Metal patch type radio frequency tag

Abstract

The utility model relates to a metal patch type radio frequency tag, which takes a bearing base material (2) as a carrier, a near-field inductance ring (7) consisting of a radio frequency chip (1) and a main wire (4) and far-field radiation antennas (6) connected with the near-field inductance ring (7) are arranged on the surface of the bearing base material (2), and the far-field radiation antennas (6) are connected with the near-field inductance ring (7) on the basis of a radio frequency port capacitor of the radio frequency chip (1). In cooperation with the metal patch (3) arranged on the other surface opposite to the surface of the near-field inductance ring (7), a plate capacitor structure is additionally arranged, so that the total capacitance of the radio frequency tag structure is increased, the inductance of the radio frequency tag structure under the fixed resonant frequency is reduced, the application size of the near-field inductance ring (7) is reduced, and the cost is reduced. Therefore, a larger laying space is provided for the far-field radiation antenna (6) on the surface of the bearing substrate (2), the laying of the far-field radiation antenna (6) with a larger size is realized, and the working efficiency of the radio frequency tag is improved.

Description

Technical Field

[0001] The utility model relates to a metal patch type radio frequency tag, belonging to the technical field of radio frequency. Background Art

[0002] Ultra-high frequency RFID technology is widely used in clothing, logistics, asset management, and other fields due to its advantages such as passivity, group readability, low cost, and long-range identification. As RFID chip performance continues to improve, the size of the attached object or the area available for attachment are limited in an increasing number of scenarios, resulting in increasing demands for smaller tag antennas. UHF RFID antennas generally consist of a near-field inductor loop and a far-field radiating dipole antenna. The port of a typical chip exhibits capacitive characteristics, which, when combined with the near-field inductor loop, produces an LC resonance effect. When the resonant frequency is fixed, the smaller the chip port capacitance, the greater the required inductor, and the larger the inductor value, the larger the size of the inductor loop. When the inductor loop is large and the overall tag antenna is small, the space left for the far-field radiating dipole antenna becomes smaller, and the performance of the far-field radiating dipole antenna deteriorates, resulting in insufficient performance of the entire UHF RFID tag. Conventional solutions are: (1) using multiple zigzag lines to extend the path to increase the inductance; (2) using thinner line widths to increase the inductance per unit path. However, both of these solutions increase the resistance loss while increasing the inductance, resulting in performance degradation. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a metal patch type radio frequency tag, which uses metal patches combined with wiring to construct a flat capacitor structure, thereby increasing the total capacitance of the radio frequency tag, reducing the inductance at a fixed resonant frequency, and improving the working efficiency of the radio frequency chip.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: the present invention designs a metal patch type radio frequency tag, comprising a radio frequency chip, a carrier substrate, a metal patch, and a main trace, two branch traces, and two far-field radiating antennas arranged on one surface of the carrier substrate, wherein a gap of a preset spacing is maintained between the beginning and end of the main trace, and the radio frequency transmitting port and the radio frequency receiving port on the radio frequency chip are respectively connected to the beginning and end of the main trace on both sides of the gap, and the radio frequency chip and the main trace form a near-field inductance loop; the two far-field radiating antennas are respectively connected to the same position of the near-field inductance loop through a branch trace; the metal patch is attached to the other surface of the carrier substrate, and along the projection direction perpendicular to the surface of the carrier substrate, the projection of the metal patch jumps over the projection of the gap between the beginning and end of the main trace, and overlaps with the projection of the beginning and end of the main trace, and the local area of the main trace where the metal patch and its projection overlap constitutes a flat capacitor structure.

[0005] As a preferred technical solution of the present invention: along the projection direction perpendicular to the surface of the supporting substrate, the projection of the radio frequency chip is located within the projection of the metal patch.

[0006] As a preferred technical solution of the present invention, each branch line is arranged on the surface of the supporting substrate in an S-shaped manner.

[0007] As a preferred technical solution of the present invention: the far-field radiation antenna is arranged in a planar structure on the surface of the supporting substrate.

[0008] As an optimal technical solution of the present invention: the far-field radiating antenna is a far-field radiating dipole antenna.

[0009] As an optimal technical solution of the present invention: based on the connection line between the position of the field inductance ring close to the two branch lines and the position of the RF chip, the overall structure of the two far-field radiating antennas and the branch lines connected thereto are respectively axially symmetrically distributed with the connection line as the symmetry axis.

[0010] The metal patch type radio frequency tag described in the utility model adopts the above technical solution and has the following technical effects compared with the existing technology:

[0011] The utility model designs a metal patch type radio frequency tag, which uses a carrying substrate as a carrier, and has a near-field inductance loop composed of a radio frequency chip and a main trace, as well as various far-field radiation antennas connected to the near-field inductance loop arranged on the surface. On the basis of the radio frequency port capacitance of the radio frequency chip, a metal patch is arranged on the other surface opposite to the surface where the near-field inductance loop is arranged, and a flat capacitor structure is added to increase the total capacitance of the radio frequency tag structure, reduce the inductance of the radio frequency tag structure at a fixed resonant frequency, and reduce the application size of the near-field inductance loop. In addition, a larger layout space is provided on the surface of the carrying substrate for the far-field radiation antenna, thereby realizing the layout of a larger-sized far-field radiation antenna and improving the working efficiency of the radio frequency tag. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a front view of the metal patch type radio frequency tag designed by the present invention;

[0013] Figure 2 This is a schematic diagram of the back of the metal patch type radio frequency tag designed by the present invention;

[0014] Figure 3 This is a schematic diagram of the application and implementation performance of the metal patch type radio frequency tag designed by the utility model.

[0015] Among them, 1. RF chip, 2. Carrying substrate, 3. Metal patch, 4. Main trace, 5. Branch trace, 6. Far-field radiating antenna, 7. Near-field inductor ring. DETAILED DESCRIPTION

[0016] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings.

[0017] The utility model designs a metal patch type radio frequency tag, which is used in actual applications, such as Figure 1 and Figure 2 As shown, the specific design includes an RF chip 1, a carrier substrate 2, a metal patch 3, and a main trace 4, two branch traces 5, and two far-field radiating antennas 6 arranged on one surface of the carrier substrate 2, wherein a gap of a preset spacing is maintained between the head and tail of the main trace 4, and the RF transmitting port and the RF receiving port on the RF chip 1 are respectively connected to the head and tail ends of the main trace 4 on both sides of the gap, and the RF chip 1 and the main trace 4 form a near-field inductor loop 7; the two far-field radiating antennas 6 are respectively connected to the same position of the near-field inductor loop 7 through a branch trace 7; the metal patch 3 is attached to the other surface of the carrier substrate 2, and along the projection direction perpendicular to the surface of the carrier substrate 2, the projection of the metal patch 3 crosses the projection of the gap between the head and tail of the main trace 4, and overlaps with the projection of the head and tail ends of the main trace 4, and the local area of the main trace 4 overlapped by the metal patch 3 and its projection constitutes a flat capacitor structure, that is, the metal patch 3 and the RF chip 1 are arranged on two sides of the carrier substrate 2.

[0018] That is, based on the RF port capacitance of the RF chip 1, the main traces 4 and the metal patch 3 arranged on both sides of the carrier substrate 2 construct a flat capacitor structure, thereby increasing the total capacitance of the RF tag structure.

[0019] Based on the above design, in actual application, further specific design is required, such as Figure 1 As shown, along the projection direction perpendicular to the surface of the carrier substrate 2, the projection of the RF chip 1 is located within the projection of the metal patch 3; and in order to provide a larger layout area for the far-field radiation antenna 6 on the surface of the carrier substrate 2, each branch line 5 can be designed to be laid out in an S-shaped layout on the surface of the carrier substrate 2, thereby realizing the layout application of a larger size far-field radiation antenna 6, and specifically for the far-field radiation antenna 6, a surface structure is adopted to be laid out on the surface of the carrier substrate 2.

[0020] The metal patch RFID tag designed above is applied in practice, such as Figure 1 and Figure 2As shown, the far-field radiating antenna 6 specifically adopts a far-field radiating dipole antenna, and in terms of the overall structural design, based on the connection between the position of the field inductance ring 7 close to the two branch traces 5 and the position of the RF chip 1, the two far-field radiating antennas 6 and the overall structure of the branch traces 5 connected thereto are axially symmetrically distributed with the connection as the symmetry axis. Here, in actual applications, the metal patch 3 can be made of conductors such as gold, silver, and copper, or printed materials such as silver paste, as long as the projected overlapping structure between it and the main trace 4 on the supporting substrate 2 has a flat capacitor effect.

[0021] During actual application, the far-field radiating dipole antenna of the RFID tag will generate an induced current when it receives the electromagnetic field in space. The metal patch 3 located on the surface of the carrier substrate 2 and the main trace 4 project the overlapping area to form a flat capacitor structure. The corresponding induced voltage of the induced current generated by the far-field radiating dipole antenna forms a parallel capacitor at the position of the flat capacitor structure. The parallel capacitor is combined with the RF port capacitance on the RF chip 1, so that the total capacitance value of the RFID tag is increased, and the demand for inductance value at a fixed resonant frequency is reduced, thereby reducing the application size of the near-field inductor ring 7, providing a larger layout space for the far-field radiating antenna 6 on the surface of the carrier substrate 2, and realizing the layout of a larger-sized far-field radiating antenna 6.

[0022] In practical applications of the metal patch type RFID tag designed by the present invention, the projection of the metal patch 3 is designed to partially or completely cover the projection of the gap between the beginning and the end of the main trace 4 along the projection direction perpendicular to the surface of the carrier substrate 2. The larger the area of overlap between the projection of the metal patch 3 and the near-field inductor ring 7, the more obvious the impedance adjustment effect. Figure 3 As shown, as the length S of the metal patch 3 increases from 0 mm to 2 mm, the resonant frequency of the RFID tag antenna decreases continuously. In practical applications, the design of the present invention is not only applicable to the UHF band, but also to the HF band.

[0023] The utility model designs a metal patch type radio frequency tag, which uses a carrying substrate 2 as a carrier, and has a near-field inductance loop 7 composed of a radio frequency chip 1 and a main trace 4, and various far-field radiation antennas 6 connected to the near-field inductance loop 7 arranged on the surface. On the basis of the radio frequency port capacitance of the radio frequency chip 1, a metal patch 3 is arranged on the other surface opposite to the surface where the near-field inductance loop 7 is set, and a flat capacitor structure is added to increase the total capacitance of the radio frequency tag structure, reduce the inductance of the radio frequency tag structure at a fixed resonant frequency, and reduce the application size of the near-field inductance loop 7. Therefore, a larger layout space is provided on the surface of the carrying substrate 2 for the far-field radiation antenna 6, thereby realizing the layout of a larger-sized far-field radiation antenna 6 and improving the working efficiency of the radio frequency tag.

[0024] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A metal patch radio frequency tag, characterized by: The invention comprises a radio frequency chip (1), a carrier substrate (2), a metal patch (3), a main trace (4) arranged on one surface of the carrier substrate (2), two branch traces (5), and two far-field radiation antennas (6), wherein a gap of a preset distance is maintained between the head and tail of the main trace (4), and a radio frequency transmitting port and a radio frequency receiving port on the radio frequency chip (1) are respectively connected to the head and tail ends of the main trace (4) on both sides of the gap, and a near-field inductor loop (7) is formed by the radio frequency chip (1) and the main trace (4). The two far-field radiating antennas (6) are respectively connected to the same position of the near-field inductor ring (7) through a branch line (5); the metal patch (3) is attached to the other surface of the carrier substrate (2), and along the projection direction perpendicular to the surface of the carrier substrate (2), the projection of the metal patch (3) crosses the projection of the gap between the head and tail of the main line (4), and overlaps with the projection of the head and tail of the main line (4), and the local area of the main line (4) where the metal patch (3) and its projection overlap constitutes a flat capacitor structure.

2. The metal patch radio frequency tag according to claim 1, characterized in that: Along a projection direction perpendicular to the surface of the supporting substrate (2), the projection of the radio frequency chip (1) is located within the projection of the metal patch (3).

3. The metal patch type radio frequency tag according to claim 1, characterized in that: Each branch line (5) is arranged on the surface of the supporting substrate (2) in an S-shaped arrangement.

4. The metal patch type radio frequency tag according to claim 1, characterized in that: The far-field radiation antenna (6) is arranged in a planar structure on the surface of the supporting substrate (2).

5. The metal patch type radio frequency tag according to claim 1, characterized in that: The far-field radiating antenna (6) is a far-field radiating dipole antenna.

6. The metal patch type radio frequency tag according to any one of claims 1 to 5, characterized in that: Based on the connection line between the position of the field inductance ring (7) close to the two branch lines (5) and the position of the radio frequency chip (1), the overall structure of the two far-field radiation antennas (6) and the branch lines (5) connected thereto are respectively axially symmetrically distributed with the connection line as the symmetry axis.

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