NFC expander and system

Abstract

The utility model provides an NFC (Near Field Communication) expander and an NFC expansion system. The NFC expander comprises a first antenna structure, a second antenna structure and a transmission line, the first antenna structure comprises a first impedance resonance circuit and a second impedance resonance circuit, the second antenna structure comprises a third impedance resonance circuit and a fourth impedance resonance circuit, and the transmission line comprises a first cable and a second cable. The two ends of the first impedance resonance circuit are correspondingly and electrically connected to the two ends of the third impedance resonance circuit through the first cable and the second cable respectively, and the second cable is electrically connected between the first impedance resonance circuit and the second impedance resonance circuit and between the third impedance resonance circuit and the fourth impedance resonance circuit. Therefore, the NFC expander and the system provided by the utility model can prolong the card reading identification area of the card reading equipment, can break through the limitation that the card reading area is shielded by a thick wood plate, glass and metal at the installation position of the card reading equipment, so that the card cannot be read smoothly, and are practical and convenient.

Description

Technical Field

[0001] This application relates to the technical field of antennas, and in particular, to an NFC extender and a system. Background Art

[0002] With the development of antenna technology, Near Field Communication (NFC) has been more widely used. Among them, the NFC card reader device needs to be relatively close to the non-contact card to complete the reading of card information. Therefore, the card reading area of the card reader device is small and the operation is inconvenient. Utility Model Content

[0003] In view of the above problems, this application provides an NFC extender and a system, which can extend the card reading and identification area of the card reader device, and can break through the limitations such as the card reading area being blocked by thick wooden boards, glass, or metal at the installation position of the card reader device, resulting in the inability to smoothly read the card, which is practical and convenient.

[0004] In a first aspect, this application provides an NFC extender. The NFC extender includes a first antenna structure, a second antenna structure, and a transmission line. The transmission line is electrically connected between the first antenna structure and the second antenna structure. The first antenna structure is used to couple with the card reader device to receive a card reading instruction signal, and transmit the card reading instruction signal to the second antenna structure through the transmission line. The second antenna structure is used to couple with the non-contact card to transmit the card reading instruction signal into the non-contact card. The first antenna structure includes a first impedance resonance circuit and a second impedance resonance circuit. The second antenna structure includes a third impedance resonance circuit and a fourth impedance resonance circuit. The transmission line includes a first cable and a second cable. Two ends of the first impedance resonance circuit are respectively electrically connected to two ends of the third impedance resonance circuit through the first cable and the second cable. The second cable is electrically connected between the first impedance resonance circuit and the second impedance resonance circuit, and between the third impedance resonance circuit and the fourth impedance resonance circuit.

[0005] In combination with the first aspect, in a possible implementation manner, the first antenna structure further includes a first coil. One end of the first coil is electrically connected to one end of the first cable and the first impedance resonance circuit, and the other end of the first coil is electrically connected to one end of the second impedance resonance circuit.

[0006] In combination with the first aspect, in a possible implementation manner, the first antenna structure further includes a first matching resistor. The first matching resistor is electrically connected between the other end of the first coil and one end of the second impedance resonance circuit.

[0007] In combination with the first aspect, in a possible implementation manner, the second antenna structure further includes a second coil. One end of the second coil is electrically connected to one end of the first cable and the third impedance resonance circuit, and the other end of the second coil is electrically connected to one end of the fourth impedance resonance circuit.

[0008] In combination with the first aspect, in a possible implementation manner, the second antenna structure further includes a second matching resistor, and the second matching resistor is electrically connected between the other end of the second coil and one end of the fourth impedance resonance circuit.

[0009] In combination with the first aspect, in a possible implementation manner, the output impedance of the first antenna structure is equal to the characteristic impedance of the transmission line.

[0010] In combination with the first aspect, in a possible implementation manner, the second antenna structure is further configured to receive the card information signal output by the non-contact card, and transmit the card information signal to the first antenna structure through the transmission line; the first antenna structure is further configured to transmit the card information signal to the card reading device.

[0011] In combination with the first aspect, in a possible implementation manner, both the first cable and the second cable are coaxial cables.

[0012] In combination with the first aspect, in a possible implementation manner, the first impedance resonance circuit includes a first capacitor, the second impedance resonance circuit includes a second capacitor, the third impedance resonance circuit includes a third capacitor, and the fourth impedance resonance circuit includes a fourth capacitor.

[0013] In a second aspect, the present application provides an NFC extension system, including a card reading device and an NFC expander provided in any possible implementation manner of the first aspect. The NFC expander is coupled to the card reading device. The card reading device is configured to transmit a card reading instruction signal to the non-contact card through the NFC expander, and receive a card information signal from the non-contact card through the NFC expander. Description of the Drawings

[0014] Figure 1 It is a schematic diagram of the NFC extension system provided by the present application.

[0015] Figure 2 It is a schematic diagram of the NFC expander provided by the present application.

[0016] Figure 3 It is another schematic diagram of the NFC expander provided by the present application.

[0017] Figure 4 It is a circuit diagram of the NFC expander provided by the present application.

[0018] Figure 5 It is an application scenario diagram of the NFC expander provided by the present application. Detailed Embodiments

[0019] Next, the technical solutions in the embodiments of the present application will be clearly described in conjunction with the accompanying drawings in the embodiments of the present application.

[0020] It is understandable that the connection relationships described in this application refer to direct or indirect connections. For example, when A is connected to B, it can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components. For example, it can be a direct connection between A and C, and a direct connection between C and B, so that A and B are connected through C. It is also understandable that "A is connected to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0021] In the description of this application, unless otherwise specified, " / " means "or". For example, A / B can mean A or B. "And / or" herein is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0022] In the description of this application, words such as "first" and "second" are only used to distinguish different objects, and do not limit the quantity and execution order, and the words "first" and "second" do not necessarily mean different. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0023] With the development of antenna technology, Near Field Communication (NFC) has been more widely used. Among them, the NFC card reading device needs to be relatively close to the non-contact card to complete the reading of card information. Therefore, the card reading area of the card reading device is small and the operation is inconvenient.

[0024] For example, in a scenario where the card reading device must be installed behind obstacles such as a thick wooden countertop, double-layer glass, and metal magnetic separation materials, due to the isolation of the obstacles, the distance between the card reading area of the card reading device and the non-contact card is relatively far, or the obstacles may reduce the intensity of the electromagnetic signal between the card reading device and the non-contact card, resulting in the card reading device may fail to read the card, making the user experience poor.

[0025] Another example is that in a scenario where the card reading device is a merchant POS machine and the non-contact card is a bank card, to meet the security requirements, there must be a certain distance between the merchant cashier staff and the paying customer. In this way, the merchant cashier staff needs to hold the POS machine far away and close to the customer to read the information of the bank card and complete the payment. Such frequent and tiring actions also make the merchant staff less flexible and have a poor experience.

[0026] Accordingly, the present application provides an NFC extender and a system, which can extend the card reading and recognition area of a card reading device, and can break through the limitations such as the card reading area being blocked by thick wooden boards, glass, or metal at the installation position of the card reading device, resulting in the inability to smoothly read the card, which is practical and convenient.

[0027] Specifically, please refer to Figure 1 , Figure 1 which is a schematic diagram of the NFC extension system 10 provided by the present application. The NFC extension system 10 includes a card reading device 11, an NFC extender 12, and a contactless card 13.

[0028] The card reading device 11 is configured to transmit a card reading instruction signal to the contactless card 13 through the NFC extender 12, and receive a card information signal of the contactless card 13 through the NFC extender 12. Among them, after the card reading device 11 transmits a card reading instruction signal to the contactless card 13 through the NFC extender 12, the contactless card 13 can feedback a card information signal including card number and other card information based on the card reading instruction signal, and transmit it to the card reading device 11 through the NFC extender 12.

[0029] In some embodiments, the card reading device 11 can be a POS machine, an NFC card reader, an access control card reader, a terminal device with NFC card reading function, etc. The contactless card 13 can be a physical card such as a bank card, an NFC electronic tag, an access control card, a contactless integrated circuit card, a bus card, etc., or a terminal device with NFC simulation function, etc.

[0030] Thus, the NFC extender 12 is disposed between the card reading device 11 and the contactless card 13, which can effectively extend the card reading range of the card reading device 11 and improve the user's card reading or card tapping experience.

[0031] Next, the composition and working principle of the NFC extender 12 will be specifically described.

[0032] Please refer to Figure 2 , Figure 2 which is a schematic diagram of the NFC extender 12 provided by the present application. The NFC extender 12 includes a first antenna structure 121, a transmission line 122, and a second antenna structure 123. The first antenna structure 121 is electrically connected to the second antenna structure 123 through the transmission line 122.

[0033] The first antenna structure 121 is configured to be coupled with the card reading device 11 to receive a card reading instruction signal, and transmit the card reading instruction signal to the second antenna structure 123 through the transmission line. Specifically, the first antenna structure 121 includes a coil, and the coil of the first antenna structure 121 is coupled with the built-in coil of the card reading device 11, so that based on the electromagnetic induction principle, the card reading instruction signal output from the output coil of the card reading device 11 can be received. The card reading instruction signal can be transmitted to the second antenna structure 123 through the transmission line 122.

[0034] The second antenna structure 123 is used to couple with the non-contact card 13 to transmit the card reading instruction signal into the non-contact card 13. Specifically, the second antenna structure 123 includes a coil, and the coil of the second antenna structure 123 is coupled with the built-in coil of the non-contact card 13, so that based on the principle of electromagnetic induction, the card reading instruction signal can be coupled into the built-in coil of the non-contact card 13.

[0035] The second antenna structure 123 is also used to receive the card information signal output by the non-contact card 13 and transmit the card information signal to the first antenna structure 121 through the transmission line 122. Specifically, when the non-contact card 13 receives the card reading instruction signal, it will output the corresponding card information signal based on the card reading instruction signal and couple it to the coil of the second antenna structure 123. Thus, the second antenna structure 123 can receive the card information signal and transmit it to the first antenna structure 121 through the transmission line 122.

[0036] The first antenna structure 121 is also used to transmit the card information signal to the card reading device 11. Specifically, after receiving the card information signal, the first antenna structure 121 couples and transmits the card information signal to the built-in coil of the card reading device 11 through the coil, so that the card reading device 11 receives the card information signal and completes the card reading process.

[0037] In some embodiments, the components and their connection manners of the first antenna structure 121 and the second antenna structure 123 can be the same, so as to reduce the configuration cost of the NFC extender 12. In other embodiments, the components and their connection manners of the first antenna structure 121 and the second antenna structure 122 can also be configured to be different according to actual requirements, so as to improve the compatibility and adaptability of the NFC extender 12.

[0038] In some embodiments, the transmission line 122 can be a coaxial cable. In this way, the loss of signal transmission can be reduced and the confidentiality of signal transmission can be improved.

[0039] In this way, by setting the first antenna structure 121, the transmission line 122 and the second antenna structure 123, the card reading instruction signal output by the card reading device 11 can be coupled into the built-in coil of the non-contact card 13 through the first antenna structure 121, the transmission line 122 and the second antenna structure 123, and the card information signal of the non-contact card 13 can be transmitted back to the card reading device 11 through the second antenna structure 123, the transmission line 122 and the first antenna structure 121. Thus, the NFC extender 12 can effectively expand the communication distance between the card reading device 11 and the non-contact card 13.

[0040] Please refer to Figure 3 , Figure 3Another schematic diagram of the NFC expander 12 provided by this application. Among them, the first antenna structure 121 includes a first coil 1211, a first impedance resonant circuit 1212, and a second resonant impedance circuit 1213. The transmission line 122 includes a first cable 1221 and a second cable 1222. The second antenna structure 123 includes a second coil 1231, a third impedance resonant circuit 1232, and a fourth impedance resonant circuit 1233.

[0041] The first coil 1211, the first impedance resonant circuit 1212, and the second resonant impedance circuit 1213 enclose to form the first antenna structure 121, and the second coil 1231, the third impedance resonant circuit 1232, and the fourth impedance resonant circuit 1233 enclose to form the second antenna structure 123.

[0042] Both ends of the first impedance resonant circuit 1212 are respectively electrically connected to both ends of the third impedance resonant circuit 1232 through the first cable 1221 and the second cable 1222, and the second cable 1222 is electrically connected between the first impedance resonant circuit 1212 and the second impedance resonant circuit 1213, and between the third impedance resonant circuit 1232 and the fourth impedance resonant circuit 1233.

[0043] The first impedance resonant circuit 1212 and the second resonant impedance circuit 1213 may include one or more capacitors, and the multiple capacitors may be connected in series, parallel, or in a combination of series and parallel with each other. Similarly, the third impedance resonant circuit 1232 and the fourth impedance resonant circuit 1233 may also include one or more capacitors, and the multiple capacitors may be connected in series, parallel, or in a combination of series and parallel with each other.

[0044] In this way, the first coil 1211, the first impedance resonant circuit 1212, and the second resonant impedance circuit 1213 form an RC resonant circuit, and the resonant frequency is determined by the equivalent inductance of the first coil 1211, the equivalent capacitance of the first impedance resonant circuit 1212, and the second resonant impedance circuit 1213. In addition, the output impedance of the first antenna structure 121 is also determined by the equivalent inductance of the first coil 1211, the equivalent capacitance of the first impedance resonant circuit 1212, and the second resonant impedance circuit 1213.

[0045] Please refer to Figure 4 , Figure 4 , the circuit diagram of the NFC expander 12 provided by this application. Among them, the first impedance resonant circuit 1212 includes a capacitor C11, the second resonant impedance circuit 1213 includes a capacitor C12, the third impedance resonant circuit 1232 includes a capacitor C21, and the fourth impedance resonant circuit 1233 includes a capacitor C22. The first coil 1211 can be equivalently connected in series with the first coil inductance and the equivalent resistance RS, and the second coil 1231 can be equivalently connected in series with the second coil inductance and the equivalent resistance Rs.

[0046] In addition, the first antenna structure 121 further includes a resistor R1, and the second antenna structure 123 further includes a resistor R2. Two ends of the resistor R1 are electrically connected to one end of the capacitor C12 and one end of the first coil 1211 respectively. Two ends of the resistor R2 are electrically connected to one end of the capacitor C22 and one end of the second coil 1231 respectively.

[0047] The resistor R1 and the resistor R2 are used to adjust the Q value of the first antenna structure 121 and the Q value of the second antenna structure 123 respectively. In some embodiments, the resistor R1 and the resistor R2 may be omitted.

[0048] Specifically, the output impedance of the first antenna structure 121 can be obtained by the following formula (1):

[0049]

[0050] where f0 is the resonant frequency, L is the equivalent inductance of the first coil 1211, C 11 is the capacitance value of the capacitor C11, C 12 is the capacitance value of the capacitor C12, R s is the loss resistance of the first antenna structure 121, R t is the radiation resistance of the first antenna structure 121, and R1 is the sum of the resistance value of the resistor R1 and the equivalent resistance value of the series capacitance of the capacitor C11 and the capacitor C12.

[0051] Therefore, it can be seen from the above formula (1) that the output impedance of the first antenna structure 121 is correlated with the resonant frequency of the first antenna structure 121. Since the resonant frequencies of the NFC antenna structures are mostly preset fixed values, for example, 13.56 MHz, it is necessary to adjust the output impedance of the first antenna structure 121 according to the fixed resonant frequency so that the output impedance of the first antenna structure 121 matches the characteristic impedance of the transmission line 122 to reduce the transmission loss of the signal on the transmission line.

[0052] In this application, compared with the difficulty of setting a single impedance resonance circuit to simultaneously meet a specific resonance frequency and a specific output impedance, by setting two impedance resonance circuits, and the two impedance resonance circuits are respectively arranged between two transmission cables and beside one of them, a capacitive voltage division structure can be formed by the two impedance resonance circuits. Furthermore, by flexibly adjusting the number of capacitors, capacitance values, connection relationships, etc. in the first impedance resonance circuit 1212 and the second resonance impedance circuit 1213, or the ratio of the equivalent capacitances of the first impedance resonance circuit 1212 and the second resonance impedance circuit 1213, the resonance frequency and output impedance of the first antenna structure 121 can be adaptively adjusted, so as to be adapted to the first coils 1211 of various structures, facilitating the diversified design of the first coils 1211 and making it easier to simultaneously meet the specific resonance frequency and the specific output impedance. At the same time, the first impedance resonance circuit 1212 and the second resonance impedance circuit 1213 can be used not only to form a resonance frequency but also to achieve impedance matching between the first antenna structure 121 and the transmission line 122, thus enabling the matching circuit to be streamlined and reducing the overall insertion loss of the NFC expander 12.

[0053] Please refer to Figure 5 , when the NFC expander 12 is operating normally, the card reading device 11 outputs a card reading instruction signal, and the card reading instruction signal appears as an alternating electromagnetic wave signal. The first coil 1211 in the first antenna structure 121 is coupled to the card reading device 11. Therefore, based on the principle of electromagnetic induction, the card reading instruction signal can be received, and an induced voltage is generated between the first cable 1221 and the second cable 1222, thereby forming a current loop among the first antenna structure 121, the transmission line 122, and the second antenna structure 123. Since the current flowing through the first antenna structure 121 is equal to the current flowing through the second antenna structure 123, the alternating electromagnetic wave signal radiated by the second coil 1231 of the second antenna structure 123 is the same as the card reading instruction signal. Thus, the NFC expander 12 can extend the card reading area of the card reading device 11.

[0054] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate this application, rather than to limit this application. As long as within the scope of the essential spirit of this application, appropriate changes and variations made to the above embodiments fall within the scope of protection required by this application.

Claims

1. An NFC extender, characterized in that: The NFC extender includes a first antenna structure, a second antenna structure and a transmission line, wherein the transmission line is electrically connected between the first antenna structure and the second antenna structure; The first antenna structure is used to couple with a card reading device to receive a card reading instruction signal, and transmit the card reading instruction signal to the second antenna structure through the transmission line; The second antenna structure is used to couple with a contactless card to transmit the card reading instruction signal to the contactless card; The first antenna structure includes a first impedance resonant circuit and a second impedance resonant circuit, the second antenna structure includes a third impedance resonant circuit and a fourth impedance resonant circuit, the transmission line includes a first cable and a second cable, the two ends of the first impedance resonant circuit are electrically connected to the two ends of the third impedance resonant circuit through the first cable and the second cable respectively, and the second cable is electrically connected between the first impedance resonant circuit and the second impedance resonant circuit, and between the third impedance resonant circuit and the fourth impedance resonant circuit.

2. The NFC extender according to claim 1, characterized in that: The first antenna structure further includes a first coil, one end of which is electrically connected to the first cable and one end of the first impedance resonant circuit, and the other end of the first coil is electrically connected to one end of the second impedance resonant circuit.

3. The NFC extender according to claim 2, characterized in that: The first antenna structure further includes a first matching resistor, which is electrically connected between the other end of the first coil and one end of the second impedance resonant circuit.

4. The NFC extender according to claim 1, wherein: The second antenna structure further includes a second coil, one end of the second coil is electrically connected to the first cable and one end of the third impedance resonant circuit, and the other end of the second coil is electrically connected to one end of the fourth impedance resonant circuit.

5. The NFC extender according to claim 4, characterized in that: The second antenna structure further includes a second matching resistor electrically connected between the other end of the second coil and one end of the fourth impedance resonant circuit.

6. The NFC extender according to claim 1, wherein: The output impedance of the first antenna structure is equal to the characteristic impedance of the transmission line.

7. The NFC extender according to claim 1, wherein: The second antenna structure is also used to receive a card information signal output by a contactless card, and transmit the card information signal to the first antenna structure through the transmission line; The first antenna structure is also used to transmit the card information signal to the card reading device.

8. The NFC extender according to claim 1, wherein: The first cable and the second cable are both coaxial cables.

9. The NFC extender according to claim 1, wherein: The first impedance resonant circuit includes a first capacitor, the second impedance resonant circuit includes a second capacitor, the third impedance resonant circuit includes a third capacitor, and the fourth impedance resonant circuit includes a fourth capacitor.

10. An NFC expansion system, characterized in that: The invention comprises a card reader device and an NFC extender as claimed in any one of claims 1 to 9, wherein the NFC extender is coupled to the card reader device, and the card reader device is used to transmit a card reading instruction signal to a contactless card through the NFC extender, and receive a card information signal from the contactless card through the NFC extender.

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