Near-field communication metal card

Abstract

The invention relates to a near-field contactless smart card, the card comprising a card body (10) having at least one metallic layer (110), a first antenna layer and a second antenna layer; a chip (11) disposed facing an opening (112) in the metallic layer, with a first antenna (121) formed on a surface of the first antenna layer (120) and connected to the chip (11), and a passive electronic component (12), with a second antenna (131) formed on a surface of the second antenna layer (130) and electronically connected to the component (12). Figure for the abstract: Fig. 1

Description

Title of the invention: Near-field communication metal card Technical field of the invention

[0001] The invention relates to a near-field communication card, also noted as "NFC" for "Near Field Communication". Near-field communication is a wireless communication technology that enables data exchange between two separate devices at a short distance, generally a few centimeters. NFC is commonly used in various devices such as smartphones, credit cards, and other compatible devices to perform contactless payments, share information, or establish instant connections with other NFC objects.

[0002] The present invention here relates to a card, such as a debit card, a credit card, an identification card, a loyalty card, a membership card, a health care card, a security card, etc.

[0003] The invention relates more particularly to a metallic card, that is to say to a card comprising a body including a metallic substrate. State of the art

[0004] The market for so-called "smart" cards is imposing more and more aesthetic constraints, particularly with regard to "NFC RFID" smart cards, i.e. NFC cards with RFID ("Radio Frequency Identification") chip, contactless, operating in most cases in a frequency range of approximately 13.56 MHz, for example for banking, transport, automotive or identification applications.

[0005] A metallic card here means a card whose substrate, which constitutes a substantial part of the card body, comprises, depending on its thickness, at least one metallic sheet, or is essentially made up of a metallic sheet or plate, which can be machined, engraved, painted and / or varnished as required.

[0006] The card considered here is a so-called "smart card", which therefore incorporates a metal structure in its design.

[0007] A metallic card thus presents challenges in terms of near field communication, because the presence of metal can alter the performance of an antenna contained generally in the body of the card to establish contactless, near field communication.

[0008] Consequently, special technical solutions, such as specific antennas and adapted manufacturing processes, are developed to provide a The card functions acceptably despite the presence of metal in its body.

[0009] One of the main current applications relates to metallic smart boards as described above, which may further include at least one passive electronic component, for example such as an LED (Light Emitting Diode), an OLED (Organic Light Emitting Diode), in particular an LED or an OLED connected to a diode bridge, a diode bridge, a piezoelectric component at least partly made of ceramic, a screen, a sensor, or the like.

[0010] This type of card is designed to meet specific aesthetic and functional requirements in the context of contactless NFC RFID applications.

[0011] An objective of the present invention is therefore to provide a metallic card capable of operating without contact, and which may also include at least one passive electronic component, for example as mentioned above. Description of the invention

[0012] To this end, according to a first aspect of the invention, a metallic smart card configured to operate contactless in the near field is proposed, the card comprising:

[0013] - a map body formed by a stacking of layers, the stacking of layers including at least:

[0014] - a metallic layer, the metallic layer being delimited by an edge peripheral defining a perimeter of the card body, and the metallic layer having an opening formed at a distance from the peripheral edge;

[0015] - a first antenna layer disposed on a first side of the metallic layer, distinct from the metallic layer,

[0016] - a second antenna layer, distinct from the first antenna layer and the metallic layer,

[0017] - a chip, positioned facing the opening of the metallic layer,

[0018] - a first antenna formed on a surface of the first antenna layer (120), the first antenna being electronically connected to the chip (11), the first antenna having at least one first set of turns comprising at least one so-called outer turn running along the periphery of the card body (10), and the first antenna having at least one second set of turns comprising at least one so-called inner turn surrounding the chip, or even surrounding the opening of the metal layer, the first set of turns of the first antenna being distinct from the second set of turns of the first antenna, and the first set of turns of the the first antenna being electrically connected to the second set of turns of the first antenna by at least one section of antenna wire,

[0019] - a passive electronic component,

[0020] - a second antenna formed on a surface of the second antenna layer, the second antenna being electronically connected to the passive electronic component, the second antenna having at least a first set of turns including at least one so-called external turn along the perimeter of the card body, the first set of turns of the second antenna being positioned opposite the first set of turns of the first antenna, and the second antenna having at least a second set of turns including at least one so-called internal turn surrounding the chip, or even surrounding the opening of the metal layer, the second set of turns of the second antenna being positioned opposite the second set of turns of the first antenna, the first set of turns of the second antenna being distinct from the second set of turns of the second antenna, and the first set of turns of the second antenna being electrically connected to the second set of turns of the second antenna by at least one section of antenna wire.

[0021] The card according to the invention includes in particular an additional layer comprising an antenna electrically connected to a passive electronic component, such as an LED or an OLED, optionally connected to a diode bridge, a ceramic piezoelectric component, a screen, a sensor or other.

[0022] The invention thus proposes a metallic NFC card structure comprising an HF (high frequency) RFID antenna, suitable for HF RFID applications as defined by the ISO 10373 / 14443 / 15693 communication protocol or any other HF RFID near field communication scheme.

[0023] The invention thus proposes an antenna arrangement adapted to contactless metallic NFC RFID smart cards, capable of operating in the frequency range of approximately 13.56 MHz, for example for banking (payment), transport, automotive or identification applications.

[0024] The card according to the invention is particularly suitable for purely contactless NFC metal cards and dual NFC metal cards.

[0025] Such a metallic card makes it possible to dispense with ferrite material to constitute the metallic layer.

[0026] Such a card also allows symmetrical behavior on both sides of the card while including a passive electronic component.

[0027] Each antenna comprises two sets of turns.

[0028] A set of turns comprises, for example, at least two turns, the at least two turns being separated from each other by a distance called "inter-turn distance".

[0029] Moreover, for each antenna, the first set of turns is separated from the second set of turns by a distance called "inter-set distance", which is greater than the "inter-turn distance".

[0030] For example, the innermost turn among the turns of the first set of turns is distant, by the inter-set distance, from the outermost turn among the turns of the second set of turns.

[0031] The two sets of turns of an antenna are thus visually quite distinct.

[0032] An antenna comprising two sets of turns makes it possible to capture eddy current energy from the metallic layer, thus improving a symmetrical behavior of the card in the magnetic field.

[0033] Eddy currents circulating in closed loops, the outermost loop (i.e. the largest loop), corresponding to the longest path of the eddy currents, is then the most dominant loop in terms of the energy it carries.

[0034] An advantage of a two-antenna assembly in a card according to the invention is that a current induced in the first antenna powers the chip, and a current induced in the second antenna powers the passive electronic component.

[0035] In one embodiment, the card includes at least one electrically insulating layer.

[0036] For example, the electrically insulating layer is disposed between the metallic layer and at least one of the first antenna layer and the second antenna layer.

[0037] In one embodiment, the metallic layer is arranged between the first antenna layer and the second antenna layer.

[0038] In one embodiment, the second antenna layer is arranged between the first antenna layer and the metallic layer.

[0039] In one embodiment, the passive electronic component is opposite the chip.

[0040] In one embodiment, the passive electronic component is offset laterally with respect to the opening.

[0041] In one embodiment, the card comprises a non-magnetic dielectric material.

[0042] For example, the non-magnetic dielectric material fills the opening.

[0043] In one embodiment, the metallic layer includes at least one first slot extending between the opening and a peripheral edge of the metallic layer.

[0044] For example, an edge of the first slot connects a periphery of the opening to the peripheral edge of the metallic layer.

[0045] In one embodiment, the metallic layer has at least one second slot.

[0046] For example, the second slot is blind.

[0047] For example, the second slot extends into the metal layer from the opening of the metal layer.

[0048] In one embodiment, the card includes a module inserted in a cavity of the card body.

[0049] For example, the module includes the chip.

[0050] In one embodiment, the card includes at least one top coating layer.

[0051] In one embodiment, the card includes at least one lower coating layer.

[0052] For example, the two antenna layers and the metallic layer are arranged between the upper coating layer and the lower coating layer.

[0053] In one embodiment, the passive electronic component comprises an LED, an OLED, an LED or OLED connected to a diode bridge, a ceramic piezoelectric component, a screen, or a sensor. Brief description of the figures

[0054] The invention, according to an exemplary embodiment, will be better understood and its advantages will become more apparent upon reading the following detailed description, given by way of example and in no way limiting, with reference to the accompanying drawings in which:

[0055] [Fig.1] represents a schematic cross-sectional view of a metal card according to an example of an embodiment of the present invention;

[0056] [Fig.2] schematically illustrates a top view of a metallic layer assembled with a first antenna layer of a card as illustrated in [Fig.1];

[0057] Figure 3 schematically illustrates a top view of a second antenna of a map as illustrated in [Fig.1];

[0058] Fig. 4 illustrates an arrangement in which a second antenna layer is arranged between a first antenna layer and a metallic layer, and in which the metallic layer has a so-called "central" opening;

[0059] Figure 5 illustrates an arrangement in which a second antenna layer is arranged between a first antenna layer and a metallic layer, and in which the metallic layer has an opening for a module for a "dual" type card;

[0060] Figure 6 illustrates an arrangement in which a metallic layer is disposed between a first antenna layer and a second antenna layer, and in which the metallic layer has a so-called "central" opening;

[0061] Figure 7 illustrates an arrangement in which a metallic layer is disposed between a first antenna layer and a second antenna layer, and in which the metallic layer has an opening for a module for a "dual" type card; and

[0062] Figure 8 illustrates a functional schematic representation of the map according to an example of realization of the invention. Detailed description

[0063] Fig. 1 schematically illustrates a "smart" NFC 1 metallic card structure according to an example embodiment.

[0064] A map 1 such as that considered here comprises at least one body 10, which is formed of a stack of layers. The body 10 has dimensions (length Lo, width La, thickness ep, the thickness ep being orthogonal to the length Lo and the width La shown schematically [Fig.2]) which define the dimensions of the map 1.

[0065] As it is a metallic card, the body 10 has at least one metallic layer 110.

[0066] The metallic layer 110 can here be made of any metallic material, which may not be ferritic.

[0067] For example, the metallic layer may comprise copper, aluminum, gold, stainless steel or any other material plated by a metallic coating of the aforementioned type.

[0068] The metallic layer has a peripheral edge 111 (illustrated [Fig.2]), which thus defines a perimeter (or lateral surface) of the card body.

[0069] The metallic layer 110 has a width La and a length Lo, taken along its peripheral edge 111, which define the width and length of the body 10 of card 1, and therefore incidentally the corresponding dimensions of card 1.

[0070] The metallic layer thus covers an entire surface of the card.

[0071] The metallic layer comprises a first face and a second, opposite face one to the other and essentially parallel to the other.

[0072] The first face and the second face thus define between them a thickness epm of the metallic layer (illustrated [Fig.l]).

[0073] As shown in [Fig.1], the card body further comprises a first antenna layer 120.

[0074] The first antenna layer 120 is distinct from the metallic layer 110.

[0075] The first antenna layer 120 is disposed on one side of the first face of the metallic layer 110.

[0076] In the diagram of [Fig.1], the first antenna layer 120 is arranged above the metal layer 110.

[0077] The card body further comprises a second antenna layer 130.

[0078] The second antenna layer 130 is distinct from the first antenna layer 120 and the metallic layer 110,

[0079] The second antenna layer 130 is here arranged on one side of the second face of the metallic layer 110.

[0080] In the diagram of [Fig.1], the second antenna layer 130 is arranged below the metallic layer 110.

[0081] However, as described later, the first antenna layer 120 and the second antenna layer 130 can be arranged on the same side of the metal card 110.

[0082] The card body also includes here an upper coating layer (often referred to as overlay) 161 and a lower coating layer (overlay) 162.

[0083] Overlays are layers generally arranged on the free surface of the card body.

[0084] Overlays are generally added to the card for aesthetic printing and / or security features (identification and / or authentication of a card in relation to its holder), well known in the smart card industry.

[0085] Here, the two antenna layers 120, 130 and the metal layer 110 are therefore arranged between the upper coating layer 161 and the lower coating layer 162.

[0086] At least one of the upper coating layer 161 and of the lower coating layer 162 is, for example, a plastic layer, or, for example, both coating layers 161, 162 are plastic.

[0087] According to an illustrated option [Fig.1], the card body further comprises at least one electrically insulating layer 140, 150.

[0088] Such an electrically insulating layer 140, 150 is disposed between the metallic layer 110 and the first antenna layer 120 and / or the second antenna layer 130.

[0089] Such an electrically insulating layer 140, 150 forms a protective layer and is configured to improve adhesion between the metallic layer 110 and one of the antenna layers 120, 130.

[0090] The electrically insulating layer 140, 150 comprises, for example, a layer of resin or an adhesive, for example, a layer of dielectric resin.

[0091] A dielectric resin allows the metallic layer to be attached to its adjacent upper and lower layers.

[0092] Here, an electrically insulating layer 150 is disposed between the metallic layer 110 and the first antenna layer 120, and another electrically insulating layer 140 is disposed between the metallic layer 110 and the second antenna layer 130.

[0093] Fig. 2 schematically illustrates, in top view, the metallic layer 110, assembled with the first antenna layer 120.

[0094] As shown in this figure, the metallic layer has an opening 112.

[0095] The opening 112 is formed at a distance from the peripheral edge 111 of the metallic layer 110.

[0096] The opening 112 can have any type of shape; it can have a regular shape such as a rectangle, a circle, or any other geometric shape, regular or irregular. It is generally round or rectangular, or even square. The opening may also optionally have rounded corners.

[0097] The opening can be formed in a central part of the card (as illustrated in Figures 2, 4, 6 and 8 for example), or be eccentric (as illustrated in Figures 5 and 7 for example), particularly in the case of a so-called "dual" card.

[0098] In a configuration where the opening is centered, a center of the opening is preferably located at the geometric center of the card 1, as for example provided in the EMVCO standards; for ID1 cards, the geometric center is considered as the central reference of a test plane.

[0099] The opening can, however, be offset along the length and / or width of the card. It can coincide with the cavity of the dual module. This is of particular interest because the modules can take several irregular shapes. The size of the cavity can be considerably reduced to a cavity of 1 cm in diameter (smaller than an "M3" module, an M3 module designating a small module format, for example, whose dimensions are on the order of 11 + / -0.2 mm x 82 + / -0.2 mm, for example 10.85 mm*8.17 mm).

[0100] In an embodiment of a dual card, that is to say, one that can operate with or without contact, the card then includes an electronic module embedded in a cavity of the card, and this cavity can then possibly coincide with the opening of the metallic layer, that is to say, be provided opposite the opening 112.

[0101] Such a module, then comprising chip 11, being known from the field of dual cards, it is not described in more detail here.

[0102] For example, for a dual card, a cavity is first formed in the metallic layer, then it is assembled with the other layers, then a cavity is drilled in these other layers to join the cavity of the metallic layer and insert the module into it.

[0103] In one embodiment, the card may include a non-magnetic dielectric material 116 which may be used to fill the opening 112.

[0104] This material may comprise a resin, for example the same resin as that constituting at least one electrically insulating layer 140, 150.

[0105] The non-magnetic dielectric material 116 may include a mechanically stiffening material, such as for example a ceramic, stone, wood, or rubber, for example a hard rubber.

[0106] The non-magnetic dielectric material 116 can also be transparent, for example by using tempered glass or a transparent polycarbonate filling material.

[0107] In this embodiment example, the metallic layer 110 further comprises a first slot 113.

[0108] The first slot 113 here connects the opening 112 with the peripheral edge 111 of the metallic layer.

[0109] Thus, the peripheral edge 111, the edges of the first slot 113 and a perimeter of the opening 112 form a lateral surface of the metallic layer 110 which is continuous.

[0110] For example, the first slot 113 opens at the peripheral edge 111 to an opening 114.

[0111] For example, the first slot 113 opens into the opening 112 at a mouth 115.

[0112] The mouth 114 can for example be offset relative to the mouth 115, relative to an edge of the metallic layer comprising the mouth 114.

[0113] In one embodiment, the first slot 113 may include a straight section and / or a curved section.

[0114] In the embodiment example of [Fig.2], the first slot 113 has a first section including the mouth 114 which extends orthogonally to a part of the peripheral edge 111 which includes the mouth 114.

[0115] In the embodiment example of [Fig.2], the first slot 113 has a second section having the mouth 115 which extends obliquely with respect to the first section.

[0116] Here, the first section and the second section are straight.

[0117] However, at least one of the sections could be curved.

[0118] For example, in the embodiment examples of Figures 4 and 6 described later, the first slot 113 has only a straight section, extending orthogonally to an edge of the metal layer, and the mouth 114 is opposite the mouth 115.

[0119] According to another example, as illustrated in Figures 5 and 7 described later, the first slot 113 has only one curved section, and the mouth 114 is offset from the mouth 115.

[0120] According to another option, illustrated here in figures 5 and 7, the metallic layer 110 has a second slot 117.

[0121] The second slot 117 is for example blind.

[0122] The second slot 117 extends for example into the metallic layer from the opening 112, from a mouth 118, distinct from the mouth 115 of the first slot 113.

[0123] The second slot 117 may include a straight section and / or a curved section.

[0124] In the examples shown, the second slot 117 has only a straight section.

[0125] As further illustrated in [Fig.2], the body 10 includes a first antenna 121.

[0126] The first antenna 121 is here an RFID antenna, for example high frequency (HF).

[0127] The first antenna 121 is arranged in a physical layer distinct from the metallic layer, here on a surface of the first antenna layer 120.

[0128] The first antenna 121 is for example formed of a metal wire.

[0129] The first antenna 121 is arranged so as to comprise at least two sets of turns: - A first set of turns 122 is arranged along the peripheral edge 111 of the metallic layer 110; this set includes at least one turn 123, then it evolves, in a spiral, towards a center of the metallic layer; - A second set 124 of turns is arranged around a perimeter of the opening 112 formed in the metallic layer, so as to encircle the opening 112 with at least one turn 125.

[0130] The two sets of turns are continuously connected electrically, for example by a section of antenna wire 126.

[0131] A winding direction of the metal wire forming the first antenna 121, from the outermost turn 123 to the innermost turn 125, is such that the current IA flows in the same direction in both turns, as illustrated for example in [Fig.8].

[0132] The card 1 further includes a microcontroller 11, also referred to as chip 11, that is to say a secure electronic element.

[0133] The chip 11 is configured to communicate with an external reader, by means of the first antenna 121.

[0134] The first antenna 121 is therefore, for example, tuned to the appropriate frequency with respect to the input impedance of the chip 11 to meet the requirements of the planned communication standards, for example such as ISO 10373, ISO 14443, ISO 18745, EMVCo, or ISO 15693.

[0135] The first antenna 121 is connected to the chip 11 by means of well-known smart card and antenna techniques.

[0136] As illustrated in [Fig.2], one end of the antenna, for example a termination of the larger loop 123, is electrically connected to a first antenna terminal of the chip 11, and a termination of the smaller loop 125, is electrically connected to a second antenna terminal of the chip 11.

[0137] The chip 11 can for example be mounted on a surface of the first antenna layer 120.

[0138] As further illustrated in [Fig.3], the body 10 includes a second antenna 131.

[0139] The second antenna 131 is here an RFID antenna, for example high frequency (HF).

[0140] The second antenna 131 is arranged in a physical layer distinct from the metallic layer, here on a surface of the second antenna layer 130.

[0141] The second antenna 131 is for example formed of a metal wire.

[0142] The second antenna 131 is arranged to include at least two sets of turns: - A first set of turns 132 is arranged along the peripheral edge 111 of the metallic layer 110; this set includes at least one turn 133, then it evolves, in a spiral, towards a center of the metallic layer; - A second set 134 of turns is arranged around a perimeter of the opening 112 formed in the metallic layer, so as to encircle the opening 112 with at least one turn 135.

[0143] The two sets of turns are continuously connected electrically, for example by a section of antenna wire 136.

[0144] A winding direction of the metal wire forming the second antenna 131, from the outermost loop 133 to the innermost loop 125, is such that the current flows in the same direction in both loops.

[0145] Card 1 further includes a passive electronic component 12.

[0146] The passive electronic component 12 includes, for example, an LED or an OLED, possibly connected to a diode bridge, a ceramic piezoelectric component, a screen, or a sensor.

[0147] The second antenna 131 is connected to the passive electronic component 12 by means of techniques analogous to those used to connect the chip 11 to the first antenna 121.

[0148] As illustrated in [Fig.3], one end of the second antenna 131, for example a termination of the larger loop 133, is electrically connected to a first terminal of the passive electronic component 12, and a termination of the smaller loop 135 is electrically connected to a second terminal of the passive electronic component 12.

[0149] The passive electronic component 12 can for example be mounted on a surface of the second antenna layer 130.

[0150] For example, the passive electronic component 12 can be seen from outside the card 1. To do this, the upper coating layer 161 or lower coating layer 162 which covers the passive electronic component 12 can have an opening, and / or at least one transparent area.

[0151] Figures 4 to 7 illustrate examples of the arrangement of the metallic layer 11, the first antenna layer 120, and the second antenna layer 130.

[0152] In figures 4 and 5, the second antenna layer 130 is arranged between the first antenna layer 120 and the metallic layer 110.

[0153] The metallic layer 110 can then be below the two antenna layers, as schematically shown [Fig.4], or above, as schematically shown [Fig.5].

[0154] In the example of [Fig.4], the first antenna layer 120 is then considered above the second antenna layer 130 and the metallic layer 110, while in the example of [Fig.5], the first antenna layer 120 is then considered below the second antenna layer 120 and the metallic layer 110.

[0155] In figures 6 and 7, the metallic layer 110 is arranged between the first antenna layer 120 and the second antenna layer.

[0156] The first antenna layer 120 can then be above the metallic layer, as schematically shown [Fig.6], which corresponds to a stacking as illustrated [Fig.1], or below, as schematically shown [Fig.7].

[0157] In the example of [Fig.6], the second antenna layer 130 is then considered below the metal layer 110, while in the example of [Fig.7], the second antenna layer 130 is then considered above the metal layer 110.

[0158] Thus, the HF RFID antenna and the antenna connected to a passive electronic component can be on the same side of the metal layer, or on each side of the metal layer.

[0159] However, arranging the first antenna layer and the second antenna layer on either side of the metal layer 110 provides better mechanical symmetry for the card; the antennas are then arranged on each side of the metal layer.

[0160] Card 1 can be a purely contactless HF RFID card, or a dual card.

[0161] For example, Figures 4 and 6 illustrate examples of purely contactless card implementation.

[0162] In these embodiment examples of figures 4 and 6, the chip 11 and the passive electronic component 12 are arranged superimposed on each other, and opposite the opening 112 of the metal layer 110.

[0163] In contrast, Figures 5 and 7 illustrate examples of dual card embodiments.

[0164] In these embodiment examples, the chip 11 is opposite the opening 112 of the metal layer 110, while the passive electronic component 12 is laterally offset from the opening 112 of the metal layer 110 and is thus opposite a solid, metal surface portion of the metal layer 110.

[0165] In operation, when the card is placed in the electromagnetic field of an interrogating HF RFID reader (operating, for example, in the RFID frequency band of approximately 13.56 MHz), eddy currents are generated on the metallic layer as a reaction effect opposing the applied magnetic field. The eddy currents flow in turns, which form closed loops, and the outermost (largest) turn 123, corresponding to the longest path of the eddy currents, is the most dominant turn in terms of energy carried. The representation of the electric currents in [Fig. 8] assumes an external magnetic field that is normal and out of plane, as illustrated. The second antenna 131 connected to the passive electronic component 12 is routed in the same way as the first HF RFID antenna 121, so that the second antenna 131, in the presence of the metallic layer, behaves the same way as the first HF RFID antenna 121.

[0166] In the present invention, the first HF RFID antenna 121, due to the winding turns of the first set of turns 122 of the antenna facing the outer periphery of the metal layer 110, generates image currents. Considering the diagram in [Fig. 8], the eddy currents are shown by the thicker arrows indicating the outermost current loop IM on the outer peripheral edge of the metal layer 110. The thinner arrows illustrate the image current IA induced in the first antenna 121.

[0167] As illustrated, the induced current will flow from the outermost loop to the innermost loop that encircles the opening 112.

[0168] The second antenna 131 connected to the passive electronic component 12 works in the same way as the first HF RFID antenna 121.

[0169] Routing the first antenna 121 through these two sets of turns, as shown, with the presence of the first slot 113 opening in the aperture 112, produces an induced current (IA) flowing in the turns of the second set of turns 124 and an eddy current around the aperture which are in the same direction, both in phase with the incident magnetic field.

[0170] When the two antennas are routed in the same direction, they are in phase and when the orientation is different, the antennas are in opposite phase.

[0171] The two antennas behave the same way here.

[0172] For the direction of the magnetic field considered in [Fig.8], the current IA flowing in the turns of the first antenna 121 in the two sets of turns 122, 124 flows in a counterclockwise direction and has the same direction of rotation thanks to the condition of having the same winding direction for the two sets of turns 122, 124. The dominant outer loop of eddy current opposes the incident magnetic field, thus flowing in a clockwise direction along the outer peripheral edge 111 of the metal layer 110, but continues however in a counterclockwise direction at the edge of the opening 112, after having traveled along an edge of the first slot 113.The opening is therefore a region where the energy through the AI ​​image electric current, captured from the peripheral eddy currents, the energy of the eddy currents at the edge of the cavity and that of the magnetic flux through the cavity area, all add up in phase allowing maximum energy collection to power the microcontroller chip 11. This area delimited by the opening 112 is therefore free of any electrically conductive or magnetic material, but it can be filled with any dielectric material 116 without magnetic properties.

Claims

1. Demands Metallic smart card (1) configured to operate contactless in the near field, the card comprising: - a map body (10) formed by a stack of layers, the layer stack comprising at least: - a metallic layer (110), the metallic layer being delimited by a peripheral edge (111) defining a perimeter of the card body (10), and the metallic layer having an opening (112) formed at a distance from the peripheral edge; - a first antenna layer disposed on a first side of the metallic layer, distinct from the metallic layer (110), - a second antenna layer, distinct from the first antenna layer and the metallic layer (110), - a chip (11), positioned opposite the opening (112) of the metallic layer, - a first antenna (121) formed on a surface of the first antenna layer (120), the first antenna being electronically connected to the chip (11), the first antenna having at least one first set of turns comprising at least one so-called outer turn running along the periphery of the card body (10), and the first antenna having at least one second set of turns comprising at least one so-called inner turn surrounding the chip, the first set of turns of the first antenna being distinct from the second set of turns of the first antenna, and the first set of turns of the first antenna being electrically connected to the second set of turns of the first antenna by at least one section of antenna wire, - a passive electronic component (12), - a second antenna (131) formed on a surface of the second antenna layer (130), the second antenna being electronically connected to the passive electronic component (12), the second antenna comprising at least a first set of turns including at least one so-called outer turn running along the periphery of the card body (10), the first set of turns of the second antenna being arranged opposite the first set of turns of the first antenna, and the second antenna comprising at least a second set of turns including at least one so-called internal surrounding the chip, the second set of turns of the second antenna being arranged opposite the second set of turns of the first antenna, the first set of turns of the second antenna being distinct from the second set of turns of the second antenna, and the first set of turns of the second antenna being electrically connected to the second set of turns of the second antenna by at least one length of antenna wire.

2. Card (1) according to claim 1, comprising at least one electrically insulating layer (140), the electrically insulating layer (140) being disposed between the metallic layer (110) and at least one of the first antenna layer (120) and the second antenna layer (130).

3. Card (1) according to any one of claims 1 or 2, wherein the metal layer (110) is disposed between the first antenna layer (120) and the second antenna layer (130).

4. Card (1) according to any one of claims 1 or 2, wherein the second antenna layer (130) is disposed between the first antenna layer (120) and the metal layer (110).

5. Card (1) according to any one of claims 1 to 4, wherein the passive electronic component (12) is opposite the chip (H).

6. Card (1) according to any one of claims 1 to 4, wherein the passive electronic component (12) is offset laterally with respect to the opening (112).

7. Card (1) according to any one of claims 1 to 6, comprising a non-magnetic dielectric material (116) filling the opening (112).

8. Card (1) according to any one of claims 1 to 7, wherein the metal layer (110) has at least one first slot (113) extending between the opening (112) and a peripheral edge (111) of the metal layer, an edge of the first slot connecting a periphery of the opening to the peripheral edge (111) of the metal layer.

9. Card (1) according to any one of claims 1 to 8, wherein the metal layer (110) has at least one second slot (117), the second slot being blind extending into the metal layer from the opening of the metal layer.

10. Card (1) according to any one of claims 1 to 9, comprising a module embedded in a cavity of the card body (10), the module comprising the chip (11).

11. Card (1) according to any one of claims 1 to 10, comprising at least one top coating layer (161) and one bottom coating layer (162), the two antenna layers (120, 130) and the metal layer (110) being arranged between the top coating layer (161) and the bottom coating layer (162).

12. Card (1) according to any one of claims 1 to 11, wherein the passive electronic component (12) comprises an LED, an OLED, an LED or OLED connected to a diode bridge, a ceramic piezoelectric component, a display, or a sensor.

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