A slotted circularly polarized semicylindrical conformal patch antenna for EBS and BRS bands

Abstract

A circularly polarized semicylindrical patch antenna loaded with unequal slots for use in S-band applications is presented and designed. Circular polarization operation is demonstrated for both planar and semicylindrical structures by embedding four quarter-circular slots with asymmetric radius at the four corners and two symmetric semicircular slots on both side edges. An axial ratio (AR) bandwidth of 50 MHz and a return loss band width of 210 MHz are achieved with the planar structure. The 3-dB AR beam widths obtained in the E and H plane are 85° and 65°, respectively, at a frequency of 2.5 GHz for the planar patch. The semicylindrical antenna exhibits a beam width of 66.9° in the E plane and 113° in the H plane. For the semicylindrical antenna, a 3-dB axial ratio bandwidth of around 59 MHz and a −10 dB return loss bandwidth of 214 MHz with a uniform directive gain of 7.04 dB in the pass band are also achieved.