CN117878569A - Multi-folding double-sided anti-metal RFID tag antenna - Google Patents
Multi-folding double-sided anti-metal RFID tag antenna Download PDFInfo
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Abstract
The invention discloses a multi-folding double-sided anti-metal RFID tag antenna, and belongs to the technical field of wireless communication. The antenna comprises a three-layer integrated folding structure which is sequentially formed by a top metal patch, a middle radiation patch and a bottom metal patch, and insulating substrates are arranged on two side surfaces of each layer of patch; the middle radiation patch comprises a radiation arm, a chip and an impedance matching adjusting loop; the impedance matching adjusting loop is annularly arranged in a shape like a Chinese character 'kou' and is fixedly connected with one end of the radiation arm; a feeding port is arranged at one end of the radiation arm, which is close to the impedance matching adjusting loop, and a chip is arranged at the feeding port; one side of the bottom metal patch is connected with the other end of the radiation arm through a first shorting stub, and the adjacent other side of the bottom metal patch is connected with the top metal patch through a second shorting stub. The invention can effectively improve the impedance matching between the chip and the antenna structure so as to realize good double-sided metal resistance, and has flexible use and wide application range.
Description
Technical Field
The invention relates to a multi-folding double-sided anti-metal RFID tag antenna, and belongs to the technical field of wireless communication.
Background
Radio frequency identification (Radio Frequency Identification, RFID) is a wireless communication technology that can identify specific targets by radio signals and read and write related data information, and is widely used in medical devices, inventory tracking, production management, and the like. The workflow of the RFID system is as follows: the tag antenna drives and loads a chip positioned in the tag by receiving energy sent by the reader-writer, and then sends a signal with chip information to the reader-writer, so that identification is completed in a radio frequency mode.
Along with popularization of the internet of things in various fields, application scenes of Radio Frequency Identification (RFID) tags gradually tend to be diversified, and some applications require that the tags be mounted on articles of different materials, such as glass, wood and even metal. However, the most significant of these attachment materials, particularly metals, can have a significant impact on antenna performance, even resulting in an antenna that is not functioning properly. Because most common RFID tag antennas are dipoles or folded dipoles, when the dipole antennas are clung to a metal plate, due to the mirror image principle, induced currents with the same magnitude and opposite phases as the dipole antenna currents are induced on the metal plate, so that radiation fields caused by the dipole antenna currents are interfered; meanwhile, the magnitude and the phase of the induced image current are equal to those of the current of the original tag antenna, and the radiation field of the image current and the radiation field of the original tag antenna are mutually offset, so that the original tag antenna cannot work normally.
In order to reduce the influence of the attached metal, a number of tag design methods have been proposed. In the prior art, the purpose of resisting metals is achieved by referring to a microstrip antenna or a planar inverted F antenna and the like. Microstrip antennas, also commonly referred to as patch antennas, the radiating patches and feed lines are typically attached to or etched in a dielectric substrate, with a metal floor on the other side of the substrate. The radiation patch is usually rectangular, prototype, dipole-shaped and the like, and the working frequency of the rectangular patch can be effectively changed by adjusting the side length of the rectangular patch. The shape of the interface between the radiation patch and the feeder line can be adjusted to effectively change the input impedance and impedance matching condition, and after the relevant parameters are adjusted, the microstrip antenna can show the characteristic of directional radiation; the planar inverted-F antenna is a monopole antenna parallel to the PCB, and the radiating patch is connected with the metal ground by a short-circuit arm on the basis of setting a feed source as excitation. Because of the introduction of the new short-circuit arm structure, the parameters of the short-circuit arm are optimized together with the conventional parameters (analog microstrip antenna) such as the metal patch, the feeder structure and the interface when the PIFA antenna is optimized. When the relevant parameters are adjusted, the PIFA antenna will exhibit directional radiation characteristics. Although various anti-metal tag antennas have been developed, most tag antennas can achieve only single-sided anti-metal performance and have poor anti-metal performance.
Disclosure of Invention
The invention aims to provide a multi-folding double-sided anti-metal RFID tag antenna, which aims to enlarge the application range of the tag antenna and ensure good corresponding anti-metal performance.
In order to solve the technical problems, the invention is realized by adopting the following technical scheme:
the invention provides a multi-folding double-sided anti-metal RFID tag antenna, which comprises a three-layer integrated folding structure formed by a top metal patch, a middle radiation patch and a bottom metal patch in sequence, wherein two side surfaces of each layer of patch are provided with insulating substrates;
the top metal patch can increase the heat dissipation area of the middle radiation patch, and the corresponding bottom metal patch can better couple the energy of the tag antenna with the metal backboard; the metal backboard is a plane large metal board for testing the antenna metal resistance.
The middle radiation patch comprises a radiation arm, a chip and an impedance matching adjusting loop; the impedance matching adjusting loop is annularly arranged in a shape like a Chinese character 'kou' and is fixedly connected with one end of the radiation arm; a feed port is arranged at one end, close to the impedance matching adjustment loop, of the radiation arm, and the chip is arranged at the feed port;
one side of the bottom metal patch is connected with the other end of the radiation arm through a first shorting tab, and the adjacent other side of the bottom metal patch is connected with the top metal patch through a second shorting tab.
The performances of the upper surface and the lower surface of the tag antenna designed by the invention when the upper surface and the lower surface are respectively clung to metal can be the same, and the gain effect of the antenna is good; meanwhile, through ingenious adjustment of impedance matching between the chip and the tag antenna, the scattering area of the tag antenna is enlarged, and the anti-metal purpose of the tag antenna is effectively improved.
Optionally, when the top metal patch, the middle radiation patch, and the bottom metal patch are in a folded state, the second shorting line faces away from the impedance matching adjustment loop and is disposed between the bottom metal patch and the top metal patch. The corresponding shorting stub is configured at a specific location to further adjust the impedance matching of the RFID chip and the tag antenna.
Alternatively, when each patch is in a folded configuration and in a metallic environment, the metallic loops on both sides of the folded configuration have the same resistance to metals. The tag antenna in the folded state can show the same high metal resistance in both the bottom metal patch and the metal backboard or the top metal patch and the metal backboard.
Optionally, the bottom metal patch and the top metal patch are rectangular, and the outer contour sizes of the bottom metal patch and the top metal patch are the same;
the overall outer contour of the middle radiating patch is adapted to the bottom metal patch and the top metal patch.
Optionally, the insulating substrate comprises an intermediate isolation layer and a substrate layer;
the middle isolation layer comprises a first middle isolation layer and a second middle isolation layer, and the first middle isolation layer and the second middle isolation layer are respectively arranged between the bottom metal patch and the middle radiation patch and between the middle radiation patch and the top metal patch through back glue;
the substrate layers are correspondingly covered on the lower surface of the bottom plate metal patch, the upper surface of the middle radiation patch and the lower surface of the second middle isolation layer and the upper surface of the top metal patch after being folded.
Optionally, the thickness of the first middle isolation layer is the same as that of the second middle isolation layer, and the thickness of the substrate layer is smaller than that of each middle isolation layer;
the shapes of the first middle isolation layer, the second middle isolation layer and the substrate layer are consistent with the shape of the middle radiation patch.
Alternatively, the substrate layer is a polyethylene terephthalate film or a polybutylene terephthalate film or a polyimide film.
Optionally, the process of forming the tag antenna by folding is:
setting the left side of the unfolded tag antenna as a middle radiation patch, the right side as a bottom metal patch, and the lower side of the bottom metal patch as a top metal patch;
adhering the first middle isolation layer to the upper surface of the bottom metal patch correspondingly, and turning the middle radiation patch right at the first shorting line to complete first folding;
adhering the second middle isolation layer to the upper surface of the folded middle radiation patch correspondingly, and upwards folding the top metal patch at the second shorting line to complete second folding;
the substrate layers are correspondingly covered on the lower surface of the bottom plate metal patch, the upper surface of the middle radiation patch and the lower surface of the second middle isolation layer and the upper surface of the top metal patch respectively.
Optionally, the first shorting stub is located in the middle of the left side surface of the antenna, and the second shorting stub is located at one end of the front side surface of the antenna, which is close to the first shorting stub.
Wherein the first shorting stub is connected to either the top metal patch or the bottom metal patch, the antenna achieves an anti-metal target. However, the design position of the second shorting stub has a qualitative relationship directly related to the impedance matching, so that, in order to improve the impedance matching between the chip and the antenna structure, the second shorting stub should be disposed as close to one end of the first shorting stub as possible on the front side of the antenna.
Compared with the prior art, the invention has the beneficial effects that:
the tag antenna mainly comprises three layers of patches, one side of the bottom metal patch is connected with the middle radiation patch through the first shorting stub, the other side of the bottom metal patch is connected with the top metal patch through the second shorting stub, and the folded tag antenna can achieve good double-sided metal resistance, and is compact in size and wide in application range; and the connection position of the second shorting stub is determined through adjustment, so that good impedance matching between the tag chip and the tag antenna is ensured, and the metal resistance is remarkably optimized.
Drawings
FIG. 1 is a top view of a multi-fold, dual-sided, metal-resistant RFID tag antenna of the present invention in a folded configuration;
FIG. 2 is a top view of a multi-fold dual-sided anti-metal RFID tag antenna of the present invention in a folded state and without a top metal patch and an insulating substrate;
FIG. 3 is a schematic diagram of a multi-folded dual-sided anti-metal RFID tag antenna in an unfolded state without an insulating substrate;
FIG. 4 is a left side view of the multi-fold, double-sided, metal-resistant RFID tag antenna of the present invention in a folded state;
FIG. 5 is a front view of a multi-fold, double-sided, metal-resistant RFID tag antenna of the present invention in a folded state;
FIG. 6 is a cross-sectional view of a multi-folded double-sided, metal-resistant RFID tag antenna corresponding to the direction A-A' in FIG. 1;
FIG. 7 is a graph showing simulation data of Z parameter (impedance parameter) when metal is attached to the front or back of the tag antenna according to the present invention;
FIG. 8 is a graph showing simulation data of S parameter (reflection coefficient) when metal is attached to the front or back of the tag antenna according to the present invention;
FIG. 9 is a graph showing simulation data of Gain when metal is attached to the front or back of the tag antenna according to the present invention;
FIG. 10 is a diagram showing the variation of the re portion of the z-function of the present invention;
FIG. 11 is a graph showing the variation of the rm portion of the z-function of the present invention;
fig. 12 is a schematic diagram showing the calculation result of the S parameter (reflection coefficient) of the present invention.
In the figure: 1-top metal patch; 2-a bottom metal patch; 3-radiating arms; 4-chip; a 5-impedance matching tuning loop; 6-a first shorting stub; 7-a second shorting stub; 8-a first intermediate barrier layer; 9-a second intermediate barrier layer; 10-a substrate layer; 11-a metal backplate; 12-mid-radiating patch.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
Example 1
Referring to fig. 1 to 3, the present embodiment provides a multi-folding double-sided anti-metal RFID tag antenna, which includes a three-layer integrated folded structure formed by a top metal patch 1, a middle radiation patch 12 and a bottom metal patch 2 in sequence, and insulating substrates are disposed on two sides of each layer of patch;
the middle radiation patch 12 comprises a radiation arm 3, a chip 4 and an impedance matching adjusting loop 5; the impedance matching adjusting loop 5 is annularly arranged in a shape like a Chinese character 'kou' and is fixedly connected with one end of the radiation arm 3; and a feed port is arranged at one end, close to the impedance matching adjustment loop 5, of the radiation arm 3, the chip 4 is arranged at the feed port, and the specific size corresponding to the chip placement area is 1mm multiplied by 1mm.
Wherein, the length of the radiation arm 3 can be adjusted to adjust the frequency in actual operation; correspondingly, the length and the width of the impedance matching adjusting loop 5 can be adjusted to adjust the impedance of the tag antenna, so that the impedance matching between the tag chip 4 and the tag antenna is ensured.
One side of the bottom metal patch 2 is connected with the other end of the radiation arm 3 through a first shorting tab 6, and the adjacent other side of the bottom metal patch 2 is connected with the top metal patch 1 through a second shorting tab 7.
The tag antenna in this embodiment is made up of three layers of patches, namely a lower bottom metal patch 2, a middle radiating patch 12 and an upper top metal patch 1, separated by a corresponding insulating substrate. In the use process of the antenna, if the bottom metal patch 2 is attached to the metal backboard, the tag antenna is called front attachment; if the top metal patch 1 is attached to the metal back plate 11, the tag antenna is referred to as a reverse-side attachment. The metal back plate 11 is a planar large metal plate for testing the antenna metal resistance, and the overall size is not smaller than 150mm by 150mm. Specifically, if the tag antenna is placed in a metal environment, the patch contacting the metal back plate 11 may be regarded as a ground layer of the folded patch antenna, the conductor layer and the intermediate layer corresponding to the two patches on the other side may be regarded as radiation layers of the antenna, and the performances of the tag antenna when the upper and lower surfaces of the tag antenna are respectively attached to the metal are all ensured to be the same, and the antenna gains are all good.
Example 2
On the basis of example 1, this example also has the following design:
when the top metal patch 1, the middle radiating patch 12 and the bottom metal patch 2 are in a folded state, the second shorting stub 7 faces away from the impedance matching adjustment loop 5 and is disposed between the bottom metal patch 2 and the top metal patch 1.
The bottom metal patch 2 and the top metal patch 1 are rectangular, and the outer contour sizes of the bottom metal patch 2 and the top metal patch 1 are the same;
the overall outer contour of the central radiating patch 12 is adapted to the bottom metal patch 2 and the top metal patch 1.
Referring to fig. 4 to 6, the insulating substrate includes an intermediate isolation layer and a base material layer 10;
the middle isolation layer comprises a first middle isolation layer 8 and a second middle isolation layer 9, and the first middle isolation layer 8 and the second middle isolation layer 9 are respectively arranged between the bottom metal patch 2 and the middle radiation patch 12 and between the middle radiation patch 12 and the top metal patch 1 through back glue;
the substrate layer 10 is correspondingly covered on the lower surface of the bottom plate metal patch 2, the upper surface of the middle radiation patch 12 and the lower surface of the second middle isolation layer 9 and the upper surface of the top metal patch 1 after being folded, wherein the substrate layer 10 is made of polyethylene terephthalate film or polybutylene terephthalate film or polyimide film.
The thickness of the first middle isolation layer 8 is the same as that of the second middle isolation layer 9, and the thickness of the base material layer 10 is smaller than that of each middle isolation layer;
the shapes of the first middle isolation layer 8, the second middle isolation layer 9 and the base material layer 10 are consistent with the shape of the middle radiation patch 12.
Specifically, referring to fig. 3, the process of forming the tag antenna by folding each patch in this embodiment is as follows:
setting the left side of the unfolded tag antenna as a middle radiation patch 12, the right side as a bottom metal patch 2, and the lower side of the bottom metal patch 2 as a top metal patch 1;
adhering the first middle isolation layer 8 to the upper surface of the bottom metal patch 2 correspondingly, and turning the middle radiation patch 12 to the right at the first shorting tab 6 to complete the first folding;
adhering the second middle isolation layer 9 to the upper surface of the folded middle radiation patch 12 correspondingly, and turning the top metal patch 1 upwards at the second shorting tab 7 to complete second folding;
wherein, the substrate layer 10 is correspondingly covered on the lower surface of the bottom metal patch 2, the upper surface of the middle radiation patch 12 and the lower surface of the second middle isolation layer 9, and the upper surface of the top metal patch 1.
The first shorting stub 6 is located in the middle of the left side surface of the antenna, and the second shorting stub 7 is located at one end of the front side surface of the antenna, which is close to the first shorting stub 6.
The tag antenna in the embodiment adopts an integrated folding structure, so that the tag antenna is simple in structural design and compact in size, and has excellent metal resistance due to the symmetrical characteristic of the tag antenna after being folded, namely, the front side and the back side of the tag antenna can be provided with excellent metal resistance; meanwhile, the optimized position of the corresponding shorting stub is set, so that the impedance matching between the tag chip and the tag antenna is effectively ensured.
It should be noted that, in this embodiment, by changing the structure of the tag antenna, the tag antenna can work normally when the front and back surfaces of the tag antenna are respectively attached to the metal plates, namely: when each patch is in a folded state and under a metal environment, the metal resistance of the metal loops on the two sides of the folded state is the same, so that the problem of metal resistance on the two sides of the RFID tag antenna is solved. Referring to fig. 7 to 9, the implementation process of the simulation experiment is specifically described as follows:
1.1, experimental scenes
The maximum power of the antenna of the handheld reader-writer used in the embodiment is 33dBm, and the reading and writing distance L of the handheld reader-writer handset Exceeding 5m. The laboratory frequency sweep device is used for carrying out a read-write distance experiment on the antenna from 800MHz to 1000MHz, and the laboratory frequency sweep device reads and writes a distance L lab Exceeding 10m.
The relation between the laboratory sweep frequency read-write distance and the hand-held reader-writer distance is as follows: l (L) lab ＝2*L handset 。
1.2, experimental details
(1) The front surface of the tag antenna is attached to the metal backboard, and the specific steps are as follows:
on commercial software ANSYS HFSS, a system simulation was performed on front-side-attached anti-metal labels along with a metal back plate. After modeling is completed, simulation is performed to obtain Z parameters, wherein the Z parameters are expressed as impedance parameters of the tag antenna, and referring to FIG. 4, the abscissa is frequency (unit: GHz), the ordinate is impedance value (unit: ohm), red represents a real part re of the impedance value, green represents an imaginary part im of the impedance value, and the overall rule of the impedance parameters of the antenna structure along with the change of the frequency is expressed;
further, calculating an S parameter according to the Z parameter, wherein the S parameter is expressed as a reflection coefficient of a tag antenna, referring to FIG. 4, the abscissa represents frequency (unit: GHz), the ordinate represents the reflection coefficient of the antenna, namely the S parameter, and the whole represents the rule of the reflection coefficient (namely the S parameter) of the antenna structure along with the change of the frequency;
simulation verification is carried out on commercial software ANSYS HFSS, a Gain simulation calculation result is calculated, and referring to fig. 6, the abscissa represents frequency (unit: GHz), the ordinate represents antenna Gain, and the overall represents the Gain variation law of the antenna structure along with frequency;
the tag antenna is attached to the metal backboard in front, and the read-write distance L is tested by utilizing a laboratory sweep frequency device lab The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the yellow curve represents the front lamination test result;
subsequently, the read-write distance L is measured by a hand-held reader-writer handset 。L handset >5m。
(2) The reverse side of the tag antenna is attached to the metal backboard, and the specific steps are as follows:
likewise, on commercial software ANSYS HFSS, a system simulation was performed on front-side-attached anti-metal labels along with a metal back-plate. After modeling is completed, simulation is performed to obtain Z parameters, wherein the Z parameters are expressed as impedance parameters of the tag antenna, and referring to FIG. 4, the abscissa is frequency (unit: GHz), the ordinate is impedance value (unit: ohm), red represents a real part re of the impedance value, green represents an imaginary part im of the impedance value, and the overall rule of the impedance parameters of the antenna structure along with the change of the frequency is expressed;
further, calculating an S parameter according to the Z parameter, wherein the S parameter is expressed as a reflection coefficient of a tag antenna, referring to FIG. 5, the abscissa represents frequency (unit: GHz), the ordinate represents the reflection coefficient of the antenna, namely the S parameter, and the whole represents the rule of the reflection coefficient (namely the S parameter) of the antenna structure along with the change of the frequency;
simulation verification is carried out on commercial software ANSYS HFSS, a Gain simulation calculation result is calculated, and referring to fig. 6, the abscissa represents frequency (unit: GHz), the ordinate represents antenna Gain, and the overall represents the Gain variation law of the antenna structure along with frequency;
the reverse side of the tag antenna is attached to a metal backboard, and a laboratory sweep frequency device is used for testing the read-write distance L lab . The red curve represents the reverse lamination test result;
subsequently, the read-write distance L is measured by a hand-held reader-writer handset 。L handset >5m。
According to the simulation experiment, the double-sided anti-metal RFID tag can effectively achieve the characteristic of double-sided anti-metal, and when any side contacts with a metal backboard, the available frequency band can be covered by the application frequency band of the ultra-high frequency RFID tag antenna of the main country, so that the double-sided anti-metal RFID tag can be applied to the related measurement field of the complex industrial Internet of things with high adaptability.
It should be noted that there is no metal conductive connection between the top metal patch 1 and the middle radiation patch 12, and the top metal patch 1 and the bottom metal patch 2 are selectively connected through metal conductive connection at a specific position, and the impedance matching between the RFID chip 4 and the tag antenna can be further adjusted by setting the specific position. Referring to fig. 10 to 12, the implementation process of the simulation experiment is specifically described as follows:
2.1, parameter description
As shown in fig. 2 and 3, the direction of the loop structure from the first shorting stub to the middle radiation patch 12 is set as the y direction, and two relevant parameters for setting the second shorting stub 7 in this embodiment are respectively a position parameter S1 (specific position corresponding to the second shorting stub 7 in the y direction) and a length parameter S2 (width of the second shorting stub 7 itself, and width is also along the y axis). Wherein, the smaller the S1 value is, the closer the second shorting line 7 is to the y-axis positive direction, and the larger the S1 value is, the closer the second shorting line 7 is to the y-axis negative direction; the smaller the S2 value, the narrower the line width of the second shorting line 7, and the larger the S2 value, the wider the line width of the second shorting line 7.
2.2 Experimental details
Taking s1=5 mm and s2=10 mm as examples, when the width of the second shorting stub 7 is smaller, the second shorting stub approaches to the positive y axis direction, and fails to show a better qualitative rule due to the influence of the corresponding loop; further, the qualitative rule is thus increasingly good when the second shorting stub 7 is positioned progressively farther from the loop structure in the central radiating patch 12.
With increasing s1 value, the maximum value of the re part of the z parameter is only moved in one direction to the left (approximately 10MHz for every 11mm increase in s1 parameter); the im part of the z parameter varies with the same law.
From this, it can be deduced that the specific setting position of the second shorting stub 7 can specifically and effectively influence the changes in re and im in the z function, thereby influencing the matching of the reflection coefficient S11.
In the moving process, as the values of re and im continuously change, the values of re and im meeting the conjugate impedance matching of the chip of the model are obtained, and the good impedance matching can be obtained under a certain preset frequency by checking the S11 parameter.
Wherein, at 880MHz, with reference to fig. 10 to 12, S11 matches well when it comes to-10.5 dB (s1=s2=10mm); at the same time, the other patterns under the structure have no change, and the maximum gain has almost no change.
Further, when the width of the second shorting stub 7 is widened from 10mm to 15mm, the location of the shorting stub still has a significant effect on the z parameters re and im. Next, the S11 parameter is examined. From the S11 parameter, it is known that: by adjusting the shorting stub position, impedance matching adjustment at a predetermined frequency (880 MHz) is achieved.
S1=5 when s2=20 mm; 10;15;20, a step of; 25, a step of selecting a specific type of material; 30;35;40, a step of performing a; 45;50, the change rule is the same as above, and the following parameters are known from the S11: by adjusting the position of the shorting stub, impedance matching adjustment at a predetermined frequency (880 MHz) is achieved, particularly when s1=30mm and s2=20mm, the corresponding reflection coefficient is-11.3 db@880mhz.
S1=5 when s2=25 mm; 10;15;20, a step of; 25, a step of selecting a specific type of material; 30;35;40, a step of performing a; 45;50;55; at 60, the change rule is the same as above. The corresponding reflection coefficient of the process is-10.9 dB@880MHz.
S1=5 when s2=30 mm; 10;15;20, a step of; 25, a step of selecting a specific type of material; 30;35;40, a step of performing a; 45;50;55; at 60, the change rule is the same as above. Specifically, s1=60 mm, s2=30 mm, and the corresponding reflection coefficient is-14.3 db@880mhz.
Referring to fig. 2 and 3, the values of specific parameters (i.e., s1 parameter and s2 parameter) of the second shorting bar 7 are selected, and s1=60 mm and s2=30 mm are selected according to the calculation results, and the reflection coefficient is the minimum value at this time, which indicates that the matching result of the conjugate impedance between the antenna and the chip is the best, and referring to table 1 specifically. Wherein Name represents variable Name, value represents expression, unit represents Unit, and Evaluated Value represents Value; w1 represents one section of the whole length of the radiation arm 4, W2 represents the other section corresponding to the whole length of the radiation arm 4, W3 represents the whole width of the impedance matching adjustment loop 5, L3 represents the whole length of the impedance matching adjustment loop 5, L2 represents the whole width of the radiation arm 4, a1 and a2 respectively represent the distances from the boundary of the cavity corresponding to the impedance matching adjustment loop to the whole outer boundary of the loop, s1 represents the corresponding specific position of the second shorting wire 7 in the y direction, s2 represents the width of the second shorting wire 7, and the width is also along the y axis direction.
TABLE 1
Thus, according to the above analysis, when the second shorting stub 7 is not added, the reflection coefficient S11 (i.e., impedance matching) of the antenna structure is optimal between-6 dB and-7 dB;
after the second shorting stub 7 is added, the reflection coefficient S11 (i.e., impedance matching) of the antenna structure may be less than-10 dB, effectively improving the impedance matching of the RFID chip 4 and the antenna structure.
Wherein, specific expressions corresponding to s1 and s2 parameters in the simulation experiment process can be specifically referred to table 2. Wherein Command represents an operation, coordinate system represents a coordinate system, position represents a start point coordinate of a rectangle corresponding to the tag antenna, axis represents a normal vector direction of a plane where the rectangle is located, Y size represents a projection length in a Y-Axis direction from the start point coordinate of the rectangle, and Z size represents a projection length in a Z-Axis direction from the start point coordinate of the rectangle; correspondingly, the creating Rectangle represents creating a Rectangle, global represents a Global coordinate system, 0.5X (l 3), w2-2mm-s1,0.5mm represents a specific expression of a rectangular starting point coordinate, X represents a plane normal vector direction of the Rectangle is an X-axis direction, s2 represents a length projection expression along a Y-axis direction from the rectangular starting point coordinate, and-1 represents a length projection along a Z-axis direction from the rectangular starting point coordinate.
TABLE 2
In the description of the present application, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or an implicit indication of the number of technical features being indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present disclosure/application, unless otherwise indicated, the meaning of "a plurality" is two or more;
meanwhile, it should be noted that, unless explicitly stated and limited otherwise, the terms "connected" and "connected" should be interpreted broadly, and for example, they may be mechanical connection or electrical connection; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present disclosure/application can be understood by those of ordinary skill in the art in a specific case.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.
Claims (9)
1. The multi-folding double-sided anti-metal RFID tag antenna is characterized by comprising a three-layer integrated folding structure which is sequentially formed by a top metal patch (1), a middle radiation patch (12) and a bottom metal patch (2), wherein insulating substrates are arranged on two side surfaces of each layer of patch;
the middle radiation patch (12) comprises a radiation arm (3), a chip (4) and an impedance matching adjusting loop (5); the impedance matching adjusting loop (5) is annularly arranged in a shape like a Chinese character 'kou' and is fixedly connected with one end of the radiation arm (3); a feed port is arranged at one end, close to the impedance matching adjusting loop (5), of the radiation arm (3), and the chip (4) is arranged at the feed port;
one side of the bottom metal patch (2) is connected with the other end of the radiation arm (3) through a first shorting stub (6), and the adjacent other side of the bottom metal patch (2) is connected with the top metal patch (1) through a second shorting stub (7).
2. The multi-fold double-sided, metal-resistant RFID tag antenna according to claim 1, characterized in that the second shorting line (7) faces away from the impedance matching tuning loop (5) and is arranged between the bottom metal patch (2) and the top metal patch (1) when the top metal patch (1), the middle radiating patch (12) and the bottom metal patch (2) are in a folded state.
3. The multi-fold, double-sided, metal-resistant RFID tag antenna of claim 2, wherein the metal loops on both sides of the folded state have the same metal resistance when each patch is in the folded state and in a metal environment.
4. A multi-fold double-sided, metal-resistant RFID tag antenna according to claim 3, characterized in that the bottom metal patch (2) and the top metal patch (1) are rectangular and the outer dimensions of the bottom metal patch (2) and the top metal patch (1) are the same;
the overall outline of the middle radiation patch (12) is matched with the bottom metal patch (2) and the top metal patch (1).
5. The multi-fold, double-sided, metal-resistant RFID tag antenna of claim 4, wherein the insulating substrate comprises an intermediate isolation layer and a substrate layer (10);
the middle isolation layer comprises a first middle isolation layer (8) and a second middle isolation layer (9), and the first middle isolation layer (8) and the second middle isolation layer (9) are respectively arranged between the bottom metal patch (2) and the middle radiation patch (12) and between the middle radiation patch (12) and the top metal patch (1) through back glue;
the substrate layer (10) is correspondingly covered on the lower surface of the bottom plate metal patch (2), the upper surface of the middle radiation patch (12) and the lower surface of the second middle isolation layer (9) and the upper surface of the top metal patch (1) after the folding state.
6. The multi-fold, double-sided, metal-resistant RFID tag antenna according to claim 5, characterized in that the first intermediate spacer layer (8) and the second intermediate spacer layer (9) have the same thickness, and the thickness of the substrate layer (10) is smaller than the thickness of each intermediate spacer layer;
the shapes of the first middle isolation layer (8), the second middle isolation layer (9) and the base material layer (10) are consistent with the shape of the middle radiation patch (12).
7. The multi-fold, double-sided, metal-resistant RFID tag antenna of claim 5, wherein the substrate layer (10) is a polyethylene terephthalate film or a polybutylene terephthalate film or a polyimide film.
8. The multi-fold, double-sided, metal-resistant RFID tag antenna of claim 5, wherein the process of forming the tag antenna by folding is:
setting a middle radiation patch (12) at the left side of the unfolded tag antenna, a bottom metal patch (2) at the right side, and a top metal patch (1) at the lower side of the bottom metal patch (2);
adhering the first middle isolation layer (8) to the upper surface of the bottom metal patch (2) correspondingly, and turning the middle radiation patch (12) right at the first shorting bar (6) to complete the first folding;
adhering the second middle isolation layer (9) to the upper surface of the folded middle radiation patch (12) correspondingly, and turning up the top metal patch (1) at the second shorting stub (7) to complete second folding;
the lower surface of the bottom plate metal patch (2), the upper surface of the middle radiation patch (12) and the lower surface of the second middle isolation layer (9) and the upper surface of the top metal patch (1) are correspondingly covered with the substrate layer (10) respectively.
9. The multi-fold, double-sided, metal-resistant RFID tag antenna of claim 8, wherein the first shorting stub (6) is located in the middle of the antenna left side, and the second shorting stub (7) is located at the front antenna side near one end of the first shorting stub (6).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410205883.3A CN117878569A (en) | 2024-02-26 | 2024-02-26 | Multi-folding double-sided anti-metal RFID tag antenna |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410205883.3A CN117878569A (en) | 2024-02-26 | 2024-02-26 | Multi-folding double-sided anti-metal RFID tag antenna |
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| Publication Number | Publication Date |
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| CN117878569A true CN117878569A (en) | 2024-04-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410205883.3A Pending CN117878569A (en) | 2024-02-26 | 2024-02-26 | Multi-folding double-sided anti-metal RFID tag antenna |
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| Country | Link |
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| CN (1) | CN117878569A (en) |
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- 2024-02-26 CN CN202410205883.3A patent/CN117878569A/en active Pending
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