Invention Grant
- Patent Title: Filter, portable terminal and electronic component
- Patent Title (中): 过滤器,便携式终端和电子元件
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Application No.: US12735611Application Date: 2009-02-05
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Publication No.: US08648672B2Publication Date: 2014-02-11
- Inventor: Tatsunori Onzuka
- Applicant: Tatsunori Onzuka
- Applicant Address: JP Tokyo
- Assignee: Nihon Dempa Kogyo Co., Ltd.
- Current Assignee: Nihon Dempa Kogyo Co., Ltd.
- Current Assignee Address: JP Tokyo
- Agency: Jordan and Hamburg LLP
- Priority: JP2008-025630 20080205; JP2008-163633 20080623
- International Application: PCT/JP2009/052350 WO 20090205
- International Announcement: WO2009/099248 WO 20090813
- Main IPC: H03H9/46
- IPC: H03H9/46 ; H03H9/54 ; H03H9/64 ; H03H7/01

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.
Public/Granted literature
- US20110102107A1 FILTER, PORTABLE TERMINAL AND ELECTRONIC COMPONENT Public/Granted day:2011-05-05
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