WO2013041783A1

WO2013041783A1 - Uhf electronic radio frequency identification in a metallic environment with a middle layer with impedance matching meanders

Info

Publication number: WO2013041783A1
Application number: PCT/FR2012/000371
Authority: WO
Inventors: Philippe Pannier; Arlacon JUVENAL; Mathieu EGELS
Original assignee: Universite D'aix Marseille; Centre National De La Recherche Scientifique
Priority date: 2011-09-21
Filing date: 2012-09-17
Publication date: 2013-03-28
Also published as: FR2980291B1; FR2980291A1

Abstract

The invention concerns electronic radio frequency identification in the ultra-high frequency (UHF) range, to mark a product (2) for identification in a metallic environment. For this purpose, an electronic device (1) comprises at least one arrangement for adjusting impedance (15) in the shape of a meander with conductor length (L) compensation. This meandering conductor arrangement (15) is connected to a first antenna (8) dipole (16) on an emission face (10) and to a conductive layer (12) of an earth face (7), while an electronic component (3) is connected to the first antenna dipole (16) by an internal interface conductor (9) in the form of a plated through hole (11) and to a second antenna dipole (18) by another internal interface conductor (9) in the form of a plated through hole (11), passing through the thickness of an upper level (4) of substrate.

Description

«UHF radio frequency electronic identification in metallic environment with meandering mid-layer adaptation

impedance "

The invention relates to the electronic identification by radio frequency, called RFI D medium or environment called "metallic".

For decades, traceability data has been introduced into an electronic component, for example in an electronic device with memory or a processor or "transponder". This device is itself physically attached to a product to which the coupled traceability data correspond. We are talking about RFI identification mark D.

Here, the electronic device provided with the component is called "electronic device", whether it is an electronic tag (English "Tag") or another type of transponder. One of the practical aspects of RFID identification D is remote reading / writing of traceability data (or marking information) between a remote reader and the electronic device. We speak of contactless reading / writing.

Currently, standards standardize RFID interfaces in the field of marking, depending on the radio frequency range used, such that the ISO 18000-6 standard defines UHF communication parameters for an interface between 860 MHz and 960 MHz.

The radiofrequency regulations on this standard are, for the European geographical area, established according to: ETSI EN 302 208-1 V1 .3.1. The predefined maximum transmit power is 2 Watt ERP. For the USA, this is the standard "Federal Communications Commission, Title 47, Telecommunications, Chapter 1, Part 15-4-05-05" which applies, with a frequency of 902MHz to 928MHz, and according to the "Section 15.247 "a predefined maximum transmit power of 4 Watt EIRP.

As for the industrial applications of radio frequency identification RFID, they are common and varied, from logistics to anti-theft marking, through the operational monitoring of products or their constituents. As far as the invention is concerned, the industrial fields of application concerned are aimed at all industries wishing to improve the logistic management of "metallic" products or those operating in a highly "metallic" environment.

By products or "metallic" environment is meant any products provided with an RFID marking and having and / or neighboring electrically conductive structures, structures capable of interfering in a read / write without radio frequency contact.

In particular, the invention is aimed at the automotive industry, aeronautics, mass retailing especially on metallized packaging products, and industries marketing various metal products.

At present, the RFID identification is faced with various technical problems, when the contactless reading / writing must take place in a "metallic" environment. To better define a "metallic" environment, one can refer to: http://en.wikipedia.org/wiki/Radio-identification. It is stated in this document that contactless reading / writing for products "located in a metal container is more difficult". "The possible communication distance is decreased by the effect of Faraday cage, which carries out electromagnetic shielding. Thus, a metallic environment is such that it forms an undesirable electromagnetic shielding because of which the contactless read / write is compromised (reading distance close to the contact), or even rendered impossible.

It is conventional to seek to improve contactless read / write when the RFID electronic device is on a product in a metallic environment.

But there is currently no practical technical approach in some cases where both the labeled product forms a strong electromagnetic shielding, especially when the industrial application is subject to other limiting factors, environmental or clean .

Thus, it is not uncommon for other environmental factors to participate in electromagnetic shielding. These factors include, near the contactless read / write spaces: the composite structures (on, in and around the object or component to be marked); the presence of parasitic electromagnetic fields, for example due to the operation of computers, radars and other electronic devices.

The high resistance to tearing and / or extreme environmental temperatures or hygrometries are other factors of the same order.

Other technical problems can arise with binding industrial applications.

In particular, the RFI D contactless read / write reliability factors are more important when it conditions the safety or the integrity of a marked product, or even of its occupants if it is a habitable product such as 'a vehicle. Conversely, in some Commonly used logistics applications for consumer products, security is often less important than other read / write criteria, such as speed of access.

Another limiting factor of an RFI D contactless read / write, is the volume and dimensioning of the electronic device affixed to the marked product. Especially since a large RFID contactless read / write distance factor is required. Large dimensions favoring RFI D contactless reading / writing in a metallic context, it is understood that the read / write and dimensional restriction factors are antinomic.

The same is true for mass factors, which can become dominant in certain industrial applications, particularly for human-powered equipment or for air transport, particularly in the field of rotary wing aircraft such as helicopters. .

In addition, so-called extreme external operating environment factors add considerable constraints to RFI-free contact reading / writing. Notably, these extreme environmental factors include high or low temperatures; high hygrometry conditions; and the conditions of high atmospheric pressure.

It is understood that currently when several of these environmental factors are combined, the reliability of contactless read / write as well as its durability are difficult, if not impossible to maintain. This is problematic, especially when the reliability of contactless read / write must be guaranteed, for security reasons in particular.

Finally, it goes without saying that any industrial application is subject to pecuniary factors, which are also antithetical to development of contactless read / write (RFID) hardware and methods at a financially acceptable cost.

In this context, there are documents relating to attempts to obtain contactless reading / writing on a metallic product and / or in a metallic environment.

Document US20030193438 describes a PIFA antenna, the use of a loop line in an intermediate layer. One end of the line is connected to the power supply and the other to the radiating element. The length of the line as well as the use of stub sections in the intermediate layer, for impedance matching. This document could be at this stage considered to be the closest of the invention.

The document US20100073254 describes the use of a structure (elementary cell) of metamaterials (MTM) as a radiating element. An MTM structure has three levels of metallization. A first level includes the MTM element. The second level includes a power supply (CPW) of an antenna and the third level forms a ground plane. The insertion of a meander is done on the first CPW in the MTM element to realize the impedance matching.

Document KR20070105589 describes a component sandwiched between two substrate layers, with a component connection dipoles by internal conductors. An RFI D antenna is provided with an inner slot to reduce the length and is installed with the RFI D chip on a metal plate. The antenna and type PIFA (Planner Inverted F Antenna). The slot is formed at a portion below the RFID chip and has a shape in straight lines confined in a rectangular periphery.

Also, the document (Aceli - 2004) (to be consulted under http: // www. Hyper-rf.com/Hyperfrequences/Antennes / Antennas-VI I Pl FA.html) describes a portable terminal with an antenna curved, flat and short-circuited (in English Planar Inverted-F Antenna or PIFA). An emission face is connected to the electronics of the terminal, and a short-circuiting element is connected to a conductive plane of grounding. Performance can be improved by adding properly placed charges.

For general information, the document "Orthogonally Proximity-Coupled Patch Antenna for a Passive RFID Tag on Metallic Surfaces" (Hae-Won Son and Gil-Young Choi, ETRI, published online at http://interscience.wiley.com under DOM 0.1002 / mop22222 August 8, 2006) describes some principles of tuning a chip with an antenna. An internal grounding pin or "metallized hole" called "via", is disposed inside a substrate, perpendicular to the resonant length. The document "Planar Wire Type Inverted-RFID Tag Antenna

Mountable on Metallic Objects "(Ukkonen, D et al.); published online at http://www.ieee.org under IEEE 0-7803-8302-8 / 04/2004 describes inverted F type antennas called "IFA".

The same is true of the document "Low-Profile Meandered Patch Antennas for RFID Mountable Tags on Metallic Objects" (H. D Chen et al.); published online at http://www.ieee.org in "IEEE Antennas and Wireless Propagation Letters", Volume 9, 2010.

The document "A RFID Miniature Tag Antenna Design for Metallic Objectcs Application" (S.L. Chen); published online at http://www.ieee.org under IEEE 536-1225 / 2009, also describes antennas of the IFA type, but in a vertical loop.

The document "Miniaturized Patch Antenna for Radio Frequency Identification of Metallic Objects" (A. Ghiotto et al.); published online at http://www.ieee.org under IEEE978-1-4244-1780-3 / 08/2008, discloses IFA-type antennas with a U-slot in the so-called "patch" antenna conductor.

The document "Design of a UHF RFID Metal tag for long reading range using a Cavity Structure" (K.H. Lee et al.); published online at http://www.ieee.org under IEEE 978-1-4244-2642-3 / 08/2008, describes cavity-type IFA antennas.

"A Small RFID Tag Antenna to Identify Metallic Objects" (W. Choi et al.); published online at http://www.ieee.org under IEEE 978-1-4244-2042-1 / 08/2008, describes substrates with a high permittivity, in particular in ceramics.

"Ceramic Patch Antenna for UHF RFID Tag Embedded in Metallic Objects" (J. S. KIM et al.); published online at http://www.ieee.org under IEEE 978-1-4244-3647-7 / 09/2009, describes a compact high-permittivity, high manufacturing cost the document above.

The document "Low-Profile RFID Antenna Tag Using AMC Compact for Metallic Objects" (D. KIM et al.); published online at http://www.ieee.org under IEEE 1536-1225-2008, describes the use of artificial magnetic conduction surfaces or AMD, the cost of manufacture is high.

The document "Passive UHF RFID with Ferrite Electromagnetic Band Gap (EBG) Material for Metal Object Tracking" (B. GAO et al.); published online at http://www.ieee.org under IEEE 978-1-4244-2231-9 / 08/2008 describes electromagnetic band gaps in ferrite or EBG.

The "Design of Novel Dipole-Type Tag Antennas using Electromagnetc BanGap (EBG) Surface for Passive RFID Applications" (DU Sim); published online on the site http: // www. ieee. org I I EEE 1 -4244-0878-4 / 07/2007 also describes spaces in electromagnetic band in ferrite or EBG

None of the documents mentioned, provides a compact antenna PI FA with a meander in the intermediate layer and which is not directly part of the radiating element and a power supply of the antenna that is tested for a "metallic" context.

In no case is there a combination where one of the radiating elements of a first layer is connected to a meander end in an intermediate layer and where another end of the meander is connected to a ground plane and not to food. In general with known techniques, the antenna feed is between the two radiating elements of the first layer and not between the ground plane and the meander. In other words, the current offer does not fully satisfy certain technical fields, while industrial applications that are not very common and / or with multiple constraints can not have adequate RFI D read / write means.

Thus, many technical problems remain to be solved today for industries that require their RFI D electronic devices to be designed specifically for their needs, with a small footprint and a range of order of the meter at least. As we have seen, the use of generic RFI D electronic devices can not be effective, safe and reliable in a metallic medium, due to the cancellation of the electric field at the interface of the metal. In particular, the usual electronic RFI devices fail to produce from the radio frequencies received at the antenna, the energy necessary to send the information to a reader. It is in this context that the design of RFID electronic devices for the identification of metal objects is a challenge. It therefore seemed useful to propose RFID electronic devices whose characteristics such as the antenna impedance and the radiation pattern, at the origin of the read distance reductions in the known techniques, are perfectly adapted to a metal environment, while ensuring a small footprint, exceptional strength, and a production cost that does not strike the intended applications. For this purpose, the various objects of the invention are defined by the appended claims, electronic device, marked product and electronic identification system by radio frequency.

According to one embodiment, the invention relates to an electronic device for identification by radio frequency (RFID) in the range of ultra high frequencies (UHF). This device is intended to mark an object to be identified in a metallic environment.

This electronic device comprises at least:

a stack in a direction of thickness of the electronic device of at least one higher level of dielectric substrate and of a lower level of dielectric substrate, with on the one hand an emission face on the upper level and on the other hand from one side of mass ^as' the lower level;

an electronic component having a user memory, having a predetermined impedance and being attached between the lower level and the higher level of dielectric substrate;

a curved, flat and short-circuited antenna (PI FA) extended on said emission face and connected on the one hand to the electronic component, and by at least one short-circuiting element, to a conductive layer of grounding on the other hand. This ground plane being extended on the mass face of the lower level of substrate.

According to one embodiment, the electronic device comprises, in the thickness direction, between an inner lower face of the upper substrate level opposite to the emission face and an inner upper face of the lower substrate level opposite to the mass face, the minus one meander-shaped impedance adjustment arrangement with compensating conductive length; this conductive meander arrangement being, on the one hand, connected by at least one upper interface conductor to a first antenna dipole on the emission face and, on the other hand, connected by at least one lower interface conductor to the mass face; while the electronic component is connected on the one hand to said first antenna dipole by an internal interface conductor in the form of a metallized hole traversing in thickness the upper level of substrate as well as on the other hand to a second antenna dipole by another internal interface conductor in the form of a metallized hole traversing the upper level of the substrate in thickness. According to one embodiment, the electronic device comprises at least one meander arrangement in the form of a conductive layer affixed to one of the inner inner or inner faces of the upper or upper inner level of the lower substrate level, with a substantially parallelepiped contour and at least one dielectric notch emerging transversely and / or longitudinally respectively in a transverse / longitudinal direction perpendicular to the thickness direction of the electronic device.

According to one embodiment, the electronic device comprising between the emission face and the mass face, a peripheral thickness wafer, at least one meander arrangement is contiguous to the peripheral thickness wafer. According to one embodiment, the electronic device comprising between the emission face and the mass face, a thick peripheral wafer with at least one longitudinal side and one transverse side, at least one meander arrangement is contiguous with at least one side. longitudinal and / or a transverse side of the peripheral wafer thickness.

According to one embodiment, the electronic device comprising between the emission face and the ground face, a peripheral thickness wafer, at least one upper interface conductor which connects a meander arrangement to the first antenna dipole and / or at least one lower interface conductor which connects a meander arrangement to the ground face, is an outer track affixed against the peripheral thickness wafer.

According to one embodiment, the electronic device comprises at least one upper interface conductor which connects a meander arrangement to the first antenna dipole and / or at least one lower interface conductor which connects a meander arrangement to the mass face. , is in the form of a metallized hole or via, remote from the peripheral thickness wafer. According to one embodiment, the electronic device comprises a single meander arrangement, arranged substantially in line with the first antenna dipole on the emission face, and at a distance from this component in a longitudinal direction of the electronic device, perpendicular to the direction of transmission. 'thickness. According to one embodiment, the electronic device comprises at least two meander arrangements, arranged two by two substantially symmetrically in a longitudinal and / or transverse direction of the electronic device, perpendicular to the direction of thickness. According to one embodiment, the electronic device comprises at least two meander arrangements, two to two asymmetrical with respect to a longitudinal and / or transverse direction of the electronic device, perpendicular to the direction of thickness. According to one embodiment, an upper interface connector is said distal and connects a meander arrangement to the first antenna dipole, said distal upper interface connector being arranged in a longitudinal and / or transverse direction of the electronic device, perpendicular to the thickness direction, greater distance from the component relative to a so-called proximal lower interface connector which connects said meander arrangement to the ground face.

In one embodiment, the mass face under the lower level occupies between 80% and 100% of a surface area of the lower level of dielectric substrate.

In one embodiment, the lower level and / or the top-level dielectric substrate is made of dielectric material map low-cost, for example, is at least partially made of synthetic material ^'resistant thermo, for example flame retardant, such as resin and / or silicone and / or epoxy and / or carbon fiber material (aramid, fiberglass or the like).

According to one embodiment, the electronic device comprises at least one cap attached to the emission face so as to protect the electronic component. For example, the label comprises an attached cap, in the form of a pastille without bond and / or varnish and / or cover plate, at least the emission face and / or the peripheral wafer and / or the mass face of the substrate. having at least one unmasked area of access to the component.

According to one embodiment, the invention relates to a marked product which is rigidly fixed less an electronic device as evoked. This labeled product is at least partly metallic. For example, this marked product is part of or consists of a vehicle, for example an aircraft, in particular with a rotary wing.

According to one embodiment, the invention is an electronic identification system by radio frequency in the range of ultra-high frequencies (UHF), with a predefined maximum transmission power is of the order of 2 Watt ERP or 4 Watt EIRP.

This system comprises at least one electronic device as evoked, on at least one product to identify, and at least one radio frequency reader with a predefined maximum transmit power of the order of 2 Watt ERP or 4 Watt EIRP. For example, at least one identification device communicating radiofrequency waves with at least one radio frequency reader at a distance of the order of 1 to 2 meters. But other features and advantages of the invention emerge from the detailed description which follows and refers to the accompanying drawings.

In these drawings, FIG. 1 is a diagrammatic perspective view of an embodiment according to the invention of an RFID electronic device with substantially parallelepiped contour; FIG. 2 is a plan view from above of an antenna dipole transmission face according to the invention;

Fig. 3 is a top plan view of a meander-shaped asymmetric impedance adjusting arrangement layer according to the invention; FIG. 4 is a top plan view, respectively with a left half view and a right half view, in accordance with the invention, of a face of mass entirely covering on the left and partially covering on the right, respectively; FIG. 5 is a plan view from above of a double and symmetrical meander arrangement layer according to the invention;

Fig. 6 is a top plan view of a double and asymmetric meander array according to the invention;

FIGS. 7 and 8 are views similar to FIG. 1, which respectively illustrates (FIG. 7) an electronic device according to the invention affixed to a product marked with its optimized radiating field at the top and an electronic device (FIG. 8). according to the invention detached from its product to be marked with its radiating fields in the air (not optimized) with upper and lower diffusion;

FIG. 9 is a view similar to FIG. 1, of another embodiment according to the invention, of a substantially rectangular contour identification device, aimed at a reduction in the wafer size, accompanied by an increase in the effective surface of the impedance matching intermediate layer, in order to adjust the operating frequency of the antenna to different UHF RFID standards;

Figures 10 to 12 are other views similar to Figures 2 to 6, upper, intermediate and lower layers respectively of the embodiment of Figure 1 according to the invention; and

FIG. 13 is a schematic perspective view of an identification system according to the invention, with a series of electronic devices embedded in an aircraft whose equipment form marked products, and a series of contactless RFID readers arranged externally. and / or embedded. In the figures, we see reference directions X, Y and Z. These three directions define an orthonormal reference XYZ according to which the various constituents of the invention are described in their context. The direction X is arbitrarily termed longitudinal, especially if the constituents of the invention of elongate form have their main median, represented so that it is confused with this longitudinal direction X. The direction Y is arbitrarily called transverse, and the constituents of elongated shape have their median perpendicular to the longitudinal direction X, shown to be coincident with this transverse direction Y. Finally, the direction Z is arbitrarily called thickness or elevation, because the dimension of the components perpendicular to the X directions and Y, is shown to be confounded with this direction of elevation Z.

In FIGS. 1 to 13, reference numeral 1 generally designates an electronic radio frequency identification device (RFID) in the ultra-high frequency range (UHF). As regards the reference numeral 2, it generally designates a product to be marked using at least one electronic device 1.

The electronic device 1 is a transponder. It comprises a memory component 3, rigidly fixed on a support which is detailed below. In embodiments, the component 3 is a processor chip. In the examples, the component 3 has a large memory so that it can store a large amount of information. To respond to industrial applications, the component 3 is for example: a component 3 of the Ucode G2XM type from NXP which has 512 user memory bits, and is equipped with a TSSOP8 package, which is easy to solder; or

a component 3 of the IPJW15000-W1503 Monza 4 type from IMPINJ, with intrinsic capacitance of 970 fF and whose surface area is 590 pm 2 while its temperature range is extended from -40 ° C. to + 85 ° C.

The electronic device 1 of radio frequency identification (RFID) of one or more products 2, operates in the range of ultra-high frequencies (UHF).

This electronic device 1 comprises in a stack in a direction of thickness Z of the electronic device 1:

a higher level 4 of dielectric substrate and

a lower level of dielectric substrate. Typically, these substrate levels 4 and 5 are low-cost dielectric material boards. For example, the substrate levels 4 and 5 are partly made of heat resistant synthetic material, for example flame retardant, such as resin and / or silicone and / or epoxy and / or carbon fiber material (aramid, fiberglass or the like). In one embodiment, the layers, cards or substrate levels 4 and 5 are made of FR4 type epoxide.

In general, the invention does not involve the use of complex materials for substrates, such as dielectric ceramics. Their use may be necessary when the device is intended for an environment subject to factors incompatible with the low-cost substrates, in particular heat and hygrometry.

These substrate levels 4 and 5 form for the device 1: on the one hand, an external transmission face 6 extended on the upper level 4; and

- On the other hand a surface of outer mass 7, extended below the lower level 5. It is seen that it is by the lower level 5 that the electronic device 1 is fixed (e.g. in the XY plane) to the product 2 and marked. Other embodiments provide that the electronic device 1 is attached to the marked product 2 by a peripheral edge or edge thickness (in the planes XZ or YZ) of the device. Note that component 3 (or "chip") has a predetermined impedance, and is attached between the lower level and the higher level of dielectric substrate.

In particular on the emission face 6, is extended an antenna generally designated 8. This antenna 8 is bent, flat and short-circuited ("Planar inverted-F Antenna" or "PIFA").

This antenna 8 PIFA is connected on the one hand to the electronic component 3 by at least one short-circuiting element 9, to an upper conductive layer 10 of the antenna 8, on the external face of the upper level 4. In FIGS. 3 and 7-10 are provided two short-circuiting elements 9, in the form of metallized holes 11 or "vias", which pass through the upper level 4 in the direction Z, from one side to the other.

On the other hand, the component 3 is electrically connected or connected to a conductive layer 12 of grounding by at least one other shorting element 9, detailed below. This conductive layer 12 is extended under the external mass face 7 of the lower level 5 forming the base of the substrate.

Note that the electronic device 1 has an inner lower face 13 of the upper level 4 of the substrate, opposite to the emission face 6 in the direction Z, and another inner upper face 14 on the lower level of substrate 5 which is opposed to the ground face 7.

In the figures, the electronic device 1 comprises, in the direction of thickness Z, between the inner lower face 13 and the internal upper face 14, at least one impedance adjustment arrangement 15.

Each impedance adjustment arrangement 15 is in the shape of a "meander". That is, it is composed of a continuous series of contiguous sections of conductive material placed end-to-end. These sections are successively oriented in distinct directions, in the plane perpendicular to the direction of thickness Z. This forms a circuit at a time of great total length L and compact area. According to the embodiment of FIGS. 1, 3, 5, 7-8 and 11, the electronic device 1 comprises a single meander arrangement 15 disposed substantially in line with a first antenna dipole 16 on the emission face 6, remote from the component 3 in the longitudinal direction X. In FIG. 9, the electronic device 1 comprises a single meander arrangement 15, at the right of the antenna 8 and at the emission face 6, at a distance from the next component 3 the longitudinal direction X.

In FIG. 5, the electronic device 1 comprises two meander arrangements arranged two by two substantially symmetrically in the longitudinal direction X.

And in FIG. 6, the device 1 also comprises two meander arrangements, two to two asymmetrical relative to each other. to the longitudinal direction X while each being substantially symmetrical to the transverse direction Y.

The impedance adjustment function, in particular, of these arrangements is detailed below. To this end, each impedance adjustment arrangement 15 is meander-shaped with a predetermined compensation conductor length.

With the illustrated forms, such a length of the compensating conductor is substantially less than the sum of the successive dimensions along the X and Y directions of electrical circulation, of the different constituent segments of said meander impedance matching arrangement.

In FIG. 3 for example, this length L compensating conductor is slightly less than:

the product of an overall longitudinal dimension Lx of this arrangement measured in direction X,

by a value V (here, V = 7) of the number of trips of the arrangement 15 in the direction Y,

plus an overall transverse dimension Ly of this arrangement in the direction Y. It can therefore be written here that:

L <(Lx) x [V x (Ly)].

In fact, in FIG. 6 the length L (D) of the right-hand arrangement is less than the length L (G) of the left-hand arrangement, since this left-hand arrangement has a number of feeders. returns V = 7, while arrangement 15 on the left has a number of round trips V = 3. In FIG. 1, the meander arrangement 15 is on the one hand connected to the first dipole 16 of the antenna 8, by said upper interface conductor 9 which here is in the form of an outer track 17 affixed against a wafer Device Thickness Device 1. Actually this outermost track 17 is against the left transverse slice of the upper level 4 of substrate.

On the other hand, the meander arrangement is connected by at least one lower interface conductor 9 to the ground face 7. In Fig. 1, the single meander arrangement is connected to the ground face by a single lower interface conductor 9, in the form of an outer track 17 against a peripheral thickness wafer of the device 1. In fact, this lower outer track 17 is against the front longitudinal edge of the lower level 5 of the substrate.

5 and 6, where the device 1 has two (2) meander arrangements 15, the first arrangement (left) is similar to that of FIG. 1. While the second (right) arrangement 15 is connected to firstly to a second dipole 18 of the antenna 8, by a second upper interface conductor 9 in the form of an outer track 17. This track 17 is against the right transverse edge of the upper level 4 of the substrate. The connection between this second arrangement 15 and the conductor 7 of the ground plane is provided by a lower track 17 and on the longitudinal front face of the device 1, at the lower level 5 of the substrate.

In FIG. 1, it can be seen that the electronic component 3 is connected on the one hand to said first antenna dipole 16 by the metallic hole-shaped inner interface conductor 9 as well as on the other to the second dipole 18 8, by another internal interface conductor 9 also in the form of metallized hole 11 the upper level 4 of substrate thickness. According to this embodiment, the single meander arrangement forms a conductive layer affixed to the inner inner face In other embodiments, the meander arrangement is under the inner top face of the lower level 4 of the substrate.

In FIG. 1, the meander arrangement 15 has a substantially parallelepiped contour, with (at least one) dielectric notches 19 which open transversely in the transverse direction Y of the electronic device 1.

In other embodiments, the arrangement 15 has one or more notches 19 extended and each opening to a thickness wafer of the device 1, in the longitudinal direction X.

It goes without saying that embodiments of arrangements 15 comprise one or more notches 19, of different orientations. Some of these longitudinal and / or transverse notches 19 have dimensions in the XY plane which are clearly smaller than the width / length of the arrangement to which they belong, for example of the order of one half, one third of this width / length. . Also, notches 19 form an angle of between 0 ° and 90 ° with respect to one and / or the other of the X / Y directions.

According to the embodiments of FIGS. 1, 3, 5-8 and 11, the electronic device 1 comprises between the transmission face 6 and the ground face 7, at least one arrangement 15 contiguous to a peripheral thickness wafer of said device 1 The electronic device 1 comprising between the emitting face 6 and the ground face 7, a peripheral thickness wafer with at least one longitudinal side (left or right) and a transverse side (front or rear), at least one Meander arrangement 15 is contiguous with at least one of these sides respectively longitudinal (in the XZ plane) and / or transverse (in the YZ plane) of the peripheral thickness wafer.

In FIG. 1, an upper interface conductor 9 which connects the dipole 18 of the antenna 8 to the ground face 7, is an external track 17 affixed against the peripheral edge of thickness, on a transverse (right) side (in the plane YZ).

According to FIG. 1, an interface conductor 9 in the form of upper and transverse via 17 connects the meander arrangement 15 to the first dipole 16 and a lower and longitudinal interface conductor 9 connects this arrangement 15 to the ground face 7. In FIGS. 9-10 and 12, these conductors are in the form of metallized holes 11 or vias, and are spaced apart from the peripheral thickness wafer of the device 1.

In fact, an interface connector 9 is said distal if it connects an arrangement 15, for example to the first dipole 16 being arranged in the longitudinal direction X or transverse Y, away from the component 3. This is opposed to a 9 said proximal interface connector which connects an arrangement 15 for example to the ground face, being remotely (eg apart from the right in elevation, connection pads 20 of the component 3 to the antenna 8) of this component 3.

Comparing the embodiments on the left and right of FIG. 4, it can be seen that the lower conductor 10 of the mass face 7 under the lower level 4 occupies between 80% (on the left) and 100% (on the right) of a surface area of this lower level 4 of dielectric substrate. In the case where an outer track 17 is provided between the ground face 7, the lower conductor 10 has a fitting opening to a corresponding thickness wafer.

In FIG. 5, the electronic device comprises at least one cap 21 attached by the emission face on the upper face of level 5, so as to protect the electronic component 3. For example, this cap 21 is in the form of a tablet without glue and / or varnish and / or dielectric substrate cover plate. At least the emitting face 6 and / or the peripheral edge and / or the ground face 7 of the substrate have at least one unmasked zone 22 for access to this component 3. In the illustrated embodiments, this unmasked zone 22 is in the form of an emergent cavity which passes through the upper level 4 of the substrate, from one side to the other in the direction of thickness Z. The cap 21 is placed and arranged in this unmasked zone 22, as represented in FIG.

The invention aims to mark products 2 to which are rigidly attached at least one electronic device 1 as evoked. This marked product 2 is at least partly metallic. In FIG. 13, this marked product 2 is part of a vehicle, in this example a rotary wing aircraft 25.

In FIG. 13, the set of devices 1 collaborating with readers 23 form an electronic identification system 24 by radiofrequency in the ultra-high frequency (UHF) range, with a predefined maximum transmission power of the order of 2 Watt ERP or 4 Watt EIRP.

This system 24 here comprises several devices 1 as evoked, fixed at various locations on equipment 26 of the product 2 (25) to be identified.

The readers 23 have a predefined radio frequency maximum transmit power of the order of 2 Watt ERP or 4 Watt EIRP. Thus, an identification device 1 is able to communicate read / write with at least one of the radio frequency readers 23 at a distance D of the order of 1 to 2 meters or more.

Comparing FIGS. 7 and 8, it can clearly be seen that the radiofrequency emission spectrum of a device 1 according to the invention is distinct if this device 1 is attached to a product 2 (FIG. 7), that is to say say affixed on the product 2 thus marked with its radiant field PR (s) optimized in upper part, of the same electronic device 1 (Figure 8) according to the invention detached from its product to be marked with its field radiating in the air (not optimized) higher diffusion PR (s) and lower PR (i). The distance D obtained with the device 1 affixed to the product 2 in FIG. 7 is greater than the distance D 'without adaptation as illustrated in FIG. 8.

In fact, the adaptation, obtained by the meandering arrangement, between the antenna 8 and the component 3, is such that when ZA = ZP ^* , as the component 3 admits an impedance of ZP = RP type - jXP, it is sought, at a given frequency, that the antenna 8 whose impedance ZA = RA + jXA, is that RA + jXA = RP + j ^' XP.

We can recall the equation of telecommunications, (also called the Friis equation by the Anglo-Saxons), provides an order of magnitude of the radio power collected by a device 1 located at a distance D from a reader 23 emitting in free space. It should not be confused with the formula of Friis, used to calculate the noise factor of a system 24. In this respect, we can see the site: http://fr.wikipedia.org/wiki/%C3% 89quation of t% C3% A9l% C3% A9commu nications

It is an equation that is used enormously in RFI D which makes it possible to connect the different elements of an RFI system D such that:

The emitted power Pr of a reader 23;

The received power Pt of an electronic device 1; The gain Gr of the antenna of the reader 23;

The gain Gt of the antenna 8 of the electronic device 1;

- The distance "D" which is the reading distance between the antenna 8 and that of the reader 23; The wavelength λ where: λ = c / (f * Ver) where "c" is the celerity, that is to say the "speed" of propagation of a disturbance in a medium, without displacement of matter in air c = 3e8 ms-1; and

- "f" is the working frequency and "er" the permittivity of the medium in which one emits. Hence the Friis equation:

Or ; Pr = Pt * Gr * Gt * [Kl (4 * JTd)) * 2. may derive from this relationship the effective effective radiated PEIRP = Pt * Gt which is fixed by the authorities proper to each country. For example, the maximum power value emitted in Europe is 2W EIRP and 4 W ERP in the USA.

As explained, there is an adaptation of the device 1 when the impedance of the antenna 8 is equal to the combined impedance of the component 3: ZA = ZP *.

To conclude, let us outline an outline of specifications applied to embodiments of the invention.

It is sought to design a device 1, in the UHF range, which makes it possible to identify products 2, for example aeronautical-type equipment, embarked on board an aircraft (e.g., helicopter 25). These products 2 can be of different materials (composite, PVC, aluminum, etc.). It is sought to obtain the greatest reading distance "D" between the device 1 and the antenna of the reader 23, which will make it possible to identify it. In accordance with the applicable standard, is issued a power of 2W ERP.

The design or "design" of the antenna 8 and its (or its) arrangement (s) 15 must allow a good adaptation between the combined impedance of the component 3 and the impedance of the antenna 8. Since the device 1 must be identifiable if it is placed on metal surfaces, it must have a high gain. The difficulty overcome by the invention was to design a device 1 which, even placed on a metal surface, allows enough wave reflection, to be properly captured by an antenna of at least one reader 23.

After simulation, tests of antennas 8 with the following arrangement (s) were made, with 2.4 mm thickness and designed to identify metal surfaces.

The invention is nevertheless not limited to the exposed embodiments. Conversely, it includes all the equivalents of the characteristics described.

Claims

REVENDI CATIONS

An electronic identification device (1) for radiofrequency identification in a metallic environment; this device (1) comprising at least: a stack in a thickness direction (Z) of the device (1) of at least one upper level (4) of dielectric substrate and a lower level (5) of dielectric substrate , with on the one hand an emission face (6) on the upper level and on the other hand a ground face (7) under the lower level; an electronic component (3) having a user memory, having a predetermined impedance and being attached between the lower level (5) and the upper level (4); and an antenna (8) curved, flat and short-circuited (PIFA) extended on said emission face (6) and connected firstly to the electronic component (3) by at least one short-circuiting element (9) , and a conductive layer (12) for grounding on the other hand; this conductive layer (12) being extended on the mass face (7) of the lower level (5), characterized in that the electronic device (1) comprises, in the thickness direction (Z), between a lower face ( 13) of the upper level (4) opposite the emission face (6) and an inner upper face (14) of the lower level (5) opposite the ground face (7), at least one arrangement (15). meander-shaped impedance adjustment device with compensating conductive length (L); this meander arrangement (15) being connected on the one hand by at least one interface conductor (9) greater than a first antenna dipole (16) and secondly connected by at least one interface conductor ( 9) less than the conductive layer (12); while the component (3) is connected by internal interface conductors (9, 11) in the form of metallised holes (11) passing through the upper level (4) in thickness to said first dipole (16). antenna and secondly to a second antenna dipole (18).

Electronic device (1) according to claim 1, characterized in that said device (1) comprises at least one meander arrangement (15) in the form of a conductive layer affixed to one of the inner inner side faces of the upper level (4), or upper inner side of the lower level (5). of a substrate, with a substantially parallelepiped contour and at least one dielectric slot (19) emerging transversely and / or longitudinally respectively in a transverse direction (Y) / longitudinal direction (X) perpendicular to the thickness direction (Z) of the electronic device ( 1).

3. Electronic device (1) according to claim 1, characterized in that this device (1) comprising between the emission face (6) and the ground face (7), a peripheral wafer of thickness, at least one Meander arrangement (15) is contiguous with the peripheral thickness wafer.

4. Electronic device (1) according to claim 1, characterized in that this device (1) comprising between the emission face (6) and the ground face (7), a thick peripheral wafer with at least one longitudinal side and a transverse side, at least one meander arrangement (15) is contiguous with at least one longitudinal side and / or one transverse side of the peripheral thickness wafer.

5. Electronic device (1) according to claim 1, characterized in that this device (1) comprising between the emission face (6) and the ground face (7), a peripheral wafer of thickness, at least one upper interface conductor (9) which connects a meander arrangement (15) to the first antenna dipole (16) and / or at least one lower interface conductor (9) which connects an arrangement (15) meander to the mass face (7), is an outer track (17) affixed against the peripheral thickness wafer.

Electronic device (1) according to claim 1, characterized in that said device (1) comprises at least one upper interface conductor (9) which connects a meander arrangement (15) to the first dipole (16) and / or at least one lower interface conductor (9) which connects a meander arrangement (15) to the ground face (7), is in the form of a metallized hole (11) or via a distance from the peripheral thickness wafer .

7. Electronic device (1) according to claim 1, characterized in that this electronics (1) comprises a single meander arrangement, arranged substantially in line with the first antenna dipole on the emission face, and at a distance from the component in a longitudinal direction of the electronic device, perpendicular to the direction of thickness.

8. Electronic device (1) according to claim 1, characterized in that this device (1) comprises at least two arrangements (15) in meanders arranged in pairs substantially symmetrically in a longitudinal direction (X) and / or transverse ( Y) of the electronic device (1), perpendicular to the thickness direction (Z).

9. Electronic device (1) according to claim 1, characterized in that this device (1) comprises at least two arrangements (15) in meanders, two to two asymmetrical with respect to a longitudinal direction (X) and / or transverse ( Y) of the electronic device (1), perpendicular to the thickness direction (Z).

10. Electronic device (1) according to claim 1, characterized in that this device (1) comprises an upper interface conductor (9) which is said distal and which connects an arrangement (15) meandering to the first antenna dipole (16), said distal upper interface conductor (9) being arranged in the thickness direction (Z) at a distance from the component (3) in the longitudinal direction ( X) and / or transverse (Y) upper relative to a proximal said lower interface conductor (9) which connects said meander arrangement (15) to the conductive layer (12) of the ground face (7).

11. Electronic device (1) according to claim 1, characterized in that the conductive layer (12) of the ground face (7) under the lower level (5) occupies between 80% and 100% of a surface area of this lower level (5) of dielectric substrate.

Electronic device (1) according to claim 1, characterized in that the lower level (5) and / or the upper level (4) of the dielectric substrate is in low-cost dielectric material card, for example is at least part made of thermo-resistant synthetic material, for example flame retardant, such as resin and / or silicone and / or epoxy (FR4) and / or carbon fiber material (aramid, fiberglass or the like).

13. Electronic device (1) according to claim 1, characterized in that this device (1) comprises at least one cap (21) attached to the emission face (10) so as to protect the electronic component (3); for example, the device (1) comprises a cap (21), in the form of a pastille without glue and / or varnish and / or cover plate, at least the transmission face and / or the peripheral wafer and / or the mass face of the substrate having at least one unmasked area (22) for access to this component (3).

14. Product (2) marked to which is rigidly fixed minus an electronic device (1) according to one of claims 1 to 13, characterized in that the product (2) marked is at least partly metallic, for example this product (2) marked is part or consists of a vehicle, for example an aircraft, including rotary wing (25).

15. Electronic system (24) for identifying a radiofrequency labeled product (2) in the ultra-high frequency (UHF) range; this system (24) comprising at least one electronic device (1) according to one of claims 1 to 13, characterized in that at least one product (2) to be identified is arranged for read / write without contact with at least one radio frequency reader (23) allowing a predefined maximum transmission power of the order of 2 Watt ERP or 4 Watt EIRP; for example, at least one identification device (1) is arranged for radiofrequency communication with at least said radiofrequency reader (23), at a distance of the order of 1 to 2 meters.