RFID antenna and ticket with non-uniform field strength

Abstract

The present invention discloses an RFID antenna and ticket card with non-uniform field strength, wherein the RFID antenna includes a flat PCB antenna, wherein the PCB antenna is provided with high-permeability ferrite in the central area above and / or below the PCB antenna, and low-permeability ferrite with a lower permeability than the high-permeability ferrite is provided on the outer side of the central area. The present invention uses materials of different sizes of magnetic permeability to guide magnetic lines of force and control the intensity of the magnetic field distribution, so that within a unit area, the token ticket card can obtain more magnetic field energy, thereby ensuring the antenna's reading success rate and reading effect for small tickets. Therefore, the present invention can meet the needs of small-area tickets while taking into account the reading of standard tickets.

Description

Technical Field

[0001] The invention belongs to the technical field of RFID antennas. Background Art

[0002] RFID contactless card technology is currently used in many industrial applications, and the vast majority utilize cards that comply with the 13.56 MHz frequency band of ISO 14443. With rising consumer spending and a growing demand for personalization, a wide variety of customized cards have emerged on the market. These compact cards, featuring diverse patterns and designs, are popular as pendants such as keychains. Because these cards are generally smaller, with an effective area only about one-quarter the size of regular tickets, they are referred to in the industry as tokens.

[0003] Token tickets and regular tickets work in the same way and are used in the same way. However, due to their relatively small size, RFID antennas designed for standard tickets are not able to effectively recognize them. This is evident in the significantly reduced effective swipe distance when using token tickets, and sometimes even inability to swipe properly. Summary of the Invention

[0004] In view of the defects of the existing technology, the technical problem to be solved by the present invention is to provide an RFID antenna and ticket card with non-uniform field strength, so that while taking into account the reading of standard tickets and cards, more magnetic field energy can be gathered in a small local area as much as possible to meet the use of small-area tickets and cards.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] On the one hand, an RFID antenna with non-uniform field strength is provided, comprising a flat PCB antenna, wherein the PCB antenna is provided with high-permeability ferrite in the central area above and / or below the PCB antenna, and low-permeability ferrite with a lower permeability than the high-permeability ferrite is provided outside the central area, wherein the permeabilities of the high-permeability ferrite and the low-permeability ferrite are between 20μ and 120μ, and the difference in permeability between the high-permeability ferrite and the low-permeability ferrite is greater than 10μ.

[0007] Preferably, the magnetic permeability of the high-permeability ferrite is higher than 80μ; and / or the magnetic permeability of the low-permeability ferrite is lower than 40μ.

[0008] Preferably, the PCB antenna has a circular body, the high permeability ferrite is circular and concentrically arranged with the circular body, and the low permeability ferrite is annular and concentrically arranged with the high permeability ferrite.

[0009] Preferably, the outer circle of the low magnetic permeability ferrite is aligned with the outer circle of the circular body.

[0010] Preferably, the coverage area of ​​the high permeability ferrite is 20-35% of the corresponding circular area of ​​the circular body.

[0011] Preferably, the high permeability ferrite and the low permeability ferrite have the same thickness.

[0012] Preferably, the high permeability ferrite and the low permeability ferrite are pasted on the PCB antenna.

[0013] On the other hand, a ticket is provided, which is provided with the RFID antenna with non-uniform field strength.

[0014] This invention adopts the above-mentioned technical solution, using materials of varying magnetic permeability to guide magnetic lines of force and control the intensity of the magnetic field distribution. The high-permeability ferrite in the center area concentrates more magnetic field strength, allowing tokens to receive more magnetic field energy per unit area, thereby ensuring the antenna's reading success rate and quality for small tickets.

[0015] Therefore, the present invention can meet the needs of using small-area tickets and cards while taking into account the reading of standard tickets and cards.

[0016] The specific technical solutions adopted by the present invention and the beneficial effects thereof will be disclosed in detail in the following specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0018] Figure 1 This is a schematic diagram of the decomposed structure of an RFID antenna with non-uniform field strength according to the present invention;

[0019] Figure 2 The figure is a comparison diagram of the magnetic field lines of force of a bare PCB antenna and an antenna with ferrite.

[0020] Figure 3 A diagram comparing the magnetic field lines covered by a small TOKEN ticket and a standard ticket;

[0021] In the figure: PCB antenna 1, high magnetic permeability ferrite 2, low magnetic permeability ferrite 3. DETAILED DESCRIPTION

[0022] The following is an explanation and description of the technical solutions of the embodiments of the present invention in conjunction with the drawings of the embodiments of the present invention. However, the following embodiments are only preferred embodiments of the present invention and are not exhaustive. Based on the embodiments in the implementation manner, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0023] Those skilled in the art will appreciate that, unless there is any conflict, the features in the following embodiments and implementations may be combined with each other.

[0024] Currently, conventional large antennas have a relatively short read / write range for token tickets and cards, and therefore cannot provide adequate read / write performance for both small token tickets and standard large cards. Therefore, ferrite materials are used to manually manipulate the RFID magnetic field strength. Specifically, a standard PCB antenna is fabricated and, aligned with the center, high-permeability ferrite is attached to the center area on the top and bottom sides of the PCB antenna, while low-permeability ferrite is attached to the outer edges of the center area.

[0025] Example 1

[0026] like Figure 1 As shown, an RFID antenna with non-uniform field strength is provided on a ticket card, comprising a flat PCB antenna 1, wherein the PCB antenna 1 is provided with high permeability ferrite 2 in the central area above and below the PCB antenna 1 and low permeability ferrite 3 outside the central area.

[0027] It is understandable that the high-permeability ferrite 2 and the low-permeability ferrite 3 may also be provided only on the upper side or the lower side respectively.

[0028] The advantage of arranging ferrites on both the top and bottom sides of the antenna board is that it can ensure that the magnetic field shapes on the upper and lower sides of the antenna board are not distorted, and the paths through which the magnetic fields pass are consistent in shape.

[0029] The PCB antenna is a conventional PCB antenna made from a substrate such as FR4. Low-permeability ferrite is made from a ferrite material with a lower magnetic field strength, while high-permeability ferrite is made from a ferrite material with a higher magnetic field strength. It is understandable that the permeabilities of high-permeability ferrite and low-permeability ferrite are relative. For example, in common ferrite materials such as RFCL03, RFCL05, RFCL10, and RFCL20, the permeabilities of high-permeability ferrite 2 and low-permeability ferrite 3 can be designed to be between 20 and 120 μm. Furthermore, the permeability difference between the high-permeability ferrite and the low-permeability ferrite must meet a certain value, for example, greater than 10 μm.

[0030] In this embodiment, the magnetic permeability of the low-permeability ferrite 3 is 40 μ or less, and the magnetic permeability of the high-permeability ferrite 2 is 80 μ or more.

[0031] Conventional PCB antennas typically have a centrally symmetrical shape, such as a circle or rectangle. In this embodiment, the PCB antenna has a circular body, the high-permeability ferrite 2 is circular and concentrically arranged with the circular body, and the low-permeability ferrite 3 is annular and concentrically arranged with the high-permeability ferrite. If the PCB antenna has a rectangular body, the high-permeability ferrite 2 would be rectangular, and the low-permeability ferrite 3 would be a rectangular ring. Other possible shapes can be inferred by analogy and are not detailed here.

[0032] To increase magnetic field strength and meet the required card swipe area, the area covered by the high-permeability ferrite can be adjusted according to actual needs, but should be maintained at 20-35% of the total area to prevent the actual card swipe area from being too small. Taking a circular PCB antenna as an example, the high-permeability ferrite coverage area should be 20-35% of the circular area corresponding to the circular body.

[0033] Furthermore, the outer circle of the low magnetic permeability ferrite is aligned with the outer circle of the circular body, and the high magnetic permeability ferrite and the low magnetic permeability ferrite have the same thickness.

[0034] It is understandable that the high permeability ferrite and the low permeability ferrite can be adhered to the PCB antenna using 3M glue or other non-electromagnetic sensitive glue.

[0035] like Figure 2 As shown in the figure, the magnetic field lines of force distribution diagram of the PCB bare board antenna is compared with the magnetic field lines of the antenna with ferrite (high magnetic permeability ferrite 2 and low magnetic permeability ferrite 3). From the side of the antenna, it can be seen that the high magnetic permeability ferrite part in the middle can gather more magnetic field strength, so that the token ticket can obtain more magnetic field energy per unit area, thereby ensuring the antenna's reading success rate and reading effect for small tickets.

[0036] A PCB antenna serves as the innermost ticket reader antenna. Circular high-permeability ferrites (2) and low-permeability ferrites (3) with varying magnetic permeabilities are mounted concentrically on the upper and lower surfaces of the PCB antenna, based on the actual size of the ticket. It's understood that subsequent instrument calibration and fine-tuning of the antenna board's resistance and capacitance parameters can optimize overall antenna performance.

[0037] Taking advantage of the fact that different magnetic permeability materials have different passing rates for magnetic induction lines, higher magnetic permeability materials are used in the central area to ensure that most of the magnetic field passes through the central area. This allows for stronger magnetic induction intensity to be obtained over a certain area even when facing small-area token cards, thereby ensuring the reliability of reading small-area cards. Standard-area cards, on the other hand, can be read more normally because they cover a large area of ​​magnetic lines of force. Schematic diagram of card coverage of magnetic lines of force is shown below. Figure 3 As shown in the figure, the magnetic lines of force are more densely distributed in the center area of ​​the ticket.

[0038] Usage scenarios:

[0039] In scenario 1, a standard ticket card is used to swipe the card. The ticket card can cover 40% of the antenna area and obtain about 60% of the field strength signal of the entire antenna, which intuitively shows that the card can be swiped normally.

[0040] In scenario 2, a TOKEN card is used to swipe the card. The card can cover 10% of the antenna area and obtain about 35% of the field strength signal of the entire antenna. Intuitively, the card can also be swiped normally.

[0041] Example 2

[0042] A ticket card is provided with an RFID antenna with a non-uniform field strength as described in Example 1. The ticket card is typically a token card and operates in the 13.56 MHz frequency band as specified in ISO 14443. Of course, it is understood that other types of tickets, such as standard tickets, may also be used.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art will understand that the present invention includes, but is not limited to, the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. An RFID antenna with non-uniform field strength, comprising a flat PCB antenna, characterized in that: The PCB antenna is provided with high-permeability ferrite in the central area above and / or below it, and low-permeability ferrite with a lower permeability than the high-permeability ferrite is provided outside the central area. The permeabilities of the high-permeability ferrite and the low-permeability ferrite are between 20μ and 120μ, and the difference in permeability between the high-permeability ferrite and the low-permeability ferrite is greater than 10μ. The area covered by the high-permeability ferrite accounts for 20-35% of the total area above or below the PCB antenna.

2. The RFID antenna with non-uniform field strength according to claim 1, characterized in that: The magnetic permeability of the high-permeability ferrite is higher than 80μ; and / or the magnetic permeability of the low-permeability ferrite is lower than 40μ.

3. The RFID antenna with non-uniform field strength according to claim 1, characterized in that: The PCB antenna has a circular body, the high magnetic permeability ferrite is circular and concentrically arranged with the circular body, and the low magnetic permeability ferrite is annular and concentrically arranged with the high magnetic permeability ferrite.

4. The RFID antenna with non-uniform field strength according to claim 3, characterized in that: The outer circle of the low-permeability ferrite is aligned with the outer circle of the circular body.

5. The RFID antenna with non-uniform field strength according to claim 1, characterized in that: The high magnetic permeability ferrite and the low magnetic permeability ferrite have the same thickness.

6. The RFID antenna with non-uniform field strength according to claim 1, characterized in that: The high magnetic permeability ferrite and the low magnetic permeability ferrite are pasted on the PCB antenna.

7. A ticket card, characterized in that: An RFID antenna with non-uniform field strength as claimed in any one of claims 1 to 6 is provided.

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