A Wide-Band Metasurface for Asymmetric Microwave Transmission with Circular Polarization Conversion for Satellite Communications

Abstract

The polarization state control and manipulation of electromagnetic waves using chiral metasurfaces have various applications in satellite communications. The aspect of asymmetric transmission (AT) that allows a medium to pass the EM waves in one direction while having restriction in the opposite direction, adds an additional degree of freedom in order to facilitate one-way communication functionality. The proposed metasurface achieves linear to circular (LTC) polarization conversion with wideband AT functionality. This is accomplished for frequencies below 18 GHz using a bi-layered metasurface structure consisting of mutually twisted split ring resonators (SRRs). To achieve chirality, the proposed metasurface's top and bottom layers have a 90° rotation angle. For the frequency band of 13.34-13.83 GHz, the transmission goes up to − 4.3 dB. The maximum polarization extinction ratio (PER) of 45 dB has been achieved for the 490 MHz bandwidth at 13.5 GHz. The relatively simple structure, and the wide bandwidth enabled by using a bilayer metasurface, makes the proposed structure a promising design as a polarization controlling device that can be used in satellite communications.