Ultra wide band radar cross section reduction using multilayer artificial magnetic conductor metasurface

A new thin planar wideband radar cross section (RCS) surface is designed and fabricated by using two different artificial magnetic conductor (AMC) unit cells. These AMC unit cells are designed by both substrate height and relative permittivity variations to achieve an ultra wide bandwidth performance. Three layer low cost FR-4 substrates are used to simply implement these unit cells. The proposed structure reduces the RCS more than 10 dB from 13.1 GHz to 44.5 GHz (109% bandwidth), more than 20 dB from 16.43 GHz to 42.31 GHz (88.3%), and more than 30 dB from 24.7 GHz to 40.9 GHz (49.4%). Moreover, this surface has more than 103% RCS reduction bandwidth for TE polarized and more than 93% for TM polarized ones up to 50° oblique incident waves. The good agreement between the simulation and measurement results also prove the idea. In addition to using a low cost substrate, the proposed surface has a significant widest RCS reduction bandwidth compared with the state of the art references in the normal and oblique incident angles at both TE and TM polarizations. (paper)