r evi- dence that more of these novel applications are likely in an ever-increasing range of devices. 6.6.1 Vehicular Radar Futurists have long predicted the creation of a vehicle-based radar system that would allow cars, trucks, and buses to safely avoid obstacles, even in zero- visibility conditions. High cost and bulky equipment have SO far frustrated numerous attempts to create a practical vehicle radar, but help may soon be on the way. That's because California Institute of Technology researchers have built the world's first radar on a chip, implementing a novel antenna array system on a single, silicon device. The chip contains both a transmitter and receiver (more accurately, a phased-array transceiver) and works much like a conventional antenna array. But unlike conventional radar, which involves the mechanical movement of hardware, Caltech's as-yet-unnamed chip uses an electrical beam that can steer the signal in a given direction in space without any mechanical movement. In cars, an array of the chips-one each in the front, back, and right and left sides-could provide a smart cruise control. Such a system wouldn't just keep the pedal to the metal, but would brake for a slowing vehicle ahead, avoid a SOMETHING IN THE AIR-RADIO AND LOCATION TECHNOLOGIES car that suddenly dodges in front, or evade an obstacle that suddenly appears in the vehicle's path. There are other radar systems in development for cars, but these consist of a large number of modules that use more exotic and expensive technologies than silicon. The Caltech chip could prove superior because of its fully inte- grated nature, which allows it to be manufactured at a substantially lower price and makes the chip more robust in response to design variations and changes in the environment, such as heat and cold. "Traditional radar costs a couple of million dollars," says Ali Hajimiri, an associate professor of electrical engi- neering at Caltech and the project's leader. "It's big and bulky and has thou- sands of components. This integration in