Wideband radar cross-section reduction of microstrip patch antenna using coding metasurface

This article proposes a design of a microstrip patch antenna with reduced radar cross-section (RCS) in a wide frequency band. The RCS of the patch antenna is reduced with the integration of an optimised coding metasurface. The coding metasurface is designed by placing artificial magnetic conductor (AMC) unit cells together to achieve a phase difference between 180 +/- 37 degrees within a wide frequency range. The out-of-band RCS for the proposed patch antenna is reduced >7 dB from 12.2 to 19.8 GHz, corresponding to a relative bandwidth of 48%, with a maximum reduction of 20 dB at 18 GHz. The operating frequency of the proposed antenna is 8.7 GHz and the RCS reduction is mainly in the Ku band. Both monostatic and bistatic RCS performance of the proposed patch antenna have been simulated and studied. The radiation performance of the proposed patch antenna is hardly influenced by the employment of the proposed coding metasurface. Details of the design considerations along with the simulation and measurement results are presented and discussed. The measured results are in a good agreement with the simulated ones, verifying the validity of the proposed antenna.