Long-distance anti-metal double-shaft 125kHz RFID access control antenna

Abstract

The utility model discloses a long-distance anti-metal biaxial 125kHz RFID access control antenna, including RFID reading coil, flexible soft magnetic film and metal layer, flexible soft magnetic film is provided on one side of RFID reading coil, metal layer is provided on one side of flexible soft magnetic film far away from RFID reading coil, RFID reading coil includes Y-axis coil and X-axis coil, the Y-axis coil and the X-axis coil are connected in parallel, and the X-axis coil and the Y-axis coil are connected in parallel. According to the RFID reading coil, the Y-axis coil and the X-axis coil form two axial magnetic fields in an orthogonal mode, the position adaptability of the RFID reading coil to a tag card is further improved, the coil Q value and self-inductance are optimized by optimizing the number of turns and the wire diameter, the magnetic field receiving and transmitting capacity is improved, long-distance recognition is achieved, and the RFID reading coil has the advantages of being simple in structure and convenient to use. The flexible soft magnetic film and the metal layer are additionally arranged on the back of the RFID reading coil, so that shielding of a backward magnetic field is achieved, and the recognition distance can be further increased.

Description

Technical Field

[0001] The utility model relates to the technical field of RFID access control antennas, in particular to a long-distance anti-metal dual-axis 125kHz RFID access control antenna. Background Art

[0002] For RFID access control systems, three main frequencies are commonly used: low frequency (LF, 125kHz and 134.2kHz), high frequency (HF, 13.56MHz) and ultra-high frequency (UHF, 860MHz to 960MHz). Compared with ultra-high frequency RFID, the 125kHz RFID system can penetrate snow, fog, ice, paint, dirt and other harsh environments for tag reading, has excellent environmental adaptability, and has low hardware cost and compact design. It has strong anti-interference ability and good stability. It is widely used, but there are also the following two problems:

[0003] 1. Limited card reading distance: Compared with high-frequency and ultra-high-frequency RFID systems, the card reading distance of the 125kHz RFID system is relatively short and may not be suitable for all scenarios;

[0004] 2. Affected by metal: Metal objects will have a certain impact on the card reading effect of the 125kHz RFID system, resulting in a shortened card reading distance or card reading failure.

[0005] Therefore, it is particularly important to design a long-distance anti-metal dual-axis 125kHz RFID access control antenna to solve the problems raised by the above background technology. Utility Model Content

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a long-distance anti-metal dual-axis 125kHz RFID access control antenna to solve the deficiencies in the background technology.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A long-distance metal-resistant dual-axis 125kHz RFID access control antenna comprises an RFID reading coil, a flexible soft magnetic film and a metal layer, wherein the flexible soft magnetic film is arranged on one side of the RFID reading coil, and the metal layer is arranged on the side of the flexible soft magnetic film away from the RFID reading coil. The RFID reading coil comprises a Y-axial coil and an X-axial coil, wherein the X-axial coil is located inside the Y-axial coil, and the self-inductance of the Y-axial coil is consistent with that of the X-axial coil.

[0009] As a preferred solution of the utility model, the Y-axis coil is wound by a 0.1*100-strand Litz coil, with a width and height size of 15cm*70cm, a self-inductance of 170μH, and a Q value of 200.

[0010] As a preferred solution of the utility model, the X-axial coil is wound by a 0.1*100-strand Litz coil, with a width and height size of 3cm*66cm and a self-inductance of 170μH.

[0011] As a preferred solution of the present invention, the Y-axial coil and the X-axial coil construct two axial magnetic fields in an orthogonal manner.

[0012] As a preferred solution of the utility model, the flexible soft magnetic film is fixedly connected to the RFID reading coil, the thickness of the flexible soft magnetic film is between 0.5 mm and 2 mm, and the magnetic permeability of the flexible soft magnetic film is 1000.

[0013] As a preferred solution of the utility model, the metal layer is fixedly connected to the flexible soft magnetic film, and the metal layer is made of one of copper foil and aluminum plate.

[0014] As a preferred solution of the present invention, the thickness of the metal layer is 2 mm.

[0015] Compared with the prior art, the beneficial effects of the utility model are:

[0016] The utility model constructs two axial magnetic fields in an orthogonal manner through the Y-axial coil and the X-axial coil of the RFID reading coil, further improving the position adaptability of the RFID reading coil to the tag card, optimizing the coil Q value and self-inductance by optimizing the number of turns and wire diameter, improving the ability to receive and transmit magnetic fields, and thus realizing long-distance identification, and adding a flexible soft magnetic film and a metal layer to the back of the RFID reading coil to shield the backward magnetic field, significantly weaken the backward magnetic field of the RFID reading coil, and enhance the forward magnetic field, thereby reducing the impact of the installation environment on the access control antenna. The proposed scheme can further increase the identification distance for the access control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a long-distance, metal-resistant dual-axis 125kHz RFID access control antenna.

[0018] In the figure: 1. RFID reading coil; 101. Y-axis coil; 102. X-axis coil; 2. Flexible soft magnetic film; 3. Metal layer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0020] Example:

[0021] See also Figure 1 The present embodiment provides a long-distance anti-metal dual-axis 125kHz RFID access control antenna, the frequency of the access control antenna is 125kHz, including an RFID reading coil 1, a flexible soft magnetic film 2 and a metal layer 3, the flexible soft magnetic film 2 is arranged on one side of the RFID reading coil 1, the metal layer 3 is arranged on the side of the flexible soft magnetic film 2 away from the RFID reading coil 1, the RFID reading coil 1 includes a Y-axial coil 101 and an X-axial coil 102, the X-axial coil 102 is located inside the Y-axial coil 101, and the self-inductance of the Y-axial coil 101 is consistent with that of the X-axial coil 102.

[0022] In this embodiment, the Y-axis coil 101 and the X-axis coil 102 construct two axial magnetic fields in an orthogonal manner, further improving the position adaptability of the RFID reading coil 1 to the tag card.

[0023] In this embodiment, the Y-axis coil 101 is wound by a 0.1*100-strand Litz coil, with a width and height of 15cm*70cm, a self-inductance of 170μH, a Q value of 200, and the number of turns of the Y-axis coil 101 is close to 8 to 10 turns. The X-axis coil 102 is wound by a 0.1*100-strand Litz coil, with a width and height of 3cm*66cm, a self-inductance of 170μH, and the number of turns of the X-axis coil 102 is close to 15 turns. The self-inductance of the Y-axis coil 101 and the X-axis coil 102 is consistent, in order to reduce the matching and debugging work of the transmitting circuit. The number of turns and wire diameter of the Y-axis coil 101 and the X-axis coil 102 are optimized to optimize the coil Q value and self-inductance, thereby improving the ability to transmit and receive magnetic fields, thereby achieving long-distance recognition.

[0024] In this embodiment, the flexible soft magnetic film 2 is fixedly connected to the RFID reading coil 1, the thickness of the flexible soft magnetic film 2 is between 0.5 mm and 2 mm, the magnetic permeability of the flexible soft magnetic film 2 is 1000, and a soft magnetic film with higher magnetic permeability can also be selected to further enhance the magnetic field convergence effect. The metal layer 3 is fixedly connected to the flexible soft magnetic film 2, and the metal layer 3 is made of one of copper foil or aluminum plate. The thickness of the metal layer 3 is 2 mm, and the metal layer 3 is close to the flexible soft magnetic film 2. It can be pasted with copper foil or constructed with materials such as aluminum plate. By adding the flexible soft magnetic film 2 and the metal layer 3 to the back of the RFID reading coil 1, the backward magnetic field is shielded, thereby reducing the impact of the installation environment on the access control antenna.

[0025] Through Ansys Maxwell simulation, the parameters of RFID reading coil 1 and magnetic field size under different conditions are compared (under the condition of driving current 2A), as shown in Table 1 below:

[0026] Table 1

[0027]

[0028] To summarize, Table 1 shows the self-inductance of the y-axis coil 101 and the magnitude of the axial forward and reverse magnetic fields under different conditions. It can be seen that after the introduction of the flexible soft magnetic film 2 and the metal layer 3, the backward magnetic field of the coil is significantly weakened, and the forward magnetic field is enhanced. Therefore, the solution proposed in this embodiment can further increase the recognition distance for the access control system. After testing, the RFID access control antenna proposed in this application, in the test combined with the reading circuit, can achieve a maximum forward recognition distance of 1.2 meters, which overcomes the shortcomings of the traditional 125kHz RFID access control system and is very suitable for access control system applications with longer distance recognition.

[0029] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

Claims

1. A long-range anti-metal dual-axis 125kHz RFID access control antenna, characterized by: The invention comprises an RFID reading coil (1), a flexible soft magnetic film (2) and a metal layer (3), wherein the flexible soft magnetic film (2) is arranged on one side of the RFID reading coil (1), and the metal layer (3) is arranged on the side of the flexible soft magnetic film (2) away from the RFID reading coil (1). The RFID reading coil (1) comprises a Y-axial coil (101) and an X-axial coil (102), wherein the X-axial coil (102) is located inside the Y-axial coil (101), and the self-inductance of the Y-axial coil (101) is consistent with that of the X-axial coil (102).

2. The long-distance anti-metal dual-axis 125kHz RFID access control antenna according to claim 1, characterized in that: The Y-axis coil (101) is wound by a 0.1*100-strand Litz coil, has a width and height of 15 cm*70 cm, a self-inductance of 170 μH, and a Q value of 200.

3. The long-distance anti-metal dual-axis 125kHz RFID access control antenna according to claim 1, characterized in that: The X-axis coil (102) is wound by a 0.1*100-strand Litz coil, has a width and height of 3 cm*66 cm, and a self-inductance of 170 μH.

4. The long-distance anti-metal dual-axis 125kHz RFID access control antenna according to claim 1, characterized in that: The Y-axial coil (101) and the X-axial coil (102) construct two axial magnetic fields in an orthogonal manner.

5. The long-distance anti-metal dual-axis 125kHz RFID access control antenna according to claim 1, characterized in that: The flexible soft magnetic film (2) is fixedly connected to the RFID reading coil (1), the thickness of the flexible soft magnetic film (2) is between 0.5 mm and 2 mm, and the magnetic permeability of the flexible soft magnetic film (2) is 1000.

6. The long-distance anti-metal dual-axis 125kHz RFID access control antenna according to claim 1, characterized in that: The metal layer (3) is fixedly connected to the flexible soft magnetic film (2), and the metal layer (3) is made of one of copper foil and aluminum plate.

7. The long-distance anti-metal dual-axis 125kHz RFID access control antenna according to claim 6, characterized in that: The thickness of the metal layer (3) is 2 mm.

Images