BAND FILTER EMPLOYING THIN FILM PIEZOELECTRIC RESONATOR,申请号JP20020321210-传众专利搜索

BAND FILTER EMPLOYING THIN FILM PIEZOELECTRIC RESONATOR

申请公布号：JP2004158970(A)

申请号：JP20020321210

申请日期：2002.11.05

申请公布日期：2004.06.03

申请人：

UBE IND LTD

发明人：NISHIMURA KOSUKE;FUJINAGA MASATAKA;KONDO MASAHIDE

分类号：H03H9/58;H03H9/17;H03H9/56;(IPC1-7):H03H9/58

主分类号：H03H9/58

摘要：PROBLEM TO BE SOLVED: To provide a filter for enhancing stop band attenuation characteristics without changing the entire size of the filter and deteriorating the insertion loss in the case of configuring the ladder filter with a thin film piezoelectric resonator. SOLUTION: In the band filter including a thin film piezoelectric resonator for series elements and shunt elements for configuring the ladder circuit having a first and a second terminals whose characteristic impedance is Z0 and provided with the series elements and the shunt elements between the first and second terminals, let the characteristic impedance of at least one of the series elements be Z1, and let the characteristic impedance of at least one of the shunt elements be Z2, relations of 1<(Z1/Z0)<2 and 0.5<(Z2/Z0)<1 hold among the characteristic impedances Z0, Z1, Z2. COPYRIGHT: (C)2004,JPO