Antenna of radio frequency identification tag

Abstract

The invention discloses an antenna of a radio frequency identification tag. The antenna comprises an antenna radiating element and a loop antenna, the antenna radiation element comprises a connecting part, a first winding radiation element and a second winding radiation element. The connecting part comprises a first end and a second end, and the connecting part has a length direction. The first winding radiation element extends out of the first end of the connecting part and is provided with a first winding belt shaft, and the first winding belt shaft is not parallel to the length direction. The second winding radiation element extends out of the second end of the connecting part and is provided with a second winding belt shaft, and the second winding belt shaft is not parallel to the length direction. The loop antenna is located between the first winding radiation element and the second winding radiation element, and the loop antenna is connected with the antenna radiation element without a conductor. The radio frequency identification tag can provide satisfactory radiation intensity in all directions.

Description

Technical Field

[0001] The invention relates to the field of product identification, and in particular to an antenna for a wireless radio frequency identification tag. Background Art

[0002] In logistics management, radio frequency identification tag technology improves logistics efficiency and reduces costs. The radiation pattern of existing radio frequency identification tags is usually bidirectional, resulting in weak radiation intensity in the direction perpendicular to the antenna, which limits the application of radio frequency identification tags. In addition, when radio frequency identification tags are attached to logistics packaging boxes or other media, they may cause the entire operating frequency band to shift or affect the overall performance, which is also a difficulty in designing radio frequency identification tags. Therefore, a more novel radio frequency identification tag technology is urgently needed. Summary of the invention

[0003] An object of the present invention is to provide an antenna for a radio frequency identification tag, which can provide satisfactory radiation intensity in all directions.

[0004] In some embodiments, an antenna for a wireless radio frequency identification tag includes:

[0005] Antenna radiating element, comprising:

[0006] A connecting portion, comprising a first end and a second end, and the connecting portion has a length direction;

[0007] A first meandering radiating element extending from the first end of the connecting portion, the first meandering radiating element having a first meandering axis, the first meandering axis being non-parallel to the length direction; and

[0008] a second meandering radiating element extending from the second end of the connecting portion, the second meandering radiating element having a second meandering axis, the second meandering axis being non-parallel to the length direction; and

[0009] The loop antenna is located between the first meandering radiating element and the second meandering radiating element, and there is no conductive body connecting the loop antenna and the antenna radiating elements.

[0010] In some embodiments, the first meandering zone axis and the second meandering zone axis are substantially perpendicular to the length direction.

[0011] In some embodiments, the loop antenna includes a first portion adjacent to the connecting portion and a second portion away from the connecting portion, the second portion includes a first open end and a second open end opposite to each other, and the loop antenna does not include other open ends except the first open end and the second open end.

[0012] In some embodiments, the loop antenna further includes a first meandering portion and a second meandering portion, wherein the second meandering portion is opposite to the first meandering portion.

[0013] In some embodiments, the loop antenna has an axial length substantially parallel to the length direction, and the meandering width of each of the first meandering portion and the second meandering portion is less than half of the axial length of the loop antenna.

[0014] In some embodiments, the axial length is smaller than a length of the connecting portion.

[0015] In some embodiments, the meandering zone axis of the first meandering portion is substantially parallel to the first meandering zone axis, and the meandering zone axis of the second meandering portion is substantially parallel to the second meandering zone axis.

[0016] In some embodiments, the antenna radiating element further includes a first radiating block and a second radiating block, wherein the first radiating block extends from an end of the first meandering radiating element, and the second radiating block extends from an end of the second meandering radiating element.

[0017] In some embodiments, the length direction of the first radiation block and the length direction of the second radiation block are substantially parallel to the length direction of the connecting portion.

[0018] In some embodiments, the first meandering radiation element and the second meandering radiation element have a first meandering band width and a second meandering band width, respectively, the length of the first radiation block is greater than or equal to the first meandering band width, the length of the second radiation block is greater than or equal to the second meandering band width, and the spacing between the first radiation block and the second radiation block is 1 mm to 12 mm.

[0019] In some embodiments, the first meandering radiating element comprises a plurality of first short line segments and a plurality of first long line segments that are alternately arranged and connected, the initiator of each of the first short line segments extends from the first end, each of the first short line segments is not parallel to each of the first long line segments, and the number of each of the first long line segments is an even number, and the second meandering radiating element comprises a plurality of second short line segments and a plurality of second long line segments that are alternately arranged and connected, the initiator of each of the second short line segments extends from the second end, each of the second short line segments is not parallel to each of the second long line segments, and the number of each of the second long line segments is an even number.

[0020] In some embodiments, the first meandering radiating element and the second meandering radiating element are mirror images of each other. In some embodiments, the distance between the loop antenna and the connecting portion is 0.2 mm to 1 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. 1 is a schematic top view of an antenna of a radio frequency identification tag in some embodiments of the present invention.

[0022] Figure 2 FIG. 1 is a schematic top view of an antenna of a radio frequency identification tag in some other embodiments of the present invention.

[0023] Figure 3 The results of using a “Tagformance” device to measure the antenna sensitivities of the first meandering portion and the second meandering portion at different meandering band widths in some embodiments of the present invention are shown.

[0024] Figure 4 FIG. 1 is a schematic top view of the antenna of the radio frequency identification tag of Comparative Example 1 of the present invention.

[0025] Figure 5 1 is a simulation result of the radiation pattern of the antenna 10C of Comparative Example 1 at 920 MHz.

[0026] Figure 6 The following are the simulation results of the radiation pattern of the antenna at 920 MHz in some embodiments of the present invention.

[0027] Figure 7 Schematic diagram of a top view of the antenna of the radio frequency identification tag of Comparative Example 2 of the present invention. Description of main reference numerals:

[0028] 10A, 10B, 10C, 10D: RFID tag antennas

[0029] 100: Antenna radiating element

[0030] 110: Connection

[0031] 111: First End

[0032] 112: Second end

[0033] 210, 210C: first meandering radiation element

[0034] 211: First short line segment

[0035] 212: The first long line segment

[0036] 214: The End

[0037] 320, 320C: Second meandering radiating element

[0038] 321: Second short line segment

[0039] 322: The second longest line segment

[0040] 324: end of the second meandering radiating element 320

[0041] 400, 400", 400D: Loop antenna

[0042] 410: Part 1

[0043] 420: Part 2

[0044] 431: First open end

[0045] 432: Second open end

[0046] 450: First winding section

[0047] 450W, 460W: Meandering belt width

[0048] 460: Second winding section

[0049] 510: First radiation block

[0050] 512: Second radiation block

[0051] A1, C1: first meandering belt axis

[0052] A2, C2: Second meandering belt axis

[0053] A3, A4: Meandering belt axis

[0054] D1, D2, D3: length direction

[0055] L1, L2, L4: Length

[0056] L3: axial length

[0057] G1, G2: Spacing

[0058] W1: Width of the first meandering belt

[0059] W2: Width of the second meandering belt

[0060] x, y: direction; DETAILED DESCRIPTION

[0061] Figure 1 1 is a top view of an antenna 10A of a radio frequency identification tag in some embodiments of the present invention. The antenna 10A of the radio frequency identification tag includes an antenna radiating element 100 and a loop antenna 400. The antenna radiating element 100 includes a connecting portion 110, a first meandering radiating element 210, and a second meandering radiating element 320. In various embodiments, the connecting portion 110, the first meandering radiating element 210, and the second meandering radiating element 320 are conductive bodies.

[0062] The connecting portion 110 includes a first end 111 and a second end 112, and the connecting portion 110 has a length direction D1, and the above-mentioned "length direction" can also be called a longitudinal direction. In some embodiments, the connecting portion 110 includes a straight line, a broken line, or a curve with an appropriate width, but in other embodiments, the appearance profile of the connecting portion 110 can be an ellipse, a wedge, a symmetrical double wedge, or other shapes. In some embodiments, the first end 111 and the second end 112 of the connecting portion 110 are substantially located on opposite sides of the length direction D1 of the connecting portion 110, and substantially define the length of the connecting portion 110; but in other embodiments, the first end 111 and the second end 112 can be located in the middle part of the connecting portion 110 or other positions.

[0063] The first meandering radiation element 210 extends from the first end 111 of the connecting portion 110. In detail, the first meandering radiation element 210 meanders in a planar belt-shaped area, and the first meandering radiation element 210 has a first meandering belt width W1 and a first meandering belt axis A1. The first meandering radiation element 210 turns at the outermost edges on both sides of the "first meandering belt". The first meandering belt (meander belt, originally "meander belt") is roughly the entire belt-shaped area occupied by the first meandering radiation element 210 turning and meandering. The width of the first meandering belt is defined as the first meandering belt width W1, and the first meandering belt axis A1 is a center line drawn according to the first meandering belt. The first meandering radiation element 210 generally extends left and right with the first meandering belt axis A1 as the center line. The definitions and descriptions of "meandering belt" and "meander-belt axis" in geographical science can be applied in the same or analogous manner to explain the "meandering belt" and "meander belt axis" described in this article.

[0064] In some embodiments, the first meandering belt axis A1 is substantially a straight line, but in other embodiments, the first meandering belt axis A1 is a polyline formed by connecting multiple straight lines, such as a simple polyline or a monotone polyline, or the first meandering belt axis A1 can be a curve.

[0065] In some embodiments, the first meandering radiating element 210 includes a plurality of first short line segments 211 and a plurality of first long line segments 212 that are alternately arranged and connected. One of the first short line segments 211 (e.g., the initial first short line segment 211) extends directly from the first end 111, and each first short line segment 211 is not parallel to each first long line segment 212. In some embodiments, each first short line segment 211 forms an angle of about 60 degrees to about 120 degrees with the connected first long line segment 212, such as about 60 degrees, about 70 degrees, about 80 degrees, about 90 degrees, about 100 degrees, about 110 degrees, or about 120 degrees. In some embodiments, each first long line segment 212 substantially extends along the length direction D1. In some other embodiments, the length of the first long line segment 212 actually defines the first meandering strip width W1, and the length of each first long line segment 212 is about 6 mm to about 16 mm, and the length of each first short line segment 211 is about 0.2 mm to about 3 mm. In some other embodiments, each first short line segment 211 is substantially a straight line, an arc or a curve. In other embodiments, each first long line segment 212 is substantially a straight line, an arc or a curve.

[0066] In some embodiments, the number of the first long line segments 212 is an even number, such as 2, 4, 6, 8 or more, and this technical feature provides excellent technical effects. Figure 1 The arrow symbols "→", "←", "↑", and "↓" in the figure illustrate the current flow obtained according to the computer simulation software (Ansys HFSS). When each first long line segment 212 substantially extends along the direction x, the current distribution of the even number of first long line segments 212 in the x direction cancels each other out during far-field radiation. However, the first short line segment 211 can still provide effective radiation in the vertical direction y (direction y is perpendicular to direction x). Therefore, such a design can improve the radiation intensity of the wireless radio frequency identification tag in the y direction (i.e., the vertical direction), and is beneficial to provide a radiation field pattern that is approximately spherical.

[0067] The second meandering radiating element 320 extends from the second end 112 of the connecting portion 110, and the second meandering radiating element 320 has a second meandering belt axis A2 and a second meandering belt width W2. The meanings of the second meandering belt, the second meandering belt width W2, and the second meandering belt axis A2 are as described above with respect to the first meandering radiating element 210. In some embodiments, the second meandering belt axis A2 is substantially a straight line, but in other embodiments, the second meandering belt axis A2 is a fold line formed by connecting a plurality of straight lines, such as a simple fold line or a monotonous fold line, or the second meandering belt axis A2 can be a curve.

[0068] The first meandering zone axis A1 of the first meandering radiating element 210 and the second meandering zone axis A2 of the second meandering radiating element 320 are not parallel to the length direction D1 of the connecting portion 110. In some embodiments, the first meandering zone axis A1 and the second meandering zone axis A2 respectively form an angle of about 60 degrees to about 120 degrees with the length direction D1 of the connecting portion 110, such as about 60 degrees, about 70 degrees, about 80 degrees, about 90 degrees, about 100 degrees, about 110 degrees, or about 120 degrees. In some embodiments, the first meandering zone axis A1 and the second meandering zone axis A2 are each substantially a straight line, and the first meandering zone axis A1 and the second meandering zone axis A2 are each substantially perpendicular to the length direction D1. In some other embodiments, the first meandering zone axis A1 is not parallel to the second meandering zone axis A2, and the acute angle formed by the first meandering zone axis A1 and the length direction D1 is substantially equal to the acute angle formed by the second meandering zone axis A2 and the length direction D1.

[0069] In some embodiments, the second meandering radiating element 320 includes a plurality of second short line segments 321 and a plurality of second long line segments 322 that are alternately arranged and connected. One of the second short line segments 321 (the initial second short line segment 321) extends directly from the second end 112, and each second short line segment 321 is not parallel to each second long line segment 322. In some embodiments, the second short line segment 321 and the second long line segment 322 form an angle of about 60 degrees to about 120 degrees, such as about 60 degrees, about 70 degrees, about 80 degrees, about 90 degrees, about 100 degrees, about 110 degrees, or about 120 degrees. In some embodiments, each second long line segment 322 substantially extends along the length direction D1. In some other embodiments, the second short line segment 321 is a straight line, an arc, or a curve. In other embodiments, the second long line segment 322 is a straight line, an arc, or a curve. In some embodiments, the number of the above-mentioned "second long line segments 322" is an even number, such as 2, 4, 6, 8 or more, and this technical feature provides excellent technical effects, refer to the above description of the embodiment of the first long line segment 212.

[0070] In other embodiments, the first meandering radiating element 210 and the second meandering radiating element 320 are mirror images of each other. In some embodiments, the first meandering strip width W1 and the second meandering strip width W2 are respectively about 20% to about 30% of the length L4 of the connecting portion 110 .

[0071] In some other embodiments, the antenna radiating element 100 further includes a first radiating block 510 and a second radiating block 512. The first radiating block 510 extends from the end 214 of the first meandering radiating element 210, and the second radiating block 512 extends from the end 324 of the second meandering radiating element 320. The first radiating block 510 and the second radiating block 512 provide additional capacitance effect for the antenna radiating element 100, which helps to expand the bandwidth of the wireless radio frequency identification tag. In some embodiments, the length direction D2 of the first radiating block 510 and the length direction D3 of the second radiating block 512 are substantially parallel to the length direction D1 of the connecting portion 110, the length L1 of the first radiating block 510 is greater than or equal to the first meandering band width W1, and the length L2 of the second radiating block 512 is greater than or equal to the second meandering band width W2. In some embodiments, the spacing G1 between the first radiation block 510 and the second radiation block 512 is about 1 mm to about 12 mm, for example, about 1 mm, about 2 mm, about 4 mm, about 6 mm, about 8 mm, about 10 mm, or about 12 mm. In some embodiments, when the spacing G1 is less than a certain value, such as about 1 mm, a higher precision process may be required to avoid a short circuit between the two, thereby increasing the manufacturing cost. However, in other embodiments, when the spacing G1 is greater than a certain value, such as about 12 mm, the effect of the first radiation block 510 and the second radiation block 512 in providing additional capacitance is not significant.

[0072] The loop antenna 400 is located between the first meandering radiating element 210 and the second meandering radiating element 320, and there is no conductive connection between the loop antenna 400 and the antenna radiating element 100. The above "there is no conductive connection between the loop antenna 400 and the antenna radiating element 100" means that the two are not directly connected or not connected via any conductor, but the loop antenna 400 is still electrically coupled to the antenna radiating element 100. This feature and / or other features of this feature work together to provide a specific technical effect. Specifically, this coupling feeding method can produce an imaginary part of inductance. By adjusting the distance between the loop antenna and the radiating element and the size of the loop antenna, the impedance and coupling strength of the antenna can be flexibly adjusted, thereby achieving better impedance matching characteristics. In some comparative examples, the loop antenna 400 is directly connected to the antenna radiating element 100 (or called a T-type feeding structure). The imaginary impedance (Reactance) curve of the T-type feeding method in the high frequency band fluctuates greatly, and it is not easy to match with various chips. The comparative examples below will be described in more detail.

[0073] In some embodiments of the present invention, the loop antenna 400 includes a first portion 410 adjacent to the connection portion 110 and a second portion 420 away from the connection portion 110. The second portion 420 includes a first open end 431 and a second open end 432 opposite to each other, and the loop antenna 400 does not include other open ends except the first open end 431 and the second open end 432. The first open end 431 and the second open end 432 are configured to connect a chip having only one set of connection ports. In the prior art, a chip having two sets of independent differential antenna ports is usually used to achieve a nearly spherical radiation pattern, but the price of such a chip is relatively expensive. One of the features of the embodiments described in this paragraph is that by changing the structure of the antenna radiation element, a chip having only one set of connection ports can achieve a nearly spherical radiation pattern without using a chip having two sets of independent differential antenna ports. Please note that in other embodiments of the present invention, the loop antenna 400 may include more than two open ends to connect chips of different specifications to produce more diverse or other technical effects.

[0074] In other embodiments, the spacing G2 between the loop antenna 400 and the connecting portion 110 is about 0.2 mm to about 1 mm. In some embodiments, when the spacing G2 is less than a certain value, such as about 0.2 mm, the curve value of the imaginary impedance is generally high, which may cause poor impedance matching between the antenna and the chip in certain frequency ranges. In other embodiments, when the spacing G2 is greater than a certain value, such as about 1 mm, the imaginary impedance becomes smaller and shifts toward the low frequency direction, resulting in a reduction in the overall bandwidth and a decrease in radiation efficiency. Therefore, in some embodiments, the spacing G2 between the loop antenna 400 and the connecting portion 110 is about 0.2 mm to about 1 mm, for example, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, or about 1 mm. According to multiple embodiments, by adjusting the spacing G2, the wireless radio frequency identification tag can have good impedance matching and provide satisfactory radiation performance. However, in other implementations, the distance G2 between the loop antenna 400 and the connecting portion 110 may not be within the above numerical range.

[0075] Although Figure 1 The loop antenna 400 shown in the figure has a rectangular appearance, but in other embodiments, the appearance of the loop antenna 400 may be an ellipse, a circle, a polygon, or other shapes.

[0076] Figure 2FIG. 1 is a top view schematic diagram of an antenna 10B of a wireless RFID tag in certain other embodiments of the present invention. The antenna 10B of the wireless RFID tag includes an antenna radiating element 100 and a loop antenna 400. The antenna radiating element 100 of the antenna 10B of the wireless RFID tag can be, for example, the various embodiments described above with respect to the antenna 10A of the wireless RFID tag. Compared to Figure 1 The loop antenna 400 ″ shown in the figure further includes a first meandering portion 450 and a second meandering portion 460 .

[0077] In some embodiments, the first meandering portion 450 is adjacent to the first meandering radiating element 210, and the second meandering portion 460 is adjacent to the second meandering radiating element 320. In some embodiments, the minimum spacing between the first meandering portion 450 and the first meandering radiating element 210 and the minimum spacing between the second meandering portion 460 and the second meandering radiating element 320 are each about 0.5 mm to about 8 mm, such as about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, or about 8 mm. In some embodiments, when the above minimum spacing is less than a certain value, such as 0.5 mm, the coupling interference generated between the first meandering portion 450 and the first meandering radiating element 210 (and between the second meandering portion 460 and the second meandering radiating element 320) is relatively strong, which may be detrimental to the overall performance of the antenna 10B of the wireless radio frequency identification tag. In other embodiments, when the minimum spacing is greater than a certain value, such as 8 mm, the sizes of the first meandering radiating element 210 and the second meandering radiating element 320 must be reduced while maintaining the same length and width of the overall antenna. This may cause the resonant frequency of the antenna 10B of the wireless radio frequency identification tag to shift to a higher frequency band.

[0078] In other embodiments, the first meandering portion 450 and the second meandering portion 460 are located on opposite sides of the loop antenna 400 ″. Figure 2 The first meandering portion 450 and the second meandering portion 460 are respectively located on the left and right sides of the loop antenna 400", but in other embodiments, the first meandering portion 450 and the second meandering portion 460 can be respectively located on the upper and lower sides of the loop antenna 400". In some other embodiments, the meandering tape axis A3 of the first meandering tape axis 450 is substantially parallel to the first meandering tape axis A1, and the meandering tape axis A4 of the second meandering tape axis 460 is substantially parallel to the second meandering tape axis A2. However, in other embodiments, various performances of the wireless radio frequency identification tag, such as impedance matching with the chip or operable bandwidth, can be adjusted by adjusting the position, angle, and size of the meandering tape axis A3 and / or the meandering tape axis A4.

[0079] In some other embodiments, the loop antenna 400" has an axial length L3, and the axial length L3 is defined as the length measured parallel to the length direction D1. In some embodiments, the axial length L3 is less than the length L4 of the connecting portion 110, and the meandering band width 450W of the first meandering portion 450 and the meandering band width 460W of the second meandering portion 460 are respectively less than half of the axial length L3 of the loop antenna 400". In some embodiments, the meandering band width 450W of the first meandering portion 450 and the meandering band width 460W of the second meandering portion 460 are respectively about 0.5 mm to about 9 mm, for example, about 0.5 mm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, or about 9 mm. In some embodiments, when the meandering band width 450W and the meandering band width 460W are respectively less than a certain value, for example, 0.5 mm, the imaginary impedance and the real impedance are too high, resulting in poor matching between the antenna and certain chips. In other embodiments, when the meandering band width 450W and the meandering band width 460W are respectively greater than a certain value, such as 9 mm, the imaginary impedance and the real impedance are both reduced, which helps to improve the matching degree between the antenna and certain chips, but may lead to reduced sensitivity in the high frequency range. According to the above embodiment, the matching degree and sensitivity between the tag antenna and the chip can be optimized by adjusting the meandering band width 450W and the meandering band width 460W.

[0080] Figure 3 The antenna sensitivity of the first meandering portion 450 and the second meandering portion 460 at three different meandering band widths is measured using a "Tagformance" device in some embodiments of the present invention, wherein the meandering band widths of the first meandering portion 450 and the second meandering portion 460 are both 0 mm (similar to Figure 1 embodiment shown), 4 mm, and 8 mm. Figure 3 The vertical axis P represents the "Power of tag forward". Figure 3 It can be observed that when the meandering band width is 0mm, the sensitivity bandwidth is larger. When the meandering band width increases, although the resonance frequency in the high-frequency range moves unfavorably toward the low-frequency direction, it is found in the simulation results of the antenna impedance that increasing the meandering band width is beneficial to improving the matching between the antenna and the chip. Therefore, by adjusting the size of the meandering band width, not only can the sensitivity bandwidth of the tag antenna be flexibly adjusted, but the impedance curve can also be optimized to achieve applications with specific performance requirements.

[0081] Figure 4 FIG. 1 is a top view of an antenna 10C of a radio frequency identification tag according to Comparative Example 1 of the present invention. For the purpose of simplicity, only the antenna 10C and the Figure 2The main differences of the antenna 10B are shown in that the first meandering zone axis C1 of the first meandering radiating element 210C and the second meandering zone axis C2 of the second meandering radiating element 320C of the antenna 10C are substantially parallel to the length direction D1 of the connecting portion 110 . Figure 5 The radiation pattern simulation result of the antenna 10C of Comparative Example 1 at 920 MHz is shown in FIG. Figure 6 The radiation pattern simulation results of antenna 10B at 920MHz in some embodiments of the present invention are shown in FIG. Figure 5 and Figure 6 In the example, the angle value "0" is Figure 1 , Figure 2 ,and Figure 4 The direction x shown in the figure has an angle value of "90" Figure 1 , Figure 2 ,and Figure 4 The direction y is shown in the figure. Figure 5 In the y direction, the radiation intensity is significantly lower than that in other directions. Figure 6 In the y direction, the radiation intensity is significantly improved. In addition, compared with Figure 4 The antenna 10C shown in FIG. 1 is a schematic diagram of an antenna 10C according to some embodiments of the present invention (eg Figure 2 The antenna 10B is shown, which can effectively reduce the size of the antenna.

[0082] Figure 7 FIG. 1 is a top view of an antenna 10D of a radio frequency identification tag according to Comparative Example 2 of the present invention. For the purpose of simplicity, only the antenna 10D and the Figure 2 The main differences of the illustrated antenna 10B. The loop antenna 400D of the antenna 10D is directly connected to the connecting portion 110 (or integrated into one body). The first open end 431 and the second open end 432 of the loop antenna 400D are used to connect the chip, so the chip signal is transmitted to the connecting portion 110 via the conductor. This connection method is called "T-type feeding" in the technical field to which the present invention belongs. According to the results of "Ansys HFSS" simulating the reflection coefficient and power transmission coefficient of the antenna 10D in the frequency range of 800-1000MHz, the antenna 10D only has a resonant frequency point at a frequency of 855MHz. On the contrary, Figure 2 The antenna 10B shown in the figure has two resonant frequency points at 865 MHz and 947 MHz. Figure 2 The antenna 10B shown is more suitable for applications with a wide frequency range, for example, it has good sensitivity in both the European and American frequency ranges. Furthermore, according to the simulation results of the antenna impedance, the imaginary impedance curve of the feeding method of the antenna 10D fluctuates greatly in the high frequency band, making it difficult to match the chip. Figure 2 The imaginary impedance curve of the antenna 10B shown matches the chip well. In addition, according to the simulation results of sensitivity, Figure 2The sensitivity of the antenna 10B is shown to be lower than -10 dBm, which is significantly better than the sensitivity performance of the antenna 10D.

[0083] In addition to the above technical effects or advantages, in some embodiments, when the radio frequency identification tag of the present invention is attached to a carton, the radio frequency identification tag can work normally.

[0084] The above discloses multiple embodiments (or examples) of the present invention and related technical effects. Different embodiments or examples have different or the same technical effects. Therefore, any embodiment (or example) of the present invention or the scope of the patent application does not need to achieve all the purposes, advantages, or technical effects disclosed by the present invention. In addition, the different embodiments and / or examples described herein can be combined with each other in beneficial situations without additional explanation. Therefore, the embodiments of the present invention include combinations of the above-mentioned various embodiments and / or examples in beneficial situations.

Claims

1. An antenna for a radio frequency identification tag, characterized in that: Include: Antenna radiating element, comprising: A connecting portion, comprising a first end and a second end, and the connecting portion has a length direction; A first meandering radiation element extending from the first end of the connecting portion, the first meandering radiation element having a first meandering belt axis, and the first meandering belt axis is not parallel to the length direction; as well as A second meandering radiation element extending from the second end of the connecting portion, the second meandering radiation element having a second meandering belt axis, and the second meandering belt axis is not parallel to the length direction; as well as The loop antenna is located between the first meandering radiating element and the second meandering radiating element, and there is no conductive body connecting the loop antenna and the antenna radiating elements.

2. The antenna of a radio frequency identification tag according to claim 1, characterized in that: The first meandering belt axis and the second meandering belt axis are substantially perpendicular to the length direction.

3. The antenna of a radio frequency identification tag according to claim 1, characterized in that: The loop antenna includes a first portion adjacent to the connecting portion and a second portion away from the connecting portion, the second portion includes a first open end and a second open end opposite to each other, and the loop antenna does not include other open ends except the first open end and the second open end.

4. The antenna of a wireless radio frequency identification tag according to claim 1 or 3, characterized in that: The loop antenna further includes a first meandering portion and a second meandering portion, wherein the second meandering portion is opposite to the first meandering portion.

5. The antenna of a radio frequency identification tag according to claim 4, characterized in that: The loop antenna has an axial length substantially parallel to the length direction, and a meandering width of each of the first meandering portion and the second meandering portion is less than half of the axial length of the loop antenna.

6. The antenna of a radio frequency identification tag according to claim 5, characterized in that: The axial length is smaller than a length of the connecting portion.

7. The antenna of a radio frequency identification tag according to claim 4, characterized in that: The meandering belt axis of the first meandering portion is substantially parallel to the first meandering belt axis, and the meandering belt axis of the second meandering portion is substantially parallel to the second meandering belt axis.

8. The antenna of a wireless radio frequency identification tag according to claim 1, characterized in that: The antenna radiating element further includes a first radiating block and a second radiating block, wherein the first radiating block extends from an end of the first meandering radiating element, and the second radiating block extends from an end of the second meandering radiating element.

9. The antenna of a radio frequency identification tag according to claim 8, characterized in that: The length direction of the first radiation block and the length direction of the second radiation block are substantially parallel to the length direction of the connecting portion.

10. The antenna of a wireless radio frequency identification tag according to claim 8, characterized in that: The first meandering radiation element and the second meandering radiation element have a first meandering band width and a second meandering band width respectively, the length of the first radiation block is greater than or equal to the first meandering band width, the length of the second radiation block is greater than or equal to the second meandering band width, and the spacing between the first radiation block and the second radiation block is 1mm to 12mm.

11. The antenna of a radio frequency identification tag according to claim 1, characterized in that: The first meandering radiation element includes a plurality of first short line segments and a plurality of first long line segments that are alternately arranged and connected, the starter of each of the first short line segments extends from the first end, each of the first short line segments is not parallel to each of the first long line segments, and the number of each of the first long line segments is an even number, and the second meandering radiation element includes a plurality of second short line segments and a plurality of second long line segments that are alternately arranged and connected, the starter of each of the second short line segments extends from the second end, each of the second short line segments is not parallel to each of the second long line segments, and the number of each of the second long line segments is an even number.

12. The antenna of a radio frequency identification tag according to claim 1, characterized in that: The first meandering radiating element and the second meandering radiating element are mirror-symmetrical to each other.

13. The antenna of a radio frequency identification tag according to claim 1, characterized in that: The distance between the loop antenna and the connecting portion is 0.2 mm to 1 mm.

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