Optimization and Algorithm Quality Measure in the Design of Pill-Box Dielectric Window

The pill-box dielectric window is a key component in vacuum electron devices. Using the backtracking search algorithm (BSA) for its optimal design helps identify the precise design variables needed to achieve a desired frequency of 2.998 GHz and maximize bandwidth. The optimal design variables are a cavity length ( $C_{l}$ ) of 27 mm and a cavity radius ( $C_{r}$ ) of 33.3 mm. The pareto multi-objective backtracking search algorithm (PMBSA) algorithm’s performance was validated against well-known algorithms harmony search algorithm (HSA), multi-objective particle swarm optimization (MOPSO), and nondominated sorting genetic algorithm (NSGA-II). The quality of these algorithms was assessed using C-metric and spacing (SP) metric analyses, with the results presented in a box plot. Both the analyses suggest that PMBSA offers favorable results.