Design of wideband small microstrip antenna with circular polarization

Abstract

The theoretical results of a small wideband microstrip antenna are presented and discussed. Due to the delay of fabrication by the industry in Mainland, it was regret that the experimental results of the antenna cannot be shown in this project. The aim of this project is to design and fabricate a small wideband mircorstrip antenna with circular polarization. In order to overcome the problem of narrow impedance bandwidth for microstrip antennas, a relatively thick substrate with dielectric constant equal to 20 is used in the fabrication of this antenna. However, due to the increase in the thickness of the antenna, the substrate layer acts like an inductor inside the antenna, which causes difficult to achieve a good impedance matching. Another method to widen the bandwidth is to cut a U-slot on the patch of the antenna. Before starting the antenna design, a parameters study has been done in this project to investigate the effect of the U-shaped aperture. Also, comparisons of simulated results with the conventional antennas are also presented in this project.