Ultra Wideband Low-RCS Linear Polarised Array Based on Composite Metasurface

Abstract

This paper proposed the design of an ultra-wideband antenna array with low radar cross section (RCS) based on a composite metasurface. In the high-frequency region, an ultra-wideband polarisation conversion metasurface (PCM) unit is designed. Under normal incident wave illumination, a pair of mirrored PCM units operate in anti-phase, effectively achieving radar cross section reduction (RCSR). In the lower frequency region, a corner-cut square patch is introduced, which generates an approximate $180°$ phase shift relative to the PCM unit, enabling RCSR through phase cancellation. These corner-cutted square patches simultaneously serve as antenna radiators, thereby simplifying the design and reducing structural complexity. Simulation results demonstrate that the metasurface-excited antenna array operates within a frequency range of 10$\sim$11.5 GHz, achieving a peak gain of 12.5 dBi. The in-band and out-of-band RCSR bandwidth reaches 125.6%. Compared with the reference antenna and reference metasurfaces composed of a single type of unit, the proposed antenna not only broadens the RCSR bandwidth but also enhances the RCSR performance. Finally, the fabricated antenna is measured, and the measured results align well with the simulations, confirming the proposed design's effectiveness, antenna array, metasurface, radar cross section, ultra-wideband, and phase cancellation.