Directive antenna using metamaterial substrates

Abstract

Using a commercially available software(CST Microwave Studio®), two kinds of simulations have been carried out on different metamaterials in the microwave regime. One is transmission and reflection of a unit cell in a waveguide, and the other is parallel plate slab farfield radiation. The S-parameters are obtained from the wave-guide simulation and are used to retrieve the effective permittivity and permeability with which we can estimate the farfield radiation using analytic method. Thus, by comparing the farfield radiation from two different methods, analytic and slab simulation, we find that the analytic method is able to indicate many major features of the slab simulation's farfield results, implying that within a certain frequency range, we can treat the metamaterial as being homogeneous. After comparing the radiation performance of different metamaterial as antenna substrates, a structure is chosen to be optimized in such a way that it improves in radiation power, beamwidth, and bandwidth.