CN112310609A - Low-profile wide-beam circularly polarized reader antenna applied to RFID - Google Patents
Low-profile wide-beam circularly polarized reader antenna applied to RFID Download PDFInfo
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- CN112310609A CN112310609A CN202011339248.2A CN202011339248A CN112310609A CN 112310609 A CN112310609 A CN 112310609A CN 202011339248 A CN202011339248 A CN 202011339248A CN 112310609 A CN112310609 A CN 112310609A
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- 230000005855 radiation Effects 0.000 claims abstract description 63
- 230000008878 coupling Effects 0.000 claims abstract description 32
- 238000010168 coupling process Methods 0.000 claims abstract description 32
- 238000005859 coupling reaction Methods 0.000 claims abstract description 32
- 239000000758 substrate Substances 0.000 claims abstract description 21
- 230000003071 parasitic effect Effects 0.000 claims abstract description 18
- 230000010287 polarization Effects 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 9
- 238000004088 simulation Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 230000005684 electric field Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004807 localization Effects 0.000 description 1
- 238000013068 supply chain management Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
- H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/48—Earthing means; Earth screens; Counterpoises
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- Waveguide Aerials (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
The invention provides a low-profile wide-beam circularly polarized reader antenna applied to RFID (radio frequency identification devices), which comprises a grounding plate (2) internally provided with a radiation device cavity; the radiation device cavity is a rectangular cavity in which a medium substrate (1) is arranged; a radiation patch (3) is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in the shape in the plane view; the polygonal ring and the middle parts of four sides of the rectangular cavity, which are parallel to the four side walls, are provided with concave structures; the four side walls of the rectangular cavity are connected with the initial end of the coupling parasitic patch (4); the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is close to the edge of the radiation welt and extends into the concave structure of the polygonal annular edge of the radiation patch; the invention can cover RFID frequency band, has low section and directional radiation, has axial ratio less than 3dB in the maximum radiation direction, has circular polarization and 3dB axial ratio beam width, and is suitable for being applied to mobile terminal equipment.
Description
Technical Field
The invention relates to the technical field of antennas, in particular to a low-profile wide-beam circularly polarized reader antenna applied to RFID.
Background
In recent years, Radio Frequency Identification (RFID) has become very popular in many application areas such as logistics, supply chain management, asset tracking and vehicle localization. The use of different rf frequencies and technologies in various uhf passive rfid systems has received much attention due to its many advantages, including cost, size and long read range. Circularly polarized antennas are widely used in various wireless communication systems, such as radio frequency identification, global navigation satellite systems, etc., because they are effective against polarization mismatch and multipath interference. As is known, circular polarization radiation can be obtained by exciting two orthogonal electric field components with equal amplitude and 90-degree phase difference, and currently, the common methods mainly include a multi-feed method and a single-feed method. For the RFID reader antenna, the wider the beam width, the wider the range of the antenna that can effectively identify the electronic tag. Therefore, when designing a reader antenna, attention needs to be paid to the beam width of the antenna, or the range of the electronic tag needs to be extended by beam scanning. In addition to the improvement of performance and quality, the RFID antenna is developed toward broadband and multi-frequency applications, and the specific manufacturing technology is developed toward miniaturization, planarization and easy manufacturing. Therefore, the research on the miniaturized loop antenna has wide application prospect in the RFID system.
Disclosure of Invention
The invention provides a low-profile wide-beam circularly polarized reader antenna applied to RFID, which can cover RFID frequency bands, has low profile and directional radiation, has the axial ratio in the maximum radiation direction smaller than 3dB, has circular polarization and a 3dB axial ratio and is wide in beam width, and is suitable for being applied to mobile terminal equipment.
The invention adopts the following technical scheme.
A low profile wide beam circularly polarised reader antenna for use with RFID, the reader antenna comprising a ground plate (2) having a cavity for a radiating device built into it; the radiation device cavity is a rectangular cavity in which a medium substrate (1) is arranged; a radiation patch (3) is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in the shape in the plane view; the polygonal ring and the middle parts of four sides of the rectangular cavity, which are parallel to the four side walls, are provided with concave structures; the four side walls of the rectangular cavity are connected with the initial end of the coupling parasitic patch (4); the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is close to the edge of the radiation welt and extends into the concave structure of the polygonal annular edge of the radiation patch.
The grounding plate is of an all-metal structure; the periphery of the grounding plate is provided with a foldable folding structure (21); the folded structure of the ground plate forms a sidewall of the radiating device cavity when the folded structure is in the upwardly folded configuration.
And a rectangular metal strip (22) used for connecting the starting end of the coupling parasitic patch is arranged at the upper part of the side wall of the radiation device cavity.
The radiation patch is a patch structure printed on the dielectric substrate; the reader antenna further comprises a feed structure (5) printed at the lower surface of the dielectric substrate.
The top view shape of the feed structure comprises two isosceles triangles of different sizes and perpendicularly intersecting at a vertex.
The feed structure and the radiation patch form a feed coupling structure; the perimeter of the polygonal ring of the radiating patch is close to or equal to the wavelength of the antenna beam; when the length of the polygonal ring is changed, the resonant frequency point of the radiating patch is changed; the feed structure is connected with the radiation patch by a coaxial cable (6); the feed coupling structure forms a phase difference by using a coupling area difference between the feed structure and the radiation patch; the phase difference may form a horizontal current and a vertical current in the antenna to circularly polarize the beam radiated from the antenna.
The coupling parasitic patch and the four concave structures of the radiation patch form a small coupling structure with a capacitor in a four-arrow-shaped structure, and the beam width of the antenna can be enlarged by the small coupling structure with the capacitor.
An air layer (7) is arranged between the dielectric substrate and the cavity bottom of the grounding plate radiation device.
The RFID reader antenna has the advantages that the wave beam frequency band of the reader antenna covers the RFID frequency band, the axial ratio of the wave beam in the maximum radiation direction is less than 3dB, the reader antenna has a circular polarization characteristic, and the wave beam width is wider than the 3dB axial ratio.
The reader antenna is used for mobile terminal equipment.
Compared with the prior art, the invention has the following advantages: the antenna has a simple structure, is easy to process, realizes directional radiation, enables the antenna to have higher gain in the maximum radiation direction and has circular polarization in the direction.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
FIG. 1 is a perspective view of an antenna according to the present invention;
FIG. 2 is a schematic side view of an antenna according to the present invention;
fig. 3 is a schematic front view of an antenna according to the present invention;
fig. 4 is a schematic perspective view of a ground plane of the antenna of the present invention;
fig. 5 is a schematic view of an area where a front view radiating patch of the antenna of the present invention is located;
fig. 6 is a schematic diagram of the area where the arrow-shaped coupling parasitic patch of the antenna of the present invention is located;
fig. 7 is a schematic diagram of an area where an isosceles triangle feed structure of a front view of the antenna of the present invention is located;
FIG. 8 is a schematic diagram of a 3dB axial ratio beam width simulation of the antenna of the present invention;
fig. 9 is a simulation diagram of the antenna S11 according to the present invention;
FIG. 10 is a schematic diagram of an antenna axial ratio simulation according to the present invention;
fig. 11 is a schematic view of actually measured and simulated radiation directions of a Phi =0 ° plane at a frequency of 922 MHz of the antenna of the present invention;
fig. 12 is a schematic view of the measured and simulated radiation direction of the Phi =90 ° plane at the frequency of 922 MHz of the antenna of the present invention;
in the figure: 1-a dielectric substrate; 2-a ground plate; 3-radiation patch; 4-coupled parasitic patches; 5-a feed structure; 6-coaxial cable; 7-an air layer;
21-a folded configuration; 22-rectangular metal strips; 23-the radiating device cavity.
Detailed Description
As shown in the figure, the reader antenna for the low-profile wide-beam circular polarization applied to the RFID comprises a grounding plate 2 with a cavity of a radiation device arranged inside; the radiation device cavity is a rectangular cavity in which a medium substrate 1 is arranged; a radiation patch 3 is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in the shape in the plane view; the polygonal ring and the middle parts of four sides of the rectangular cavity, which are parallel to the four side walls, are provided with concave structures; the four side walls of the rectangular cavity are connected with the initial end of the coupling parasitic patch 4; the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is close to the edge of the radiation welt and extends into the concave structure of the polygonal annular edge of the radiation patch.
The grounding plate is of an all-metal structure; the periphery of the grounding plate is provided with a foldable folding structure 21; the folded structure of the ground plate forms a sidewall of the radiating device cavity when the folded structure is in the upwardly folded configuration.
The upper part of the side wall of the radiation device cavity is provided with a rectangular metal strip 22 used for connecting the starting end of the coupling parasitic patch.
The radiation patch is a patch structure printed on the dielectric substrate; the reader antenna further comprises a feed structure 5 printed at the lower surface of the dielectric substrate.
The top view shape of the feed structure comprises two isosceles triangles of different sizes and perpendicularly intersecting at a vertex.
The feed structure and the radiation patch form a feed coupling structure; the perimeter of the polygonal ring of the radiating patch is close to or equal to the wavelength of the antenna beam; when the length of the polygonal ring is changed, the resonant frequency point of the radiating patch is changed; the feed structure is connected with the radiation patch by a coaxial cable 6; the feed coupling structure forms a phase difference by using a coupling area difference between the feed structure and the radiation patch; the phase difference may form a horizontal current and a vertical current in the antenna to circularly polarize the beam radiated from the antenna.
The coupling parasitic patch and the four concave structures of the radiation patch form a small coupling structure with a capacitor in a four-arrow-shaped structure, and the beam width of the antenna can be enlarged by the small coupling structure with the capacitor.
An air layer 7 is arranged between the dielectric substrate and the cavity bottom of the grounding plate radiation device.
The RFID reader antenna has the advantages that the wave beam frequency band of the reader antenna covers the RFID frequency band, the axial ratio of the wave beam in the maximum radiation direction is less than 3dB, the reader antenna has a circular polarization characteristic, and the wave beam width is wider than the 3dB axial ratio.
The reader antenna is used for mobile terminal equipment.
In this embodiment, the overall size of the antenna is 130mm × 130mm × 8.1mm, and the size of the dielectric substrate is 100mm × 100mm × 0.8 mm.
The dielectric substrate 1 uses FR4 with a relative dielectric constant of 4.4 and tan θ =0.02 as a substrate, and the ground plate uses a copper sheet of 0.3 mm.
The grounding plate is a metal cavity structure formed by folding the folding structure 21 upwards so as to reduce the size of the grounding surface, and then the rectangular strip is folded to be connected with the coupling parasitic patch.
As shown in fig. 5, the radiation patch 3 designed by the present invention is an inwardly recessed ring structure having a circumference of about one wavelength, and its length is adjusted to generate a suitable resonance frequency point.
As shown in fig. 6, four coupling parasitic patches 4 are coupled with four sides of the annular radiation patch 3 to generate capacitance to achieve the effect of reducing the size, and the beam width can be enlarged.
As shown in fig. 7, the feeding structure is designed to be two isosceles triangle structures vertically arranged and coupled with the annular radiation patch to different degrees, so as to generate currents in the horizontal direction and the vertical direction to realize circular polarization of the antenna.
Fig. 8 is a simulation diagram of the 3dB axial ratio beam width of the low-profile wide-axial-ratio circularly polarized reader antenna, and it can be seen from the diagram that the 3dB axial ratio beam width is 190 ° at the lowest among the four principal planes Phi =0 °, Phi = 45 °, Phi =90 °, and Phi = 135 °. The phase difference between the electric fields E theta and E phi is kept around 90 degrees.
FIG. 9 is a diagram showing the simulation result of the reflection coefficient S11 of the circularly polarized reader antenna with low cross-sectional aspect ratio beam width, and it can be seen from the diagram that the simulated-10 dB S11 bandwidth is 881-937 MHz, which can completely cover the whole operating bandwidth of the UHF RFID.
Fig. 10 shows the Axial Ratio (Axial Ratio Value) bandwidth of the low-profile wide Axial Ratio beam width circularly polarized reader antenna, and it can be observed that the simulated AR bandwidth is 907-.
Fig. 11 and 12 show the measured and simulated radiation patterns of the two main planes Phi =0 ° and Phi =90 ° at 922 MHz frequency, respectively, with a simulated gain of 4.6dBi at maximum.
Claims (10)
1. The utility model provides a be applied to RFID's low section broad beam circular polarization reader antenna which characterized in that: the reader antenna comprises a ground plate (2) with a cavity for a radiating element; the radiation device cavity is a rectangular cavity in which a medium substrate (1) is arranged; a radiation patch (3) is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in the shape in the plane view; the polygonal ring and the middle parts of four sides of the rectangular cavity, which are parallel to the four side walls, are provided with concave structures; the four side walls of the rectangular cavity are connected with the initial end of the coupling parasitic patch (4); the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is close to the edge of the radiation welt and extends into the concave structure of the polygonal annular edge of the radiation patch.
2. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 1, wherein: the grounding plate is of an all-metal structure; the periphery of the grounding plate is provided with a foldable folding structure (21); the folded structure of the ground plate forms a sidewall of the radiating device cavity when the folded structure is in the upwardly folded configuration.
3. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 2, wherein: and a rectangular metal strip (22) used for connecting the starting end of the coupling parasitic patch is arranged at the upper part of the side wall of the radiation device cavity.
4. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 2, wherein: the radiation patch is a patch structure printed on the dielectric substrate; the reader antenna further comprises a feed structure (5) printed at the lower surface of the dielectric substrate.
5. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 4, wherein: the top view shape of the feed structure comprises two isosceles triangles of different sizes and perpendicularly intersecting at a vertex.
6. The low-profile wide-beam circularly polarized reader antenna applied to the RFID according to claim 5, wherein: the feed structure and the radiation patch form a feed coupling structure; the perimeter of the polygonal ring of the radiating patch is close to or equal to the wavelength of the antenna beam; when the length of the polygonal ring is changed, the resonant frequency point of the radiating patch is changed; the feed structure is connected with the radiation patch by a coaxial cable (6); the feed coupling structure forms a phase difference by using a coupling area difference between the feed structure and the radiation patch; the phase difference may form a horizontal current and a vertical current in the antenna to circularly polarize the beam radiated from the antenna.
7. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 1, wherein: the coupling parasitic patch and the four concave structures of the radiation patch form a small coupling structure with a capacitor in a four-arrow-shaped structure, and the beam width of the antenna can be enlarged by the small coupling structure with the capacitor.
8. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 1, wherein: an air layer (7) is arranged between the dielectric substrate and the cavity bottom of the grounding plate radiation device.
9. The low-profile wide-beam circularly polarized reader antenna applied to the RFID according to claim 5, wherein: the RFID reader antenna has the advantages that the wave beam frequency band of the reader antenna covers the RFID frequency band, the axial ratio of the wave beam in the maximum radiation direction is less than 3dB, the reader antenna has a circular polarization characteristic, and the wave beam width is wider than the 3dB axial ratio.
10. The low-profile wide-beam circularly polarized reader antenna applied to the RFID as claimed in claim 1, wherein: the reader antenna is used for mobile terminal equipment.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011339248.2A CN112310609B (en) | 2020-11-25 | 2020-11-25 | Low-profile wide-beam circularly polarized reader antenna applied to RFID |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011339248.2A CN112310609B (en) | 2020-11-25 | 2020-11-25 | Low-profile wide-beam circularly polarized reader antenna applied to RFID |
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| CN112310609A true CN112310609A (en) | 2021-02-02 |
| CN112310609B CN112310609B (en) | 2024-07-05 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112968272A (en) * | 2021-02-03 | 2021-06-15 | 重庆邮电大学 | Wide-bandwidth beam low-profile circularly polarized antenna |
| CN114024124A (en) * | 2022-01-05 | 2022-02-08 | 上海英内物联网科技股份有限公司 | Miniaturized circularly polarized reader antenna capable of reading in near-field and far-field manners |
| US20220158357A1 (en) * | 2020-11-19 | 2022-05-19 | Samsung Electro-Mechanics Co., Ltd | Antenna apparatus |
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| CN110571516A (en) * | 2019-10-16 | 2019-12-13 | 福州大学 | Z-shaped coupling feed small-sized directional circularly polarized RFID reader antenna |
| CN213340704U (en) * | 2020-11-25 | 2021-06-01 | 福州大学 | Low-profile wide-beam circularly polarized reader antenna applied to RFID |
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2020
- 2020-11-25 CN CN202011339248.2A patent/CN112310609B/en active Active
Patent Citations (8)
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| CN101038618A (en) * | 2006-12-01 | 2007-09-19 | 华南理工大学 | Intelligent antenna system of RFID reading machine |
| KR101470914B1 (en) * | 2013-06-25 | 2014-12-10 | (주)알판트 | Parasitic element coupling feeder rfid circular polarized antenna |
| CN104241825A (en) * | 2014-09-12 | 2014-12-24 | 华南理工大学 | Universal ultrahigh-frequency circularly polarized antenna for reader |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220158357A1 (en) * | 2020-11-19 | 2022-05-19 | Samsung Electro-Mechanics Co., Ltd | Antenna apparatus |
| CN112968272A (en) * | 2021-02-03 | 2021-06-15 | 重庆邮电大学 | Wide-bandwidth beam low-profile circularly polarized antenna |
| CN114024124A (en) * | 2022-01-05 | 2022-02-08 | 上海英内物联网科技股份有限公司 | Miniaturized circularly polarized reader antenna capable of reading in near-field and far-field manners |
| CN114024124B (en) * | 2022-01-05 | 2022-06-24 | 上海英内物联网科技股份有限公司 | Miniaturized circularly polarized reader antenna capable of achieving near-field and far-field reading |
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| CN112310609B (en) | 2024-07-05 |
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