Computer aided design and structural optimization for microwave components

This article describes the development of a library of computer-aided-design (CAD) optimization techniques for advanced design of microwave components. The microwave components are modeled by finite elements and their dimensions and shape are optimized using four methods: design of experiments (DoE), level-set method (LS), topology gradient method (TG) and genetic algorithm (GA). The various techniques allow determining the optimal geometry, shape or topology of 2D or 3D objects within the component, by minimizing iteratively a cost function related to desired specifications. These global and local optimization methods are coupled together resulting in an optimization library where the various techniques can be selected successively in order to acquire a much better result compared to methods applied solely. The approach is illustrated by the design of dielectric resonators with improved unloaded quality factor.