X-band directive single microstrip patch antenna using dielectric parasite

A new method to enhance the gain of a single microstrip patch antenna using spaced superstrates as a dielectric parasite is presented. The experimental results of radiation patterns using alumina parasites with different thicknesses and spacings are given. The minimum beamwidth obtainable with a single patch using present studies is only 18 degrees with symmetric lobes in the H and E planes. This simple method can also be used to vary the beamwidth of the patch between 18 and 125 degrees with proper choice of parasite parameters.