Stacked arrangement of modified hexagonal and square microstrip patches for broadband circularly polarized performance

This paper presents the radiation performance of stacked arrangement of a hexagonal patch antenna with a square patch antenna. Both antennas are prepared on glass epoxy FR-4 substrate and are separated through air gap. The simulation analysis is carried out by using method of moment based IE3D simulator. The optimization of side lengths, angles and applied air gap of proposed arrangement is carried out to achieve much improved bandwidth (30.2%) and circular polarization with significantly higher axial ratio bandwidth (15.2%). In the range of frequency where antenna is displaying broadband performance, the directivity and gain of proposed arrangement are much higher than that of a planar hexagonal patch antenna and are almost unchanged with variation in frequency. The radiation patterns obtained at two resonance frequencies are identical in shape with direction of maximum intensity normal to the patch geometry. The performance of this arrangement of patches is compared with that of a planar hexagonal patch antenna in free space.