Ultra-Wideband RCS Reduction and Gain Enhancement of Aperture-Coupled Antenna Based on Hybrid-FSS

Abstract

A novel design of aperture-coupled microstrip antenna with ultra-wideband low radar cross section (RCS) is proposed. Hybrid frequency selective surface (FSS) structures consisting of two kinds of polarization-dependent folded split ring resonators (PDFSRRs) and square patches are utilized to replace the conventional metallic ground. By orthogonally arranging the PDFSRRs in a chessboard-like configuration, the band-stop characteristic contributes to the gain enhancement, while the zero degree points of reflection phase and wave-transmission characteristic are utilized to achieve RCS reduction both in-band and out-of-band. Furthermore, with square patches periodically etched on the bottom of FSS structure, a new zero degree reflection phase is introduced to enhance the effect of RCS reduction. Full wave simulations and measurements demonstrate that the proposed antenna achieves RCS reduction from 1 GHz to 18 GHz and gain enhancement compared with traditional microstrip antenna.