A Metamaterial-Based Cross-Polarization Converter Characterized by Wideband and High Efficiency

Metamaterial-based polarization converters, which have all kinds of polarizations realizable via adjusting metamaterial parameters, have been springing up at an increasing rate. However, the reported metamaterial-based polarization converters suffer from either limited bandwidth or low polarization conversion ratios. In this study, a metamaterial-based polarization converter consisting of multilayer copper split-ring resonators and a copper ground separated by dielectrics was demonstrated and was characterized by the cross-polarization with wideband and high-efficiency. For normal incidence, the simulated results illustrated that the expanded bandwidth benefited from the superposition of cross-polarization electromagnetic resonances around 2.78, 3.09, 3.68, and 4.54 GHz, and the polarization conversion ratio was higher than 99% in the frequency range of 2.73 and 4.63 GHz. For oblique incidence, the design can provide larger angle tolerance in the investigated band, except for a very narrow stopband. Moreover, the experimental results agreed well with the simulations, which verified the reliability of the performance.