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. 13, 1989
Filed:
May. 26, 1987
Gerald E Roberts, Lynchburg, VA (US);
A Gordon Staples, Evergreen, VA (US);
Samuel Toliver, Rustburg, VA (US);
General Electric Company, Lynchburg, VA (US);
Abstract
A monolithic coupled-dual resonator crystal filter is produced for operation with wide bandwidths (especially at high center frequencies) by providing an ultra-small gap between juxtaposed resonator electrodes. A gap width of substantially less than 0.006 inch is obtained by laser-machine trimming the gap. An initial single electrode may thus be divided into a pair of such juxtaposed resonator electrodes. Further metallic plate-back is provided on the electrodes for center-frequency control. Although this typically may decrease the coupling bandwidth somewhat, an increased thickness of metallic plate-back material on the ground electrode, opposite the ultra-thin gap area on the active side of the crystal wafer, provides precisely controlled extra wide bandwidth.