An anti-metal tag

Abstract

This utility model relates to an anti-metal tag, comprising: an upper radiating surface, an intermediate dielectric layer, a bottom grounding layer connected to the upper radiating surface, and a chip; the upper radiating surface includes a centrally located hollow rectangular sheet; a U-shaped matching groove located around the rectangular sheet; and an L-shaped tuning loading; the chip is disposed between the rectangular sheet and the matching groove. The upper radiating surface, through modular design (main radiator + matching structure + tuning structure), can be independently optimized for radiation efficiency, impedance matching, and frequency stability, ultimately achieving long-distance, highly reliable identification in metallic environments. It is an ultra-thin, small-sized, and highly anti-metal flexible tag structure.

Description

Technical Field

[0001] This utility model relates to the fields of RFID tag antennas and RFID communication, and in particular to an anti-metal tag. Background Technology

[0002] RFID technology is a non-contact automatic identification technology. In recent years, with the rapid development of the Internet of Things (IoT) industry, RFID technology, as an important supporting technology for IoT, has also developed rapidly and is widely used in warehouse management, item tracking and positioning, anti-counterfeiting supervision of pharmaceuticals, and traffic vehicle management.

[0003] With the development and application of RFID technology, RFID asset management is widely used in various fields. In the management of heavy assets and tools, various metallic environments are inevitably encountered. Conventional tags are limited by traditional dipole antennas, and such environments have a significant impact on tag performance. Furthermore, conventional anti-metal tags are thicker than 1mm, resulting in an unsightly appearance when used on metal surfaces. Therefore, there is an urgent need to design a lightweight, small-sized anti-metal tag to address issues such as: the thickness of conventional flexible anti-metal tags on metal surfaces; the excessive weight of ordinary PCB anti-metal tags; the stringent environmental requirements for ordinary anti-metal tags; the problem of excessively large size of PCB anti-metal tags with the same performance; and the near absence of ultra-thin anti-metal tags on the market. Utility Model Content

[0004] To solve at least one of the above-mentioned technical problems, this utility model provides an anti-metal tag, comprising: an upper radiating surface, an intermediate dielectric layer, a bottom grounding layer connected to the upper radiating surface, and a chip;

[0005] The upper radiating surface includes a hollow rectangular plate set in the center; a U-shaped matching groove located around the rectangular plate; and an L-shaped tuning load;

[0006] The chip is positioned between the rectangular plate and the matching slot.

[0007] Furthermore, the cutout rectangular piece is rectangular, and its length and width are determined according to the inductance value of the required inductor ring and / or the fundamental resonant frequency of the tag antenna; the cutout ratio of the cutout rectangular piece is determined according to the required equivalent inductance and capacitance.

[0008] Furthermore, the U-shaped matching grooves are symmetrically distributed around the periphery of the rectangular piece, and the openings face the short side of the hollowed-out rectangular piece.

[0009] Furthermore, the width of the U-shaped matching groove is greater than the width of the hollow rectangular piece, and the depth is less than the length of the hollow rectangular piece.

[0010] Furthermore, the L-shaped tuning load includes a first branch and a second branch located at the top and bottom; the first branch is obliquely connected to the upper edge of the upper radiating surface; the second branch is vertically connected to the lower edge of the upper radiating surface and connected to the hollow rectangular plate.

[0011] Furthermore, the intermediate dielectric layer is a foam dielectric layer with a thickness of 0.2-0.5mm.

[0012] Furthermore, the bottom ground layer is linked to the upper radiating surface and is etched as a whole during the production process. The upper radiating surface and the bottom ground layer are placed on the upper and lower sides of the intermediate dielectric layer by wrapping.

[0013] Furthermore, the chip's equivalent RC is 2500Ω, with a parallel connection of 1.045pF.

[0014] This invention provides an anti-metal tag, comprising: an upper radiating surface, an intermediate dielectric layer, a bottom grounding layer connected to the upper radiating surface, and a chip; the upper radiating surface includes a centrally located hollow rectangular sheet; a U-shaped matching groove located around the rectangular sheet; and an L-shaped tuning loading; the chip is disposed between the rectangular sheet and the matching groove. The upper radiating surface, through modular design (main radiator + matching structure + tuning structure), can be independently optimized for radiation efficiency, impedance matching, and frequency stability, ultimately achieving long-distance, highly reliable identification in metallic environments. It is an ultra-thin, small-sized, and highly anti-metal flexible tag structure. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of one embodiment of the anti-metal tag of this utility model;

[0016] Figure 2 This is a schematic diagram of the resonant frequency of the anti-metal tag of this utility model;

[0017] Figure 3 This is a schematic diagram showing the overall efficiency and omnidirectional radiation efficiency of the anti-metal tag of this utility model;

[0018] Figure 4 This is a schematic diagram illustrating the actual efficiency of the anti-metal label of this utility model when it is simulated and affixed to a cigarette box. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] It should be noted that if any directional indication, such as up, down, left, right, front, back, etc., is involved in the embodiments of this utility model, such directional indication is only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. Furthermore, if any description involving "first," "second," "S1," "S2," "step one," "step two," etc., is involved in the embodiments of this utility model, such description is only for descriptive purposes and should not be construed as indicating or implying their relative importance, or implicitly indicating the number of technical features indicated or the execution order of the method. Those skilled in the art will understand that anything that does not violate the essential points of the utility model within the scope of its inventive concept should be included within the protection scope of this utility model.

[0021] like Figure 1 As shown, this utility model provides an anti-metal tag, including: an upper radiating surface 1, an intermediate dielectric layer 2, a bottom grounding layer 3 connected to the upper radiating surface, and a chip 4;

[0022] The upper radiating surface includes a hollow rectangular plate 11 set in the center; a U-shaped matching groove 12 located around the rectangular plate; and an L-shaped tuning load 13.

[0023] The chip is positioned between the rectangular plate and the matching slot.

[0024] This embodiment presents an anti-metal tag of the present invention. 1. The upper radiating surface, serving as the tag's "antenna radiator," is responsible for receiving and transmitting radio waves (for communication with the reader). It adopts a cut-out design, including a central cut-out rectangular piece, a U-shaped matching groove around the rectangular piece, and an L-shaped tuning load, forming a cut-out radiating surface. The equivalent impedance of the radiator is adjusted by the cut-out rectangular pattern to match the impedance of the tag chip (typically 50Ω), reducing signal reflection and improving energy transmission efficiency; it also increases the electrical length; and the inductance value of the formed inductor ring can be adjusted by adjusting the length and width of the cut-out rectangular piece. The rectangular piece, the U-shaped matching groove around the rectangular piece, and the L-shaped tuning load, combined, can change the current path length of the radiator, thereby adjusting the tag's resonant frequency (e.g., 860-960MHz in the UHF band), ensuring operation in the target frequency band even in a metallic environment. 2. The middle dielectric layer isolates the upper radiating surface from the lower ground layer (or metal carrier), serving as a crucial "isolation barrier" for anti-metal performance. Adjusting its material and thickness influences the antenna's resonant frequency and size. This dielectric layer prevents direct contact between the upper radiating surface and the metal carrier, avoiding the "short-circuit effect" of the metal on the radiator. Simultaneously, the dielectric properties adjust the antenna's equivalent wavelength, ensuring effective electromagnetic wave radiation. 3. The ground layer, connected to the upper layer, provides a "grounding reference plane," counteracting the negative impact of the metal carrier on electromagnetic waves and enhancing radiation efficiency. When the tag is affixed to a metal surface, the metal carrier can be considered an extension of the ground layer. The radiating surface and the ground layer (plus the metal carrier) form a structure similar to a "microstrip antenna," allowing electromagnetic waves to radiate through the gap between them, preventing direct absorption by the metal. The ground layer reflects electromagnetic waves leaking from the radiating surface, refocusing them in the radiation direction and enhancing signal strength.

[0025] The upper radiating surface, through a modular design (main radiator + matching structure + tuning structure), can be independently optimized for radiation efficiency, impedance matching, and frequency stability, ultimately achieving long-distance, high-reliability identification in metallic environments. Specifically:

[0026] 1. A hollowed-out rectangular plate serves as the main radiator of the antenna, undertaking most of the signal transmission and reception functions. The unhollowed-out frame forms the main current path. Preferably, the hollowed-out rectangular plate is rectangular, and its length and width are determined based on the required inductance value of the inductor ring and / or the fundamental resonant frequency of the tag antenna, directly affecting the fundamental resonant frequency of the antenna (approximately half-wavelength or quarter-wavelength structure). More preferably, the hollowing-out ratio (hollowing-out area / total area of ​​the rectangular plate) is determined based on the required equivalent inductance and capacitance. Larger hollowing-out areas increase the equivalent inductance and decrease the capacitance, which can be used for fine-tuning the resonant point. This rectangular plate structure can form a stable electromagnetic field distribution above the grounding layer (or metal carrier), reducing the scattering interference of the metal on the signal.

[0027] 2. The peripheral U-shaped matching slot, achieving impedance matching between the antenna and the chip, is a key structure for improving energy transmission efficiency. Preferably, the U-shaped matching slots are symmetrically distributed around the periphery of the rectangular plate, with the opening facing the short side of the hollowed-out rectangular plate. The width is greater than the width of the hollowed-out rectangular plate, and the depth is less than the length of the hollowed-out rectangular plate. This matching slot structure: on the one hand, the symmetrical distribution avoids interference with the current path of the main radiator, and at the same time, it finely adjusts the bulk impedance through the edge coupling effect. On the other hand, it is equivalent to a "tunable LC network": the depth, width, and opening size of the slot determine the values ​​of the equivalent capacitance and inductance. By adjusting the parameters of the U-shaped slot, the input impedance of the antenna (which may exhibit high reactance in a metallic environment) can be adjusted to match the impedance of the tag chip (usually a 50Ω pure resistance or a specific complex impedance), minimizing signal reflection.

[0028] 3. The L-shaped tuned loading allows for fine-tuning of the antenna's resonant frequency and bandwidth, enhancing frequency stability in anti-metal environments. The L-shaped tuned loading includes a first branch and a second branch located vertically. The first branch is angled and connected to the upper edge of the upper radiating surface; the second branch is vertically connected to the lower edge of the upper radiating surface and connected to the hollowed-out rectangular plate. This L-shaped tuned loading increases the current path length, equivalent to "extending the antenna's electrical size," lowering the resonant frequency without increasing the physical size, thus reducing the overall tag size and making it suitable for miniaturized designs. The two-branch structure forms a balanced structure, counteracting asymmetric electromagnetic interference from the metal carrier, widening the operating bandwidth, and reducing the impact of frequency offset on readout performance.

[0029] The three work together:

[0030] Basic radiation: The central hollow rectangular plate serves as the main radiator, forming a basic resonant circuit above the metal grounding layer, generating the main radiation field.

[0031] Impedance matching: The U-shaped matching slot adjusts the overall impedance through edge coupling, enabling the antenna and chip to transmit energy efficiently (reducing the VSWR).

[0032] Frequency stability: L-shaped tuning load compensates for frequency shifts caused by the metallic environment, while widening the bandwidth to ensure stable operation on metal carriers of different thicknesses and materials.

[0033] In summary, the core of this anti-metal tag is the use of a combination of "grounding layer + dielectric layer + radiating surface" to transform the metal carrier from an "interference source" into an "auxiliary radiator." When the tag is attached to a metal surface, the metal carrier and the grounding layer together form a stable grounding plane. The upper radiating surface adjusts the impedance through a hollow design to match the chip. The dielectric layer isolates the radiating surface from the grounding layer, controlling the coupling strength of electromagnetic waves between them, allowing the tag to resonate and radiate signals even in a metal environment. Advantages: It can be directly attached to metal surfaces (such as steel pipes, equipment, and metal packaging), has a reading distance of several meters (greater than 4 meters in the UHF band), adapts to harsh environments (waterproof, resistant to high and low temperatures), and is an ultra-thin (<0.5mm), small-sized tag structure with strong anti-metal capabilities. Applications: Industrial asset management (metal tools, equipment, molds); logistics and supply chain (metal containers, steel coils, automotive parts); power and infrastructure (cable, pipe, tower markings), etc.

[0034] More preferably, the intermediate dielectric layer is a foam dielectric layer with a thickness of 0.2-0.5 mm; preferably 0.4 mm. The specific thickness can be arbitrarily set according to the operating frequency and the metal environment. Too thin a layer may cause excessive coupling between the radiating surface and the grounding layer (or metal carrier), changing the impedance; too thick a layer may reduce the radiation efficiency.

[0035] More preferably, the bottom ground layer is linked to the upper radiating surface and is etched as a whole during the production process. The upper radiating surface and the bottom ground layer are placed on the upper and lower sides of the intermediate dielectric layer by wrapping.

[0036] More preferably, the chip has an equivalent RC of 2500Ω and a parallel connection of 1.045pF. Preferably, the Yingxin C899 chip is used.

[0037] Beneficial effects:

[0038] Low thickness, no bumps or marks after use.

[0039] Low cost and easy to process. Can be produced on a standard flexible anti-metal label production line.

[0040] High gain, high efficiency, and long read / write distance. Up to 4m with handheld devices; simulated antenna gain -7dB.

[0041] It has good matching, and the omnidirectional total efficiency and radiation efficiency are quite close, about -9dB.

[0042] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An anti-metal tag, characterized in that, include: The upper radiating surface, the middle dielectric layer, the bottom ground layer connected to the upper radiating surface, and the chip; The upper radiating surface includes a hollow rectangular plate set in the center; The U-shaped matching groove located on the periphery of the rectangular plate; and the L-shaped tuning load; The chip is positioned between the rectangular plate and the matching slot.

2. The anti-metal tag of claim 1, wherein, The cutout rectangular piece is rectangular, and its length and width are determined according to the inductance value of the required inductor ring and / or the fundamental resonant frequency of the tag antenna; the cutout ratio of the cutout rectangular piece is determined according to the required equivalent inductance and capacitance.

3. The anti-metal tag of claim 2, wherein, U-shaped matching grooves are symmetrically distributed around the periphery of the rectangular piece, with their openings facing the short side of the hollowed-out rectangular piece.

4. The anti-metal tag of claim 3, wherein, The width of the U-shaped matching groove is greater than the width of the hollow rectangular piece, and the depth is less than the length of the hollow rectangular piece.

5. The anti-metal tag of claim 4, wherein, The L-shaped tuning load includes a first branch and a second branch located at the top and bottom; the first branch is obliquely connected to the upper edge of the upper radiating surface; the second branch is vertically connected to the lower edge of the upper radiating surface and connected to the hollow rectangular plate.

6. The anti-metal tag of claim 5, wherein, The intermediate dielectric layer is made of foam dielectric with a thickness of 0.2-0.5mm.

7. The anti-metal tag of claim 6, wherein, The bottom ground layer is connected to the upper radiating surface. It is etched as a whole during the production process. The upper radiating surface and the bottom ground layer are placed on the upper and lower sides of the intermediate dielectric layer by wrapping.

8. The anti-metal tag of any one of claims 1-7, wherein, The chip's equivalent RC is 2500Ω, with a parallel connection of 1.045pF.

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