CN113314829A - Radio frequency identification ultrahigh frequency band tag antenna applied to metal environment - Google Patents
Radio frequency identification ultrahigh frequency band tag antenna applied to metal environment Download PDFInfo
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- CN113314829A CN113314829A CN202110677043.3A CN202110677043A CN113314829A CN 113314829 A CN113314829 A CN 113314829A CN 202110677043 A CN202110677043 A CN 202110677043A CN 113314829 A CN113314829 A CN 113314829A
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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
- H01Q1/2225—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 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
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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
- H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/52—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
- H01Q9/045—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular feeding means
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Abstract
The invention relates to a radio frequency identification ultrahigh frequency band tag antenna used in a metal environment, belonging to the technical field of radio frequency identification electronic tags. The radio frequency identification tag antenna comprises a radiation patch, a tag chip, a dielectric substrate and a metal bottom plate, wherein the radiation patch comprises a bent T-shaped open stub feed structure, an H-shaped groove and a symmetrical rectangular gap, and the chip is positioned on the open stub. During design, the metal bottom plate is used as a part of the tag antenna, so that the tag antenna has metal resistance, and through simulation and experimental tests, the actual reading distance of the tag antenna in a working frequency band is over 3.48m and the maximum recognition distance reaches 6.24m under a metal environment and exceeds the common metal resistance tag performance; and the resonant frequency, the gain and the like of the tag antenna are less influenced by metal. The-3 dB bandwidth of the tag antenna is 863 MHz-940 MHz, the center frequency is 915MHz, the antenna is directly printed on a single-layer substrate, and a grounding layer or a short-circuit pin is not arranged, so that the manufacturing cost can be reduced.
Description
Technical Field
The invention belongs to the technical field of radio frequency identification, relates to a radio frequency identification electronic tag, and particularly relates to an anti-metal tag antenna working in an ultrahigh frequency band.
Background
Radio Frequency Identification (RFID) technology is widely used in a plurality of fields and industries such as logistics management, transportation, and medical care because of its long reading distance. In most of the application scenarios described above, the RFID tag antenna inevitably contacts the metal object. However, when the common passive uhf tag having a dipole-like antenna is applied to a metal surface, the impedance matching, the radiation efficiency, and the radiation pattern of the tag are changed, so that the tag performance is deteriorated, and even the tag cannot be effectively read.
For a common passive ultrahigh frequency tag, when the tag is attached to a metal surface, the impedance matching, the radiation efficiency and the directivity of a tag antenna are changed. The read distance of the tag is rapidly reduced and even difficult to read. Therefore, it is necessary to specially treat it or to use special labels so that it can be applied to metal surfaces.
There are generally three solutions: 1. the wave-absorbing material is adhered to the surface of the metal to overcome the reflection effect of the metal. 2. The label is raised by a certain height, so that the influence of the boundary condition of metal is reduced. 3. And a special anti-metal tag antenna design method is adopted.
The first two methods can restore a certain reading distance of a common label to a certain extent, but the method is not an optimal solution, and either the performance is limited or the thickness of the label cannot meet the requirements of practical application. For this purpose, specially designed antennas may be used as antennas for the tag, overcoming the effect of the metal surface. Generally, a metal-resistant label is a special label which is specially designed and can be applied to the surface of a metal object.
Disclosure of Invention
The invention provides a Radio Frequency Identification (RFID) ultrahigh frequency band tag antenna applied to a metal environment, aiming at solving the problem that the performance of the tag antenna is deteriorated in the metal environment and overcoming the problems of large size and difficult processing process of the existing anti-metal tag.
A radio frequency identification ultrahigh frequency band tag antenna applied to a metal environment comprises a radiation patch 4, a tag chip 2 and a dielectric substrate 8, wherein the radiation patch 4 is fixedly arranged on one side surface of the dielectric substrate 8;
one side edge of the radiation patch 4 is parallel to one side edge of the medium substrate 8, the corresponding other side edge is positioned in the middle of the medium substrate 8, the middle of the other side edge is provided with an inward-concave U-shaped groove 7, the bottom in the U-shaped groove 7 is connected with one end of a linear radiation arm 6, the label chip 2 is arranged at the joint of the radiation arm 6 and the radiation patch 4, the other end of the radiation arm 6 is connected with the bottom end of a vertical arm of the T-shaped radiation arm 1, and a horizontal arm of the T-shaped radiation arm 1 is parallel to one side edge of the other pair of edges of the medium substrate 8; the T-shaped radiating arm 1 and the radiating arm 6 form an open-circuit stub feeding structure;
the radiation patch 4 is provided with an H-shaped groove 5, and a middle connecting line in the H-shaped groove 5 is in a straight line with the radiation arm 6;
a pair of edge lines of the radiation patch 4 between the U-shaped groove 7 and the H-shaped groove 5 are respectively provided with an inward concave rectangular seam 3;
a metal bottom plate 9 is arranged on the bottom surface of the dielectric substrate 8;
the-3 dB bandwidth of the radio frequency identification tag antenna is 863 MHz-940 MHz, the center frequency is 915MHz, and the radio frequency identification tag antenna can be normally used in a metal environment or a nonmetal environment.
The specific technical parameters of the label are as follows:
the material of the radiation patch 4 and the material of the metal base plate 9 are both copper, and the thickness of the radiation patch 4 and the thickness of the metal base plate 9 are both 0.2 mm; the medium substrate 8 is made of FR4 and has a thickness of 3.0 mm.
The H-shaped groove 5 is formed by etching through a metal etching process, three rectangular grooves form the H-shaped groove, the size W8 multiplied by L5 of the two symmetrical rectangular grooves is 32mm multiplied by 6mm, and the size W9 multiplied by L6 of the long rectangular groove connecting the two symmetrical rectangular grooves is 2mm multiplied by 17 mm.
The T-shaped radiating arm 1 is composed of two rectangular patches, and the size of the T-shaped radiating arm is as follows: the rectangular patch size W3+ W6 × W6 connected to the elongated radiation arm 6 is 17mm × 2mm, and the other rectangular patch size W2 × L8 is 2mm × 8 mm.
The dielectric substrate 8 and the metal bottom plate 9 have the same size W1 × L1 of 40mm × 89 mm.
Compared with the prior art, the invention has the beneficial technical effects in the following aspects:
1. the tag antenna has a simple structure and a small volume, and adopts a bending technology on the basis of a common open-circuit stub microstrip antenna to change the original strip shape of the open-circuit stub into the existing T-shaped bent shape, so that the volume of the antenna is effectively reduced, and meanwhile, an H-shaped groove is formed on a radiation surface by adopting an etching technology, so that the bandwidth of the antenna is increased, and the central frequency of the tag antenna is conveniently adjusted.
2. The tag antenna adopts an embedded feeding mode, the open stub is embedded in the U-shaped groove 7 of the radiation patch, the self impedance of the tag antenna can be changed by adjusting the depth and the width of the U-shaped groove 7, meanwhile, the self impedance of the tag antenna can be changed by changing the length and the width of the feeding part of the open stub, the total impedance of the antenna is equal to the impedance of the radiation patch plus the impedance of the open stub, and the reactance of the open stub is adjusted within a range of- ∞ to + ∞, so that the reactance of the input impedance of the antenna can be increased or reduced in a larger range on the basis of the impedance of the radiation microstrip line, and the impedance matching of the tag antenna and a tag chip can be realized.
3. The bottom of the anti-metal label antenna is provided with the metal bottom plate, the length and the width of the metal bottom plate are equal to those of the dielectric substrate, and the metal bottom plate is used as a part of the antenna, so that the antenna has anti-metal performance at the beginning of antenna design, and the antenna can be normally used in a non-metal environment.
4. Tests show that the tag antenna has good performance in a metal environment, the tag has a far identification distance in a free space, the-3 dB bandwidth of the antenna is 863 MHz-940 MHz, and the antenna basically covers the global frequency range 860 MHz-960 MHz set by EPC C1G 2. And the return loss at 915MHz was-28.58 dBi, exceeding the typical antenna performance. The anti-metal tag antenna designed by adopting the microstrip antenna or the planar inverted-F antenna has narrow bandwidth, and the-3 dB bandwidth is about 15-20 MHz. Some improved anti-metal tag antennas have-3 dB bandwidth which can reach about 57MHz, while the bandwidth of the antenna of the invention reaches 77 MHz. In addition, the reading distance of the tag antennas actually applied to the metal environment is generally 4-5.5 m, and the maximum identification distance of the tag antennas in the metal environment reaches 6.24m and exceeds that of common anti-metal tags.
5. The tag antenna has small volume and a planar structure, so that a printed circuit board can be used as a substrate to form a PCB tag, which not only realizes miniaturization, but also has the advantages of easy debugging and batch production of the PCB tag.
Drawings
Fig. 1 is a three-dimensional perspective view of the anti-metal tag antenna of the present invention.
Fig. 2 is a top view structural diagram of the anti-metal tag antenna of the present invention.
Fig. 3 is a length dimension chart of the radiation patch of the anti-metal tag antenna of the present invention.
Fig. 4 is a drawing illustrating the width dimension of the radiation patch of the metal-tag-resistant antenna according to the present invention.
FIG. 5 is a power reflection function diagram (S) of the metal-tag-resistant antenna of the present invention under a metal environment and a non-metal environment11）。
FIG. 6 is a diagram of the power reflection function of the public tag antenna ALN-9640 under metal environment and nonmetal environment (S)11）。
Fig. 7 is a reading distance diagram of the anti-metal tag antenna of the present invention under metal and non-metal environments.
Fig. 8 is a reading distance diagram of the public tag antenna ALN9640 in a metallic environment and a non-metallic environment.
Fig. 9 is a three-dimensional gain diagram of the anti-metal tag antenna of the present invention.
Number in fig. 1-2: t-shaped radiation arm 1, radiation arm 6, label chip 2, rectangular slot 3, radiation patch 4, H-shaped slot 5, dielectric substrate 8 and metal bottom plate 9.
Detailed Description
The present invention will be described in further detail by way of examples with reference to the accompanying drawings.
Example 1
With reference to fig. 1 and 2, an rfid tag antenna applied to a metal environment includes a tag chip 2, a radiation patch 4, a dielectric substrate 8, and a metal base plate 9. The radiation patch 4 is fixedly attached to the top surface of the medium substrate 8, and the metal bottom plate 9 is fixedly attached to the bottom surface of the medium substrate 8. The material of the radiation patch 4 and the material of the metal base plate 9 are both copper, and the thickness of the radiation patch 4 and the thickness of the metal base plate 9 are both 0.2 mm; the dielectric substrate 8 was made of FR4 and had a thickness of 3.0 mm. As can be seen from fig. 3 and 4, the dielectric substrate 8 and the metal base plate 9 have the same dimensions W1 × L1 of 40mm × 89 mm.
With reference to fig. 1 and 2, one side of the radiation patch 4 is parallel to one side of the dielectric substrate 8, the corresponding other side is located in the middle of the dielectric substrate 8, an inwardly concave U-shaped groove 7 is formed in the middle of the other side, the bottom of the U-shaped groove 7 is connected to one end of a linear radiation arm 6, the tag chip 2 is installed at the connection position of the radiation arm 6 and the radiation patch 4, the other end of the radiation arm 6 is connected to the bottom end of a vertical arm of the T-shaped radiation arm 1, and a horizontal arm of the T-shaped radiation arm 1 is parallel to the long radiation arm 6; the T-shaped radiating arm 1 and the radiating arm 6 constitute an open stub feed structure. With reference to fig. 3 and 4, the T-shaped radiating arm 1 is composed of two rectangular patches, whose dimensions are: the rectangular patch size W3+ W6 × W6 connected to the elongated radiation arm 6 is 17mm × 2mm, and the other rectangular patch size W2 × L8 is 2mm × 8 mm.
With reference to fig. 1 and 2, the radiation patch 4 is provided with an H-shaped groove 5 by using a slotting technology, and a middle connecting line in the H-shaped groove 5 is in a straight line with the radiation arm 6; a pair of edge lines of the radiation patch 4 between the U-shaped groove 7 and the H-shaped groove 5 are respectively provided with an inward concave rectangular seam 3. With reference to fig. 2-4, the H-shaped groove 5 is formed by etching through a metal etching process, and is formed by three rectangular grooves, wherein the two symmetrical rectangular grooves have a dimension W8 × L5 of 32mm × 6mm, and the two symmetrical rectangular grooves have a dimension W9 × L6 of 2mm × 17 mm.
The impedance and the resonant frequency of the tag antenna are adjusted by adjusting the size parameters of the H-shaped groove 5 and the T-shaped radiating arm 1, the tag antenna is tested in the environment with or without metal, the test result is shown in FIG. 5, the central resonant frequency in the environment without metal is 910MHz, the return loss is-44.71 dB, and the operating bandwidth of 64MHz is available, the central resonant frequency in the environment with metal is 913MHz, the return loss is-33.94 dB, the tag is not greatly affected by the visible metal environment, and the tag can be normally used.
In order to highlight the metal resistance of the radio frequency identification ultrahigh frequency band tag antenna, a performance comparison experiment with a public version tag ALN-9640 is carried out, and as can be clearly seen from an experiment result shown in FIG. 6, when the ALN-9640 tag antenna is attached to a metal surface, the central frequency offset is serious, and the working bandwidth is basically zero.
As shown in fig. 7, a distance graph is read in a metal environment and a free space under an ideal matching state of the radio frequency identification ultrahigh frequency band tag antenna, calculation is performed by using a formula, and a calculation simulation result shows that the anti-metal tag has a good identification distance in both a metal environment and a non-metal environment.
In order to highlight the metal resistance of the radio frequency identification ultrahigh frequency band tag antenna, a performance comparison experiment with a public version tag ALN-9640 is carried out, and as shown in an experiment result shown in fig. 8, it is obvious that the ALN-9640 tag antenna is not normally used because the reading distance is basically 0 when the ALN-9640 tag antenna is attached to a metal surface.
As shown in fig. 9, which is a three-dimensional directional gain diagram of the rfid tag antenna of the present invention, the maximum gain obtained by the antenna at 915MHz operating frequency is-0.86 dB, which meets the design requirement.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and the inventive concept within the scope of the present invention disclosed by the present invention.
Claims (5)
1. The utility model provides a be applied to metallic environment's radio frequency identification UHF frequency channel label antenna, includes radiation paster (4), label chip (2) and dielectric substrate (8), and radiation paster (4) are fixed to be located on a side of dielectric substrate (8), its characterized in that:
one side of the radiation patch (4) is parallel to one side of the dielectric substrate (8), the corresponding other side is located in the middle of the dielectric substrate (8), an inward concave U-shaped groove (7) is formed in the middle of the other side, the bottom of the U-shaped groove (7) is connected with one end of a linear radiation arm (6), the label chip (2) is arranged at the joint of the radiation arm (6) and the radiation patch (4), the other end of the radiation arm (6) is connected with the bottom end of a vertical arm of the T-shaped radiation arm (1), and a horizontal arm of the T-shaped radiation arm (1) is parallel to one side of the other side of the dielectric substrate (8); the T-shaped radiating arm (1) and the radiating arm (6) form an open-circuit stub feed structure;
an H-shaped groove (5) is formed in the radiation patch (4), and a middle connecting line in the H-shaped groove (5) is in a straight line with the radiation arm (6);
the symmetrical edge lines of the radiation patches (4) between the U-shaped groove (7) and the H-shaped groove (5) are respectively provided with an inward concave rectangular seam (3);
a metal bottom plate (9) is arranged on the bottom surface of the dielectric substrate (8);
the-3 dB bandwidth of the radio frequency identification tag antenna is 863 MHz-940 MHz, the center frequency is 915MHz, and the radio frequency identification tag antenna can be normally used in a metal environment or a nonmetal environment.
2. The radio frequency identification UHF tag antenna applied to metal environment as claimed in claim 1, wherein: the material of the radiation patch (4) and the material of the metal bottom plate (9) are both copper, and the thickness of the radiation patch (4) and the thickness of the metal bottom plate (9) are both 0.2 mm; the medium substrate (8) is made of FR4 and has a thickness of 3.0 mm.
3. The radio frequency identification UHF tag antenna applied to metal environment as claimed in claim 1, wherein: the H-shaped groove (5) is formed by etching through a metal etching process, the H-shaped groove is formed by three rectangular grooves, the size W8 multiplied by L5 of the two symmetrical rectangular grooves is 32mm multiplied by 6mm, and the size W9 multiplied by L6 of the long rectangular groove connecting the two symmetrical rectangular grooves is 2mm multiplied by 17 mm.
4. The radio frequency identification UHF tag antenna applied to metal environment as claimed in claim 1, wherein: the T-shaped radiating arm (1) is composed of two rectangular patches, and the size of the T-shaped radiating arm is as follows: the rectangular patch size (W3 + W6) × W6 connected to the elongate radiating arm (6) is 17mm × 2mm, and the other rectangular patch size W2 × L8 is 2mm × 8 mm.
5. The radio frequency identification UHF tag antenna applied to metal environment as claimed in claim 1, wherein: the dielectric substrate (8) and the metal bottom plate (9) have the same size W1 multiplied by L1 which is 40mm multiplied by 89 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110677043.3A CN113314829A (en) | 2021-06-18 | 2021-06-18 | Radio frequency identification ultrahigh frequency band tag antenna applied to metal environment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110677043.3A CN113314829A (en) | 2021-06-18 | 2021-06-18 | Radio frequency identification ultrahigh frequency band tag antenna applied to metal environment |
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| CN113314829A true CN113314829A (en) | 2021-08-27 |
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| CN202110677043.3A Pending CN113314829A (en) | 2021-06-18 | 2021-06-18 | Radio frequency identification ultrahigh frequency band tag antenna applied to metal environment |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080231458A1 (en) * | 2007-03-23 | 2008-09-25 | Zih Corp. | Rfid tag with reduced detuning characteristics |
| KR20110123632A (en) * | 2010-05-07 | 2011-11-15 | 재단법인 광양만권 유아이티연구소 | Broadband rfid metal tag antenna using uhf band and attachable to metal surface |
| CN105305040A (en) * | 2015-09-25 | 2016-02-03 | 西安电子科技大学 | Antenna used for anti-metal tag and antenna signal transmitting and receiving method |
| CN109713427A (en) * | 2018-11-29 | 2019-05-03 | 河北工业大学 | A kind of ultrathin flexible UHF RFID anti-metal tag antenna |
| CN112038750A (en) * | 2020-09-04 | 2020-12-04 | 合肥工业大学 | Anti-metal tag antenna applied to UHF frequency band |
-
2021
- 2021-06-18 CN CN202110677043.3A patent/CN113314829A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080231458A1 (en) * | 2007-03-23 | 2008-09-25 | Zih Corp. | Rfid tag with reduced detuning characteristics |
| KR20110123632A (en) * | 2010-05-07 | 2011-11-15 | 재단법인 광양만권 유아이티연구소 | Broadband rfid metal tag antenna using uhf band and attachable to metal surface |
| CN105305040A (en) * | 2015-09-25 | 2016-02-03 | 西安电子科技大学 | Antenna used for anti-metal tag and antenna signal transmitting and receiving method |
| CN109713427A (en) * | 2018-11-29 | 2019-05-03 | 河北工业大学 | A kind of ultrathin flexible UHF RFID anti-metal tag antenna |
| CN112038750A (en) * | 2020-09-04 | 2020-12-04 | 合肥工业大学 | Anti-metal tag antenna applied to UHF frequency band |
Non-Patent Citations (1)
| Title |
|---|
| YEJUN HE: ""A new UHF anti-metal RFID tag antenna design with open-circuited stub feed"", 《2013 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC)》 * |
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Application publication date: 20210827 |