Miniaturized broadband bidirectional antenna for mining

Abstract

The invention relates to the technical field of antennas, in particular to a mining miniaturized broadband bidirectional antenna, which comprises a dielectric substrate, a first metal layer and a second metal layer, and is characterized in that the first metal layer and the second metal layer are respectively arranged on two opposite surfaces of the dielectric substrate; the first metal layer comprises four microstrip balun structures and a T-shaped power division network, and the four microstrip balun structures are connected through the T-shaped power division network; the second metal layer comprises four radiation branches and a metal ground layer, and the four radiation branches are connected through the metal ground layer; each microstrip balun structure is in one-to-one correspondence with the radiation branch knot, each microstrip balun structure is arranged opposite to the corresponding radiation branch knot, and the power division network is arranged opposite to the metal ground layer. The mining miniaturized broadband bidirectional antenna is compact in antenna structure, small in array element spacing, large in impedance and radiation bandwidth, good in radiation stability, simple to process and manufacture and low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of antennas, and in particular to a miniaturized broadband bidirectional antenna for mining. Background Art

[0002] Affected by the special environment of coal mines, the underground multipath fluctuations are serious, the wireless signal attenuation is large, and the coverage range is small, making it difficult to successfully transplant mature wireless communication systems underground. In actual applications, in order to ensure the stable operation of various wireless communication systems underground, the main method is to increase the density of base stations, resulting in high installation and maintenance costs. Antennas, as a device for transmitting / receiving electromagnetic waves, are also a basic component of wireless communication systems. Through the reasonable design and modification of antennas, the above problems can be improved from the source.

[0003] The underground tunnels of coal mines are narrow and long, and are restricted on all sides. When the wireless communication frequency is in the (Ultra High Frequency, UHF) band and above, the propagation characteristics of electromagnetic waves are significantly affected by the tunnel walls. Therefore, the technical parameter requirements for mine antennas are different from those for general ground applications. In view of the narrow and long cross-section of coal mine tunnel structures, mine antennas should have the characteristics of high gain and bidirectional radiation. Bidirectional antennas can effectively increase signal coverage, improve antenna coupling efficiency, and weaken the multipath effect caused by reflections from the side walls of the tunnels by guiding the antenna beam to radiate along both ends of the radial direction.

[0004] Currently, the means to implement bidirectional antennas mainly include:

[0005] 1) Placing two directional antennas back to back has the advantage of a simple layout, but its disadvantage is that the overall structure of the antenna is large, the complexity of device installation is increased, and usually a feed network is required for switching to achieve feeding of the two directional antennas;

[0006] 2) A specially constructed single antenna with bidirectional radiation characteristics, including an ultra-wideband equiangular helical antenna with bidirectional radiation, which stimulates the slot magnetic flux radiation pattern through the slotted metal floor to produce a bidirectional beam. The antenna has a large profile, low gain and narrow bandwidth;

[0007] 3) Forming end-fire / side-fire bidirectional beams by arranging several antennas. Specific methods include arranging several dipole arrays with half-wavelength unit spacing and in-phase excitation, Bruce arrays with in-phase magnetic current excitation, and cascaded ring antenna combinations. However, the antenna array size is large, and because the array element spacing is related to the working wavelength, the bidirectional radiation of the antenna can only be achieved within a limited bandwidth.

[0008] The application environment of coal mines is special, and there are special requirements for the scale, size, and material of array antennas. The general bidirectional array antenna principles and technologies cannot be directly applied to underground wireless equipment. In addition, the current coal mine underground equipment involves many frequency bands, and the existing bidirectional beam antenna is only effective for a single narrow band, which lacks versatility in actual use. Summary of the invention

[0009] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0010] To this end, the present invention provides a miniaturized broadband bidirectional antenna for mining, which has a compact antenna structure, small array element spacing, large impedance and radiation bandwidth, good radiation stability, simple processing and manufacturing, and low cost.

[0011] The miniaturized broadband bidirectional antenna for mining according to an embodiment of the present invention comprises: a dielectric substrate, a first metal layer and a second metal layer, wherein the first metal layer and the second metal layer are respectively arranged on two opposite surfaces of the dielectric substrate;

[0012] The first metal layer includes four microstrip balun structures and a T-type power division network, and the four microstrip balun structures are connected through the T-type power division network;

[0013] The second metal layer includes four radiation branches and a metal stratum, and the four radiation branches are connected by the metal stratum;

[0014] Each of the microstrip balun structures corresponds to the radiation branch node one by one, and each of the microstrip balun structures is arranged opposite to the corresponding radiation branch node, and the power division network is arranged opposite to the metal stratum.

[0015] The beneficial effect of the present invention is that the miniaturized broadband bidirectional antenna for mining of the present invention has a smaller array element spacing and better stability than the existing bidirectional beam array. It has the advantages of wide frequency domain coverage, stable radiation frequency response, high antenna unit integration, compact overall structure and low processing and manufacturing cost, and can be effectively used in the mine tunnel environment, and has broad application prospects.

[0016] According to one embodiment of the present invention, the four microstrip balun structures are respectively a first microstrip balun structure, a second microstrip balun structure, a third microstrip balun structure and a fourth microstrip balun structure;

[0017] The first microstrip balun structure and the second microstrip balun structure are connected in a 180° rotational symmetric manner, and a first connection point A is formed after the connection;

[0018] The third microstrip balun structure and the fourth microstrip balun structure are connected in a 180° rotational symmetric manner, and a second connection point B is formed after the connection;

[0019] A rectangular coordinate system is established with the center point of the dielectric substrate as the origin, wherein the first microstrip balun structure and the third microstrip balun structure are symmetrical about the Y axis, and the second microstrip balun structure and the fourth microstrip balun structure are symmetrical about the Y axis;

[0020] The first connection portion is connected to the second connection portion through the T-type power division network.

[0021] According to one embodiment of the present invention, four radiation branches are distributed in a rectangular array and connected to the metal stratum.

[0022] According to an embodiment of the present invention, each of the radiation branches is a T-shaped structure.

[0023] According to an embodiment of the present invention, each of the radiation branches is provided with a slit groove.

[0024] According to one embodiment of the present invention, each of the microstrip balun structures includes a first vertical microstrip line, a first transverse microstrip line, a bending portion, a second vertical microstrip line, a second transverse microstrip line, and a connecting portion;

[0025] The first vertical microstrip line is perpendicular to the first transverse microstrip line and is connected to one end of the first transverse microstrip line, the other end of the first transverse microstrip line is connected to one end of the bent portion, the other end of the bent portion is connected to one end of the second vertical microstrip line, the second vertical microstrip line is perpendicular to the second transverse microstrip line, the other end of the second vertical microstrip line is connected to one end of the second transverse microstrip line, the second transverse microstrip line is perpendicular to the connecting portion, and the other end of the second transverse microstrip line is connected to the connecting portion.

[0026] According to one embodiment of the present invention, the T-type power division network includes a first horizontal microstrip line, a second horizontal microstrip line, a third horizontal microstrip line, a fourth horizontal microstrip line and a feed port connected in sequence;

[0027] A feeding port is provided at a center point where the second horizontal microstrip line and the third horizontal microstrip line are connected.

[0028] According to an embodiment of the present invention, the width of the first horizontal microstrip line and the fourth horizontal microstrip line is W1, the width of the second horizontal microstrip line and the third horizontal microstrip line is W2, and W1 is greater than W2.

[0029] According to an embodiment of the present invention, the dielectric substrate is a PCB board.

[0030] According to an embodiment of the present invention, the size of the dielectric substrate is 86 mm×41 mm×1 mm, the relative dielectric constant of the dielectric substrate is 4.3, and the loss tangent is 0.02.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0035] Figure 2 It is a schematic structural diagram of the second metal layer of the present invention.

[0036] Figure 3 It is a schematic structural diagram of the first metal layer of the present invention.

[0037] Figure 4 It is a schematic diagram of the surface current distribution of the radiation branch at various frequencies of the present invention.

[0038] Figure 5 It is a schematic diagram of the antenna reflection coefficient result of the present invention.

[0039] Figure 6 It is a 2-D directional schematic diagram of the E-plane (xoy) and H-plane (yoz) of the antenna of the present invention.

[0040] Figure 7 It is a schematic diagram of the 3-D far-field radiation direction of the antenna of the present invention at various frequencies.

[0041] In the figure: 1, dielectric substrate; 2, first metal layer; 3, second metal layer; 21, microstrip balun structure; 22, T-type power division network; 31, radiation branch; 32, metal ground layer; 211, first vertical microstrip line; 212, first transverse microstrip line; 213, bending portion; 214, second vertical microstrip line; 215, second transverse microstrip line; 216, connecting portion; 221, first horizontal microstrip line; 222, second horizontal microstrip line; 223, third horizontal microstrip line; 224, fourth horizontal microstrip line; 225, feeding port. DETAILED DESCRIPTION

[0042] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The present application embodiment provides a miniaturized broadband bidirectional antenna for mining, such as Figure 1-3 As shown, it includes: a dielectric substrate 1, a first metal layer 2 and a second metal layer 3, and the first metal layer 2 and the second metal layer 3 are respectively arranged on two opposite surfaces of the dielectric substrate 1; the first metal layer 2 includes four microstrip balun structures 21 and a T-type power division network 22, and the four microstrip balun structures 21 are connected through the T-type power division network 22; the second metal layer 3 includes four radiation branches 31 and a metal layer 32, and the four radiation branches 31 are connected through the metal layer 32; each microstrip balun structure 21 corresponds to the radiation branch 31 one by one, and each microstrip balun structure 21 is arranged relative to the corresponding radiation branch 31, and the power division network is arranged relative to the metal layer 32.

[0046] In the embodiment, the four microstrip balun structures 21 are respectively a first microstrip balun structure, a second microstrip balun structure, a third microstrip balun structure and a fourth microstrip balun structure; the first microstrip balun structure and the second microstrip balun structure are connected in a 180° rotational symmetric manner to form a first connection point A after being connected; the third microstrip balun structure and the fourth microstrip balun structure are connected in a 180° rotational symmetric manner to form a second connection point B after being connected; in other words, the first microstrip balun structure is 180° rotationally symmetric relative to the first connection point A, and the second microstrip balun structure is 180° rotationally symmetric relative to the second connection point B; a rectangular coordinate system is established with the center point of the dielectric substrate 1 as the origin, the first microstrip balun structure and the third microstrip balun structure are symmetric about the Y axis, and the second microstrip balun structure and the fourth microstrip balun structure are symmetric about the Y axis; the first connection point A is connected to the second connection point B through a T-type power division network 22.

[0047] In an embodiment, four radiating branches 31 are distributed in a rectangular array and connected to the metal layer 32. Furthermore, the four radiating branches 31 are respectively a first radiating branch, a second radiating branch, a third radiating branch and a fourth radiating branch; the first radiating branch and the third radiating branch are symmetrically connected to the metal layer 32 about the Y axis, the second radiating branch and the fourth radiating branch are symmetrically connected to the metal layer 32 about the Y axis, the first radiating branch and the second radiating branch are symmetrically connected to the X axis, and the third radiating branch and the fourth radiating branch are symmetrically connected to the X axis.

[0048] In the embodiment, each radiation branch 31 is a T-shaped structure. A slot 311 is formed on each radiation branch 31 .

[0049] In the embodiment, each microstrip balun structure 21 includes a first vertical microstrip line 211, a first transverse microstrip line 212, a bend 213, a second vertical microstrip line 214, a second transverse microstrip line 215 and a connecting portion 216; the first vertical microstrip line 211 is perpendicular to the first transverse microstrip line 212 and is connected to one end of the first transverse microstrip line 212, the other end of the first transverse microstrip line 212 is connected to one end of the bend 213, the other end of the bend 213 is connected to one end of the second vertical microstrip line 214, the second vertical microstrip line 214 is perpendicular to the second transverse microstrip line 215, the other end of the second vertical microstrip line 214 is connected to one end of the second transverse microstrip line 215, the second transverse microstrip line 215 is perpendicular to the connecting portion 216, and the other end of the second transverse microstrip line 215 is connected to the connecting portion 216.

[0050] In the embodiment, the T-type power division network 22 includes a first horizontal microstrip line 221, a second horizontal microstrip line 222, a third horizontal microstrip line 223, a fourth horizontal microstrip line 224 and a feed port 225 connected in sequence; the feed port 225 is provided at the center point where the second horizontal microstrip line 222 and the third horizontal microstrip line 223 are connected. Furthermore, the width of the first horizontal microstrip line 221 and the fourth horizontal microstrip line 224 is W1, and the width of the second horizontal microstrip line 222 and the third horizontal microstrip line 223 is W2, and W1 is greater than W2, so as to achieve impedance matching.

[0051] In the embodiment, the dielectric substrate 1 is a PCB board, the PCB board material is FR-4, the dielectric substrate 1 has a size of L1*L2*h, that is, 86mm×41mm×1mm in a specific embodiment, the dielectric substrate 1 has a relative dielectric constant of 4.3, and a loss tangent of 0.02.

[0052] In the embodiment, the width of the radiating branch is L3, the spacing between the upper and lower radiating branches is L5, and the spacing between the left and right radiating branches is L4. Further, L3=35mm, L4=15mm, and L5=28mm.

[0053] The antenna is fed via a feed source with a characteristic impedance of 50Ω. The specific working principle is as follows: after energy is fed from the feed port 225, it flows to the first connection point A and the second connection point B with equal amplitude and phase through the first horizontal microstrip line 221, the second horizontal microstrip line 222, the third horizontal microstrip line 223 and the fourth horizontal microstrip line 224 of the power division network, and then fed to the corresponding radiation branch 31 through the feeding balun structure. Since the first feeding balun structure and the second feeding balun structure are rotationally symmetrical with respect to the first connection point A, and the third feeding balun structure and the fourth feeding balun structure are rotationally symmetrical with respect to the second connection point, the current flowing to the slots on the radiation branch 31 has the characteristics of equal amplitude and opposite phase. Figure 4 The surface current distribution diagram of the antenna radiation branch 31 at each frequency point is shown. In the wide frequency domain, the surface currents of the four radiation branches 31 maintain the equal amplitude and reverse characteristics between each other, that is, I 11 =I 12 =-I 21 =-I 22 , at this time, the energy of the first radiation branch and the third radiation branch in the -y axis direction radiation half area and the energy of the second radiation branch and the fourth radiation branch in the +y axis direction radiation half area of ​​the radiation branch 31 cancel each other out, thereby realizing the bidirectional beam radiation characteristics of the antenna in the ±y axis directions. In this state, the size of the spacing L5 between the upper and lower radiation branches is not related to the bidirectional radiation characteristics. Therefore, by compressing the spacing between the upper and lower radiation branches, while ensuring the bidirectional radiation characteristics of the antenna, the overall structure size is greatly reduced, making the overall structure of the antenna small.

[0054] Depend on Figure 5 It can be seen that the -10dB impedance bandwidth of the antenna is 2.8~4.2GHz, and the relative bandwidth is 40%, which can effectively cover the mining 5G n77 (3.3~4.2GHz) frequency band and the commonly used spectrum of the current mining UWB precise positioning system (3.7~4.2GHz). Due to the wide impedance bandwidth and radiation bandwidth, it meets the requirements of wide frequency domain coverage.

[0055] Figure 6 The 2-D radiation pattern of the antenna in the E plane (xoy) and H plane (yoz) at each frequency point is shown. Figure 6 It can be seen that the antenna at each frequency point can realize bidirectional radiation in the ±y-axis ±90° direction, and has the characteristics of beam symmetry and stable frequency response.

[0056] Figure 7 The 3-D far-field radiation pattern of the antenna at each frequency point is shown. Figure 7 It can be seen that the antenna has obvious bidirectional radiation effect and small gain fluctuation in the working frequency range of 3GHz-4.2GHz, showing good radiation-frequency stability.

[0057] When manufacturing the miniaturized broadband bidirectional antenna for mining in this embodiment, it is only necessary to coat copper on both sides of the dielectric substrate 1 through a PCB processing process to form a first metal layer 2 and a second metal layer 3 respectively. The manufacturing method is simple and the manufacturing cost is low.

[0058] In summary, the miniaturized broadband bidirectional antenna for mining of the present invention has smaller array element spacing and better stability than the existing bidirectional beam array. It has the advantages of wide frequency domain coverage, stable radiation frequency response, high antenna unit integration, compact overall structure and low processing and manufacturing cost, and can be effectively used in mine tunnel environment, with broad application prospects.

[0059] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0060] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A miniaturized broadband bidirectional antenna for mining, characterized in that: include: A dielectric substrate (1), a first metal layer (2) and a second metal layer (3), wherein the first metal layer (2) and the second metal layer (3) are respectively arranged on two opposite surfaces of the dielectric substrate (1); The first metal layer (2) comprises four microstrip balun structures (21) and a T-type power division network (22), and the four microstrip balun structures (21) are connected via the T-type power division network (22); The second metal layer (3) comprises four radiation branches (31) and a metal stratum (32), and the four radiation branches (31) are connected via the metal stratum (32); Each of the microstrip balun structures (21) corresponds to the radiation branch node (31) one by one, and each of the microstrip balun structures (21) is arranged relative to the corresponding radiation branch node (31), and the power division network is arranged relative to the metal layer (32).

2. The miniaturized broadband bidirectional antenna for mining as claimed in claim 1, characterized in that: The four microstrip balun structures (21) are respectively a first microstrip balun structure, a second microstrip balun structure, a third microstrip balun structure and a fourth microstrip balun structure; The first microstrip balun structure and the second microstrip balun structure are connected in a 180° rotational symmetric manner, and a first connection point A is formed after the connection; The third microstrip balun structure and the fourth microstrip balun structure are connected in a 180° rotational symmetric manner, and a second connection point B is formed after the connection; A rectangular coordinate system is established with the center point of the dielectric substrate (1) as the origin, the first microstrip balun structure and the third microstrip balun structure are symmetrical about the Y axis, and the second microstrip balun structure and the fourth microstrip balun structure are symmetrical about the Y axis; The first connection point A is connected to the second connection point B via the T-type power division network (22).

3. The miniaturized broadband bidirectional antenna for mining as claimed in claim 1, characterized in that: Four radiation branches (31) are distributed in a rectangular array and connected to the metal layer (32).

4. The miniaturized broadband bidirectional antenna for mining as claimed in claim 1, characterized in that: Each of the radiation branches (31) is a T-shaped structure.

5. The miniaturized broadband bidirectional antenna for mining as claimed in claim 4, characterized in that: Each of the radiation branches (31) is provided with a slit groove (311).

6. The miniaturized broadband bidirectional antenna for mining as claimed in any one of claims 1 to 5, characterized in that: Each of the microstrip balun structures (21) comprises a first vertical microstrip line (211), a first transverse microstrip line (212), a bending portion (213), a second vertical microstrip line (214), a second transverse microstrip line (215), and a connecting portion (216); The first vertical microstrip line (211) is perpendicular to the first transverse microstrip line (212) and is connected to one end of the first transverse microstrip line (212); the other end of the first transverse microstrip line (212) is connected to one end of the bent portion (213); the other end of the bent portion (213) is connected to one end of the second vertical microstrip line (214); the second vertical microstrip line (214) is perpendicular to the second transverse microstrip line (215); the other end of the second vertical microstrip line (214) is connected to one end of the second transverse microstrip line (215); the second transverse microstrip line (215) is perpendicular to the connecting portion (216); the other end of the second transverse microstrip line (215) is connected to the connecting portion (216).

7. The miniaturized broadband bidirectional antenna for mining as claimed in claim 1, characterized in that: The T-type power division network (22) comprises a first horizontal microstrip line (221), a second horizontal microstrip line (222), a third horizontal microstrip line (223), a fourth horizontal microstrip line (224) and a feeding port (225) which are connected in sequence; A feeding port (225) is provided at the center point where the second horizontal microstrip line (222) and the third horizontal microstrip line (223) are connected.

8. The miniaturized broadband bidirectional antenna for mining as claimed in claim 7, characterized in that: The width dimension of the first horizontal microstrip line (221) and the fourth horizontal microstrip line (224) is W1, the width dimension of the second horizontal microstrip line (222) and the third horizontal microstrip line (223) is W2, and W1 is greater than W2.

9. The miniaturized broadband bidirectional antenna for mining as claimed in claim 1, characterized in that: The dielectric substrate (1) is a PCB board.

10. The miniaturized broadband bidirectional antenna for mining as claimed in claim 9, characterized in that: The dimensions of the dielectric substrate (1) are 86 mm×41 mm×1 mm, the relative dielectric constant of the dielectric substrate (1) is 4.3, and the loss tangent is 0.02.

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