Wideband Circularly-Polarized Cavity-Backed Slot Antenna Array Using a Simplified 2×2 Subarray

A wideband circularly-polarized (CP) cavity-backed slot antenna array using a simplified sub array is proposed in this paper. Two pairs of degenerate modes are excited in a single cavity, and each pair of degenerate modes is used to produce a CP band. A pair of metal prisms is utilized to allocate the two bands close to each other, and a wider AR bandwidth can be obtained. The radiating slots are excited by the electric field of the cavity modes, thus, 2×2 radiating cross-slots can be placed on the top wall so as to form a CP array with a simplified structure. Then, a 4×4 array is designed using the 2×2 subarray via a I-to-4 cavity-based power divider. Final simulation shows that the proposed 4×4 CP slot antenna array can achieve 16% bandwidth with a peak gain of 16.8 dBic and a peak total efficiency of 99.5%.