Superstrate and CSRR Loaded Circularly Polarized Dual-Band Open-Ended Waveguide Antenna With Improved Radiation Characteristics and Polarization Reconfiguration Property

A circularly polarized dual-band open-ended waveguide (OEW) antenna, loaded with double complementary split-ring resonator (DCSRR) and superstrate, has been presented in this communication. The DCSRR has been placed on the aperture of a standard WR-90 waveguide, whereas the superstrate has been placed at an optimized distance from the aperture. Analysis and optimization have been carried out using Ansys high frequency structural simulator (HFSS) 14.0. Measured result shows two 10-dB return loss bandwidth with left-hand circular polarization. It has been shown that the antenna can be reconfigured for right-hand circular polarization by rotating the superstrate by 90°. The gain and front-to-back radiation ratio of the proposed antenna is higher than that of a conventional OEW antenna. It also provides less mutual coupling when used as an array element.