A Filtering Quasi-Yagi Antenna with High Selectivity and Wide Stopband

A filtering quasi-Yagi antenna with high selectivity and wide stopband is proposed. To realize filtering function, a parallel absorptive branch, which composed by a bandstop filter and a resistor, is employed at the feed line to obtain absorptive type radiation nulls on the both stopbands to improve the out-of-band suppression level and the width of stopband. Directors are employed symmetrically to improve the gain. According to the simulation results, the bandwidth of proposed antenna is 9% (2.52 to 2.75 GHz), and the realized gain is from 8.6 to 9.3 dBi. High out-of-band suppression and low sidelobes level are achieved with 15 and -14 dB.