Optimization of performance of waveguides using the wave finite element method

A classical problem in the design of periodic waveguides is to get stop bands at desired frequencies. In this paper, the problem is addressed by use of optimization within the Wave Finite Element Method (WFEM). Typically, today optimization for stop bands is done using stochastic optimization due to the 'semi-discrete' behavior of the objective function. This method, in-line with previous work, is used as benchmark. This is compared to another method which handles the 'semi-discrete' behavior by a simple manipulation of the objective function into being continuous. This is a novel method that allows for fully gradient based optimization to be used. By comparing the continuous objective function with the benchmark method, it is found, that the continuous objective function outperforms the benchmark, in terms of computational speed and robustness.