Novel Implementations for Microstrip Resonator Filters in Transversal and Alternative Topologies

This paper presents novel and compact implementations of microstrip filters using transversal topologies. The structures proposed are based on source/load-multiresonator coupling, and implement different topologies, allowing the synthesis of different frequency responses with transmission zeros for maximum selectivity. Design guidelines for different resonator topologies are also reported to show the possibilities of the proposed structures. The analyzed characteristics of these filters, obtained with commercial full-wave computer-aided tools, show excellent agreement with synthesis results. Several filter prototypes of third order, showing different frequency responses, are manufactured and tested, obtaining good agreement with theoretical predictions.