Derivative-free microwave design optimisation using shape-preserving response prediction and space mapping

A two-level derivative-free algorithm for electromagnetic-simulation-driven design optimisation is introduced. The technique exploits a fast surrogate model that is created using a modified version of a shape-preserving response prediction (SPRP) methodology and a limited amount of coarse-discretisation electromagnetic (EM) simulation data. The surrogate is subsequently utilised by the space mapping algorithm to find a design satisfying given performance specifications. As demonstrated using two examples of microstrip filters and a planar antenna, the design cost is low and corresponds to a few high-fidelity EM simulations of the optimised structure and it is 30-50% lower than that for the original SPRP technique exploiting coarse-discretisation EM models.