Waveguide slot antenna using high-impedance surface

High-impedance surface (HIS) is a kind of electromagnetic bandgap (EBG) structure utilized as a ground plane for two waveguide slot antennas in order to improve their radiation characteristics. As compared to a solid metal ground plane, the results suggest that a high-impedance ground plane (HIGP) can significantly improve the patterns of the slot antennas. The ripples in the E-plane patterns of the slot antennas with a metal ground plane are found to vanish, the back lobes are reduced, and the gains are increased.