Gain enhancement in linear and circularly polarised microstrip patch antennas using shorted metallic patches

The influence of shorted metallic patches (SMPs) in the design of linear and circularly polarised microstrip patch antennas is investigated. The SMP structure consists of square patches connected to the ground plane by shorting pins. Effects of different parameters such as the dimension, and position of the SMPs on the performance of patch antennas are studied. It is shown that the implementation of the SMP in the patch design has led to significant improvements in gain and radiation patterns. The SMPs have also been incorporated in four element circularly polarised arrays to increase the gain and improve the axial ratio and impedance bandwidths. A comparison of the experimental results with simulation data demonstrates their good agreement.