Rectangular microstrip antenna for circular polarization

Richmond's reaction integral equation method is used to design a rectangular microstrip patch to produce a circular polarization. A rectangular patch with the aspect ratio a = W_{x}/W_{y} , in the range 1.015- 1.02 and corner fed by a microstrip line, produces circular polarization. For substrate with thickness d = 0.16 cm, a = 1.017 the nearly square patch gives maximum bandwidth.