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. 21, 2003
Filed:
Feb. 20, 2002
Masao Gamo, Takaoka, JP;
Murata Manufacturing Co., Ltd., Kyoto, JP;
Abstract
A piezoelectric filter includes first and second dual-mode filter elements connected in a face-to-face arrangement. The first and second filter elements have substantially the same center frequency. Each of the first and second filter elements has a piezoelectric substrate, which has unpolarized sections located at edges thereof. Portions of a vibration region where energy-trapped vibration of each of the first and second filter elements is generated are located in the unpolarized sections. The ratio of the area of the portions of the vibration region which are located in the unpolarized sections of the first filter element to the area of the entire vibration region of the first filter element is different from the ratio of the area of the portions of the vibration region which are located in the unpolarized sections of the second filter element to the area of the entire vibration region of the second filter element.