| 摘要 |
PURPOSE:To increase the variable range of attenuation even at a high frequency band by inserting a distributed constant transmission line between a port of a 3dB hybrid and a PIN diode. CONSTITUTION:Distributed constant transmission lines 11a, 11b are inserted between a coupling port 3 of the 3dB hybrid circuit 7 and the cathode of a PIN diode 5a and between a passing port 4 and the cathode of the PIN diode 5b respectively so that the impedance of the PIN diode is coincident with the characteristic of the 3dB hybrid circuit in its operating frequency. Thus, the reflection coefficient is decreased and the insertion loss is reduced, then the variable range of attenuation is increased. |
