Circularly polarized SIW antenna array based on sequential rotation feeding

Abstract

A right-handed circularly polarized (CP) substrate integrated waveguide (SIW)-based square ring-slot antenna array is proposed in this study. The array is composed of four elements and is based on a sequential rotation feeding technique to achieve wideband circularly polarization performance and high polarization purity. The feeding network for the array adopts SIW power divider having phase delay characteristic. In order to validate our design method, the antenna array is fabricated and measured. The measured impedance and axial ratio (AR) bandwidths are 8.5% (VSWR<2) and 6.1% (AR<3 dB), respectively, whereas the impedance and AR bandwidths for the element are 6.5% and 1.5%. It can be observed that this technique has significantly enhanced the AR bandwidth. Moreover, the antenna has a stable CP peak gain more than 12 dBi from 9.15 GHz to 9.5 GHz.