Circularly polarized stacked square patch microstrip antenna with tuning stubs

Abstract

Design and analysis of a single feed stacked square patch using tuning stubs is proposed which is capable in providing circular polarization along with broadband performance. The antenna is designed on glass epoxy FR-4 substrate with overall thickness of structure 9.18mm. The patch area of driven square patch is smaller than that of parasitic patch (truncated circular patch) to achieve improved performance. The center of both driven and stacked patches lays one over other. The location of feed point, amount of truncation of stacked circular patch and dimension and position of stubs are optimized to achieve circular polarization. The simulated axial ratio at two frequencies 2.3GHz and 2.66GHz are 1.61dBi and 0.45dBi respectively with an impedance bandwidth better than 16% is achieved with proposed geometry. The simulated E and H plane radiation patterns in entire impedance bandwidth are identical in shape and direction of maximum radiations is normal to patch geometry.