SU1337825A1 - Device for measuring parameters of materials - Google Patents

Abstract

The invention allows to expand the functionality of the device by providing a measurement of the dielectric, permeability. The device contains an auto-oscillator 1, a Y-circulator 2, a directional coupler (BUT) 3, an adjustable phase shifter 4, a measuring cell (OP) 5 with the dielectric under study (ID), an automatic power stabilization unit 6 consisting of BUT 7, a detector 8, the amplifier 9 and the controlled attenuator 10, and the frequency meter 11. In the absence of the ID, the signal from the oscillator 1 passes through the HO. 3 - to the OC circuit. In this case, block 6, changing attenuation of attenuator 10, maintains a constant level of power returned to oscillator 1, regardless of losses in IL 5. When the ID is placed in IL 5, the frequency generated by the oscillator 1 is shifted. From the frequency offset recorded by the frequency meter 11, the dielectric permeability is determined. By introducing blocks 2, 6, 11, errors of setting the frequency of the signal of the oscillator are eliminated. 1 il. i (L 00 00 th ate

Description

The invention relates to a measuring technique and can be used to measure the dielectric constant of thin films, synthetic materials, fabrics, rubber and other dielectric materials and products in the process of their manufacture and operation.

The purpose of the invention is to expand the functionality by measuring the dielectric constant.

The drawing shows the structural electrical circuit of the device for measuring the parameters of materials.

A device for measuring material parameters contains autogeneration 1, Y-circulator 2, directional otvetvitel 3, adjustable phase shifter 4, measuring cell 5 with dielectric under study, block 6 of automatic power stabilization, including directional coupler 7, detector 8, amplifier 9 and a controlled attenuator 10, a frequency meter 11.

A device for measuring the parameters of materials works as follows.

In the absence of a dielectric material in the measuring cell 5, the microwave signal from the self-oscillator 1 through the Y-circulator 2 and the directional coupler 3 enters the additional feedback circuit consisting of the phase rotator 4, the measuring cell 5, the controlled attenuator 10 and the directional the coupler 7. A part of the microwave signal simultaneously through the directional coupler 7 enters the automatic stabilization power unit 6, which, automatically changing the attenuation of the attenuator 10, maintains a constant level returned to Autogen Ator 1 power regardless of losses in the measuring cell 5.

Before the measurements, the device is calibrated, consisting in setting up the circuit of additional external feedback using the phase shifter 4 to a point when the phase difference between the emitted and reflected signals of the auto-oscillator 1 is zero. The indication of the correct calibration is the absence of frequency mixing of the oscillator 1, measured by frequency meter 11, with a mini

five

B

0 0

B

five

WITH

five

minimum and maximum attenuation attenuator 10.

When a tested material or product is placed into the measuring cell 5, the generated frequency of the oscillator 1 is shifted, which is recorded by the frequency meter 11. With the frequency Jf, the dielectric constant f is determined by the formula

EG (V. Af + 1),

where B is a certain constant coefficient, depending on the thickness of the material or article under investigation, on the frequency and quality factor of the oscillating system of the microwave generator, on the parameters of the additional external feedback circuit.

Thus, an increase in the accuracy of measurements is provided, due to the fact that the error of setting the frequency of the microwave generator signal is eliminated. Since the condition of the balance of amplitudes and phases in the microwave generator is not violated when measuring the dielectric constant, the change in frequency in the oscillator exactly corresponds to the change in f. At the same time, the accuracy of measuring the frequency offset f can be arbitrarily high and is determined by the accuracy of the measuring devices used.

D (; device is also capable of measuring dielectric materials having a small thickness (on the order of 0.1-10), for example, dielectric films, substrates and other products.

Claims (1)

Invention Formula A device for measuring the parameters of materials, containing an auto-generator, a directional coupler, to the output of the main arm of which an input of an adjustable phase shifter is connected, the output of which is connected to the input of the measuring cell, so that, in order to extend the functionality by providing dielectric constant measurement , an automatic power stabilization unit, a frequency meter and a circulator, the first arm of which is i4ie / inneHO with the output of the microwave generator, are introduced into it, 31337825 the second arm is connected to the input and the output of the measuring cell through the main arm of the directional response is the automatic stabilization unit, the output of the auxiliary power is connected to the third arm of the arm of which is connected to a frequency meter, a circulator.