High-Gain Dual-Band Aperture-Shared CP Patch Antenna With Wide AR Beamwidth for Satellite Navigation System

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 a main dual-frequency coplanar metal 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 and metal capacity-loaded technology, the dimensions of the aperture-shared CP antenna are only 0.38λ × 0.38λ × 0.04λ. To increase the 3 dB AR beamwidth, a novel vertically grounded shorting sheet is introduced. The 3 dB AR beamwidth ranges from −120° to 100° at 1.227 GHz and from −90° to 95° 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.