Surface acoustic wave filter.

摘要

SAW filter (21) formed by arranging a plurality of IDTs (23 to 29) on a piezoelectric substrate (22) along a surface wave propagation direction, at least a single one-port SAW resonator (30) being connected in parallel with an output side of the SAW filter, while the resonance frequency (f0) of the SAW resonator (30) being set in frequency region level which is lower than the pass band of the SAW filter.