EP2300964A2

EP2300964A2 - Antenna for rfid transponder on metal support

Info

Publication number: EP2300964A2
Application number: EP09750192A
Authority: EP
Inventors: Mondher Hakim
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-19
Filing date: 2009-03-04
Publication date: 2011-03-30
Also published as: WO2009141735A3; WO2009141735A4; WO2009141735A2

Abstract

The invention pertains to an antenna for high-frequency RFID transponder and to its method of manufacture. The antenna according to the invention is characterized in that it comprises one or more assemblies each consisting of at least one plurality of turns (7), forming a circuit, associated with an insulating support (8) so that this antenna turns out to be permeable to the magnetic induction flux originating from a reader. The transponder fitted with this antenna when it is placed, stuck or fixed onto a metal support (14) or inserted into the latter allows reading and writing regardless of its orientation with respect to the direction of the magnetic field and offers the same performance in terms of reading and writing distance, with respect to a reader, as that offered by a conventional transponder fixed on a support other than metal.

Description

ANTENNA FOR RFID TRANSPONDER ON METAL SUPPORT

The present invention relates, in general, to an antenna for a radio frequency identification ("RFID") transponder and to a method for making it.

In particular, the invention relates to an antenna for a transponder adapted to be secured to a support of any metal, this transponder in particular of the 13.56 MHz high-frequency type, comprising an RFID integrated circuit or radio-identification chip, in particular a high frequency circuit 13,56 Mhz.

The implementation of RFID technology (Radio, Frequency, Identification) essentially requires two main components namely a reader or base station and a transponder. This pair, which is illustrated schematically in Figure 1 by the reader 1 and the transponder 4 being at a distance d from the metal support 3 or the transponder 5 stuck on the metal support 3, allows the transfer of energy and the operation of the communications between these two components.

For the transponder to work, it must be powered. This power supply, which is generally performed by remote power supply or energy transfer, is valid for both passive transponders and active transponders.

In the current state of the art, the energy transfer is performed using an alternating magnetic field is H (t) listed in the Figurel 2. This magnetic field is produced by the circulation of an alternating current I (t) in the antenna of the reader according to the general formula H = N * I where N is the number of turns of the antenna of the reader. To this magnetic field corresponds, in the medium in which it develops, an associated induction B (t), of the general form B (t) = μ * H (t) where μ represents the magnetic permeability of the medium traversed (air, water, metal, ... etc.).

This induction B (t) causes the appearance of a magnetic flux 0 at a distance X in a conductor of total section S = N * S (N being the number of turns of the antenna of the transponder). This flow is equivalent to: 0 = B (x) * S.

The instantaneous variation of this magnetic flux further produces the appearance of a potential difference u (t) induced at the terminals of the conducting element serving as receiving antenna in the transponder 4 or 5 in FIG. relationship u = d0 / dt.

The quality and quantity of energy transfer thus produced depend on the frequencies on which the antenna circuit of the reader 1 and that of the transponder 4 or 5 are tuned. These frequencies are in general 125 Khz for the low frequencies; 13.56Mhz for high frequencies and 800-900Mhz for very high frequencies.

Therefore, in RFID technology, the following two conditions must generally be fulfilled for the communication between reader 1 and transponder 4 or 5 to be established:

The induction field B (t) created by the reader must cross the antenna section of the transponder 4 or 5 to allow the creation of an induced current in this antenna and ensure, therefore, the transponder power supply. Reader 1 and transponder 4 or 5 must be well tuned to the operating frequency.

Currently, the above-mentioned high-frequency RFID technology at 13.56Mhz described above is used in different environments except the metal which has particular characteristics essentially as follows:

Field 2 of magnetic induction can not pass through the metal. Therefore, the transponder 5 secured directly to the metal support leads to obtaining a zero flux because the induction field B (t) can not cross the antenna section of the transponder which, consequently, does not can be powered by remote power supply.

The magnetic permeability of the metal is very low. Therefore, the reader 1 located far from the metal support on the one hand and the transponder 5 secured directly to the metal support on the other hand, are not tuned to the operating frequency.

In order to reduce the disturbance of the magnetic field thus produced, several solutions have been proposed to adapt the use of RFID technology including high frequency in metal environment. For this purpose, it is provided in the patent application WO 2006/105007 the use of specific materials placed between the transponder antenna and the metal support so as to optimize the reading distances that is to say the distances separating the transponder from the reader. For this purpose, ferromagnetic materials such as nickel / zinc / ferrite or manganese / zinc / ferrite have been suggested. On the other hand, it has been reported in WO 2006/124270, the use of multilayer films of a substrate dispersed in a binder and located between the antenna and the metal support. These multilayer films comprise about two to one hundred pairs of layers each alternately of a crystalline ferromagnetic metal layer adjacent to a dielectric layer.

Other solutions have also been proposed which implement: a) an insulator comprising a complex magnetic permeability material interposed between the RFID tag and the metal substrate, as described in WO 2006/044168, or b) an antenna comprising a conductive element and, interposed between it and a metal support, a soft magnetic element, for example a composite material formed of an organic material and ferrite grain powder, an amorphous film or the like, as reported in WO2003 / 061069. Despite all these attempts, current inventions have not been able to provide 100% reliable results since there is still no way to read the transponder and to write at distances from the reader equivalent to the distances generally obtained in a system using a transponder placed in an environment other than metal.

Moreover, the patent application EP1484816 describes an RFID transponder provided with an antenna in the form of a conductive wire wound on a soft magnetic support disposed substantially parallel to a metal surface in contact with this transponder. However, such an embodiment has a real disadvantage because of the fragility of this element soft magnetic, which can become brittle in time, and because of its relatively prohibitive cost.

As a result, the use of high-frequency RFID technology 13.56Mhz could not be controlled, to date, when it comes to placing the transponder antenna 5 directly on the metal support 3 or avoiding the use of specific ferromagnetic or other materials.

The present invention aims to provide an antenna for a transponder, especially high frequency 13.56 MHz, which can be secured directly to any type of metal support (iron, steel, stainless steel, copper, etc.), for example by simple juxtaposition, by fixing by any means such as by gluing or even by insertion inside this metal support for example by juxtaposition or fixing in a groove or indentation made in this metal support avoiding the use of one or more additive materials located between the metal support and the transponder in particular to reduce the size and cost. To achieve this goal, the antenna of the kind indicated above is characterized in that it comprises one or more assemblies each consisting of at least a plurality of turns, forming a circuit, associated with an insulating support so that this antenna s' is permeable to the magnetic induction flux from a reader.

By "turns associated with an insulating support" is generally meant turns in direct contact and in various ways with the insulating support. It may be, for example, turns disposed entirely on and around the support, that is to say wound on it, or disposed entirely within this support or alternatively, and preferably, arranged partially on the support and partially inside thereof.

When the antenna comprises several sets each consisting of a plurality of turns associated with an insulating support, each group of this type will be referred to hereinafter as the "antenna element".

In particular, the antenna according to the invention may comprise an assembly consisting of at least a plurality of turns disposed entirely on and around an insulating support, that is to say wound on it, or disposed entirely within this insulating support.

However, according to another particular and preferred embodiment, the antenna comprises one or more assemblies each consisting of a plurality of turns forming a circuit, partially arranged on the insulating support and partially inside thereof, these sets possibly being joined together.

The transponder comprising an antenna according to the invention offers the maximum reading and writing when the direction of the magnetic field is perpendicular to the section of the turns of the antenna.

Accordingly, according to another characteristic of the invention, the antenna comprises one or more pluralities of turns of non-parallel section to the surface of the metal support, preferably of section perpendicular to the surface of this metal support.

In addition, according to a further feature of the invention, the insulating support is substantially parallel to the metal support surface.

This insulating support may be configured in the form of, for example, a cylinder or a polyhedron, preferably a rectangular parallelepiped. When this polyhedron is a rectangle parallelepiped, the turns may be arranged in full on the opposite faces to each other or in all within this parallelepiped to form in these two cases a continuous circuit.

However, the turns preferably extend partially on and partially inside polyhedron faces. When this polyhedron is a rectangular parallelepiped, the turns in question usually extend over two opposite faces and along the other two opposite faces, however, inside this parallelepiped so as to form a continuous circuit.

According to a first embodiment of the invention, the antenna comprises a single assembly consisting of a plurality of turns associated with an insulating support, that is to say a single antenna element.

In such a case, the reading and writing distance is a function of the angle between the direction of the magnetic field and the section of the turns. Thus, when the direction of the magnetic field is perpendicular to the section of the turns, the reading and writing distance is maximum. However, when the direction of this magnetic field is parallel to the section of these turns, reading and writing are no longer possible.

The transponder provided with an antenna comprising a single antenna element is sufficient for a large number of applications that do not impose different orientations of this transponder with respect to the direction of the magnetic field.

Some applications, however, require the intervention of a transponder capable of offering the maximum of reading and writing, whatever the angles of orientation. In these cases, the transponder is provided with an antenna comprising two antenna elements or more, these antenna elements being superimposed and having angles of different orientations so as to provide a maximum distance and constant reading and writing irrespective of the orientation of the transponder with respect to the direction of the magnetic field. Accordingly, according to another embodiment of the invention, the antenna comprises several sets each consisting of a plurality of turns associated with an insulating support, the plurality of turns forming between them different angles. In such an embodiment, the turns of each of the assemblies can be interconnected in series or in parallel, in which case the inputs of the turns are interconnected and the outputs of these turns are also connected to each other. According to a first particular implementation of this embodiment of the invention, the antenna comprises two sets each consisting of a plurality of turns associated with an insulating support, the two pluralities of turns forming between them angles of 90 ° . In this case also, the reading and writing distance is a function of the angle between the direction of the magnetic field and the section of the turns of each of the two sets. Thus, when the direction of the magnetic field is perpendicular to the section of the turns, the reading and writing distance is maximum. In addition, regardless of the direction of the magnetic field, reading and writing are possible in this case also given the arrangement of the two pluralities of turns forming between them angles of 90 °. In addition, according to a second implementation of this embodiment of the invention, the antenna comprises three sets each consisting of a plurality of turns associated with an insulating support, the three pluralities of turns forming between them angles of 120 °.

In this case, the reading and writing distance is maximum and constant regardless of the angle between the direction of the magnetic field and the section of the turns of each of the three sets. In addition, whatever the direction of the magnetic field, reading and writing are also possible given the arrangement of the three pluralities of turns forming between them angles of 120 °. The antenna according to the invention can be manufactured according to various methods which essentially depend on its configuration.

Thus, when the turns are arranged entirely around the insulating support or inside thereof, the antenna can be manufactured by making turns by winding an electrically conductive wire respectively on the different outer faces of the support insulation or on an insulating sleeve which is completely covered by an insulating material. However, when it consists of at least one set each comprising a plurality of turns partially disposed on the insulating support and partially integrated inside thereof, the antenna can be made from a printed circuit board multilayer.

In this embodiment, each set consisting of a plurality of turns associated with an insulating support is manufactured on two layers separated from each other by an insulating material, the turns of each set having different orientation angles. allowing reading and writing from a reader regardless of the orientation of the transponder provided with these antenna assemblies with respect to the direction of the magnetic field.

Also, according to another preferred feature of the invention, the antenna when it consists of at least a plurality of turns each arranged partially on an insulating support and partially inside thereof is manufactured by implementation. process according to a method characterized in that on two opposite faces of the insulating support configured in a parallelepiped, for example a rectangular parallelepiped, tracks are printed in an electrically conductive metal which is connected to holes drilled from one side to the other in this case. an insulating support from one of said faces to the other, these holes being covered with an electrically conductive metal, so that the assembly consisting of the printed tracks and the holes forms a continuous spiral circuit.

According to another characteristic of the invention, the assembly thus manufactured is secured, for example by gluing, to one or two other analogous assemblies and this, via the two faces carrying printed tracks in such a way that the pluralities of turns form between them different angles.

Thus, when the antenna is formed of at least two analogous assemblies manufactured and joined as before, the turns will appear on the two opposite outer faces of the single insulating support formed by the combination of the different insulating supports of the starting assemblies. The remainder of this single circuit formed of tracks and connection holes will be located within this single insulating support. For an appropriate implementation of the latter method, it is advantageous to start with a printed circuit in its initial state and transform it by the conventional technique of manufacturing Multilayer printed circuits to obtain an antenna which constitutes the essential element of a transponder.

This technique makes it possible to obtain a printed circuit with a set of track traces on two opposite faces of the insulating material essentially on the support face on the side of the transponder components and on the support side on the side of the welds. These tracks are, in general, made of electrical conductors, preferably copper wires of about 35 microns thick covered with a protective layer of tin as well as the connection holes between the tracks. Tin is also used as a welding material for transponder components. As for the insulating material, it is usually a glass fiber reinforced epoxy material, for example the FR4 material. The conductive tracks connected to the conductive holes formed in the insulating support and form turns which ultimately constitute the above-mentioned transponder antenna.

In a second step, the manufactured antenna is connected to the RFID circuit by the commonly known wiring technique (mounting and welding) so as to constitute the final transponder. This may be used on or in a metal support without the addition of any ferro-magnetic material or any other material and without the need to move the transponder away from the metal support.

In some cases, however, the transponder may not be tuned to the desired frequency, for example 13.56 Mhz. It is then planned to add an additional capacity called "tuning capacity" in order to obtain an antenna granted with the RFID circuit and, ultimately, a transponder that meets the needs. This operation of adding a capacity tuning is performed according to a well-defined calculation mode which is a function of the value of the inductance of the antenna and the internal capacitance of the RFID circuit.

The invention will be better understood and other objects, features and advantages thereof will appear more clearly in the following description with reference to the accompanying schematic drawings given solely by way of non-limiting examples illustrating different modes of embodiment of the invention and in which: - Figure 1 is a schematic representation of a transponder of the state of the art in a magnetic field, Figure 2 is a perspective representation of an antenna at a plurality of turns according to the invention, mounted in a transponder arranged on a metal support, FIG. 3 is a perspective representation of the antenna in FIG. 2 mounted in a transponder arranged in a metal support, FIG. plan of a transponder provided with another embodiment of an antenna with an element according to the invention, FIG. 5 is a representation in perspective ive of a transponder provided with the antenna in FIG. 4 and arranged on a metal support or the like, FIG. 6 is a perspective representation of an antenna with two pluralities of turns, according to the invention, mounted in a transponder arranged on a metal support, - Figure 7 is a perspective representation of an antenna with two pluralities of turns, according to the invention, mounted in a transponder arranged in a metal support, FIG. 8a is a plan view of a transponder provided with a first antenna element according to the invention, FIG. 8b is a plan representation of the transponder in FIG. 8a provided with a second antenna element. according to the invention, FIG. 9 is a perspective representation of an antenna with three pluralities of turns, according to the invention, mounted in a transponder arranged on a metal support, - FIG. 10 is a perspective representation of a antenna having three pluralities of turns, according to the invention, mounted in a transponder arranged in a metal support, FIG. 11a is a plan representation of a transponder provided with a first antenna element according to the invention, the FIG. 11b is a plan view of the transponder in FIG. 11a provided with a second antenna element according to the invention; FIG. 11c is a plan representation of the transponder in FIGS. 11a and 11b provided with a third element; antenna antenna according to the invention.

EXAMPLES 1 and 2

ANTENNAS HAS AN ELEMENT

As represented in FIGS. 2 and 3 and according to a first embodiment of the invention (EXAMPLE 1), a transponder disposed respectively on a metal support 6 or inside a groove made in it, comprises a antenna composed of a spiral circuit 7 wound around an insulating support 8 and that a chip RFID high frequency 13,56Mhz and a capacity of tuning 10.

However, according to another embodiment (EXAMPLE 2), visible in FIGS. 4 and 5, the antenna comprises, integrated partially inside an insulating support 8, a spiral circuit 7 comprising tracks 11 (component side ) and 12 (welded side) located respectively on two opposite faces of the insulating support 8 configured in rectangular parallelepiped. These tracks are electrically connected to holes 13 pierced right through in this insulator 8 and this spiral circuit is further connected to an electronic chip 9 RFID itself connected to a tuning capacity 10.

FIG. 5 also shows the turns of the spiral circuit 7 perpendicular to the metal support 14. Similarly, it can be seen that the direction of the magnetic flux is perpendicular to the section of the turns since this flow is parallel to the axis 16 of the antenna, which axis is perpendicular to the section of these turns.

This antenna can be manufactured by producing a double-sided printed circuit with metallized holes. To this end, we start from an insulating support 8 in the form of a plate with a thickness of 0.5 to 3.2 mm FR4 epoxy glass covered on two opposite sides of a very thin copper layer of a thickness of 18 to 75 microns.

By means of a digitally controlled device, holes 13 are firstly drilled from one end of this covered plate to make the future electrical connection between the tracks and the layers. This operation is performed on the basis of a computer file previously designed by CAD software (computer-aided design) and in accordance with positions determined for the passage holes 13 or vias and for the connection of the components.

Subsequently, a first "flash" metallization is carried out by deposition of a layer of copper on the lateral surface of the holes 13 to render the two opposite faces covered with copper conductive. This metallization is performed first by a chemical process to form a deposition of an electrostatic layer of palladium then by an electrolytic process to form a copper deposit. A lamination is then carried out which fixes, on the surface of the copper layer deposited on the two opposite faces, a film of resin (RISTON) sensitive to ultraviolet rays. This operation is performed in a room lit by a yellow light. After printing the tracks and pads of the transponder components on a transparent support film from the CAD software, this transparent film is applied to the surface of the photosensitive layer and exposed to ultraviolet light by means of platesetter. The photosensitive layer, located below the tracks and pellets, is thus protected against UV contrary to the layer located below the transparent part of the film which will be attacked by these same UV. During the next development step, the photosensitive layer is etched by an alkaline chemical which dissolves the UV-protected photosensitive layer so as to provide a board whose tracks and pellets are made of bare copper while the remains is covered by the photosensitive layer.

By an electrolytic method, a second metallization called "reinforcement" is then carried out by producing a depositing copper on the bare copper part represented by the tracks, the pellets and the inside of the holes, then applying a deposit of tin, also by an electrolytic process, on the bare copper part represented by these same tracks, pellets and holes . A stripping operation is then carried out by means of a chemical product based on caustic soda which has the effect of dissolving the sensitive layer, which provides a card whose tracks 11 on one of the faces and the tracks 12 on the other side as well as the pellets and the inside of the holes are covered with a layer of tin while the rest of the copper is bare.

In order to carry out an etching, the copper is then dissolved by spraying an ammonia-based product while the tin remains, which provides a card whose tracks, the pellets and the inside of the holes are made of copper. covered with a layer of tin while the rest of the card is made of FR4 insulation.

By the screen printing technique, a layer of varnish is then deposited on the entire surface of the card, with the exception of the pellets so as to be able to weld the components, this varnish serving as protection against, for example, oxidation, humidity, etc.

EXAMPLES 3 and 4

TWO-ELEMENT ANTENNAS

As shown in FIGS. 6 and 7 and according to another embodiment of the invention (EXAMPLE 3), a transponder disposed respectively on a metal support 6 or inside a groove made in it, comprises a antenna composed of a first spiral circuit 7 wound around an insulating support 8, a second spiral circuit 17 wound around the same support 8 as well as a high frequency 13.56 Mhz RFID chip 9 and a tuning capacitor 10. The two circuits in FIG. spiral are interconnected and form angles of 90 ° between them.

However, according to another embodiment (EXAMPLE 4), visible in FIGS. 8a and 8b, the transponder shown is provided with a 13.56 Mhz RFID chip 9, a tuning capacitor 10 and an antenna which comprises: a) a first antenna element represented in FIG. 8a, that is to say, partially integrated inside an insulating support 8, a spiral circuit comprising tracks 11 and 12 located respectively on two opposite sides of the insulating support 8 configured in a rectangular parallelepiped, these tracks being electrically connected to holes 13 pierced right through in this insulator 8 and b) a second antenna element similar to the first but whose spiral circuit forms 90 ° angles with the spiral circuit of the first antenna element, this second antenna element being shown in FIG. 8b, where the tracks 18 and 19 located respectively on two opposite faces of the insulating support 20 are distinguished. than the holes 21 of electrical connection.

By carrying out the process described in Example 2, a 4-layer printed circuit consisting of two double-sided circuits with metallized holes is produced, which corresponds to a first and a second set of turns associated with their respective insulating support. , i.e., a first and a second antenna element.

These two double-sided circuits are then connected together in parallel or, preferably, in series then superimposed so that they form angles of 90 ° between them. The two insulating supports are then glued by pressure.

EXAMPLES 5 and 6

ANTENNAS WITH THREE ELEMENTS

As represented in FIGS. 9 and 10 and according to another embodiment of the invention (EXAMPLE 5), a transponder disposed respectively on a metal support 6 or inside a groove made in it, comprises a antenna consisting of a first spiral circuit 7 wound around an insulating support 8, a second spiral circuit 17 and a third spiral circuit 22 wound around the same support 8 and a high frequency RFID electronic chip 9 13.56 Mhz and a tuning capacity 10. These three circuits are interconnected and form angles of 120 ° between them. However, according to another embodiment (EXAMPLE 6), visible in FIGS. 11a, 11b and 11c, the transponder shown is provided with a 13.56 Mhz RFID chip 9, a tuning capacitor 10 and a receiver. antenna which comprises: a first antenna element represented in FIG. 11a, that is to say, integrated partially inside an insulating support 8, a spiral circuit comprising tracks 11 and 12 located respectively on two opposite faces of the insulating support 8 configured as a rectangular parallelepiped, these tracks being electrically connected to holes 13 pierced right through in this insulator 8, b) a second antenna element similar to the first but whose spiral circuit forms an angle of 120 ° with the spiral circuit of the first antenna element, this second antenna element being shown in FIG. 'tracks 18 and 19 are respectively located on two opposite sides of the insulating support

20 as well as the holes 21 of electrical connection, c) a third antenna element similar to the first two but whose spiral circuit forms an angle of 120 ° with the spiral circuits of the first and second antenna elements, this third antenna element being shown in Figure lie where we distinguish the tracks 23 and 24 located respectively on two opposite faces of the insulating support 25 and the holes 26 of electrical connection. By carrying out the process described in Example 2, a 6-layer printed circuit consisting of three double-sided circuits with metallized holes is produced, which corresponds to a first, a second and a third set of turns associated with one of them. respective insulating support, that is to say a first, a second and a third antenna element.

These three double-sided circuits are then interconnected in parallel or, preferably, in series so that they form between them angles of 120 °. The three insulating supports are then glued by pressure.

The transponder provided with an antenna according to the invention whether it is only placed on a metal support or on the contrary fixed directly thereto or inserted into it, can be in any size. In all cases, a reading and writing can be performed at a distance from the reader that will vary according to different parameters namely the dimensions of the antenna, the thickness of this antenna and the number of its turns.

Thus, when placed on a metal support, such an X-size transponder offers the same performance in terms of read and write distance as those provided by a standard, standard transponder on the market, this transponder being also of the same size X but placed on a non-metallic support.

Furthermore, the transponder provided with an antenna according to the invention may be placed inside a groove or notch made in a metal support and then covered, if necessary, with a layer of insulating material, for example a resin . Advantageously, this layer of insulating material will be flush with the surface of the metal support so as to completely hide the presence of this transponder.

Such a transponder, equipped with an antenna according to the invention, will provide traceability operations, security, control or statistics in many fields of application, for example in the field of gas cylinders.

Claims

claims

Antenna for an RFID transponder adapted to be secured to a support (6, 14) of any metal, this transponder comprising an integrated circuit (9) RFID, characterized in that it comprises one or more sets each consisting of at least a plurality of turns (7), forming a circuit, associated with an insulating support (8) so that this antenna is permeable to the magnetic induction flux coming from a reader (1).

2. Antenna according to claim 1, characterized in that it comprises an assembly consisting of at least a plurality of turns disposed wholly on and around the insulating support or disposed entirely within it.

3. Antenna according to claim 1, characterized in that it comprises one or more sets each consisting of a plurality of circuit turns disposed partially on the insulating support and partially inside thereof, these sets being optionally secured between them.

4. Antenna according to one of claims 1 to 3, characterized in that it comprises one or more pluralities of turns of non-parallel section to the surface of the metal support.

5. Antenna according to claim 4, characterized in that the turns are of section substantially perpendicular to the surface of the metal support.

6. Antenna according to one of claims 1 to 5, characterized in that the insulating support is substantially parallel to the surface of the metal support,

7. Antenna according to one of claims 1 to 6, characterized in that it comprises a single assembly consisting of a plurality of turns associated with an insulating support.

8. Antenna according to one of claims 1 to 7, characterized in that it comprises several sets each consisting of a plurality of turns associated with an insulating support, the plurality of turns forming between them different angles.

9. Antenna according to claim 8, characterized in that it comprises two sets each consisting of a plurality of turns associated with an insulating support, the two pluralities of turns forming between them angles of 90 °.

10. Antenna according to claim 8, characterized in that it comprises three sets each consisting of a plurality of turns associated with an insulating support, the three pluralities of turns forming between them angles of 120 °.

11. Antenna according to one of claims 1 to 10, characterized in that it is associated with a capacity

(10) forming tuning ability.

12. Antenna according to one of claims 1 to 11, characterized in that the RFID integrated circuit is a 13.56 MHz high frequency circuit.

13. Antenna according to one of claims 1 to 12, characterized in that it allows the transponder reading and writing from the reader (1) regardless of its orientation with respect to the direction of the magnetic field.

14. Antenna according to one of claims 1 to 13, characterized in that it allows the transponder a reading and writing distance similar to the corresponding distance offered by a standard transponder placed in a non-metallic environment.

15. Antenna according to one of claims 1 to 14, characterized in that it offers the transponder, placed at any point of the metal support, fixed by any means to it or inserted into it, a possibility reading and / or writing from the reader (1) when said metal support is moving and / or rotating.

16. Antenna according to claim 15, characterized in that the transponder is inserted into a groove or notch made in the metal support and optionally covered by a layer of insulating material which is flush with the surface of the metal support.

17. Antenna according to one of claims 1 to 16, characterized in that it allows the transponder to perform traceability operations, security, control, statistics.

18. Antenna according to one of claims 1 to 17, characterized in that it allows the transponder use in relation to gas cylinders.

19. A method of manufacturing an antenna consisting of at least one set each comprising a plurality of turns partially arranged on the insulating support and partially integrated inside thereof according to one of claims 1 to 18, characterized in that this antenna is manufactured from a multilayer printed circuit.

20. The method of claim 19, characterized in that each set consisting of a plurality of turns associated with an insulating support is manufactured on two layers separated from each other by an insulating material, the turns of each set having different orientation angles allowing reading and writing from a reader (1 ) regardless of the orientation of the transponder, provided with these antenna assemblies, with respect to the direction of the magnetic field, these sets being subsequently secured by gluing.

21. The method of claim 19 or 20, characterized in that on two opposite faces of an insulating support configured in parallelepiped is printed tracks in an electrically conductive metal which is connected to holes drilled from one side to the other this insulating support from one of said faces to the other, these holes being covered with an electrically conductive metal, so that the assembly constituted by the printed tracks and the holes forms a continuous spiral circuit.

22. The method of claim 21, characterized in that the assembly is secured by gluing to one or two other similar sets and this, through the two carrying faces of the printed tracks.