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:
Dec. 26, 2000
Filed:
Apr. 09, 1998
Shun-ichi Seki, Amagasaki, JP;
Yutaka Taguchi, Takatsuki, JP;
Keiji Onishi, Settsu, JP;
Osamu Kawasaki, Kyotanabe, JP;
Kazuo Eda, Nara, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A resonator ladder type surface acoustic wave filter, has an input electrical terminal, an output electrical terminal, and a grounding terminal being formed on a piezoelectric substrate, a series arm surface acoustic wave resonator and a parallel arm surface acoustic wave resonator, each constructed from an interdigital transducer for exciting a surface acoustic wave, being formed between said input electrical terminal and said output electrical terminal, and when the center frequency of said resonator ladder type surface acoustic wave filter is denoted by fc, and capacitance determined by the number of electrode finger pairs and electrode finger overlap width in said interdigital transducer of said parallel arm surface acoustic wave resonator is denoted by Cp (fc: center frequency [GHz], Cp: capacitance of the interdigital transducer of the parallel arm surface acoustic wave resonator), capacitance C of multiples of said parallel arm surface acoustic wave resonator, connected to the same node between said input electrical terminal and said output electrical terminal, always satisfies the relation