SU1524012A1 - Method of measuring dielectric permittivity - Google Patents

Abstract

This invention relates to holography. The purpose of the invention is to improve the accuracy and resolution of the measurement. The essence of this method for measuring the dielectric constant (DP) of a surface is that the surface area under investigation is irradiated with signals of two mutually orthogonal polarizations relative to the horizontal plane. Then, the reflected signals are measured and the real and imaginary parts of the complex DP are determined. To achieve the goal, the reflected signal is additionally measured at one of the cross-polarizations relative to the horizontal plane. In addition, the signals of the own radiothermal radiation of the elements of the investigated surface area are also measured at two mutually orthogonal polarizations relative to the horizontal plane. Using the data obtained by the formula, determine the DP surface. Dana il. the implementation of the device that implements this method. 2 Il.

Description

This invention relates to holography and can be used in geophysics and oceanography.

The purpose of the invention is to improve the accuracy and resolution of measuring the surface dielectric constant.

FIG. Figure 1 shows the geometry of the problem to be solved for emitting oscillations with vertical polarization; in fig. 2 is a schematic of the device that implements a method for measuring the dielectric constant.

A device that implements a method for measuring the dielectric constant contains a transmitter 1 connected to two main outputs with transmitting antenna 2, receiving antenna loop 3, diagrams of blocks 4 and 5, receivers (linear parts of receivers) 6-8, quadrature converters 9-11, drivers 12 - 18 signals, radiometers 19 and 20, blocks 21 and 22 of signal multipliers, blocks 23 and 24 of subtractive devices, block 25 dividers, driver of signals 26, registration blocks 27 and 28,

The method is implemented by the following method.

five

A flat area covered with Christmas irregularities is placed at the origin of the XYZ system, the orientation is specified by the normal vector of the p. Q

The line AO lies in the ZOY plane, is the line of sight, indicates the direction of the wave falling on the acetone. 9 is the angle between the line of sight of the AO and the vector n, the vector ofmama to the middle surface XOY, coinciding in direction with the direction of the coordinate axis OZ. The vector E corresponds to the direction of the intensity vector of the electric field, 2π for a vertically polarized wave relative to the median XOY plane. The vector E-d corresponds to the direction of the vector of intensity of the electric field for a field of polarization 25, vertical to the facet of the facet plane, lies perpendicular to the surface section of the plane AoP passing through the line of sight of the AO,

6, the angle of incidence of the wave on the surface area. The plane E, OE is perpendicular to the plane ZOY, the plane ZOY and the plane AOP form a dihedral angle, the linear angle of which e 3 lies between the vectors E and E I.

From point A, oscillations of two mutually orthogonal polarizations are emitted, irradiated by these oscillations of elec

The cops of the investigated surface area receive the reflected signals of two main mutually orthogonal polarisations and one of the cross relative to the horizontal plane, as well as the signals of the own radiothermal radiation of the surface area. The reflected oscillations are received by the antenna array 3, which is common for receiving reflected signals and thermal radiation, the grid plane contains a flight line that is vertically or horizontally arranged, here the polarization selection of both reflected signals and thermal radiation is carried out. For separation in the reception channels, the oscillations of the main and cross polarizations are necessary

n 5

five

The emission of polarization oscillations at different, close frequencies is observed.

With the help of the grid 3, the diagram-forming blocks 4 and 5, fans of rays at each polarization are formed covering the viewing sector and spatial filtering of the signals is performed.

Frequency filtering and amplification of the reflected signals of the main and one of the cross polarizations is carried out in the linear parts of the channel receivers 6-8. Receiver 6 is tuned to the frequency corresponding to the frequency of the emitted signal with horizontal polarization, and receivers 7 and 8 are tuned to the frequency corresponding to the frequency of the emitted signal with vertical polarization.

The actions of spatial filtering, frequency filtering, and amplification can have a different sequence in time and can be performed at both high and intermediate frequency. This leads to a variety of schemes that implement the proposed method.

The signals of the three polarizations are then subjected to quadrature conversion in quadrature converters 9-11, which form signals proportional to the real and imaginary parts of the complex amplitudes of the corresponding high-frequency signals acting on the inputs of the quadrature converters.

. „.. ReYse- ReYrr a ctg 20,

ImYftj - IfnYrr YBB - Y

21Lvg

2T

rr

(one)

VG

- valid

and imaginary parts of the complex amplitudes of the signals of the vertical, horizontal and cross polarizations, respectively, relative to the horizontal plane,

12 form signature cotangents

five

doubled linear corners 6 of three dihedrals of 5 corners, in accordance with formula (1). This operation begins a sequence of actions that allow the transition to signals of mutually orthogonal polarizations, which are horizontal and vertical with respect to the coordinate systems associated with local plane 1 and the slopes of the set of resolvable relief elements.

In the signal conditioner 13-16, the received signals, proportional to the values a - ctg 263, are converted into signals proportional to the values tge3, ctg 63,, In the signal conditioner 17, signals are produced according to the formulas

,,;

(2)

YBB YeB +

 its ctgOjYg,, and at the same time form signals proportional to the complex amplitudes of the signals of two mutually orthogonal polarizations, reduced to the local planes of the slopes of the relief elements for each allowable direction Y. and Y, and then in

Bp

shaper received signals

ratios of these amplitudes

convert to signals

Y- / U. VV

The signals of own radiothermal radiation, obtained as a result of spatial filtering in blocks A and 5, convert into signals proportional to the radio temperature temperatures of resolvable relief elements at two mutually orthogonal polarizations for each allowable direction separately T .. and T ,, g . This action is performed by radiometers 19 and 20 with scanning or multichannel radiometers using beam-forming circuits.

The received signals, proportional to radio radiant temperatures, are multiplied in blocks 21 and 22 by signals proportional to the values of sin 63 and cos b.

In the subtractors 23 and 24, the received signals are subtracted from one another according to the formulas

63T ,, cos

T ,, sin

 near;

-Y6

dn a

r

0

five

0

five

As a result of performing these actions, signals are generated that are proportional to the radioactivity temperatures of the resolved relief elements, for polarizations brought to these

t m slopes

plane elements T.

at

In block 25, one of the received signals (any) is divided by the other for polarizations of the slopes of the resolvable elements reduced to local planes. Thus, using these actions, a transition is made from the coordinate system associated with the horizontal plane to the local coordinate systems associated with the local inclinations of the individual relief elements.

The received signals are converted in a decisive (computing) device of analog or digital type (driver 26) into signals proportional to the dielectric constant by solving a system of nonlinear equations

thirty

(four)

As a result of these actions, images of the real (recording unit 27) and imaginary (recording unit 28) parts of the complex dielectric constant are formed (in the particular case of real, the second image is zero).

sSI3 yee t ,, t, in

; j-5- tT- - grT-y-J-yi i «g

l with: i L-rt and yjit

t g

 not

/ m-s-j i liu.

2 1 - 2

-sh-s-li,

TS

f + ilL

(five)

50

55

Single-channel and multichannel solutions of the above device with a scanning antenna are possible.

Variants of stationary-type devices are possible, which can be mounted on helicopters or spacecraft capable of being stationary for some time relative to the surface. Then the system must form a set of rays covering the entire specified surface area using a two-dimensional antenna array.

Claims (1)

Invention Formula The method of measuring the dielectric constant, which consists in irradiating with the signals of two mutually orthogonal polarisations relative to the horizontal plane of the investigated surface area, measuring the reflected signals V .., Y and the real and imaginary parts of the complex dielectric constant, characterized in that, in order to improve accuracy and resolution, the reflected signal is additionally measured on one of the cross fields Y arrangements and Y, in g d in the horizontal plane relative to goi, the signals of the own radiothermal radiation T, T, of the elements of the investigated surface area on two mutually orthogonal polarizations relative to the horizontal plane, and the dielectric constant determined by the formula S . S 5 ps Yb T, g T „  t1G S fir   t Y 1 - 2 i4 - + i years T; and t :. - radio brightness temperatures of resolvable elements, reduced to local planes of inclination of relief elements; "at T, BC05 T T., sin 2 e z T ,, - T, B1p bz. cos 65 - sin b S cc yy the complex amplitudes of the signals of the vertical and horizontal polarizations, reduced to the local planes of the slopes of the relief elements (the calculations use either real or imaginary parts of the complex amplitudes);  Y Bv , Y ,, + ctgOj YB, + y.vg; Y, r Y ,, - Y.B - ctgQjYer, where 0j is the linear angle of the dihedral angle formed by the vertical plane of radio wave incidence on the surface relief elements and the plane of incidence perpendicular to the plane of inclination of these slopes, calculated by the formula ctg 26 - - - Y, -Chu-wg FIG.