| 摘要 |
<p>There is provided a duplexer with high power handling performance which includes a transmission filter having a ladder circuit configuration and a reception filter with a balanced-to-unbalanced conversion function and is capable of easily achieving the impedance matching between the reception filter and a circuit including a balanced input terminal connected to first and second reception output terminals of the reception filter and preventing the reception filter from being damaged due to electric power supplied from the transmission filter to the reception filter. A duplexer (1) includes a transmission filter (4) having a ladder circuit configuration and a reception filter (5). The reception filter (5) includes an input terminal (6) connected to an antenna terminal (3), a first reception output terminal (7), and a second reception output terminal (8). A first filter element (11) and a second filter element (12), each of which is a longitudinally coupled resonator filter element including a plurality of IDTs, are connected in parallel to the input terminal (6) so that IDTs (11a and 12a) are connected to the input terminal (6). The first filter element (11) and the second filter element (12) are connected to the first reception output terminal (7) and the second reception output terminal (8), respectively.</p> |
