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. 30, 2005
Filed:
Feb. 10, 2004
Michiaki Takagi, Tatsuno-machi, JP;
Masahiro Oshio, Suwa, JP;
Satoru Hayashi, Okaya, JP;
Katsuro Yoneya, Toyoshina-machi, JP;
Michiaki Takagi, Tatsuno-machi, JP;
Masahiro Oshio, Suwa, JP;
Satoru Hayashi, Okaya, JP;
Katsuro Yoneya, Toyoshina-machi, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
The invention provides a longitudinal double-mode SAW filter that has a large reflection coefficient by the electrode conductors and having flat pass band characteristics. In the longitudinal double-mode SAW filter, nearly all of higher-order natural mode oscillation displacements ASand Aare made present in the first and second interdigital transducer regions. An electrode finger phase weighting is formed to correspond to a BPSK sign where a phase sign changes into 0 or π at a polarity-changing point on an electrode charge distribution function Q(x) that generates on the electrode due to natural modes of oscillation. A single pair of natural modes, which exist stationary in the direction X of propagation of the surface acoustic waves that are utilized, is selected. A symmetrical mode charge distribution (Q(x), −Q(x)) and an obliquely symmetrical mode charge distribution (Q(x), Q(x)) are generated in order to correspond to the regions of IDTand IDTThe PTNG in the control IDTregion is set to be in the range of 1.02 to 1.04 so as to couple the two together.