WO2019167580A1 - Antenna device and nfc reader/writer - Google Patents

Antenna device and nfc reader/writer Download PDF

Info

Publication number
WO2019167580A1
WO2019167580A1 PCT/JP2019/004317 JP2019004317W WO2019167580A1 WO 2019167580 A1 WO2019167580 A1 WO 2019167580A1 JP 2019004317 W JP2019004317 W JP 2019004317W WO 2019167580 A1 WO2019167580 A1 WO 2019167580A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
antenna element
solenoid
antenna device
nfc
Prior art date
Application number
PCT/JP2019/004317
Other languages
French (fr)
Japanese (ja)
Inventor
卓 関田
Original Assignee
Ｓｍｋ−Ｌｏｇｏｍｏｔｉｏｎ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｓｍｋ−Ｌｏｇｏｍｏｔｉｏｎ株式会社 filed Critical Ｓｍｋ−Ｌｏｇｏｍｏｔｉｏｎ株式会社
Publication of WO2019167580A1 publication Critical patent/WO2019167580A1/en

Links

Images

Classifications

    • 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
    • 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 an antenna device and an NFC reader / writer that can be used for short-range wireless communication called NFC (Near Field Communication), for example.
  • NFC Near Field Communication
  • NFC can be used even when the smartphone itself does not have the NFC function. Furthermore, it has also been proposed that the SD card itself has an NFC function, and the stored contents of the SD card can be known by a smartphone (reader / writer). Conventionally, for example, an antenna described in Patent Document 1 is known as an NFC antenna. In the antenna device of Patent Document 1, a coil is wound around a core, and the direction of the lines of magnetic force is inclined by a metal body in the vicinity of the antenna device.
  • an object of the present invention is to provide an antenna device and an NFC reader / writer that are small in size and can generate a relatively strong magnetic field.
  • the present invention is, for example, A first antenna element having a first solenoid; A second solenoid element having a second solenoid and having substantially the same shape as the first antenna element; In the antenna device, the first antenna element and the second antenna element are spaced apart so that their longitudinal centers substantially coincide with each other. Further, the present invention may be an NFC reader / writer provided with such an antenna device.
  • the generated magnetic field can be strengthened by arranging the first and second antenna elements apart from each other.
  • the contents of the present invention are not construed as being limited by the effects exemplified in the present specification.
  • FIG. 1 is a layout diagram illustrating a configuration example of an antenna device according to an embodiment of the present invention.
  • FIG. 2A is a more detailed view of the antenna element according to the embodiment, and FIG. 2B is a partially enlarged view of the solenoid according to the embodiment.
  • FIG. 3A is a cross-sectional view of the antenna element according to the embodiment, and FIG. 3B is a cross-sectional view of the antenna element in another example.
  • FIG. 4 is a graph showing a change in magnetic field according to a separation distance between antenna elements in the antenna device according to the embodiment.
  • FIG. 5 is a graph showing a change in magnetic field depending on a separation distance between antenna elements in the antenna device according to the embodiment.
  • FIG. 6 is a graph illustrating a magnetic field change with respect to a change in the distance in the Z-axis direction of the antenna device according to the embodiment.
  • each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and a plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. ⁇ 1.
  • One Embodiment> [Example of overall configuration and use of antenna device] As shown in FIG.
  • an antenna element 1 as a first antenna element and an antenna element 11 as a second antenna element are arranged apart from each other.
  • the antenna elements 1 and 11 are mounted on a printed circuit board (not shown).
  • the longitudinal direction of the antenna elements 1 and 11 is defined as the X axis
  • the direction orthogonal to the X axis is defined as the Y axis
  • the height direction thereof is defined as the Z axis.
  • Both antenna elements 1 and 11 have a length of Lx.
  • the central axis in the longitudinal direction of the antenna element 1 and the central axis in the longitudinal direction of the antenna element 11 substantially coincide with each other, and the distance between the ends of both antenna elements, that is, the separation distance is substantially equal to the length Lx of both antenna elements. It is said that.
  • the resonance frequencies of the antenna elements 1 and 11 are set to be approximately equal to the NFC carrier frequency. That is, the antenna device 100 according to the present invention can be used as an antenna device of an NFC reader / writer.
  • the antenna elements 1 and 11 are connected in parallel, and a transmission signal in which a carrier signal is modulated by transmission data is transmitted from the antenna device 100 to the RF tag.
  • a signal from the RF tag is received by the antenna device, and reception is demodulated to obtain received data.
  • a relatively strong magnetic field can be generated and stable transmission / reception can be performed.
  • the antenna device 100 is disposed at a predetermined position in a case (case) of a smartphone, for example.
  • the antenna device 100 is disposed in the vicinity of a corner on a surface of a smartphone where a display is provided.
  • the user performs NFC by bringing the location where the antenna device 100 is disposed into contact with or in proximity to the corresponding device (referred to as contact or the like as appropriate).
  • the antenna element 1 includes, for example, a solenoid 3 in which an electric wire is wound in a hollow shape.
  • the solenoid 3 is wound around, for example, a prismatic magnetic body 2 having a rectangular cross section.
  • the magnetic body 2 is a ferrite with high permeability and low loss.
  • the magnetic body 2 is not limited to a prismatic shape, and may have an arbitrary shape such as a columnar shape.
  • the solenoid 3 may be an air-core coil that does not have the magnetic body 2. However, since the inductance of the solenoid 3 can be increased by the magnetic body 2, it is preferable that the solenoid 3 has the magnetic body 2.
  • the solenoid 3 has six electric wires having a line width of 0.05 mm, for example, copper wires arranged in parallel, and each electric wire is wound in parallel for a predetermined number of times (for example, 20 times). It is a turn.
  • electrode plates 4a (first electrode part) and 4b (second electrode part) made of, for example, copper are provided, respectively.
  • Six electric wires on one end side of the solenoid 3 are connected to the electrode plate 4a, and six electric wires on the other end side of the solenoid 3 are connected to the electrode plate 4b.
  • the electrode plates 4a and 4b are provided on a printed circuit board (not shown).
  • Feed electrodes 5a and 5b constituting a parallel two-wire cable are connected to the electrode plates 4a and 4b, respectively, and power is fed from the end of the parallel two-wire cable.
  • the power supply electrodes 5a and 5b are provided on a printed circuit board (not shown).
  • a capacitor 6 is connected between the power supply electrodes 5a and 5b.
  • the capacitor 6 is for resonance.
  • the other antenna element 11 has a magnetic body 2, a solenoid 3 wound around the magnetic body 2, electrode plates 4 a and 4 b provided at both ends of the solenoid 3, an electrode plate 4 a and Power supply electrodes 5a and 5b connected to 4b are provided.
  • the dimensions of the magnetic body 2 and the solenoid 3, the number of windings and the winding direction of the solenoid 3 are substantially the same between the antenna elements 1 and 11.
  • the antenna elements 1 and 11 are fed with a signal in the same phase as shown by a solid line, or fed with a signal in the opposite phase as shown by a broken line.
  • Lx 12.6 mm.
  • FIG. 3A shows a cross section of the antenna element 1 (the same applies to the antenna element 11).
  • the antenna elements 1 and 11 have a predetermined inductance assuming transmission / reception of the NFC carrier frequency (13.56 MHz), but may be other values.
  • the ground plate 7 may be arranged with an interval g of 0.2 mm, for example, with respect to the antenna element 1.
  • the ground plate 7 is a housing of a device (for example, a smartphone) to which the antenna device 100 is applied, for example.
  • the separation distance between the antenna elements 1 and 11 is set equal to the length Lx of the antenna elements 1 and 11.
  • FIG. 4 shows the measurement results.
  • the horizontal axis in FIG. 4 is the distance displaced in the axial direction of the antenna elements 1 and 11 with one end of the antenna element 1 (the end not facing the antenna element 11) as a reference (0).
  • the intensity of the magnetic field when the value of n is changed to 1, 2, 3 is represented by change curves L1, L2, L3.
  • the value of the horizontal axis x is assumed to be approximately 0 to 40 mm.
  • the magnetic field strength when the value of n is changed to 1, 2, 3 is represented as change curves L1, L2, L3.
  • the distance between the antenna elements 1 and 11 is set to the length Lx of the antenna elements 1 and 11. It has been confirmed that it is optimal to be approximately equal. Note that “substantially equal” means that an error is allowed to such an extent that the operational effects of the present invention are not achieved (for example, a decrease in magnetic field strength due to deviation is within a threshold). The same applies to the description of “almost”. ⁇ 2. Modification> As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to embodiment mentioned above, Various deformation

Landscapes

  • Near-Field Transmission Systems (AREA)
  • Details Of Aerials (AREA)

Abstract

Provided is an antenna device comprising: a first antenna element having a first solenoid; and a second antenna element having a second solenoid and having approximately the same shape as that of the first antenna element, wherein the first antenna element and the second antenna element are spaced from each other with the centers in the longitudinal direction thereof being approximately aligned with each other.

Description

アンテナ装置及びＮＦＣリーダライターAntenna device and NFC reader / writer
　本発明は、例えばＮＦＣ（Ｎｅａｒ　Ｆｉｅｌｄ　Ｃｏｍｍｕｎｉｃａｔｉｏｎ）と呼ばれる短距離無線通信で使用できるアンテナ装置及びＮＦＣリーダライターに関する。 The present invention relates to an antenna device and an NFC reader / writer that can be used for short-range wireless communication called NFC (Near Field Communication), for example.
　近年、スマートフォンがＮＦＣ機能を有し、ＮＦＣ機能を備える機器同士を近付けて通信を行うことが知られている。例えばスマートフォンを使用した決済サービスが知られている。電磁誘導方式では、キャリア周波数（１３．５６ＭＨｚ（メガヘルツ））の周波数帯において、リーダライターのアンテナからの電磁波を、ＲＦタグ側のアンテナで受けてＲＦタグの電力を発生するようになされる。これらのアンテナとして、平面状のループアンテナが使用されている。
　また、マイクロＳＤカードにＮＦＣ通信とセキュアエレメントを搭載して、決済機能以外にも身分証や鍵などをＳＤカードを通して利用することが提案されている。かかるＮＦＣ機能を有するＳＤカードの内部にアンテナを設け、かかるＳＤカードを例えばスマートフォンに装着すれば、そのスマートフォン自身がＮＦＣ機能を有しない場合にも、ＮＦＣを利用することが可能となる。さらに、ＳＤカード自身がＮＦＣ機能を有し、スマートフォン（リーダライター）によって当該ＳＤカードの記憶内容を知ることを可能とすることも提案されている。
　従来では、ＮＦＣ用のアンテナとして例えば特許文献１に記載のものが知られている。特許文献１のアンテナ装置は、コアにコイルが巻かれており、アンテナ装置の近傍の金属体によって磁力線の方向を傾けるようになされている。 In recent years, it has been known that smartphones have an NFC function and perform communication by bringing devices having the NFC function close to each other. For example, a payment service using a smartphone is known. In the electromagnetic induction method, in the frequency band of the carrier frequency (13.56 MHz (megahertz)), electromagnetic waves from the reader / writer antenna are received by the antenna on the RF tag side to generate power of the RF tag. As these antennas, planar loop antennas are used.
In addition, it has been proposed that NFC communication and a secure element are mounted on a micro SD card so that an ID card, a key, and the like can be used through the SD card in addition to the payment function. If an antenna is provided inside the SD card having the NFC function and the SD card is attached to, for example, a smartphone, NFC can be used even when the smartphone itself does not have the NFC function. Furthermore, it has also been proposed that the SD card itself has an NFC function, and the stored contents of the SD card can be known by a smartphone (reader / writer).
Conventionally, for example, an antenna described in Patent Document 1 is known as an NFC antenna. In the antenna device of Patent Document 1, a coil is wound around a core, and the direction of the lines of magnetic force is inclined by a metal body in the vicinity of the antenna device.
特許第４８８３２０８号公報Japanese Patent No. 4883208
　スマートフォン、ＳＤカード等にアンテナを内蔵する場合には、小型で且つ磁界が強いことが望まれる。特許文献１に記載の構成では、通信距離が長い場合や、移動中などで通信距離が変化する状況では、磁界の強度が不十分な場合があった。
　したがって、本発明の目的の一つは、小型で、比較的強い磁界を発生することができるアンテナ装置及びＮＦＣリーダライターを提供することにある。 When an antenna is built in a smartphone, an SD card or the like, it is desired that the antenna is small and has a strong magnetic field. In the configuration described in Patent Document 1, the strength of the magnetic field may be insufficient when the communication distance is long or when the communication distance changes due to movement or the like.
Accordingly, an object of the present invention is to provide an antenna device and an NFC reader / writer that are small in size and can generate a relatively strong magnetic field.
　本発明は、例えば、
　第１のソレノイドを有する第１のアンテナ素子と、
　第２のソレノイドを有し、前記第１のアンテナ素子とほぼ同一形状を有する第２のアンテナ素子と
　を有し、
　前記第１のアンテナ素子と前記第２のアンテナ素子とが、長手方向の中心がほぼ一致する状態で離間して配置されている
　アンテナ装置である。
　また、本発明は、かかるアンテナ装置を備えたＮＦＣリーダライターでも良い。 The present invention is, for example,
A first antenna element having a first solenoid;
A second solenoid element having a second solenoid and having substantially the same shape as the first antenna element;
In the antenna device, the first antenna element and the second antenna element are spaced apart so that their longitudinal centers substantially coincide with each other.
Further, the present invention may be an NFC reader / writer provided with such an antenna device.
　本発明によれば、第１及び第２のアンテナ素子が離間して配列されたことによって、発生する磁界を強くすることができる。なお、本明細書において例示された効果により本発明の内容が限定して解釈されるものではない。 According to the present invention, the generated magnetic field can be strengthened by arranging the first and second antenna elements apart from each other. The contents of the present invention are not construed as being limited by the effects exemplified in the present specification.
　図１は、本発明の実施形態にかかるアンテナ装置の構成例を示す配置図である。
　図２Ａは実施形態にかかるアンテナ素子のより詳細な図であり、図２Ｂは実施形態にかかるソレノイドの一部拡大図である。
　図３Ａは実施形態にかかるアンテナ素子の断面図であり、図３Ｂは他の例におけるアンテナ素子の断面図である。
　図４は、実施形態にかかるアンテナ装置において、アンテナ素子間の離間距離による磁界変化を示すグラフである。
　図５は、実施形態にかかるアンテナ装置において、アンテナ素子間の離間距離による磁界変化を示すグラフである。
　図６は、実施形態にかかるアンテナ装置のＺ軸方向の距離の変化に対する磁界変化を示すグラフである。 FIG. 1 is a layout diagram illustrating a configuration example of an antenna device according to an embodiment of the present invention.
FIG. 2A is a more detailed view of the antenna element according to the embodiment, and FIG. 2B is a partially enlarged view of the solenoid according to the embodiment.
FIG. 3A is a cross-sectional view of the antenna element according to the embodiment, and FIG. 3B is a cross-sectional view of the antenna element in another example.
FIG. 4 is a graph showing a change in magnetic field according to a separation distance between antenna elements in the antenna device according to the embodiment.
FIG. 5 is a graph showing a change in magnetic field depending on a separation distance between antenna elements in the antenna device according to the embodiment.
FIG. 6 is a graph illustrating a magnetic field change with respect to a change in the distance in the Z-axis direction of the antenna device according to the embodiment.
　以下、本発明の実施形態等について図面を参照しながら説明する。説明は以下の順序で行う。
＜１．一実施形態＞
＜２．変形例＞
　但し、以下に示す実施形態等は、本発明の技術思想を具体化するための構成を例示するものであって、本発明は例示された構成に限定されるものではない。なお、特許請求の範囲に示される部材を、実施形態の部材に特定するものではない。特に、実施形態に記載されている構成部材の寸法、材質、形状、その相対的配置、上下左右等の方向の記載等は特に限定する旨の記載がない限りは、本発明の範囲をそれのみに限定する趣旨ではなく、単なる説明例にすぎない。なお、各図面が示す部材の大きさや位置関係等は、説明を明確にするため誇張していることがあり、また、図示が煩雑となることを防止するために、参照符号の一部のみを図示する場合もある。さらに以下の説明において、同一の名称、符号については同一もしくは同質の部材を示しており、重複する説明を適宜省略する。さらに、本発明を構成する各要素は、複数の要素を同一の部材で構成して一つの部材で複数の要素を兼用する態様としてもよいし、逆に一つの部材の機能を複数の部材で分担して実現することもできる。
＜１．一実施形態＞
［アンテナ装置の全体構成例と使用例］
　図１に示すように、一実施形態にかかるアンテナ装置１００では、第１のアンテナ素子であるアンテナ素子１及び第２のアンテナ素子であるアンテナ素子１１がに離間して配置される。アンテナ素子１及び１１は、プリント回路基板（不図示）上に実装されている。アンテナ素子１及び１１の長手方向をＸ軸として、Ｘ軸と直交する方向（アンテナ素子１及び１１の幅方向）をＹ軸とし、これらの高さ方向をＺ軸とする。アンテナ素子１及び１１は、共にＬｘの長さを有する。アンテナ素子１の長手方向の中心軸とアンテナ素子１１の長手方向の中心軸がほぼ一致し、且つ両アンテナ素子の端部間距離、即ち、離間距離が両アンテナ素子の長さＬｘとほぼ等しい値とされている。
　例えば、アンテナ素子１及び１１の共振周波数がＮＦＣのキャリア周波数とほぼ等しい値とされている。即ち、本発明によるアンテナ装置１００は、ＮＦＣのリーダライターのアンテナ装置として使用できる。アンテナ素子１及び１１が並列に接続され、送信データによってキャリア信号が変調された送信信号がアンテナ装置１００からＲＦタグに対して送信される。また、ＲＦタグからの信号がアンテナ装置によって受信され、受信が復調されて受信データが得られる。リーダライターのアンテナ装置１００として使用した時に、比較的強い磁界を発生することができ、安定した送受信を行うことができる。
　アンテナ装置１００は、例えばスマートフォンの筐体（ケース）内の所定位置に配置される。一例として、スマートフォンにおけるディスプレイが設けられた面のコーナ付近にアンテナ装置１００が配置される。ユーザは、アンテナ装置１００が配置された箇所を、対応機器に接触若しくは近接（適宜、接触等と称する）させることによりＮＦＣを行う。ＮＦＣを行う際に接触等させる箇所は、アンテナ装置１００が配置された位置を基準として、所定の範囲内となるように設定されている。
［アンテナ素子の構成例］
　次に、アンテナ素子１及び１１の構成例について説明する。本実施形態では、アンテナ素子１及び１１はほぼ同一形状を有しているので、以下ではアンテナ素子１について主に説明する。
　アンテナ素子１は、図１、図２Ａ及び図２Ｂに示すように、例えば、電線が中空状に巻回されたソレノイド３を有している。ソレノイド３は、例えば矩形の断面を有する角柱状の磁性体２の周囲に巻き付けられている。磁性体２は、高透磁率で、低損失のフェライトである。磁性体２は、角柱状に限らず、円柱状などの任意の形状とすることができる。さらに、ソレノイド３は、磁性体２を有しない空芯コイルであってもよい。但し、磁性体２によってソレノイド３のインダクタンスを大きくすることができるので、ソレノイド３は、磁性体２を有する構成の方が好ましい。
　図２Ｂに示すように、ソレノイド３は、線幅が例えば０．０５ｍｍのような電線、例えば、銅線を６本平行に配し、各電線を所定回数（例えば２０回）、並列して巻回したものである。ソレノイド３の両端には、例えば銅からなる電極板４ａ（第１電極部）及び４ｂ（第２電極部）がそれぞれ設けられている。ソレノイド３の一端側の６本の電線が電極板４ａと接続され、ソレノイド３の他端側の６本の電線が電極板４ｂと接続される。電極板４ａ及び４ｂは、プリント回路基板（不図示）上に設けられている。複数本の電線を使用してソレノイド３を構成することにより、ソレノイド３の抵抗成分を減少させることができる。但し、複数本の電線を使用せずに、１本の電線を使用したソレノイド３であってもよい。
　電極板４ａ及び４ｂに対して平行２線ケーブルを構成する給電電極５ａ及び５ｂがそれぞれ接続され、平行２線ケーブルの端部から給電がなされる。給電電極５ａ及び５ｂは、プリント回路基板（不図示）上に設けられている。給電電極５ａ及び５ｂの間にキャパシタ６が接続される。キャパシタ６は、共振用のものである。
　他方のアンテナ素子１１もアンテナ素子１と同様に、磁性体２と、磁性体２に対して巻き付けられたソレノイド３と、ソレノイド３の両端に設けられた電極板４ａ及び４ｂと、電極板４ａ及び４ｂと接続された給電電極５ａ及び５ｂを有する。磁性体２及びソレノイド３の寸法、ソレノイド３の巻回数及び巻回方向がアンテナ素子１及び１１間でほぼ同一とされている。アンテナ素子１及び１１に対して図１において、実線で示すように、同相で信号が給電されるか、又は破線で示すように、逆相で信号が給電される。
　一例として、Ｌｘ＝１２．６ｍｍとなされる。図３Ａは、アンテナ素子１（アンテナ素子１１も同様）の断面を示している。アンテナ素子１の高さＨｚ＝０．９４ｍｍ、幅Ｗｙ＝０．７８５ｍｍとされる。これらの数値は、ＮＦＣのキャリア周波数（１３．５６ＭＨｚ）の送受信を想定してアンテナ素子１及び１１が所定のインダクタンスを持つようにした数値例であるが、他の値としてもよい。また、図３Ｂに示すように、アンテナ素子１に対して例えば０．２ｍｍの間隔ｇでもって、接地板７を配するようにしてもよい。接地板７は、例えば、アンテナ装置１００が適用される機器（例えば、スマートフォン）の筐体である。
［アンテナ素子間の離間距離と特性］
　本実施形態では、アンテナ素子１及び１１間の離間距離をアンテナ素子１及び１１の長さＬｘと等しいものに設定している。ここで、離間距離をＬｘ×ｎ（ｎ＝１，２，３）と変化させた場合の磁界の強度を測定した。一例として、アンテナ素子１及び１１に対してそれぞれ１Ｖの振幅を有する（１３．５６ＭＨｚ）の信号を供給した。
　図４は、測定結果を示している。図４における横軸は、アンテナ素子１の一方の端部（アンテナ素子１１とは対向していない方の端部）を基準（０）として、アンテナ素子１及び１１の軸方向に変位させた距離ｘを示している。従って、例えば、アンテナ素子１及び１１間の離間距離の中央では、ｘ＝１８．９ｍｍ（１２．６＋１２．６／２）となる。一方、図４における縦軸は、Ｚ＝５０ｍｍの位置で測定された磁界の強度を示す。ｎの値を１，２，３と変化させた場合の磁界の強度が変化曲線Ｌ１，Ｌ２，Ｌ３により表わされている。
　機器を接触等させるＮＦＣの場合のユースケースを考慮すると、横軸ｘの値は、およそ０~４０ｍｍが想定される。この間では、（ｎ＝１）の場合の変化曲線Ｌ１がもっとも磁界の強度が大きくなることが確認された。
　図５は、縦軸を、Ｚ＝８０ｍｍの位置で測定された磁界の強度とするグラフである。図４と同様に、ｎの値を１，２，３と変化させた場合の磁界の強度が変化曲線Ｌ１，Ｌ２，Ｌ３として表されている。Ｚが大きくなることで、磁界の強度自体は、図４に示す場合に比べて全体に低下する。しかしながら、この場合でも、（ｎ＝１）の場合の変化曲線Ｌ１が最も磁界の強度が大きくなることが確認された。
　図６は、縦軸を磁界の強度とし、横軸をＺ方向の距離で示したグラフである。図４及び図５と同様に、ｎの値を１，２，３と変化させた場合の磁界の強度が変化曲線Ｌ１，Ｌ２，Ｌ３として表されている。上述したように、機器を接触等させるＮＦＣのユースケースを考慮すると、Ｚの値としては、０~５０ｍｍ程度が想定される。Ｚ＝０~５０ｍｍ程度の範囲では、（ｎ＝１）が他の（ｎ＝２）及び（ｎ＝３）に比して磁界の強度が最大となることが確認された。
　以上から、使用してＮＦＣ等の短距離無線通信を行う場合、本実施形態にかかるアンテナ装置１００の構成としては、アンテナ素子１及び１１間の離間距離をアンテナ素子１及び１１の長さＬｘとほぼ等しくすることが最適であることが確認された。なお、ほぼ等しいとは、本発明の作用効果を奏さない程度（例えば、ずれによる磁界の強度の低下が閾値以内）の誤差を許容することを意味する。他の「ほぼ」との記載についても同様である。
＜２．変形例＞
　以上、本発明の実施形態について具体的に説明したが、本発明は、上述した実施形態に限定されるものではなく各種の変形が可能である。
　上述の実施形態及び変形例において挙げた構成、方法、工程、形状、材料及び数値などはあくまでも例に過ぎず、必要に応じてこれと異なる構成、方法、工程、形状、材料及び数値などを用いてもよく、公知のもので置き換えることも可能である。また、実施形態及び変形例における構成、方法、工程、形状、材料及び数値などは、技術的な矛盾が生じない範囲において、互いに組み合わせることが可能である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The description will be made in the following order.
<1. One Embodiment>
<2. Modification>
However, the following embodiments and the like exemplify a configuration for embodying the technical idea of the present invention, and the present invention is not limited to the illustrated configuration. In addition, the member shown by a claim is not specified as the member of embodiment. In particular, the scope of the present invention is limited to the dimensions, materials, shapes, relative arrangements, descriptions of directions such as up, down, left and right, etc., unless otherwise specified. It is not intended to be limited to, but merely an illustrative example. It should be noted that the size and positional relationship of the members shown in each drawing may be exaggerated for clarity of explanation, and only part of the reference numerals are used to prevent the illustration from becoming complicated. It may be illustrated. Further, in the following description, the same name and reference sign indicate the same or the same members, and a duplicate description is omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and a plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.
<1. One Embodiment>
[Example of overall configuration and use of antenna device]
As shown in FIG. 1, in an antenna device 100 according to an embodiment, an antenna element 1 as a first antenna element and an antenna element 11 as a second antenna element are arranged apart from each other. The antenna elements 1 and 11 are mounted on a printed circuit board (not shown). The longitudinal direction of the antenna elements 1 and 11 is defined as the X axis, the direction orthogonal to the X axis (the width direction of the antenna elements 1 and 11) is defined as the Y axis, and the height direction thereof is defined as the Z axis. Both antenna elements 1 and 11 have a length of Lx. The central axis in the longitudinal direction of the antenna element 1 and the central axis in the longitudinal direction of the antenna element 11 substantially coincide with each other, and the distance between the ends of both antenna elements, that is, the separation distance is substantially equal to the length Lx of both antenna elements. It is said that.
For example, the resonance frequencies of the antenna elements 1 and 11 are set to be approximately equal to the NFC carrier frequency. That is, the antenna device 100 according to the present invention can be used as an antenna device of an NFC reader / writer. The antenna elements 1 and 11 are connected in parallel, and a transmission signal in which a carrier signal is modulated by transmission data is transmitted from the antenna device 100 to the RF tag. In addition, a signal from the RF tag is received by the antenna device, and reception is demodulated to obtain received data. When used as an antenna device 100 of a reader / writer, a relatively strong magnetic field can be generated and stable transmission / reception can be performed.
The antenna device 100 is disposed at a predetermined position in a case (case) of a smartphone, for example. As an example, the antenna device 100 is disposed in the vicinity of a corner on a surface of a smartphone where a display is provided. The user performs NFC by bringing the location where the antenna device 100 is disposed into contact with or in proximity to the corresponding device (referred to as contact or the like as appropriate). A location to be contacted or the like when performing NFC is set to be within a predetermined range with reference to a position where the antenna device 100 is disposed.
[Configuration example of antenna element]
Next, a configuration example of the antenna elements 1 and 11 will be described. In the present embodiment, since the antenna elements 1 and 11 have substantially the same shape, the antenna element 1 will be mainly described below.
As shown in FIGS. 1, 2A, and 2B, the antenna element 1 includes, for example, a solenoid 3 in which an electric wire is wound in a hollow shape. The solenoid 3 is wound around, for example, a prismatic magnetic body 2 having a rectangular cross section. The magnetic body 2 is a ferrite with high permeability and low loss. The magnetic body 2 is not limited to a prismatic shape, and may have an arbitrary shape such as a columnar shape. Further, the solenoid 3 may be an air-core coil that does not have the magnetic body 2. However, since the inductance of the solenoid 3 can be increased by the magnetic body 2, it is preferable that the solenoid 3 has the magnetic body 2.
As shown in FIG. 2B, the solenoid 3 has six electric wires having a line width of 0.05 mm, for example, copper wires arranged in parallel, and each electric wire is wound in parallel for a predetermined number of times (for example, 20 times). It is a turn. At both ends of the solenoid 3, electrode plates 4a (first electrode part) and 4b (second electrode part) made of, for example, copper are provided, respectively. Six electric wires on one end side of the solenoid 3 are connected to the electrode plate 4a, and six electric wires on the other end side of the solenoid 3 are connected to the electrode plate 4b. The electrode plates 4a and 4b are provided on a printed circuit board (not shown). By configuring the solenoid 3 using a plurality of wires, the resistance component of the solenoid 3 can be reduced. However, the solenoid 3 using one electric wire may be used without using a plurality of electric wires.
Feed electrodes 5a and 5b constituting a parallel two-wire cable are connected to the electrode plates 4a and 4b, respectively, and power is fed from the end of the parallel two-wire cable. The power supply electrodes 5a and 5b are provided on a printed circuit board (not shown). A capacitor 6 is connected between the power supply electrodes 5a and 5b. The capacitor 6 is for resonance.
Similarly to the antenna element 1, the other antenna element 11 has a magnetic body 2, a solenoid 3 wound around the magnetic body 2, electrode plates 4 a and 4 b provided at both ends of the solenoid 3, an electrode plate 4 a and Power supply electrodes 5a and 5b connected to 4b are provided. The dimensions of the magnetic body 2 and the solenoid 3, the number of windings and the winding direction of the solenoid 3 are substantially the same between the antenna elements 1 and 11. In FIG. 1, the antenna elements 1 and 11 are fed with a signal in the same phase as shown by a solid line, or fed with a signal in the opposite phase as shown by a broken line.
As an example, Lx = 12.6 mm. FIG. 3A shows a cross section of the antenna element 1 (the same applies to the antenna element 11). The antenna element 1 has a height Hz = 0.94 mm and a width Wy = 0.785 mm. These numerical values are numerical examples in which the antenna elements 1 and 11 have a predetermined inductance assuming transmission / reception of the NFC carrier frequency (13.56 MHz), but may be other values. Further, as shown in FIG. 3B, the ground plate 7 may be arranged with an interval g of 0.2 mm, for example, with respect to the antenna element 1. The ground plate 7 is a housing of a device (for example, a smartphone) to which the antenna device 100 is applied, for example.
[Distance between antenna elements and characteristics]
In the present embodiment, the separation distance between the antenna elements 1 and 11 is set equal to the length Lx of the antenna elements 1 and 11. Here, the magnetic field strength was measured when the separation distance was changed to Lx × n (n = 1, 2, 3). As an example, a signal (13.56 MHz) having an amplitude of 1 V was supplied to the antenna elements 1 and 11, respectively.
FIG. 4 shows the measurement results. The horizontal axis in FIG. 4 is the distance displaced in the axial direction of the antenna elements 1 and 11 with one end of the antenna element 1 (the end not facing the antenna element 11) as a reference (0). x is shown. Therefore, for example, x = 18.9 mm (12.6 + 12.6 / 2) at the center of the separation distance between the antenna elements 1 and 11. On the other hand, the vertical axis in FIG. 4 indicates the strength of the magnetic field measured at a position of Z = 50 mm. The intensity of the magnetic field when the value of n is changed to 1, 2, 3 is represented by change curves L1, L2, L3.
Considering the use case in the case of NFC in which equipment is brought into contact, the value of the horizontal axis x is assumed to be approximately 0 to 40 mm. During this period, it was confirmed that the change curve L1 in the case of (n = 1) has the largest magnetic field strength.
FIG. 5 is a graph in which the vertical axis represents the strength of the magnetic field measured at a position of Z = 80 mm. Similar to FIG. 4, the magnetic field strength when the value of n is changed to 1, 2, 3 is represented as change curves L1, L2, L3. As Z increases, the intensity of the magnetic field itself decreases as compared to the case shown in FIG. However, even in this case, it was confirmed that the change curve L1 in the case of (n = 1) has the largest magnetic field strength.
FIG. 6 is a graph in which the vertical axis represents the magnetic field strength and the horizontal axis represents the distance in the Z direction. Similar to FIGS. 4 and 5, the magnetic field strength when the value of n is changed to 1, 2, 3 is represented as change curves L1, L2, L3. As described above, in consideration of an NFC use case in which a device is brought into contact, the value of Z is assumed to be about 0 to 50 mm. In the range of Z = 0 to 50 mm, it was confirmed that (n = 1) has the maximum magnetic field strength compared to the other (n = 2) and (n = 3).
From the above, when performing short-range wireless communication such as NFC using the antenna device 100 according to the present embodiment, the distance between the antenna elements 1 and 11 is set to the length Lx of the antenna elements 1 and 11. It has been confirmed that it is optimal to be approximately equal. Note that “substantially equal” means that an error is allowed to such an extent that the operational effects of the present invention are not achieved (for example, a decrease in magnetic field strength due to deviation is within a threshold). The same applies to the description of “almost”.
<2. Modification>
As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to embodiment mentioned above, Various deformation | transformation are possible.
The configurations, methods, steps, shapes, materials, numerical values, and the like given in the above-described embodiments and modifications are merely examples, and different configurations, methods, steps, shapes, materials, numerical values, etc. are used as necessary. It may be replaced with a known one. In addition, the configurations, methods, processes, shapes, materials, numerical values, and the like in the embodiments and the modifications can be combined with each other as long as no technical contradiction occurs.
１・・・第１のアンテナ素子、２・・・磁性体、３・・・ソレノイド、４ａ、４ｂ・・・電極板、５ａ、５ｂ・・・給電電極、１１・・・第２のアンテナ素子、１００・・・アンテナ装置 DESCRIPTION OF SYMBOLS 1 ... 1st antenna element, 2 ... Magnetic body, 3 ... Solenoid, 4a, 4b ... Electrode plate, 5a, 5b ... Feed electrode, 11 ... 2nd antenna element , 100 ... Antenna device

Claims (6)

  1. 　第１のソレノイドを有する第１のアンテナ素子と、
    　第２のソレノイドを有し、前記第１のアンテナ素子とほぼ同一形状を有する第２のアンテナ素子と
    　を有し、
    　前記第１のアンテナ素子と前記第２のアンテナ素子とが、長手方向の中心がほぼ一致する状態で離間して配置されている
    　アンテナ装置。     A first antenna element having a first solenoid;
    A second solenoid element having a second solenoid and having substantially the same shape as the first antenna element;
    The antenna device, wherein the first antenna element and the second antenna element are spaced apart with their longitudinal centers substantially coincident with each other.
  2. 　前記第１のアンテナ素子と前記第２のアンテナ素子との離間距離が、前記第１及び第２のアンテナ素子のそれぞれの長さとほぼ等しくされている
    　請求項１に記載のアンテナ装置。     The antenna apparatus according to claim 1, wherein a distance between the first antenna element and the second antenna element is substantially equal to a length of each of the first and second antenna elements.
  3. 　前記第１のソレノイドは、複数の電線が並列して巻回された構成を有し、各電線の両端が第１の電極部に接続されており、
    　前記第２のソレノイドは、複数の電線が並列して巻回された構成を有し、各電線の両端が第２の電極部に接続されている
    　請求項１又は２に記載のアンテナ装置。     The first solenoid has a configuration in which a plurality of electric wires are wound in parallel, and both ends of each electric wire are connected to the first electrode part,
    The antenna device according to claim 1, wherein the second solenoid has a configuration in which a plurality of electric wires are wound in parallel, and both ends of each electric wire are connected to the second electrode portion.
  4. 　前記第１のアンテナ素子は、前記電線が巻回された第１の磁性体を有し、
    　前記第２のアンテナ素子は、前記電線が巻回された第２の磁性体を有する
    　請求項３に記載のアンテナ装置。     The first antenna element has a first magnetic body around which the electric wire is wound,
    The antenna device according to claim 3, wherein the second antenna element includes a second magnetic body around which the electric wire is wound.
  5. 　前記第１及び第２のアンテナ素子の共振周波数がＮＦＣのキャリア周波数とほぼ等しい値とされている
    　請求項１から４までの何れかに記載のアンテナ装置。     The antenna device according to any one of claims 1 to 4, wherein a resonance frequency of the first and second antenna elements is substantially equal to an NFC carrier frequency.
  6. 　請求項１から５までの何れかに記載のアンテナ装置を備えたＮＦＣリーダ／ライター。 An NFC reader / writer comprising the antenna device according to any one of claims 1 to 5.
PCT/JP2019/004317 2018-02-27 2019-01-31 Antenna device and nfc reader/writer WO2019167580A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018-033094 2018-02-27
JP2018033094A JP2019149676A (en) 2018-02-27 2018-02-27 Antenna device and nfc reader writer

Publications (1)

Publication Number Publication Date
WO2019167580A1 true WO2019167580A1 (en) 2019-09-06

Family

ID=67805290

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2019/004317 WO2019167580A1 (en) 2018-02-27 2019-01-31 Antenna device and nfc reader/writer

Country Status (2)

Country Link
JP (1) JP2019149676A (en)
WO (1) WO2019167580A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013179866A1 (en) * 2012-05-28 2013-12-05 株式会社村田製作所 Antenna device and wireless communication device
WO2017022511A1 (en) * 2015-07-31 2017-02-09 株式会社村田製作所 Feeding coil, antenna device, and electronic apparatus
JP2017204675A (en) * 2016-05-09 2017-11-16 スミダコーポレーション株式会社 Antenna unit and door handle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013179866A1 (en) * 2012-05-28 2013-12-05 株式会社村田製作所 Antenna device and wireless communication device
WO2017022511A1 (en) * 2015-07-31 2017-02-09 株式会社村田製作所 Feeding coil, antenna device, and electronic apparatus
JP2017204675A (en) * 2016-05-09 2017-11-16 スミダコーポレーション株式会社 Antenna unit and door handle

Also Published As

Publication number Publication date
JP2019149676A (en) 2019-09-05

Similar Documents

Publication Publication Date Title
JP4720348B2 (en) Antenna for RF-ID reader / writer device, RF-ID reader / writer device using the antenna, and RF-ID system
CN106299706B (en) Antenna assembly and wireless communication device
JP2010200309A (en) Proximity antenna and wireless communication device
KR20170005670A (en) Wiress antenna for wireless charging and nfc communication, and wireless device having the same
JPWO2013035713A1 (en) Antenna device and communication terminal device
JP5950549B2 (en) Antenna device, communication device
JP2010219652A (en) Antenna device
CN108352608B (en) Antenna device for HF and LF operation
JP2014200086A (en) Antenna device
CN108292561B (en) Voltage and current compensation in inductive power transfer units
KR20170129086A (en) Wiress antenna for wireless charging and nfc communication, and wireless device having the same
EP2933878B1 (en) Antenna device
CN105493346A (en) Antenna device and communication device
WO2019167580A1 (en) Antenna device and nfc reader/writer
JP6217006B2 (en) Magnetic material loaded antenna
US10396463B2 (en) Antenna device
JP2009152714A (en) Rfid antenna and method for manufacturing antenna coil
JP6638254B2 (en) Antenna equipment and electronic equipment
JP6762692B2 (en) Antenna device
JP5673262B2 (en) Non-contact IC card reader
JP6173588B2 (en) Antenna device
JP4952439B2 (en) ANTENNA DEVICE AND WIRELESS COMMUNICATION SYSTEM
KR20220114860A (en) Coil having structure for minimizing influence thereon by metal material and resonant circuit comprising the same
JP6648793B2 (en) Vibrating antenna device and communication device
US11329380B2 (en) Configurable multiband wire antenna arrangement and design method thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19761581

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19761581

Country of ref document: EP

Kind code of ref document: A1