Broadband Circularly Polarized H-Shaped Patch Antenna Using Reactive Impedance Surface

A compact, single-feed, broadband circularly polarized patch antenna is proposed in this letter. The antenna comprises an H-shaped microstrip patch printed over a metamaterial-inspired reactive impedance surface (RIS). The RIS structure comprising a lattice of 4 × 4 periodic metallic square patches helps to increase the bandwidth of the antenna. The final optimized structure exhibits an impedance bandwidth of 44.5% (4.64-7.3 GHz) along with a 3 dB axial-ratio bandwidth of 27.5% (4.55-6 GHz). Moreover, the proposed antenna yields a good broadside gain of 7.2 dBi at 5.5 GHz. The radiation efficiency of the present structure is better than 77% for the entire band of operation.