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. 26, 1997
Filed:
Jun. 06, 1995
Roland Dill, Munchen, DE;
Jurgen Machui, Munchen, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A filter operating with acoustical surface waves includes two acoustical paths each having one unidirectional input transducer, one unidirectional output transducer, and a reflector structure disposed between the input and output transducers. The input transducers in the acoustical paths are structurally identical, the output transducers in the acoustical paths are structurally identical, and the input and output transducers in each of the acoustical paths are spaced apart by the same distance. One of the input transducers or the output transducers are electrically connected in phase opposition, and the other of the input transducers or the output transducers are electrically connected in phase. The reflector structures in the two acoustical paths have substantially the same reflection performance, the reflector structure in one of the acoustical paths is shorter than the reflector structure in the other of the acoustical paths by .lambda./2, the reflector structures in the two acoustical paths are disposed centrally between the input and output transducers, and .lambda. is a wavelength at a mean frequency of the filter.