A Compact, Broadband, Radar-Infrared Multispectral Stealth Antenna Based on Dual-Functional Polarization Conversion Metasurface

This paper presents a compact antenna which can realize broadband radar-infrared multispectral stealth. The antenna consists of a dual-layer structure: the top layer is an infrared shielding layer (IRSL) made up of periodically arranged square metal patches, while the bottom layer is a radar scattering layer (RSL) comprised of a checkerboard pattern of polarization conversion metasurface elements. The patch antenna is located in the central area of the RSL. At the central working frequency of 5 GHz, the overall dimensions of the antenna are 2×2×0.09λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub>. Measured results show that the proposed antenna operates within the 4.75-5.36 GHz band, achieving a maximum gain of 8.6 dB near 5.1 GHz. When the electromagnetic wave is vertically incident along the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> polarization directions, the radar cross section (RCS) reduction exceeds 8 dB within the 4.44-12.76 GHz frequency range (94.5%) and 10 dB within the 4.45-12.62 GHz frequency range (85.5%). Moreover, the proposed antenna’s average infrared emissivity is 0.21. Experimental results show that antenna can control radiative thermal effectively, leading to a significant decrease in the apparent temperature observed under a thermal imager.