Ultra-wideband polarization conversion metasurface at microwave frequencies

Abstract

We propose an ultra-wideband polarization-conversion metasurface using a rectangular split-ring resonator (SRR) with two splits. The metasurface is numerically designed on an FR4 dielectric substrate backed by a metallic ground plane. The broadband characteristic is optimized by the genetic optimization algorithm, from which the unit cell generates a 3 dB fractional bandwidth from 5.45-15.46 GHz. This wideband polarization conversion results from multiple plasmonic resonances occurring at three neighboring frequencies (6.736, 7.367, and 13.716 GHz), and polarization conversion efficiency reaches 100% at three plasmon resonances. Owing to the sub- wavelength unit cell size and the rectangular SRRs, the response of the metasurface is independent of the polarization and incidence angle of the incoming wave, which show great practical application value and practical application prospects in optoelectronic devices, remote sensing, communication, and detection.