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:
May. 19, 1992
Filed:
Apr. 07, 1989
Mitsutaka Hikita, Hachiouji, JP;
Toyoji Tabuchi, Tsukui, JP;
Kazuhito Kurosawa, Nakaminato, JP;
Nobuhiko Shibagaki, Kokubunji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Disclosed is a SAW filter employing a SAW resonator which is constructed of a plurality of pairs of electrode fingers formed on a piezoelectric substrate, and in which a plurality of SAW transmission spaces are included. The SAW transmission spaces do not have the function of exciting a SAW, and they have electric lengths which match the phases of SAWs excited by the resonator. In accordance with frequency characteristics required of the filter, such SAW transmission spaces are introduced into, for example, one of a plurality of SAW resonators located on the electric power input side of the filter.