SU466468A1 - Device for measuring the complex reflection coefficient - Google Patents

Description

I

The device can be used to measure the complex reflection coefficients of devices of microwave paths.

A device for measuring the complex reflection coefficient is known, comprising a microwave generator, a directional coupler, a mixer, a continuous phase shifter with a reference channel connected to it.

The purpose of the invention is to eliminate the measurement error associated with the final direction of the directional coupler.

The proposed device is characterized in that a continuous phase shifter is connected between the input of the measurement object and the output shoulder of the main channel of the directional coupler, the shoulders of the auxiliary channel of which are connected to an additionally inserted slot bridge connected to the mixer inputs.

The drawing shows the block diagram of the device.

The described device contains a microwave 1 generator, a decoupling attenuator 2, a directional coupler 3, a continuous phase shifter 4, a slot bridge 5, a mixer 6, an indicator 7, a phase shifter 8, and an attenuator 9 of the reference channel.

The device works as follows.

The signal from generator 1 through the decoupling attenuator 2 enters the directional

the coupler 3 and is divided into two parts. One part of the signal through the continuous phase shifter 4, which shifts the frequency of the signal by an amount and is fed to the object under study

10, and the other through the slotted bridge 5 to the mixer 6. The signal reflected from the object under study passes through the continuous phase shifter 4, where it is again shifted in frequency by the value of Q and fed through the slotted bridge

5 to the balanced mixer 6. This signal, which receives the frequency shift, carries information about the module and phase of the reflection coefficient of the object under study 5. Thus, the intermediate frequency signal 2Q is extracted from the sensitive elements of the mixer (platinum nitrometers in a thermal mixer mode) . The amplitude and phase of this signal depends on the modulus and phase of the reflection coefficient of the object under study. The specified signal is fed to the input of the indicator 7, which consists of a resonant amplifier and a phase detector. This also receives a comparison signal, for which an exemplary phase shifter 8 and attenuator 9 of the reference channel are used. Measuring the modulus and phase of the reflection coefficient of the object under study is reduced to a comparison with the modulus and phase of the signal reflected from a short-circuited waveguide piece.

For this, a signal is compared to an attenuator.

and the phase shifter is set equal to the modulus and antiphase signal of the intermediate frequency when both the object under study and the short-circuited waveguide are connected.

Subject invention

A device for measuring the complex reflection coefficient, comprising a microwave generator, a directional coupler, a mixer, a continuous phase shifter with a connection

A reference channel connected to it, an indicator connected to the outputs of the reference channel and a mixer, characterized in that, in order to eliminate measurement uncertainty associated with the final directionality of the directional coupler, the phase shifter is connected between the input of the measurement object and the output arm of the main channel of the directional coupler, shoulders the auxiliary channel of which is connected to an additionally inserted slot bridge connected to the inputs of the mixer.