Generation of Admissible Grid Topologies for Coupled-Resonator Filters

This work introduces an algorithm for the generation of admissible grid topologies for coupled-resonator microwave filters, capable of introducing a high number of transmission zeros in the filter response (for a given number of resonators). Both regular and frequency-dependent couplings are allowed in the generated topologies. This algorithm is used to create regular grid topologies with various shapes, e.g. rectangular, triangular, diamond…. The exhaustive synthesis of the generated topologies is carried out through a numerical procedure recently introduced. Several synthesis examples are reported in the paper to validate the proposed algorithm.