High efficiency and ultra-wideband polarization converter based on an L-shaped metasurface

An ultra-wideband and efficient single layer polarization converting metasurface based on an L-shaped resonator is presented. The metasurface is based on an F4B dielectric substrate with relative permittivity of 2.65 and a loss tangent of 0.002. The size of the unit cell is 0.132 lambda(o) x 0.132 lambda(o) and the thickness of the metasurface is 0.05 lambda(o), where lambda(o) is the largest wavelength (corresponding to the lower frequency) in the operation band of interest. The proposed structure effectively transforms the linearly or circularly polarized incident wave to its orthogonal equivalent, which is justified by both simulated and measured results where the polarization conversion ratio (PCR) is greater than 90% in the frequency range from 8.6 GHz to 22 GHz with a fractional bandwidth of 88%. The polarization transformation process is illustrated in depth by the surface current distribution. Simulation results reveal that ultra-wideband is achieved because of strong electric and magnetic dipole resonances on the upper and the lower layer of the metasurface. Furthermore, the bandwidth and central frequency can be efficiently adjusted over a wide spectrum by changing the geometric aspects of the unit cell, thereby retaining high transformation proficiency. The designed converter can be used in applications such as antenna design, radar invisibility, imaging, microwave communications, and remote sensing. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

An ultra-wideband and efficient single layer polarization converting metasurface based on an L-shaped resonator is introduced. The metasurface efficiently transforms the linearly or circularly polarized incident wave, validated by simulation and measurement results showing a PCR greater than 90% in the frequency range from 8.6 GHz to 22 GHz.