| 摘要 |
There is included a switch (SW) that has a first port (P1) for inputting/outputting unbalance signals of a first frequency band, a second port (P2) for inputting/outputting unbalance signals of a second frequency band, and a third port (P3) common to the unbalance signals of these two frequency bands, and that switches signal paths. The port (P1) is connected to an unbalance input/output port (P4) of a first filter (F1) that passes the signals of the first frequency band. The port (P2) is connected to a port (P7) of a second filter (F2) that passes the signals of the second frequency band. The balance input/output ports of the first filter (F1) are connected to the respective balance input/output ports of the second filter (F2) at respective first and second branch ports (B1,B2) by use of approximately equal electrical lengths. An impedance-matching balance coil (BC) is connected between the first and second branch ports.
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