Radiation pattern direction control of THz antenna with applying planar graphene metasurface

Abstract

In this paper an antenna with dynamically controllable radiation pattern direction, in the low THz frequency band, is designed and investigated. The radiating element is composed of a rectangular patch antenna on a grounded dielectric while, radiation pattern control is made possible through applying a superstrate, inspired by metasurface structures, with gap of 25μm from the antenna surface. The radiating patch as well as the ground plane are designed with gold while the metasurface consists of graphene loops and patches which are placed on the either sides of a dielectric with the same material of the antenna substrate. Tunable radiation pattern direction is provided through activating appropriate columns of the metasurface unit cells. With applying an electrostatic bias voltage the graphene surface conductivity increases and the corresponding unit cells resemble properties of metals and impose parasitic effects on the antenna radiation pattern, which through wise selection of the metasurface unit cells the antenna radiation pattern is tilted in the desired direction. It is shown that the antenna radiation pattern can be dynamically controlled in the wide range of ±35degrees, symmetrically, in the H-plane.