Ultra-wideband RCS reduction of microstrip antenna array by optimised multi-element metasurface

A microstrip antenna array (MAA) loading with metasurface is designed and fabricated for ultra-wideband radar cross-section (RCS) reduction while preserving its radiation characteristics. A new physical mechanism based on size adjustment of the multiple basic unit cells is proposed for ultra-wideband manipulation of electromagnetic waves. To obtain the excellent RCS performance, the selection of the basic unit cells is optimised by the hybrid optimisation algorithm. Both simulated and measured results indicate that the proposed MAA can reduce the RCS significantly in an ultra-wide frequency band from 6.2 to 27.3 GHz under x- and y-polarised normal incidence. The radiation characteristics of the MAA are well preserved simultaneously.