Directivity enhancement of microstrip antennas using dielectric superstrates

The subject of directivity enhancement of microstrip patch antennas (MPAs), using either a Frequency Selective Surface (FSS) or a double-negative (DNG) metamaterial slab, has been investigated by a number of researchers in recent years. The purpose of this paper is to show that we can also achieve the same goal by using a much simpler design for the superstrate, namely a dielectric slab, whose performance can comparable, and even be superior to those of the other two typical choices for the superstrate, namely the FSS or the DNG.