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:
Mar. 11, 1986
Filed:
Oct. 29, 1984
John Schofield, Coulsdon, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
A low insertion loss surface acoustic wave filter in which withdrawal weighted launching and output transducers 20, 40 are acoustically coupled by two high efficiency reflective multistrip couplers 6, 6'. To reduce the insertion loss, the inner bus bars 21, 41 are reduced in width so as to reduce the dead space 12 in the coupler. This makes it impossible to form a reliable wire bond connection to the inner bus bars which are therefore connected via a conducting path across the propagation path at the ends of the transducers. Further reduction in the widths of the inner bus bars and consequent increase in resistive losses are offset by several connections to a further bus 23, 43 via groups 25 of dummy electrodes arranged at null points in the weighting pattern.