RU2627973C1 - Device for active control by reflected radio emission - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: device is a set of electrical circuits in an alternating electromagnetic field, made in the form of flat electrical conductors located in layers, each of which is closed at its ends through control devices with active resistance, electrical capacitance and wave dimensions of circuits that change their absorption, resonance tuning frequency and wave dimensions, respectively. Each electrical circuit is an elementary antenna designed to receive electromagnetic waves (EMW) and their further controlled absorption. The control signals of the device allow modulating the amplitude, spectrum, phase and polarization of the reflected EMW.

EFFECT: electric control of the electromagnetic wave absorption independently on different sections of the protected surface of objects, control of the directional pattern and polarization of reflected electromagnetic waves, modulation and fragmentation of reflected signals.

18 cl, 14 dwg

Description

The invention relates to absorbers of electromagnetic waves (EMW) in the microwave range and can be used for controlled changes in the radar visibility of the protected surfaces of objects for various purposes, as well as when equipping shielded rooms and anechoic chambers.

Also, the invention will allow you to electrically control the magnitude of the absorption of EMW Radio Absorbing Coating (RPP) independently on different parts of the protected surface of the objects; expand the frequency range; actively generate a radiation pattern for different radar angles of incidence; create masking and distorted reflected signals from the protected surfaces, control the polarization of the reflected electromagnetic waves.

It is known “Device for the radio masking of reflective surfaces”, patent RU 2403658, 2008, consisting of a layer of an electrically conductive base, a layer of a dielectric and an electrically conductive shielding layer made according to a certain topology.

During operation of the device, the four-terminal compensation links provides mutual compensation of bias currents flowing under the influence of an external electromagnetic field between one of a pair of shielding pads and a neutral pad and between another shielding pad and the same neutral pad.

This device has a complex structure, does not provide satisfactory absorption of electromagnetic waves and does not provide for the possibility of electrical control of the absorption of electromagnetic waves.

Closest to the proposed is the "Electromagnetic wave absorber", RU 2400883, in which EMW are scattered on a radar absorbing filler in the form of ceramic plates coated with a film resistive layer. The dimensions of the ceramic plates and the characteristics of the resistive layer are selected from the conditions for ensuring broadband matching.

The said device does not create an acceptable absorption of electromagnetic waves on large surfaces of objects and does not provide for the possibility of electrical control of absorption.

The purpose of the present invention is the electrical control of the magnitude of the absorption of electromagnetic waves independently on different parts of the protected surface of objects; radiation pattern control and polarization of reflected electromagnetic waves; creating modulation and fragmentation of the reflected signals.

The proposed "Device for the active control of reflected radio emission" is a set of electrical circuits made in the form of flat electrical conductors, closed at their ends through Control Devices (UE) with active losses and electric capacity and located in layers along the surface of the device facing the EMW source.

Each such electrical circuit is an elementary antenna with a resonant frequency and wave dimensions that are consistent with the frequency and length of the incident EMF and is designed to receive EMF and their further absorption.

The above disclosure of the present invention is not limited to each described example or any implementation thereof. The following description and drawings provide more detailed explanations of the described examples and do not limit the various modifications of the present invention that can be implemented within the scope of its distinguishing features.

The present invention is illustrated by the following figures.

In FIG. 1-6, flat conductors of circuits of various shapes are shown, connected to control devices of the loop resistance UU-R and the capacitance of the UU loop. C: FIG. 1 - a spiral in the shape of a circle; FIG. 2 - a spiral in the form of a square; FIG. 3 - square meander; FIG. 4 - a meander in the form of a rectangle; FIG. 5 - a form with one large wave size; FIG. 6 is a shape with one large wave size, forming a flat angle.

In FIG. 7-12 shows the inclusion of a control device for matching the wave sizes of the control unit. Rconcord of electrical circuits for parallel and serial control methods. Thickened lines conventionally show the conductors of these circuits.

In FIG. 7 shows the inclusion of the U.Rsogl for a parallel method of controlling the coordination of the wave sizes of the contours. I, II, III, IV, I + II, III + IV, I + IV, II + III, I + II + III + IV - a series of connected electrical circuits.

In FIG. Figure 8 shows the change in the wave size of the contours at Rsign = 0, i.e. in case of short circuit. I, II, III, IV, I + II, III + IV - the resulting series of connected electrical circuits.

In FIG. Figure 9 shows the change in the wave dimensions of the contours at Rsoc = ∞, i.e. when the circuit breaks. I + III, II, IV, I + III + II, I + III + IV, I + III + II + IV - the resulting series of connected electrical circuits.

In FIG. 10 shows the inclusion of U.Rsogl for a sequential method of controlling the coordination of the wave sizes of the contours. I, II, III, IV, I + II, III + IV, II + III, I + IV, I + III, II + IV, I + II + III, I + II + III + IV - a series of connected electrical circuits .

In FIG. Figure 11 shows the change in the wave size of the contours at Rc = 0, i.e. in case of short circuit. I, II, III, IV - the resulting series of separate and independent from one another electrical circuits.

In FIG. Figure 12 shows the change in the wave size of the contours at Rsogl = ∞, i.e. when the circuit breaks. I + II + III + IV - the resulting series of interconnected electrical circuits.

In FIG. 13, three contours are shown, each with one large waveform size, oriented orthogonally along the coordinate axes.

In FIG. 14 shows a device mounted on a protected side surface of an object. In this case, the lateral surface of the object is divided by the EMB absorbing fragment B into two reflecting EMF fragments A and B. The contours of the fragments A, B, and C have large wave sizes. The absorbing contours of fragment B are indicated by black squares; the reflecting contours of fragments A and B are indicated by squares without filling. Devices for controlling the resistance, capacitance, and wave dimensions of circuits are not shown.

Let us agree that the shape of the electrical circuit is the shape of the surface area of the layer, which is occupied by the flat conductors of this circuit along with the electrically insulating gaps between them.

We will call a contour with linear dimensions of the form - length l and width w, contour

- with large wave sizes (matched sizes) if l, w are greater than or equal to a quarter of the smallest wavelength λ in the operating range, i.e. l, w≥λ / 4;

- with small wave sizes, if l, w is much less than a quarter of the smallest wavelength A in the operating range, i.e. l, w << λ / 4.

The device operates as follows. Electromagnetic waves incident on the surface of the device and induce EMF in the flat electrical circuits-inductances located on it. The electrical circuits include control devices for the resistance, capacitance and wave dimensions of the circuit, respectively changing the absorption of the incident electromagnetic field, the tuning frequency of the circuits and the matching wave sizes of the circuits. These control devices can be included in the circuit in series, parallel or mixed with each other.

The electric resistance control device УУ.R included in each circuit changes the magnitude of the active electric losses in the circuit, which leads to a change in the magnitude of the emf induced in it and, consequently, in the magnitude of the EMF absorption.

A single layer with contours may not be enough to obtain the necessary absorption of electromagnetic waves. To increase the total absorption of EMW device, additional layers with contours are placed along the first layer. In a device with several layers, each elementary electric circuit together with the control unit in each layer contributes its share to the total EMF losses generated by the device, and the shape of the contours and their location along the protected surface of the object are selected so that the electromagnetic field can fall on the protected surface only through all layers with contours.

Since the conductors of the electric circuit and the controlled active resistance included in it do not have frequency-selective properties, with a constant control signal they do not distort the spectrum of the transmitted or reflected electromagnetic wave.

The control device included in the electric circuit can be a controlled variable resistance of low power, made, for example, on the basis of a Field Effect Transistor (PT). When the voltage of the control signal at the gate of the PT changes, the resistance in the drain – source circuit included in the circuit can vary from units of ohms to hundreds of megohms, thus controlling, over a wide range, the absorption of electromagnetic waves in the circuit.

The capacity control device УУ.С, included in each circuit, is intended for its tuning to the frequency of the incident EMW. Such a control device can be implemented, for example, based on a tunnel diode, varicap or varicond, changing its capacitance under the action of the applied control voltage.

The control device for matching the wave dimensions of the circuit УУ.Rсогл, is intended for matching the wave dimensions of the circuit with the length of the incident EMW, see Fig. 7-12. In particular, the wave dimensions of the contours can be changed to a nonreflective electromagnetic wave antiresonant wavelength, i.e. to the series l, w = (2n-1) * λ / 4, where n is the number of half-waves of the working frequency of the electromagnetic wave, laying on the linear dimensions of the shape of the contour l, w.

U.R.sogl can be included as a common, at least in two electrical circuits, see Fig. 7, FIG. 10.

The zero common resistance for several circuits, Rsign = 0 makes them independent and separate with smaller wave sizes, see Fig. 8, FIG. eleven.

The infinitely large common resistance for two or more circuits, the resistivity Rcogl = ∞ corresponds to a break in the connection of the circuits through such a resistance and to an increase in the wave size of the formed electrical circuit due to the addition of the wave sizes of the initial circuits, see Fig. 9, FIG. 12.

The value of the total active resistance Rsocl, which differs from its extreme values of 0 or ∞, leads to a dependence of the magnitude of the absorption of the electromagnetic wave by the circuit and its wave dimensions.

Depending on the method of switching on the control device for matching the wave sizes of the UU.Rconsign, two main ways of controlling the matching of the wave sizes of the contours are possible: parallel and serial.

In the parallel control method shown in FIG. 7, the only common resistance Rcondition is included in three or more circuits.

Rsign = 0 means a short circuit of this connection of circuits and the formation of a group of independent circuits with selected wave sizes, see Fig. 8.

Rset = ∞ means breaking the connection of the circuits through the total resistance, leading to the formation of a group of interconnected circuits with different wave sizes larger than when Rset = 0, see Fig. 9.

In the sequential control method shown in FIG. 10, each common resistance Rcondition is included in only two circuits. Its short circuit at Rc = 0, see Fig. 11 leads to the separation of adjacent (adjacent) loops, and a break at Rsogl = ∞ leads to the unification and increase in the wave dimensions of these loops, see FIG. 12.

To reduce the number of wave sizes of the contours, a number of their wave sizes can be selected based on the possibility of obtaining any larger wave size using the minimum number of circuits of a smaller wave size.

The control device for matching the wave dimensions of the UU.R circuit, as well as U.R, can be performed, for example, in the form of an alternating resistance of low power based on a field-effect transistor or on the basis of a key actuating element (thyristor, relay, etc.), whose resistance can take two extreme values: 0 or ∞.

Radio elements of the control unit UU.Rsogl can be located in the cutouts made for them in the coating; along the side surface of the coating; on remote sites under or above the surface. The radioelements can be connected to the flat conductors of the circuits by an electrically conductive adhesive.

The number of control signal lines for selecting the address of the circuits and control signals on the УУ.R, УУ.С and УУ.Rсогл can be reduced by using a digital control line.

Control devices should have small wave sizes, which can be achieved using a specialized LSI containing all the radio elements of the control device.

Conductors-inductances of electrical circuits are made of a material with a low active resistance, for example, silver, copper, aluminum, and, if necessary, with an increased thickness, which will expand the range of regulation of the absorption of the circuit by the control device. Conductors can be sprayed with metal directly on a dielectric surface, on a dielectric film with an adhesive coating, as well as by drawing through a mask or stencil with electrically conductive paint or paste.

The contours are made in the form of flat conductors paths in the form of a round or square spiral, meander, etc. with a shape generally having large wave dimensions, see FIG. 1-4. This makes the contours reflective (noticeable) for EMW in the operating frequency range of the device.

To obtain greater absorption of electromagnetic waves, the contours with the same shape in neighboring layers can be shifted one relative to another so that the electromagnetic waves intersect as many of them as possible from any direction of their fall. For the same purpose, the shape of the contours and the width of their conductors can be selected different in different layers. The electrical insulating gaps between the conductors, both inside the shape of each circuit and between adjacent circuits, must have a small wave size in the operating frequency range.

Conductors of electrical circuits can be coated, for example, ferromagnetic. If such a coating has low losses, then it enhances the sensitivity (inductance) of the circuit to EMW falling on it. If the losses of the ferromagnetic coating are large, then they are summed up with the losses in the circuit created by the active resistance of the control device and introduce additional attenuation into the reflected electromagnetic wave.

All or some of the circuits may have common signal connection points. At the same time, such electrical conductors, for example, as control lines, connections of common points of circuits and power conductors UU, can be located in separate layers.

All or some UUs may also have common connection points, for example, for connecting electrical power.

A signal can be introduced into the signal reflected from the surface to be protected, see FIG. 5. For this, one size of the shape of the contour - the length l, is performed with large wave sizes, ie l≥λ / 4, and the other, the width w, is small, i.e. w << λ / 4. In a polarized incident EME, the shape of the contour with large wave sizes will produce a larger reflected signal than the shape with small wave sizes.

The shape of some contours with their large wave size can form a flat angle, for example, orthogonal, see FIG. 6. This form has two reflection patterns that coincide with the two directions of incidence of the polarized electromagnetic wave.

Several contours, each with one large wave size, can be oriented unidirectionally by them and form a flat antenna array. The radiation patterns of the reflected signals from such a planar array of contours are added up, and the sensitivity of the circuits to polarized waves increases.

The polarization of the reflected electromagnetic wave can be arbitrarily changed. For this, at least three planar contours, each of which has one large wave shape size, must be oriented with such dimensions at an angle to one another, for example, orthogonally, see FIG. 13.

Three reflected signals from these circuits, corresponding to three orthogonal vectors, determine the polarization of the reflected electromagnetic wave, and the resulting vector formed by these vectors will give direction to the maximum radiation pattern of the reflected signal.

From the signals to the control devices, the absorption at any of the three orthogonal sizes of the shape can be chosen so that the resulting three-dimensional absorption vector has a given direction.

In this case, the polarization of the reflected electromagnetic wave can be selected maximum in any selected direction, regardless of the polarization of the incident electromagnetic wave.

With the help of UE, it is possible to fragment EMW reflected from the protected surface of the object, see Fig. 14. For this purpose, on its protected surface facing the EMW source, by choosing the control signals of adjacent contours, for example, a fragment B intersecting this surface with reduced EMF reflection and dividing the entire reflecting surface into two fragments A and B of a given shape and area is created. According to the reflected electromagnetic signals, such a protected object will be perceived as two separate objects A and B, the reflection value of which can be controlled independently.

With the help of UE, it is possible to distort the spectrum of the reflected signal on the entire protected surface of the object or its fragments, for example, A and B in FIG. 14. For this, a control signal with a spectrum satisfying the requirements of distortion efficiency is supplied to the control line of the U.R. of the contours of these fragments.

With the help of the UE, it is possible to distort the phase of the reflected signal from all or individual parts of the surface of the protected object. For this, a signal with a period coinciding with the period of the incident electromagnetic wave but changing its absorption on a part of the signal period of the reflected electromagnetic wave, for example, at the leading edge of the reflected electromagnetic wave, for example, according to the selected control algorithm (periodicity) of the generated interference, is applied to the control line of the control unit of the corresponding loops.

The device can be used both for shielding an object, located both in front of its protected surface, and to reduce the reflection of the object, being fixed on its protected surface.

,

и т.д. длины волны. В этом случае, устройство позволяет внести потери как в падающую на него прямую ЭМВ, так и в пришедшую на обратную его сторону отраженную волну от защищаемой поверхности объекта.To increase the absorption of electromagnetic waves at individual frequencies of the operating range, the device can be located from the surface to be protected at a distance multiple of

,

etc. wavelengths. In this case, the device allows you to make losses both in the direct EMW incident on it, and in the reflected wave that came to its opposite side from the protected surface of the object.

Claims (18)

1. Device for active control of reflected radio emission, containing electrical circuits in an alternating electromagnetic field, characterized in that the electrical circuits are made with flat conductors located in at least one layer, and resistance control and capacitance control devices are included in the circuit of the electrical circuits. 2. The device according to claim 1, characterized in that at least some of the electrical circuits are made of material with low active losses. 3. The device according to claim 1, characterized in that at least some of the electrical circuits differ from other circuits in the thickness of their conductors. 4. The device according to claim 1, characterized in that at least some of the electrical circuits differ from other circuits in their shape. 5. The device according to claim 1, characterized in that the mutual projections of the forms of at least some of the electrical circuits in different layers do not coincide. 6. The device according to claim 1, characterized in that at least some of the electrical circuits differ from other circuits in the width of their conductors. 7. The device according to claim 1, characterized in that at least some of the electrical circuits are made of a material different from the material of other circuits. 8. The device according to p. 1, characterized in that at least some of the conductors of the electrical circuits have conductive coatings of materials different from the material of the conductors of other electrical circuits. 9. The device according to claim 1, characterized in that at least some of the electrical circuits have common electrical connection points. 10. The device according to p. 1, characterized in that at least some of the contours are shaped with one large wave size. 11. The device according to p. 10, characterized in that the shape of at least some of the contours forms a flat angle. 12. The device according to p. 10, characterized in that at least two circuits with large wave dimensions of their shape are located at an angle between each other. 13. The device according to paragraphs. 10, 11, 12, characterized in that the large wave dimensions of the shape of at least some of the contours are oriented in the same direction and form a flat lattice. 14. The device according to claim 1, characterized in that at least some of the electrical circuits are interconnected via common resistance control devices. 15. The device according to claim 1, characterized in that at least some control lines of the control devices are located in separate electrical insulating layers. 16. The device according to claim 1, characterized in that the control signals supplied to the control device modulate the absorption value of the reflected electromagnetic wave. 17. The device according to claim 1, characterized in that the control signals supplied to the control device modulate the phase of the reflected electromagnetic wave. 18. The device according to claim 1, characterized in that the same absorption is created by at least two adjacent electrical circuits.

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