Patent ID: 6049260
Filing Date: 2000-04-11
Classification: H03H

Abstract:
A surface acoustic wave filter comprising:Inter Digital Transducers (IDTs) on an input side and on an output side each including a plurality of pairs of electrode digits, said IDTs being formed on a piezoelectric substrate with a spacing interposed therebetween,wherein N.epsilon..gtoreq.0.55 is satisfied where .epsilon. is a reflection coefficient of the electrode digit and N is the total number of the pairs of the electrode digits constituting said IDTs on the input side and on the output side, andwherein fH.ltoreq.-17.5W+210 is satisfied where W.lambda. is an aperture width of a surface acoustic wave transmission path formed of said IDTs on the input side and on the output side, f in units of Hertz is the center frequency of said filter, and H in units of meters is the thickness of the electrode digits.