Circuit unit and NFC device for realizing near field communication

Abstract

To provide a circuit unit and a near field communication (NFC) device for achieving near field communication.SOLUTION: The circuit unit 300 includes an NFC antenna 301, an NFC chip 302, and an exciting circuit 303, where the NFC antenna 301 is connected to the NFC chip 302, and the NFC302 chip is connected to the exciting circuit 303. The NFC chip 302 is configured to obtain first energy when the NFC antenna 301 senses a radio frequency field of a user terminal device, and provide a part of the first energy to the excitation circuit 303, the excitation circuit 303 is configured to generate and emit an excitation signal by using the energy obtained from the NFC chip 302, and the excitation signal is configured to excite the user terminal device to communicate with a device including the circuit unit 300.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present application relates to the field of near field wireless communication technology, and more particularly to a circuit unit and an NFC device for realizing near field wireless communication. [Background technology]

[0002] Near Field Communication (NFC) technology is a short-range wireless communication protocol that has been widely applied in multiple fields, such as mobile payment, information interaction, smart home control, access control, identity authentication and identification, electronic tickets, and anti-counterfeiting. Devices involved in NFC may include an NFC initiator device and an NFC target device. The NFC initiator device (also called a master device) requires a power source device. The master device uses the energy of the power source device to provide a radio frequency field and transmit data to the NFC target device (also called a slave device). The transmission rate must be selected from 106 kbps, 212 kbps, or 424 kbps. The slave device does not generate a radio frequency field or require a power source device. Instead, the master device converts the generated radio frequency field into electrical energy to power the slave device's circuitry, receives data transmitted by the master device, and transmits data from the slave device to the master device at the same transmission rate using load modulation technology.

[0003] In actual applications, when a mobile terminal such as a smartphone is used as an NFC master device, the NFC master device has many low-power designs for the emission power of its own card reader, etc., in order to control power consumption. As a result, the target device can only achieve a good communication success rate by using an active power supply solution to interact with the mobile terminal device, but using a low-cost passive solution with high power consumption and high cost often results in a low communication success rate. This has hindered the large-scale widespread application of near-field wireless communication methods using mobile terminal devices such as smartphones as NFC master devices.

[0004] In view of this, it is necessary to provide a short-range wireless communication scheme with low power consumption and high success rate. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of this, embodiments of the present application provide a circuit unit and an NFC device for realizing short-distance wireless communication in order to improve the success rate of short-distance wireless communication under conditions of low power consumption. [Means for solving the problem]

[0006] According to a first aspect of an embodiment of the present application, there is provided a circuit unit for realizing near field wireless communication, comprising: an NFC antenna, an NFC chip, and an excitation circuit, wherein the NFC antenna is connected to the NFC chip, and the NFC chip is connected to the excitation circuit, wherein the NFC chip is used to obtain first energy when the NFC antenna senses a radio frequency field of a user terminal device, and to provide a portion of the first energy to the excitation circuit, and the excitation circuit is used to generate and emit an excitation signal using the energy obtained from the NFC chip, and the excitation signal is used to excite the user terminal device to communicate with a device including the circuit unit.

[0007] According to a second aspect of an embodiment of the present application, there is provided an NFC device, the device including: a circuit unit for realizing near field wireless communication; the circuit unit including an NFC antenna, an NFC chip, and an excitation circuit; the NFC antenna is connected to the NFC chip; and the NFC chip is connected to the excitation circuit; wherein the NFC chip is used to obtain first energy when the NFC antenna senses a radio frequency field of a user terminal device, and to provide a portion of the first energy to the excitation circuit; the excitation circuit is used to generate and emit an excitation signal using the energy obtained from the NFC chip, and the excitation signal is used to excite the user terminal device to communicate with a device including the circuit unit. [Effects of the Invention]

[0008] One embodiment of this specification can achieve at least the following beneficial effect: by providing an excitation circuit, and using an NFC chip to obtain energy when the NFC antenna senses the radio frequency field of the user terminal device, the excitation circuit emits an excitation signal to excite the user terminal device to switch to the standard card detection mode and further perform near field wireless communication, thereby improving the success rate of near field wireless communication in a low-power manner. [Brief explanation of the drawings]

[0009] In order to more clearly explain the technical solutions in the embodiments or prior art of this specification, the following briefly introduces drawings that need to be used in the description of the embodiments or prior art. It is obvious that the drawings in the following description are only some embodiments described in this application, and those skilled in the art can also obtain other drawings based on these drawings without exerting any creative efforts.

[0010] [Figure 1] 1 is a schematic diagram of an application scenario of a circuit unit for realizing short-range wireless communication according to an embodiment of the present specification; [Figure 2] FIG. 1 is a schematic diagram of a circuit unit for realizing short-range wireless communication according to an embodiment of the present specification. [Figure 3] FIG. 2 is a detailed schematic diagram of a circuit unit for realizing short-range wireless communication according to an embodiment of the present specification. [Figure 4] FIG. 10 is a schematic diagram of a circuit unit for realizing another short-range wireless communication according to an embodiment of the present specification. [Figure 5] FIG. 10 is a schematic diagram of a circuit unit for realizing yet another short-range wireless communication according to an embodiment of the present specification. [Figure 6] FIG. 10 is a schematic diagram of a circuit unit for realizing further near field wireless communication according to an embodiment of the present specification. [Figure 7] 1 is a schematic diagram illustrating a situation in which a circuit unit for realizing short-range wireless communication in a practical application scenario according to an embodiment of the present specification and a user terminal device operating in an active mode perform short-range wireless communication; [Figure 8] 1 is a structural schematic diagram of a metal piece used in an NFC antenna according to an embodiment of the present specification. [Figure 9] 10 is a structural schematic diagram of another metal piece used in an NFC antenna according to an embodiment of the present disclosure. [Figure 10] 1 is a schematic diagram of an NFC antenna including a metal piece and a metal coil, according to an embodiment of the present disclosure. [Figure 11] 1 is a schematic diagram of another NFC antenna including a metal piece and a metal coil according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the following description, many specific details are described to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar applications without departing from the scope of the present application, so the present application is not limited to the specific implementation limitations disclosed below.

[0012] The terminology used in one or more embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to limit one or more embodiments of the present application. As used in one or more embodiments of the present application and in the appended claims, the singular forms "a," "the," "said," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should be further understood that the term "and / or" as used in one or more embodiments of the present application refers to and includes any and all possible combinations of one or more of the associated listed items.

[0013] It should be understood that, although one or more embodiments of the present application may employ terms such as first, second, etc. to describe various pieces of information, such information is not limited to these terms. These terms are used only to distinguish between pieces of information of the same type. For example, a first may be referred to as a second, and similarly, a second may be referred to as a first, without departing from the scope of one or more embodiments of the present application. Depending on the context, for example, the word "if" used herein can be interpreted as "when," "in the case of," or "in response to a determination."

[0014] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data used for storage, data used for presentation, etc.) related to this application are all information and data that have been authorized by the user or have been fully authorized by each party, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant regions, and relevant operation portals are provided for users to select permission or denial.

[0015] First, we will interpret the noun terms associated with one or more embodiments of this application.

[0016] NFC (Near Field Communication) is a short-range, high-frequency radio communication technology.

[0017] NFC active mode: also called card reader mode. In active mode, the NFC device acts as a card reader and emits a radio frequency field to identify and read / write information from passive NFC devices. An NFC device in active mode may be called an active NFC device or an NFC master device.

[0018] NFC passive mode: Also called card simulation mode. In passive mode, an NFC device simulates itself as a card and passively responds to radio frequency fields emitted by other devices, allowing information to be read from or written to it. An NFC device in passive mode may also be called a passive NFC device or an NFC slave device.

[0019] LPCD mode: Low-power card detection mode or low-power card search mode, where LPCD stands for Low Power Card Detection. LPCD is a technology in NFC technology for efficiently detecting nearby contactless smart cards or tags. It is primarily used to reduce power consumption while an NFC card reader waits for a smart card or tag to approach. In LPCD mode, an NFC card reader can periodically transmit low-power pulses. The NFC card reader detects changes in signal amplitude on the antenna. If the changes exceed a preset threshold, it determines that an NFC device is in proximity and can initiate further interaction processes. Specifically, when a card enters a radio frequency field, its presence causes changes in the signal amplitude and phase. LPCD mode uses a software-based card detection mechanism and an LPCD algorithm to detect these changes and analyze the in-phase (I) and quadrature (Q) components of the received signal to determine whether a card is in proximity and trigger further NFC communication. LPCD mode is particularly important for portable devices such as mobile phones, where its main advantage is its low power consumption. Mobile phones typically require long standby times, but frequent activation of NFC functionality can significantly drain battery power. LPCD mode allows the mobile phone to continuously detect NFC signals in the background while maintaining a relatively low energy consumption level. Once a card is detected, the mobile phone can quickly switch from a low-power state to a fully functional state to perform an NFC transaction or data exchange.

[0020] Standard card detection mode: Also known as normal card detection mode or normal card search mode. To increase the rate and success rate of NFC communication, NFC card readers are generally in full-function mode, i.e., standard card detection mode, when conducting NFC communication. In actual application, in both LPCD mode and standard card detection mode, NFC card readers (e.g., mobile terminal devices such as mobile phones) emit a 13.56MHz sine wave. The difference is that the transmission time and amplitude of the sine wave are different in LPCD mode and standard card detection mode. For example, in LPCD mode, the pulse width is generally in the us-level, while in standard card detection mode, the pulse width is generally in the tens of ms level.

[0021] NFC tag: Fully known as a Near Field Communication tag, it is a small device based on near-field wireless communication technology that enables data exchange between devices within a short distance. NFC tags generally contain a microchip and an antenna. The chip stores information (e.g., ID, URL, etc.), while the antenna is responsible for sending and receiving data. NFC tags are passive devices that can operate without an external power source. In practice, when an NFC card reader (e.g., a smart mobile device that supports NFC functionality) is brought close to an NFC tag, the magnetic field generated by the NFC card reader is sensed by the tag's antenna, generating enough power to activate the chip in the tag and allow the tag to transmit the information stored on it.

[0022] NFC technology has been widely applied in multiple fields, such as mobile payment, information interaction, smart home control, access control, identity authentication and identification, electronic tickets, and anti-counterfeiting. For example, in the mobile payment field, payment methods based on NFC technology are currently being actively developed both at home and abroad.

[0023] In the mobile payment scene, the current mainstream NFC-based payment method uses the cash register (receiving device) as a card reader operating in active mode to read passively simulated information on the mobile device (paying device). However, electronic wallets used by consumers are all provided by mobile device manufacturers, and users must enable various wallets as required by the mobile device manufacturer to use the NFC payment function on their mobile devices. This makes management difficult and poses information security risks. Furthermore, not all mobile device models currently support passive card simulation functions such as financial payments, limiting the widespread adoption and application of NFC payment methods that operate in passive mode on mobile devices. In light of this, it is necessary to operate mobile devices in active mode.

[0024] However, NFC payment methods in which mobile devices operate in active mode currently present several practical challenges. Specifically, mobile devices are typically battery-powered and very sensitive to power consumption. To control power consumption, they typically implement various low-power designs, such as LPCD mode, for the emission power of their card readers. For example, when a mobile phone's screen is turned off, the card reader function is typically turned off, and many mobile phones automatically enter LPCD mode shortly after the screen is turned on. When a mobile device in LPCD mode approaches a counterpart NFC target device, it can switch to standard card detection mode. In actual application, the mobile device wakes up from LPCD mode and enters standard card detection mode only when the mobile device detects that the intensity change caused by its emitted radio frequency signal, detected by the counterpart NFC target device in proximity, exceeds a preset threshold. However, in LPCD mode, the signal strength emitted by the mobile device is weaker and the amplitude of the emitted radio frequency signal is lower than in standard card detection mode. As a result, the influence of the other NFC target device on this signal is also reduced accordingly. As a result, the mobile device cannot determine whether there is an NFC target device nearby based on the change in the amplitude of this signal. Furthermore, the mobile device cannot make an accurate judgment and cannot switch to standard card detection mode. This significantly reduces the success rate of the mobile device's detection of an NFC target device, further affecting the success rate of near field wireless communication and affecting the user experience.

[0025] For example, when a smartphone acts as an NFC master device and communicates with a cash register via near-field communication, a good communication success rate can only be achieved when the other party interacts with the mobile phone as an active device. However, active cash registers not only consume high power, but also have complex designs, high costs, and high offline installation costs, making them unsuitable for widespread adoption. On the other hand, low-cost passive payment methods often have low communication success rates (for example, currently, the communication success rate of passive payment methods is less than 70%, and for some mobile device models, it is even less than 50%), and this relatively low success rate also hinders the widespread adoption of this payment mode.

[0026] In view of this, an embodiment of this specification provides a passive low-power short-range wireless communication solution for an NFC slave device. An excitation circuit is provided, and when the NFC antenna senses the radio frequency field of a user terminal device, part of the energy obtained by the NFC chip is provided to the excitation circuit, which then emits an excitation signal to excite the user terminal device and communicate with the NFC slave device. This improves the success rate of short-range wireless communication with low power consumption and low cost, and further promotes the production and popularization of convenient NFC payment products as NFC slave devices.

[0027] FIG. 1 is a schematic diagram of an application scenario of a circuit unit for realizing short-range wireless communication according to an embodiment of the present specification.

[0028] 1, when a mobile terminal 100 having an NFC function is brought into proximity with an NFC tag 201 or a deposit terminal 202 having an NFC function, short-range wireless communication can occur with the NFC tag 201 or the deposit terminal 202, thereby allowing the mobile terminal 100 to obtain information provided by the NFC tag 201 or the deposit terminal 202. In this process, the mobile terminal 100 operates in an active mode, and the NFC tag 201 or the deposit terminal 202 operates in a passive mode.

[0029] 1 shows a mobile terminal 100 in which the NFC master device that initiates NFC communication is a smartphone, but in actual application of the solution of this specification, the NFC master device may further include, but is not limited to, a smart wearable device such as a smart watch or smart glasses. In FIG. 1, the NFC slave device is shown to be an NFC tag 201 or a deposit terminal 202, but in actual application of the solution of this specification, the NFC slave device may further include, but is not limited to, an electronic door lock, a payment code card, an entrance / exit gate, etc.

[0030] In actual application, an NFC master device such as the mobile terminal 100 can emit a radio frequency field, and an NFC slave device such as the NFC tag 201 or the deposit terminal 202 can respond by detecting the near field communication signal emitted from the NFC master device and transmit service information to the mobile terminal 100. Here, the service information may vary depending on the application scenario. For example, in a payment scenario, the service information may include payment order information, or in a meal ordering scenario, the service information may include a unified resource locator for opening a meal ordering page, or in product traceability, the service information may include product description information.

[0031] A circuit unit for realizing near field communication provided by the solutions of the embodiments of the present specification may be attached to an NFC slave device such as the NFC tag 201 or the deposit terminal 202 shown in Fig. 1. The NFC device provided by the solutions of the embodiments of the present specification may be used as, for example, the NFC tag 201 or the deposit terminal 202 shown in Fig. 1.

[0032] In the solution according to the embodiment of the specification, in a circuit unit for realizing short-range wireless communication, the NFC chip's own ability to recover energy from the radio frequency field of a nearby user terminal device is utilized, and the recovered energy is provided to an excitation module, which then excites the user terminal device, so that the user terminal device can sense the presence of an NFC slave device (which includes a circuit unit according to the embodiment of the specification) and further perform normal short-range wireless communication with the NFC slave device.

[0033] One or more embodiments of the present disclosure provide a circuit unit for implementing short-range wireless communication.

[0034] FIG. 2 shows a schematic diagram of a circuit unit 300 for realizing short-range wireless communication according to an embodiment of the present specification.

[0035] As shown in FIG. 2, specifically, a circuit unit 300 for realizing short-range wireless communication may include an NFC antenna 301, an NFC chip 302, and an excitation circuit 303, and the NFC chip 302 may be connected to the NFC antenna 301, and the NFC chip 302 may be connected to the excitation circuit 303.

[0036] Here, the NFC chip 302 and the NFC antenna 301 connected thereto may have the capability of transmitting and receiving signals and modulating and demodulating signals. Specifically, the NFC chip 302 and the NFC antenna 301 connected thereto may operate in a passive mode and directly communicate with a counterpart user terminal device (e.g., a smartphone) operating in an active mode.

[0037] The communication carrier frequency of NFC (Near Field Communication) technology is 13.56 MHz. This frequency is standardized globally, allowing NFC devices from different manufacturers to be compatible with each other. The 13.56 MHz frequency is selected to ensure efficient and secure data exchange within a short distance (typically a few centimeters to approximately 20 centimeters). The radio frequency field with a communication carrier frequency of 13.56 MHz has the ability to provide an energy field. The radio frequency field emitted from an NFC master device operating in active mode can generally provide energy to an NFC slave device. An NFC slave device operating in passive mode can be directly powered by energy provided by an NFC master device lock to complete communication with the NFC master device. In the embodiments of the present specification, the NFC chip 302 and the NFC antenna 301 connected thereto may be provided by commercially available chips, such as, but not limited to, the NXP NTAG5LINK chip, the FUDAN MICRO FM11NT082C chip, and related chips from manufacturers such as ST.

[0038] In the embodiments of the present specification, considering that the user terminal equipment may be in LPCD mode, making it difficult to communicate successfully and difficult to wake up, in order to increase the success rate of communication, the energy recovered from the NFC chip 302 operating in passive mode is provided to the excitation circuit 303, and the excitation circuit 303 emits an active radio frequency field to excite the user terminal equipment, so that the user terminal equipment switches to a standard card detection mode and performs near field communication data interaction, thereby increasing the success rate of near field communication.

[0039] 2, the circuit unit 300 for realizing near field communication is provided with an excitation circuit 303. Specifically, the NFC chip 302 may be electrically connected to the excitation circuit 303, so that the NFC chip 302 can provide a portion of energy recovered by the NFC antenna 301 based on the nearby radio frequency field to the excitation circuit 303 to power the excitation circuit 303. In practical application, the NFC chip 302 can, for example, output the recovered energy to the excitation circuit 303 via a VOUT pin.

[0040] Furthermore, the NFC chip 302 may be used to obtain first energy when the NFC antenna 301 senses a radio frequency field of a user terminal device, and provide a portion of the first energy to the excitation circuit 303. The excitation circuit 303 may be used to generate and emit an excitation signal using the energy obtained from the NFC chip 302, and the excitation signal is used to excite the user terminal device to communicate with a device including the circuit unit 300.

[0041] Furthermore, in the circuit unit 300, the NFC antenna 301 may be connected to the excitation circuit 303, and the excitation circuit 303 may be used to radiate the excitation signal to the user terminal device via the NFC antenna.

[0042] In one or more embodiments herein, a communication connection may be established between the NFC chip 302 and the excitation circuit 303. Specifically, the NFC chip 302 may sense the field strength status of the user terminal device through the NFC antenna 301 and output a related signal (e.g., an interrupt signal) to the excitation circuit 303.

[0043] More specifically, the NFC chip 302 may further be used to send an interrupt signal to the excitation circuit 303 when the NFC antenna 301 senses the proximity of the radio frequency field of the user terminal equipment; accordingly, the excitation circuit 303 may specifically be used to generate and emit an excitation signal when it determines, based on the signal characteristics of the interrupt signal, that the user terminal equipment is in a low-power card detection mode, and the excitation signal is used to switch the user terminal equipment in the low-power card detection mode to a standard card detection mode.

[0044] FIG. 3 shows a detailed schematic diagram of a circuit unit 300 for realizing short-range wireless communication according to an embodiment of the present disclosure.

[0045] 3, a circuit unit 300 for realizing near field wireless communication may include an NFC antenna 301, an NFC chip 302, and an excitation circuit 303, and the excitation circuit 303 may further include a controller 3031 and a signal generator 3032. The controller 3031 detects a relevant interrupt signal and controls the signal generator 3032 to turn on field emission excitation by a hardware enable signal when the condition is required, and can further wake up the other user terminal device.

[0046] Optionally, the controller 3031 may control the signal generator 3032 to turn on the field emission excitation when it determines based on the interrupt signal that the remote user terminal device is in an LPCD state.

[0047] Specifically, the controller 3031 may be used to use energy obtained from the NFC chip 302 to determine whether the user terminal device is in a low-power card detection mode based on the signal characteristics of the interrupt signal, and to issue a hardware enable signal to the signal generator 3032 when the user terminal device is in the low-power card detection mode. Accordingly, the signal generator 3032 may be used to generate and issue the excitation signal in response to the hardware enable signal using energy obtained from the NFC chip 302.

[0048] In practical application, the NFC chip 302 may be electrically connected to the excitation circuit 303 to provide energy to the excitation circuit 303. Specifically, the NFC chip 302 may be electrically connected to the controller 3031 and the signal generator 3032 to provide energy to the controller 3031 and the signal generator 3032, respectively.

[0049] The NFC chip 302 may be communicatively connected to the excitation circuit 303 to output an interrupt signal to the excitation circuit 303. Specifically, the NFC chip 302 may be communicatively connected to the controller 3031 and output an interrupt signal to the controller 3031. Furthermore, the controller 3031 may execute a preset decision flow, and when it determines that an excitation signal needs to be emitted, output a hardware enable signal to the signal generator 3032 to cause the signal generator 3032 to emit the excitation signal.

[0050] In practical application, the NFC chip 302 and the controller 3031 may communicate with each other via a communication interface such as I2C or SPI. In specific implementation, a software program may be injected into the NFC chip 302, so that when the NFC chip 302 acquires a signal of a nearby radio frequency field based on the sensing of the NFC antenna 301, the software program may output an interrupt signal to the controller 3031, allowing the controller 3031 to understand the characteristics of the radio frequency field.

[0051] Taking the FUDAN MICRO FM11NT082C chip as an example, when the NFC chip 302 detects a change in field strength, it can output a high-level interrupt to the controller 3031 via an interrupt request (IRQ) pin to establish communication between the NFC chip 302 and the controller 3031.

[0052] Specifically, a field strength signal characteristic of the radio frequency field emitted by the user terminal device may be carried in the interrupt signal.

[0053] In practical application, the signal characteristics of the interrupt signal may include, but are not limited to, at least one of a pulse width, a time period, and a pulse amplitude. In practical application, determining whether the user terminal device is in a low-power card detection mode may specifically include determining whether the user terminal device is in a low-power card detection mode based on at least one of a pulse width, a time period, and a pulse amplitude of the interrupt signal.

[0054] Specifically, the signal characteristics of the terminal request information sent by the NFC chip 302 may be used to reflect the characteristics of the radio frequency field of the user terminal device. When the user terminal device is in different card detection states, the characteristics of the emitted radio frequency field are different, and therefore the characteristics of the interrupt signal generated by the NFC chip and sent to the controller 3031 are different.

[0055] For example, when the user terminal equipment is in the LPCD mode, the pulse width of the emitted radio frequency field signal is shorter, and the pulse width of the interrupt signal is correspondingly shorter, for example, when the user terminal equipment is in the LPCD mode, the time period of the emitted radio frequency field signal is longer, and the time period of the interrupt signal is correspondingly longer, for example, when the user terminal equipment is in the LPCD mode, the pulse amplitude of the emitted radio frequency field signal is weaker, and the pulse amplitude of the interrupt signal is correspondingly weaker, for example, when the user terminal equipment is in the LPCD mode, the pulse width of the emitted radio frequency field signal is weaker, and the pulse width of the interrupt signal is correspondingly weaker, for example, when the user terminal equipment is in the LPCD mode, the pulse width of the emitted radio frequency field signal is weaker, and the pulse width of the interrupt signal is correspondingly weaker, for example, when the user terminal equipment is in the LPCD mode, the pulse width of the emitted radio frequency field signal is weaker, and the pulse width of the interrupt signal is correspondingly weaker, for example, when the user terminal equipment is in the standard card detection ... LPCD mode, the pulse width of the emitted radio frequency field signal is weaker, and the pulse width of the interrupt signal is correspondingly weaker, for example, when the user terminal equipment is in the LPCD mode, the pulse width of the emitted radio frequency field signal is weaker, and

[0056] Furthermore, to save energy, the controller 3031 may control the signal generator 3032 to turn on the field emission excitation when it determines that the information in the NFC chip 302 has not been read.

[0057] In actual application, when communication between the NFC chip and the user terminal device is successful and the information in the NFC chip 302 is read by the user terminal device, the NFC chip will output corresponding flag bit information according to the program settings of the NFC chip. In actual application, after the controller 3031 receives an interrupt signal, it reads this flag bit information from the NFC chip through a communication interface (e.g., a communication interface such as I2C or SPI), and can further determine whether communication is successful based on this flag bit information.

[0058] Specifically, the controller 3031 may further use energy obtained from the NFC chip 302 to determine whether communication between the user terminal device and the NFC chip 302 is successful based on flag bit information obtained from the NFC chip 302, and may be used to issue a hardware enable signal to the signal generator 3032 when the user terminal device is in a low-power card detection mode and communication between the user terminal device and the NFC chip 302 is not successful. Accordingly, the signal generator 3032 may use energy obtained from the NFC chip 302 to generate and issue the excitation signal in response to the hardware enable signal.

[0059] That is, the excitation circuit 303 may specifically be used to generate and emit an excitation signal when it determines based on the signal characteristics of the interrupt signal that the user terminal equipment is in a low-power card detection mode and communication between the NFC chip and the user terminal equipment is unsuccessful.

[0060] In one or more embodiments herein, an energy recovery circuit may be further provided to further increase the efficiency of recovering the energy of the radio frequency field provided by the NFC master device operating in active mode.

[0061] FIG. 4 shows a schematic diagram of a circuit unit 310 for realizing another short-range wireless communication according to an embodiment of the present disclosure.

[0062] 4 , a circuit unit 310 for realizing near field communication may include an NFC antenna 301, an NFC chip 302, and an excitation circuit 303, and the circuit unit 310 may further include a rectifying circuit 304, which may be connected to the NFC antenna 301 and the excitation circuit 303. Specifically, the rectifying circuit 304 may be used to obtain second energy when the NFC antenna 301 senses a radio frequency field of a user terminal device, and provide at least a portion of the second energy to the excitation circuit 303.

[0063] Specifically, the 13.56 MHz sine wave sensed by the NFC antenna may be output by a rectification circuit 304 to the subsequent excitation circuit 303 for use. The rectification circuit 304 may be electrically connected to the excitation circuit 303, and more specifically, may be electrically connected to the controller 3031 and the signal generator 3032 so as to provide energy to the controller 3031 and the signal generator 3032.

[0064] In one or more embodiments herein, given that the field period of the LPCD is particularly short, an additional energy supply module may optionally be added to the excitation circuit 303 as a supplement to the emergency power supply to ensure the completion of one communication period.

[0065] FIG. 5 shows a schematic diagram of a circuit unit 320 for realizing yet another short-range wireless communication according to an embodiment of the present disclosure.

[0066] As shown in FIG. 5, a circuit unit 320 for realizing near field communication may include an NFC antenna 301, an NFC chip 302, an excitation circuit 303, and a processing circuit 304, and the circuit unit 320 may further include an energy supply module 305, which is connected to the excitation circuit 303 and is used to provide a third energy to the excitation circuit 303.

[0067] Optionally, the energy supply module 305 may be configured as a rechargeable module. When a rechargeable energy supply module 305 is installed, the energy recovered from the NFC chip 302 and the arrangement circuit 304 may be provided to the rechargeable energy supply module 305, and further provided to the excitation circuit 303 as needed, to improve energy utilization efficiency. The rechargeable energy supply module 305 may also have an external charging interface to obtain additional energy.

[0068] In practical application, the energy supply module 305 may be specifically configured as a button battery, a lithium battery, etc.

[0069] It should be noted that the solution of installing the energy supply module 305 for providing additional energy to the excitation circuit 303 in the embodiments of the present specification is different from the solution of active NFC chips in the related art. In active NFC chips in the related art, a power source is installed to directly power the NFC chip, rather than installing an additional power source to power the excitation circuit 303 after installing the excitation circuit 303. In the embodiments of the present specification, the energy supply module 305 plays the role of a power source and is used as a final solution. In other words, even if the energy supply module 305 is not used, the excitation circuit 303 can still be powered by recovering energy sensed by the NFC antenna, and the counterpart device can be woken up, thereby improving the success rate of near field wireless communication.

[0070] In one or more embodiments herein, a separate antenna may be provided to radiate the excitation signal generated by excitation circuit 303 .

[0071] FIG. 6 shows a schematic diagram of a circuit unit 330 for realizing further near field wireless communication according to an embodiment of the present disclosure.

[0072] As shown in FIG. 6 , a circuit unit 330 for realizing near field communication may include an NFC antenna 301, an NFC chip 302, and an excitation circuit 303, and the circuit unit 330 may further include a second NFC antenna 306, the second NFC antenna 306 is connected to the excitation circuit 303, and the excitation circuit 303 is used to radiate the excitation signal to the user terminal device via the second NFC antenna 306.

[0073] Unlike the embodiment shown in Fig. 2, in the embodiment shown in Fig. 6, the excitation signal may be radiated by a separately established NFC antenna. By installing a second NFC antenna 306 to radiate the excitation signal, a complex time division multiplexing design is not required, the design is simpler, and the signal emission efficiency is higher. Meanwhile, since the antenna is installed separately, compared to multiplexing the original existing antenna, the shape and position of the second NFC antenna can be more flexibly configured, which can greatly increase the radiation intensity of the excitation signal, improve inductance coupling with the counterpart user terminal device, further increase the probability of waking up the user terminal device from LPCD mode, and further improve the success rate of near field wireless communication.

[0074] As shown in Figure 6, by optimizing based on the embodiment shown in Figure 2, the excitation signal emitted through the NFC antenna 301 is changed to the excitation signal emitted through the second NFC antenna 306. Optionally, the NFC antenna 301 and the second NFC antenna 306 may emit the excitation signal together, thereby further improving the signal emission efficiency, increasing the probability of waking up the user terminal device from the LPCD mode, and further improving the success rate of near field wireless communication.

[0075] Similar improvements may be made to the embodiment shown in Figures 4 and 5, similar to the improvements to the embodiment shown in Figure 2 described above.

[0076] Specifically, the circuit unit 310 shown in FIG. 4 may be modified to further include a second NFC antenna 306, so that the excitation signal may be emitted through the second NFC antenna 306, or the excitation signal may be emitted jointly through the NFC antenna 301 and the second NFC antenna 306.

[0077] Similarly, the circuit unit 320 shown in FIG. 5 may be modified to further include a second NFC antenna 306, so that an excitation signal may be emitted through the second NFC antenna 306, or an excitation signal may be emitted jointly through the NFC antenna 301 and the second NFC antenna 306.

[0078] Based on the above description, a schematic diagram of a situation in which a circuit unit for realizing short-range wireless communication in an actual application scenario according to an embodiment of this specification and a user terminal device operating in active mode perform short-range wireless communication is shown in Figure 7.

[0079] As shown in FIG. 7 , the circuit unit may include an NFC antenna 301, an NFC chip 302, and an excitation circuit 303. Here, the excitation circuit 303 may specifically include a controller 3031 and a signal generator 3032. When a user terminal device operating in active mode approaches the NFC antenna 301, the NFC antenna 301 senses the proximity of a radio frequency field. The NFC chip 302 connected to the NFC antenna 301 can output a portion of the energy recovered from the NFC antenna 301 to the excitation circuit 303. Based on the change in the field signal sensed by the NFC antenna 301, the NFC chip 302 can generate an interrupt signal and send it to the excitation circuit 303. If the excitation circuit 303 determines that a preset condition is met based on the interrupt signal, the excitation signal can be emitted via the NFC antenna 301, facilitating the user terminal device waking up from the LPCD mode. Specifically, the excitation signal may be emitted via the NFC antenna 301, or via a second NFC antenna 306 installed separately.

[0080] Optionally, to improve the recovery rate of the radio frequency field energy emitted from the user terminal device operating in active mode, a rectification circuit 304 may be provided between the NFC antenna 301 and the excitation circuit 303. The rectification circuit 304 is used to collect the radio frequency field energy and output it to the excitation circuit 303 in the process of the NFC antenna 301 sensing the radio frequency field.

[0081] In practical application, when the NFC chip 302 and the arrangement circuit 304 are used together to recover energy, the energy recovery rate can be significantly increased. For example, in the process of the proximity of the primary radio frequency field, about 30mW to 50mW (1.8V, 16mA to 28mA) of energy can be recovered and provided to the excitation circuit 303 in the subsequent stage for use.

[0082] Furthermore, the controller 3031 may include a low-power microcontroller unit (MCU). Generally, a low-power MCU has a sleep power consumption of the uA level and an operating capability of several tens of uA at 1 MHz (e.g., Kokumin's N32L40 series, ST's related MCUs, etc.), and generally operates at about 40 MHz and can control the operating current to about 3.6 mW to 7.2 mW (1.8 V, 2 to 4 mA).

[0083] In actual application, when the NFC chip 302 cannot directly wake up the counterpart device due to a passive load change of the NFC antenna 301, causing communication to be interrupted, the energy recovered by the NFC chip 302 and the processing circuit 304 can be provided to operate the low-power MCU. Specifically, when a field signal approaches the NFC antenna 301, the NFC chip 302 and the processing circuit 310 start to recover energy and provide it to operate the low-power MCU, causing it to operate in a low-power state. After the NFC chip 302 detects that an interrupt signal is sent from the field, it wakes up the low-power MCU from the low-power state. The low-power MCU can further determine the operating state of the counterpart device from comprehensive information such as the pulse width, time period, and pulse amplitude of the interrupt signal. If it determines that the counterpart device is in the LPCD state, the low-power MCU controls the signal emitter to emit a 13.56M active field, waking up the counterpart device and completing the next communication, thereby further improving the success rate of communication.

[0084] Furthermore, the signal generator 3032 may include an active crystal or an RC oscillator circuit and is primarily used to generate a signal field of approximately 12 to 14 MHz, consuming essentially 3.6 mW to 5.4 mW (1.8 V, 2 to 3 mA). Specifically, under the control of the controller 3031, the signal generator 3032 may conduct the generated signal field to an antenna via a link and radiate it outward. Alternatively, as shown in FIGS. 2 to 5, the signal generator 3032 may conduct the signal field to the NFC antenna 301 and radiate it outward (NFC antenna 301 time division multiplexing). Alternatively, as shown in FIG. 6, the signal generator 3032 may conduct the signal field to the second NFC antenna 306 and radiate it outward.

[0085] In one or more embodiments of the present disclosure, the frequency of the active field radiated outward based on the excitation signal provided by the signal generator 3032 may be tuned to match the frequency of the radio frequency field of the user terminal device, i.e., to be a resonant multipoint. Specifically, it may be set to 12 to 14 MHz. More specifically, it may be set to about 13.56 MHz.

[0086] In one or more embodiments herein, the NFC antenna 301 in the circuit unit (including the circuit units 300, 310, 320, or 330) may be further optimized.

[0087] FIG. 8 shows a structural schematic diagram of a metal piece used in an NFC antenna according to an embodiment of the present disclosure.

[0088] In the circuit unit for realizing near field communication, the NFC antenna 301 may include a metal piece 401 shown in Fig. 8. The metal piece 401 may be curved within a plane in which the metal piece 401 is located so that both ends along the longitudinal direction of the metal piece 401 are close to each other to form a gap space.

[0089] FIG. 9 illustrates another structural schematic diagram of a metal piece used in an NFC antenna according to an embodiment of the present disclosure.

[0090] In the circuit unit for realizing near field communication, the NFC antenna 301 may include a metal piece 402 as shown in Fig. 9. Similar to Fig. 8, the metal piece 402 may be curved in a plane in which the metal piece 402 is located, so that both ends along the longitudinal direction of the metal piece 402 are close to each other to form a gap space.

[0091] 8 and 9 may be a metal piece that is curved in a plane into a loop shape, unlike the metal wire wound structure used in the conventional NFC antenna 301. In actual application, the middle area surrounded by the metal piece 401 or 402 may be used to place the NFC chip 302. The relative positions of the NFC chip 302 and the metal piece 401 or 402 are not limited to this.

[0092] 8 and 9 only show two specific examples of metal pieces, and in actual application, the shape of the metal piece is not limited to being circular or rectangular, but may be polygonal or irregular, and the curvature of the metal piece may be set according to actual needs, for example, adaptively adjusted for the spatial position where the NFC chip is attached.

[0093] Furthermore, the material of the metal piece may be a metal that is commonly used for communication antennas, such as copper.

[0094] Optionally, in practical application, a metal piece may be used as the NFC antenna instead of the metal coil. Specifically, both ends along the longitudinal direction of the metal piece may serve as power supply points for the NFC antenna 301. In practical application, the NFC antenna 301 may be connected to the NFC chip 302 through the power supply points.

[0095] Optionally, in practical application, a metal piece and a metal coil may be combined to form the NFC antenna 301. Specifically, the metal coil may include a power supply point connected to the NFC chip 302, and the metal piece may not include a power supply point.

[0096] To distinguish it from a conventional wire-shaped metal coil, in the embodiments of the present specification, the NFC antenna may be configured as a sheet-shaped metal ring having a relatively large area in the plane where the antenna body is located, thereby increasing the equivalent inductance value of the antenna, for example, to 500 nH to 2 uH. When this inductance value is matched with the capacitance to form a resonant circuit with a resonance point of about 13.56 MHz, a relatively large amount of radiation energy can be achieved, and an appropriate capacitance can be found to match it.

[0097] This can improve the ability to wake up the user terminal from an LPCD state by affecting the sensing load of the other user terminal, while also improving the efficiency of energy recovery, and further improving the strength and efficiency of radiating the excitation signal via the NFC antenna 301. Overall, this can improve the success rate of communication when an NFC device and a user terminal perform short-range wireless communication.

[0098] FIG. 10 is a schematic diagram of an NFC antenna including a metal piece and a metal coil provided by an embodiment of the present specification.

[0099] Specifically, in a circuit unit for realizing near field communication, the NFC antenna 301 includes a metal piece (for example, the metal piece 401 shown in FIG. 8 or the metal piece 402 shown in FIG. 9), and the NFC antenna 301 may further include a metal coil, which may be located in the same plane as the metal piece, and which may be located in a region surrounded by the metal piece after it is bent.

[0100] 10, the metal coil 501 may be located in the area surrounded by the bent metal piece 401. In practical application, the NFC chip 302 may also be located in the area surrounded by the metal coil 501.

[0101] FIG. 11 is a schematic diagram of an NFC antenna including another metal piece and a metal coil provided by an embodiment of the present specification.

[0102] Specifically, in a circuit unit for realizing near field communication, when the NFC antenna 301 includes a metal piece (for example, the metal piece 401 shown in FIG. 8 or the metal piece 402 shown in FIG. 9), the NFC antenna 301 may further include a metal coil, and the metal coil may be placed so as to overlap the metal piece, and the metal piece may be closer to the scanned side of the device including the circuit unit than the metal coil.

[0103] As shown in FIG. 11, the metal piece 401 may be set closer to the scanned side of the device including the circuit unit than the metal coil 501.

[0104] In practical application, in the NFC antenna module, the metal piece and the metal coil are arranged in a ferrule or overlapping manner, allowing the ring-shaped metal piece to function as an amplifier, thereby improving the signal transmission efficiency and strength, and further increasing the success rate of the user terminal device waking up from LPCD mode, thereby further increasing the success rate of near field wireless communication.

[0105] In addition, in the embodiments of the present specification, in order to better couple the NFC antenna to the antenna of the partner user terminal device, a matching circuit is installed (for example, by connecting a certain capacitance value in parallel) and the NFC antenna is tuned to the transmission frequency band of 13.56 MHz (12 to 14 MHz), thereby achieving better coupling with the antenna of the partner user terminal device and increasing energy conversion efficiency.

[0106] In one or more embodiments of the present specification, when a second NFC antenna 306 is employed in the circuit module, the second NFC antenna 306 may be a metal piece, similar to the NFC antenna 301.

[0107] Specifically, the second NFC antenna 306 included in a circuit unit for realizing near field communication may include a metal piece that is curved within a plane in which the metal piece is located so that both ends along the longitudinal direction of the metal piece are close to each other to form a gap space. For example, the metal piece may be metal piece 401 shown in Fig. 8 or metal piece 402 shown in Fig. 9, and the shape of the metal piece is not limited thereto.

[0108] Optionally, in practical application, a metal piece may be used as the NFC antenna instead of the metal coil. Specifically, both ends along the longitudinal direction of the metal piece may serve as the power supply points of the second NFC antenna 306. In practical application, the second NFC antenna 306 may be connected to the NFC chip 302 through the power supply points.

[0109] Optionally, in practical application, a metal piece and a metal coil may be combined to form the second NFC antenna 306. Specifically, the metal coil may include a power supply point connected to the NFC chip 302, and the metal piece may not include a power supply point.

[0110] Further optionally, in the circuit unit for realizing near field communication, the NFC antenna 306 may include a metal piece (for example, the metal piece 401 shown in FIG. 8 or the metal piece 402 shown in FIG. 9), and the second NFC antenna 306 may further include a metal coil, which may be located in the same plane as the metal piece, and which may be located in an area surrounded by the metal piece after bending.

[0111] 10, the metal coil 501 may be located in the area surrounded by the bent metal piece 401. In practical application, the NFC chip 302 may also be located in the area surrounded by the metal coil 501.

[0112] Furthermore, optionally, in a circuit unit for realizing near field communication, when the NFC antenna 301 includes a metal piece (for example, the metal piece 401 shown in FIG. 8 or the metal piece 402 shown in FIG. 9), the second NFC antenna 306 may further include a metal coil, which may be placed overlapping the metal piece, and which may be closer to the scanned side of the device including the circuit unit than the metal coil.

[0113] As shown in FIG. 11, the metal piece 401 may be set closer to the scanned side of the device including the circuit unit than the metal coil 501.

[0114] In practical application, in an NFC antenna module (for example, the NFC antenna 301 or the second NFC antenna 306), a metal piece and a metal coil are arranged in a ferrule or overlapping manner, allowing the ring-shaped metal piece to function as an amplifier, thereby improving the signal transmission efficiency and strength, and further increasing the success rate of the user terminal device waking up from LPCD mode, thereby further increasing the success rate of near field wireless communication.

[0115] The various technical features in the above examples can be arbitrarily combined as long as there is no conflict or contradiction between the combinations of features. Although they are not described one by one due to space limitations, any combination of the various technical features in the above embodiments also falls within the scope of disclosure of this specification.

[0116] One or more embodiments of the present specification further provide an NFC device corresponding to the circuit unit for realizing the near field communication, which may include any circuit unit according to the embodiments of the present specification described above.

[0117] Specifically, the NFC device may include a circuit unit for realizing near field communication, and the circuit unit may include an NFC antenna 301, an NFC chip 302, and an excitation circuit 303, and the NFC chip 302 is connected to the NFC antenna 302, and the NFC chip 302 is connected to the excitation circuit 303.

[0118] Here, the NFC chip 302 may be used to obtain first energy when the NFC antenna 301 senses a radio frequency field of a user terminal device, and provide a portion of the first energy to the excitation circuit.

[0119] The excitation circuit 303 may be used to generate and emit an excitation signal using energy obtained from the NFC chip 302, and the excitation signal is used to excite the user terminal device to communicate with the NFC device.

[0120] In the embodiment of the present specification, the NFC device operates in a passive mode, and the user terminal device communicating with the NFC device operates in an active mode.

[0121] It should be noted that the technical solution of this NFC device and the technical solution of the above circuit unit belong to the same concept, and for any details not described in detail in the technical solution of the NFC device, please refer to the description of the technical solution of the above circuit unit.

[0122] Each embodiment in this specification is described in a step-by-step manner, and the same or similar parts between the embodiments may be referred to. The emphasis of each embodiment is on the differences from other embodiments. Because the devices according to the embodiments of this specification include embodiments of a circuit unit for realizing short-range wireless communication, the devices also have beneficial technical effects similar to those of embodiments of a circuit unit for realizing short-range wireless communication. Since the beneficial technical effects of the embodiments of a circuit unit for realizing short-range wireless communication have been described in detail above, the beneficial technical effects of the corresponding devices will not be further described here.

[0123] The foregoing describes specific embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the examples and still achieve desirable results. Also, processes depicted in the figures do not necessarily require that the desired results be achieved only in the particular order or sequential order shown.

[0124] It should be further explained that the terms "comprise," "include," or any other variation thereof, are intended to cover the non-exclusive "comprise," whereby a process, method, or apparatus comprising a set of elements not only includes those elements, but also other elements not expressly listed, or further elements inherent in such process, method, or apparatus. In the absence of further limitations, an element qualified by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes said element.

[0125] As mentioned above, the present application is merely an example and is not intended to limit the present application. Those skilled in the art will appreciate that the present application can undergo various modifications and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included within the scope of the claims of the present application.

Claims

1. A circuit unit for realizing short-range wireless communication, an NFC antenna, an NFC chip, and an excitation circuit, wherein the NFC antenna is connected to the NFC chip, and the NFC chip is connected to the excitation circuit; the NFC chip is used to obtain first energy when the NFC antenna senses a radio frequency field of a user terminal device, and to provide a portion of the first energy to the excitation circuit; A circuit unit, wherein the excitation circuit is used to generate and emit an excitation signal using energy obtained from the NFC chip, and the excitation signal is used to excite the user terminal device to communicate with a device including the circuit unit.

2. The circuit unit according to claim 1 , wherein the NFC antenna is connected to the excitation circuit, and the excitation circuit is used to radiate the excitation signal to the user terminal device via the NFC antenna.

3. 2. The circuit unit according to claim 1, wherein the circuit unit further includes a second NFC antenna, the second NFC antenna being connected to the excitation circuit, and the excitation circuit being used to radiate the excitation signal to the user terminal device via the second NFC antenna.

4. the NFC chip is further adapted to send an interrupt signal to the excitation circuit when the NFC antenna senses a radio frequency field of the user terminal device; 2. The circuit unit according to claim 1, wherein the excitation circuit is specifically used to generate and emit an excitation signal when it determines that the user terminal equipment is in a low-power card detection mode based on the signal characteristics of the interrupt signal, and the excitation signal is used to switch the user terminal equipment in the low-power card detection mode to a standard card detection mode.

5. the excitation circuit includes a controller and a signal generator; The controller is used to use energy obtained from the NFC chip to determine whether the user terminal device is in a low-power card detection mode based on a signal characteristic of the interrupt signal, and to issue a hardware enable signal to the signal generator when the user terminal device is in the low-power card detection mode; 5. The circuit unit according to claim 4, wherein the signal generator is used to generate and emit the excitation signal in response to the hardware enable signal by utilizing energy obtained from the NFC chip.

6. 6. The circuit unit of claim 5, wherein the controller is further used to use energy obtained from the NFC chip to determine whether communication between the user terminal device and the NFC chip is successful based on flag bit information obtained from the NFC chip, and to issue a hardware enable signal to the signal generator when the user terminal device is in a low-power card detection mode and communication between the user terminal device and the NFC chip is not successful.

7. the circuit unit further includes a rectifying circuit, the rectifying circuit being connected to the NFC antenna and the excitation circuit; 2. The circuit unit according to claim 1, wherein the arranging circuit is used to obtain second energy when the NFC antenna senses a radio frequency field of a user terminal device and to provide at least a portion of the second energy to the excitation circuit.

8. The circuit unit according to claim 1 , further comprising an energy supply module, the energy supply module being connected to the excitation circuit and being used to provide a third energy to the excitation circuit.

9. 2. The circuit unit of claim 1, wherein the NFC antenna includes a metal piece that is curved within a plane in which the metal piece is located so that both ends along the longitudinal direction of the metal piece are close to each other to form a gap space.

10. The circuit unit according to claim 9 , wherein both ends of the metal piece along the longitudinal direction serve as feeding points for the NFC antenna.

11. 10. The circuit unit of claim 9, wherein the NFC antenna further includes a metal coil, the metal coil being located in the same plane as the metal piece, and the metal coil being located in a region that is surrounded by the metal piece after it is bent.

12. The circuit unit according to claim 9, wherein the NFC antenna further includes a metal coil, the metal coil being positioned so as to overlap the metal piece, and the metal piece being closer to the scanned side of the device including the circuit unit than the metal coil.

13. 4. The circuit unit of claim 3, wherein the second NFC antenna includes a metal piece that is curved within a plane in which the metal piece is located so that both ends along the longitudinal direction of the metal piece are close to each other to form a gap space.

14. The circuit unit according to claim 13 , wherein both ends of the metal piece along the longitudinal direction serve as feeding points for the second NFC antenna.

15. 14. The circuit unit of claim 13, wherein the second NFC antenna further includes a metal coil, the metal coil being located in the same plane as the metal piece, and the metal coil being located in a region that is surrounded by the metal piece after it is bent.

16. The circuit unit according to claim 13, wherein the second NFC antenna further includes a metal coil, the metal coil being positioned so as to overlap the metal piece, and the metal piece being closer to the scanned side of the device including the circuit unit than the metal coil.

17. An NFC device comprising the circuit unit according to any one of claims 1 to 16.

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