RCS Reduction of 2×2 Microstrip Antenna Array Using All Dielectric Metasurface

Abstract

This paper proposes a method to reduce the radar cross section (RCS) of a 2×2 microstrip antenna array around 20 GHz. The presented design is based on reflection phase cancellation principle and uses an all dielectric unit cell. Two perforated unit cells with 0° and 180° reflection phases are used and their geometrical parameters are optimized carefully to have 180° ± 30° reflection phase difference between their reflection phases, which is required to realize the phase cancellation. A 2×2 microstrip array is designed at 20 GHz and the proposed unit cell is distributed around the antennas in Chessboard like surface. A clear monostatic RCS reduction is achieved from about 18 GHz to 27 GHz with low level backscattered EM wave in the half space in front of the antenna array under both normal and oblique incidence of far-field plane wave. In the presented technique, no metallic inclusions are used on the upper surface of the dielectric substrate next to the antenna array radiating elements. Compared to the previously published works which used metallic inclusions next to radiating elements, the presented design has less effect on the radiation characteristics of the antenna array.