A Wideband Dual-Polarized Inductor-End Slot Antenna with Stable Beamwidth

This letter presents a wideband cross-slot antenna (CSA) with inductor loadings for dual polarization. The effects of the ground size on the impedance are investigated. To achieve a compact size, a very small ground having the same hypotenuse length as the slot is used. The inductor loadings are used at both ends of the slot to reduce the size further. Simulated results show that the loaded inductors contribute to a more constant impedance to the frequency response at 1-λ mode, and the impedance moves toward the lower frequency with inductors. Based on the constant impedance of the inductor-end slot at 1-λ mode, a dual-polarized CSA using two orthogonal slot radiators is designed. Measured results show that the proposed dual-polarized antenna has wide impedance bandwidths of 56.2% from 1.56 to 2.78 GHz and 60.6% from 1.46 to 2.73 GHz for Ports 1 and 2, respectively, with a high isolation of more than 26 dB over the operating bandwidth. The antenna also has a stable broadside gain of 8.05 ± 0.45 dBi and stable half-power beamwidths of 60.5° ± 1.8° in the E-plane and 76.1° ± 1.5° in the H-plane for Port 1.