays, mutual coupling between neighboring elements can perturb and degrade the radiating elements' performance as reflected in one or more of the above mentioned metrics.
Performance degradation due to mutual coupling must be accommodated in communication system link budgets or suppressed. Known suppression techniques entail the use of additional components arranged between the radiating elements. For example, U.S. Pat. No. 2,987,747 to Atchison discloses that adjacent radiating elements may be shorted together at a distance of one quarter wavelength from a common aperture plane, generating an RF choke that inhibits mutual coupling. U.S. Pat. No. 4,115,782 to Han discloses metal tabs or clips inserted near the apertures of radiating elements to reduce mutual coupling effects. U.S. Pat. No. 4,219,820 to Crail discloses a planar metallic shape etched on a dielectric substrate that is inserted into the aperture of circular horn elements to provide coupling compensation between circularly polarized horn antennas to reduce degradation of polarization purity. Techniques disclosed in the above mentioned references rely, undesirably, on additional components, the installation, calibration and test of which add appreciably to the cost of the array, and which represent additional failure mechanisms that detract from the array's reliability.
Thus, improved techniques for reducing mutual coupling between radiating elements are desirable.

Antenna array with reduced mutual coupling between array elements