SURFACE ACOUSTIC WAVE RESONATOR

摘要

A surface acoustic wave resonator, comprises a piezoelectric substrate (10); a first surface acoustic wave resonator (22) having a first comb electrode (22a) provided on the piezoelectric substrate (10) and being designed to obtain a desired frequency characteristic by varying first overlapping lengths (L1) of the first comb electrode fingers; and a second surface acoustic wave resonator (21) having a second comb electrode (21a) provided on the piezoelectric substrate (10), being connected in parallel to the first surface acoustic wave resonator (22), and being designed to obtain a desired frequency characteristic by varying second overlapping lengths (L2) of the second comb electrode fingers smaller than the first overlapping lengths (L1) in order to differentiate the resonance frequencies in a transverse mode between the first and second surface acoustic wave resonator (22; 21), so as to separate spurious responses occurring within the passing frequency band due to standing waves developed in a direction orthogonal to the propagating direction, with the frequency of the spurious responses to the transverse mode resonances in the transverse mode being dependent upon the first and second overlapping lengths (L1; L2) of the first and second comb electrode (22a; 21a) fingers.