RCS Reduction of a Patch Array Antenna Based on Microstrip Resonators

Microstrip resonators are used for reducing the in-band monostatic radar cross section (RCS) of a patch array antenna. The reference patch array antenna works at 4.5 GHz, and the proposed antenna with microstrip resonators is designed at the same frequency. The resonant frequency of the microstrip resonators is also 4.5 GHz so that it can cover the operating band of the patch array antenna. Compared to the reference antenna, which does not have the microstrip resonators, the simulation results demonstrate that the monostatic RCS of the proposed array antenna can be reduced at least 10 dB for both phi- and theta-polarized incident waves while preserving the desired radiation characteristics. Measurements on realized prototypes show good agreement with the simulations and prove the reliability and superior performance of the proposed approach.