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. 19, 2002
Filed:
Dec. 27, 2000
Fujitsu Media Devices Limited, Nagano, JP;
Abstract
The present invention provides a surface acoustic wave filter having an unbalance-to-balance conversion function and an impedance conversion function. This surface acoustic wave filter includes a piezoelectric substrate, a first surface acoustic wave filter that is made up of input and output interdigital transducers (IDTs), and a second surface acoustic wave filter that is also made up of input and output IDTs. The phase difference between the first surface acoustic wave filter and the second surface acoustic wave filter is approximately 180°. The input IDT of the first surface acoustic wave filter is connected to the input IDT of the second surface acoustic wave filter by a connecting wire, and a terminal extending from this connecting wire serves as an unbalanced terminal. An output terminal extends from the output IDTs of the first surface acoustic wave filter that are not connected to the second surface acoustic wave filter, and another output terminal extends from the output IDTS of the second surface acoustic wave filter that are not connected to the first surface acoustic wave filter. These output terminals constitute a balanced terminal