New dimension in cross-polarization reduction of a hexagonal microstrip antenna using two circular substrate integrated cavities

Novel application of Substrate Integrated Cavity (SIC) for suppressing cross-polarized (XP) radiation in hexagonal microstrip antenna has been proposed. The proposed design consists of a pair of tiny circular SICs consisting of metallic vias located symmetrically on the H-plane of the hexagonal patch. The design has been simulated in Ansys HFSS
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to establish the proposition that the incorporation of SIC does not affect the fundamental mode of resonance and the co-polarized radiation levels of the conventional antenna considerably but effectively reduces the cross-polarization radiation levels. An isolation of -81 dB of cross-polarization level from its peak has been obtained at the boresight of the patch. Compared to the conventional hexagonal patch, a relative suppression in cross-polarization of 49 dB at the boresight and 15 dB throughout in both the principal planes has been achieved.