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:
Jun. 12, 1990
Filed:
Dec. 23, 1988
James A Greer, Andover, MA (US);
Raytheon Company, Lexington, MA (US);
Abstract
A technique for adjusting the frequency of odd mode transverse waves propagating in a SAW device is described. A pair of localized regions of frequency determining trimming material are deposited onto selected portions of a surface wave propagating surface, to provide localized regions on said surface where the odd order transverse mode has energy maxima. These regions change the acoustic properties and hence the velocity characteristics of the surface wave propagating surface in said regions. The frequency of the odd mode transverse wave is changed accordingly and is preferably changed to match that of the fundamental transverse propagating wave. This decreases the insertion loss of the device at the fundamental frequency and eliminates the odd mode transverse wave propagation characteristic within the operating frequency range of the resonator. In a preferred embodiment, the SAW device further includes an acoustically matched piezoelectric transparent cover disposed over the surface wave propagating surface having disposed thereon a trim pad which is selectively removed to provide the localized regions and thus the localized alterations in the acoustic properties of the surface acoustic wave device.