| 摘要 |
PURPOSE:To take high-precision measurement by constituting a microwave bridge in a microwave transmitting circuit and reducing a standing wave error. CONSTITUTION:A material 15 for measurement is put in a slit 14 for measurement and a radio microwave from a microwave oscillator 1 is divided into a wave propagating as shown by an arrow 18 and a wave propagating as shown by an arrow 20. The radio wave in the direction of the arrow 18 is attenuated by water in the material 15, reflected by a plunger 17, and led to a detector 9 as shown by a dotted-line arrow 19. The wave in the direction of the arrow 20, on the other hand, is passed through a variable attenuator 6 and reflected by a plunger 8 to reach a detector 9 as shown by a dotted-line arrow 21. Therefore, when signals of both arms are equal in attenuation quantity and 180 deg. out of phase with each other, an output signal is zero and an indicator 11 indicates zero. For the purpose, both arms are balanced before measuring operation and the amount of water is measured from the deflection of the meter when the radio wave is passed through the material 15. Further, the standing wave error due to the reflection of the plunger is small, so the precision of the measurement is high. |
