A Miniaturized Circularly Polarized Yagi Antenna

A miniaturized circularly polarized (CP) Yagi antenna is proposed based on bowtie antenna array for satellite communication. The antenna is composed of six director elements, a driven element and a reflector element. The driven element consists of a pair of orthogonal bowtie antennas operating at 440 MHz, fed by an out-of-phase power splitter and 90 degree phase shifters to achieve circularly polarized radiation. Simulated results show that the antenna has a good CP performance over the frequency band from 435 to 445 MHz, with an axial ratio of 0.73 dB and a gain of 11 dBi at 440 MHz. The overall size of the antenna is 171×171×1105 mm3, the transverse size of the antenna is only about λ0/4 × λ0/4.