| 摘要 |
A duplexer excellent in power resistance comprising a transmission side filter of rudder type circuitry, and a reception side filter having a balance-imbalance converting function, in which impedance can be matched easily to that of a circuit having a balance input terminal connected with the first and second receiving output terminals of the reception side filter, and breakdown of the reception side filter due to leakage of power from the transmission side filter to the reception side filter is hard to occur. A duplexer (1) comprises a transmission side filter (4) of rudder type circuitry and a reception side filter (5), wherein the reception side filter (5) has an input terminal (6) connected with an antenna terminal (3), and first and second receiving output terminals (7, 8), the input terminal (6) is connected in parallel with first and second filter elements (11, 12) having a plurality of longitudinal coupling resonator type IDTs such that a plurality of IDTs (11a, 12a) are connected, and the first and second filter elements (11, 12)are connected with the first and second receiving output terminals (7, 8).
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