Wideband and Low Cross-Polarization Transmitarray Using 1 Bit Magnetoelectric Dipole Elements

The application of magnetoelectric (ME) dipole to achieve wideband and low cross-polarization transmitarray design is presented in this article. First, a novel meandering-probe-fed ME dipole that exhibits a wideband matching, central feeding configuration, and symmetrical antenna structure is developed. These preferred features are borrowed to address the narrowband and potential element-displacement issues in 1 bit transmitarray element design. Numerical simulations of the proposed 1 bit ME-dipole transmitarray element show a wide 1 dB insertion-loss bandwidth of 47% and a low cross-polarization level of -40 dB. Measured results of the transmitarray designed using the proposed ME-dipole elements indicate an operating bandwidth of 47% and a cross-polarization discrimination (XPD) around 35 dB. In addition, a dual-layer phase compensation scheme for cross-polarization synthesis is described. The effectiveness of this method is demonstrated with a cross-polarization cancelation scheme that further improves the measured XPD to 40 dB. The proposed transmitarrays show advantages of remarkable bandwidth, low cross-polarization, and comparatively high aperture efficiency over most reported 1 bit designs.