Dual-Band Dual-Circularly-Polarized Cavity Backed Antenna

Abstract

In this paper, we present a dual-band dual-circular polarized (CP) cavity backed 4×4 antenna array. This antenna can be used as a feeding antenna for Ka band satellite communication system. The operating center frequencies are 18GHz with RHCP and 28 GHz with LHCP. The required band width is 0.5 GHz. The proposed antenna element consists of a square cavity-backed structure with 4×4 radiating circular apertures. The feeding of this cavity-backed is a square aperture in the backside. The feeding network consists of two series of cavities fed by two orthogonal waveguide feeding networks. The upper feeding network is tuned at the lower frequency 18 GHz, while, the lower feeding network is tuned at the higher frequency 28 GHz. These antenna elements are supplied with using a rotating sequential feeding network. According to the direction of rotation and the sequential phase shift between the elements, it would be possible to obtain RH or LH circular polarization.