| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a technique for implementing a favorable isolation characteristic in configuring a duplexer by arranging a transmission side filter and a reception side filter on a common piezoelectric substrate.SOLUTION: A low pass filter 10, which is either of the transmission side filter and the reception side filter, is configured as a ladder filter including series arms 21-24 and parallel arms 31-34. The second and third parallel arms 32, 33 counted from the side of the low pass filter 10 are arranged on the right of a series signal path 11 and connected to a shield electrode. The first parallel arm 31 counted from the side of the low pass filter 10 is, on the other hand, arranged on the left of the series signal path 11 and electrically isolated from the shield electrode 6.</p> |
