Broadband RCS Reduction, Antenna Miniaturization, and Bandwidth Enhancement by Combining Reactive Impedance Surface and Polarization Conversion Metasurface

A metasurface (MS)-based low-profile, low radar cross section (RCS), wideband, and miniaturized microstrip patch array is proposed in this communication. First, a new method by combining reactive impedance surface (RIS) and polarization conversion metasurface (PCM) for antenna miniaturization and bandwidth enhancement as well as broadband RCS reduction is proposed. The proposed antenna is composed of a conventional patch antenna on top of an MS-based substrate. For the radiation performance, the antenna has a 10-dB impedance matching band of 22.3% and the overall volume is reduced to 78.9% after using the MS. For the scattering performance, broadband RCS reduction is achieved due to the polarization conversion characteristic of the MS. Over 10-dB RCS reduction is obtained from 6.10 to 18.90 GHz (a relative bandwidth of 106%). Second, the array composed of the $4\times 4$ element antennas and a feeding network is constructed and discussed. A 25.6% 10-dB impedance matching bandwidth and 106% 6-dB RCS reduction bandwidth are obtained. The overall size of the proposed array is reduced to 76% compared to the array without the MS. A prototype of the array was fabricated and measured. The measured results and the simulated ones are in good agreement. The proposed array by combining RIS and PCM has the advantages of wideband, miniaturized size, low RCS, and low profile, which can be used for radar, aircraft, and stealth platforms.