RU2601280C1 - Transmitting tunnel antenna - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and specifically to antenna engineering. Proposed transmitting tunnel antenna (TTA) relates to underground antennae (UA) and can be used as a transmitting low-frequency (LF) antenna located in a tunnel drilled in a semi-conducting soil (SCS). TTA consists of a symmetrical vibrator (SV), arms of which of length L are made of K conductors 1 arranged regularly along generatrix cylindrical surface 2 axially symmetric to the inner surface of tunnel 3. In sections of tunnel 3 with interval l_s along the generatrix surface of tunnel 3 into SCS 7 immersed are by N metal rods (MR) 8 of the anchor support. Conductors 1 of the SV arms are secured to the tunnel surface with the help of suspensions 9 providing galvanic coupling of conductors 1 with MR 8 of the anchor support. Invention covers optimum ratios the TTA structure elements providing higher antenna gain and its stability under effects of impact and vibration loads.

EFFECT: technical result of using the TTA is increasing the gain and stability when the TTA is under destabilizing effects.

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Description

The invention relates to the field of radio engineering, namely to antenna technology, and, in particular, the claimed transmitting tunnel antenna (PTA) belongs to the class of underground antennas (PA) and can be used as a transmitting low-frequency (LF) antenna installed in a drilled tunnel in a semiconducting soil characterized by macroscopic parameters: ε _r is the relative dielectric constant and σ is the electrical conductivity.

A known underground antenna (PA) according to US patent No. 3346864, which consists of a set of parallel symmetrical vibrators (CB), the shoulders of each of which are installed in horizontal tunnels drilled in semiconducting soil (BCP). CB connected to the output of the radio transmitter (RRDR), located in the hopper, also buried in the BCP.

A disadvantage of the known PA is its low gain (KU), which is due to the high concentration of the coherent reactive field of SW, leading to significant heat losses in the BCP.

PA is also known according to RF patent No. 215198, 1998, consisting of two tiers spaced along the height of the NE, the shoulders of which are installed in horizontal tunnels drilled in the BCP and connected to the output of the RRDR located in the bunker, also buried in the BCP. The hopper is surrounded by a metal screen.

The disadvantage of this PA is the relatively small KU, which is due to the high concentration of the uncompensated reactive field of the SW, leading to heat losses in the surrounding SW of the BCP.

The closest analogue (prototype) in its technical essence to the claimed PTA is an underground antenna according to the patent of the Russian Federation No. 2262164, publ. 10.10.205, IPC H0Q 1/04. PA - prototype consists of two layers of NE, the shoulders of which in the form of a set of conductors are installed in tunnels drilled in semiconducting soil with macroscopic parameters ε _r and σ.

The SV shoulders are connected to the outputs of the power dividers, which in turn are connected to the output of the RPRD, located in a hopper surrounded by a metal screen. The shoulders of the NE of the first and second tiers are orthogonal, which ensures the formation of an azimuthal plane close to a uniform radiation pattern (MD).

The disadvantages of the prototype are:

high probability of structural damage due to the possible collapse of the arches of the tunnel when exposed to destabilizing factors (vibration or shock loads);

relatively low efficiency (gain) due to the high concentration of the bound reactive field of SW, leading to significant heat losses in the BCP.

The aim of the invention is the development of PTA, ensuring the achievement of higher KU by reducing the concentration of the connected reactive field, while increasing the stability of the antenna structure when exposed to destabilizing factors, such as shock and vibration loads.

The specified technical result is achieved by the fact that in a known transmitting tunnel antenna containing a symmetric vibrator (CB), shoulders of which length L are placed in a cavity of a tunnel with a cross-section diameter D _t drilled in a semiconducting soil with a relative dielectric constant ε _r and electrical conductivity σ, the ends of the CB shoulders adjacent to each other are connected to the output of the RPRD installed in the hopper, surrounded by a metal screen and placed in the BCP, along the generatrix of the tunnel surface with an interval of l _s evenly in BCPs are immersed along N rods of anchor support. The rods of length l _{st are} oriented in the direction from the center of the cross section of the tunnel into the interior of the BCP. Each shoulder CB is made in the form of a set of K conductors located uniformly along the generatrix of the cylindrical surface with a cross-section diameter D _in less than D _t . A cylindrical surface with a cross-sectional diameter D _{in is} axisymmetric with the inner surface of the tunnel. The conductors of the SV arms are mechanically bonded to the surface of the tunnel and conductively connected to the rods of the anchor lining.

, где λ_max - максимальная длина волны рабочего диапазона ПТА; $${\epsilon }_r^{\text{'}}={\epsilon }_r+j60\sigma {\lambda }_{\max }$$

- относительная комплексная диэлектрическая проницаемость грунта.The length L of each shoulder CB is selected from the condition L≥0.1 $${\lambda }_{\max }/\sqrt{\left|{\epsilon }_r\text{'}\text{'}\right|}$$

where λ _max is the maximum wavelength of the operating range of the PTA; $${\epsilon }_r^{\text{'}\text{'}}={\epsilon }_r+j60\sigma {\lambda }_{\max }$$

- the relative complex permittivity of the soil.

The length l _{st of the} anchor support rods is selected within the range of l _st = (0.5-1.0) D _t , and the number N of anchor support rods in each section is selected within the range of N = 8-12. The number K of conductors 1 forming each arm of the CB is selected within K = 4-8.

The intervals l _c between the sections of the tunnel in which the metal rods are installed are selected in the range l _c = (1,0-1,5) D _m .

Thanks to this new set of essential features, the PTA provides reinforcement of the tunnel arch and reduces the likelihood of its collapse due to the possible occurrence of fracturing under the influence of shock or vibration loads. At the same time, the use of rods increases the equivalent diameter of the SV arms and, therefore, reduces its wave impedance, which leads to a decrease in the concentration of a connected reactive field and a decrease in heat losses in a semiconducting soil. The aforementioned indicates an increase in the effectiveness (CI) of PTA, i.e. the possibility of achieving a technical result when using the claimed antenna.

The claimed device is illustrated by drawings, which show:

in FIG. 1 - general view of the PTA (longitudinal section);

in FIG. 2 - view of the PTA (cross section);

in FIG. 3 is a drawing explaining the flow of high-frequency currents along the elements of the PTA;

in FIG. 4 is a drawing explaining the operation of the PTA;

in FIG. 5 - the results of comparative measurements of the antenna gain.

The claimed PTA shown in FIG. 1, consists of a symmetric vibrator, the shoulders of which are of length L made of K conductors 1 located uniformly along the generatrix of the cylindrical surface 2 with a cross-section diameter D _c . The cylindrical surface 2 formed by the conductors 1 is located axisymmetrically with the inner surface of the tunnel 3. The ends of the conductors 1 of the CB arms adjacent to each other are connected to the output of the RPRD 4 installed in the hopper 5 and surrounded by a metal screen 6. The connection of the shoulders of the CB to RRDR 4 can be performed in various ways:

connecting the SV arms to the balanced output of the RPRD 4 (Fig. 1a);

according to the scheme using two homogeneous RRDRs, each of which is connected between the central ground electrode 10, the role of which is played by the metal screen 6 of the hopper 5, and the corresponding CB arm (see Fig. 1b).

In sections of the tunnel 3 with an interval of l _s along the generatrix of the surface of the tunnel 3 in the BCP 7 are immersed uniformly along N metal rods 8 with a length of l _st and a diameter of d _st anchor lining. The rods 8 are oriented from the center of the cross section of the tunnel 3 (point "o") inland BCP 7 (see also Fig. 2). In FIG. 2 shows eight rods 8 mounted in each of the sections. The conductors 1 of the CB arms are bonded to the surface of the tunnel 3 using suspensions 9, for example, in the form of conductors that provide galvanic coupling of the conductors 1 of the CB arms with metal rods 8.

, при этом обеспечивается минимально допустимое снижение эффективности (КУ) ПТА. Длина l_ст и диаметр d_ст стержней 8 анкерной крепи выбирают из условий l_ст=(0,5-1,0)D_т, d_ст=(0,005÷0,02) l_ст. При указанных размерах стержней 8 компромиссно учитываются требования по экономическим затратам на построение ПТА и обеспечению требуемого уровня надежности сохранения целостности туннеля при дестабилизирующих воздействиях.The length L of each of the shoulders CB is selected from the condition L≥0.1 $${\lambda }_{\max }/\sqrt{\left|{\epsilon }_r\text{'}\text{'}\right|}$$

At the same time, the minimum permissible decrease in efficiency (CI) of PTA is provided. The length l _st and the diameter d _st rods 8 of the anchor support are selected from the conditions l _st = (0.5-1.0) D _t , d _st = (0.005 ÷ 0.02) l _st . With the indicated dimensions of the rods 8, the requirements for the economic costs of constructing the PTA and ensuring the required level of reliability of maintaining the integrity of the tunnel under destabilizing effects are compromised.

The diameter D _{t of the} tunnel and its length 2L is chosen taking into account the frequency range of the PTA, its required efficiency and taking into account the peculiarities of mining operations. The ratio of the diameters D _in / D _{t is} chosen taking into account both design considerations and the requirements for the most complete use of the inner space of the tunnel, which is necessary to achieve the maximum possible efficiency of the PTA. Given these requirements, choose D _in / D _t = (0.8-0.95).

The intervals l _s between the sections of the tunnel 3, where metal rods 8 are immersed in the BCP 7, are selected within the limits l _s = (1.0-1.5) D _t .

As a RPRD, you can use any known and commercially available radio transmitter operating in the low frequency range, for example, a radio transmitter of type R-643 or type 15E 1780.

The conductors 1 of the SV arms can be made in various ways, for example, from a cable of the type RK75-44-19B with removed outer insulation. To reduce the shunting action of the end capacitance at the points of connection to the output of the RPRD 4 conductors 1 forming the arms of the CB, they are electrically connected to each other in the form of a cone (see Fig. 1).

Declared PTA works as follows. When RPRD 4 is turned on, a high-frequency (including) conduction current I _pr flows along the arms of the CB, which can be provided in the form of a linear conductor formed by conductors 1 with an equivalent diameter D _ve (see Fig. 3). In addition, the conductivity current of the first arm flows to each of the rods 8 electrically connected to the conductors 1 of the arms of the CB. Further, through bias currents I _cm including the current closes in the form of a conduction current I _pr along the second arm. Such a model can be represented in the form of a distributed circuit, including elements of the linear inductance L ₁ and linear capacitance C ₁ (see Fig. 4).

, где L₁ - значение индуктивности на единицу длины антенны, С₁ - усредненное по длине антенны значение емкости на единицу длины эквивалентного вибратора. Снижение ρ указывает на уменьшение концентрации связанного с антенной реактивного поля и, следовательно, снижение потерь в полупроводящем грунте, окружающем ПТА.The presence of rods 8 increases the distributed capacity of the equivalent vibrator, which leads to a decrease in the wave resistance ρ of the equivalent vibrator (see the book Antennas, part 1, edited by Yu.K. Zhuravtsev. - L .: VKAS, p. 21), t. e $$\rho =\sqrt{L_{\mathrm{one}}/C_{\mathrm{one}}}$$

where L ₁ is the inductance value per unit length of the antenna, C ₁ is the capacitance averaged over the length of the antenna per unit length of the equivalent vibrator. A decrease in ρ indicates a decrease in the concentration of the reactive field associated with the antenna and, consequently, a decrease in losses in the semiconducting soil surrounding the PTA.

Testing the feasibility of achieving the claimed technical result when using PTA was performed during comparative experimental measurements of the effectiveness of the claimed antenna and prototype.

The measurement conditions are as follows:

the maximum wavelength of the working wavelength range λ _max = 3 · 10 ⁴ m; L = 700 m; D _t = 6 m; D _ve = 5 m; l _article = 4.5 m; d _article = 4.5 cm; l _s = 7 m; N = 8; K = 8; soil: ε _r = 10; σ = 5 · 10 ^-5 S / m.

In the course of the experiment, the levels of the radiated field in the far zone of the declared antenna and prototype were measured, followed by an estimation of the QW value in accordance with the known method described in the book: Fradin A.Z., Ryzhkov EV Measuring the parameters of antenna-feeder devices. Ed. 2nd, supplemented, - M .; “Communication”, 1972, p. 262-271.

The results shown in FIG. 5, give grounds for the following conclusions. In the range L / λ = 0.03-0.3, the gain of the claimed antenna in comparison with the prototype is higher from 2 to 3.5 dB. At the same time, the introduction of anchor support rods into the design of the PTA makes the claimed antenna more resistant to shock and vibration loads. The above indicates the possibility of achieving the formulated technical result when using the claimed transmitting tunnel antenna.

Claims (5)

1. Transmitting tunnel antenna (PTA), containing a symmetric vibrator (CB), whose arms of length L are placed axisymmetrically in the cavity of the tunnel with a cross-section diameter D _t drilled in semiconducting soil with a relative dielectric constant ε _r and electrical conductivity σ adjacent to each other to each other, the ends of the CB arms are connected to the output of a radio transmitter (RRDR) installed in a hopper located in a semiconducting soil and surrounded by a metal screen, characterized in that along the generatrix of the tunnel surface at intervals

evenly immersed in soil along N metal rods of anchor support, rods of length

oriented from the center of the cross section of the tunnel depth semiconducting ground, each arm SV is made in the form of a set of K conductors disposed uniformly along the generatrix of the cylindrical surface with the cross-sectional diameter D _to a smaller diameter D _m and axisymmetric with the inner surface of the tunnel, shoulders wires SW are bonded with the surface the tunnel and are galvanically connected to the rods of the anchor lining. 2. The transmitting tunnel antenna according to claim 1, characterized in that the length L of each SV arm is selected from the condition

where λ _max is the maximum wavelength of the working wavelength range,

- the relative complex permittivity of the soil. 3. The transmitting tunnel antenna according to claim 1, characterized in that the length

anchor rods selected within

. 4. The transmitting tunnel antenna according to claim 1, characterized in that the number N of anchor support rods installed in each of the sections of the tunnel is selected within N = 8-12. 5. The transmitting tunnel antenna according to claim 1, characterized in that the intervals

between the sections of the tunnel in which the metal rods are installed, are selected within

.

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