A High Gain CP Antenna with Extreme Radiation Aperture for Vehicle Applications

Abstract

A high gain circularly polarized (CP) antenna with extreme radiation aperture in vehicle applications is proposed in the paper. The coverage of the radiation patch extended to the whole side of the dielectric substrate realizes the extreme radiation aperture, which can increase the utilization ratio of antenna aperture maximally. Besides, Taking advantage of the radiation from the side patch, and the application environment, the roof of the vehicle which is a great metal reflector beneath the antenna, wide beamwidth can be realized. A distinctive 90° phase difference feed network located beneath the ground plane and four symmetric feed probes via the dielectric substrate form the feed structure. Good circular polarization radiation performance and impedance matching are achieved by adjusting the design of the feed network and the position of the probes, that is the feed points. The antenna works at around 1.48 GHz to receive satellite signals, especially for vehicle satellite signal reception. Experimental results show that it has a high gain above 7 dB in the required range when put on the roof of the car. The overall size of the antenna is $0.247\boldsymbol{\lambda}_{0}\times 0.247\boldsymbol{\lambda}_{0}\times 0.247\boldsymbol{\lambda}_{0}$ at 1.48 GHz.