Coupled resonator filter synthesis and design optimization for PCS wireless communications

This paper describes an efficient and robust approach for the computer-assisted design of coaxial filter structures. A circuit model transfer function obtained from a general 2-port network of synchronously tuned coupled cavities is used along with a multi-level optimization algorithm in order to obtain the coupling matrix of the filter. The resulting structure is fabricated and furthermore the frequency sampled-parameters are obtained from measurement. A model based parameter estimation procedure based on adaptive sampling is employed to approximate the frequency domain behavior of measured s-parameters in terms of rational functions. This approach can be applied to many classes of filters and is demonstrated through an application to a manufactured filter.