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:
Sep. 19, 2006
Filed:
Apr. 14, 2003
Ryoichi Takayama, Osaka, JP;
Shunichi Seki, Hyogo, JP;
Tetsuo Kawasaki, Osaka, JP;
Hidekazu Nakanishi, Osaka, JP;
Koji Hasegawa, Hokkaido, JP;
Ryoichi Takayama, Osaka, JP;
Shunichi Seki, Hyogo, JP;
Tetsuo Kawasaki, Osaka, JP;
Hidekazu Nakanishi, Osaka, JP;
Koji Hasegawa, Hokkaido, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a surface acoustic wave (SAW) device, such as a SAW resonator or a SAW filter, loss is minimized and steep characteristics are improved. IDT electrodes and a reflector are provided to a piezoelectric substrate cut out at a cut-angle which allows the substrate to excite a leaky surface acoustic wave (LSAW). The IDT electrodes have a given film thickness and a given pitch 'p' of finger-electrodes. A phase velocity of the SAW is reduced to slower than a phase velocity 'vb'of a slow shear wave propagating on the piezoelectric substrate, and a resonance frequency “f” satisfies a relation of 2×p≦vb/f. This structure allows the use of a Rayleigh surface acoustic wave (RSAW) which does not produce propagation loss, and improving insertion-loss and steep characteristics from those of a conventional SAW device using the LSAW.