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:
Nov. 24, 2009
Filed:
Dec. 06, 2007
Hajime Kando, Ritto, JP;
Norihiko Nakahashi, Ishikawa-gun, JP;
Teruhisa Shibahara, Kyoto, JP;
Murata Manufacturing Co., Ltd., Kyoto, JP;
Abstract
A boundary acoustic wave filter device capable of increasing an out-of-band attenuation includes a dielectric film formed on a piezoelectric substrate, at least one longitudinally coupled resonator boundary acoustic wave filter having a plurality of IDTs disposed along a boundary between the piezoelectric substrate and the dielectric film, and at least two one-terminal-pair boundary acoustic wave resonators. At least one boundary acoustic wave resonator is connected in series to the longitudinally coupled resonator boundary acoustic wave filter, and at least remaining one boundary acoustic wave resonator is connected in parallel to the longitudinally coupled resonator boundary acoustic wave filter. An anti-resonant frequency of the serially connected boundary acoustic wave resonator is located in a higher frequency range than a passband of the boundary acoustic wave filter device, and a resonant frequency of the parallel-connected boundary acoustic wave resonator is equal to or higher than the anti-resonant frequency of the serially connected boundary acoustic wave resonator.