Efficient and automated generation of multidimensional design curves for coupled-resonator filters using system identification and metamodels

The design of coupled-resonator microwave band-pass filter is very often based on the physical implementation of a coupling matrix by correctly dimensioning the filter (geometrical) design parameters. An initial dimensioning is carried out using the design curves that describe the inter-resonator coupling parameter and external quality factor as a function of (geometrical) design parameters of a coupled-resonator pair and a single loaded resonator, respectively. These curves are usually generated using electromagnetic (EM) simulations. In order to minimize the number of EM simulations, these curves often consider only a single design parameter, while in reality several design parameters influence the inter-resonator coupling parameter and external quality factor. In this paper, a metamodeling method is used to generate multidimensional design curves with a minimal number of EM simulations, while maintaining a good accuracy. Moreover, their generation process is fully automated. The automated generation of multidimensional design curves for a coupled hairpin resonator filter validates the proposed method.