Numerical analysis of discontinuities in a rectangular waveguide loaded with isotropic or anisotropic obstacles by means of the coupled‐mode method and the mode‐matching method

Abstract

SUMMARYA hybrid method obtained as a combination of the coupled-mode method (CMM) and the mode-matching method (MMM) is developed and applied in the analysis of multiple dielectric and magnetic discontinuities in rectangular waveguides. As both are moment methods, some kind of truncation has to be carried out in the computer implementation. It is shown that selection of a different number of modes in the two methods is not necessary, unless low-permittivity media inside the waveguide are considered. As a consequence, the procedure for selecting the number of basis functions is only done in one of the methods. Numerical examples are presented showing the behaviour of the method and the proofs of convergence. Examples are included illustrating the power of this hybrid technique, especially in relation to non-reciprocal structures containing magnetized ferrites.

A brief discussion on the different formulations of the coupled mode method in chiral media: Application to the parallel‐plate chirowaveguide

“…(1)] is not correct, because a term independent of the transverse coordinates is not included. For magnetic media, it has been proved [8] that the absence of this term produces incorrect results, both in the propagation constants and in the electromagnetic field. The same occurs for bi-isotropic media [4].…”

Improving the coupled‐mode method by means of step functions: Application to partial‐height isotropic or anisotropic dielectric parallel‐plate waveguides

“…In the same manner, the longitudinal components of the electromagnetic field can be expressed as [6] …”

“…In the present case, the constitutive relations for the slab of ferrite magnetized to saturation in the y direction are [10] From this point on, the process can be seen in detail, for a rectangular waveguide, in [6], with the only change being the expansion for the E y component. Thus, the eigenvalue system obtained is where the expressions for the matrices are shown in Appendix 1.…”

“…Moreover, this method can easily be combined with the modematching method to characterize discontinuities, which results in considerable numerical benefits [6,7]. Its main advantage is its versatility, because it is not necessary to apply boundary conditions to the dielectric interfaces.…”

On One- and Two-Dimensional Electromagnetic Band Gap Structures in Rectangular Waveguides at Microwave Frequencies

“…This method has been applied to uniform waveguides partially filled with different types of materials (Solano, Vegas, & Prieto, 1995). Downloaded by [Florida International University] at 08:36 03 January 2015 Figure 14.…”