Patent ID: 6369672
Filing Date: 2002-04-09
Classification: H03H

Abstract:
A surface acoustic wave filter comprising:at least one surface acoustic wave element including a piezoelectric substrate having at least one IDT, input/output terminals and reference potential terminals provided thereon, the input/output terminals and the reference potential terminals being connected to said at least one IDT; a package enclosing the at least one surface acoustic wave element, the package having electrode lands respectively connected to the input/output terminals and the reference potential terminals of the at least one surface acoustic wave element, further having external terminals connecting the electrode lands on the outer surface thereof; wherein said surface acoustic wave filter is adapted and arranged to be used in a superheterodyne system; and the resonance frequency of a resonator having the capacity of the at least one IDT of the at least one surface acoustic wave element and having inductances from the reference potential terminals of the at least one surface acoustic wave element to the external terminals of the package, is positioned in the vicinity of an image frequency occurring at the time of performing frequency conversion in the superheterodyne system.