Electromagnetic modeling of complex uniaxial waveguide discontinuities using a modified MVM

In this paper, we extend the use of the multimodal variational method (MVM) to complex discontinuities. Classical MVM can´t be applied to characterize complex discontinuities because the modal basis of such complex discontinuities is very difficult to find. To surmount this deficiency, we divide the complex aperture into elements where the electromagnetic (EM) wave can be easily expanded into first order basis functions. Then, we assemble all basis functions to get the complete basis in the entire complex discontinuity. The modified MVM is applied to full-wave analysis of the computer aided design of complex irises. The results are validated with the HFSS simulations, the theoretical Marcuvitz and the experimental results.