Mutual Coupling on Axial Ratio of Circularly Polarized Antenna With Broadband Feed Network

Abstract

This paper presents a broadband feed network for dual-fed circularly polarized antenna. The feed network is composed of broadband 90° phase shifter and a Wilkson power splitter. The impedance bandwidth (VSWR≤ 2) is from 2.5 to 4.5 GHz (about 57%), with the 3 dB axial ratio bandwidth from 2.9 to 4.1 GHz, and the maximum gain are 7.0 dB at the center frequency. The simulated results in the 1×2 array shows that the mutual coupling deteriorates the axial ratio from 1.03 dB to 4.37 dB.