Abstract
Compact fifth-generation (5G) low-frequency band filtering antennas (filtennas) with stable directive radiation patterns, improved bandwidth (BW), and gain are designed, fabricated, and tested in this research. The proposed filtennas are achieved by combining the predesigned compact 5G (5.975 - 7.125 GHz) third-order uniform and non-uniform transmission line hairpin bandpass filters (UTL and NTL HPBFs) with the compact ultrawide band Vivaldi tapered slot antenna (UWB VTSA) in one module. The objective of this integration is to enhance the performance of 5.975 - 7.125 GHz filtennas which will be suitable for modern mobile communication applications by exploiting the benefits of UWB VTSA. Based on NTL HPBF, more space is provided to add the direct current (DC) biassing circuits in cognitive radio networks (CRNs) for frequency reconfigurable applications. To overcome the mismatch between HPBFs and VTSA, detailed parametric studies are presented. Computer simulation technology (CST) software is used for the simulation in this study. Good measured S11 appeared to be < -13 and < -10.54 dB at 5.48 - 7.73 and 5.9 - 7.98 GHz with peak realized gains of 6.37 and 6.27 dBi, for VTSA with UTL and NTL HPBFs, respectively which outperforms the predesigned filters. Validation is carried out by comparing the measured and simulated results.