Antenna device
By designing an antenna device that includes a series capacitor voltage divider and an EMC filter, the frequency and phase balance problem of NFC devices in supporting multiple functions was solved, and stable transmission of multi-functional NFC signals and activation of antenna recognition were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-24
- Publication Date
- 2026-04-07
AI Technical Summary
Existing NFC devices struggle to support multiple near-field communication functions simultaneously, particularly in terms of frequency and phase balance management.
An antenna device including first and second antennas is used. Phase and amplitude balance is achieved through a matching circuit design of a series capacitor voltage divider and an EMC filter, and the active antenna is determined by a voltage sensor.
It achieves improved phase and amplitude balance management of NFC signals at multiple frequencies, can support multiple NFC functions simultaneously, and accurately identifies the active antenna through a voltage sensor.
Smart Images
Figure CN121814129A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an antenna device and an NFC apparatus. In particular, the present disclosure relates to an antenna device comprising a first antenna and a second antenna each configured to receive and transmit near field communication signals, and to an NFC apparatus comprising such an antenna device. BACKGROUND
[0002] The present disclosure relates to an antenna device for a near field communication apparatus (NFC apparatus). NFC is a short-range wireless technology that allows NFC-enabled devices to communicate with each other. Such devices can include mobile phones, tablets, laptops, wearable devices, and other devices. NFC technology can be used for contactless payments, data sharing, mobile ticketing and access control, among other uses. SUMMARY
[0003] According to a first aspect of the present disclosure, there is provided an antenna device comprising: a first antenna configured to receive and transmit a first set of near field communication signals; a second antenna configured to receive and transmit a second set of near field communication signals; a first transmitter path coupled to the first antenna, wherein the first transmitter path comprises a first matching circuit, and wherein the first matching circuit comprises a first series capacitor divider arranged in series with the first antenna, wherein the first antenna is coupled in series between the first matching circuit and a reference voltage node; a second transmitter path coupled to the second antenna, wherein the second transmitter path comprises a second matching circuit, and wherein the second matching circuit comprises a second series capacitor divider arranged in series with the second antenna, wherein the second antenna is coupled in series between the second matching circuit and the reference voltage node; a first receiver path coupled to the first transmitter path at a first tapping point, wherein the first tapping point is arranged between capacitors in the first series capacitor divider; a second receiver path coupled to the second transmitter path at a second tapping point, wherein the second tapping point is arranged between capacitors in the second series capacitor divider; and wherein a first node of the first antenna is coupled to an output of the first matching circuit and a second node of the first antenna is coupled to the reference voltage node; and wherein a first node of the second antenna is coupled to an output of the second matching circuit and a second node of the second antenna is coupled to the reference voltage node.
[0004] In one or more embodiments, the first matching circuit can comprise a first ground capacitor comprising a first node coupled to the first transmitter path and a second node coupled to the reference voltage node; and the second matching circuit can comprise a second ground capacitor comprising a first node coupled to the second transmitter path and a second node coupled to the reference voltage node.
[0005] In one or more embodiments, the first transmitter path can additionally comprise a first EMC filter arranged between a first end of the first transmitter path and the first matching circuit, wherein the first end of the first transmitter path is opposite a second end of the first transmitter path, and wherein the first antenna is arranged at the second end of the first transmitter path; and the second transmitter path can additionally comprise a second EMC filter arranged between a first end of the second transmitter path and the second matching circuit, wherein the first end of the second transmitter path is opposite a second end of the second transmitter path, and wherein the second antenna is arranged at the second end of the second transmitter path.
[0006] In one or more embodiments, the first EMC filter can comprise a first EMC filter capacitor comprising a first node coupled to the first transmitter path and a second node coupled to a reference voltage node; and the second EMC filter can comprise a second EMC filter capacitor comprising a first node coupled to the second transmitter path and a second node coupled to the reference voltage node.
[0007] In one or more embodiments, the antenna device can additionally comprise a voltage sensor configured to measure a voltage at the first antenna.
[0008] In one or more embodiments, the voltage sensor can be an analog input of a microprocessor configured to measure the voltage at the first antenna.
[0009] According to a second aspect of the disclosure, there is provided a near field communication (NFC) apparatus comprising the antenna device of the first aspect.
[0010] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments and methods thereof have been shown by way of example in the drawings and will be described in detail herein. It should be understood however that it is not intended to limit the disclosure to the particular embodiments described but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claims attached hereto.
[0011] The above discussion is not intended as a representation of every example embodiment or implementation of the present or future claims. The following drawings and detailed description further illustrate various example embodiments. The detailed description, considered in connection with the accompanying drawings, can enable those skilled in the art to understand the various example embodiments. BRIEF DESCRIPTION OF DRAWINGS
[0012] One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:
[0013] Figure 1 Example embodiments of the antenna device of the disclosure are shown;
[0014] Figure 2 Alternative example embodiments of the antenna device of the present disclosure are shown that additionally include a voltage sensor; and
[0015] Figure 3 An example NFC device is shown that includes the antenna device. DETAILED DESCRIPTION
[0016] In view of the widespread use of NFC in modern society, there is an increasing desire for NFC-enabled devices to be able to perform multiple functions sequentially or simultaneously. In practice, this requires the implementation of multiple antennas each configured to receive and transmit NFC signals. The present disclosure provides a front-end topology having antennas that are connected to a common reference voltage node (e.g., a ground node) along with a corresponding topology. The topology of the present disclosure can enable improved phase and amplitude balance management.
[0017] Figure 1 An example antenna device 100 according to the present disclosure is shown. The antenna device 100 includes a first antenna 101 and a second antenna 102, and supporting electronics that enable the reception and transmission of near field communication (NFC) signals.
[0018] The antenna device 100 includes a first antenna 101 configured to receive and transmit a first set of near field communication signals. The first antenna 101 is represented in Figure 1 by inductor 101. The configuration of the first antenna 101 to receive and transmit near field communication signals includes properties such as the size, conductivity, and other electrical or physical properties of the first antenna 101 that enable the first antenna 101 to function as an antenna at a desired frequency or frequencies. For example, a typical operating frequency for NFC can be approximately 13.56 MHz, however, this is not the only frequency that can be selected.
[0019] The antenna device 100 additionally includes a second antenna 102 configured to receive and transmit a second set of near field communication signals. The second antenna 102 is represented in Figure 1 by inductor 102. The configuration of the second antenna 102 to receive and transmit NFC signals can include configurations such as size, conductivity, and other electrical or physical properties that enable the second antenna 102 to function as an antenna at a desired frequency or frequencies.
[0020] The antenna device 100 additionally comprises a first transmitter path 103 and a second transmitter path 104. The transmitter paths 103, 104 comprise electronics that can couple their respective antennas 101, 102 to a transmitter arrangement (not shown) that is configured to generate signals for transmission, or can be configured to couple to a transmitter arrangement that is configured to generate signals for transmission. That is, it should be appreciated that the antenna device does not necessarily need to be coupled to a transmitter arrangement (or, as will be discussed later, a receiver arrangement) in order to provide all the core features of the present disclosure as defined in the claims. Due to this, neither the transmitter arrangement that can enable signal transmission nor the receiver arrangement that can process received signals will be discussed in detail herein. Generally, the transmitter arrangement and the receiver arrangement can be implemented as an NFC integrated circuit that is configured to generate outgoing signals and to process incoming signals. It should be appreciated that alternative implementations can also be used.
[0021] The first transmitter path 103 can comprise a first EMC filter 105. The first EMC filter 105 can enable attenuation of undesired electromagnetic interference, e.g. harmonics of the signals for transmission. That is, the first EMC filter 105 can improve the robustness of the antenna device 100 with respect to internally generated electromagnetic signals or external electromagnetic signals at frequencies for which the first EMC filter 105 is configured to attenuate. Thus, the first EMC filter 105 can allow the antenna device 100 to operate reliably.
[0022] The first EMC filter can comprise a first EMC filter inductor 106 arranged in series between a first end of the first transmitter path 103 and a first matching circuit 113, wherein the first end of the first transmitter path 103 can be configured to receive a transmission signal for transmission through the first antenna 101. That is, a first node of the first EMC filter inductor 106 can be coupled to a first node (first end) of the first transmitter path. A second node of the first EMC filter inductor 106 can be coupled to a first node of the first matching circuit, as will be described below. The second node of the first EMC filter inductor 106 can additionally be coupled to a first node of a first EMC filter capacitor 107. The first EMC filter capacitor 106 can be coupled to a reference voltage node 108, e.g. a ground node. More specifically, a second node of the first EMC filter capacitor 107 can be coupled to the reference voltage node 108, e.g. a ground node.
[0023] The second EMC filter 110 can comprise a second EMC filter inductor 111 arranged in series between a first end of the second transmitter path 104 and a second matching circuit, where the first end of the second transmitter path 104 can be configured to receive a transmit signal for transmission by the second antenna 102 and an output of the EMC filter 110. That is, a first node of the second EMC filter inductor 111 can be coupled to a first node of the second transmitter path 104. A second node of the second EMC filter inductor 111 can be coupled to a first node of the second matching circuit, as described below. The second node of the second EMC filter inductor 111 can additionally be coupled to a first node of a second EMC filter capacitor 112. The second EMC filter capacitor 112 can be coupled to the reference voltage node 108, for example a ground node, which can be the reference voltage node. More specifically, a second node of the second EMC filter capacitor 112 can be coupled to the reference voltage node 108, for example a ground node. That is, the first and second EMC filter capacitors 107, 112 can be arranged in series between the first and second transmitter paths 103, 104, and the first and second EMC filter capacitors 107, 112 can additionally comprise an intermediate reference voltage node 108 therebetween.
[0024] Any reference voltage node referred to herein can comprise a ground node set to a relative 0 volt, or can refer to a node configured to be coupled to a ground node set to a relative 0 volt in use. Such a reference voltage node referred to herein can be a ground- coupleable reference voltage node. Any reference node can be set to the same relative voltage as one or more of the other reference nodes, or one or more reference nodes can be set to a different reference voltage, as appropriate to enable operation of the antenna device in the manner described. It will be further appreciated that, generally, a reference node such as a ground node is only considered to be coupled to ground when the device is coupled to a power supply. Accordingly, a reference to a node or terminal that can be coupled to ground should be understood by the skilled person to be an explicit reference to such an amplifier circuit that does not require coupling to a power supply to act as an amplifier circuit according to the present disclosure, but is configured to be so coupled in use.
[0025] The first transmitter path 103 can additionally comprise a first matching circuit 113. The first matching circuit 113, which can be a first impedance matching circuit, can be configured to implement one or both of: compensate for an inductive impedance of the first antenna 101; and implement an impedance transformation from a load impedance to a source impedance.
[0026] The first matching circuit 113 includes a first series capacitor divider 114 arranged in series with the first EMC filter 105 and the first antenna 101. In particular, the first series capacitor divider can be arranged in series between the first EMC filter 105 and the first antenna 101. The first series capacitor divider 114 can be a series capacitor divider composed of a first series capacitor 115 and a second series capacitor 116, wherein the first series capacitor 115 is configured to receive a signal from the first EMC filter 105 at a first node. A second node of the first series capacitor 115 can be coupled to a first node of the second series capacitor 116 in the first series capacitor divider 113. A second node of the second series capacitor 116 can be coupled to a first node of the first antenna 101. The first matching circuit 113 can additionally include a first ground capacitor 117 coupled between the second node of the second series capacitor 116 and a reference voltage node 108, which can be a ground node.
[0027] The second matching circuit 123 includes a second series capacitor divider 124 arranged in series with the second EMC filter 110 and the second antenna 102. In particular, the second series capacitor divider 124 can be arranged in series between the second EMC filter 104 and the second antenna 102. The second series capacitor divider 124 can be a series capacitor divider composed of a first series capacitor 125 and a second series capacitor 126, wherein the first series capacitor 125 is configured to receive a signal from the second EMC filter 110 at a first node. A second node of the first series capacitor 125 can be coupled to a first node of the second series capacitor 126 in the second series capacitor divider 123. A second node of the second series capacitor 126 can be coupled to a first node of the second antenna 102. The second matching circuit 123 can additionally include a second ground capacitor 127 coupled between the second node of the second series capacitor 126 and the reference voltage node 108, which can be a ground node. That is, the first ground capacitor 117 and the second ground capacitor 127 of the first matching circuit 113 and the second matching circuit 123 can be arranged in series between the first transmitter path 103 and the second transmitter path 104, and the first ground capacitor 117 and the second ground capacitor 127 can additionally include an intermediate reference voltage node 108 coupled therebetween.
[0028] The first antenna 101 can be coupled to an output node of the first matching circuit 113. In particular, a first node of the first antenna 101 can be coupled to the output node of the first matching circuit 113, and a second node of the first antenna 101 can be coupled to a reference voltage node 108, e.g. a ground node. Similarly, the second antenna 102 can be coupled to an output node of the second matching circuit 123. In particular, a first node of the second antenna 102 can be coupled to the output node of the second matching circuit 123, and a second node of the second antenna 102 can be coupled to the reference voltage node 108, e.g. a ground node. The first antenna 101 and the second antenna 102 can be arranged in series between the first transmitter path 103 and the second transmitter path 104, and the first antenna 101 and the second antenna 102 comprise an intermediate reference voltage node 108 coupled therebetween.
[0029] The antenna device 100 additionally comprises a first receiver path 130 and a second receiver path 131 coupled to their respective transmitter paths 103, 104 at a first tap point 132 and a second tap point 133, respectively. While the full length of the conductor between TX1 and the first antenna is referred to herein as the first transmitter path 103, it will be appreciated that this is done for ease of reference. It will be appreciated that the received signal still travels at least a part of the “first transmitter path 103” (as referred to herein) between the first antenna and the first tap point 132. In practice, the received signal can also travel through other parts of the antenna device 100, however, the signals of interest for the receiver path 130 are those that will travel from the first antenna 101 to the first tap point 132 and from the first tap point 132 to the first end of the receiver path 130, which can be or be couplable to a receiver device. The same description can equally apply to the path travelled by signals received at the second antenna 102, which are travelled along at least a part of the first transmitter path 104.
[0030] The first receiver path can comprise a first receiver path capacitor 134 and a first receiver path resistor 135, wherein the first receiver path capacitor 134 and the first receiver path resistor 135 are coupled in series between a first end (first node) of the first receiver path 130 and the first tap point 132. The first tap point 132 is arranged between the capacitors 115, 116 in the first series capacitor voltage divider 114. That is, the first tap point 132 is arranged between the first series capacitor 115 and the second series capacitor 116 of the first matching circuit 113.
[0031] The second receiver path 131 can comprise a second receiver path capacitor 136 and a second receiver path resistor 137, wherein the second receiver path capacitor 136 and the second receiver path resistor 137 are coupled in series between a first end (first node) of the second receiver path 131 and a second tapping point 133. The second tapping point 133 is arranged between the capacitors 125, 126 in the second series capacitor voltage divider 124. That is, the second tapping point 133 is arranged between the first series capacitor 125 and the second series capacitor 126 of the second matching circuit 124.
[0032] The topology described herein can achieve maintaining approximately 180° phase difference between the first receiver path and the second receiver path. Providing a tapping point between the capacitors in the series capacitor voltage divider provides a balancing effect that allows these phase differences to be maintained with or without detuning caused by the presence of a card near the antenna.
[0033] Figure 2 An example antenna device 200 is shown in accordance with the present disclosure and with reference to Figure 1 described herein. Figure 2 The antenna device 200 depicted in the figure additionally comprises a signal sensor 201 configured to measure a signal at the first antenna 101. The signal sensor 201 can be any suitable signal sensor 201 configured to measure a signal on the first antenna 101. In one or more embodiments, the signal sensor 201 can comprise a connection of the first node of the first antenna 101 and an analog input of the integrated circuit 202, and wherein the integrated circuit 202 is configured to measure a signal or an electrical property at the first antenna 101. Thus, the signal sensor 201 can be configured to provide signaling to the integrated circuit 202 indicative of the signal at the first antenna 101. Based on the signaling, the integrated circuit 202 can be configured to determine which of the antennas 101, 102 is currently operating. It can be particularly beneficial to be able to determine a signal on one of the two antennas 101, 102, as under normal operation it can not be possible to determine which of the antennas 101, 102 is receiving a signal (has been triggered by placement). By implementing a signal measurement at one of the antennas 101, it can be possible to distinguish which of the antennas 101, 102 has been activated.
[0034] In one or more embodiments, signal sensor 201 may be a voltage sensor 201 configured to measure the voltage on first antenna 101. Voltage sensor 201 may be configured to provide signaling to integrated circuit 202 indicating the voltage at first antenna 101. Based on the signaling, integrated circuit 202 may be configured to determine which of antennas 101, 102 is currently operating. It should be understood that the signal sensor may be of a different type of signal sensor, such as a current sensor or another sensor that measures the electrical properties of the first antenna.
[0035] Figure 3 The diagram shows an antenna device 301 (e.g.) Figure 1 or Figure 2 Example of an antenna device 301) is a Near Field Communication (NFC) device 300. NFC device 300 can be any device in which two antennas may be desired. For example, NFC device 300 can be a mobile phone, tablet device, smartwatch, payment terminal, access control system, smart jewelry, wireless or binaural headphones, game console, medical device, or a type of clothing.
[0036] Those skilled in the art will understand that configuring the various components of an antenna device to operate within certain frequency / time / impedance schemes may involve scaling the components to a suitable size and adjusting inductors, capacitors, resistors, and other electrical characteristics to operate within the desired scheme. Those skilled in the art will also understand that because components of another circuit may be connected in a similar arrangement, if the components are configured for operation for different technical purposes, they may not necessarily provide the same technical effects as the circuits disclosed herein.
[0037] Unless a specific order is explicitly stated, the instructions and / or flowchart steps in the above figures may be performed in any order. Similarly, those skilled in the art will recognize that while an example set of instructions / methods has been discussed, the material in this specification can be combined in various ways to produce other examples, and should be understood within the context provided in the detailed description herein.
[0038] In some example embodiments, the instruction set / method steps described above are implemented as functional and software instructions embodied in an executable instruction set, which is implemented on a computer or machine programmed with and controlled by the executable instructions. Such instructions are loaded to execute on a processor (e.g., one or more CPUs). The term processor includes a microprocessor, microcontroller, processor module or subsystem (including one or more microprocessors or microcontrollers), or other control or computing device. A processor may refer to a single component or multiple components.
[0039] In other examples, the instruction sets / methods illustrated herein, along with their associated data and instructions, are stored in appropriate storage devices, which are implemented as one or more non-transitory machine- or computer-readable or computer-usable storage media. Such computer-readable or computer-usable storage media are considered part of an article (or article of manufacture). An article or article of manufacture may refer to any single or multiple manufactured components. Non-transitory machine- or computer-usable media as defined herein do not include signals, but such media are capable of receiving and processing information from signals and / or other transient media.
[0040] Example embodiments of the materials discussed in this specification may be implemented wholly or partially via a network, computer, or data-based device and / or service. The network, computer, or data-based device and / or service may include cloud, Internet, intranet, mobile device, desktop computer, processor, lookup table, microcontroller, consumer device, infrastructure, or other supporting devices and services. The following non-exclusive definitions are provided as may be used herein and in the claims.
[0041] In one example, automating one or more instructions or steps discussed herein. The terms automation or automaticity (and similar variations) mean controlling the operation of equipment, systems, and / or processes using computers and / or mechanical / electrical devices without human intervention, human observation, human effort, and / or human decision-making.
[0042] It should be understood that any components that are allegedly to be coupled can be coupled or connected directly or indirectly. In the case of indirect coupling, an additional component may be positioned between the two components that are allegedly to be coupled.
[0043] In this specification, exemplary embodiments have been presented based on a selected set of details. However, those skilled in the art will understand that many other exemplary embodiments, including different sets of these details, can be practiced. It is intended that the appended claims cover all possible exemplary embodiments.
Claims
1. An antenna device, characterized in that, include: A first antenna, configured to receive and transmit a first set of near-field communication signals; A second antenna, configured to receive and transmit a second set of near-field communication signals; A first transmitter path coupled to the first antenna, wherein the first transmitter path includes a first matching circuit, and wherein the first matching circuit includes a first series capacitor voltage divider arranged in series with the first antenna, wherein the first antenna is coupled in series between the first matching circuit and a reference voltage node. A second transmitter path coupled to the second antenna, wherein the second transmitter path includes a second matching circuit, and wherein the second matching circuit includes a second series capacitor voltage divider arranged in series with the second antenna, wherein the second antenna is coupled in series between the second matching circuit and the reference voltage node; A first receiver path, which is coupled to the first transmitter path at a first tap point, wherein the first tap point is arranged between capacitors in the first series capacitor divider. A second receiver path is coupled to the second transmitter path at a second tap point, wherein the second tap point is arranged between capacitors in the second series capacitor divider. and The first node of the first antenna is coupled to the output of the first matching circuit and the second node of the first antenna is coupled to the reference voltage node; and the first node of the second antenna is coupled to the output of the second matching circuit and the second node of the second antenna is coupled to the reference voltage node.
2. The antenna device according to claim 1, characterized in that: The first matching circuit includes a first ground capacitor, which includes a first node coupled to the first transmitter path and a second node coupled to the reference voltage node. and The second matching circuit includes a second ground capacitor, which includes a first node coupled to the second transmitter path and a second node coupled to the reference voltage node.
3. The antenna device according to any one of the preceding claims, characterized in that: The first transmitter path further includes a first EMC filter disposed between a first end of the first transmitter path and the first matching circuit, wherein the first end of the first transmitter path is opposite to a second end of the first transmitter path, and wherein the first antenna is disposed at the second end of the first transmitter path; and The second transmitter path further includes a second EMC filter disposed between a first end of the second transmitter path and the second matching circuit, wherein the first end of the second transmitter path is opposite to the second end of the second transmitter path, and wherein the second antenna is disposed at the second end of the second transmitter path.
4. The antenna device according to claim 3, characterized in that: The first EMC filter includes a first EMC filter capacitor, which includes a first node coupled to the first transmitter path and a second node coupled to the reference voltage node. and The second EMC filter includes a second EMC filter capacitor, which includes a first node coupled to the second transmitter path and a second node coupled to the reference voltage node.
5. The antenna device according to any one of the preceding claims, characterized in that, Additionally, a signal sensor is included, which is configured to measure the signal at the first antenna.
6. The antenna device according to claim 5, characterized in that, The signal sensor is an analog input to a microprocessor, configured to measure the signal at the first antenna.
7. A near-field communication (NFC) device, characterized in that, Including the antenna device according to any of the preceding claims.