A Coupled Eigenmode Theory Applied to RF Structures

The purpose of the paper is to present a comprehensive analysis of the coupling mechanism between waves propagating in a periodic system of complex structure. The theory is developed in such a way as to utilize results from computer programs, based upon the finite-element method, to solve the two-dimensional eigenvalue problem. We first study a single system, simple enough to be considered as being characterized by two regions, for which the eigenmodes are all known. A matrix analysis is next developed and applied to an n-port circuit, representing the whole system considered as an assembly of subsystems such as studied first. An example is given for illustration. Theoretical results and measurements are compared.