CN113937483A - Low-profile anti-metal tag antenna applied to ultrahigh frequency band - Google Patents
Low-profile anti-metal tag antenna applied to ultrahigh frequency band Download PDFInfo
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- CN113937483A CN113937483A CN202111199421.8A CN202111199421A CN113937483A CN 113937483 A CN113937483 A CN 113937483A CN 202111199421 A CN202111199421 A CN 202111199421A CN 113937483 A CN113937483 A CN 113937483A
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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
- H01Q1/12—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
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/10—Resonant antennas
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/20—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements characterised by the operating wavebands
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
- H01Q5/30—Arrangements for providing operation on different wavebands
- H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
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Abstract
The invention discloses a low-profile anti-metal tag antenna applied to an ultrahigh frequency band, and belongs to the technical field of radio frequency identification electronic tags. The anti-metal tag antenna mainly comprises a dielectric substrate, an antenna conductor structure on the upper surface of the substrate, a metal conductor structure on the lower surface of the substrate and an RFID tag chip. The radiating patch is a T-shaped open stub feed structure and two symmetrical radiating slots, and the chip is positioned on the open stub. And second radiation gaps are formed on two sides of the U-shaped groove of the T-shaped radiation arm and the rectangular radiation patch, the resonant frequency of the antenna is adjusted by adjusting the width of the U-shaped groove, the impedance of the antenna is adjusted by adjusting the T-shaped radiation arm of the antenna, and the bandwidth of the tag antenna is adjusted by adjusting the width and the depth of the two parallel second radiation gaps. The resonant frequency of the anti-metal label antenna is 912MHz, the center frequency of the antenna is 880 MHz-940 MHz, the gain range of the center frequency band is-0.87 dBi-7.7 dBi, and the maximum identification distance under the metal environment is 6.02 m.
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) is a non-contact wireless communication technology, and has the advantages of high data transmission speed, high Identification precision, strong adaptability, strong anti-interference capability, and the like. With the development of society, ultrahigh frequency (UHF) RFID tags are also widely used in metal environments, and the radiation efficiency, the antenna impedance, the resonant frequency and other properties of the RFID tags are greatly reduced, and even the RFID tags cannot work normally. Therefore, designing an anti-metal microstrip tag antenna becomes one of the mainstream research directions, and the prior art adopts a bent open-circuit line structure to adjust the antenna impedance or increases the thickness of a dielectric layer to improve the anti-metal performance of the microstrip antenna. The thickness of the tag antenna designed in this way is usually 3mm or 2.2mm more, which is not beneficial to better adhering to the metal surface, the bandwidth of a general bent open line is narrower and usually 8MHz, and the resonant frequency of the general bent open stub tag antenna is basically fixed at 910MHz and cannot be adjusted.
Under the background, the invention designs a novel RFID anti-metal tag with two resonant frequency bands and a low profile, the RFID anti-metal tag has a bandwidth of 17MHz, the resonant frequency can be selected to be 840MHz or 910MHz by changing the size of the antenna, the two resonant frequency bands have higher return loss compared with a common bent open-circuit antenna, the RFID anti-metal tag can be better attached to a metal surface, and the resonant frequency of the antenna can be adjusted.
Disclosure of Invention
In order to solve the problems that the performance of the tag antenna is deteriorated in a metal environment, the size of the tag antenna is reduced, and the processing technology difficulty is high, the invention provides the low-profile metal-resistant tag antenna applied to the UHF frequency band, and the center frequency of the antenna can be adjusted to be 840MHz or 912MHz by changing the width of a radiation gap.
The utility model provides an anti metal label antenna of low section that is applied to ultrahigh frequency section includes radiation paster, dielectric substrate 5 and metal soleplate 6, the fixed top surface of locating dielectric substrate 5 of radiation paster, the radiation paster includes label chip 2, metal soleplate 6 is fixed to be located dielectric substrate 5's bottom surface, improves and lies in:
the radiation patch also comprises a rectangular radiation patch 3 and a T-shaped radiation arm 1;
one end of the rectangular radiation patch 3 in the length direction is U-shaped, the lower end of a vertical arm of the T-shaped radiation arm 1 is connected with the bottom in the U-shaped end of the rectangular radiation patch 3 through a tag chip 2, and two second radiation slits 7 are formed between two sides of the vertical arm of the T-shaped radiation arm 1 and two sides of a U-shaped groove of the rectangular radiation patch 3;
the other end of the rectangular radiation patch 3 in the length direction is provided with two first radiation slits 4 along the length direction, and the two first radiation slits 4 are parallel;
the thickness of the low-profile anti-metal tag antenna is not more than 1.6 mm;
when the width W4 of the first radiation slit 4 is 5mm and the width W5 of the second radiation slit 7 is 11mm, the resonant frequency of the anti-metal tag antenna becomes 913MHz, the return loss is-56 dB, the central frequency band is 880MHz to 940MHz, and the gain variation range in the central frequency band is-0.87 dBi to-7.7 dBi;
when the width W4 of the first radiation slit 4 is 13mm and the width W5 of the second radiation slit 7 is 3mm, the resonant frequency of the anti-metal tag antenna becomes 840MHz, the return loss is-65 dB, the central frequency band is 810MHz to 870MHz, and the gain variation range in the central frequency band is-1.78 dBi to-6.7 dBi.
The further technical scheme is as follows:
the radiation patch and the metal base plate 6 are made of copper sheets, and the thicknesses of the radiation patch and the metal base plate 6 are both 0.2 mm; the medium substrate 5 is made of FR4 and has a thickness of 1.6 mm.
The first radiation slits 4 are formed by a metal etching process, the slit width W6 of each first radiation slit 4 is 1mm, the slit length L4 is 38mm, and the distance between every two first radiation slits 4 is 24 mm.
The T-shaped radiating arm 1 consists of a horizontal arm and a vertical arm, wherein the horizontal arm is W2 multiplied by L2 and is 5mm multiplied by 4mm, and the vertical arm is W3 multiplied by (L6-L7) and is 8mm multiplied by 41 mm.
Compared with the prior art, the invention has the beneficial technical effects in the following aspects:
1. in terms of the thickness of the dielectric plate of the tag antenna, the thickness of the dielectric plate of a general open stub tag antenna is more than 3mm and 2.2mm, and the thickness of the tag antenna of the present invention is only 1.6 mm. In special occasions, the thickness of the label can be 1mm, and the return loss can still be ensured to be-12 dB. In the aspect of adjusting the impedance, the T-shaped radiating arm is adopted to replace a common bent open stub to adjust the impedance of the antenna, and when the length of the vertical arm of the T-shaped radiating arm 1 is adjusted between 42mm and 52mm, the return loss value of the T-shaped radiating arm is between-36 dB and-56 dB, so that the normal use requirement of the common antenna is met.
2. In the aspect of the bandwidth performance of the antenna, the bandwidth of the antenna is adjusted only by adjusting the width of the horizontal arm of the T-shaped radiating arm 1, and when the width of the horizontal arm of the T-shaped radiating arm 1 of the antenna is 5mm, the bandwidth of the antenna is 8MHz in-10 dB with the general bent open-circuit stub tag antenna; when the width of the horizontal arm of the T-shaped radiation arm 1 is adjusted to be 9mm, the bandwidth of the tag antenna is 16MHz at-10 dB, and the situation that a microstrip line is additionally added to excite two adjacent resonant modes to increase the bandwidth of the antenna is avoided. Therefore, the bandwidth of the tag antenna can be adjusted more conveniently by adjusting the horizontal arm width of the T-shaped radiation arm.
3. In terms of adjustment of the resonant frequency of the antenna, two resonant frequencies can be selected by changing the size of the second radiating slot 7, which are 840MHz or 912MHz, respectively. The width of the second radiating slot 7 is increased under the condition that the width of the T-shaped radiating arm 1 is kept unchanged, and the resonant frequency of the tag antenna is adjusted by changing the length of a current path on the surface of a radiating patch by using a meander technology. When the width of the second radiation slot 7 is 3mm, the resonant frequency of the tag antenna is 840MHz, and when the width of the second radiation slot 7 is increased to 6mm, the resonant frequency of the tag antenna is also 862MHz, and the resonant frequency can be adjusted between 840MHz and 862 Hz; when the width of the two symmetrical second radiating slots 7 is 10mm, the resonant frequency of the tag antenna is 900MHz, and when the width of the second radiating slot 7 is 13mm, the resonant frequency of the antenna is 912MHz, and the resonant frequency is adjusted within 900 MHz-912 MHz.
4. The tag antenna of the present invention is particularly added with two symmetrical first radiating slots 4, the width of the first radiating slot 4 is 1mm, and the distance between the two first radiating slots 4 is 24 mm. The two symmetrical first radiating slots 4 are equivalent to coupling capacitors in the radiating patch 1 of the antenna, and the impedance of the antenna is adjusted by adjusting the distance between the two symmetrical first radiating slots 4, and finally, impedance matching is achieved to compensate the return loss of the antenna loss.
5. Compared with a common bent open-circuit tag antenna, the structure of the invention is simpler, and the structure is not provided with a via hole short-circuit structure, so that the structure is more convenient to adjust and is beneficial to batch production.
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 graph of the power reflection function (S) of the metal-tag-resistant antenna of the present invention in a metal and nonmetal environment at a resonant frequency of 840MHz11）。
Fig. 6 is a Smith chart of the anti-metal tag antenna of the present invention.
Fig. 7 is a three-dimensional gain diagram of the anti-metal tag antenna of the present invention.
Fig. 8 is a reading distance diagram of the anti-metal tag antenna of the present invention under metal and non-metal environments.
Fig. 9 is a Smith chart of the anti-metal tag antenna according to the present invention when the resonant frequency of the anti-metal tag antenna is 912 MHz.
Fig. 10 is a graph of a power reflection function in a metallic and non-metallic environment when the resonant frequency of the anti-metallic tag antenna of the present invention is 912MHz (S11).
FIG. 11 is a graph of the read distance of the anti-metal tag antenna of the present invention in both metallic and non-metallic environments when the resonant frequency is 912 MHz.
Numbers in fig. 1 to 4: t-shaped radiation arm 1, label chip 2, antenna radiation face 3, first radiation slot 4, second radiation slot 7, dielectric substrate 5, metal bottom plate 6.
Detailed Description
The invention will now be further described by way of example with reference to the accompanying drawings.
Example 1
Referring to fig. 1, the low-profile metal-resistant tag antenna applied to the UHF band includes a tag chip 2, a radiation patch, a first radiation slot 4, a second radiation slot 7, a dielectric substrate 5, and a metal base plate 6, wherein the chip 2, the radiation patch, the first radiation slot 4, and the second radiation slot 7 are all disposed on an upper surface of the dielectric substrate, and the metal base plate 6 is disposed on a lower surface of the dielectric substrate.
Referring to fig. 2, the radiation patch includes a T-shaped radiation arm 1, a first radiation slot 4, a second radiation slot 7, and a radiation plane 3; the T-shaped radiation arm 1 is partially positioned outside the radiation surface 3, and the first radiation slot 4 and the second radiation slot 7 are positioned on the radiation surface 3; the chip 2 is located on a connecting line of the strip-shaped radiation arm 6 and the radiation surface 3, and feeds power to the chip through an open-circuit stub structure.
Referring to fig. 3 and 4, the first radiation slit 4 has dimensions W6 × L4 of 1mm × 38mm, and the second radiation slit 7 has dimensions W5 × L5 of 3mm × 30 mm. The T-shaped radiating arm 1 is composed of two rectangular patches, one having a size W2 × L2 of 52mm × 1mm and the other having a size W3 × (L6-L7) of 8mm × 41 mm. The dimensions of the dielectric substrate 5 and the metal base plate 6 are W1 × L1 and 60 × 118 mm. The dimensions W2=52mm, W3=8mm, W4=13mm, L2=4mm, L3=88mm, L5=30mm of the radiating surface 3.
The impedance and the resonant frequency of the tag antenna are adjusted by adjusting the length and the width of the T-shaped radiating arm and the length and the width of the first radiating slot 4 and the second radiating slot 7, the tag antenna is tested in a metal environment, the test result is shown in fig. 5, the central resonant frequency of the tag antenna in the metal environment is 840MHz, the return loss is-65 dB, the return loss is higher than that of a common antenna, the central resonant frequency of the tag antenna in the metal environment is 840MHz, the return loss is-31.31 dB, the tag antenna is not greatly influenced by the metal environment, and the tag antenna can be normally used.
As shown in fig. 5, the return loss curves of the metal-tag antenna according to the present invention under the metal environment and the nonmetal environment (S11);
as shown in fig. 6, which is a smith chart of the anti-metal tag antenna of the present invention, from the report of the experimental results, the impedance normalized impedance of the further center frequency of 840MHz is (1.008 +0.034 j) Ω.
As shown in fig. 7, which is a three-dimensional gain diagram of the anti-metal tag antenna of the present invention, the maximum gain obtained by the antenna at 840MHz operating frequency is-1.78 dB, which meets the design requirements.
As shown in fig. 8, the distance graph is read in a metal environment and a free space under an ideal matching state of the anti-metal tag of the present invention, the equivalent radiation power EIRP =33dBm output by the reader/writer, the sensitivity of the tag chip is-18 dBm, the calculation is performed by using a formula, and the calculation simulation result shows that the anti-metal tag has a good identification distance in both a metal environment and a non-metal environment.
Example 2
In this embodiment 2, the width W5 of the second radiation slit 7 is changed to 11mm, and the width W4 is changed to 5mm, and the resonant frequency of the anti-metal tag antenna is 912MHz, and the frequency range of-10 dB is 905MHz to 921 MHz.
As shown in fig. 9, which is a smith chart of the anti-metal tag antenna of the present invention, the impedance normalized impedance of the recenterfrequency 912MHz is (1.0251 +0.0057 j) Ω according to the report of the experimental result.
As shown in fig. 10, the power reflection function of the metal-tag antenna of the present invention is plotted in a metallic and non-metallic environment at a resonance frequency of 912MHz (S11).
As shown in fig. 11, it is a distance chart read under metal and nonmetal environments when the resonance frequency of the anti-metal tag antenna of the present invention is 912 MHz.
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 (4)
1. The utility model provides an anti metal label antenna of low section for ultrahigh frequency section, includes radiation paster, dielectric substrate (5) and metal soleplate (6), the fixed top surface of locating dielectric substrate (5) of radiation paster, the radiation paster includes label chip (2), the fixed bottom surface of locating dielectric substrate (5) of metal soleplate (6), its characterized in that:
the radiation patch further comprises a rectangular radiation patch (3) and a T-shaped radiation arm (1);
one end of the rectangular radiation patch (3) in the length direction is U-shaped, the lower end of a vertical arm of the T-shaped radiation arm (1) is connected with the bottom in the U-shaped end of the rectangular radiation patch (3) through a label chip (2), and two second radiation seams (7) are formed between two sides of the vertical arm of the T-shaped radiation arm (1) and two sides of a U-shaped groove of the rectangular radiation patch (3);
the other end of the rectangular radiation patch (3) in the length direction is provided with two first radiation slits (4) along the length direction, and the two first radiation slits (4) are parallel;
the thickness of the low-profile anti-metal tag antenna is not more than 1.6 mm;
when the width W4 of the first radiation slit (4) is 5mm and the width W5 of the second radiation slit (7) is 11mm, the resonance frequency of the anti-metal tag antenna becomes 913MHz, the return loss is-56 dB, the center frequency band is 880MHz to 940MHz, and the gain variation range in the center frequency band is-0.87 dBi to-7.7 dBi;
when the width W4 of the first radiation slit (4) is 13mm and the width W5 of the second radiation slit (7) is 3mm, the resonant frequency of the anti-metal tag antenna becomes 840MHz, the return loss is-65 dB, the central frequency band is 840MHz to 862MHz, and the gain variation range in the central frequency band is-1.78 dBi to-6.7 dBi.
2. The antenna of claim 1, wherein the antenna comprises: the radiation patch and the metal bottom plate (6) are made of copper sheets, and the thicknesses of the radiation patch and the metal bottom plate (6) are both 0.2 mm; the medium substrate (5) is made of FR4 and has a thickness of 1.6 mm.
3. The antenna of claim 1, wherein the antenna comprises: the first radiation slits (4) are formed by a metal etching process, the slit width W6 of each first radiation slit (4) is 1mm, the slit length L4 is 38mm, and the distance between every two first radiation slits (4) is 24 mm.
4. The antenna of claim 1, wherein the antenna comprises: the T-shaped radiation arm (1) consists of a horizontal arm and a vertical arm, wherein the horizontal arm is W2 multiplied by L2 and is 5mm multiplied by 4mm, and the vertical arm is W3 multiplied by (L6-L7) and is 8mm multiplied by 41 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111199421.8A CN113937483A (en) | 2021-10-14 | 2021-10-14 | Low-profile anti-metal tag antenna applied to ultrahigh frequency band |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111199421.8A CN113937483A (en) | 2021-10-14 | 2021-10-14 | Low-profile anti-metal tag antenna applied to ultrahigh frequency band |
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| CN113937483A true CN113937483A (en) | 2022-01-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202111199421.8A Pending CN113937483A (en) | 2021-10-14 | 2021-10-14 | Low-profile anti-metal tag antenna applied to ultrahigh frequency band |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117525862A (en) * | 2023-12-26 | 2024-02-06 | 青岛柯锐思德电子科技有限公司 | On-board miniaturized UWB antenna and angle measurement combination |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060145927A1 (en) * | 2004-12-08 | 2006-07-06 | Won-Kyu Choi | PIFA and RFID tag using the same |
| CN101355195A (en) * | 2008-08-29 | 2009-01-28 | 浙江大学 | UHF RF dual-frequency-recognizing metal-resistance label antenna |
| CN202042595U (en) * | 2011-04-20 | 2011-11-16 | 付宇卓 | Ultrahigh-frequency radio frequency identification electronic tag antenna capable of working on 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 |
-
2021
- 2021-10-14 CN CN202111199421.8A patent/CN113937483A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060145927A1 (en) * | 2004-12-08 | 2006-07-06 | Won-Kyu Choi | PIFA and RFID tag using the same |
| CN101355195A (en) * | 2008-08-29 | 2009-01-28 | 浙江大学 | UHF RF dual-frequency-recognizing metal-resistance label antenna |
| CN202042595U (en) * | 2011-04-20 | 2011-11-16 | 付宇卓 | Ultrahigh-frequency radio frequency identification electronic tag antenna capable of working on 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 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117525862A (en) * | 2023-12-26 | 2024-02-06 | 青岛柯锐思德电子科技有限公司 | On-board miniaturized UWB antenna and angle measurement combination |
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