Compact High-Efficiency Broadband Metamaterial Polarizing Reflector at Microwave Frequencies

A compact highly efficient broadband microwave polarizing reflector, employing a quasi-2-D metamaterial composed of a single layer of square split-ring resonators, is presented and its performance is reported. Numerical and experimental results show a cross-polarization average polarization conversion ratio of greater than 90% for normal incident linearly polarized waves over a frequency range of 8.2-23 GHz. Due to multiple resonances occurring over this frequency range, the polarizing reflector presents both broadband performance and high polarization conversion efficiency. Transfer matrix and equivalent surface impedance theory and modeling are discussed to explain the physical underpinnings of the reflector's multiresonance behavior. These physical mechanisms are further analyzed by examination of simulated surface current distributions. The reflector is expected to be employed in applications where the control of the signal polarization is of central importance.