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

This communication 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) comprises a checkerboard pattern of polarization conversion metasurface (PCM) 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 $2\lambda _{0} \times 2\lambda _{0} \times 0.09\lambda _{0}$ . Measured results show that the proposed antenna (PA) 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 x and y 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 PA’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.