A Novel Compact Six-Pole Filtering Gysel Combiner

This paper presents a novel two-way in-phase filtering Gysel splitter/combiner realized through a network of six-pole compact cross-coupled resonators. The network simultaneously realizes a filtering function and a two-way splitter/combiner function. Gysel combiners find application in high power amplifier designs. The five-port device uses a ring of six resonators arranged to realize, simultaneously, the combined filtering and coupling function. A rigorous coupling matrix describing the network is used to synthesize the integrated filtering and combining functions. This general network can be implemented in any of the available filter technologies. In this paper, compact combline coaxial resonators are employed and coupled using interconnected ridges to improve the bandwidth. The proposed design provides an integrated dual function module, reducing component counts and system complexity. A design was fabricated and tested demonstrating good results.