Metasurface Design for Circular Polarization Conversion via Asymmetric Transmission

Abstract

Metasurface gives you unprecedented control over the polarization, phase, and amplitude of electromagnetic (EM) waves. Because of its vital significance in diverse fields such as polarization conversion, antennas, satellite communication, radar cross section (RCS) reduction, microwave and optical communication and polarization manipulation property, metasurfaces has piqued the attention of researchers. Chiral metasurfaces are a type of metasurface in which the mirror copy of a structure cannot be overlaid on top of itself. Chirality in metasurfaces results in exceptional EM features such as polarization conversion and asymmetric transmission. Two separate designs for circular polarization converter chiral metasurfaces are presented in this thesis. By incorporating chirality into the structures, a reciprocal bi-layered metasurface can be created. The proposed designs are made of unique configurations of resonator structures (T, U and wires) on the top and bottom layers of the metasurface. To create chirality in the design, the identical structure is printed on the bottom layer as the top layer and then is rotated at a 90° angle. The suggested metasurface of design 1 can achieve asymmetric circular polarization conversion for x-polarization at lower frequencies of 5.52-5.59 GHz, 7.78-7.81GHz and 8.31-8.36GHz (C and X band). In the same way, design 2 is operating in K frequency band of range (18.5-18.9GHz and 22.9-23.2GHz.), for y-polarized incident wave. Furthermore, the response of these designs is unaffected by oblique incidences up to 45 degrees and thirty degrees for both design 1 and 2, respectively. The proposed metasurfaces are viable contenders for polarization conversion applications due to their simple designs, angular stability, lower frequency working bands, and minimized profile