RU2537084C1 - Method of determining alternate electromagnetic field attenuation in space - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention refers to measurement equipment and can be applied in determination of electric parameters of space. Method involves placement of probe in the form of open flat capacitor screened from solar radiation by opaque screen, in space and feed of HF signals of definite frequency to the probe. Measurement data are obtained from the probe in the form of loss angle tangent and dielectric permeability of medium under examination, allowing for determination of attenuation rate per length unit for space.

EFFECT: possible determination of attenuation rate per length unit for space.

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Description

The present invention relates to measuring technique and can be used to determine the electrical parameters of outer space.

Advances in space exploration have led to the appearance of artificial Earth satellites, including inhabited ones, that solve the problems of researching both the Earth and outer space by radio engineering methods. On the agenda are projects of people visiting the nearest planets and sending spacecraft outside the solar system. These devices will need to be connected. Since the estimated communication ranges can reach millions of kilometers or more, the question arises of the attenuation of a high-frequency electromagnetic field in outer space.

The amplitudes of the electric and magnetic components in a plane wave of the electromagnetic field in a medium with losses are described by the following formulas (V.V.Nikolsky, TNNikolskaya. Electrodynamics and radio wave propagation. M.:URSS, 2012):

$$E=x_{0}A\cdot e^{-az}\cos \left(\omega t-\beta z+\varphi \right)$$

$$H=y_0\frac{A}{|\; |\; |W|\; |\; |}\cdot e^{-az}\cos \left(\omega t-\beta z+\varphi -{\varphi }_w\right)$$

where x ₀ , y ₀ are unit vectors of the axes X and Y;

A is the vector potential;

| W | - the modulus of the wave resistance of the medium;

- погонное затухание (вещественная часть постоянной распространения γ=α+iβ); $$\alpha =\frac{\omega \sqrt{{\epsilon }^{\text{'}\text{'}}{\mu }^{\text{'}\text{'}}}}{c}\cdot \frac{tg\Delta }{2}$$

- linear attenuation (the real part of the propagation constant γ = α + iβ);

z is the wave propagation distance along the Z axis;

ω is the circular frequency;

ε ', μ' are the real parts of the electric and magnetic permeabilities of the propagation medium in the complex representation of ε, μ; c is the speed of light;

t is the time;

φ is the initial phase of the wave at t and z equal to zero;

φ _w is the phase of the wave resistance.

As can be seen from the above formulas, the amplitudes of the electric and magnetic field strengths depend on the exponential coefficients e ^-az , the value of which is determined by the range z and the amount of specific attenuation α.

The coefficient α is determined by the following relationship:

$$\alpha =\frac{\omega }{c}\cdot \frac{\sqrt{{\epsilon }^{\text{'}\text{'}}{\mu }^{\text{'}\text{'}}\cdot }tg\Delta }{2},$$

where ε 'µ' is the product of the material parts of the complex quantities of the electrical and magnetic permeability of the propagation medium,

- тангенс угла потерь, зависящий от частоты, электропроводности среды σ и ее абсолютной и относительной электрической проницаемости среды ε₀ и ε соответственно. $$tg\Delta =\frac{\sigma }{\omega {\epsilon }_0\epsilon }$$

- the loss tangent, depending on the frequency, electrical conductivity of the medium σ and its absolute and relative electrical permeability of the medium ε ₀ and ε, respectively.

The conclusion follows: if the propagation medium has conductivity and σ ≠ 0, then the field amplitudes E and H will decrease exponentially with increasing distance z from the radiation source. This is the phenomenon of attenuation of an alternating electromagnetic field in conductive media that has been well studied and confirmed by practice. Until now, the attenuation of variable electromagnetic fields in outer space has been neglected due to the apparently negligible values of this attenuation in solving practical problems. However, one cannot neglect the fact that the observable part of the Universe is filled with relic radiation, the intense spectrum of which corresponds to a temperature of 2.7 K (TSB, 1969-1978). This fact confirms the validity of the third law of thermodynamics, which leads to the conclusion that it is impossible to carry out such a process, as a result of which the body would cool to a temperature T = 0 K (the principle of the unattainability of absolute 0 temperature, B. M. Yavorsky and A. A. Detlaf. Reference in Physics, Moscow: Nauka, 1965). Relic radiation is associated with the presence of hydrogen atoms in space and their ionization by cosmic rays of various nature of origin and intensity. Thus, it can be argued that in space there are free electric charges that cause the conductivity σ to be zero. The consequence of this is the inequality to zero of the loss tangent and the specific attenuation coefficient α.

Known methods and devices for measuring the electrical characteristics of various environments RF Patent No. 2132550 from 06/27/1999, "Method for determining electrical conductivity and device for its implementation", RF Patent No. 2209425 from 07/27/2003, "Method for the recognition of gaseous substances and device for its implementation."

The closest in technical solution is the RF Patent No. 2051476 dated 12/27/1995 "Method for plasma diagnostics and device for its implementation."

The disadvantage of both analogues and the prototype is that all existing methods do not provide for the measurement of the characteristics of an alternating electromagnetic field in open space.

The purpose of the invention is the determination of the coefficient of specific attenuation of outer space.

This goal is achieved by determining the attenuation of an alternating electromagnetic field in outer space by a probe placed in this medium, by diagnosing the characteristics of the medium under study, the probe being a flat open capacitor shaded from solar radiation by an opaque screen to which high-frequency signals of a fixed frequency are supplied, while receive measurement information from the probe in the form of a loss tangent and permittivity of the medium under study, which allow determining elit coefficient per unit length attenuation space.

The drawing shows a conditional block diagram of an installation for implementing the method. Designations adopted in the drawing: 1 - probe containing an open capacitor; 2 - a screen from solar radiation; 3 - measuring complex. The determination of the coefficient of specific attenuation a is as follows. As shown above, the analytical expression defining this coefficient contains tgΔ, the angle Δ of which is determined by the change in the phase difference between the current and voltage on the plates of the capacitor with the absorbing medium compared with the angle of the phase difference in vacuum equal to 90 °. The angle equal to the phase difference φ _w between the current and voltage on the capacitor plates corresponds to the phase of the wave impedance W. It is related to the angle of electrical loss by the ratio Δ = 2φ _w . Angle measurement φ _w . provides a determination of the value of tgΔ. This is true if the assumption is made that there are no magnetic losses in space inherent to magnetodielectrics, or they are negligible. If this assumption is not fair and there are also magnetic losses, then the result of determining the amount of attenuation should be considered as "attenuation not less than that obtained as a result of the implementation of the proposed method".

In accordance with the accepted assumption about the absence of magnetic losses, we take μ '= μ ₀ .

To determine the coefficient α, it is also necessary to determine the material part of the electric permeability of the propagation medium ε '. For this, the capacitance of the probe capacitor C _k is measured and compared with its capacitance C _{1 of} this capacitor, measured in any other medium with a known electric permeability ε ₁ . The ratio of these capacities is determined by the expression (for known values of s, d, the area of the capacitor plates and the distance between them, respectively):

$$\frac{C_k}{C_{\mathrm{one}}}=\frac{{\epsilon }_k\cdot s}{d}\cdot \frac{d}{{\epsilon }_{\mathrm{one}}\cdot s}=\frac{{\epsilon }_k}{{\epsilon }_{\mathrm{one}}}$$

From here, the dielectric constant of outer space is determined $${\epsilon }_k=\frac{C_k}{C_{\mathrm{one}}}\cdot {\epsilon }_{\mathrm{one}}$$

Since the imaginary part of the complex value of the dielectric constant of space is significantly less than its material part (for this reason, the dielectric constant of space is equated with vacuum), it can be neglected and in this case the material part can be equated to the calculated value ε _k , i.e. ε '= ε _k .

The values of the circular frequency ω used in carrying out the indicated measurements, and the speed of light c are known, and the value of the specific attenuation α is calculated according to the above formula.

Thus, all quantities included in the calculation formula e ^-az for determining the attenuation of an alternating electromagnetic field in outer space are measured and calculated, which makes it possible to determine the attenuation for various distances z.

Claims (1)

A method for determining the attenuation of an alternating electromagnetic field in outer space by a probe placed in this medium by diagnosing the characteristics of the medium under investigation, characterized in that the probe is a flat open capacitor shaded from solar radiation by an opaque screen to which high-frequency signals of a fixed frequency are supplied, while receive measurement information from the probe in the form of a loss tangent and permittivity of the medium under study, which allow determining the coefficient Entent of linear attenuation of outer space.