A low RCS microstrip patch antenna array using hybrid ground plane

A (2×2) microstrip patch antenna array (MSPAA) is designed at 10 GHz., for low radar cross section (RCS) outside the operating band of the antenna in the frequency band from 16 GHz. to 26 GHz. The conventional ground plane of the MSPAA is modified by using a hybrid ground plane comprising Jerusalem cross slot (JCS) frequency selective surface (FSS) elements in a square grid. The optimized gain of the antenna array is 13.38 dB with bandwidth of 6%. Superstrate effects are studied and the design is re-optimized for preserving the radiation properties of the antenna. Antenna radiation pattern measurements are carried out in microwave anechoic chamber to verify the design.