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:
Oct. 05, 1999
Filed:
Feb. 25, 1998
Applicant:
Inventors:
Hok Huor Ou, Tokyo, JP;
Naoto Inose, Tokyo, JP;
Assignee:
Oki Electric Industry Co., Ltd., Tokyo, JP;
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03H / ;
U.S. Cl.
CPC ...
333193 ; 333195 ;
Abstract
A SAW filter has SAW resonators coupled in a ladder network with at least one .pi.-type section. Besides having a series-arm SAW resonator and two shunt-art SAW resonators, the .pi.-type section has an inter-stage matching SAW resonator coupled in series with the series-arm SAW resonator. The inter-stage matching SAW resonator has an interdigital transducer with an electrode finger pitch substantially equal to the pitch in the series-arm SAW resonator. The inter-stage matching SAW resonator reduces impedance mismatching between the left half and the right half of the .pi.-type section.