RU2504054C1 - Antenna for probing ionosphere - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: antenna for probing the ionosphere is in form of two rhombi that cross in orthogonal planes, having side length of 58 m for one rhombus and 26 m for the other rhombus, said rhombi being suspended on a 32 m support mast made of composite material which acts as the main diagonal of the rhombi, and two pairs of auxiliary 9 m masts for suspending second corners of the rhombi, guylines for guying mechanical attachment of the mast made of polymer material and cores of current-carrying cables of the rhombi, located on the edge of a cylinder as radiators of the antenna, loaded by a common resistance which is matched for the traveling wave mode in radiators, connected to a multi-beam earthing conductor, made on a parallel circuit for the mirror counterweight mode.

EFFECT: making a broadband antenna which operates in the entire ionosphere probing frequency band.

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Description

The invention relates to radio engineering and can find application in the field of measurements of geophysical fields of the Earth and communication systems.

Constant monitoring of the electron concentration of the layers of the ionosphere is an important task in space, seismology, storage and transmission of accurate time signals, space communication systems. Usually sounding of the ionosphere is carried out in the range of 5 ... 30 MHz, at altitudes of up to 1000 km [see, for example, Cosmonautics, Encyclopedia, Moscow: Sov. Encyclopedia, 1985, Ionosphere, Ionosonde, pp. 141-143]. The main requirements for antennas for sensing the ionosphere are range, orientation of the radiation pattern at the zenith, low noise (side lobes).

There is a known meter wave antenna called “Dipole Nadenenko” [see A.L. Drabkin, V.L. Zuzenko. Antenna feeder devices. Textbook. Owls Radio, 1964, pp. 343-345] - analogue. The analogue antenna is a symmetric vibrator of wires located along the generators of a round cylinder, with a diameter of 1 ... 1.5 m, with the number of wires from 6 to 8, the middle sections of which are adjacent to the feeder and its ends have a conical shape, which provides wave resistance 250 ... 400, which allows you to connect the antenna directly to the feeder without matching transformers, with a range of λ _max / λ _min ≈ 2.

The disadvantages of the analogue are:

- low gain;

- insufficient range;

- a large level of side lobes.

The closest analogue is the “Rhombic antenna” [A.L. Drabkin, V.L. Zuzenko. Antenna feeder devices. Textbook. M .: Sov. Radio, 1961, pp. 366-370]. The rhombic antenna is a system of four horizontal wires in the form of a rhombus suspended on the support masts, the length of each wire is 50-150 m, the height of the suspension is 15 ... 30 m, on the one hand the antenna is connected to the feeder of the transceiver, on the other hand, the antenna closes to resistance, equal to the wave impedance of the line formed by the antenna wires, of the order of 600-800 Ohms depending on the distance between the wires, with a radiation pattern along the large diagonal of the rhombus.

The disadvantages of the closest analogue should be considered:

- the presence in the diagram of significant side lobes;

- a small elevation angle of the main lobe of the radiation pattern above the Earth's surface;

- low gain antenna, about 100-150.

The problem solved by the claimed technical solution is to implement a wide-band antenna operating in the entire range of ionospheric sounding frequencies, with a zenith radiation pattern orientation, high gain, low noise, and long life using composite materials.

The technical result is achieved by the fact that the antenna for sensing the ionosphere is made in the form of two rhombuses crossed in orthogonal planes with edge lengths of 58 m of one and 26 m of the second rhombus, suspended on a support mast of composite material 32 m high, creating the geometry of the main diagonal of rhombuses, and two pairs of auxiliary masts with a height of 9 m for suspension of the second corners of rhombuses, brace extensions of the mechanical fastening of masts made of polymer material and conductors of current-carrying wires of rhombuses located along the cylinder generators as ve antenna emitters loaded with a common impedance, matched for the traveling wave mode in the emitters, connected to a multipath earthing switch made in parallel for the mirror counterbalance mode.

The invention is illustrated by drawings, where

figure 1 - structural diagram of the antenna: a) a top view of two crossed rhombs, b) a view of a rhombus with a support mast in one of the orthogonal planes;

figure 2 - calculated radiation patterns: a) a smaller diamond, b) a large diamond, c) the resulting radiation pattern of the antenna;

figure 3 - current paths in a multipath grounding-counterbalance;

4 is a composite elbow of the mast of the suspension of rhombs made of composite material;

5 is a screw pile element of a multipath earthing.

The antenna (Fig. 1 a, b) contains a support mast 1, which creates the geometry of the main diagonal of the suspension of rhombuses 2, 3, current-carrying wires-emitters of the antenna 4, 5, 6, 7, located along the generatrices of the cylinders with central cores 8, 9, 10, 11 made of composite material, bearing the mechanical load of the tension of current-carrying wires, two pairs of auxiliary masts 12, 13, 14, 15 for suspending the second corners of rhombuses, stretching mechanical fastening of the masts 16, load resistance of the emitters 17, mounted on the support mast 1, gas-discharge lightning antenna 18 included about parallel to the load resistance, the ground electrode 19, made according to the multipath scheme on screw pile pipes, buried in the ground 20 and the feeder power emitters 21.

The dynamics of the interaction of the antenna elements is as follows. For sounding the ionosphere in the entire range, it is necessary to provide a ratio of λ _max / λ _{min of the} order of six. A constructive solution was chosen for the antenna emitter in the form of two rhombuses crossed in orthogonal planes, suspended on a high support mast made of durable composite material, creating the geometry of the main diagonal of both rhombuses. This ensures the orientation of the resulting antenna pattern along the main axis, i.e. at the zenith. The range of the antenna is achieved by different sizes of diamonds. For radiation at long wavelengths, a rhombus with a radiator rib length of 58 m, with a total length of 116 m, was used, which ensures the traveling wave mode. For the other edge of the range, with shorter waves (of the order of 10 m), the traveling wave mode is implemented with smaller sizes of the rhombus edges equal to 32 m and 26 m. The radiation patterns of the emitters (each rhombus) can be calculated by the formula [see nearest analogue, p. 368]:

where 1 is the length of the side of the rhombus, φ ₀ is the angle between the edge of the rhombus and the main diagonal, φ is the current angle of the radiation pattern, counted from the axis. Given that the radiation pattern of a rhombic antenna has axial symmetry, the resulting calculated radiation pattern is found as the product of the radiation patterns of orthogonal rhombuses [see analogue, p.122]:

F _rez. = F ₁ (φ, θ) × F ₂ (φ, θ)

The calculated radiation patterns of the rhombuses F ₁ (φ, θ), F ₂ (φ, θ) and the resulting radiation pattern are illustrated in Fig. 3 (a, b, c). There is a relationship between the directional coefficient of the antenna and the solution angles of the radiation pattern at half power [see analogue, p. 124]:

From the graphs of figure 2, the width of the radiation patterns of the emitter of the large rhombus is F ₁ (φ) = 20 °, the smaller rhombus F ₂ (φ) = 36 °, the resulting radiation pattern P _res (φ) = 12 °. The estimated directional coefficient of the claimed device is D≈2300, which is an order of magnitude greater than its value in the closest analogue. Conductivity of the soil at the antenna location has a significant effect on the directivity of antennas of meter waves. The level of the side lobes and the radio brightness temperature of the antenna decrease proportionally (1-R ² ), where R is the reflection coefficient of electromagnetic waves from the earth's surface. For a perfectly reflective surface, R → 1. The latter is achieved by using a beam grounding circuit that extends beyond the projection of the antenna emitters to the ground. The beam circuit of the ground electrode and the current paths in the ground electrode are illustrated in the figure of FIG. 3. All elements of the antenna are made on the existing technical basis. The durability of the antenna is ensured by the use of composite materials in structural elements, stretch marks and diamond pendants. The copositive polymer material of the supporting masts is the serial production of the ApATek scientific-production enterprise [see, Internet, http://www.apatch.ru, structural profiles, metal composite plates]. A composite elbow made of composite material is illustrated in FIG. The multi-beam ground electrode system is made on screw pile elements SVS-57/1650 [see Internet, website http://www.fundex.su/tehnologiya-vintovyh-sv] A screw pile element is a metal pipe with a specially configured blade welded on one side (Fig. 5). On the opposite side of the pipe, a head is welded to connect the antenna ground wire. Screw piles can be quickly screwed into the soil and twisted out of it.

The effectiveness of the antenna is characterized by a significant range, a high coefficient of directional action, a low level of side lobes due to the mirror counterbalance of the multipath earthing switch.

Claims (1)

The antenna for probing the ionosphere is made in the form of two rhombuses crossed in orthogonal planes with edge lengths of 58 m of one and 26 m of the second rhombus, suspended on a support mast of composite material 32 m high, creating the geometry of the main diagonal of rhombs, and two pairs of auxiliary masts 9 m high for suspending the second corners of rhombuses, brace extensions of mechanical fastening of masts made of polymer material and conductors of rhombus current-carrying wires located along cylinder generators as antenna radiators, loaded on a common e resistance, consistent for the mode of traveling waves in the emitters, connected to a multipath earthing switch, made in parallel, for the mode of mirror counterweight.

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