A Wide-angle Low-scattering Microstrip Antenna

A new design method for wide-angle radar cross section (RCS) reduction for both co- and cross-polarizations is presented based on characteristic mode theory (CMT) and frequency selective surface (FSS). Taking the modal amplitude as the important mode selecting criterion, the important scattering and radiating modes are analyzed for a microstrip antenna. By cutting off the scattering modal currents, the wide-angle RCS reduction (RCSR) except the normal angle is obtained for co-polarization. Then, the FSS structure is used on the ground plane to reduce wide-angle RCS for cross-polarization and normal angular RCS for co-polarization. A wide-angle low-scattering microstrip antenna is achieved for both co- and cross-polarizations. For the co-polarization, it can realize RCSR from 0° to 90°, and the average and peak reductions are 6dB and 15 dB respectively. For the cross-polarization, it can realize low-RCS from 0° to 90°, and the average RCSR is 6dB. In the meantime, its transmission and radiation performances keep well.