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:
Mar. 23, 2004
Filed:
Jan. 14, 2002
Masaru Yata, Ishikawa-ken, JP;
Kazunobu Shimoe, Kanazawa, JP;
Yoichi Sawada, Ishikawa-ken, JP;
Hiroki Watanabe, Ishikawa-ken, JP;
Yuichi Takamine, Kanazawa, JP;
Murata Manufacturing Co., Ltd., Kyoto, JP;
Abstract
A surface acoustic wave filter device has a balance-unbalance conversion function and substantially equal input impedance and output impedance so as to increase out-of-passband attenuation. The surface acoustic wave filter device includes an unbalanced signal terminal, first and second balanced signal terminals, and first and second surface acoustic wave filters having input and output impedances. In each filter, one of the input and output impedances is approximately four times the other impedance. Additionally, 2 first surface acoustic wave filters are connected between the unbalanced signal terminal and the first balanced signal terminal, and 2 second surface acoustic wave filters are connected between the unbalanced signal terminal and the second balanced signal terminal, where n is an integer of 1 or more. The second surface acoustic wave filters are 180 degrees out-of-phase with respect to the first surface acoustic wave filters.