A Low-RCS and Wideband Circularly Polarized Array Antenna Co-Designed With a High-Performance AMC-FSS Radome

In this letter, we investigate a low radar cross-section (RCS) wideband circularly polarized microstrip array antenna co-designed with a high-performance artificial magnetic conductor and frequency selective surface (AMC-FSS) radome. Compared with the absorbent frequency selective radome-based antenna, the proposed co-designed antenna can achieve a relatively low gain loss in an extremely wide frequency range with wideband in-band and out-of-band RCS reduction, due to the introduction of a novel AMC-FSS radome which can achieve low insertion loss and wideband transmission by combining a double-layer miniaturized bandpass FSS and a single-layer chessboard AMC surface. We demonstrate the effectiveness of the proposed AMC-FSS radome and co-designed antenna through simulations and measurements. The results show that the gain deterioration of the co-designed antenna is only 0.42 dB at the central frequency of 4.8 GHz and less than 1 dB in the wide frequency band, ranging from 4.23 to 5.38 GHz with a relative bandwidth of 23.9%. At the same time, the monostatic RCS for a normal incidence is greatly reduced from 4 to 18 GHz.