CN112310609B - 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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- CN112310609B CN112310609B CN202011339248.2A CN202011339248A CN112310609B CN 112310609 B CN112310609 B CN 112310609B CN 202011339248 A CN202011339248 A CN 202011339248A CN 112310609 B CN112310609 B CN 112310609B
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- 230000005855 radiation Effects 0.000 claims abstract description 69
- 238000010168 coupling process Methods 0.000 claims abstract description 34
- 238000005859 coupling reaction Methods 0.000 claims abstract description 34
- 230000008878 coupling Effects 0.000 claims abstract description 33
- 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 8
- 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 10
- 238000000034 method Methods 0.000 description 4
- 238000004088 simulation 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
- 238000013068 supply chain management Methods 0.000 description 1
Classifications
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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
-
- 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
-
- 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
-
- 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, which comprises a grounding plate (2) with a built-in radiation device cavity; the radiation device cavity is a rectangular cavity provided with a dielectric substrate (1) inside; a radiation patch (3) is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in top view; the middle parts of four sides of the polygonal ring, which are parallel to the four side walls of the rectangular cavity, are provided with concave structures; four side walls of the rectangular cavity are connected with the starting ends of the coupling parasitic patches (4); the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is closely adjacent to the edge of the radiation welt and extends into the concave structure of the polygonal ring edge of the radiation patch; the invention can cover RFID frequency band, has low profile and directional radiation, has the axial ratio of less than 3dB in the maximum radiation direction, has circular polarization and 3dB axial ratio and wide 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 fields such as logistics, supply chain management, asset tracking, and vehicle positioning. The use of different radio frequencies and technologies in a wide variety of ultra-high frequency passive radio frequency identification systems has received considerable attention due to their 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. It is known that circular polarized radiation can be obtained by exciting two orthogonal electric field components of equal amplitude and 90 degrees phase difference, and the currently common methods mainly include a multi-feed method and a single-feed method. For an RFID reader antenna, the wider the beam width, the wider the range in which the antenna can effectively identify an electronic tag. Therefore, in designing a reader antenna, it is necessary to pay attention to the beam width of the antenna or to expand the range covering the electronic tag by beam scanning. In addition to the pursuit of performance and quality improvement, RFID antennas are being developed toward broadband and multi-frequency applications, and in particular fabrication technologies are being developed toward miniaturization, planarization, and ease of fabrication. Therefore, the research on the miniaturized loop antenna has wide application prospect in an 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 an axial ratio of less than 3dB in the maximum radiation direction, has circular polarization and 3dB axial ratio and wide 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 polarized reader antenna for RFID applications, the reader antenna comprising a ground plate (2) with a radiating element cavity built-in; the radiation device cavity is a rectangular cavity provided with a dielectric substrate (1) inside; a radiation patch (3) is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in top view; the middle parts of four sides of the polygonal ring, which are parallel to the four side walls of the rectangular cavity, are provided with concave structures; four side walls of the rectangular cavity are connected with the starting ends of the coupling parasitic patches (4); the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is closely adjacent to the edge of the radiation welt and is inserted into the concave structure of the polygonal ring 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 structure (21); the folded structure of the ground plate forms a side wall of the cavity of the radiating element when in an upwardly folded configuration.
The upper part of the side wall of the cavity of the radiation device is provided with a rectangular metal strip (22) for connecting the initial 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 intersecting perpendicularly at the apex.
The feed structure and the radiation patch form a feed coupling structure; the perimeter of the polygonal ring of the radiation patch is close to or equal to the wavelength of the antenna beam; when the length of the polygonal ring is changed, the resonance frequency point of the radiation patch is also changed; the feed structure is connected with the radiation patch by a coaxial cable (6); the feed coupling structure forms a phase difference by the coupling area difference between the feed structure and the radiation patch; the phase difference may form horizontal and vertical currents within the antenna to circularly polarize the antenna radiation beam.
The coupling parasitic patch forms a small coupling structure with a capacitor by four arrow-shaped structures and four concave structures of the radiation patch, and the small coupling structure with the capacitor can enlarge the beam width of the antenna.
An air layer (7) is arranged between the dielectric substrate and the cavity bottom of the grounding plate radiation device cavity.
The beam frequency band of the reader antenna covers the RFID frequency band, the axial ratio of the beam in the maximum radiation direction is smaller than 3dB, the reader antenna has circular polarization characteristics, and the 3dB axial ratio is wider than the beam width.
The reader antenna is used for the mobile terminal equipment.
Compared with the prior art, the invention has the following advantages: the antenna has a simple structure and is easy to process, and directional radiation is realized so that the gain of the antenna in the maximum radiation direction is high and circular polarization exists in the direction.
Drawings
The invention is described in further detail below with reference to the attached drawings and detailed description:
fig. 1 is a schematic 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 according to the present invention;
FIG. 5 is a schematic diagram of the area of the antenna of the present invention where the patch is radiating in front view;
FIG. 6 is a schematic diagram of an area of an arrow-shaped coupling parasitic patch in front view of an antenna according to the present invention;
fig. 7 is a schematic diagram of an area of an isosceles triangle feed structure in front view of an antenna according to the present invention;
FIG. 8 is a schematic diagram of a 3dB axial ratio beam width simulation of an antenna according to the present invention;
FIG. 9 is a schematic diagram of an antenna S11 according to the present invention;
FIG. 10 is a schematic diagram of an antenna axis ratio simulation according to the present invention;
fig. 11 is a schematic diagram of radiation direction measured and simulated on a phi=0° plane at a frequency of an antenna 922 MHz according to the present invention;
Fig. 12 is a schematic diagram of radiation directions actually measured and simulated in a phi=90° plane at a frequency of an antenna 922 MHz according to the present invention;
in the figure: 1-a dielectric substrate; 2-a ground plate; 3-radiating patches; 4-coupling parasitic patches; a 5-feed structure; 6-coaxial cable; 7-air layer;
a 21-fold structure; 22-rectangular metal strips; 23-radiating device cavity.
Detailed Description
As shown in the figure, a low-profile wide-beam circularly polarized reader antenna for RFID applications, the reader antenna comprising a ground plate 2 with a radiating element cavity built-in; the radiation device cavity is a rectangular cavity provided with a dielectric substrate 1 inside; the upper surface of the dielectric substrate is provided with a radiation patch 3; the radiation patch is polygonal in top view; the middle parts of four sides of the polygonal ring, which are parallel to the four side walls of the rectangular cavity, are provided with concave structures; four side walls of the rectangular cavity are connected with the starting ends of the coupling parasitic patches 4; the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is closely adjacent to the edge of the radiation welt and is inserted into the concave structure of the polygonal ring 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 structure 21; the folded structure of the ground plate forms a side wall of the cavity of the radiating element when in an upwardly folded configuration.
The upper part of the side wall of the cavity of the radiation device is provided with a rectangular metal strip 22 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 intersecting perpendicularly at the apex.
The feed structure and the radiation patch form a feed coupling structure; the perimeter of the polygonal ring of the radiation patch is close to or equal to the wavelength of the antenna beam; when the length of the polygonal ring is changed, the resonance frequency point of the radiation patch is also changed; the feed structure is connected with the radiating patch by a coaxial cable 6; the feed coupling structure forms a phase difference by the coupling area difference between the feed structure and the radiation patch; the phase difference may form horizontal and vertical currents within the antenna to circularly polarize the antenna radiation beam.
The coupling parasitic patch forms a small coupling structure with a capacitor by four arrow-shaped structures and four concave structures of the radiation patch, and the small coupling structure with the capacitor can enlarge the beam width of the antenna.
An air layer 7 is arranged between the dielectric substrate and the cavity bottom of the grounding plate radiation device cavity.
The beam frequency band of the reader antenna covers the RFID frequency band, the axial ratio of the beam in the maximum radiation direction is smaller than 3dB, the reader antenna has circular polarization characteristics, and the 3dB axial ratio is wider than the beam width.
The reader antenna is used for the mobile terminal equipment.
In this embodiment, the overall dimensions of the antenna are 130mm by 8.1mm, and the dimensions of the dielectric substrate are 100mm by 0.8mm.
The dielectric substrate 1 was an FR4 substrate having a relative dielectric constant of 4.4 and tan θ=0.02, and the ground plate was a copper sheet of 0.3 mm.
The ground plate is formed by folding up the folded structure 21 to form a metal cavity structure to reduce the size of the ground plate, and then folding the rectangular strip to connect with the coupling parasitic patch.
As shown in fig. 5, the radiating patch 3 of the present invention is an inwardly recessed ring structure having a circumference of about one wavelength, and a suitable resonance frequency point is generated by adjusting the length thereof.
As shown in fig. 6, four coupling parasitic patches 4 are coupled with four sides of the loop-shaped radiation patch 3 to generate capacitance for achieving 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 a coupling degree of two isosceles triangle structures placed vertically and the annular radiating patch is different in order to generate currents in the horizontal direction and the vertical direction to realize circular polarization of the antenna.
Fig. 8 is a 3dB axial ratio beam width simulation of a low profile wide axial ratio beam width circularly polarized reader antenna, from which it can be seen that the 3dB axial ratio beam width at four principal planes phi=0 °, phi=45 °, phi=90°, and phi=135° is at least 190 °. The phase difference between the electric fields E theta and E phi is also kept at about 90 deg.
Fig. 9 is a diagram showing the simulation result of the reflection coefficient S11 of the low-profile wide-axis-ratio beam width circularly polarized reader antenna, and it can be seen from the diagram that the simulated bandwidth of-10 dB |s11| is 881-937 MHz, and the whole working bandwidth of the uhf rfid can be completely covered.
Fig. 10 shows the axial ratio (Axial Ratio Value) bandwidth of a low profile wide axial ratio beamwidth circularly polarized reader antenna, with simulated AR bandwidths of 907-923 MHz observed.
Fig. 11 and 12 show two main plane measured and simulated radiation patterns, phi=0° and phi=90° at 922 MHz frequencies, respectively, with a simulated gain of at most 4.6dBi.
Claims (5)
1. A low profile wide beam circularly polarized reader antenna for RFID applications, characterized by: the reader antenna comprises a grounding plate (2) with a radiation device cavity inside; the radiation device cavity is a rectangular cavity provided with a dielectric substrate (1) inside; a radiation patch (3) is arranged on the upper surface of the dielectric substrate; the radiation patch is polygonal in top view; the middle parts of four sides of the polygonal ring, which are parallel to the four side walls of the rectangular cavity, are provided with concave structures; four side walls of the rectangular cavity are connected with the starting ends of the coupling parasitic patches (4); the tail end of the coupling parasitic patch is an arrow-shaped structure pointing to the radiation patch; the arrow-shaped structure is closely adjacent to the edge of the radiation welt and extends into the concave structure of the polygonal ring 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 structure (21); when the folded structure of the ground plate is in an upwardly folded configuration, the folded structure forms a sidewall of the radiating element 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 which are different in size and vertically intersected at the vertex;
The feed structure and the radiation patch form a feed coupling structure; the perimeter of the polygonal ring of the radiation patch is close to or equal to the wavelength of the antenna beam; when the length of the polygonal ring is changed, the resonance frequency point of the radiation patch is also changed; the feed structure is connected with the radiation patch by a coaxial cable (6); the feed coupling structure forms a phase difference by the coupling area difference between the feed structure and the radiation patch; the phase difference may form a horizontal current and a vertical current within the antenna to circularly polarize the antenna radiation beam;
an air layer (7) is arranged between the dielectric substrate and the cavity bottom of the grounding plate radiation device cavity.
2. A low profile wide beam circularly polarized reader antenna for use in RFID applications as in claim 1, wherein: the upper part of the side wall of the cavity of the radiation device is provided with a rectangular metal strip (22) for connecting the initial end of the coupling parasitic patch.
3. A low profile wide beam circularly polarized reader antenna for use in RFID applications as in claim 1, wherein: the coupling parasitic patch forms a small coupling structure with a capacitor by four arrow-shaped structures and four concave structures of the radiation patch, and the small coupling structure with the capacitor can enlarge the beam width of the antenna.
4. A low profile wide beam circularly polarized reader antenna for use in RFID applications as in claim 1, wherein: the beam frequency band of the reader antenna covers the RFID frequency band, the axial ratio of the beam in the maximum radiation direction is smaller than 3dB, the reader antenna has circular polarization characteristics, and the 3dB axial ratio is wider than the beam width.
5. A low profile wide beam circularly polarized reader antenna for use in RFID applications as in claim 1, wherein: the reader antenna is used for the mobile terminal equipment.
Priority Applications (1)
| 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 CN112310609A (en) | 2021-02-02 |
| CN112310609B true CN112310609B (en) | 2024-07-05 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20220068557A (en) * | 2020-11-19 | 2022-05-26 | 삼성전기주식회사 | Antenna apparatus |
| CN112968272B (en) * | 2021-02-03 | 2023-03-24 | 重庆邮电大学 | Wide-bandwidth beam low-profile circularly polarized antenna |
| KR20230053423A (en) * | 2021-10-14 | 2023-04-21 | 동우 화인켐 주식회사 | Antrnna package and display device including the same |
| 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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| Publication number | Priority date | Publication date | Assignee | Title |
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| 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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| CN101038618B (en) * | 2006-12-01 | 2010-04-07 | 华南理工大学 | An RFID reader smart antenna system |
| 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 |
| CN108306106B (en) * | 2018-01-29 | 2023-06-27 | 福州大学 | Miniaturized rectangular patch short-circuit loaded satellite navigation loop antenna and terminal |
| CN208299032U (en) * | 2018-06-04 | 2018-12-28 | 福州大学 | A kind of miniaturization directed radiation MIMO reader antenna for RFID |
| CN109149092B (en) * | 2018-07-27 | 2023-12-29 | 华南师范大学 | Compact single-feed broadband circularly polarized RFID reader antenna |
| CN110571516B (en) * | 2019-10-16 | 2024-02-06 | 福州大学 | Z-shaped coupling feed small-sized directional circularly polarized RFID reader antenna |
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| 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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