| 摘要 |
PURPOSE:To reduce insertion loss over a wide band by connecting a network to be turned to a constant resistance value when a reverse bias for turning off a diode switch is applied directly to a wide band RF choke. CONSTITUTION:A load 12 with load impedance ZL (=ZO) is directly connected to a signal source (transmitter) 11 with internal impedance ZO and a pin diode 13 is connected to a load 12 in parallel. The wide band RF choke 14 is connected to the pin diode 13 in series and the network 17 to be turned to a constant resistance at the time of reverse bias against the pin diode 13 is connected to the choke 14 in series. The network 17 is constituted of serial connection between a 1st circuit 17a and a 2nd circuit 17b, the 1st circuit 17a is constituted of a parallel circuit consisting of a resistor R1 and an inductor L and the 2nd circuit 17b is constituted of a parallel circuit consisting of a resistor R2, a variable capacitor CV and a diode D. Consequently, insertion loss can be reduced over the wide band.
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