A 30GHz high-gain circularly-polarized pattem-steerable antenna based on parasitic patches

This paper represents an aperture-coupled circularly polarized (CP) microstrip patch antenna with four parasitic elements around the radiating patch. Four parasitic elements are applied to improve the antenna directivity. In order to generate CP electromagnetic wave, a cross-shaped slot is etched off the patch's metal ground surface. The beam reconfiguration is obtained using the metal shorting p-i-n diodes, which is placed between the parasitic elements and the planar ground. To further enhance the antenna gain and CP bandwidth, the paper also presents simulated results for an antenna array based on parallel sequential feeding technique.