Near-field antenna with uniform electromagnetic wave surface emission

Abstract

The utility model relates to a near-field antenna with uniform electromagnetic wave surface emission. The near-field antenna comprises a circuit board and a coaxial cable, a feed transmission circuit and six oscillator groups are formed on the front surface of the circuit board; each oscillator group comprises a phase adjusting circuit and four oscillator units; the four oscillator units of each oscillator group are distributed in a circular array by taking the center of the corresponding oscillator group as an array center; the six oscillator groups are transversely arranged in a row in an array manner; each vibrator unit is in a square frame shape; each oscillator unit is internally provided with a C-shaped non-copper-clad area. The C-shaped non-copper-clad region is arranged in a manner of half surrounding the inner contour of the oscillator unit; four output connecting ends of the phase adjusting circuit of each oscillator group are connected and conducted with the four oscillator units in a one-to-one correspondence manner; the coaxial cable is connected and conducted with the phase adjusting circuit of each oscillator group through the feed transmission circuit, and the 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, high gain, uniform electromagnetic wave surface emission and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of RFID application technology, especially a near field antenna of electromagnetic wave surface emission uniformity. BACKGROUND

[0002] The near field antenna is a kind of antenna specially designed for working in the near field area of electromagnetic field, and its core function is to realize energy transmission or short-distance communication through electromagnetic induction or magnetic coupling.In application, the reader with near field antenna can emit electromagnetic wave, so that the reader can communicate with RFID tag on the object in the electromagnetic wave covered area, and then complete the reading of RFID tag.At present, the electromagnetic wave surface emission of near field antenna on the market is not uniform enough, so that when using, it cannot ensure that the tag or equipment can be reliably coupled in each position in the electromagnetic wave covered area of near field antenna, which affects the reading efficiency of near field antenna in application, and the application effect is poor. UTILITY MODEL CONTENT

[0003] The utility model aims at providing a kind of near field antenna of electromagnetic wave surface emission uniformity, which has the advantages of simple structure, scientific design, low production cost, high gain and uniform electromagnetic wave surface emission.

[0004] The technical scheme of the utility model is realized as follows: a kind of near field antenna of electromagnetic wave surface emission uniformity, including circuit board and coaxial cable;Particularly, feed transmission circuit and 6 oscillator groups are formed in the way of copper cladding on the front of circuit board;

[0005] Each oscillator group includes phase adjustment circuit and 4 oscillator units;4 oscillator units of each oscillator group are circularly arrayed with the center of the oscillator group as array center, the size range of the distance D1 between the center of each oscillator unit and array center is 70±2mm, and 2 oscillator units of each oscillator group are arranged in a row transversely, and another 2 oscillator units are arranged in another row transversely;6 oscillator groups are arranged in a row transversely, and the size range of the distance D2 between each adjacent 2 oscillator groups is 13±1mm;

[0006] Each oscillator unit is square frame shape;The size range of each side length L1 of the inner contour of oscillator unit is 29.5±1mm;The size range of each side length L2 of the outer contour of oscillator unit is 70±2mm, and chamfer is formed at 2 opposite corner positions of the outer contour of oscillator unit, the chamfer angle of the chamfer is 45°, and the chamfer distance range is 13±1mm;One chamfer of each oscillator unit of each oscillator group is arranged close to the center of the oscillator group;

[0007] The C-shaped non-copper covering area is arranged in a half-enclosing inner contour of the vibrator unit, and the C-shaped non-copper covering area is composed of five straight line areas, which are A1, A2, A3, A4 and A5 respectively;

[0008] The length direction of A1 is parallel to one side of the outer contour of the vibrator unit, the length range of A1 is 31±1mm, and the width range of A1 is 3±0.1mm;

[0009] The length direction of A2 is parallel to the fillet of the vibrator unit away from the center of the vibrator group to which the vibrator unit belongs, the size range of the interval D3 between A2 and the fillet of the vibrator unit away from the center of the vibrator group to which the vibrator unit belongs is 10±0.1mm, the length range of A2 is 10±1mm, and the width range of A2 is 3.5±0.1mm;

[0010] The length direction of A3 is perpendicular to the length direction of A1, the length range of A3 is 43±1mm, the width range of A3 is 4±0.1mm, and A3 is connected to the center of one side of the inner contour of the vibrator unit through a straight line non-copper covering area; the length direction of the straight line non-copper covering area is perpendicular to the length direction of A3, the length range of the straight line non-copper covering area is 6.5±0.1mm, and the width range of the straight line non-copper covering area is 5±0.1mm;

[0011] The length direction of A4 is perpendicular to the length direction of A3, the length range of A4 is 38±1mm, and the width range of A4 is 3±0.1mm;

[0012] The length direction of A5 is parallel to the fillet of the vibrator unit close to the center of the vibrator group to which the vibrator unit belongs, the length range of A5 is 10±1mm, and the width range of A5 is 4±0.1mm;

[0013] The phase adjustment circuit of each vibrator group is formed with an input connection end and four output connection ends; each adjacent two vibrator units in each vibrator group are respectively provided with one of the output connection ends, the four output connection ends are circularly arrayed with the center of the vibrator group as the array center, and the phases of the signals output by the four output connection ends are sequentially different by 90° when the four output connection ends are used; the four output connection ends of each vibrator group correspond to the four vibrator units one by one, and the corresponding output connection end is connected and conducted with the center of the side of the outer contour of the vibrator unit opposite to the opening of the C-shaped non-copper covering area;

[0014] The feeding transmission circuit is formed with a feeding input end and six feeding output ends; the phases of the signals output by all the feeding output ends are the same when all the feeding output ends are used, all the feeding output ends correspond to all the vibrator groups one by one, and the corresponding feeding output end is connected and conducted with the input connection end of the vibrator group;

[0015] The inner conductor of the coaxial cable is connected to the feed input end of the feed transmission circuit, and the outer conductor of the coaxial cable is connected to the ground.

[0016] The 24 square frame-shaped resonator units with C-shaped non-coppered areas are formed on the circuit board in a copper-clad manner, the 24 resonator units are evenly divided into 6 groups, each group of 4 resonator units is arranged in a circular array to form a resonator group, and the 6 resonator groups are arranged in a horizontal array, so that the electromagnetic wave surface emission is uniform when the resonator unit is applied, and the label or device can be reliably coupled at different positions in the area covered by the resonator unit, thereby further improving the reading efficiency. In addition, a non-coppered area formed by the C-shaped non-coppered area and the inner contour of the resonator unit is formed in each resonator unit, which effectively improves the gain and bandwidth of the resonator unit in use, so that the resonator unit can also obtain the following electrical indicators when applied: frequency range: 902-928MHz, gain: 1.7dBi, beam width: Hor: 75°, Ver: 14°, polarization mode: circular polarization, voltage standing wave ratio: ≤1.5, front-to-back ratio: ≥17, impedance: 50Ω, maximum input power: 50W. Therefore, the resonator unit has the advantages of wide horizontal beam coverage and narrow vertical coverage when applied, and is very suitable for application in RFID logistics tracking and warehouse.

[0017] Further, the back surface of the circuit board is formed in a copper-clad manner.

[0018] Further, the circuit board is an FR-4 board with a dielectric coefficient in the range of 4.2-4.7.

[0019] Further, the circuit board is a rectangular board, the length L of the circuit board ranges from 1100±5mm, the width W of the circuit board ranges from 200±5mm, and the thickness of the circuit board ranges from 1.5±0.1mm; all resonator groups are arranged in an array along the length direction of the circuit board.

[0020] Further, a plurality of mounting holes are formed on the circuit board and communicate with the front surface and the back surface.

[0021] The utility model discloses the beneficial effects of having the advantages of simple structure, scientific design, low production cost, high gain and uniform electromagnetic wave surface emission. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a front view structural schematic diagram of the embodiment.

[0023] Figure 2 A schematic view of the back structure of the circuit board of the embodiment.

[0024] Figure 3 A schematic view of the structure of the vibrator group of the embodiment.

[0025] Figure 4 A horizontal plane radiation pattern of the embodiment in use.

[0026] Figure 5 A vertical plane radiation pattern of the embodiment in use.

[0027] BRIEF DESCRIPTION OF THE DRAWINGS: 1-circuit board; 11-reflective surface; 12-mounting hole; 2-coaxial cable; 3-feed transmission circuit; 31-feed input end; 32-feed output end; 4-vibrator group; 5-phase adjustment circuit; 51-input connection end; 52-first output connection end; 53-second output connection end; 54-third output connection end; 55-fourth output connection end; 6-vibrator unit; 61-C-shaped non-copper-clad area; 62-straight non-copper-clad area. DETAILED DESCRIPTION

[0028] As shown in Figure 1 , Figure 2 , Figure 3 , an electromagnetic wave surface-emitting uniform near-field antenna of the embodiment comprises a circuit board 1 and a coaxial cable 2; a feed transmission circuit 3 and six vibrator groups 4 are formed on the front surface of the circuit board 1 in a copper-clad manner;

[0029] Each vibrator group 4 comprises a phase adjustment circuit 5 and four vibrator units 6; the four vibrator units 6 of each vibrator group 4 are distributed in a circular array with the center of the vibrator group 4 as the array center M, the distance D1 between the center N of each vibrator unit 6 and the array center M is 70 mm, and two of the vibrator units 6 of each vibrator group 4 are arranged in a row in the lateral direction, and the other two vibrator units 6 are arranged in another row in the lateral direction; the six vibrator groups 4 are arranged in a row in the lateral direction, and the distance D2 between each adjacent two vibrator groups 4 is 13 mm;

[0030] Each vibrator unit 6 is a square frame; the length L1 of each side of the inner contour of the vibrator unit 6 is 29.5 mm; the length L2 of each side of the outer contour of the vibrator unit 6 is 70 mm, and a chamfer is formed at two opposite corner positions of the outer contour of the vibrator unit 6, the chamfer angle of the chamfer is 45°, and the chamfer distance is 13 mm; one chamfer of each vibrator unit 6 of each vibrator group 4 is arranged close to the center of the vibrator group 4;

[0031] Each of the vibrator units 6 is provided with a C-shaped non-copper covering area 61; the C-shaped non-copper covering area 61 is arranged in a semi-enclosing inner contour of the vibrator unit 6, and the C-shaped non-copper covering area 61 is composed of five straight line areas, which are A1, A2, A3, A4 and A5 respectively;

[0032] The length direction of A1 is parallel to one side of the outer contour of the vibrator unit 6, the length of A1 is 31 mm, and the width of A1 is 3 mm;

[0033] The length direction of A2 is parallel to the fillet of the vibrator unit 6 away from the center of the vibrator group 4 to which the vibrator unit 6 belongs, the distance D3 between A2 and the fillet of the vibrator unit 6 away from the center of the vibrator group 4 to which the vibrator unit 6 belongs is 10 mm, the length of A2 is 10 mm, and the width of A2 is 3.5 mm;

[0034] The length direction of A3 is perpendicular to the length direction of A1, the length of A3 is 43 mm, the width of A3 is 4 mm, and A3 is connected to the center of one side of the inner contour of the vibrator unit 6 through a straight line non-copper covering area 62; the length direction of the straight line non-copper covering area 62 is perpendicular to the length direction of A3, the length of the straight line non-copper covering area 62 is 6.5 mm, and the width of the straight line non-copper covering area 62 is 5 mm;

[0035] The length direction of A4 is perpendicular to the length direction of A3, the length of A4 is 38 mm, and the width of A4 is 3 mm;

[0036] The length direction of A5 is parallel to the fillet of the vibrator unit 6 close to the center of the vibrator group 4 to which the vibrator unit 6 belongs, the length of A5 is 10 mm, and the width of A5 is 4 mm;

[0037] The phase adjustment circuit 5 of each of the vibrator groups 4 is formed with an input connection end 51 and four output connection ends; each of the adjacent two vibrator units 6 in each of the vibrator groups 4 is respectively provided with one of the output connection ends, the four output connection ends are circularly arrayed with the center of the vibrator group 4 as the array center, and the phases of the signals output by the four output connection ends are sequentially different by 90° when in use, the four output connection ends are a first output connection end 52, a second output connection end 53, a third output connection end 54 and a fourth output connection end 55 respectively, the signal phase of the first output connection end 52 is 0° when in use, the signal phase of the second output connection end 53 is 90°, the signal phase of the third output connection end 54 is 180°, and the signal phase of the fourth output connection end 55 is 270°; the four output connection ends of each of the vibrator groups 4 correspond to the four vibrator units 6 one by one, and the corresponding output connection end is connected to the center of the side of the outer contour of the vibrator unit 6 opposite to the opening of the C-shaped non-copper covering area 61, and the center of the side of the outer contour of the vibrator unit 6 refers to the middle position of the side of the outer contour of the vibrator unit 6 before the fillet;

[0038] The power supply transmission circuit 3 has a power supply input terminal 31 and six power supply output terminals 32. When all power supply output terminals 32 are in use, the output signals have the same phase. All power supply output terminals 32 correspond one-to-one with all oscillator groups 4. The corresponding power supply output terminal 32 is connected to the input connection terminal 51 of the oscillator group 4.

[0039] The inner conductor of the coaxial cable 2 is connected to the feed input terminal 31 of the feed transmission circuit 3, and the outer conductor of the coaxial cable 2 is connected to the ground. This design ensures uniform electromagnetic wave emission from the near-field antenna during application, guaranteeing reliable coupling of tags or devices at different locations within the coverage area of ​​the near-field antenna, further improving readout efficiency. Furthermore, the structure formed in each vibrator element 1, consisting of a C-shaped non-copper-clad region 61 connected to the inner contour of the vibrator element 1, effectively improves the gain and bandwidth of the near-field antenna during use.

[0040] To further optimize this near-field antenna and enhance its radiation intensity in a specified direction, such as... Figure 2 As shown, a reflective surface 11 is formed on the back of the circuit board 1 by copper plating.

[0041] Circuit board 1 is made of FR-4 substrate with a dielectric constant in the range of 4.2 to 4.7. FR-4 substrate has stable electrical insulation properties and good flatness, which facilitates copper plating on the surface of circuit board 1, making the production of this near-field antenna easier.

[0042] like Figure 1 , Figure 2 As shown, circuit board 1 is a rectangular board with a length L of 1100mm, a width W of 200mm, and a thickness of 1.5mm. All vibrator groups 4 are arranged in an array along the length of circuit board 1. This design makes the structure of this near-field antenna more reasonable, with advantages such as small size, light weight, and the ability to meet preset electrical specifications during use.

[0043] To facilitate the installation of this near-field antenna, such as Figure 1 , Figure 2 As shown, the circuit board 1 has several mounting holes 12 that connect its front and back sides.

[0044] This near-field antenna, through the above design, also achieves the following electrical specifications in application: frequency range: 902~928MHz, gain: 1.7dBi, beamwidth: Horn: 75°, Ver: 14°, polarization: circular polarization, voltage standing wave ratio ≤1.5, front-to-back ratio ≥17, impedance: 50Ω, maximum input power: 50W; This near-field antenna can achieve the following in use: Figure 4the horizontal plane radiation pattern and the vertical plane radiation pattern shown in Figure 5 ; thus, it is known that the present near-field antenna has the advantages of wide horizontal direction beam coverage and narrow vertical direction beam coverage when applied, so that the present near-field antenna is very suitable for application in RFID logistics tracking and warehouse; in addition, the present near-field antenna is only composed of a single printed circuit board 1, so that the present near-field antenna also has the advantages of simple structure, light weight and low production cost.

Claims

1. A near-field antenna with uniform electromagnetic wave surface emission, comprising a circuit board and a coaxial cable; characterized in that: The feeding transmission circuit and six vibrator groups are formed on the front surface of the circuit board in a copper-clad manner; Each of the vibrator groups comprises a phase adjusting circuit and four vibrator units; the four vibrator units of each of the vibrator groups are circularly arrayed with the center of the vibrator group as the array center, the distance D1 between the center of each of the vibrator units and the array center ranges from 70 mm to 72 mm, and two of the vibrator units of each of the vibrator groups are arranged in a row in the transverse direction and the other two of the vibrator units are arranged in another row in the transverse direction; the six vibrator groups are arranged in a row in the transverse direction, and the distance D2 between each of the adjacent two of the vibrator groups ranges from 13 mm to 14 mm; Each of the vibrator units is in the shape of a square frame; the length L1 of each of the sides of the inner contour of the vibrator unit ranges from 29.5 mm to 31 mm; the length L2 of each of the sides of the outer contour of the vibrator unit ranges from 70 mm to 72 mm, and a chamfer is formed at each of the two opposite corner positions of the outer contour of the vibrator unit, the chamfer angle of the chamfer is 45°, and the distance of the chamfer ranges from 13 mm to 14 mm; one of the chamfers of each of the vibrator units is arranged close to the center of the vibrator group to which the vibrator unit belongs; Each of the vibrator units is provided with a C-shaped non-copper-clad area; the C-shaped non-copper-clad area is arranged in a semi-surrounding manner on the inner contour of the vibrator unit, and the C-shaped non-copper-clad area is composed of five linear areas, i.e., A1, A2, A3, A4 and A5; The length direction of A1 is parallel to one of the sides of the outer contour of the vibrator unit, the length of A1 ranges from 31 mm to 32 mm, and the width of A1 ranges from 3 mm to 3.1 mm; The length direction of A2 is parallel to the chamfer of the vibrator unit away from the center of the vibrator group to which the vibrator unit belongs, the distance D3 between A2 and the chamfer of the vibrator unit away from the center of the vibrator group to which the vibrator unit belongs ranges from 10 mm to 10.1 mm, the length of A2 ranges from 10 mm to 11 mm, and the width of A2 ranges from 3.5 mm to 3.6 mm; The length direction of A3 is perpendicular to the length direction of A1, the length of A3 ranges from 43 mm to 44 mm, the width of A3 ranges from 4 mm to 4.1 mm, and A3 is in communication with the center of one of the sides of the inner contour of the vibrator unit through a linear non-copper-clad area; the length direction of the linear non-copper-clad area is perpendicular to the length direction of A3, the length of the linear non-copper-clad area ranges from 6.5 mm to 6.6 mm, and the width of the linear non-copper-clad area ranges from 5 mm to 5.1 mm; The length direction of A4 is perpendicular to the length direction of A3, the length of A4 ranges from 38 mm to 39 mm, and the width of A4 ranges from 3 mm to 3.1 mm; The length direction of A5 is parallel to the chamfer of the vibrator unit close to the center of the vibrator group to which the vibrator unit belongs, the length of A5 ranges from 10 mm to 11 mm, and the width of A5 ranges from 4 mm to 4.1 mm. The phase adjusting circuit of each oscillator group is formed with an input connection end and four output connection ends; each of the adjacent two oscillator units in each oscillator group is provided with one of the output connection ends, the four output connection ends are circularly arrayed with the center of the oscillator group as the array center, and the phases of the signals output by the four output connection ends are sequentially different by 90°; the four output connection ends of each oscillator group correspond to the four oscillator units one by one, and the corresponding output connection end is connected in conduction with the center of the side of the outer contour of the oscillator unit which is opposite to the opening of the C-shaped non-copper clad area; The feeding transmission circuit is formed with a feeding input end and six feeding output ends; the phases of the signals output by all the feeding output ends are the same when all the feeding output ends are used, all the feeding output ends correspond to all the oscillator groups one by one, and the corresponding feeding output end is connected in conduction with the input connection end of the oscillator group; The inner conductor of the coaxial cable is connected in conduction with the feeding input end of the feeding transmission circuit, and the outer conductor of the coaxial cable is connected in conduction with the ground.

2. The near-field antenna of claim 1, wherein: The back surface of the circuit board is formed with a reflecting surface in a copper clad manner.

3. The near-field antenna of claim 1, wherein: The circuit board is an FR-4 board material with a dielectric coefficient in the range of 4.2-4.

7.

4. The near-field antenna of claim 2, wherein: The circuit board is a rectangular board, the size of the length L of the circuit board ranges from 1100±5mm, the size of the width W of the circuit board ranges from 200±5mm, and the size of the thickness of the circuit board ranges from 1.5±0.1mm; all the oscillator groups are arrayed along the length direction of the circuit board.

5. The near-field antenna of claim 1 wherein: the electromagnetic wave surface launch is uniform. The circuit board is formed with a plurality of mounting holes which communicate with the front surface and the back surface thereof.

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