Compact dual-band circularly-polarised cavity-backed slot antenna

A compact dual-band and dual circular-polarisation cavity-backed slot antenna using the inverted configuration is presented. The proposed antenna consists of two subarrays providing left-hand circular-polarisation for the 12 GHz band and right-hand circular-polarisation for the 14 GHz band, respectively. The dual-band and dual-polarisation antenna is fed by a microstrip network printed on the top of the dielectric substrate (Rogers R/T Duroid 5880 substrate, with εr=2.2 and thickness of 0.127=mm), while a metallic cavity of a square shape is placed on the bottom side of the same substrate. With this simple arrangement, a compact design is realised for a dual-band circularly-polarised slot antenna. Details of the proposed antenna design are described and experimental results are presented.