The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 09, 2001
Filed:
May. 11, 1999
Naoki Tanaka, Sakai, JP;
Sanyo Electric Co., Ltd., Moriguchi, JP;
Abstract
A surface acoustic wave filter of the transversely coupled mode resonator type including an interdigital electrode,having a plurality of electrode digits, and two reflectors,arranged, respectively, at opposite sides of the interdigital electrode,at a distance C from the electrode and each having a plurality of electrode digits. The filter has a pitch ratio of A/B, where A is the digit pitch of the interdigital electrode,and B is the digit pitch of each of the reflectors,The pitch ratio A/B and the distance C are determined such that on a two-dimensional coordinate system (X, Y) where the pitch ratio A/B is plotted as the Y-axis and a value C/&lgr; obtained by dividing the distance C by the wavelength &lgr; of surface acoustic waves is plotted as the X-axis, the pitch ratio A/B and the distance C are contained in a quadrilateral region having vertices at four points, i.e., point a (0.55, 0.983), point b (0.70, 1.010), point c (0.85, 1.010) and point d (0.85, 1.007), whereby the filter can be made more compact and is improved in characteristics outside the pass band.