SU1506388A1 - Method of measuring dielectric permittivity of solid materials - Google Patents

Abstract

This invention relates to radiophysical measurements of dielectric parameters. The purpose of the invention is to improve the measurement accuracy. The goal is achieved by measuring the parameters of a standing wave in a waveguide with a sample of the material under investigation, the side surfaces of which are in contact with the walls of the waveguide, and calculating the dielectric constant from these parameters. A viscous dielectric with a dielectric constant approximately equal to the calculated one is selected, which fills the gaps between the walls of the waveguide and the side surfaces of the sample, after which they re-measure the parameters of the standing wave in the waveguide with the sample of the material under investigation and calculate them permeability. The measuring device contains Mr. microwave 1, valve 2, measuring line 3, indicator 4, detector 5, probe 6, waveguide section 7, viscous dielectric 9. 4 Il.

Description

1

The invention relates to the field of radiophysical measurements of parametric dielectrics, in particular, to the waveguide methods for measuring the dielectric constant (B) of solid materials, and can be used to determine solid materials in the high and superhigh frequency ranges for the study of electricians with high values 6

The aim of the invention is to improve the measurement accuracy.

Figure 1 shows the structural electrical circuit of the device, directing a method for measuring the dielectric constant of solid materials; on. FIG. 2 - diagrams of a standing wave in a waveguide without a sample (a) and with a sample (b); Fig. 3 shows the location of the material in the waveguide and section A-A in Fig. 4 is a plot of the dependence.

 f (e ,, p

iC2 V () when using the mixture component: I - technical petrolatum (, g D), C - titanium dioxide powder (80).

Dependence in this case (fig. A

has the appearance of 6cm antilg o, 602V, +

- 1,903 (1 - V,) (6, 8, and the value of the dielectric constant of the viscous dielectric, its first and second components corresponding to V is the volume concentration of the perio component, j

Fig. 1 shows a microwave generator 1, a gate 2, a measuring line 3, an indicator A, a detector 5, a probe 6, a waveguide section 7, a sample 8 of a solid material under study and a viscous dielectric 9.

The method for measuring the dielectric constant of solid materials is as follows.

A sample of the studied solid material is made with dimensions of a cross section that are slightly smaller than the cross section of the waveguide. Install a fabricated sample of solid material in the waveguide close to the short circuit.

a record. Measure

KB 1 6 g using the measuring line, where K - coefficient of the traveling wave; L "- wavelength in

waveguide; x

m

6 offset value

the minimum of the cost of a wave in a waveguide. From the measured values of Kp, x and the sample size of the material, the first approximation of the dielectric is calculated.

in d

e- 15 ae 20;

WITH)

25

- -

permeability of the material. Choose the type (c6ga-f viscous dielectric dielectric, or if there is no viscous dielectric with the required value), a binary bond is prepared, for example, from technical petroleum jelly and TiO in accordance with the above formula. A layer is applied to the lateral surfaces of the sample of solid material viscous dielectric, set the sample of solid material in the waveguide and remove the influx of viscous dielectric at the end of the sample of solid material and the walls of the waveguide. Additionally, measure Kg, "and x, Dopol1P1to calculate the dielectric constant of the solid th material from the measured parameters.

The principle of measurement and calculation is based on the following.

In the waveguide, excited on the one hand by the microwave generator and short-circuited on the other, a standing wave with nodes located at a distance -, from each other and from the short-circuiting plate is installed, Lz being connected to the boundary wavelength A and length free-space waves

at

 Ac

four

l ./ "g)

0

5 falling

0

five

If a sample of a solid material is placed in a waveguide close to a short-circuit plate, the standing wave pattern changes: the field strength at the nodes does not reach zero, because the amplitude of the reflected wave does not become smaller than the amplitude of the reflected material. Moreover, all the minima (nodes ) The BOL1P 1 position shifts towards the sample of a solid material, since its wavelength is less than the wavelength in a hollow waveguide. These changes in the pattern of the standing wave depend on the properties of the test sample of solid material and can be related to its electrical characteristics by a certain ratio resulting from the solution of the corresponding electrodynamic problem. The solution of this problem, taking into account the conditions on the sections of the section, leads to a complex

5 1506388

transcendental equation connecting the characteristics of a solid material with H3MepHeNtt) iMn tins 13 .1 h

coefficient of the traveling wave Kg and the position of the node; 1 standing wave relative to the surface of the sample.

This equation is nid

,

where .f

D

e

g is determined by the form- (2)

V -

1-t Jle,., L B- 1 - j K tgO

sb

- constant r.spreadsil solid material;

-the thickness of the material obrac; i1;

-phase U1OL, appropriately, iy;) Yu from the surface of the sample of solid material to the first node of STO T - whose wave,

The pev's part of the uraptgeni () coaep Kin values 1., D and x, which) are determined by the help of a freshwater measuring line, equipped with a chalk, with a microwave generator and a full-flowing section with a sample - solid matter having the same cross-sectional cross section as well as the section containing the i-Bep sample of this material, the traveling wave ratio is measured at the points that are located near the standing wave node. If points are chosen, at which the readings of the indicator instrument (with a quadratic character of the detector) are 2 times its minimum i, then K,

le

II and X

)

where L X is the distance between the points of double min.

The distance x between the surface of the sample of the hard material and the first-half standing wave node is determined from the expression

x ".

(3)

Where

1 offset of any node due to the introduction of a sample of solid material. The determined values of the values of K, L., their, and also about

However, the previously measured sample thickness allows us to calculate the right-hand side of Eq. (1), and then the spreading size of the propagation associated with f and the following formula is known from waveguide theory:

 -, ie - (- A „/ D,) -. (BUT)

-Ti, 13 .1 calculation of constant distribution; r from equation (1 can be either graphically or numerically by the method. The resulting value of V

(M

and found

r-set in the equation of lit. and c.

Repeated measurements of pairs, 1 meter of a standing wave in a waveguide with a sample of solid MarepHtUia placed in it, the gaps between which are three-fold viscous digesters, and 1) ;: due to the correct parameters of the dielectric permeability, it is possible to find differing from them by no more than 1-2%. If high accuracy is required, then after the blood test and re-measurement: and

iyih - i: i

g- (21,

calculating t q (where

- dielectric core. solid matter content, obtained as a result of repeated measurements (5 PIP), it is necessary to prepare viscous

Gf (i1

dielectric with e-yes with C) in the form of oin: an ip mixture, for example, technical petrolatum — titanium dioxide (6-o; o C), using the well-known screen of displacement

0

ig6 ,, X4ige, -u

- V,) ige, (5)

five

ABOUT

five

Then, it is necessary to remove a sample of solid material from the waveguide, to lay a layer of the former viscous dielectric from its side surfaces and walls of the waveguide, to install a sample of solid material into the waveguide, filling the gaps with a viscous dielectric with f а a / -С71

 with IJ, prepared in accordance with (5), and conduct ea: e alone measuring the parameters of a standing wave in a waveguide with a sample of a solid matter, from which to calculate EL. If necessary, the described operations can be performed several times, until reaching

fulfillment of the inequality / t, q

-, m-o

.(AND)

where i

with

W.e,

specified value

MoI 1g is measured by 1I,

Fore

ula invention

55

A method for measuring the dielectric constant of solid materials, which is measured (P1 is a pair of standing waves in a waveguide with n-shchichii and the absence of solid material in it

and calculating the dielectric resistance of a solid material from measurements of parameters to parameters differing from the fact that, for the purpose of understanding the accuracy of these measurements, the gap between the waveguide wall and the solid material is filled with an hc dielectric.

whose dielectric constant is approximately equal to the calculated dielectric constant, the parameters of the standing wave are measured, and the dielectric constant of the solid material is calculated with respect to 1 measure.

SrigZ

From general- / poro

ft-A

WMTMfWf,

h

80

DZ

f.ff I //

Claims (1)

Claim DG about measuring the dielectric constant of solid materials, which consists in measuring the parameters of a hundred-cell wave in a waveguide in case of the absence of solid material in it Ί 1506ZY8 and calculating the dielectric constant of the solid material according to the measured parameters, distinguishing also by the fact that, in order to improve the measurement accuracy, the gap between the waveguide wall and the solid material is filled with a viscous dielectric, the dielectric constant of which is approximately equal to the calculated dielectric constant, and the standing parameters are measured waves and calculate the dielectric constant of the solid material from the measured parameters izlv | <7 22222 ^ 772272 22777722222222727222222222222227777777777? ϊ! G / 5722272^2222227777722222222272^2272222222272722.72^. From general1 toro zs I Fig 2 AH I I n ± ΖΖΖΖΖ ΖΖ 772? 772 / 2-7277772'777722772272222ΖΔ ΖΣΣΖΖΖΖΖΖΖ ^ /// 2 /////// 2/2/277 ^ 10t generator τζζζζζζζζζζ FIG.3 FIG.