Compact fifth-generation (5G) low-frequency band filtering antennas (filtennas) with stable directive radiation patterns, improved bandwidth (BW), and gain are designed, fabricated, tested in this research. The proposed filtennas achieved by combining the predesigned compact 5G (5.975 – 7.125 GHz) third-order uniform non-uniform transmission line hairpin bandpass filters (UTL NTL HPBFs) ultrawi...

The active cooperation between a Primary User (PU) and a Cognitive User (CU) has the potential of leading to a transmission power reduction and transmission rate increase for both the PU and the CU. Alternatively, the required bandwidth may be reduced and the freed bandwidth may be leased to a group of CUs for their secondary communications. More explicitly, our cooperative protocol allows a CU...