Coupling device for near-field communication between a contactless communicating device and a radio transmitter

Abstract

The invention relates to a coupling device (10) for near-field communication between a contactless communicating device (20) and a radio transmitter (30), the device comprising: - a flexible support (11); and - an antenna (12) on the support (11). The device essentially further comprises: - positioning means for the relative positioning of the coupling device (10) with the communicating device (20) or with the transmitter (30), the relative positioning means comprising at least one from among securing means and visual referencing means, the antenna (12) of the coupling device (10) then being in a relative position such that when the near-field communication antenna of the communicating device (20) is powered by the transmitter (30), the antenna (12) of the coupling device (10) is arranged in the field lines of the contactless communicating device (20) and in the field lines of the transmitter (30).

Description

[0001] Coupling device for near-field communication between a contactless communicating device and a radiofrequency transmitter.

[0002] The present invention relates to the field of near-field communication between a contactless communicating device and a radiofrequency transmitter.

[0003] This technology is well known in banking applications. Typically, in this case, the contactless communicating device is a smart card, debit and / or credit card. The smart card is flat, has two dimensions and has four corners, in this case rounded. The format of smart cards is most often standardized.

[0004] The smart card includes a near field communication antenna.

[0005] The contactless communicating device may also take the form of an object, in particular a fashion accessory, in particular a ring.

[0006] In banking applications, the radiofrequency transmitter is, for example, a chip card reader, integrated into an Electronic Payment Terminal available in any type of business. However, with advances in technology, smartphones can also be transmitters. Unless specifically stated, the term "transmitter" here refers indiscriminately to a reader of a contactless communication device, particularly a chip card reader, or a smartphone.

[0007] The radio frequency transmitter includes a near field communication antenna.

[0008] Note that the operating principle for banking applications described below also exists for official identity documents, i.e. those issued by an authority (State, government, ministry, etc.), for example an identity card, a passport, a driving license, etc., or for unofficial identity documents, for example a subscription card, a transport card, etc., where the identity document includes a chip and a near-field communication antenna, to enable communication between the chip and a radiofrequency transmitter.

[0009] By "smart card" we therefore indistinctly mean a smart card for banking or identity applications, in particular biometric. The same applies to "contactless communicating device". Generally, the frequency of the RFID carrier between the radiofrequency transmitter and the contactless communicating device is between 13 MHz and 14 MHz, the antenna of the contactless communicating device and the antenna of the radiofrequency transmitter form two tuned resonant circuits, the resonance frequency of which is close to the carrier frequency (11-19 MHz).

[0010] To communicate in the near field between the contactless communicating device and the radiofrequency transmitter, the radiofrequency transmitter emits a magnetic field. When the contactless communicating device is in the field lines of the radiofrequency transmitter, an electric current is created in it, it is then powered by the radiofrequency transmitter, and it also emits a magnetic field. There is then a coupling between the contactless communicating device and the radiofrequency transmitter.

[0011] However, there are more and more parasitic elements that can disrupt the coupling. Even in a reader for a contactless communicating device such as an ATM in which the relative position of the contactless communicating device, in this case a smart card, and the radiofrequency transmitter is mechanically controlled, there may be field disturbing elements, for example additional magnetic fields, metallic elements or electrically conductive elements that disrupt the coupling. Likewise in a reader for a contactless communicating device such as a payment terminal, for example at a merchant's.

[0012] A fortiori when the radiofrequency transmitter is a smartphone, on the one hand the magnetic field emitted by it is generally less intense than that emitted by a smart card reader, and on the other hand, controlling the relative position of the contactless communicating device and the radiofrequency transmitter is more delicate since it is generally manual. In addition, the position of the near-field communication antenna of a smartphone is not standardized, and generally not known to its end user.

[0013] For example, the exchange of "large" data between a contactless communicating device and a reader, such as biometric data, can be compromised due to connection losses during the exchange phase. The same applies to a banking transaction.

[0014] There is therefore a need to improve the coupling between a contactless communicating device and a radiofrequency transmitter, for mechanically controlled or non-mechanically controlled applications, i.e. in a constrained environment. SUMMARY OF THE INVENTION

[0015] More specifically, the invention relates, according to a first of its objects, to a coupling device (10) for near-field communication between: a. a contactless communicating device (20) comprising a module and a near-field communication antenna (21), possibly in the form of a stand-alone module, and b. a radiofrequency transmitter (30) comprising a near-field communication antenna (31), capable of emitting a field along field lines, the coupling device (10) comprising:

[0016] - A flexible support (11),

[0017] - a near-field communication antenna (12), preferably arranged on the support (11).

[0018] It is essentially characterized in that the coupling device (10) further comprises:

[0019] - means for relative positioning of said coupling device (10) with said contactless communicating device (20) or with said radiofrequency transmitter (30), said relative positioning means comprising at least one of:

[0020] * means of solidarity, and

[0021] * visual reference means, said relative positioning means being configured to arrange the near-field communication antenna (12) of said coupling device (10) relative to the near-field communication antenna (21) of the contactless communicating device (20), respectively to the near-field communication antenna (31) of the radiofrequency transmitter (30), so that: o when the near-field communication antenna (21) of the contactless communicating device (20) is in the field of the near-field communication antenna (31) of said radiofrequency transmitter (30), then

[0022] - said near-field communication antenna (21) of the contactless communicating device (20) emits a field along field lines; and

[0023] - the near-field communication antenna (12) of the coupling device (10) is arranged both in the field lines of the contactless communicating device (20) and in the field lines of said radiofrequency transmitter (30);

[0024] - the coupling device (10) acting as a waveguide so that the coupling factor between the radiofrequency transmitter (30) and the contactless communicating device (20) is optimal. It can be provided that:

[0025] - the support (11) comprises an upper face and a lower face, at least one of which has a flat part, and

[0026] - the relative positioning means comprise securing means which comprise a set of at least one stop (15), arranged on the flat part of one or the other face of the support (11), such that the contactless communicating device (20) can come into abutment against said set of at least one stop (15).

[0027] We can predict that:

[0028] • the contactless communicating device (20) comprises a flat part comprising at least one corner, and

[0029] • the relative positioning means comprise securing means which comprise a set of at least one notch (14) in the support (11), each notch (14) being configured to be able to insert a corner of the contactless communicating device (20) therein.

[0030] It can be provided that the support (11) has two dimensions, at least one of which is greater than the smallest dimension of the contactless communicating device (20).

[0031] It can be provided that the support (11) has two dimensions, at least one of which is smaller than the smallest dimension of the contactless communicating device (20),

[0032] And that the relative positioning means comprise securing means which comprise an adhesive layer (13).

[0033] According to another of its objects, the invention relates to a contactless communicating device (20), for contactless payment or for contactless identification, comprising a module and a near-field communication antenna (21), the device having:

[0034] - in the form of a fashion accessory, in particular a piece of jewelry, and in particular a watch, a key ring, a bracelet, a pendant or a ring; or

[0035] - in the form of a smart card, in which:

[0036] • the contactless communicating device (20) comprises a coupling device (10) according to the invention, and

[0037] • the support (11) is integral with the contactless communicating device (20), with or without an adhesive layer (13). According to another of its objects, the invention relates to a radiofrequency transmitter (30) comprising a near-field communication antenna (31), capable of emitting a field along field lines, comprising a coupling device (10) according to the invention, in which: the coupling device (10) is integral with the near-field communication antenna (31) of said transmitter (30); said radiofrequency transmitter (30) being, for example, a reader of a contactless communicating device (20).

[0038] We can predict that:

[0039] - said radiofrequency transmitter (30) is a smartphone comprising a chassis (32), and

[0040] - the coupling device (10) is integral with said smartphone or said chassis (32), and when the smartphone comprises a protective shell, the coupling device (10) can optionally be integral with the protective shell.

[0041] According to another of its objects, the invention relates to a near-field communication system comprising:

[0042] • a coupling device (10) according to the invention,

[0043] • a contactless communicating device (20) for contactless payment or for contactless identification, comprising a module and a near-field communication antenna (21), and

[0044] • a display; in which: the contactless communicating device (20) is presented:

[0045] - in the form of a fashion accessory, in particular a piece of jewelry, and in particular a watch, a key ring, a bracelet, a pendant or a ring; or

[0046] - in the form of a smart card, the contactless communicating device (20) being able to comprise a coupling device (10) according to the invention, and in which: the display has a shape which locally matches that of the contactless communicating device (20), the display comprising said coupling device (10).

[0047] Finally, the invention also relates to a method for coupling near-field communication between a contactless communicating device (20) and a smartphone acting as a radiofrequency transmitter (30) comprising a near-field communication antenna (31), capable of emitting a field along field lines, by means of a coupling device (10) according to the invention, the method comprising steps consisting of:

[0048] - secure the coupling device (10) with the smartphone or with the contactless communicating device (20),

[0049] - emit a radiofrequency field through the smartphone,

[0050] - moving said smartphone and said contactless communicating device (20) in parallel planes, at a distance such that said contactless communicating device (20) is in the field lines of said smartphone,

[0051] - determining the coupling factor between said smartphone and said contactless communicating device (20) for a set of relative positions, and

[0052] - identify the relative position for which the coupling factor is maximum.

[0053] Other characteristics and advantages of the present invention will appear more clearly on reading the following description given by way of illustrative and non-limiting example and made with reference to the appended figures.

[0054] DESCRIPTION OF THE DRAWINGS

[0055] [Fig. 1] illustrates an embodiment of a coupling device according to the invention,

[0056] [Fig. 2] illustrates a method of assembling an embodiment of a device according to the invention with a smart card,

[0057] [Fig. 3] illustrates another method of assembling an embodiment of a device according to the invention with a smart card,

[0058] [Fig. 4] illustrates the relative positioning of a coupling device according to the invention when a smart card is in a smart card reader such as an ATM,

[0059] [Fig. 5A] illustrates an exploded view of a system according to the invention,

[0060] [Fig. 5B] illustrates Figure 5A in a partially exploded view.

[0061] DETAILED DESCRIPTION

[0062] Figure 1 illustrates an embodiment of a coupling device 10 according to the invention.

[0063] The device according to the invention is a coupling device 10 for near-field communication between a contactless communicating device 20, or contactless communicating object 20, and a radiofrequency transmitter 30, for example a smart card reader or a smartphone, and hereinafter “transmitter” for brevity.

[0064] The transmitter includes a near-field communication antenna 31, hereinafter referred to as "antenna" for brevity.

[0065] Typically, a contactless communicating device comes in the form of a smart card, or in the form of a fashion accessory, including jewelry, and in particular a watch, a key ring, a bracelet, a pendant or a ring.

[0066] The contactless communicating device is used for fiduciary payment purposes, for example a bank card or a payment ring etc., or for purposes of identifying its bearer, for example a badge, a subscription chip card, etc.

[0067] A smart card is flat and has two dimensions. It has four corners, most often rounded. The format of a smart card is often standardized.

[0068] The coupling device 10 according to the invention comprises a flexible support 11, preferably flat, and a near-field communication antenna, arranged on said support 11. The support 11 comprises an upper face and a lower face.

[0069] The coupling device 10 is a passive (i.e. chip-free) resonant circuit, tuned to a natural frequency, preferably between 11 MHz and 19 MHz.

[0070] The antenna 12 of the coupling device 10 is a series RLC circuit. Preferably the inductance is between 100 nH and 10 pH, and preferably 3 or 4 pH. The capacitance is between 5 pF and 300 pF, and preferably 30 pF.

[0071] In Figure 1, the coupling device 10 has a shape similar to that of a smart card meeting, for example, the ISO / IEC 7810 standards, known as ID-1. And the antenna has an oval shape. This example is illustrative and not limiting. The support 11 and the antenna can each have any type of two-dimensional shape as long as the antenna is supported by the support 11.

[0072] It is anticipated that the coupling device 10 further comprises means for relative positioning of said coupling device 10 with a contactless communicating device 20 or with a transmitter 30. These relative positioning means are configured to arrange the near-field communication antenna of said coupling device 10 in a clever relative position with respect to the antenna 21 of the contactless communicating device 20 or the antenna 31 of the transmitter 30.

[0073] Indeed, as seen previously, it happens that near-field communication between a contactless communicating device 20 and a transmitter 30 is disturbed, or even impossible.

[0074] To overcome this drawback, the coupling device 10 according to the invention acts as a waveguide between the waves of the transmitter 30 and the contactless communicating device 20.

[0075] For this purpose, it is provided that when the antenna 22 of the contactless communicating device 20 is powered by said transmitter 30, then the near-field communication antenna 12 of the coupling device 10 is arranged in the field lines of the contactless communicating device 20 and in the field lines of said transmitter 30, as illustrated in FIG. 4.

[0076] The coupling device 10 thus allows coupling between the transmitter 30 and the contactless communicating device 20, more precisely between the transmitter 30 and the coupling device 10 on the one hand, and between the coupling device 10 and the contactless communicating device 20 on the other hand.

[0077] This results in a non-zero coupling coefficient between the coupling device 10 and the contactless communicating device 20 on the one hand, and a non-zero coupling coefficient between the coupling device 10 and the transmitter 30 on the other hand.

[0078] To enable this, it is anticipated that the relative positioning means may comprise: securing means, visual reference means, or a combination of securing means and visual reference means.

[0079] The securing means comprise for example a set of at least one stop 15, arranged on one or the other face of the support 11. The stop 15 or the stops 15 may for example be embossments of the face of the support 11, for example as illustrated in Figure 3. Alternatively or in combination, the securing means may comprise a set of at least one notch 14 in the support 11, each notch 14 being configured to be able to insert therein for example a corner of a smart card, as illustrated in Figure 2.

[0080] In this case, two notches 14 are provided, allowing two adjacent corners of a smart card to be inserted.

[0081] The position of the antenna 21 of a smart card is generally known. The position of the antenna 12 of the coupling device 10 is known. It is therefore easy to position the securing means so that the antenna 12 of the coupling device 10 is in the field lines of the antenna 21 of a smart card, when the latter is powered.

[0082] The visual reference means comprise, for example, a drawing of all or part of the perimeter of a smart card, allowing a user to intuitively understand the positioning of the latter on the support 11.

[0083] Any other type of visual marker may be provided, for example a set of lines, crosses, graphic symbols (in particular arrows) etc. allowing the smart card to be positioned on the support 11.

[0084] For example, the support 11 may be in the form of a letter accompanying the supply to a user of the smart card, for example an A4 sheet comprising an antenna 12, said sheet being equipped with notches 14 and / or a visual marker (not shown) allowing the smart card to be positioned relative to the support 11 according to a predefined relative position.

[0085] In this case, the dimensions of the support 11 are greater than those of a smart card but this characteristic is not obligatory. Provided that the relative positioning allows the coupling device 10 to be in field lines of the smart card, then the support 11 can have any dimensions, including smaller than those of the smart card.

[0086] The support 11 has two dimensions, it can therefore be provided that at least one of them is greater than the smallest dimension of the smart card.

[0087] It is also possible to provide that each dimension of the support 11 is less than the smallest dimension of the smart card. In this case, it is advantageous for the relative positioning means to comprise securing means which comprise an adhesive layer 13, preferably allowing temporary securing between the coupling device 10 and the smart card, so that the flat and flexible support 11 of the coupling device 10 is stuck to one face of the smart card by said adhesive layer 13.

[0088] The coupling device 10 can thus be in the form of a self-adhesive label, arranged on one side of the chip card. Like the self-adhesive labels which protect the chip before its first use, the coupling device 10 in the form of a label can advantageously also be removed, for example once the enrollment phase is complete.

[0089] The position of the coupling device 10 on the smart card is advantageously predetermined.

[0090] It may be provided that the coupling device 10 comprises visual reference means which make it possible to position the smart card relative to these visual reference means. Alternatively or in combination, it may be provided that the smart card comprises visual reference means which make it possible to position the coupling device 10 relative to these visual reference means, for example relative to at least one edge or at least one corner of the smart card; or, if the smart card is personalized, relative to a personalization element. It may also be possible to provide ad hoc visual references on at least one of the smart card and the coupling device 10, for example lines or arrows on one face of the smart card and on the coupling device 10, said arrows having to be positioned opposite each other to obtain an optimal coupling factor.

[0091] Preferably, the connection of the coupling device 10 and the chip card is implemented during manufacturing or at the latest during personalization of the chip card, so that the end user, the holder of the chip card, receives a chip card equipped with the coupling device 10 already positioned.

[0092] However, it is also possible to provide a definitive connection between the coupling device 10 and the smart card, in particular because the manufacturer of coupling devices is often different from the manufacturer of smart cards. For this purpose, it is possible to provide that the flat and flexible support 11 is integrated into the smart card, with or without an adhesive layer 13. More generally, it is possible to provide that the coupling device 10 is integrated into the contactless communicating device 20.

[0093] Thus, it is possible to temporarily or permanently connect a coupling device 10 according to the invention and a smart card.

[0094] Similarly, a coupling device 10 according to the invention and a radiofrequency transmitter 30 can be secured, temporarily or permanently.

[0095] In a first embodiment, illustrated in FIG. 4, the radiofrequency transmitter 30 is a smart card reader, comprising a near-field communication antenna 31, housed in a plastic support 33, and which comprises a chassis 32.

[0096] In this case, the coupling device 10 is preferably glued to the support 11 of the near-field communication antenna of said smart card reader, typically in a similar manner to the embodiment in which the coupling device 10 is glued to one face of a smart card.

[0097] In this embodiment, the coupling device 10 may have any dimensions, i.e. both dimensions are greater than those of a smart card, or both dimensions are less than those of a smart card, or only one of the two dimensions is greater than one of the dimensions of a smart card.

[0098] In a second embodiment, the radiofrequency transmitter 30 is a smartphone.

[0099] A smartphone includes a 32 chassis, and often a protective shell, which protects the 32 chassis and is removable.

[0100] In this embodiment, it can be provided that the coupling device 10 is integral with said smartphone.

[0101] For example, it may be provided that the coupling device 10 is integrated into the smartphone, preferably with an adhesive layer 13. It may also be provided that the coupling device 10 is secured to the chassis 32. For example, it may be provided that the coupling device 10 is glued to the internal face or to the external face of the chassis 32, using an adhesive layer 13.

[0102] Similar to the positioning of the coupling device 10 on a smart card, the position of the coupling device 10 on the chassis 32 or in the smartphone is preferably predetermined.

[0103] When the smartphone includes a protective shell, the coupling device 10 can also be secured to the protective shell, typically glued to the internal face or to the external face of the protective shell.

[0104] For example, the shell or chassis 32 comprises visual reference means for positioning the coupling device 10, as described previously.

[0105] For the near-field communication coupling between a smart card and a transmitter using a coupling device 10 according to the invention, it is desirable that the near-field communication antenna of said coupling device 10 be in a relative position such that when the radiofrequency transmitter 30 emits a field, then the antenna of the smart card and the antenna of the coupling device 10 are arranged in the field lines of the radiofrequency transmitter 30, the antenna of the coupling device 10 also being in the field lines of the smart card.

[0106] To this end, particularly when the transmitter is a smartphone, and therefore manipulable, the following process can be provided, typically by the user of the smartphone.

[0107] First of all, it is planned to connect the coupling device 10 to the smartphone or to the smart card.

[0108] The smartphone can then emit a radiofrequency field such that the smart card and the smartphone will be able to have stable communication thanks to the coupling device 10 according to the invention which, like a waveguide, allows orientation of the electromagnetic field emitted by the smartphone.

[0109] To optimize the coupling factors, it is then planned to move said smartphone and said smart card in parallel planes, at a distance such that said smart card remains in the field lines of said smartphone, the coupling device 10 remaining integral with the smartphone or the smart card.

[0110] During this relative movement, the coupling factor between said smartphone and said smart card can be determined for a set of relative positions, for example by a software application installed on the smartphone.

[0111] It is thus possible to identify the relative position for which the coupling factor is maximum.

[0112] For example, it is possible to provide for emitting a sound or displaying a graphic representation on the smartphone display screen, the sound or the graphic representation being representative of the value of the coupling factor.

[0113] The user of the smartphone can thus very easily position the smartphone relative to the smart card thanks to the coupling device 10 which acts as a waveguide, so that the coupling factor between the smartphone and the smart card is optimal, that is to say between two predetermined values ​​around the maximum.

[0114] The coupling device 10 is not an amplifier but a waveguide which orients the field lines in the optimal position, the coupling device 10 receives both the radiofrequency field of the transmitter and the radiofrequency field of the smart card.

[0115] The invention is not limited to the embodiments previously described.

[0116] For example, the contactless communicating device 20 may be in the form of a fashion accessory, in particular a piece of jewelry, and in particular a watch, a key ring, a bracelet, a pendant or, as illustrated in FIG. 5A and FIG. 5B, in the form of a ring.

[0117] The stop principle 15 is applicable to such contactless communicating devices 20.

[0118] In Figures 5A and 5B, the contactless communicating device 20 is a ring and the transmitter 30 is a smartphone. The coupling device 10 is advantageously used for the tokenization of the ring 20 with the smartphone 30, tokenization being a method for replacing critical data with an equivalent element that will have no intrinsic value or usable meaning once it leaves the system, which in the banking field amounts to loading a set of at least one token into the ring, which can be single-use or multiple-use. If a payment takes around 300 ms with a payment ring 20, tokenization is a process that can take around 3 to 15 seconds. It is important that the relative position of the ring 20 and the smartphone 30 is stable in this interval during this tokenization operation.

[0119] For this purpose, it is advantageous to use a box 50, in particular the delivery carton in which the smartphone 30 is delivered, which includes a key, or template, for the smartphone, for example in the form of a display stand 40. An additional key for the contactless communicating device 20 can be provided, for example in the form of a recess 41 in the display stand 40, equivalent to the stops 15 previously described.

[0120] The display 40 has a front face on which the smartphone 30 is placed, and a rear face on which the coupling device 10 is arranged, for example by gluing.

[0121] Nomenclature

[0122] 10 Coupling device

[0123] 11 flat and flexible support

[0124] 12 near field communication antenna of the coupling device

[0125] 13 adhesive layer

[0126] 14 notch

[0127] 15 stop

[0128] 20 contactless communicating device

[0129] 21 near-field communication antenna of the contactless communicating device

[0130] 30 radio frequency transmitter

[0131] 31 near-field communication antenna of the radio frequency transmitter

[0132] 32 radio frequency transmitter chassis

[0133] 33 plastic support

[0134] 40 display stand

[0135] 41 display recess

[0136] 50 box set

Claims

CLAIMS Coupling device (10) for near-field communication between: a. a contactless communicating device (20) comprising a near-field communication module and antenna (21), optionally in the form of a self-contained module, and b. a radio frequency transmitter (30) comprising a near-field communication antenna (31) capable of emitting a field along field lines, the coupling device (10) comprising: A flexible support (11), a near-field communication antenna (12), preferably disposed on the support (11), characterized in that the coupling device (10) further comprises: means for relative positioning of said coupling device (10) with said contactless communicating device (20) or with said radio frequency transmitter (30), said relative positioning means comprising at least one of the following: * means of solidarity, and * visual reference means, said relative positioning means being configured to position the near-field communication antenna (12) of said coupling device (10) relative to the near-field communication antenna (21) of the contactless communicating device (20), respectively to the near-field communication antenna (31) of the radio frequency transmitter (30), such that: o when the near-field communication antenna (21) of the contactless communicating device (20) is within the field of view of the near-field communication antenna (31) of said radio frequency transmitter (30), then ■ said near-field communication antenna (21) of the contactless communicating device (20) emits a field along field lines; and ■ the near field communication antenna (12) of the coupling device (10) is disposed both in the field lines of the contactless communicating device (20) and in the field lines of said radio frequency transmitter (30); ■ the coupling device (10) acting as a waveguide so that the coupling factor between the radio frequency transmitter (30) and the contactless communicating device (20) is optimal.

2. Coupling device (10) according to claim 1, wherein: - the support (11) comprises an upper face and a lower face, at least one of which has a flat portion, and - the relative positioning means include fastening means which include a set of at least one stop (15), arranged on the flat part of one or the other face of the support (11), such that the contactless communicating device (20) can come against said set of at least one stop (15).

3. Coupling device (10) according to any one of the preceding claims, wherein: • the contactless communicating device (20) includes a flat part comprising at least one corner, and • the relative positioning means include fastening means which include a set of at least one notch (14) in the support (11), each notch (14) being configured to allow insertion of a corner of the contactless communicating device (20).

4. Coupling device (10) according to any one of the preceding claims, wherein the support (11) has two dimensions, at least one of which is greater than the smallest dimension of the contactless communicating device (20).

5. Coupling device (10) according to any one of claims 1 to 3, wherein the support (11) has two dimensions, at least one of which is smaller than the smallest dimension of the contactless communicating device (20), And in which the relative positioning means include fastening means which include an adhesive layer (13).

6. Contactless communicating device (20), for contactless payment or for contactless identification, comprising a module and a near-field communication antenna (21), the device being: - in the form of a fashion accessory, including jewelry, and in particular a watch, keychain, bracelet, pendant or ring; or - in the form of a smart card, in which: • the contactless communicating device (20) comprises a coupling device (10) according to any one of the preceding claims, and The support (11) is integral with the contactless communicating device (20), with or without an adhesive layer (13). Radio frequency transmitter (30) comprising a near-field communication antenna (31) capable of emitting a field along field lines, comprising a coupling device (10) according to any one of claims 1 to 5, wherein: the coupling device (10) is integral with the near-field communication antenna (31) of said transmitter (30); said radio frequency transmitter (30) being, for example, a reader for a contactless communicating device (20). Near-field radio frequency transmitter, wherein: - said radio frequency transmitter (30) is a smartphone comprising a chassis (32), and - The coupling device (10) is integral with said smartphone or chassis (32), and when the smartphone includes a protective case, the coupling device (10) may optionally be integral with the protective case. Near field communication system comprising: • a coupling device (10) according to any one of claims 1 to 5, • a contactless communicating device (20) for contactless payment or contactless identification, comprising a module and a near-field communication antenna (21), and • a display stand; in which: the contactless communicating device (20) is presented: - in the form of a fashion accessory, including jewelry, and in particular a watch, keychain, bracelet, pendant or ring; or - in the form of a smart card, the contactless communicating device (20) which may include a coupling device (10) according to any one of claims 1 to 5, and in which: the display has a shape which locally matches that of the contactless communicating device (20), the display comprising said coupling device (10).

10. A method for near-field communication coupling between a contactless communicating device (20) and a smartphone acting as a radio frequency transmitter (30) comprising a near-field communication antenna (31) capable of emitting a field along field lines, by means of a coupling device (10) according to any one of claims 1 to 5, the method comprising steps consisting of: - to secure the coupling device (10) to the smartphone or to the contactless communicating device (20), - emit a radio frequency field from the smartphone, - move said smartphone and said contactless communicating device (20) in parallel planes, at a distance such that said contactless communicating device (20) is within the field lines of said smartphone, - determine the coupling factor between said smartphone and said contactless communicating device (20) for a set of relative positions, and - identify the relative position for which the coupling factor is maximal.

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