Improved cross polarization and wideband multilayer wide-slot microstrip antenna with rotated parasitic patch

A single feed, compact and wideband microstrip patch antenna (MSPA) with high gain and low circular polarization is presented. The proposed antenna structure consists of two layers of the substrate. The lower or feeding substrate consists of an elliptical wide-slot and a 50 Ω microstrip line to excite this slot. The elliptical wide-slot generates two resonances, i.e. lower f
₁
(4.3 GHz) and higher f
₂
(7 GHz). An elliptical parasitic patch is placed on the upper or antenna substrate to improve the impedance bandwidth (IBW). A low cross-polarization (XP) is achieved by rotating the parasitic patch around its center. Simulation results show that the IBW for 10-dB return loss of 3.84-7.78 GHz (or 91.63%) is obtained. The antenna has the gain ranging from 6 dB to 11 dB. At f
₁
, minimum isolation of 34.63 dB in E-plane and 35 dB in H-plane and 33.69 dB in E-plane and 25.35 dB in H-plane for f
₂
is achieved. A stable and nearly omnidirectional radiation patterns are obtained for the given operating frequency range.