| 摘要 |
A directional coupler is configured to include: a first signal transmission line disposed between a signal input terminal and a signal output terminal; a coupling line disposed between a coupling output terminal and a resistive connection terminal and electromagnetically coupled to the first signal transmission line; switching terminals connected to a switching element of an IC chip; and a second signal transmission line the connection state of which to the first signal transmission line is switchable in response to a connection switching operation between the switching terminals by the switching element. When an electric signal in a low-frequency first frequency band is inputted to the signal input terminal, the second signal transmission line is parallel-connected to the first signal transmission line 1 in response to the connection switching operation between the switching terminals by the switching element. |
