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. 30, 2001
Filed:
Feb. 28, 2000
Yuki Satoh, Osaka, JP;
Toru Sakuragawa, Osaka, JP;
Mitsuhiro Furukawa, Osaka, JP;
Ryouichi Takayama, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The present invention relates to a surface acoustic wave filter used in frequency filter of portable telephone and other mobile communication device, and is intended to realize a surface acoustic wave filter capable of obtaining a stable filter characteristic even in the event of input of a large signal. The invention includes resonators (,) to (,) formed on a piezoelectric substrate (,), through-holes (,) provided near the resonators (,) to (,), and a conductive material (,) filling up the through-holes (,), in which the through-holes (,) filled up with the conductive material (,) are electrically grounded. In this constitution, by the through-holes (,) provided near the resonators (,) to (,) and filled up with the conductive material (,), the heat generated in the resonators (,) to (,) when a large signal is applied to the input terminal (,) can be released, so that a stable filter characteristic may be maintained if a large signal is applied.