Beamwidth enhancement of a circularly polarized microstrip antenna mounted on a three‐dimensional ground structure

Abstract
By mounting a regular circularly polarized microstrip antenna on a three‐dimensional (3‐D) square ground structure, beamwidth enhancement of the circular polarization (CP) radiation can be obtained. Experimental results show that, owing to the 3‐D square ground structure, the 3 dB beamwidth of the CP radiation can reach more than 110°, which is about 30° greater than that of a corresponding regular microstrip antenna. Details of the proposed 3‐D square ground structure are described, and the effects of various dimensions of the proposed square ground structure on the beamwidth enhancement of CP radiation are experimentally studied. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 149–153, 2002.