Effect of Anisotropic Metasurface Linings on Circular Waveguide

The rapid development of metasurfaces has become a new momentum driving novel electromagnetic applications. When they were loaded inside circular waveguides as linings, many intriguing phenomena were observed. From the point view of the surface impedance of a lining, the real part of the impedance, or called surface resistance, induces attenuation effect to the waves propagating through the waveguide, and the imaginary part, or surface reactance, causes shifts to the dispersion of the waves. Some literatures have discussed the effects of the surface impedance, but most of them involved isotropic conditions only. In this paper, dispersion and attenuation characteristics of the waveguides affected by anisotropic metasurface linings are analyzed through mathematical derivations and numerical validations, and new approaches are proposed for predicting the performances. This work may pave a way for new applications in circular waveguides, such as single-mode bandwidth expansion, degenerate mode avoidance, mode filters, and so on.