Dual-band high-gain shared-aperture antenna with large frequency ratio hybridizing Fabry-Perot cavity and folded transmitarray

Abstract

A novel dual-band high-gain shared-aperture antenna with a large frequency ratio is proposed in this letter. This antenna consists of two layers. Based on the different electromagnetic characteristics at two bands, these two layers can be used to form an Fabry-Perot cavity antenna (FPCA) in the microwave band and an folded transmitarray (FTA) in the millimeter-wave band. By integrating the FPCA into the FTA, we achieve a large frequency ratio of 8.6. A novel feed configuration with a horn in the center and a patch array along the edge is designed. Through the feed configuration based on FPCA and FTA, our shared-aperture antenna achieves higher aperture efficiency at dual bands compared with other similar works. An antenna prototype operating at both 3.5GHz and 30GHz bands is designed, fabricated and measured. Measurements show that the peak realized gain is 11.9dBi at 3.5GHz and 26.2dBi at 30GHz, respectively. The aperture efficiency can reach to 82% at the S band and 30% at the Ka band.