| 摘要 |
PURPOSE:To prevent attenuation of an output power due to a DC cut-off capacitor by giving an FET bias power from a dummy port side of a 90 deg. hybrid synthesizing outputs of two FETs excited by a phase different from 90 deg. so as to eliminate the need for the said capacitor between each FET and a common-phase hybrid. CONSTITUTION:FETs 1, 2 are given with excitation of difference phase by 90 deg., its output is fed to input ports A, B of a 90 deg. hybrid 9 via lines 5, 6 and then a synthesized output is caused at an output port C and a dummy port D is terminated by a dummy 10. Then a bias voltage EB is fed from the dummy port D of a hybrid 9. Thus, a bypass capacitor 21 insulating the point from ground in terms of DC and a DC cut-off capacitor isolating the dummy 10 in terms of DC are provided. The bias to the FETs 1, 2 is given respectively fro lines 5, 6 from the hybrid 9. Through the constitution above, it is not required to provide a DC cut-off capacitor between the FETs 1, 2 and the hybrid 9 and the attenuation of the output power such as a microwave is prevented by the capacitor. |
