Direct Use of the High Impedance Surface as an Antenna Without Dipole on Top

Abstract

High impedance surfaces (HISs) have been proposed and used as substrate for dipoles for realizing low-profile antennas. Here, we show that HISs can be used directly as low-profile antennas with a single feed point, without any dipole on top. The structure is made of only two metallic layers, the patterned surface and the ground plane below, at a subwavelength distance. We analyze two possible feeding mechanisms of an HIS made of dogbone-shaped conductors, though the ideas proposed here can be applied also to other HIS structures. We show that broadside gain of the order of 7-11 dBi can be obtained. We also explain that radiation of the HIS is in part related to a TM-like leaky wave with attenuation constant that is not as small in contrast to other standard high-gain leaky-wave antennas.