RU2401492C1 - Wideband turnstile cavity antenna - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: proposed antenna comprises assemblage of N pairs of conducting plates which, when connected, form N slit radiators, assemblage of N vertical posts, top and bottom brackets to form antenna support, as well as power divider and feeders. Said slit radiators allows match with feeder in 15%-frequency band with standing-wave ratio not exceeding 1.05.

EFFECT: rigid design, horizontal polarisation with directional characteristic in horizontal plane approximating to circle, possibility to use as transceiver antenna in UHF and SHF ranges.

12 cl, 17 dwg

Description

FIELD OF THE INVENTION

This invention relates to radio antennas, and more particularly to wideband antenna systems with horizontal polarization of the radiation field having a circular radiation pattern in the horizontal plane, a small standing wave coefficient, 1.15 or less, in a wide frequency band. Such antennas are necessary for the transmission and reception of radio signals, television signals, in blind landing systems for aircraft, in radio navigation beacons and other radio systems.

State of the art

The first turnstile antenna is known, containing two mutually perpendicular horizontal vibrators, fed with a phase shift of 90 ° [P.N. Ramlau, A.A. Pistolkors. Patent for invention No. 17427. - Class 21 a ⁴ , 46 ₀₃ . - Declared. 12/21/1929, No. 60752. - Publ. 09/30/1930. Truskanov D.M. The development of domestic technology of television transmitting antennas. Collection of "Antennas". - M .: Communication. - 1967, No. 2. - Page 5]. The well-known first turnstile antenna has a significant radiation level at large elevation angles, which makes them unsuitable as single emitters for broadcasting and television in the ultra-short wavelength range. The known first turnstile antenna has disadvantages due to the removal of the vibrator arms relative to the vertical axis of the antenna:

- large non-uniformity of the radiation pattern in the horizontal plane, reaching a value of ± 3 dB;

- when constructing the antenna in the decimeter wavelength range, the support with a reasonable electrical size of the diameter does not provide the necessary antenna strength and rigidity;

- low antenna directivity;

- a high level of radiation in the vicinity of the direction of the axis of the support, which when using the antenna as a transmitting television antenna causes a high level of radiation in the technical area of the television station located near the antenna support;

- A complex antenna power system.

The second turnstile antenna is known (B.V. Braude. Plane vibrator. Copyright certificate No. 69974 of the USSR. - Priority 04/12/1946. Publish. 12/31/1947. Braude B.V. New broadband VHF antenna for television. - Radio engineering, 1947, No. 7) containing a vertical support in the form of a pipe, the first, second, third and fourth flat rectangular plates, the first and second feeders, each of which is made on two coaxial cables, a power divider and fasteners. The first and second plates are located in the first plane passing through the axis of the pipe, on opposite sides of the pipe so that one of the edges is parallel to the axis of the pipe and the upper corner point of the plate is connected to the pipe with the formation of the first and second short-circuited slotted transmission lines. The first and second plate essentially serve as the shoulders of the first planar vibrator fed by the first and second slotted transmission lines. The third and fourth plates are located in the second plane passing through the axis of the pipe. perpendicular to the first plane. The third and fourth plates together with the pipe form the third and fourth slotted transmission line supplying the second planar vibrator formed by the third and fourth plates. Each slotted transmission line is driven by a coaxial cable located inside the pipe. In this case, the outer conductor of the cable is galvanically connected to the pipe, and the central conductor through the hole in the pipe is brought out and galvanically connected to the edge of the plate at the lower corner point of the plate. Adjacent slotted transmission lines are powered with a 90 degree phase shift relative to each other. Such antennas were used in our country at the first television stations.

Known second turnstile antenna has the disadvantages:

- large non-uniformity of the radiation pattern in the horizontal plane, reaching a value of ± 3 dB (Erokhin G.A., Chernyshev O.V., Kozyrev N.D., Kocherzhevsky V.G. Antenna-feeder devices and radio wave propagation. Textbook for universities. - M .: Radio and communications. - 1996. P.180);

- when constructing the antenna in the decimeter wavelength range, the support at a reasonable electrical size of the diameter, the physical diameter is small and therefore the support does not provide the necessary strength and rigidity of the antenna;

- the use of large diameter supports leads to unacceptable irregularities in the horizontal pattern.

The above disadvantages are due to the fact that the support is inside the cracks:

- the coefficient of utilization of the antenna surface is small due to the uneven distribution of current over the surface and, as a result, the coefficient of directional action of the antenna is small;

- a high level of radiation in the vicinity of the direction of the axis of the support, which when using the antenna as a transmitting television antenna causes a high level of radiation in the technical territory of the television station located near the antenna support,

- complicated power system.

Known third turnstile antenna (R.W. Masters. Antenna. US patent No. 2480154). The antenna contains a support, four flat plates, four jumpers, a power system. Four flat plates are arranged radially with an interval of 90 ° around a conductive tubular mast, which serves as a support for the antenna. One edge of each plate extends parallel to the mast at a close distance from it. This edge with the help of jumpers is galvanically connected at its extreme upper and extreme lower points to the mast. The edge of each of the plates, located far from the mast, is made with a V-neck. As a result, the width of the plate varies from one eighth of the wavelength in the center of the plate to one fourth of the wavelength at its ends. Two plates located in the same plane represent a dipole of a L-shaped form. Each shoulder is powered by a coaxial cable. The dipoles of the third known turnstile antenna have a greater directional coefficient than the dipoles of the first known turnstile antenna.

However:

- the utilization factor of the antenna surface is less than what can be obtained, for example, with a uniform distribution of current along one coordinate and a cosine distribution of current along another coordinate on the antenna surface;

- under the antenna of the L-shaped vibrators have to increase the diameter of the support. The problem of the diameter of the support is compounded when other antennas, for example, antennas of other channels, need to be positioned higher on the same support. With a large shoulder spacing of the Ж-shaped vibrator, which would have to be applied due to the large diameter of the support, it is no longer possible to provide a uniform radiation pattern in the horizontal plane with an accuracy of 3 dB, which is necessary for uniform coverage of the circular coverage area;

- the antenna has a high radiation level in the vicinity of the direction of the axis of the support. The antenna power system is complex.

Known for the fourth turnstile antenna (O.M. Woodward. Broadband turnstile antenna. US patent No. 3932874), made of four triangular fan-shaped radiating elements placed around a vertical mast. Each emitter is mounted on the mast using two metal brackets having galvanic contact with the emitters at corner points remote from the mast. The radiating elements are powered with equal power with relative phases 0 °, 90 °, 180 ° and 270 °. The known fourth turnstile antenna has a wider operating frequency band than the frequency band of the first, second and third known turnstile antennas, however, it has the above disadvantages of the first, second and third known turnstile antennas.

Closest to the proposed technical solution is the third known antenna, which is accepted by the authors as a prototype.

Disclosure of invention

The aim of the invention is:

- reducing the unevenness of the radiation pattern in the horizontal plane of the antenna with horizontal polarization,

- an increase in the strength and rigidity of the antenna structure,

- an increase in the directional coefficient of the antenna,

- reducing the level of radiation in the direction vertically down,

- simplification of the antenna power circuit,

- providing protection from the influence of adverse meteorological factors on the electrical parameters of the antenna.

The goals are achieved due to the fact that the antenna system containing many pairs of conductive plates (each pair of plates is located in one of N planes, where N≥1), the power divider and transmission lines of electromagnetic energy, additionally contains many M vertical racks, where M≥ 2, N matching devices, upper and lower brackets, while the set of N planes forms a bundle of planes with a vertical axis, the contour of each plate consists of a straight vertical edge with a ledge, upper edge, lower edge ki and rectilinear vertical edge opposite the edge with the shoulder; each plate with a vertical edge with a ledge is aligned with the aforementioned axis of the beam, and the plates are galvanically connected to each other along the lines of their interface with the formation of ledges N cracks; one of the aforementioned transmission lines is connected to each slot, while the outer conductor at the end of each transmission line is galvanically connected to one of the plates in each of the said pairs of plates, and the central conductor is connected to a corresponding matching device galvanically connected to the second plate from the said pair of plates ; transmission lines at their second ends are connected to a power divider; racks are connected to the upper and lower brackets with the formation of the antenna support; the plates are connected to the antenna support.

Introduction to the composition of the antenna an additional set of M vertical racks, where M≥2, upper and lower brackets solves the problem of creating a strong and rigid antenna structure when exposed to wind load. The formation of gaps, as indicated above, allows you to get the radiation pattern in the horizontal plane in a shape close to a circle. The use of plates in the antenna, the vertical size of which is larger than the vertical size of the slots (more than half the wavelength), leads to an increase in the coefficient of directional action of the antenna, to a decrease in the level of radiation in the vertical downward direction, which allows providing environmentally safer conditions on the antenna support located near technical territory of the radio television station.

The introduction of additional matching devices into the composition of the antenna "solves the problem of creating an antenna with VSWR below 1, 15 in the band of several television channels.

The introduction of the above devices together solves the problem of creating an antenna with an input impedance of 50 or 75 Ohms,

- create an antenna capable of emitting signals with a high power level,

- create an antenna with an almost constant input impedance in a wide frequency range, which is important for the quality of the transmitted signal,

- create an antenna with high mechanical strength, provided by the required number of racks and the shape and size of their cross section, which allows you to place other antennas above this antenna, for example antennas for working on other television channels or in other frequency ranges,

- create an antenna, the design of the radiating elements of which provides a constant current connection of all elements with the grounding system of the support on which it is installed,

- create an antenna that provides protection from the influence of adverse meteorological factors on its electrical parameters.

Brief Description of the Drawings

Figure 1 shows the disassembled turnstile antenna with two pairs of plates in accordance with the present invention.

Figure 2 presents the turnstile antenna in assembled form with two pairs of plates in accordance with the present invention.

Figure 3 is a top view of the assembled antenna shown in figure 2.

Figure 4 presents another embodiment of the turnstile antenna in disassembled form, in which the third and fourth, metal plates are made in the form of one flat plate.

Figure 5 shows another variant of the turnstile antenna, in which the plates of the first and fourth, third and second are paired together with the formation of direct spatial dihedral angles.

Figure 6 presents another embodiment of the turnstile antenna, in which the plates are made with a triangular notch.

Figure 7 shows another embodiment of the antenna, in which the plates are made in the form of a lattice of horizontal conductors, the contours of the slots and plates are made of vertical conductors.

On Fig presents a linear antenna array in which slotted turnstile emitters are used as emitting elements.

Figure 9 shows the radiation pattern in the plane of the vector E of the first sample antenna.

Figure 10 shows the radiation pattern in the plane of the vector H of the first sample antenna.

Figure 11 shows the radiation pattern of the second sample of the antenna in the plane of the vector E.

On Fig shows the radiation pattern of the second sample of the antenna in the plane of the vector N.

Figure 13 shows the calculated (solid line) and experimental (dashed line) radiation patterns of the third antenna sample in the plane of vector H at a frequency of 470 MHz.

On Fig shows the calculated and experimental radiation patterns of the third antenna sample in the plane of the vector H at a frequency of 550 MHz.

On Fig shows the calculated and experimental radiation patterns of the third antenna sample in the plane of the vector H at a frequency of 620 MHz.

On Fig presents the dependence of the SWR from the frequency for the slot emitter in the four-element antenna array with a cowl.

On Fig a dashed line shows the radiation pattern of the antenna in the plane of the vector E with four plates, the solid line shows the radiation pattern of the antenna with six plates according to the calculation results.

The implementation of the invention

Turning to FIG. 1, a turnstile antenna 1 with two pairs of plates is shown in accordance with the present invention. Antenna 1 contains the first 2, second 3, third 4 and fourth 5 flat metal plates, four racks 6, 7, 8 and 9, a power divider 10 with an input 11 and with the first 12 and second 13 outputs, the first 14 and second 15 feeders, the first matching device 16, the second matching device 17, the upper and lower brackets (the brackets are not shown in FIG. 1), the cowling (the cowling is not shown in FIG. 1). Each of the plates 2-5 has a vertical edge 18 with a ledge 19, an upper edge 20, a lower edge 21, and a straight vertical edge 22. The plates 2 and 3 lie in the first plane 23, the plates 4 and 5 lie in the second plane 24, orthogonal to the plane 23. The intersection line of 25 planes 23 and 24 is a vertical straight line.

Plates 2-5 are made of a highly conductive material such as aluminum alloy, copper alloy or steel. Perhaps the use of foil dielectric plates. Racks 6, 7, 8 and 9, the upper and lower brackets can be made of aluminum, brass or steel pipes, channels, corners or other rolled products or a high-frequency dielectric. A standard coaxial cable is used as a feeder. Matching devices 16. and 17 are made in the form of segments of a coaxial cable. The power divider is calculated according to well-known formulas given in textbooks on technical electrodynamics or in manuals on microwave devices. The fairing is made of high-frequency dielectric.

The above devices are interconnected as follows (figure 2). The first 2, second 3, third 4 and fourth 5 plates are galvanically connected to each other by edges 18 to form straight dihedral angles 26 with a common straight line 25 - the edge of the dihedral angle, hereinafter referred to as the vertical axis 25 of the antenna. In terms of the resulting device has the shape of a cross (figure 3). The steps 19 on the edges 18 on the first 2 and second 3 plates when the plates are galvanically connected form the first slot 27 with the edges 28 and 29 parallel to the axis 25. The steps 19 on the edges 18 on the third 4 and fourth 5 plates when the plates are galvanically connected form a second gap 30 with edges 31 and 32 parallel to the axis 25. Racks 6, 7, 8 and 9 are made of metal, plates 2-5 are connected to the racks and to the upper and lower brackets with the formation of galvanic contact between the plates and racks, between the plates and the upper and lower brackets.

The outer conductor 33 (FIG. 3) of the first feeder 14 is galvanically connected to the first plate 2, and the central conductor 34 is laid over the slot 27 and galvanically connected to the central conductor 35 of the first matching section of the feeder 16, the outer conductor of which 36 is galvanically connected to the second plate 3. The second end of the first feeder 14 is connected to the first output 12 of the power divider 10.

The outer conductor 37 of the second feeder 15 is galvanically connected to the third plate 4. The central conductor 38 is laid above the slot 30 and galvanically connected to the central conductor 39 of the second matching section of the feeder 17, the outer conductor 40 of which is galvanically connected to the fourth plate 5. The second end of the second feeder 15 is connected with the second output 13 of the power divider 10.

The lengths of the first 14 and second 15 feeders differ from each other by a quarter of the wavelength at the operating frequency. Racks 6-9 are attached to the upper and lower brackets to stiffen the antenna structure. The bottom bracket has holes for attaching the antenna to the mast or tower. In this case, the upper and lower brackets can be made in the form of a cross, disk or other shape.

In another embodiment, the connections of the struts 6-9 are connected to the upper and lower brackets, the plates have galvanic contact with the upper and lower brackets, and a gap is formed between the plates and racks. In another embodiment, the connections of the plate are connected to the racks with the formation of galvanic contact, the racks are connected to the upper and lower brackets, while gaps are formed between the plates and the upper and lower brackets.

In another embodiment of the antenna 1 (Fig. 4), the third 4 and fourth 5 plates are made together in the form of one plate 41, in which said slit 30 is made.

In another embodiment of the antenna 1 (Fig. 5), the first and third plates are made together in the form of a dihedral plate 42, and the second and fourth plates are made in the form of a dihedral plate 43. In the dihedral plates 42 and 43, holes 44 and 45 are made, which are galvanically connected plates 42 and 43 with each other form the above-mentioned slots 27 and 30.

Preferably, the plates 2-5 are in the shape of a rectangle. However, plates of a different configuration are possible. Figure 6 shows an example of the implementation of antennas with plates 2-5 with a triangular notch. Such configurations of plates 2-5 are possible that when they are connected, plates with a shape called a "bat wing" are formed. The plates 2-5 can be made in the form of a lattice of conductors, as indicated in Fig.7.

The antenna operates in transmission mode as follows. The power of the generator supplied to the input 11 (figure 3) of the power divider 10 is divided into two equal parts. In this case, the signals at the outputs 12 and 13 of the divider are in phase with each other. The slot 27 is excited by a segment of the central conductor 34 of the feeder 14 located in the region between the edges 28 and 29. The slot 30 is excited by a segment of the central conductor 38 of the feeder 15 located in the region between the edges 31 and 32.

The slot antenna, implemented by the first 2, second 3 plates and slot 27, forms in the plane orthogonal to the axis 25, the first radiation pattern in the form of a "figure eight". In this case, the maxima of the radiation pattern are directed perpendicular to the plane 23, in which the first 2 and second 3 plates are located.

The slot antenna, implemented by the third 4, fourth 5 plates and slit 30, forms in the plane orthogonal to the axis 25 a second radiation pattern in the form of a figure-eight. In this case, the maxima of the radiation pattern are directed perpendicular to the plane 24, in which the third 4 and fourth plates 5 are located. As a result, in the graphic image, the “eights” displaying the first and second radiation patterns are rotated 90 ° relative to each other in the plane. Due to the fact that the feeders 14 and 15 differ from each other by a quarter wavelength at the operating frequency, the signals emitted by the first and second slot antennas are 90 ° phase-shifted in space. As a result of the addition in space of the signals emitted by the first and second slot antennas, a circular pattern is formed.

Turning now to FIG. 8, a turnstile antenna 46 is shown in accordance with the present invention, which is; essentially a linear vertical antenna array of slotted turnstile emitters. Antenna 46 includes the first 47, the second 48, the third 49 and the fourth 50 plates, the first 6, the second 7, the third 8 and the fourth 9 racks, the upper 51 and lower 52 brackets, a power divider 53 into four directions, four quadrature dividers three-decibel directional couplers 54, 55, 56 and 57, four connecting feeders 58, 59, 60 and 61 of equal length, eight feeders 62-69 of equal length connecting the outputs of said couplers with matching devices. The four feeders 58-61 and eight feeders 62-69 mentioned are made of a standard RF cable.

Each of the plates 47-50 has a vertical edge with four ledges, an upper edge, a lower edge, a straight vertical edge. The first 47 and second 48 plates lie in the first plane, the third 49 and fourth 50 plates lie in the second plane orthogonal to the first plane. The distance between the steps is more than half the wavelength, but less than the wavelength at the operating frequency.

Racks are made of channel. Each of the feeders 62-69 from power dividers 54-57 located below the lower bracket 52, passes upward through a corresponding hole 70 in the lower bracket, laid inside the channel, through the hole 71 in the channel adjacent to the plate, is withdrawn from it and laid along the corresponding plates.

The interfloor power divider 53 is made, for example, based on a coaxial line and a radial waveguide. The presented antenna works similarly to the operation of antenna 1. At the same time, a radiation pattern is formed in a vertical plane, narrower than that of antenna 1.

First antenna sample

The first sample antenna was made in accordance with the present invention. In the description of this and subsequent antenna samples, we refer to the digital designations of Figs. 1-8. The first sample consists of the first 2, second 3, third 4, fourth 5 plates, four racks 6, 7, 8 and 9, a power divider 10 in two directions, two feeders 14 and 15, the first matching segment of the feeder 16, the second matching segment of the feeder 17, upper 51 and lower 52 brackets. As racks, pieces of a standard channel with a section of 40 × 25 mm ^{2 were used} . The upper and lower brackets are made in the form of conductive disks with a diameter of 270 mm. Plates 2-5 and said discs are made of tinned sheet 0.3 mm thick. The layout is made as follows. Two copies of a plate 400 × 210 mm ² in size were made. A slit with dimensions of 275 × 20 mm ^{2 was} cut in the center of each plate parallel to the side 400 mm long. The first copy of the manufactured plate 41 is used in the sample as the third 4 and fourth 5 plates with the second slot 30. To make the first 2 and second 3 plates, the second copy of the manufactured plate was cut in a straight line coinciding with the axis of the slot. The resulting two plates 2 and 3 are soldered to the first instance of the plate 41 with the formation of the second slit 27. As a result, a device having a plan view of a cross is obtained. The dihedral angles 26 formed by the plates are each 90 °. Plates 2-5 are soldered to the upper 51 and lower 52 brackets, to the racks 6-9. To the first plate near the edge 28 of the slot 27, the braid of the first feeder 14 — the RK-50-2-21 coaxial cable — is brazed, in the area immediately behind the edge 28, the outer cable conductor is removed, the central conductor 34 of the coaxial cable 14 is extended into the region of the slot 27 and soldered to the Central conductor 35 of the first matching cable section 16, the outer conductor 36 of which is soldered to the second plate 3. The distance from the place of soldering the cable to the narrow (lower) edge of the slot is 55 mm. To the third plate 4, in the vicinity of the edge 31 of the slot 30, the braid of the second feeder 15 — the RK-50-2-21 coaxial cable — is brazed, in the area immediately behind the edge 31, the outer cable conductor is removed, the center cable conductor 28 is extended into the gap region and soldered to the center conductor 39 of the second matching segment 17 of the cable, the outer conductor 40 of which is soldered to the fourth plate 5. The desoldering places of the first 14 and second 15 feeders to the plates are spaced on opposite sides from the center of the slots. If we count the distance from the narrow (lower) edge of the first slot to the soldering point of the second feeder, then the distance is 220 mm. The first 14 and second 15 feeders, which are used radio frequency cable RK-50-2-21, have an equal length. The lengths of the matching segments 12 and 13, also made of cable RK-50-2-21, are 44 mm. As a power divider 10 in two directions, a 3 dB quadrature directional coupler on coupled strip lines is used, which, as you know, provides for dividing the power into two equal parts and a 90 ° phase shift between the output signals.

Figure 9 shows the normalized experimental radiation pattern of the first sample of the turnstile antenna in the plane of the vector E. The normalization of the diagram is made relative to the mean square signal level in the plane of the vector E.

As can be seen from the graph in Fig. 9, when two slits orthogonal to each other are excited by signals of equal amplitude, 90 ° out of phase, the antenna pattern in the plane of vector E is close in shape to a circle. Deviations of the experimental radiation pattern of the antenna from the circle do not exceed + 1.08 ÷ -1.2 dB.

Figure 10 shows the normalized experimental radiation pattern of the first sample of the turnstile antenna in the plane of the vector N. In figure 10, the angle is counted from the axis 25 of the antenna. The radiation pattern was normalized with respect to the maximum signal level in the plane of the vector N.

Second antenna sample

The second sample of the antenna differs from the first sample in that between the plates 2-5 and channels 6-9, facing the ends of the plates with their wide face, there is a gap of 5 mm.

Figure 11 shows the normalized experimental radiation pattern of the second sample of the turnstile antenna in the plane of the vector E. The normalization of the diagram is made relative to the rms signal level in the plane of the vector E. The deviations of the experimental radiation pattern of the antenna from the circle do not exceed + 1.418 ÷ -2.02 dB.

On Fig shows the normalized experimental radiation pattern of the second sample of the turnstile antenna in the plane of the vector N. Normalization of the radiation pattern is made relative to the maximum signal level in the plane of the vector N.

A comparison of the graphs in Figs. 9-12 shows that the presence of a 5 mm gap between the plates and racks practically does not affect the antenna patterns in the plane of the vector E and in the plane of the vector N.

Third Antenna Pattern

A third antenna sample was made (Fig. 8). The third sample 46 is a linear vertical four-story antenna array of slotted turnstile emitters.

The third sample includes the first 47, the second 48, the third 49 and the fourth 50 plates, the first 6, the second 7, the third 8 and the fourth 9 racks, the upper 51 and lower 52 brackets, an interfloor power divider 53 into 4 directions, four interfloor feeders 58 , 59, 60 and 61 of equal length, four three-decibel quadrature directional couplers 54, 55, 56 and 57, eight feeders 62-69 of equal length, eight matching devices.

The plates 41, 2 and 3 (figure 4) are made of aluminum sheet. The plate 41 has dimensions 2049 × 120 × 2 mm ³ . Plates 2 and 3 have dimensions of 2049 × 59 × 2 mm ³ . The slots have a length of 230 mm, a width of 20 mm, are located at a distance of 475 mm from each other.

As racks 6–9, standard aluminum channels with a section of 30 × 30 mm ^{2 were used} . Channel shelves facing the axis 25 of the antenna. The interfloor power divider 53 into four directions is based on a coaxial transmission line of electromagnetic energy. Feeders 58-61 and 62-69 and matching devices are made of cable RK-50-2-21.

Racks 6-9 are connected to the upper 51 and lower 52 channels and form the antenna support. The plates 41, 2 and 3 are connected to the channels with the formation of galvanic contact. A power divider 53, three-decibel quadrature directional couplers 54-57, and feeders 58-61 are located below the lower bracket 52, to which a hollow cylinder-shaped skirt is attached to protect said devices from adverse weather conditions.

Each RF cable 62-69 is brought up through one of the holes 70 in the lower bracket 52, laid inside the corresponding channel, through the hole 71 in the wide wall of the channel is taken out of it and laid along the corresponding plate. The outer conductor of the cable has galvanic contact with the plate in the vicinity of the first edge of the slot. The central conductor of the coaxial cable is laid over the slot and connected to the central conductor of the corresponding matching segment of the feeder, the outer conductor of which is connected to the plate in the vicinity of the second edge of the slot.

As the experiments showed, the deviations of the radiation pattern in the plane of the vector E from the circle do not exceed ± 1.5 dB.

On Fig.13-15 shows the calculated and experimental radiation patterns of the antenna in the plane of the vector H at frequencies of 470 MHz, 550 MHz and 630 MHz, respectively. As can be seen from the presented graphs, due to the use of a grating of slot emitters, the antenna radiation pattern in the plane of the vector H has a narrower form.

Numerical antenna models

Numerical studies of the effect on matching the feeder with the slot emitter as part of the antenna array of four turnstile slot antennas, constructed similarly to the third antenna sample, were performed. The input resistance of the slot emitter and the standing wave voltage coefficient (SWR) in the feeder are calculated in the frequency range depending on the dimensions of the antenna elements: plate sizes, slot sizes, channel spacers, channel sizes, upper and lower bracket sizes and their distance to the nearest gap, the length of the matching segment of the feeder, the distance between the point of excitation of the gap and the narrow (lower or upper) edge of the gap, the diameter of the fairing. It was assumed that the fairing is made of fiberglass 3 mm thick. At the same time, the problem of emission of a slit was taken into account in a strict electrodynamic formulation, taking into account the influence of all the aforementioned structural elements of the antenna, taking into account the influence of neighboring slits, taking into account the fairing.

Using the obtained patterns in the behavior of the input resistance of the gap and the SWR, depending on the above dimensions, a parametric synthesis of the antenna was performed for operation in a wide frequency range. The dependence of the SWR in the feeder for a single slot in the composition of the synthesized four-story antenna is shown in Fig.16. As can be seen from the graph in Fig.16, the SWR in the frequency range 470-600 MHz does not exceed a value equal to 1.2. Considering the fact that the neighboring slit located in the orthogonal plane has a 90-degree phase shift, compensation of reflected waves will be observed in the power divider, which with an ideal power divider will allow to obtain the SWR of the turnstile slot emitter in the antenna array in the indicated frequency range less than 1.05.

For comparison, the calculation of radiation patterns of an antenna containing two pairs of plates and an antenna containing three pairs of plates was performed. In both antennas, the dimensions of each plate are 400 × 210 mm ² . In the first of the mentioned antennas, the plates, when connected, form four dihedral angles of 90 ° each, two slots. In the second of the aforementioned antennas, the plates form six dihedral angles of 60 ° each, three slots. The amplitudes of all sources exciting the gaps are equal to one volt. In the first antenna, the phases of the sources exciting the gaps differ by 90 ° from each other. In the second antenna, the phases of the sources exciting two adjacent slots differ by 60 ° from each other. The calculated radiation patterns at a frequency of 550 MHz are shown in Fig. 17. The graph corresponding to the radiation pattern with four plates has the form of a dashed line curve. The graph corresponding to the radiation pattern with six plates has the form of a continuous curve.

As can be seen from a comparison of the graphs, the antenna pattern with six plates deviates from the circle by a smaller amount than the antenna pattern with four plates.

The antenna can be used as a transmitting, receiving, or transceiving antenna in VHF and microwave systems in which it is necessary to provide horizontal polarization of the radiation field with a radiation pattern in the form of a circle in the horizontal plane. In particular, such antennas will find application for the transmission and reception of radio signals, television signals, in blind landing systems of aircraft, in aerodrome radio navigation radio beacons and other radio systems.

Claims (12)

1. An antenna system containing many pairs of conductive plates, each pair of plates is located in one of N planes, where N≥1, power divider and transmission lines of electromagnetic energy, characterized in that it further comprises a plurality of M vertical racks, where M≥2, N matching devices, upper and lower brackets, while the set of N planes forms a bundle of planes with a vertical axis, the contour of each plate consists of a straight vertical edge with a ledge, upper edge, lower edge and straight vertical of a flanged edge, an opposite edge with a ledge, each plate with a vertical edge with a ledge is aligned with the beam axis, the plates being galvanically connected to each other to form ledges N slots, one of these transmission lines is connected to each slot, with an external conductor at the end of each the transmission line is galvanically connected to one of the plates in each of the said pairs of plates, and the central conductor is connected to a corresponding matching device galvanically connected to the second plate of the aforementioned of that pair of plates, the transmission line are connected by their second ends to the power divider, strut connected to the upper and lower arms to form the antenna support, a support plate connected to the antenna. 2. The antenna system according to claim 1, characterized in that said plates are connected to said brackets to form a galvanic contact. 3. The antenna system according to claim 1, characterized in that said plates are connected to said racks to form galvanic contact. 4. The antenna system according to claim 1, characterized in that said plates are connected to said racks and to said brackets to form a galvanic contact. 5. The antenna system according to claim 1, characterized in that a segment of the transmission line is used as a matching device. 6. The antenna system according to claim 1, characterized in that a coaxial cable is used as a transmission line of electromagnetic energy, and pieces of coaxial cable are used as matching devices. 7. The antenna system according to claim 1, containing the first and second metal plates lying in the first plane, the third and fourth metal plates lying in the second plane, the first and second planes form 90-degree dihedral angles with a vertical axis, four racks, the first and second coaxial cables and a power divider with an input and first and second in-phase equal-amplitude outputs, while the difference in lengths of the first and second coaxial cables is equal to a quarter of the wavelength at the operating frequency; on the first, second, third and fourth plates at the edges aligned with the axis of intersection of the planes, cuts are made forming the steps on the said edges, the first, second, third and fourth plates are galvanically connected to each other by the edges on which the steps are made, forming in terms of the cross and the main axis of symmetry of the antenna, the steps on the first and second plates form the first slit, and the steps on the third and fourth plates at the junction form the second slit, and the axes of the slots coincide between oh and they form the main axis of symmetry of the antenna, the aforementioned first to fourth plates are connected by vertical straight edges, the outer conductor of the first feeder is galvanically connected to the first plate at a point on the edge of the first slit, and the central conductor is extended into the gap region and galvanically connected to the central conductor of the first matching devices, the external conductor of which is galvanically connected to the second plate, the second end of the first feeder is connected to the first output of the power divider, the external wire the second feeder is galvanically connected to the third plate, and the central conductor is extended into the slot region and galvanically connected to the central conductor of the second matching device, the outer conductor of which is galvanically connected to the fourth plate, the second end of the second feeder is connected to the second output of the power divider. 8. The antenna according to claim 7, characterized in that the first and second racks are located outside the first plane, the third and fourth racks are located outside the second plane, while the said racks are not directly connected to the said plates, the first and fourth racks are connected to the lower and upper brackets. 9. The antenna according to claim 6, characterized in that the first and second feeders are equal to each other in length, and a 3 dB quadrature directional coupler is used as a power divider. 10. The antenna according to claim 1, characterized in that it further comprises a power divider in Q directions, where Q is an integer, Q quadrature directional 3 dB couplers, Q connecting feeders, on the first, second, third and fourth plates are made on each Q cutouts with the formation of Q ledges on one of the edges of each plate, the ledges are located at a distance from each other greater than half the wavelength, but less than or equal to the wavelength in free space at the operating frequency. 11. The antenna system according to claim 1, characterized in that it further comprises a fairing. 12. The antenna system according to claim 11, characterized in that it contains a power divider into 8 directions, 8 feeders, the first, second, third and fourth plates are 4λx4λ (λ is the wavelength), the slots are 0.5λ × 04λ, the slots are located at a distance of one wavelength from each other at the operating frequency, four feeders of the eight feeders mentioned differ in length from the other four feeders by a quarter of the wavelength, aluminum channels with a cross-section of 30 × 30 mm ^{2 are} used as racks, the channels are interconnected with using the upper and lower bracket s and form a support antenna channels located at the corners of a square and a wide side (shelf) turned towards the axis of the cross; each of the eight RF cables from the power divider located below the lower bracket is led up through the hole in the lower bracket, laid inside the corresponding channel, out of the channel through the hole in the wide wall of the channel and laid along the corresponding plate, while the outer conductor of the cable is connected to the plate with the formation of galvanic contact, and the Central conductor is connected to the Central conductor of the matching segment of the feeder, the outer conductor of which is galvanically connected to the other With a plate lying in the same plane as the first plate, the second ends of the cables are connected to a power divider in 8 directions.

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