An Efficient Analytical Method for Electromagnetic Field to Transmission Line Coupling Into a Rectangular Enclosure Excited by an Internal Source

A simple and efficient analytical method has been developed for predicting the electromagnetic field coupling with a lossless transmission line (TL) located in a rectangular enclosure. The metallic enclosure is excited by an internal electrical short dipole or monopole source. The electric fields generated inside the rectangular enclosure and excited by some simple sources are calculated by using the electric-type dyadic Green´s function. Our approach combines, on one hand, a lumped-pi circuit model of TL and, on the other hand, the Agrawal coupling model. A simple equivalent circuit has been derived which can give prediction for the coupling between the cavity field and the TL. This method is computationally less intensive compared to other numerical methods to solve such a problem. The analytical results have been successfully compared over a wide frequency band with the finite-difference time domain and experimental results carried out in different combinations of source and line position.