Accurate modal decomposition of the multimode high power microwave output using blind optimization

In this paper, a new approach for the complete modal decomposition of the electric fields emerging from the overmoded high power microwave devices is presented. Based on the simultaneous perturbation stochastic approximation (SPSA) algorithm, mode coefficients of the multimode high power microwave both in interaction region and the output window can be exactly calculated utilizing the field intensity distribution of the electric field. Numerical simulation validates the feasibility and the average reconstruction error is around 0.5%. With this method, mode analysis becomes possible and effective, which is very significant in the development of the high power microwave devices with overmoded slow wave structures, especially for high frequency generation.