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:
Feb. 11, 2014
Filed:
Feb. 05, 2009
Tatsunori Onzuka, Sayama, JP;
Tatsunori Onzuka, Sayama, JP;
Nihon Dempa Kogyo Co., Ltd., Tokyo, JP;
Abstract
An object is to obtain a steep and large attenuation amount in attenuation bands close to each other out of a band of a TV wave and to provide a filter in which the use number of inductors is reduced thereby to be able to contribute to downsizing of a device. Elastic wave resonators of a plurality of parallel arms for each forming plurality of attenuation band are connected to the same electric potential point in a signal path without aid of an inductor. Otherwise, a series circuit of a plurality of element parts generating series resonance is connected in a signal path as a parallel arm. Therefore, a large attenuation amount can be obtained in each of the plural attenuation bands, but a region equivalent to what is called a zero point exists between adjacent poles. However, there can be obtained a characteristic in which steep attenuations occur in both sides of the zero point even if the zero point exists. Sets of elastic wave resonators (sets of resonators) connected to the same potential points or parallel arms constituted by the series circuits are connected in a signal path in a plurality of stages, and an inductor for inverting a phase intervenes between the stages.