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:
Feb. 18, 1997
Filed:
Mar. 16, 1995
TDK Corporation, Tokyo, JP;
Abstract
A surface acoustic wave (SAW) device includes a plurality of SAW filters connected in cascade. An impedance matching element in the form of a SAW resonator is interposed between two adjoining SAW filters. Each filter includes a first piezoelectric substrate having a first electromechanical coupling factor and the resonator includes a second piezoelectric substrate having a second electromechanical coupling factor. The second electromechanical coupling factor is greater than the first factor so that the inductive band of the SAW resonator is wider than the pass band of the SAW filter. The device affords improved filter properties including an increased fractional bandwidth and an increased out-of-band attenuation.