| 摘要 |
PURPOSE:To attain stable attenuation whose passing characteristic in an RF signal transmission line is not affected by coupling a bias voltage input circuit-DC low-pass circuit to the midpoint of an RF reflection power termination resistor. CONSTITUTION:PIN diodes 4, 5 whose one end is grounded in terms of high frequencies are provided at points having a line distance of 1/4 wavelength of the operating frequency on a Y branch line 10 respectively. Resistors 11, 12 having nearly the same characteristic impedance as the Y branch line are connected between the two Y branch lines 10. A bias voltage input circuit connected to a bias voltage input terminal 3 is connected to the midpoint of the resistor 11. Then even when the characteristic of a DC low-pass circuit has a change, it is absorbed by the resistors 11, 12. Thus stable attenuation is applied while the pass characteristic of the RF signal transmission line is not affected.
|
