RU2488201C2 - Antenna - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: antenna is matched with mechanical impedance, a communication channel and can be used as a transmitting antenna. The antenna consists of an electric dipole earthed at the ends or a frame antenna on a canvas which forms the frame of the antenna or an electric dipole earthed at the ends successively worn (threaded) in-phase, a plurality of ferrite magnetic antennae consisting of a short-circuited ferrite core which forms with the canvas of the antenna the primary winding of a current transformer and with a radiator, which is made from a linear ferrite core encircled by a common inductance coil which is the secondary winding of the current transformer, whose ends are connected in parallel to a capacitor for resonance tuning to the frequency of the transmitted signal. To obtain a circular pattern of the antenna, the number of linear ferrite cores can be equal to two and they should be placed at an angle of 90 degrees relative each other. Comparison tests of the disclosed antenna using just five ferrite magnetic antennae worn and connected in-phase on the canvas of a known frame antenna with diameter of 115 mm at frequency of 11 kHz yielded a gain of 32 dB.

EFFECT: high efficiency owing to increase in magnetic induction in the communication channel.

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Description

The proposed antenna can be used as a transmitter when organizing wireless communication with an electromagnetic field through an array of rocks in mines.

From [1] it is known that to transmit low-frequency signals through a rock mass, an electric dipole grounded at the ends is used as a transmitting antenna. An electric dipole, a web, is made of an electric wire, usually insulated, of length l _g many times shorter than the wavelength λ of the transmitted signal. Therefore, to ensure the flow of more current, the electric dipole at the ends is grounded. In [1] it is indicated that the efficiency of such an antenna is 1-2%. Since the canvas of an electric dipole has an inductance L, when a current I flows around it, a magnetic flux arises around the canvas [2]

$$f=L\cdot I.\left(\mathrm{one}\right)$$

It is also known from [3] that to increase the current in the dipole, and in fact the magnetic flux, use the parallel connection of several, two electric dipoles, grounded at their ends with their in-phase power supply, excitation.

From [4] it follows that the antenna, which is 20 times shorter than its wavelength, emits only 5-10% of the energy entering it, the rest of the input energy is used to heat the antenna sheet and to heat the soil.

Since the wave impedances of these antennas are not consistent with the wave impedance of the communication channel, their efficiency is small.

In some cases, large-sized loop antennas are used [5], in which, to increase the magnetic flux, the frame is tuned to resonance by sequentially connecting a capacitor antenna [6] to the fabric web to compensate for the inductive resistance at the frequency of the transmitted signal. Since the wave impedance of the known loop antennas is not consistent with the wave impedance of the communication channel, which is a rock mass, their efficiency is also small.

A ferrite magnetic antenna is known [7], in which the wave impedance can be matched with the wave impedance of the medium, the communication channel, however, to use it as transmitting its geometric dimensions and weight, it will be enormous, which will complicate its manufacture and use, since the inductor it is one, common and has the same number of turns; its inductive resistance for a linear ferrite core to inductive resistance to a short-circuited ferrite core is not only not the same, but also smaller, it has m hundred and loss of transmitted power, ie, transmission efficiency. In addition, the above antennas have a limited directivity pattern.

The purpose of the proposed antenna is the simplicity of the transmitting antenna, increasing its efficiency, efficiency by increasing the flux of magnetic induction into the communication channel, both by increasing the inductance of the sheet of an electric dipole, grounded at the ends, or a loop antenna, according to formula (1), and by matching wave impedance of the proposed antenna with wave impedance of a communication channel channel for transmitting maximum signal power to a communication channel

This goal is achieved due to the fact that many ferrite magnetic antennas, consisting of a short-circuited ferrite core, are connected by a common inductor with a linear ferrite rod and a capacitor connected in parallel with a common inductor, are wired (strung) by short-circuited ferrite cores of ferrite magnetic antennas in-phase to an electrical dipole at the ends or onto the canvas of the loop antenna, forming the primary winding of the set of current transformers, this is a set of single ferrite magnetic antennas, consisting of a short-circuited ferrite core and a linear ferrite rod, can be interconnected both by full and partial switching of the secondary coil of the current transformer by an inductor by transformer or autotransformer coupling with a ferrite linear rod parallel to the ends Inductor which capacitor is on.

The electrical circuit of the proposed antenna, such as an electric dipole, grounded at the ends, is shown in figure 1, the loop antenna in figure 2.

Structurally, the antenna is made of an electric dipole, grounded at the ends, or a frame antenna, on the canvas forming the antenna frame or an electric dipole, grounded at the ends, sequentially worn (strung) in-phase many ferrite magnetic antennas consisting of a short-circuited ferrite core forming an antenna with a cloth the primary winding of the current transformer, and a linear ferrite rod, covered by a common inductor, which is the secondary winding of the current transformer, in parallel to the ends of which the capacitor is turned on - Fig.3a, and Fig.3b shows a ferrite magnetic antenna, but with a partial arrangement of the number of turns of the secondary winding of the current transformer on a short-circuited ferrite core and its larger number of turns on a linear ferrite rod, shown in Fig.4, for coordination of their inductive resistances, a capacitor is connected parallel to the ends of the inductor, in some cases the number of linear ferrite rods for ferrite magnetic antennas can be two and they are located relatively each other should be at an angle of 90 degrees, in this case the secondary winding of the current transformer, which is the common inductor of a ferrite magnetic antenna, as for a short-circuited ferrite core and two linear ferrite rods, is partially separated and covers them with its turns, moreover, as in the case for one linear ferrite core, a larger number of turns can be located on two linear ferrite rods, dividing among themselves, figure 5 and figure 6, respectively.

The antenna works as follows.

When electric current flows through a sheet of ground at the ends of an electric dipole or loop antenna around the sheet, a magnetic flux arises, part of which is selected and concentrated in a short-circuited ferrite core in the existing sets of ferrite magnetic antennas. The magnetic flux density in each of the many short-circuited ferrite cores increases by _a factor of µ by _the magnetic permeability of the core compared to air [8, p. 46, 47; 9, p. 74, 83; 10, p. 164, 165, 186]. This magnetic flux concentrated in the core and “amplified” by _a factor of a few times due to a decrease in magnetic resistance compared to air through the secondary winding of a current transformer, which is a common inductor, induces a magnetic flux in them for a linear ferrite rod. That is, the magnetic flux excited by the primary winding of the current transformer of the short-circuited ferrite core induces self-induction emf in the secondary winding, which, in turn, due to the resonance of the current arising in the inductor circuit and the capacitor at the signal frequency induces a magnetic flux scattering in linear ferrite a rod for its radiation into space, a communication channel.

The capacitor serves to compensate for the reactance created by the secondary coil of the current transformer in this circuit at the frequency of the transmitted signal, which, in turn, increases the magnetic flux scattering in the linear ferrite core, and since the magnetic permeability of the short-circuited ferrite core and linear ferrite core can differ, then to transfer the entire magnetic flux induced in the short-circuited ferrite core, transfer it to the linear ferrito as much as possible the first rod is necessary to harmonize their inductances. For example, if the magnetic permeability of the short-circuited ferrite core is greater than the permeability of the linear ferrite rod, then the part of the inductance coil on the linear ferrite rod should be as many times (or less), in Fig. 4, for illustration and explanation, the operation of the ferrite magnetic antenna in Fig. .3b,

$$m=\sqrt{\frac{L_o{\mu }_o}{L\_\mu \_}},\left(2\right)$$

where m is a coefficient determining the difference in the number of turns;

L _o µ _o - the inductance of the coil of its part with respect to the short-circuited ferrite core;

L_µ_ is the inductance of the coil of its part from the permeability of a linear ferrite rod.

This condition allows you to match the wave impedance of a ferrite magnetic antenna with the wave impedance of the communication channel and transmit the maximum power (density) of the magnetic flux to the communication channel.

The total radiation flux of the antenna is determined from the sum of the magnetic fluxes in-phase emitted by each ferrite magnetic antenna individually

$$F_{\sum }=F_{\mathrm{one}}+F_2+...+F_n,\left(3\right)$$

where Ф ₁ , Ф ₂ , ... Ф _n is the magnetic flux of radiation of each individually ferrite magnetic antenna;

n is the serial number of the ferrite magnetic antenna.

In this case, we can write formula (1) in the form

$$F_n={\mu }_o\cdot L_I\cdot I,\left(\mathrm{four}\right)$$

where µ _o is the magnetic permeability of the short-circuited ferrite core;

L _I - inductance of the primary winding of the current transformer, part of the antenna sheet;

I is the current in the antenna.

The use of the ferrite magnetic antennas of FIG. 5 and FIG. 6 by introducing a second linear ferrite rod and placing them at an angle of 90 degrees relative to each other allows you to create, for example, a circular radiation pattern for a loop antenna [11, p. 66, Fig. 3.24] . For this, the secondary winding of the ferrite magnetic antenna of the formed current transformer with the antenna sheet is divided into two, one for one linear ferrite rod, the other for the other. Moreover, to match their inductive resistance, a larger number of turns of the inductor can be located on linear ferrite rods than on a part of a short-circuited ferrite core.

The object of the invention is achieved by increasing the inductance of the sheet of a grounded electric dipole at the ends or of the loop antenna by introducing many short-circuited ferrite cores with high magnetic permeability into the "chain" of the antenna sheet and removing the induced magnetic energy from them in the presented manner and transmitting it in an optimal way to the communication channel, which ensures that the technical solution meets the criterion of novelty, because it is not known from the prior art and is significantly different from all previously known technical solutions to achieve a positive effect in the form of an increase in the magnetic flux on radiation, so necessary on the receiving side of the communication line [11, p. 38], i.e. increases efficiency, communication range, improves S / N, C / P ratios with equal energy costs compared to known antennas, which is the aim of the invention. Therefore, these distinguishing features are significant, and the proposed technical solution meets the criterion of inventive step.

Proof of the effectiveness of the proposed antenna.

7, 8 shows a comparative experiment of the claimed antenna with a known loop antenna. For this purpose, a well-known frame antenna with a diameter of 115 mm was made, consisting of two turns of an insulated wire with a diameter of 0.5 mm, and the claimed antenna of FIG. 2 with a frame diameter of also 115 mm and consisting of two turns of the same wire, were put in phase on the canvas of the frame included five identical ferrite magnetic antennas according to figure 3 (due to the simplicity and speed of their implementation), consisting of a short-circuited ferrite core type K17.5 * 8 * 5 mm grade M3000 NM and a linear ferrite core brand M400 NN with a length of 20 cm, diameter 10 mm and total th inductor, which contained 100 turns of PEL wire with a diameter of 0.25 mm and a capacitor of about 6800 pF for tuning into resonance at a frequency of 10867 Hz (+/- 348 Hz).

A similar (five) ferrite magnetic antenna was used as the receiving antenna. Fig. 7 shows a diagram of an experiment when the transmitting and receiving antennas were located in both cases at the same distance from each other in series, i.e. in length, and in Fig. 8, the transmitting and receiving test antennas were located in parallel.

From the results of the comparative experiment, it can be seen that the gain of the claimed antenna is significant and amounted to 32 dB.

The experiment proved that the proposed antenna has a large emitting positive effect compared to known antennas, therefore, its efficiency is higher, which is the purpose of the invention.

Literature

1. Korchagin Yu.A., Salomatov V.P., Chernov A.A. Radio communication in conductive media. Novosibirsk: Science. Sib. Department, 1990, p. 47, Fig. 3.1.

2. Kuznetsov M.I. Fundamentals of Electrical Engineering. Ed. Dr. tech. Sciences S.V. Strakhova. 9th ed., M., Higher School, 1964, p. 186.

3. Wireless mine communication system with in-phase excited dipoles. Krinitsin L.A., Vyskubenko V.P. Mountain Journal. Izv. higher textbook. Head 1978, No. 1, 74-76 p.

4. Superconducting antenna. Science and life. No. 3, 1989, p. 55.

5. Schwartz B.A. Operational wireless inductive communication within the enterprise (Fundamentals of theory and calculation). - 2nd ed., Revised. and add. M .: Communication, 1978.

6. Grechikhin A.I. Competitions "fox hunting". Ed. DOSAAF. M. 1973 (p. 28, fig. 13).

7. A.S. 1569925 USSR A1, H01Q 7/08.

8. Matveev G.A. and Khomich V.I. Coils with ferrite cores. Ed. 2nd add. M., "Energy", 1967.

9. Stallions I.P. Electric and magnetic circuits: Fundamentals of electrical engineering. - L .: Energoatomizdat. Leningra. Branch, 1982.

10. Barnes J. Electronic construction: Methods to combat interference: Per. from English - M.: Mir, 1990.

11. Kalikhman S.G., Levin Y.M. Fundamentals of the theory and calculation of broadcasting receivers on semiconductor devices. Ed. "Communication", M., 1969.

Claims (2)

1. An antenna consisting of an electric dipole grounded at the ends, connected at the other ends to a signal source, or a loop antenna connected to a signal source, and a ferrite magnetic antenna consisting of a short-circuited ferrite core and one linear ferrite core, covered by a common inductor and a capacitor connected in parallel with an inductor, characterized in that many ferrite magnetic antennas are worn with short-circuited ferrite cores of ferrite magnes antennas in phase on the antenna sheet of an electric dipole, grounded at the ends, or on the canvas of the loop antenna, forming many current transformers with the antenna sheet. 2. The antenna according to claim 1, characterized in that the plurality of ferrite magnetic antennas consist of two linear ferrite rods and ferrite rods are arranged relative to each other at an angle of 90 °, and the inductor, the secondary winding of the current transformer, is divided into two sequential coils, each of which, with its turns, it covers both one linear ferrite core and the other linear ferrite core with a short-circuited ferrite core of a ferrite magnetic antenna.

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