US Patent 7146137 High-frequency switch

To provide a high frequency switch capable of dealing with multiple frequency bands without having plurality of switch circuits. A first diode that conducts due to a bias current when a first switch is closed is interposed between first signal terminal and a second signal terminal. A strip line with the electrical length L1 is connected to the cathode of the first diode, the other end being grounded. At a position with a distance L2 from one end of the strip line, a capacitor and a second switch are connected to be equivalently grounded when the second switch is closed. The strip line resonates with the electrical length L1 when the second switch is opened, and resonates with the electrical length L2 when the second switch is closed.