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:
Aug. 25, 2009
Filed:
Jul. 01, 2005
Michiaki Takagi, Suwa, JP;
Katsuro Yoneya, Azumino, JP;
Masahiro Oshio, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
A longitudinally coupled multi-mode SAW resonator filter includes input and output interdigital transducers (IDTs) with a control IDT therebetween to control a state of the surface acoustic wave. The input, output, and control IDTs alternatively arrange two different zones C and E having respective electrode period lengths PC and PE, being equal to a sum of the electrode finger width L and spacing S between electrode fingers, and a number of respective pairs MC and ME of electrode fingers is set to 1 in both zones C and E. Electrode fingers in zones C and E are all connected to a feeder conductor. Hence, a filter having small insertion loss, and a wide fractional bandwidth of 2000-4000 ppm is achieved by canceling and decreasing sums of reflected waves from the electrode fingers in zones C and E, and decreasing the effective reflection coefficient per the electrode finger.