Antenna of radio frequency identification tag

Abstract

The utility model discloses an antenna of a wireless radio frequency identification tag. The antenna comprises an antenna radiation 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] This utility model relates to the field of product identification, specifically to an antenna for a radio frequency identification tag. Background Technology

[0002] In logistics management, RFID tag technology improves efficiency and reduces costs. However, existing RFID tags typically exhibit bidirectional radiation patterns, resulting in weaker radiation intensity perpendicular to the antenna, which limits their application. Furthermore, when RFID tags are attached to packaging boxes or other media, it can cause a shift in the entire operating frequency band or affect overall performance, posing a challenge in RFID tag design. Therefore, a more innovative RFID tag technology is urgently needed. Utility Model Content

[0003] One objective of this invention is to provide an antenna for a radio frequency identification (RFID) tag that can provide satisfactory radiation intensity in all directions.

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

[0005] Antenna radiating elements, including:

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

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

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

[0009] A loop antenna is located between the first meandering radiating element and the second meandering radiating element, and there is no conductive connection between the loop antenna and the antenna radiating element.

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

[0011] In some embodiments, the loop antenna includes a first portion adjacent to the connection portion and a second portion away from the connection portion, the second portion including a first open end and a second open end opposite to each other, and the loop antenna does not include any other open ends other than 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, the second meandering portion being 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 width of the meandering band of each of the first and second meandering portions is less than half of the axial length of the loop antenna.

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

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

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

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

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

[0019] In some embodiments, the first meandering radiating element comprises a plurality of alternating and connected first short segments and a plurality of first long segments, the initiator of each first short segment extending from the first end, each first short segment not parallel to each first long segment, and the number of each first long segment being even; and the second meandering radiating element comprises a plurality of alternating and connected second short segments and a plurality of second long segments, the initiator of each second short segment extending from the second end, each second short segment not parallel to each second long segment, and the number of each second long segment being even.

[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. Attached Figure Description

[0021] Figure 1 This is a top view schematic diagram of the antenna of the radio frequency identification tag in some embodiments of this utility model.

[0022] Figure 2 This is a top view schematic diagram of the antenna of the radio frequency identification tag in some other embodiments of this utility model.

[0023] Figure 3 The results of measuring the antenna sensitivity of the first and second bends at different bend widths using the "Tagformance" device in some embodiments of this utility model.

[0024] Figure 4 This is a top view schematic diagram of the antenna of the radio frequency identification tag of Comparative Example 1 of this utility model.

[0025] Figure 5 The simulation results of the radiation field pattern of antenna 10C in Comparative Example 1 at 920MHz are shown.

[0026] Figure 6 The above are simulation results of the antenna's radiation field pattern at 920MHz in some embodiments of this utility model.

[0027] Figure 7 This is a top view schematic diagram of the antenna of the radio frequency identification tag in Comparative Example 2 of this utility model. Explanation of main reference numerals:

[0028] 10A, 10B, 10C, 10D: Antennas for Radio Frequency Identification (RFID) Tags

[0029] 100: Antenna radiating element

[0030] 110: Connecting part

[0031] 111: First end

[0032] 112: Second end

[0033] 210, 210C: First meandering radiating element

[0034] 211: First short segment

[0035] 212: First Long Segment

[0036] 214: End

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

[0038] 321: Second short segment

[0039] 322: The second longest line segment

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

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

[0042] 410: Part One

[0043] 420: Part Two

[0044] 431: First Open Terminal

[0045] 432: Second Open Terminal

[0046] 450: First winding section

[0047] 450W, 460W: Width of the meandering band

[0048] 460: Second winding section

[0049] 510: First Radiation Block

[0050] 512: Second Radiation Block

[0051] A1, C1: First winding belt axis

[0052] A2, C2: Second winding belt axis

[0053] A3, A4: Winding with a shaft

[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 zone

[0059] W2: Width of the second meandering zone

[0060] x, y: direction; Detailed Implementation

[0061] Figure 1This is a top view schematic diagram of the antenna 10A of a radio frequency identification (RFID) tag in some embodiments of the present invention. The antenna 10A of the RFID 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.

[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, which may also be referred to as the 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 external outline of the connecting portion 110 may be elliptical, wedge-shaped, symmetrical double wedge-shaped, 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 may be located in the middle portion or other positions of the connecting portion 110.

[0063] The first meandering radiating element 210 extends from the first end 111 of the connecting portion 110. Specifically, the first meandering radiating element 210 meanders along a planar strip-shaped region, having a first meandering belt width W1 and a first meandering belt axis A1. The first meandering radiating element 210 bends at its outermost edges on both sides of the "first meandering belt," which is generally the entire strip-shaped region occupied by the bend of the first meandering radiating element 210. 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 centerline drawn based on the first meandering belt. The first meandering radiating element 210 extends laterally and laterally, generally with the first meandering belt axis A1 as its centerline. The definitions and descriptions of "meandering belt" and "meander-belt axis" in geographical science can be applied similarly or analogously to explain the "meandering belt" and "meander-belt axis" described herein.

[0064] In some embodiments, the first meandering belt axis A1 is essentially a straight line, but in other embodiments, the first meandering belt axis A1 is a polyline composed of multiple straight lines connected together, such as a simple polyline or a monotonous polyline, or the first meandering belt axis A1 may be a curve.

[0065] In some embodiments, the first meandering radiating element 210 includes a plurality of alternating and connected first short segments 211 and a plurality of first long segments 212. One of these first short segments 211 (e.g., the initial first short segment 211) extends directly from the first end 111, and each first short segment 211 is not parallel to each first long segment 212. In some embodiments, each first short segment 211 forms an angle of about 60 degrees to about 120 degrees with the connected first long segment 212, for example, 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 segment 212 extends substantially along the length direction D1. In still other embodiments, the length of the first long segment 212 substantially defines the width W1 of the first meandering band, and the length of each first long segment 212 is about 6 mm to about 16 mm, and the length of each first short segment 211 is about 0.2 mm to about 3 mm. In some other embodiments, each of the first short line segments 211 is substantially a straight line, an arc, or a curve. In other embodiments, each of the first long line segments 212 is substantially a straight line, an arc, or a curve.

[0066] In some embodiments, the number of 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 "↓" illustrate the current flow obtained from computer simulation software (Ansys HFSS). When each of the first long segments 212 extends substantially along the x-direction, the current distribution of an even number of first long segments 212 in the x-direction cancels each other out during far-field radiation. However, the first short segments 211 can still provide effective radiation in the vertical y-direction (direction y is perpendicular to direction x). Therefore, this design can improve the radiation intensity of the RFID tag in the y-direction (i.e., the vertical direction), thus contributing to a near-spherical radiation pattern.

[0067] The second meandering radiating element 320 extends from the second end 112 of the connecting portion 110. The second meandering radiating element 320 has a second meandering band axis A2 and a second meandering band width W2. The meanings of the second meandering band, the second meandering band width W2, and the second meandering band axis A2 are explained above in the description of the first meandering radiating element 210. In some embodiments, the second meandering band axis A2 is essentially a straight line, but in other embodiments, the second meandering band axis A2 is a broken line formed by connecting multiple straight lines, such as a simple broken line or a monotonous broken line, or the second meandering band axis A2 may be a curve.

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

[0069] In some embodiments, the second meandering radiating element 320 includes a plurality of alternately arranged and connected second short segments 321 and a plurality of second long segments 322. One of these second short segments 321 (the initial second short segment 321) extends directly from the second end 112, and each second short segment 321 is not parallel to each second long segment 322. In some embodiments, the second short segments 321 and the second long segments 322 form an angle of about 60 degrees to about 120 degrees, for example, 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 segment 322 extends substantially along the length direction D1. In still other embodiments, the second short segments 321 are straight lines, arcs, or curves. In other embodiments, the second long segments 322 are straight lines, arcs, or curves. In some embodiments, the number of the above-mentioned "second long line segment 322" is an even number, such as 2, 4, 6, 8 or more, and this technical feature provides excellent technical effects, as described above regarding 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 widths W1 and W2 of the first meandering strip are approximately 20% to approximately 30% of the length L4 of the connecting portion 110, respectively.

[0071] In some 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 to the antenna radiating element 100, which helps to extend the bandwidth of the 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 width W1 of the first meandering band, and the length L2 of the second radiating block 512 is greater than or equal to the width W2 of the second meandering band. In some embodiments, the distance G1 between the first radiating block 510 and the second radiating block 512 is approximately 1 mm to approximately 12 mm, for example, approximately 1 mm, approximately 2 mm, approximately 4 mm, approximately 6 mm, approximately 8 mm, approximately 10 mm, or approximately 12 mm. In some embodiments, when the distance G1 is less than a certain value, such as approximately 1 mm, a higher precision manufacturing process may be required to avoid short circuits between the two, thus increasing manufacturing costs. However, in other embodiments, when the distance G1 is greater than a certain value, such as approximately 12 mm, the effect of the first radiating block 510 and the second radiating 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 phrase "no conductive connection between the loop antenna 400 and the antenna radiating element 100" means that they are not directly connected or connected via any conductive material, 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 specific technical effects. Specifically, this coupling feed method can generate an imaginary part of inductance. By adjusting the distance between the loop antenna and the radiating element, as well as 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 referred to as a T-type feed structure). The T-type feed method exhibits larger fluctuations in the imaginary impedance (reactance) curve at high frequencies, making it difficult to match with various chips. The comparative examples below will describe this in more detail.

[0073] In some embodiments of this invention, the loop antenna 400 includes a first portion 410 adjacent to the connection portion 110 and a second portion 420 distant 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 any other open ends besides 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 to a chip with only one set of connection ports. In the prior art, chips with two sets of independent differential antenna ports are typically used to achieve an approximately spherical radiation pattern, but such chips are relatively expensive. One feature of the embodiments described in this paragraph is that by changing the structure of the antenna radiating element, a chip with only one set of connection ports can achieve an approximately spherical radiation pattern without using a chip with two sets of independent differential antenna ports. Note that in other embodiments of this invention, the loop antenna 400 may include more than two open ends to connect chips of different specifications to produce more variety or other technical effects.

[0074] In some embodiments, the distance G2 between the loop antenna 400 and the connection portion 110 is approximately 0.2 mm to approximately 1 mm. In some embodiments, when the distance G2 is less than a certain value, such as approximately 0.2 mm, the imaginary impedance curve value is generally high, which may lead to poor impedance matching between the antenna and the chip in certain frequency ranges. In other embodiments, when the distance G2 is greater than a certain value, such as approximately 1 mm, the imaginary impedance becomes smaller and shifts towards lower frequencies, resulting in a reduction in overall bandwidth and a decrease in radiation efficiency. Therefore, in some embodiments, the distance G2 between the loop antenna 400 and the connection portion 110 is approximately 0.2 mm to approximately 1 mm, for example, approximately 0.2 mm, approximately 0.3 mm, approximately 0.4 mm, approximately 0.5 mm, approximately 0.6 mm, approximately 0.7 mm, approximately 0.8 mm, approximately 0.9 mm, or approximately 1 mm. According to various embodiments, by adjusting the distance G2, the RFID tag can have good impedance matching and provide satisfactory radiation performance. However, in other embodiments, the distance G2 between the loop antenna 400 and the connecting portion 110 may not be within the above-mentioned numerical range.

[0075] Although Figure 1 The illustrated loop antenna 400 resembles a rectangular shape, but in other embodiments, the outline of the loop antenna 400 may be elliptical, circular, polygonal, or other shapes.

[0076] Figure 2This is a top view schematic diagram of the antenna 10B of a RFID tag in some other embodiments of the present invention. The antenna 10B of the RFID tag includes an antenna radiating element 100 and a loop antenna 400. The antenna radiating element 100 of the antenna 10B of the RFID tag can be, for example, the various embodiments described above regarding the antenna 10A of the RFID tag. Compared to... Figure 1 The illustrated loop antenna 400 also includes a first meandering portion 450 and a second meandering portion 460.

[0077] In some embodiments, the first bend 450 is adjacent to the first bend radiating element 210, and the second bend 460 is adjacent to the second bend radiating element 320. In some embodiments, the minimum spacing between the first bend 450 and the first bend radiating element 210 and the minimum spacing between the second bend 460 and the second bend radiating element 320 are each about 0.5 mm to about 8 mm, for example, 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 aforementioned minimum spacing is less than a certain value, such as 0.5 mm, the coupling interference generated between the first bend 450 and the first bend radiating element 210 (and between the second bend 460 and the second bend radiating element 320) is relatively strong, which may be detrimental to the overall performance of the antenna 10B of the radio frequency identification tag. In other embodiments, when the minimum spacing is greater than a certain value, such as 8 mm, the size of the first meandering radiating element 210 and the second meandering radiating element 320 must be reduced while maintaining the same overall antenna length and width. This may cause the resonant frequency of the RFID tag's antenna 10B 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”. Although Figure 2 The first bend 450 and the second bend 460 are located on the left and right sides of the loop antenna 400”, respectively. However, in other embodiments, the first bend 450 and the second bend 460 may be located on the upper and lower sides of the loop antenna 400”, respectively. In still other embodiments, the bend axis A3 of the first bend 450 is substantially parallel to the first bend axis A1, and the bend axis A4 of the second bend 460 is substantially parallel to the second bend axis A2. However, in other embodiments, various performance characteristics of the RFID tag, such as impedance matching with the chip or operating bandwidth, can be adjusted by adjusting the position, angle, and size of the bend axis A3 and / or the bend axis A4.

[0079] In some embodiments, the loop antenna 400” has an axial length L3, 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 bend width 450W of the first bend portion 450 and the bend width 460W of the second bend portion 460 are each less than half of the axial length L3 of the loop antenna 400”. In some embodiments, the bend width 450W of the first bend portion 450 and the bend width 460W of the second bend portion 460 are each about 0.5mm to about 9mm, for example, about 0.5mm, about 1mm, about 2mm, about 3mm, about 4mm, about 5mm, about 6mm, about 7mm, about 8mm, or about 9mm. In some embodiments, when the bend width 450W and the bend width 460W are each less than a certain value, for example, 0.5mm, the imaginary impedance and real impedance are too high, resulting in poor matching between the antenna and some chips. In other embodiments, when the widths of the meandering band 450W and 460W are both greater than a certain value, such as 9mm, both the imaginary and real impedances decrease. While this helps improve the matching degree between the antenna and certain chips, it may lead to a decrease in sensitivity in the high-frequency range. According to the above embodiments, the matching degree between the tag antenna and the chip, as well as the sensitivity, can be optimized by adjusting the widths of the meandering band 450W and 460W.

[0080] Figure 3 This invention relates to the results of measuring the antenna sensitivity of the first bend 450 and the second bend 460 under three different bend widths using a "Tagformance" device in some embodiments of the present invention, wherein the bend width of both the first bend 450 and the second bend 460 is 0 mm (similar to...). Figure 1 The illustrated implementation methods are 4mm and 8mm. Figure 3 The vertical axis P represents "Power of tag forward". Figure 3 It can be observed that when the bend width is 0mm, the sensitivity bandwidth is relatively large. While increasing the bend width unfavorably shifts the resonant frequency in the high-frequency range towards lower frequencies, simulations of antenna impedance show that increasing the bend width improves the matching between the antenna and the chip. Therefore, by adjusting the bend width, not only can the sensitivity bandwidth of the tag antenna be flexibly adjusted, but the impedance curve can also be optimized to achieve specific performance requirements for applications.

[0081] Figure 4 This is a top view of the antenna 10C of the radio frequency identification tag in Comparative Example 1 of this utility model. For the sake of simplicity, only the antenna 10C and... Figure 2The main differences of antenna 10B are illustrated. The first meandering axis C1 of the first meandering radiating element 210C and the second meandering axis C2 of the second meandering radiating element 320C of antenna 10C are substantially parallel to the length direction D1 of the connecting part 110. Figure 5 To compare the radiation pattern simulation results of antenna 10C in Example 1 at 920MHz, Figure 6 The above are simulation results of the radiation field pattern of antenna 10B in certain embodiments of this utility model at 920MHz. Figure 5 and Figure 6 In the middle, 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 diagram. Figure 5 In the image, the radiation intensity in direction y is significantly lower than that in other directions. Figure 6 In the middle, the radiation intensity in the y-direction was significantly improved. Furthermore, compared to... Figure 4 The illustrated antenna 10C is based on some embodiments of the present invention (e.g.) Figure 2 The diagram shows antenna 10B, which can effectively reduce the size of the antenna.

[0082] Figure 7 This is a top view of the antenna 10D of the radio frequency identification tag in Comparative Example 2 of this utility model. For the sake of simplicity, only the antenna 10D and... Figure 2 The main difference between the illustrated antenna 10B and the antenna 10D is that the loop antenna 400D of the antenna 10D is directly connected to (or integrated into) the connecting part 110. The first open end 431 and the second open end 432 of the loop antenna 400D are used to connect the chip. Therefore, the signal from the chip is transmitted to the connecting part 110 via a conductor. This connection method is referred to as the "T-feed" method in the technical field to which this utility model pertains. According to the reflection coefficient and power transmission coefficient results of the "Ansys HFSS" analog antenna 10D in the frequency range of 800-1000MHz, the antenna 10D only has a resonant frequency point at 855MHz. Conversely, Figure 2 The illustrated antenna 10B exhibits resonant frequency points at both 865MHz and 947MHz, which is clearly... Figure 2 The illustrated antenna 10B is more suitable for wideband applications, such as exhibiting good sensitivity across both European and American frequency ranges. Furthermore, based on antenna impedance simulations, the feeding method of antenna 10D shows significant fluctuations in its imaginary impedance curve at high frequencies, making it difficult to match with the chip. Conversely, [the following is a more accurate translation of the original text, but the provided excerpt is incomplete and requires further context]. Figure 2 The plotted imaginary impedance curve of antenna 10B matches well with the chip. Furthermore, based on the sensitivity simulation results, Figure 2 The sensitivity of antenna 10B shown in the figure is all below -10dBm, which is significantly better than the sensitivity performance of antenna 10D.

[0083] In addition to the aforementioned technical effects or advantages, in some embodiments, the RFID tag of this invention can function normally when it is affixed to a cardboard box.

[0084] The foregoing discloses multiple embodiments (or examples) of this utility model and their related technical effects. Different embodiments or examples have different or the same technical effects. Therefore, any embodiment (or example) or claim scope of this utility model does not need to achieve all the objectives, advantages, or technical effects disclosed in this utility model. Furthermore, the different embodiments and / or examples described herein can be combined with each other where advantageous, without further explanation. Therefore, the embodiments of this utility model include combinations of the various embodiments and / or examples described above where advantageous.

Claims

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

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

3. The antenna for a radio frequency identification tag as described in claim 1, characterized in that: The loop antenna includes a first portion adjacent to the connection portion and a second portion away from the connection 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 any other open ends other than the first open end and the second open end.

4. The antenna for a radio frequency identification tag as described in claim 1 or 3, characterized in that: The loop antenna further includes a first meandering portion and a second meandering portion, the second meandering portion being opposite to the first meandering portion.

5. The antenna for a radio frequency identification tag as described in claim 4, characterized in that: The loop antenna has an axial length substantially parallel to the length direction, and the width of the meandering band 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 for a radio frequency identification tag as described in claim 5, characterized in that: The axial length is less than the length of the connecting portion.

7. The antenna for a radio frequency identification tag as described in claim 4, characterized in that: The first meandering section's meandering axis is substantially parallel to the first meandering axis, and the second meandering section's meandering axis is substantially parallel to the second meandering axis.

8. The antenna for a radio frequency identification tag as described in claim 1, characterized in that: The antenna radiating element further includes a first radiating block and a second radiating block, the first radiating block extending from the end of the first meandering radiating element, and the second radiating block extending from the end of the second meandering radiating element.

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

10. The antenna for a radio frequency identification tag as described in claim 8, characterized in that: The first wavy radiating element and the second wavy radiating element have a first wavy band width and a second wavy band width, respectively. The length of the first radiating block is greater than or equal to the first wavy band width, the length of the second radiating block is greater than or equal to the second wavy band width, and the distance between the first radiating block and the second radiating block is 1 mm to 12 mm.

11. The antenna for a radio frequency identification tag as described in claim 1, characterized in that: The first meandering radiating element comprises a plurality of alternating and connected first short segments and a plurality of first long segments, wherein the initiator of each first short segment extends from the first end, each first short segment is not parallel to each first long segment, and the number of each first long segment is even. The second meandering radiating element comprises a plurality of alternating and connected second short segments and a plurality of second long segments, wherein the initiator of each second short segment extends from the second end, each second short segment is not parallel to each second long segment, and the number of each second long segment is even.

12. The antenna for a radio frequency identification tag as described in claim 1, characterized in that: The first meandering radiating element and the second meandering radiating element are mirror images of each other.

13. The antenna for a radio frequency identification tag as described in claim 1, characterized in that: The distance between the loop antenna and the connecting part is 0.2 mm to 1 mm.

Images