| 摘要 |
<p>In a directional coupler, even when parasitic inductance exists, an increase in device size is suppressed while obtaining good isolation characteristics. A transmission line type directional coupler (20A) includes a main line (21) and a sub line (22) that is coupled to the main line (21) through electric field coupling and magnetic field coupling. The main line (21) includes a signal input port (RFin) and a signal output port (RFout), and the sub line (22) includes a coupling port (CPL) and an isolation port (ISO). Here, a series capacitor is connected to only one of the signal output port (RFout) and the coupling port (CPL).</p> |
