Near-field antenna with strong directivity

Abstract

The utility model relates to a near-field antenna with strong directivity. The near-field antenna comprises a circuit board and a coaxial cable, an oscillator unit and a feed network are formed on the front surface of the circuit board; the oscillator unit is a square with two opposite corners forming chamfers, the length L of each side of the oscillator unit is 80 + / -3mm, the chamfer angle of each chamfer of the oscillator unit is 45 degrees, and the chamfer distance range of each chamfer of the oscillator unit is 13 + / -1mm; the number of the oscillator units is 16, and the 16 oscillator units are distributed to form a rectangular oscillator array with four rows and four columns. In the rectangular oscillator array, the size range of the distance D1 between every two adjacent columns of oscillator units is 58 + / -2mm, and the size range of the distance D2 between every two adjacent rows of oscillator units is 25 + / -2mm; an inner conductor of the coaxial cable feeds each oscillator unit through the feed network, and an outer conductor of the coaxial cable is connected and conducted with the ground. The antenna has the characteristics of simple structure, scientific design, low production cost, small lobe width, strong beam directivity and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of RFID application technology, especially a near field antenna with strong directivity. BACKGROUND

[0002] The near field antenna is a kind of antenna type for wireless communication, and its working principle is based on the transmission of electromagnetic wave.At present, the lobe width of the near field antenna on the market is large when in use, and there is the problem of insufficient directivity.Such near field antenna is prone to misreading when in use, and has poor directivity and reduced gain, so the application effect is not good.Based on the existing problems of the near field antenna in use, it is urgent to design a near field antenna with strong directivity to meet the use requirement of users. CONTENT OF UTILITY MODEL

[0003] The utility model aims at providing a kind of near field antenna with strong directivity, which has the advantages of simple structure, scientific design, low production cost, small lobe width and strong beam directivity.

[0004] The technical scheme of the utility model is realized as follows: a kind of near field antenna with strong directivity, including circuit board and coaxial cable;In particular, the front surface of the circuit board is formed with a vibrator unit and a feed network by a copper-clad method;The vibrator unit is a square with chamfer formed at two opposite corners, the length L of each side of the vibrator unit is 80±3mm, the chamfer angle of each chamfer of the vibrator unit is 45°, and the chamfer distance range of each chamfer of the vibrator unit is 13±1mm;The number of vibrator units is 16, and the 16 vibrator units are distributed to form a rectangular vibrator array of 4 rows and 4 columns;In the rectangular vibrator array: the size range of the spacing D1 between each adjacent 2 column vibrator units is 58±2mm, and the size range of the spacing D2 between each adjacent 2 row vibrator units is 25±2mm;

[0005] The 4 rows of vibrator units of the rectangular vibrator array are respectively referred to as the first vibrator row, the second vibrator row, the third vibrator row and the fourth vibrator row;The first vibrator row, the second vibrator row, the third vibrator row and the fourth vibrator row are arranged along the column array direction of the rectangular vibrator array in turn;

[0006] The feed network includes a first circuit, a second circuit, a third circuit, a fourth circuit, a fifth circuit, a sixth circuit and a seventh circuit;

[0007] The first circuit, the second circuit, the third circuit and the fourth circuit each include 9 first straight line segments, which are A1, A2, A3, A4, A5, A6, A7, A8 and A9 respectively;The length direction of A1, A2, A3, A4 and A5 is along the row array direction of the rectangular vibrator array;

[0008] The line length of A1 ranges from 51±2mm, and the line width of A1 ranges from 3±0.5mm; one end of A1 is connected to one end of A2, and the other end of A1 is connected to one end of A3;

[0009] The line length of each of A2 and A3 ranges from 42±2mm, and the line width of each of A2 and A3 ranges from 5.5±0.5mm; the other end of A2 is connected to one end of A4, and the other end of A3 is connected to one end of A5;

[0010] The line length of each of A4 and A5 ranges from 138±2mm, and the line width of each of A4 and A5 ranges from 3±0.5mm;

[0011] The line length of each of A6, A7, A8 and A9 ranges from 7±0.5mm, and the line width of each of A6, A7, A8 and A9 ranges from 3±0.5mm; A6, A7, A8 and A9 are all on the same side of A1; one end of A6 is perpendicularly connected to one end of A4 which is connected to A2, and one end of A7 is perpendicularly connected to one end of A4 which is away from A2; one end of A8 is perpendicularly connected to one end of A5 which is connected to A3, and one end of A9 is perpendicularly connected to one end of A5 which is away from A3;

[0012] The first circuit is between the first row of oscillators and the second row of oscillators; the four first straight line segments of A6, A7, A8 and A9 of the first circuit correspond to the four oscillator units of the first row of oscillators one by one, and the other end of each of A6, A7, A8 and A9 of the first circuit is perpendicularly connected to the middle position of the side of the corresponding oscillator unit which faces the second row of oscillators;

[0013] The second circuit is between the second row of oscillators and the third row of oscillators; the four first straight line segments of A6, A7, A8 and A9 of the second circuit correspond to the four oscillator units of the second row of oscillators one by one, and the other end of each of A6, A7, A8 and A9 of the second circuit is perpendicularly connected to the middle position of the side of the corresponding oscillator unit which faces the third row of oscillators;

[0014] The third circuit is between the third row of oscillators and the fourth row of oscillators; the four first straight line segments of A6, A7, A8 and A9 of the third circuit correspond to the four oscillator units of the third row of oscillators one by one, and the other end of each of A6, A7, A8 and A9 of the third circuit is perpendicularly connected to the middle position of the side of the corresponding oscillator unit which faces the fourth row of oscillators;

[0015] The fourth circuit is located on one side of the fourth row of vibrators facing away from the third row of vibrators; the four first straight line segments A6, A7, A8 and A9 of the fourth circuit correspond to the four vibrator units of the fourth row of vibrators one by one, and the other ends of A6, A7, A8 and A9 of the fourth circuit are connected in perpendicular to the middle positions of the sides of the vibrator units corresponding thereto facing away from the third row of vibrators;

[0016] The fifth circuit is located between the second circuit and the third circuit, and the fifth circuit includes three second straight line segments, which are B1, B2 and B3 respectively;

[0017] The length directions of B1, B2 and B3 are arranged along the column array direction of the rectangular vibrator array respectively; the line length of B1 ranges from 32±1mm, the line width of B1 ranges from 3.5±0.5mm, one end of B1 is connected in conduction with one end of B2, and the other end of B1 is connected in conduction with one end of B3;

[0018] The line length of B2 and B3 ranges from 35±1mm respectively, and the line width of B2 and B3 ranges from 8±0.5mm respectively; the other end of B2 is connected in perpendicular to the center position of the length direction of A1 of the second circuit; the other end of B3 is connected in perpendicular to the center position of the length direction of A1 of the third circuit;

[0019] The sixth circuit and the seventh circuit each include eight third straight line segments, which are C1, C2, C3, C4, C5, C6, C7 and C8 respectively; C1, C2, C3, C4, C5, C6, C7 and C8 of the sixth circuit and the seventh circuit are connected in conduction in turn, and among the seven third straight line segments C2, C3, C4, C5, C6, C7 and C8, two adjacent third straight line segments are perpendicular to each other;

[0020] The length directions of C1 and C2 are arranged along the column array direction of the rectangular vibrator array; the line length of C1 ranges from 25±1mm, and the line width of C1 ranges from 7±0.5mm; the line length of C2 ranges from 27±1mm, and the line width of C2, C3, C4, C5, C6, C7 and C8 ranges from 3.5±0.5mm respectively;

[0021] The line length of C3 ranges from 20±1mm;

[0022] The line length of C4 ranges from 15±1mm, and C4 is located on the side of C3 facing away from C2;

[0023] The line length of C5 ranges from 40±1mm, and C5 and C3 are both located on the same side of C4;

[0024] The line length of C6 ranges from 15±1mm, and C6 is located on the side of C5 facing away from C4;

[0025] The line length of C7 ranges from 20±1mm, and C7 and C5 are on the same side of C6;

[0026] The line length of C8 ranges from 20±1mm, and C8 is on the side of C7 away from C6;

[0027] The sixth circuit is between the first circuit and the second circuit, the end of C1 of the sixth circuit away from C2 is connected to the center of the length direction of A1 of the second circuit in a vertical manner, and the end of C8 of the sixth circuit away from C7 is connected to the center of the length direction of A1 of the first circuit in a vertical manner;

[0028] The seventh circuit is between the third circuit and the fourth circuit, the end of C1 of the seventh circuit away from C2 is connected to the center of the length direction of A1 of the third circuit in a vertical manner, and the end of C8 of the seventh circuit away from C7 is connected to the center of the length direction of A1 of the fourth circuit in a vertical manner;

[0029] The inner conductor of the coaxial cable is connected to the middle of the length direction of B1 of the fifth circuit in a conductive manner, and the outer conductor of the coaxial cable is connected to the ground in a conductive manner.

[0030] Further, the back surface of the circuit board is formed with a reflecting surface by a copper cladding manner.

[0031] The connection structure of the coaxial cable and the feeder network in the present scheme has two kinds:

[0032] One is that the back surface of the circuit board is further formed with a feeder connection area by a copper cladding manner; the feeder connection area is circular, the diameter φ of the feeder connection area is 2.5±0.1mm, and the feeder connection area is insulated and separated from the reflecting surface; the feeder connection area and the middle of the length direction of B1 of the fifth circuit are connected in a conductive manner through a copper sinking hole formed on the circuit board; the model of the coaxial cable is RG58, the inner conductor of the coaxial cable is connected to the feeder connection area in a conductive manner, the outer conductor of the coaxial cable is connected to the reflecting surface in a conductive manner, and the reflecting surface is connected to the ground in a conductive manner.

[0033] The other is that the front surface of the circuit board is formed with a feeder connection structure by a copper cladding manner; the feeder connection structure includes a first connection end and a second connection end; the first connection end and the second connection end are insulated and separated, and the first connection end is connected to the middle of the length direction of B1 of the fifth circuit in a conductive manner; the second connection end is beside the first connection end, and the second connection end and the reflecting surface are connected in a conductive manner through two copper sinking holes formed on the circuit board; the model of the coaxial cable is RG316, the inner conductor of the coaxial cable is connected to the first connection end in a conductive manner, the outer conductor of the coaxial cable is connected to the second connection end in a conductive manner, and the reflecting surface is connected to the ground in a conductive manner.

[0034] Further, the circuit board is an FR-4 board material with a dielectric coefficient in the range of 4.2-4.7.

[0035] Further, the circuit board is a rectangular board, the length L1 of the circuit board ranges from 510±5mm, the width W1 of the circuit board ranges from 420±5mm, and the thickness of the circuit board ranges from 1.5±0.1mm; the column array direction of the rectangular vibrator array is arranged along the width direction of the circuit board.

[0036] Further, the circuit board is provided with a plurality of mounting holes communicating with the front and back surfaces thereof.

[0037] The beneficial effects of the utility model are as follows: the rectangular vibrator array composed of 16 vibrator units is formed on the circuit board, each vibrator unit is a square structure with a right angle at two opposite corners, and after the shape and size of the vibrator unit are limited and the row array spacing and column array spacing of the rectangular vibrator array are set to specific sizes, the coaxial cable feeds each vibrator unit through the feed network with a specific size structure during application, so that the following electrical indicators can be obtained during application of the utility model: frequency range: 902-928MHz, gain: 8dBi, beam width: Hor: 38°, Ver: 37°, polarization mode: circular polarization, voltage standing wave ratio: ≤1.8, front-to-back ratio: ≥25, impedance: 50Ω, maximum input power: 100W. Therefore, the utility model has a small beam width, strong directivity, high gain, and strong directivity during application, so that misreading is less likely to occur during application, and the application effect is good; in addition, the utility model is composed of a single circuit board, so that the utility model also has the advantages of simple structure, light weight, and low production cost. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a front view structural schematic diagram of an embodiment.

[0039] Figure 2 It is a front view structural schematic diagram of an embodiment. Figure 1 It is an enlarged structural schematic diagram of part A.

[0040] Figure 3 It is a rear view structural schematic diagram of a circuit board of an embodiment.

[0041] Figure 4 It is a rear view structural schematic diagram of a circuit board of an embodiment. Figure 3 It is an enlarged structural schematic diagram of part B.

[0042] Figure 5 It is a horizontal plane radiation pattern during use of an embodiment.

[0043] Figure 6 It is a vertical plane radiation pattern during use of an embodiment.

[0044] Explanation of reference numerals in the attached diagram: 1-Circuit board; 11-Reflective surface; 12-Power supply connection area; 13-Copper via; 14-Power supply connection structure; 15-First connection end; 16-Second connection end; 17-Mounting hole; 2-Coaxial cable; 3-Iron element; 4-Power supply network; 41-First circuit; 42-Second circuit; 43-Third circuit; 44-Fourth circuit; 45-Fifth circuit; 46-Sixth circuit; 47-Seventh circuit; 51-First oscillator row; 52-Second oscillator row; 53-Third oscillator row; 54-Fourth oscillator row. Detailed Implementation

[0045] like Figure 1 As shown, this embodiment of a highly directional near-field antenna includes a circuit board 1 and a coaxial cable 2. The front side of the circuit board 1 is formed with copper plating to create a vibrating element 3 and a feed network 4. Each vibrating element 3 is a square with chamfered corners at two opposite points. The side length L of each vibrating element 3 is 80mm, the chamfer angle of each corner is 45°, and the chamfer distance between each corner is 13mm. There are 16 vibrating elements 3, arranged in a 4x4 rectangular array. In this rectangular array, the spacing D1 between adjacent columns of vibrating elements 3 is 58mm, and the spacing D2 between adjacent rows of vibrating elements 3 is 25mm.

[0046] The four rows of oscillator units 3 of the rectangular oscillator array are respectively called the first oscillator row 51, the second oscillator row 52, ​​the third oscillator row 53 and the fourth oscillator row 54; the first oscillator row 51, the second oscillator row 52, ​​the third oscillator row 53 and the fourth oscillator row 54 are arranged sequentially along the column array direction of the rectangular oscillator array;

[0047] The power supply network 4 includes a first circuit 41, a second circuit 42, a third circuit 43, a fourth circuit 44, a fifth circuit 45, a sixth circuit 46, and a seventh circuit 47.

[0048] The first circuit 41, the second circuit 42, the third circuit 43, and the fourth circuit 44 each include nine first straight line segments, namely A1, A2, A3, A4, A5, A6, A7, A8, and A9; the length directions of A1, A2, A3, A4, and A5 are all arranged along the row array direction of the rectangular oscillator array;

[0049] The length of A1 is 51mm and the width of A1 is 3mm; one end of A1 is connected to one end of A2 and is conductive, and the other end of A1 is connected to one end of A3 and is conductive.

[0050] A2 and A3 are each 42 mm in length and 5.5 mm in width; one end of A2 is connected to one end of A4, and one end of A3 is connected to one end of A5;

[0051] A4 and A5 are each 138 mm in length and 3 mm in width;

[0052] A6, A7, A8 and A9 are each 7 mm in length and 3 mm in width; A6, A7, A8 and A9 are all on the same side of A1; one end of A6 is connected to one end of A4 which is connected to A2, and one end of A7 is connected to one end of A4 which is away from A2; one end of A8 is connected to one end of A5 which is connected to A3, and one end of A9 is connected to one end of A5 which is away from A3;

[0053] The first circuit 41 is between the first row of oscillators 51 and the second row of oscillators 52; the four first straight line segments A6, A7, A8 and A9 of the first circuit 41 correspond to the four oscillator units 3 of the first row of oscillators 51 one by one, and the other ends of A6, A7, A8 and A9 of the first circuit 41 are connected to the middle positions of the side edges of the oscillator units 3 corresponding thereto which face the second row of oscillators 52;

[0054] The second circuit 42 is between the second row of oscillators 52 and the third row of oscillators 53; the four first straight line segments A6, A7, A8 and A9 of the second circuit 42 correspond to the four oscillator units 3 of the second row of oscillators 52 one by one, and the other ends of A6, A7, A8 and A9 of the second circuit 42 are connected to the middle positions of the side edges of the oscillator units 3 corresponding thereto which face the third row of oscillators 53;

[0055] The third circuit 43 is between the third row of oscillators 53 and the fourth row of oscillators 54; the four first straight line segments A6, A7, A8 and A9 of the third circuit 43 correspond to the four oscillator units 3 of the third row of oscillators 53 one by one, and the other ends of A6, A7, A8 and A9 of the third circuit 43 are connected to the middle positions of the side edges of the oscillator units 3 corresponding thereto which face the fourth row of oscillators 54;

[0056] The fourth circuit 44 is on the side of the fourth row of oscillators 54 which faces away from the third row of oscillators 53; the four first straight line segments A6, A7, A8 and A9 of the fourth circuit 44 correspond to the four oscillator units 3 of the fourth row of oscillators 54 one by one, and the other ends of A6, A7, A8 and A9 of the fourth circuit 44 are connected to the middle positions of the side edges of the oscillator units 3 corresponding thereto which face away from the third row of oscillators 53; the middle positions of the side edges of the oscillator units 3 in this embodiment are the middle positions of the side edges of the oscillator units 3 before chamfering.

[0057] The fifth circuit 45 is between the second circuit 42 and the third circuit 43, and the fifth circuit 45 comprises three second straight line segments, which are B1, B2 and B3 respectively;

[0058] The length direction of each of the B1, B2 and B3 is arranged along the column array direction of the rectangular element array; the line length of the B1 is 32 mm, the line width of the B1 is 3.5 mm, one end of the B1 is connected in conduction with one end of the B2, and the other end of the B1 is connected in conduction with one end of the B3;

[0059] The line length of each of the B2 and B3 is 35 mm, and the line width of each of the B2 and B3 is 8 mm; the other end of the B2 is connected in conduction with the center position in the length direction of the A1 of the second circuit 42 perpendicularly; the other end of the B3 is connected in conduction with the center position in the length direction of the A1 of the third circuit 43 perpendicularly;

[0060] The sixth circuit 46 and the seventh circuit 47 each comprise eight third straight line segments, which are C1, C2, C3, C4, C5, C6, C7 and C8 respectively; the C1, C2, C3, C4, C5, C6, C7 and C8 of each of the sixth circuit 46 and the seventh circuit 47 are connected in conduction in turn, and among the seven third straight line segments of the C2, C3, C4, C5, C6, C7 and C8: two adjacent third straight line segments are perpendicular to each other;

[0061] The length direction of each of the C1 and C2 is arranged along the column array direction of the rectangular element array; the line length of the C1 is 25 mm, and the line width of the C1 is 7 mm; the line length of the C2 is 27 mm, and the line width of each of the C2, C3, C4, C5, C6, C7 and C8 is 3.5 mm;

[0062] The line length of the C3 is 20 mm;

[0063] The line length of the C4 is 15 mm, and the C4 is on the side of the C3 away from the C2;

[0064] The line length of the C5 is 40 mm, and the C5 and the C3 are on the same side of the C4;

[0065] The line length of the C6 is 15 mm, and the C6 is on the side of the C5 away from the C4;

[0066] The line length of the C7 is 20 mm, and the C7 and the C5 are on the same side of the C6;

[0067] The line length of the C8 is 20 mm, and the C8 is on the side of the C7 away from the C6;

[0068] The sixth circuit 46 is between the first circuit 41 and the second circuit 42, the C1 of the sixth circuit 46 is connected to the center of the length direction of the A1 of the second circuit 42, and the C8 of the sixth circuit 46 is connected to the center of the length direction of the A1 of the first circuit 41;

[0069] The seventh circuit 47 is between the third circuit 43 and the fourth circuit 44, the C1 of the seventh circuit 47 is connected to the center of the length direction of the A1 of the third circuit 43, and the C8 of the seventh circuit 47 is connected to the center of the length direction of the A1 of the fourth circuit 44;

[0070] The inner conductor of the coaxial cable 2 is connected to the center of the length direction of the B1 of the fifth circuit 45, and the outer conductor of the coaxial cable 2 is connected to the ground.

[0071] In order to further optimize the strong directivity near-field antenna, in order to enhance the radiation intensity of the strong directivity near-field antenna in the specified direction, as shown in Figure 3 The back of the circuit board 1 is formed with a reflecting surface 11 by copper cladding.

[0072] In order to make the structure of the strong directivity near-field antenna more reasonable, as shown in Figure 1 、 Figure 3 、 Figure 4 The back of the circuit board 1 is formed with a feeding connection area 12 by copper cladding; the feeding connection area 12 is circular, the diameter φ of the feeding connection area 12 is 2.5mm, the feeding connection area 12 is insulated and separated from the reflecting surface 11; the feeding connection area 12 is connected to the center of the length direction of the B1 of the fifth circuit 45 through the copper sinking hole 13 formed on the circuit board 1; the model of the coaxial cable 2 of the embodiment is RG58, the inner conductor of the coaxial cable 2 is connected to the feeding connection area 12, the outer conductor of the coaxial cable 2 is connected to the reflecting surface 11, and the reflecting surface 11 is connected to the ground.

[0073] In addition, in order to make the strong directivity near-field antenna also be able to be connected to the coaxial cable with the model of RG316 for feeding, so that the user can select the coaxial cable with the model of RG316 or RG58 for feeding when using, as shown in Figure 1 、 Figure 2As shown in the figure, the front surface of the circuit board 1 is formed with a feed connection structure 14 by copper cladding; the feed connection structure 14 comprises a first connection end 15 and a second connection end 16; the first connection end 15 is insulated and separated from the second connection end 16, and the first connection end 15 is connected to the middle position of the length direction of B1 of the fifth circuit 45; the second connection end 16 is beside the first connection end 15, and the second connection end 16 is connected to the reflecting surface 11 through two copper cladding holes 13 formed on the circuit board 1; when the coaxial cable is of the type RG316, the inner conductor of the coaxial cable is connected to the first connection end 15, the outer conductor of the coaxial cable is connected to the second connection end 16, and the reflecting surface 11 is connected to the ground. In application, whether the coaxial cable is of the type RG316 or of the type RG58, the strong directivity near-field antenna can obtain the required electrical indicators.

[0074] As shown in the figure, Figure 1 , Figure 3 the circuit board 1 is an FR-4 board material with a dielectric coefficient of 4.5. The FR-4 board material has stable electrical insulation performance and good flatness, which facilitates the copper cladding production on the surface of the circuit board 1, and makes the production of the strong directivity near-field antenna easier.

[0075] As shown in the figure, Figure 1 the circuit board 1 is a rectangular board, the size of the length L1 of the circuit board 1 is 510 mm, the size of the width W1 of the circuit board 1 is 420 mm, and the size of the thickness of the circuit board 1 is 1.5 mm; the column array direction of the rectangular element array is arranged along the width direction of the circuit board 1. Such design can make the structure of the strong directivity near-field antenna more reasonable, and make the strong directivity near-field antenna achieve the preset electrical indicators when in use.

[0076] In order to facilitate the installation of the strong directivity near-field antenna, as shown in the figure, Figure 1 a plurality of mounting holes 17 are formed on the circuit board 1, which communicate with the front surface and the back surface.

[0077] The strong directivity near-field antenna can obtain the following electrical indicators when in use through the above design: frequency range: 902-928 MHz, gain: 8dBi, beam width: Hor: 38°, Ver: 37°, polarization mode: circular polarization, voltage standing wave ratio ≤1.8, front-to-back ratio ≥25, impedance: 50Ω, maximum input power: 100W. It can be seen that the strong directivity near-field antenna has small beam width, strong directivity, high gain, and strong directivity when in use, so that it is not easy to appear misreading phenomenon when in use, and the application effect is good; in addition, the strong directivity near-field antenna is only composed of a single circuit board 1, which also makes the strong directivity near-field antenna have the advantages of simple structure, light weight and low production cost. The strong directivity near-field antenna can obtain the following electrical indicators when in use:Figure 5 the horizontal plane radiation pattern and the vertical plane radiation pattern as Figure 6 shown.

Claims

1. A highly directional near-field antenna comprising a circuit board and a coaxial cable; characterized by: The front side of the circuit board is formed with a vibrator unit and a feed network by a copper cladding method; the vibrator unit is a square with two opposite corner positions formed with chamfers, each side length L of the vibrator unit is 80±3mm, the chamfer angle of each chamfer of the vibrator unit is 45°, and the chamfer distance range of each chamfer of the vibrator unit is 13±1mm; the number of the vibrator units is 16, and the 16 vibrator units are distributed to form a rectangular vibrator array of 4 rows and 4 columns; in the rectangular vibrator array: the size range of the spacing D1 between each two adjacent columns of vibrator units is 58±2mm, and the size range of the spacing D2 between each two adjacent rows of vibrator units is 25±2mm; The 4 rows of vibrator units of the rectangular vibrator array are respectively referred to as a first vibrator row, a second vibrator row, a third vibrator row and a fourth vibrator row; the first vibrator row, the second vibrator row, the third vibrator row and the fourth vibrator row are arranged in sequence along the column array direction of the rectangular vibrator array; The feed network comprises a first circuit, a second circuit, a third circuit, a fourth circuit, a fifth circuit, a sixth circuit and a seventh circuit; The first circuit, the second circuit, the third circuit and the fourth circuit each comprise 9 first straight line segments, and the 9 first straight line segments are respectively A1, A2, A3, A4, A5, A6, A7, A8 and A9; the length direction of each of A1, A2, A3, A4 and A5 is arranged along the row array direction of the rectangular vibrator array; The line length range of A1 is 51±2mm, and the line width range of A1 is 3±0.5mm; one end of A1 is connected in conduction with one end of A2, and the other end of A1 is connected in conduction with one end of A3; The line length range of each of A2 and A3 is 42±2mm, and the line width range of each of A2 and A3 is 5.5±0.5mm; the other end of A2 is connected in conduction with one end of A4, and the other end of A3 is connected in conduction with one end of A5; The line length range of each of A4 and A5 is 138±2mm, and the line width range of each of A4 and A5 is 3±0.5mm; The line length range of each of A6, A7, A8 and A9 is 7±0.5mm, and the line width range of each of A6, A7, A8 and A9 is 3±0.5mm; A6, A7, A8 and A9 are all on the same side of A1; one end of A6 is connected in conduction with the end of A4 which is perpendicular to A2, and one end of A7 is connected in conduction with the end of A4 which is away from A2; one end of A8 is connected in conduction with the end of A5 which is perpendicular to A3, and one end of A9 is connected in conduction with the end of A5 which is away from A3; The first circuit is between the first vibrator row and the second vibrator row; the four first straight line segments A6, A7, A8 and A9 of the first circuit correspond one-to-one to the four vibrator units of the first vibrator row, and the other end of each of A6, A7, A8 and A9 of the first circuit is connected in conduction with the middle position of the side of the vibrator unit corresponding thereto which faces the second vibrator row. The second circuit is between the second row of vibrators and the third row of vibrators; the four first straight line segments A6, A7, A8 and A9 of the second circuit correspond to the four vibrator units of the second row of vibrators one by one, and the other ends of A6, A7, A8 and A9 of the second circuit are connected in perpendicular to the middle positions of the side edges of the vibrator units corresponding thereto facing the third row of vibrators; The third circuit is between the third row of vibrators and the fourth row of vibrators; the four first straight line segments A6, A7, A8 and A9 of the third circuit correspond to the four vibrator units of the third row of vibrators one by one, and the other ends of A6, A7, A8 and A9 of the third circuit are connected in perpendicular to the middle positions of the side edges of the vibrator units corresponding thereto facing the fourth row of vibrators; The fourth circuit is on the side of the fourth row of vibrators facing away from the third row of vibrators; the four first straight line segments A6, A7, A8 and A9 of the fourth circuit correspond to the four vibrator units of the fourth row of vibrators one by one, and the other ends of A6, A7, A8 and A9 of the fourth circuit are connected in perpendicular to the middle positions of the side edges of the vibrator units corresponding thereto facing away from the third row of vibrators; The fifth circuit is between the second circuit and the third circuit, and the fifth circuit includes three second straight line segments B1, B2 and B3; The length directions of B1, B2 and B3 are arranged along the column array direction of the rectangular vibrator array; the length of B1 ranges from 32±1mm, the width of B1 ranges from 3.5±0.5mm, one end of B1 is connected in conductive manner to one end of B2, and the other end of B1 is connected in conductive manner to one end of B3; The length of B2 ranges from 35±1mm, and the width of B2 ranges from 8±0.5mm; the other end of B2 is connected in perpendicular to the center position of the length direction of A1 of the second circuit; the other end of B3 is connected in perpendicular to the center position of the length direction of A1 of the third circuit; The sixth circuit and the seventh circuit each include eight third straight line segments C1, C2, C3, C4, C5, C6, C7 and C8; C1, C2, C3, C4, C5, C6, C7 and C8 of the sixth circuit and the seventh circuit are connected in conductive manner in sequence, and among the seven third straight line segments C2, C3, C4, C5, C6, C7 and C8, two adjacent third straight line segments are perpendicular to each other; The length directions of C1 and C2 are arranged along the column array direction of the rectangular vibrator array; the length of C1 ranges from 25±1mm, and the width of C1 ranges from 7±0.5mm; the length of C2 ranges from 27±1mm, and the width of C2, C3, C4, C5, C6, C7 and C8 ranges from 3.5±0.5mm; The length of C3 ranges from 20±1mm; The length of C4 ranges from 15±1mm, and C4 is on the side of C3 facing away from C2; The length of C5 ranges from 40±1mm, and C5 and C3 are on the same side of C4; The length of C6 ranges from 15±1mm, and C6 is on the side of C5 facing away from C4; The line length of C7 ranges from 20±1mm, and C7 and C5 are on the same side of C6; The line length of C8 ranges from 20±1mm, and C8 is on the side of C7 away from C6; The sixth circuit is between the first circuit and the second circuit, and the end of C1 of the sixth circuit away from C2 is connected to the center of A1 of the second circuit in the length direction to conduct, and the end of C8 of the sixth circuit away from C7 is connected to the center of A1 of the first circuit in the length direction to conduct; The seventh circuit is between the third circuit and the fourth circuit, and the end of C1 of the seventh circuit away from C2 is connected to the center of A1 of the third circuit in the length direction to conduct, and the end of C8 of the seventh circuit away from C7 is connected to the center of A1 of the fourth circuit in the length direction to conduct; The inner conductor of the coaxial cable is connected to the middle of B1 of the fifth circuit in the length direction to conduct, and the outer conductor of the coaxial cable is connected to the ground to conduct.

2. The highly directional near-field antenna of claim 1, wherein: The back of the circuit board is formed with a reflecting surface by copper cladding.

3. The highly directional near-field antenna of claim 2, wherein: The back of the circuit board is further formed with a feeding connection area by copper cladding; the feeding connection area is circular, the diameter φ of the feeding connection area is 2.5±0.1mm, the feeding connection area is insulated and separated from the reflecting surface; the feeding connection area is connected to the middle of B1 of the fifth circuit in the length direction through a copper sinking hole formed on the circuit board; the model of the coaxial cable is RG58, the inner conductor of the coaxial cable is connected to the feeding connection area to conduct, the outer conductor of the coaxial cable is connected to the reflecting surface to conduct, and the reflecting surface is connected to the ground to conduct.

4. The highly directional near-field antenna of claim 2, wherein: The front of the circuit board is formed with a feeding connection structure by copper cladding; the feeding connection structure includes a first connection end and a second connection end; the first connection end and the second connection end are insulated and separated, and the first connection end is connected to the middle of B1 of the fifth circuit in the length direction to conduct; the second connection end is beside the first connection end, and the second connection end and the reflecting surface are connected through two copper sinking holes formed on the circuit board to conduct; the model of the coaxial cable is RG316, the inner conductor of the coaxial cable is connected to the first connection end to conduct, the outer conductor of the coaxial cable is connected to the second connection end to conduct, and the reflecting surface is connected to the ground to conduct.

5. The highly directional near-field antenna of claim 1, wherein: The circuit board is an FR-4 board material with a dielectric coefficient ranging from 4.2 to 4.

7.

6. The highly directional near-field antenna of claim 2, wherein: The circuit board is a rectangular board, the length L1 of the circuit board ranges from 510±5mm, the width W1 of the circuit board ranges from 420±5mm, and the thickness of the circuit board ranges from 1.5±0.1mm; the column array direction of the rectangular transducer array is arranged along the width direction of the circuit board.

7. The highly directional near-field antenna of claim 1, wherein: The circuit board is formed with a plurality of mounting holes communicating with the front and back surfaces thereof.

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