WO2024103557A1 - 一种支持随意贴附且正面读写距离远的nfc天线 - Google Patents

一种支持随意贴附且正面读写距离远的nfc天线 Download PDF

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Publication number
WO2024103557A1
WO2024103557A1 PCT/CN2023/077592 CN2023077592W WO2024103557A1 WO 2024103557 A1 WO2024103557 A1 WO 2024103557A1 CN 2023077592 W CN2023077592 W CN 2023077592W WO 2024103557 A1 WO2024103557 A1 WO 2024103557A1
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Prior art keywords
nfc
antenna
induction coil
substrate
outer ring
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PCT/CN2023/077592
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English (en)
French (fr)
Inventor
贾晓彬
胡振华
王诗文
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时迈安拓通讯科技（苏州）有限公司
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Publication of WO2024103557A1 publication Critical patent/WO2024103557A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/06—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop with core of ferromagnetic material
    • H01Q7/08—Ferrite rod or like elongated core

Definitions

  • the present invention relates to the technical field of terminal wireless communication, and in particular to an NFC antenna that supports random attachment and has a long front reading and writing distance.
  • Wireless communication antennas will be able to provide more services in the future, such as financial transactions or other highly secure transmissions such as alarms, door opening or building access control. These types of wireless communication scenarios require very short-range communication through inductive loop antennas to prevent eavesdropping or accidental use. This type of communication is generally referred to as near-field communication (NFC) and typically operates at a frequency of 13.56MHz.
  • NFC near-field communication
  • NFC can be a passive technology, where both the power and communication response from the chipset are invoked by a remote reader device, and can be used for wireless transactions including ID cards, access keys, bank debit cards, and such devices can also be used as stickers for retail high-value products to provide security features.
  • Another form of NFC can be activated, where the NFC antenna is located inside a device such as a mobile phone, the antenna communicates, and is driven by the device software and hardware layers to provide features such as cashless transactions or other functions by providing the correct NFC response.
  • a special feature of NFC tags for sticker applications is that the device must operate normally in a single reading direction (usually the front) in different environments, and NFC stickers need to maintain a good detection distance (more than 20mm) whether attached to metal or plastic.
  • Patent CN2019210408528 discloses a miniaturized and high-performance NFC antenna, which sets a magnetic flux medium at the center of the induction coil to enhance the magnetic flux of the induction coil and increase the antenna recognition distance, achieving good results.
  • the front recognition distance is still not far enough (the sensing distance cannot reach 20mm).
  • the present invention provides a structure for a sticker-type NFC antenna, which can significantly improve the field strength in the front direction thereof, while minimizing the impact of the pasting environment on the performance.
  • the purpose of the present invention is to overcome the problems existing in the prior art and provide an NFC antenna that supports random attachment and has a long front reading and writing distance, provides an enhanced beam from the front side, and generates an electric field strength that can achieve a front reading and writing distance of more than 20mm, while minimizing the impact of the background on the performance, and the sticker maintains stable detection when attached to different materials. Measure distance.
  • a parasitic outer ring is arranged on the substrate outside the induction coil, and the two ends of the parasitic outer ring are connected through a capacitor to form an additional LC resonant radiator and couple with the induction coil and the NFC chip to enhance the field strength of the overall antenna at the working frequency.
  • a magnetic flux medium is provided at the center of the induction coil to enhance the magnetic flux of the induction coil and the parasitic outer ring, thereby increasing the antenna recognition distance.
  • the magnetic flux medium is ferrite.
  • the ferrite is a sheet-like structure that fits the substrate and is used to prevent the substrate from warping.
  • the NFC chip is fixed to the substrate by corresponding glue dispensing and sealing.
  • the front reading and writing distance of the antenna structure of the present invention is further improved to more than 20 mm, minimizing the impact of the background environment on the performance of sticker-type NFC products, ensuring stable performance when pasted on different materials, and achieving miniaturization.
  • Fig. 1 is a schematic diagram of the structure of the present invention
  • Fig. 2 is a structural diagram of the explosion structure of Fig. 1;
  • FIG3 is a return loss diagram of the antenna of the present invention.
  • FIG4 is a diagram showing the magnetic field strength of the combination of the induction coil and the ferrite at 20 mm from the front of the whole body;
  • FIG5 is a diagram showing the magnetic field strength of the combination of the induction coil, the ferrite, the parasitic outer ring and the capacitor at 20 mm from the front of the whole.
  • a parasitic outer ring 4 is provided on the substrate 1 outside the induction coil 2, and the two ends of the parasitic outer ring 4 are connected through a capacitor 5 to form an additional LC resonant radiator and couple with the induction coil 2 and the NFC chip 3.
  • the frequency of the additional LC resonant radiator is close to the target operating frequency, so as to enhance the field strength of the overall antenna at the operating frequency.
  • the shape of the induction coil 2 and the parasitic outer ring 4 can be circular, and can also be changed to closed-loop structures of various shapes according to the needs of the application.
  • a magnetic flux medium 6 is provided at the center of the induction coil 2 to enhance the magnetic flux of the induction coil 2 and the parasitic outer ring 4 and improve the antenna recognition distance.
  • the magnetic flux medium 6 is ferrite, which can minimize the impact of background materials on the antenna reading and writing distance while increasing the antenna front recognition distance.
  • the ferrite is a sheet-like structure that fits the substrate 1 and is used to prevent the substrate 1 from warping.
  • the NFC chip 3 is sealed and fixed to the substrate 1 by corresponding glue dispensing 7 .
  • FIG. 3 it is a return loss diagram of the antenna. From the perspective of S parameters, the original antenna structure (without the parasitic outer ring 4 and the capacitor 5) has only a single resonance at 13.7 MHz (generated by the separate induction coil 2 and the NFC chip 3). The newly added parasitic outer ring 4 and capacitor 5 add a second resonance (21.15 MHz) to the overall antenna through coupling with the original induction coil 2, and at the same time move the original first resonance to 13.5 MHz, thereby enhancing the electromagnetic field strength of the overall structure and further enhancing the sensing distance.
  • the magnetic field intensity at 20 mm from the front of the whole is measured by the CST microwave studio simulation software, and the magnetic field intensity is 6.9 A/m@13.56 MHz;
  • the magnetic field strength diagram at 20mm on the overall front is measured by the CST microwave studio simulation software, and the magnetic field strength is 9.1A/m@13.56MHz. After adding the parasitic outer ring 4 and capacitor 5, the magnetic field strength is strengthened, and the front reading and writing distance will be further improved.
  • the induction coil 2 plus the combination of ferrite and the parasitic outer ring 4 and capacitor 5 is used, the average reading distance when the NFC antenna is attached to different materials is as follows:

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  • Near-Field Transmission Systems (AREA)

Abstract

本发明是一种支持随意贴附且正面读写距离远的NFC天线，包括基材，所述基材上设有若干圈感应线圈，所述感应线圈两端连接相应的NFC芯片，在所述感应线圈外侧的基材上设有寄生外圈，所述寄生外圈的两端通过电容相连，形成额外的LC谐振辐射体并与感应线圈及NFC芯片互相耦合，用以增强整体天线在工作频率的场强强度。本发明天线结构的正面读写距离进一步得到提升，可超过20mm，最小化背景环境对贴纸型NFC产品性能的影响，使其粘贴在不同材料上都能保证稳定性能，并实现小型化。

Description

一种支持随意贴附且正面读写距离远的NFC天线 技术领域
本发明涉及终端无线通讯技术领域，具体涉及一种支持随意贴附且正面读写距离远的NFC天线。
背景技术
随着当前移动通信设备(例如平板电脑、笔记本电脑、智能手机和其他无线设备)技术的进步，其发展趋势是支持更多的无线标准，提供更好的数据吞吐量，同时更薄、更美观。
无线通讯天线未来能够提供更多服务，例如金融交易或其他高度安全的传输，例如警报、开门或建筑物入口控制。这些类型的无线通信场景需要通过感应环型天线进行非常短距离的通信，以防止窃听或意外使用的安全性。这种类型的通信被泛称为近场通信(NFC)，通常以13.56MHz的频率运行。
NFC可以是一种被动技术，其中来自芯片组的电源和通信响应均由远程读取器设备调用，可用于包括身份证、门禁钥匙、银行借记卡上的无线交易，而且此类设备还可以用作零售高价值产品的贴纸以提供安全功能。另一种形式的NFC可以激活，其中NFC天线位于移动手机等设备内，天线进行通信，并由设备软件和硬件层驱动，以通过提供正确的NFC响应来提供诸如无现金交易或其他功能。用于贴纸应用的NFC标签的一个特殊功能是设备必须在不同环境下在单一读取方向(通常为正面)上正常运行，无论贴在金属还是塑料上，NFC贴纸都需要保持良好的检测距离(20mm以上)。
专利CN2019210408528中公开了一种小型化且高性能NFC天线，其在感应线圈的中心处设置磁通介质，用来增强感应线圈的磁通量，提升天线被识别距离，取得了很好的效果，但是其在部分特定应用场景下(如门禁解锁)仍然存在正面识别距离不够远(达不到20mm感应距离)的情况。
针对上述问题，本发明提供一种针对贴纸型NFC天线的结构，可以显著提高其正面方向的场强，同时最大限度地减少粘贴环境对性能的影响。
发明内容
本发明的目的在于克服现有技术存在的问题，提供一种支持随意贴附且正面读写距离远的NFC天线，从前侧提供增强的波束，并且产生的电场强度能实现20mm以上正面读写距离，同时最大限度减少背景对性能的影响，并且贴纸在贴附到不同材料时保持稳定的检 测距离。
为实现上述技术目的，达到上述技术效果，本发明通过以下技术方案实现：
一种支持随意贴附且正面读写距离远的NFC天线，包括基材，所述基材上设有若干圈感应线圈，所述感应线圈两端连接相应的NFC芯片，在所述感应线圈外侧的基材上设有寄生外圈，所述寄生外圈的两端通过电容相连，形成额外的LC谐振辐射体并与感应线圈及NFC芯片互相耦合，用以增强整体天线在工作频率的场强强度。
进一步的，所述感应线圈的中心处设有磁通介质，用于增强感应线圈和寄生外圈的磁通量，提升天线被识别距离。
进一步的，所述磁通介质为铁氧体。
进一步的，所述铁氧体为与基材相贴合的片状结构，用于防止基材曲翘。
进一步的，所述NFC芯片通过相应的点胶密封固定至基材上。
本发明的有益效果是:
本发明天线结构的正面读写距离进一步得到提升，可超过20mm，最小化背景环境对贴纸型NFC产品性能的影响，使其粘贴在不同材料上都能保证稳定性能，并实现小型化。
附图说明
图1为本发明的结构示意图；
图2为图1爆炸结构结构图；
图3为本发明天线的回波损耗图；
图4为感应线圈加上铁氧体的组合在整体正面20mm处的磁场强度图；
图5为感应线圈加上铁氧体以及寄生外圈和电容的组合在整体正面20mm处的磁场强度图。
图中标号说明：1、基材，2、感应线圈，3、NFC芯片，4、寄生外圈，5、电容，6、磁通介质，7、点胶。
具体实施方式
下面将参考附图并结合实施例，来详细说明本发明。
如图1和图2所示，一种支持随意贴附且正面读写距离远的NFC天线，包括基材1，所述基材1上设有若干圈感应线圈2，所述感应线圈2两端连接相应的NFC芯片3，在所述感应线圈2外侧的基材1上设有寄生外圈4，所述寄生外圈4的两端通过电容5相连，形成额外的LC谐振辐射体并与感应线圈2及NFC芯片3互相耦合，该额外的LC谐振辐射体的频率接近于目标工作频点，用以增强整体天线在工作频率的场强强度，在本实施例中，感应线圈2和寄生外圈4的形状可为圆环形，可也根据应用场合需要改为各种形状的闭环结构。
所述感应线圈2的中心处设有磁通介质6，用于增强感应线圈2和寄生外圈4的磁通量，提升天线被识别距离。
所述磁通介质6为铁氧体，可最大化降低背景材料对天线读写距离的影响同时提升天线正面识别距离。
所述铁氧体为与基材1相贴合的片状结构，用于防止基材1曲翘。
所述NFC芯片3通过相应的点胶7密封固定至基材1上。
如图3所示，为天线的回波损耗图，从S参数来看，原有(不带寄生外圈4和电容5)的天线结构只有单一谐振，位于13.7MHz(由单独的感应线圈2和NFC芯片3产生)；新增的寄生外圈4和电容5通过和原有的感应线圈2耦合，给整体天线增加了第二谐振(21.15MHz)，同时将原有的第一谐振移到了13.5MHz，增强了整体结构的电磁场强度，进一步增强了感应距离。
如图4所示，在单独采用感应线圈2加上铁氧体的组合时，通过CST microwave studio仿真软件测得的在整体正面20mm处的磁场强度图，其磁场强度为6.9A/m@13.56MHz；
如图5所示，在采用感应线圈2加上铁氧体以及寄生外圈4和电容5的组合时，通过CST microwave studio仿真软件测得的在整体正面20mm处的磁场强度图，其磁场强度为9.1A/m@13.56MHz，加上寄生外圈4和电容5后，磁场强度得到加强，正面读写距离将得到进一步得到提升，在采用感应线圈2加上铁氧体以及寄生外圈4和电容5的组合时，将NFC天线贴附在不同的材料上时的读距均值如下表：
表中的读距数据全部合格。
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化，不受限于特定NFC产品，线圈尺寸，线圈形状，线圈与芯片的布局，产品材质等。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (5)

  1. 一种支持随意贴附且正面读写距离远的NFC天线，包括基材(1)，所述基材(1)上设有若干圈感应线圈(2)，所述感应线圈(2)两端连接相应的NFC芯片(3)，其特征在于，在所述感应线圈(2)外侧的基材(1)上设有寄生外圈(4)，所述寄生外圈(4)的两端通过电容(5)相连，形成额外的LC谐振辐射体并与感应线圈(2)及NFC芯片(3)互相耦合，用以增强整体天线在工作频率的场强强度。
  2. 根据权利要求1所述的支持随意贴附且正面读写距离远的NFC天线，其特征在于，所述感应线圈(2)的中心处设有磁通介质(6)，用于增强感应线圈(2)和寄生外圈(4)的磁通量，提升天线被识别距离。
  3. 根据权利要求2所述的支持随意贴附且正面读写距离远的NFC天线，其特征在于，所述磁通介质(6)为铁氧体。
  4. 根据权利要求3所述的支持随意贴附且正面读写距离远的NFC天线，其特征在于，所述铁氧体为与基材(1)相贴合的片状结构，用于防止基材(1)曲翘。
  5. 根据权利要求1或4所述的支持随意贴附且正面读写距离远的NFC天线，其特征在于，所述NFC芯片(3)通过相应的点胶(7)密封固定至基材(1)上。
PCT/CN2023/077592 2022-11-16 2023-02-22 一种支持随意贴附且正面读写距离远的nfc天线 WO2024103557A1 (zh)

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Citations (4)

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Publication number Priority date Publication date Assignee Title
JP2009021970A (ja) * 2007-06-11 2009-01-29 Tamura Seisakusho Co Ltd ブースターアンテナコイル
JP2011180846A (ja) * 2010-03-01 2011-09-15 Art Technology Co Ltd 非接触通信システム及びこれに用いられる誘導コイル装置
CN202404630U (zh) * 2011-12-15 2012-08-29 中国银联股份有限公司 用于近场通信的接收端组件及包括该组件的接收设备
CN210692736U (zh) * 2019-07-05 2020-06-05 时迈安拓通讯科技（苏州）有限公司 一种小型化且高性能nfc天线

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009021970A (ja) * 2007-06-11 2009-01-29 Tamura Seisakusho Co Ltd ブースターアンテナコイル
JP2011180846A (ja) * 2010-03-01 2011-09-15 Art Technology Co Ltd 非接触通信システム及びこれに用いられる誘導コイル装置
CN202404630U (zh) * 2011-12-15 2012-08-29 中国银联股份有限公司 用于近场通信的接收端组件及包括该组件的接收设备
CN210692736U (zh) * 2019-07-05 2020-06-05 时迈安拓通讯科技（苏州）有限公司 一种小型化且高性能nfc天线

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