摘要

This letter presents a compact dual-band, high-gain, light-weight, circularly polarized (CP) microstrip patch antenna with wide axial ratio (AR) beamwidth for multiple satellite communication, and positioning and navigation systems. The antenna consists of amain dual-frequency coplanarmetal frame radiator, a circular metal capacity-loaded radiator, and some coaxial feeding probes. Due to the use of air dielectric, the maximum right-hand circularly polarized gain of the antenna is up to 6.2 dBic in the lower bands and 6.3 dBic in the upper bands. By utilization of dual-frequency coplanar patch andmetal capacity-loaded technology, the dimensions of the aperture-shared CP antenna are only 0.38 lambda x 0.38 lambda x 0.04 lambda. To increase the 3 dB AR beamwidth, a novel vertically grounded shorting sheet is introduced. The 3 dB AR beamwidth ranges from -120 degrees to 100 degrees at 1.227 GHz and from -90 degrees to 95 degrees at 1.575 GHz. As a result, the proposed antenna is an excellent candidate for high gain, wide AR beamwidth, and compact air dielectric antenna.