Calculation of Spectral Green’s Function and Its Asymptotical Behavior for Sheet Electric Current in Two-Layer Dielectric Waveguide

Structures with patches placed on the interfaces in a two-layered dielectric waveguide are promising to be used in different applications at THz waves. To realize the method of moments (MoM) solution in the spectral domain spectral Green’s functions (GFs) for sheet electric currents on the interfaces of the two-layer dielectric cylindrical waveguide are needed. This paper presents the way to enhance the MoM solution efficiency by extracting an asymptotic behavior of the spectral GF which depends on two variables: the propagation constant and the azimuth index. Here asymptotic spectral GFs are constructed and calculated when electrical sheet current is placed on different interfaces.