Dual-mode acoustic surface wave filter

摘要

The filter has a number of dual-mode acoustic surface wave tracks, each of which has input and output transducers with a perpendicular finger structure, positioned between a pair of reflectors. The input transducers and the output transducers for all tracks are connected in parallel. The filter has a resonance structure providing a 4-pole characteristic. The filter may have two counter-phase tracks, respectively provided with a narrowband and a wideband characteristic, with both resonance poles of the narrowband track positioned between both resonance poles of the wideband track.