Wideband balun filtering quasi‐Yagi antenna with high selectivity

Abstract

AbstractA compact wideband balun filtering quasi‐Yagi antenna with high selectivity is proposed. It consists of a quasi‐Yagi antenna integrated with a multilayer balun filter. The quasi‐Yagi antenna is composed of a bow‐tie driver coupled with a director on the top layer, and a ground reflector on the bottom layer. The fourth‐order balun filter has two stepped impedance resonators (SIRs) on the top layer, and two SIRs on the middle layer, which helps improve the frequency selectivity and bandwidth. Moreover, it has two differential ports to feed the quasi‐Yagi antenna. The filtering antenna centered at 2.5 GHz with a wide bandwidth of 22.8% and a pair of transmission zeros is designed and fabricated, which shows a stable radiation pattern with maximum gain of 5.5 dBi and high selectivity.