cy it is possible to excite very different radiation modes, resulting in low correlation, however, although it is possible to excite higher-order modes even at frequencies <1 GHz, with fields confined near the antenna and with a radiation pattern different from that of the fundamental mode, these modes have an extremely narrowband and are not suitable for this application. The counterargument to this is that 700 and 800 MHz networks will probably need to support smaller form factor devices including dongles, smart phones and standard phones in order to amortise spectral and network investment over a broad user-product mix. Not to do SO would place these networks at a commercial disadvantage. Making Telecoms Work 5.6.3 Antennas in Smaller Form Factor Devices Including Smart Phones A traditional PIFA antenna uses the ground plane as a significant part of the antenna. PIFA antennas tend to have a natural broadband response due to their effective large size due to the interaction with the ground plane but this increases interaction between other antennas and increases susceptibility to hand capacitance effects. Unwanted coupling becomes a particular issue at lower frequencies. Antennas in space-constrained designs are a fraction of the resonance length, and radiation efficiency and bandwidth are a function of volume. Space needs to be left around the antenna to avoid power being shorted out of the device. The antenna is shielded by the user's hand or head and the antenna needs enough bandwidth (a function of volume) to resist detuning. Antenna designs also need to comply with regulatory requirements for SAR and HAC. 5.6.4 SISO Testing28 Antennas in user equipment have morphed from a folding or whip antenna in first-generation devices to smaller helical designs to the first integral patch antenna in 1994, the first of many patch antenna implementations. From an aesthetic perspective patch antennas were a great leap forward, from a performance perspective a potential significant step back. Antenna- performance concerns