| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress spurious noise occurring at the side of a frequency higher than the center frequency of a cascade type multiple mode piezoelectric filter. <P>SOLUTION: First and second multiple mode piezoelectric filters 1, 2 include: a piezoelectric substrate 5; a plurality of split electrodes 10, 11 adjacently arranged on one main surface of the piezoelectric substrate 5; and a common electrode 12 arranged opposite to all of the split electrodes 10, 11 on the other main surface of the piezoelectric substrate 5. In this case, the area of the common electrode 12 of the multiple mode piezoelectric filter 1 differs from that of the common electrode 12 of the second multiple mode piezoelectric filter 2. <P>COPYRIGHT: (C)2009,JPO&INPIT |
