A compact dual-circularly polarized cavity-backed ring-slot antenna

09 Feb 2017

A low profile dual-circularly polarized printed ring-slot antenna with a small footprint, which radiates above an open cavity loaded with an artificial magnetic conducting reflector, is presented. The feed network consists of two T-shaped capacitive feed structures connected to a miniaturized hybrid branch-line coupler. Experimental results for a final antenna design (with a size of 0.5λ0 × 0.5λ0 × 0.057λ0) show a 4% isolation bandwidth between the two ports of the dual-circularly polarized antenna and a maximum gain of approximately 6.8 dBic. Good front-to-back ratios and low cross-polarization were achieved. These very compact and low profile antennas are suitable for 2.4 GHz wireless local area network (WLAN) communication systems.