A novel trust‐region–based algorithm with flexible Jacobian updates for expedited optimization of high‐frequency structures

Abstract

Simulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure's geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially important in the case of complex and multiparameter structures. In the paper, an expedited trustregion-based algorithm for electromagnetic (EM)-driven design optimization of high-frequency structures is proposed. The presented technique involves a flexible sensitivity update scheme depending on the relative design changes with respect to the trust-region size, as well as a direction of the design relocation and its alignment with the coordinate system axes. This allows for performing finite-differentiation-based sensitivity updates less frequently and, consequently, brings considerable computational savings. Numerical results obtained for an ultra-wideband antenna and a microwave coupler demonstrate that the proposed algorithm outperforms the reference procedure in terms of the number of EM simulations necessary to arrive at the optimized solution (around 50%). At the same time, the design quality loss is minor. KEYWORDSantenna design, Broyden update, electromagnetic simulation-driven design, microwave design closure, trust-region framework