Dual-band microstrip-fed cavity-backed slot array of circular polarization

A compact design for dual-band dual-sense circularly-polarized cavity-backed slot (CBS) array is described in this paper. The presented CBS antenna exhibits a dual frequency band of operation for two orthogonal circular polarizations. Using the sequential rotation method of feeding the array elements, the larger subarray operates at 12 GHz and produces left-hand circular polarization, while the smaller subarray operates at 14 GHz and radiates right-hand circularly polarized waves. The measured 10-dB return loss bandwidth of the slot array is 16.2% for 12 GHz band and 20.5% for 14 GHz band, respectively. The measured gains are 10.19 dB at 12 GHz and 7.93 dB at 14 GHz.