RU2470426C1 - Phased antenna array element - Google Patents

Abstract

FIELD: physics, radio.

SUBSTANCE: invention relates to elements of microwave and EHF wireless devices. The disclosed phased antenna array element operates on circularly polarised waves. The element includes the following, arranged in series in a housing: a dielectric radiator, a radiator waveguide, a matching waveguide, dielectric insert which is inserted into the matching waveguide, a Faraday-type waveguide ferrite phase shifter with magnetic memory and a reflector. The phase shifter consists of a ferrite bar with a square section on whose lateral surface there is a first current-conducting coating, a magnetisation winding which is wound around the bar and a magnetic conductor encircling the winding. The magnetic conductor is in form of clamps, each lying on each face of the ferrite bar. The reflector has the shape of the cross-section of the ferrite bar and is in form of a section of a below-cutoff waveguide which is open on one end, having a first current-conducting coating on the lateral surface which is common with the ferrite bar. The housing is in form of a thin-walled case. A cut, which is coated with a dielectric strip, is made along the longitudinal axis of one of the faces of the ferrite bar and the reflector in the first current-conducting coating. A second current-conducting coating whose width satisfies a certain ratio is deposited on the outer surface of the strip symmetrically with respect to the cut.

EFFECT: design of a high-technology, small-size element of a phased antenna array with low loss, high-speed operation and low control energy.

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Description

The invention relates to the field of radio engineering of the microwave and EHF ranges, and in particular to the designs of elements of phased array antennas (PAR), and can be used in radar systems with wide-angle electric scanning of the antenna beam.

Currently, there is a real need for waveguide ferrite phase shifters (WFFF) and PAR elements based on them with small transverse dimensions for antenna systems with wide-angle electric beam scanning, working on electromagnetic waves that are polarized in a circle. The creation of such PAR elements for the millimeter wave range is especially relevant, where the development of elements with small transverse dimensions, high speed and low power consumption encounters certain technical difficulties.

Known elements of phased array antennas that perform electrical scanning of the beam. Each of them can be made, for example, in the form of series-connected waveguide-dielectric emitter and a reflective waveguide ferrite phase shifter Faraday type with longitudinal magnetization, with magnetic memory operating on waves polarized in a circle.

In particular, the multi-element headlamp of the Ka-wave range is known (Denisenko V.V., Dubrov Yu.B., Korchemkin Yu.B., Makota V.A., Nikolaev A.I., Tolkachev A.A., Shitikov AM, Shishlov A.V., Shubov A.T. Multi-element phased array phased array of the Ka-wave range. - Antennas, 2005, No. 1 (92), pp. 7-14). For phasing of radiating elements in the PAR, waveguide ferrite phase shifters of the reflective type are used for circularly polarized waves. Each WFWF is made on the basis of a round ferrite rod (FS) with a metallized side surface and one end face, it has several longitudinal magnetization windings of the FS and two magnetic cores.

The known elements of the PAR are inherent in a number of disadvantages. Firstly, there are no integrated elements in this headlamp. The radiating elements are located in the carrier plate common for the PAR, and the WFWF are combined into sublattices of different sizes. The lack of reliable contact between the emitters and phase shifters can lead to a mismatch in the headlamps and an increase in microwave losses. Secondly, the CWFWs have large transverse dimensions, and the antenna array pitch is 1.1λ (λ is the wavelength in free space), which limits the beam scanning sector by angles ± 25 ° from the normal to the PAR opening. Thirdly, the consequences of metallization of FS surfaces are the low speed of the WFWF and the high energy of its control.

Known microwave ferrite phase shifter for phased array reflective type (see patent RU No. 37877, IPC H01Q 21/00, H01P 1/18, publ. 27.05.2008). The microwave ferrite phase shifter comprises a ferrite insert made of microwave ferrite material located inside a control coil providing longitudinal magnetization of the ferrite insert, and a step emitter of the electromagnetic wave with free space connected to the ferrite insert. It additionally contains a cylindrical metal flange and two elongated U-shaped magnetic cores made of ferrite material, introduced by legs from two opposite sides into contact with a ferrite insert in the form of a metallized ferrite rod of circular cross section through rectangular windows of the control coil, which has an internal longitudinal opening for placement ferrite rod (FS). FS is metallized on all sides, with the exception of the inlet end fixed in the hole of the metal flange in its rear end part. The emitter-coordinator with the outer space is made of a dielectric material, for example, of quartz, and inserted into the front of the metal flange, inside of which there is a sleeve, for example, of fluoroplastic in the form of a ring worn on a ceramic disk in contact with the emitter-coordinator and the input end face of the FS .

The known element of the PAR is a functionally complete element of the reflective PAR. In it, a sleeve made of fluoroplastic with a ceramic disk is in direct contact with the end face of the ferrite rod and the end of the emitter-coordinator and is connected to them by an adhesive joint. Known element is characterized by higher performance and lower power consumption. However, the known PAR element is not free from disadvantages. These are, first of all, the relatively large transverse dimensions of the element. A plastic frame of the control coil is used as a supporting element, to which all other parts are glued, and the FS is metallized on all sides, except for the input end fixed in the hole of the metal flange. Such a constructive implementation of the phase shifter leads to a decrease in speed and increase control energy.

A known element of the PAR, which coincides with the claimed solution for the largest number of essential features and adopted for the prototype (see patent RU No. 2323241, IPC H01Q 21/00, Н01Р 1/19, published on 05.27.2008.). A well-known prototype element contains input and output dielectric emitters and a Faraday-type waveguide ferrite phase shifter. The phase shifter consists of a magnetization winding located inside the magnetic circuit and a FS installed inside it in the form of a regular N-faced prism with the number of faces N≥4. The magnetic core is made in the form of U-shaped staples, one on each face of the ferrite rod. The waveguide of the PAR element is formed by a conductive coating of the FS side surface. There are also two waveguides of emitters, two matching waveguides, the diameter of which is greater than or equal to the diameter of the circle described around the FS cross section, and two short circuits with holes along the axis. Each matching dielectric insert is made in the form of a serial coaxial connection of the washer and the rod mounted along the axis inside the hole in the cylindrical shank of the dielectric emitter, which is made of a material with a dielectric constant ε _and = 3.8-4.2. The PAR element is placed inside the housing, made in the form of a metal sleeve connected to the emitter waveguide by an adhesive joint.

This is a small-sized element of the HEADLAND type through passage, strong and resistant to external influences. Based on it, an element of a reflective phased antenna array (OFAR) can also be built.

The disadvantages of the prototype include low speed and high power consumption due to the presence of a conductive coating on the side surface of the FS. The energy spent on controlling the WFWF is spent both on changing the state of the remanent magnetization of the ferrite medium, and to a large extent on overcoming the effect of the "closed loop". This coil in VFVF is a waveguide formed by a conductive coating of the side surface of the FS. With a pulsed magnetization reversal of VFFV, conduction currents appear in this coil, which slow down the process of magnetization reversal and increase the energy consumption from the control system of VFFV. The need to solder FS into waveguide reinforcement also complicates the manufacturing process of the PAR element.

The task of the invention is to ensure the operation of the PAR element in a reflective mode, increasing its speed and decreasing control energy.

The solution of this problem is achieved by the fact that the PAR element operating on circularly polarized waves contains a dielectric emitter sequentially placed in the housing, an emitter waveguide, a matching waveguide, a dielectric insert installed in a matching waveguide, a Faraday type waveguide ferrite phase shifter (VFFV) with magnetic memory and reflector. WFWF consists of a ferrite rod (FS) of square cross section, on the side surface of which the first conductive coating is applied, magnetizing windings wound around the rod, and a magnetic circuit covering the winding. The magnetic core is made in the form of ferrite staples, one on each face of the FS. The reflector repeats the cross-sectional shape of the FS and is made in the form of a transverse waveguide open at one end of the segment and having a first conductive coating of the side surface in common with the FS. The case is made in the form of a thin-walled sleeve. Along the longitudinal axis of one of the faces of the FS and the reflector in the first conductive coating, a cut is made, covered with a dielectric strip, on the outer surface of which a second conductive coating is symmetrical with respect to the cut. The width S of the dielectric strip and the width s of the second conductive coating satisfy the relations:

S> s, mm;

s = (0.8-1.2) · λ / 2√ε, mm;

where λ is the wavelength in free space, mm;

ε is the relative dielectric constant of the material of the dielectric strip.

The element may contain a dielectric frame located between the magnetization winding and the side surface of the FS.

The dielectric emitter can be made of a material with a relative dielectric constant ε equal to 3.5-4.5.

The dielectric insert can be made of a material with a relative dielectric constant ε equal to 9-11, while it can be composite.

FS can be made of a material with a relative dielectric constant ε equal to 13-16.

The reflector may be made of a material with a relative permittivity ε of less than 7.5, for example, of quartz.

The total thickness of the dielectric strip, the first and second conductive coatings may not exceed 0.001λ.

The execution of the cut in the conductive coating of the FS and the reflector coated with a dielectric strip and the second conductive coating of the above width provides increased speed and reduced control energy of the PAR element, since the metallization cut opens the short-circuited coil. The same purpose is the use of an open at the end of the transcendental waveguide as a reflector, since the metallization of its end would close the coil. The first conductive coating on the ferrite core, the layer of adjacent dielectric and the second conductive coating of its outer surface form a transmission line similar to a microstrip. The boundary of the second conductive coating forms a gap in this line. At a distance Λ / 4 from this boundary, the resistance between the first and second conductive coatings is made equal to zero. Here Λ is the wavelength in a homogeneous medium with dielectric constant of the dielectric strip (ε), i.e. Λ = λ / √ε. This is equivalent to shorting the second conductive coating on the dielectric strip to the first conductive coating of the ferrite core at the point of its cut. Since the cut is thin and the strip of the second metal coating passes on both sides, according to the microwave signal, the edges of the cut are interconnected. As a result, the microwave signal propagates inside the square ferrite rod in the same way as if there were no cut in its metallization, i.e. the phase velocities of the orthogonal modes remain the same, and the sum of these modes, 90 ° out of phase, forms its own circularly polarized wave of the Faraday phase shifter. The width of the second conductive coating is less than 0.8 · λ / 2√ε, as well as the increase in the width of the second conductive coating is greater than 1.2 · λ / 2√ε, worsens the effect of closing the edges of the section. The accuracy with which this parameter must be maintained decreases with decreasing dielectric layer thickness, since the impedance of the aforementioned transmission line decreases.

To ensure the operation of the PAR element in the reflective mode, an electromagnetic wave reflector is installed at the output of the VFFV.

The element may contain a dielectric frame located between the magnetization winding and the side surface of the FS. The thickness of the walls of the frame is selected as minimal as possible to ensure a guaranteed gap between the winding wire and the back of the bracket of the magnetic circuit.

The presence of distinctive features allows us to conclude that the present technical solution meets the condition of patentability “novelty”.

The present invention is illustrated in graphic materials, where:

figure 1 shows a longitudinal section of the inventive element HEADLIGHTS;

figure 2 shows a cross section at the location of the shoes of the ferrite staples along AA of the PAR element shown in figure 1;

figure 3 shows a cross-section on an enlarged scale FS with a longitudinal section in a conductive coating.

Figure 1-3 indicates: 1 - dielectric emitter, 2 - emitter waveguide, 3 - matching waveguide, 4 - dielectric insert, 5 - FS, 6 - magnetization coil frame, 7 - magnetization winding, 8 - ferrite bracket, 9 - ferrite bracket shoe, 10 - reflector, 11 - first conductive coating, 12 - dielectric strip, 13 - second conductive coating, 14 - magnetization winding leads, 15 - headlight element housing, 16 - dielectric holder-holder, 17 - longitudinal section in the first coating.

The PAR element works as follows. When an electromagnetic wave polarized in a circle is incident on the headlamp (not shown), from the headlamp irradiator (not shown) or from free space, an electromagnetic wave is received at the input of waveguide 2 of dielectric emitter 1. 1, a wave of type H _{11 is} excited, from its output it enters the input of a matching waveguide 3 with a dielectric insert 4 and also excites a wave of type H _{11 in it} . From the output of the matching waveguide 3, the electromagnetic wave enters the WFVF of the PAR element, which includes the FS 5, the magnetization winding 7 with terminals 12 and the magnetic circuit in the form of 4 ferrite brackets 8. In this case, a H ₁₀ ^kr wave is excited in a metallized FS 5, which is a superposition of waves H ₁₀ and H ₀₁ , 90 degrees out of phase. Since the FS has a square cross section, such a superposition is a natural wave and remains with it during longitudinal magnetization of the FS. The H ₁₀ ^kr wave excited at the input of FS 5 propagates along FS 5, reaches the transcendental waveguide (reflector 10), is reflected from it, propagates in the opposite direction, sequentially passes FS 5, matching waveguide 3, waveguide 2 of radiator 1, and DI 1 is emitted into free space. The phase of the re-emitted element of the PHAR of an electromagnetic wave polarized in a circle depends on the wavelength λ, the dimensions of DI 1, waveguides 2 and 3, FS 5, reflector 10, and also on the parameters of the materials DI 1, dielectric insert 4, FS 5 and reflector 10.

An additional change in the phase of the reradiated electromagnetic wave, for example, within Δφ = 0 ° -360 °, is discretely or continuously carried out in the WFWW by changing the parameters of the FS 5 ferrite medium during its longitudinal magnetization. A longitudinal magnetization field is created in FS 5 by a magnetization winding 7, fed through the terminals 14 from the PAR beam control system or from a power source (not shown in the figures). The presence of magnetic cores 8, when their heels are firmly adjacent to FS 5, preserves the magnetization of SF 5 even when the current is turned off in winding 7 due to the hysteresis of the ferrite material FS 5 and magnetic cores 8, i.e. WFWP phase shift control in magnetic memory mode.

The implementation of the cut 17 in the conductive coating 11 of the FS 5 and the reflector 8, coated with a dielectric strip 12 symmetrical with respect to the cut and the second conductive coating 13, improves the response time and reduces the control energy of the PAR element, since the metallization cut opens a short-circuited turn. The same purpose is served by the absence of metallization of the end face of the transcendental waveguide of the reflector 8, since it would close the loop. The first conductive coating 11 on the FS 5, the layer of the adjacent dielectric 12 and the second conductive coating 13 of its outer surface form a transmission line similar to a microstrip. The boundary of the second conductive coating 13 forms a gap in this line. At a distance Λ / 4 from this boundary, the resistance between the first and second conductive coatings is made equal to zero. Here Λ is the wavelength in a homogeneous medium with dielectric constant of the dielectric strip (ε), i.e. Λ = λ / √ε. With the width of the second coating s = Λ / 2 and its symmetrical location relative to the cut 17 according to the microwave signal, the second conductive coating 13 is closed to the first conductive coating 11 in the place of the cut 17. Since the cut is thin by the microwave signal, the edges of the cut 17 are interconnected . As a result, a wave of type H ₁₀ ^cr distributed file system, without changing its structure. The accuracy with which the parameter s must be maintained decreases with decreasing dielectric layer thickness, since the impedance of the aforementioned transmission line decreases. For the thickness of the dielectric strip 12 within 3–5 μm, a change in the width of the second conductive coating 13 by more than 20% of the value λ / 2√ε, both smaller and larger, worsens the effect of closing the edges of the section, which leads to an unacceptable increase in losses of the WFWF.

To ensure the magnetic memory mode, the staples of the magnetic circuit 8 with their shoes 9 should be pressed against the FS with minimal gaps. Therefore, the total thickness of the layers 11, 12 and 13 of the coating should not exceed 0.001λ. The total cross-sectional area of staples 8 should be 10-20% larger than the FS cross-sectional area.

The presence of the frame 6 is allowed if its use does not cause an excessive increase in the transverse dimensions of the WFWF.

The dimensions of the dielectric emitter 1 are selected from the condition of matching the PAR element with free space or with the waveguide of the measuring path.

The proposed PAR element is characterized by the simplicity of manufacturing individual parts and blocks and the assembly of the device as a whole. In its manufacture can be used normalized, commercially available materials, adhesives and processes. The waveguide 2 of the emitter 1, the matching waveguide 3, the housing 15 of the PAR element is a body of revolution, which can be easily manufactured on high-performance equipment. The waveguide 2 of the emitter 1 and the matching waveguide 3, it is advisable to produce in the form of a single part in the form of a glass, in the bottom of which a square window is cut down.

The dielectric emitter 1 can be made, for example, of a composite material (microwave ferrites and dielectrics / Prospect. - St. Petersburg: OJSC "Magneton Plant, 2001. - 20 s.) With a relative dielectric constant ε _and = 3,5-4, 5 and is made by casting, pressing or machining. In the same way, composite materials (microwave ferrites and dielectrics / Prospect.-SPb .: OJSC Magneton Plant, 2001. - 20 p.) Can be used to produce a dielectric insert 4 and a magnetization winding frame 6 7.

For the manufacture of FS 5 and ferrite staples 8, normalized ferrite materials can be used (microwave ferrites and dielectrics / Prospect. - St. Petersburg: OJSC Magneton Plant, 2001. - 20 p.), For example, for the manufacture of a phased array phased element - ferrite grade 1SCh12. The simplicity of the shape and seating surfaces of these parts makes it possible to use the widely used flat diamond grinding process in their manufacture.

The first conductive coating 11 can be applied both by electroplating and by vacuum deposition. The incision 17 in the first conductive coating 11 may be made by a laser. The application of the dielectric strip 12 and the second conductive coating 13 can be carried out by vacuum spraying.

The assembly of the inventive PAR element is advisable to carry out by gluing the individual parts using normalized adhesives. In particular, for gluing the waveguide 2 of the dielectric emitter 1, the matching waveguide 3 and the housing 15, the housing 15 and the plug 16, as well as the plug 16 and the reflector 10, in the case of their manufacture as separate parts, VK- epoxy adhesive can be used 9. For the adhesive matching waveguide 3 and FS 5, an EK-S brand electrically conductive adhesive should be used, which is used during installation operations in the manufacture of electronic products and can withstand thermal cycling in the temperature range from -60 to + 85 ° С.

To assemble the inventive element PAR, there is no need to develop special conductors and devices. All parts, with the exception of the ferrite block (formed by FS 5 with reflector 10, coil 7, frame 6 and magnetic circuits 8), are bodies of revolution, and their axial alignment is ensured by the selection of tolerances on the dimensions of the parts during their manufacture. The alignment of the ferrite block occurs by inserting the FS into the square window of the matching waveguide 3. In order to increase the resistance of the PAR element to atmospheric influences, in addition to the adhesive joints of individual parts, the dielectric emitter 1, dielectric insert 4 and the ferrite block can be coated with moisture-resistant varnish. To seal the device, the holes for the terminals 14 of the magnetization winding 7 can be filled with sealant.

With the claimed structural embodiment, the PAR element is a solid and rigid structure, resistant to external shock and vibration mechanical stresses. The proposed PAR element is structurally simple, technologically advanced, its manufacture is characterized by low labor intensity and low cost. To create it in the conditions of mass production, there is no need to develop complex technological devices and use expensive technological processes characteristic for the manufacture of the headlamp element adopted as a prototype.

Thus, the practical implementation of the proposed PAR element is not in doubt.

The proposed PAR element can be used as part of a multi-element phased antenna array, the conclusions of its magnetization winding are connected to the beam control system of the PAR (not shown).

The technical result consists in creating a high-tech small-sized element of the PAR, with low losses, high speed and low control energy, easy to manufacture and assemble, durable and resistant to external climatic and mechanical influences.

The effectiveness of the proposed technical solution was tested experimentally when creating elements of the phased array of the millimeter wave range in the frequency band of a rectangular waveguide with a cross section of 7.2 × 3.4 mm ² . The experimental sample of the PAR element has a diameter D _{e of} not more than 0.68λ, which allows it to be used to create flat reflective PARs with wide-angle electric scanning of the beam when it deviates from the normal to the opening of the PAR until 45 ° -50 °.

The phase shifter of the PAR element creates an adjustable phase shift Δφ = 0 ° -400 °, the maximum losses introduced by it do not exceed 1.5 dB, while the maximum rephasing time is not more than 20 μs, and the average control energy does not exceed 15 μJ.

Claims (9)

1. The element of the phased antenna array (PAR), operating on circularly polarized waves, containing a dielectric emitter sequentially placed in the housing, an emitter waveguide, a matching waveguide, a dielectric insert installed in a matching waveguide, a Faraday type waveguide ferrite phase shifter (VFFV) with magnetic memory and reflector; WFWF consists of a ferrite rod (FS) of square cross section, on the side surface of which the first conductive coating is applied, magnetizing windings wound around the rod, and a magnetic circuit covering the winding, the magnetic circuit is made in the form of ferrite staples located one on each face of the FS, the reflector repeats the cross-sectional shape of the FS and made in the form of an open at one end of the segment of the transcendental waveguide having in common with the FS the first conductive coating of the side surface, the housing is made in the form of a walled sleeve, while along the longitudinal axis of one of the faces of the FS and the reflector in the first conductive coating, a cut is made, covered with a dielectric strip, on the outer surface of which a second conductive coating is symmetrical with respect to the cut, and the width S of the dielectric strip and the width s of the second conductive coating satisfy the relations :
S> s, mm;
s = (0.8-1.2) · λ / 2√ε, mm;
where λ is the wavelength in free space, mm;
ε is the relative dielectric constant of the material of the dielectric strip. 2. The element according to claim 1, characterized in that it contains a dielectric frame located between the magnetization winding and the side surface of the FS. 3. The element according to claim 1, characterized in that the dielectric emitter is made of a material with a relative dielectric constant ε equal to 3.5-4.5. 4. The element according to claim 1, characterized in that the dielectric insert is made of a material with a relative permittivity ε of 9-11. 5. The element according to claim 1, characterized in that the dielectric insert is made integral. 6. The element according to claim 1, characterized in that the FS is made of a material with a relative dielectric constant ε equal to 13-16. 7. The element according to claim 1, characterized in that the reflector is made of a material with a relative dielectric constant ε less than 7.5. 8. The element according to claim 7, characterized in that the reflector is made of quartz. 9. The element according to claim 1, characterized in that the total thickness of the dielectric strip, the first and second conductive coatings does not exceed 0.001λ.

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