Green´s theorem modelling of overmoded coaxial waveguides

Electromagnetic boundary-value problems supported by closed-form solutions provide a framework for efficient and optimised design methods. Closed-form Green´s theorem models are used when a well-defined source is coupled to a well-defined space or structure. Here the Green´s theorem is applied to describe the relationship between the current in a coaxial probe and the electromagnetic fields inside an overmoded coaxial airspace. Several single-port boundary- value problems are illustrated before extending this to two-port problems with an application to a cavity filter. Each single and multi-port example is supported by experimental data that is in close agreement with the closed-form models in all cases.