Small Antennas for Cognitive Radio Using Negative Impedance Converters
There is a need for small antennas in mobile and handheld cognitive radios. These antennas are also required to be either wideband or have a wide tuning range. The authors used a non-Foster matching network to achieve wideband matching and also demonstrate tuning. They also simulated the noise and Inter-Modulation (IMD) performance of the matching network. A recent survey carried out by the FCC within the 30MHz - 3GHz band showed that the licensed band of the frequency spectrum is underutilized but on the contrary, unlicensed frequency bands experience higher utilization.