MXPA00005597A - Pneumatic tyre with an antenna for radio transponder - Google Patents

Abstract

An annular apparatus is embedded in a substantially nonconductive elastomeric material (22) located within the toroidal region of a pneumatic tire (10). The apparatus is coaxially positioned with respect to the tire or wheel and preferably is embedded in the tire at its equatorial plane (EP), and includes a radio-frequency transponder system (30), including an integrated circuit chip (28), and optional sensors in the chip or associated with the chip. The integrated circuit chip (28) of the transponder system (30) has at least the capacity to transmit data relating to tire or wheel identification. The antenna (26) comprises a springy steel wire orfilament. Electrical leads (32) of the chips (28) are electrically associated with each end of the antenna (26).

Description

ANTENNA FOR TRANSPONDER RADIO FREQUENCY IN THE PNEUMATIC Technical Field The present invention relates to an apparatus and an antenna for electronically transmitting tire or wheel identification data or other radio frequency data. The apparatus includes a radio frequency transponder comprising an integrated circuit chip having at least sufficient data capacity to retain identification information for the tire or wheel. Other data, such as the inflation pressure of the tire or the temperature of the tire or the wheel at the transponder site, can be transmitted by the transponder together with the identification data. As illustrated by the references described below, it is known in the art to employ an annular antenna to transmit, by radio frequency, data from a transponder contained within the structure of a tire or tire and wheel assembly. In practice, however, it is very difficult to do this with an antenna built into the tire during the course of its manufacture. As much the tires of radial layers as those of superimposed layers, undergo a substantial diametral enlargement during the course of manufacture. Tires with superposed layers expand diametrically when inserted in a curing press, which typically has a bladder that forces the raw tire to the toroidal shape of the surrounding mold. Radial layer tires are subjected to diametral expansion during the process of shaping or construction of the tire and an additional diametral expansion during the course of curing. Any electronic circuits coupled to an annular antenna built into the tire must be able to ensure that its electrical connections survive this diametral enlargement of the tire during its manufacture. In addition, the annular antenna must be able to survive the repeated deformations that occur during use of the tire. It is convenient to interrogate or read the data contained within or transmitted by the transponder in any position around the circumference at 360 ° of the tire. A convenient feature of a transponder apparatus is a tire that is capable of transmitting tire pressure data if a pressure sensor is used in conjunction therewith. It is also convenient that the transponder be capable of transmitting information regarding the temperature of the tire at the transponder site.

Previous Technique Tire safety indicator means have been provided in the prior art to indicate when the floor contact portion of a tire is worn to the point where the floor contact portion or the tire should be replaced. See for example De Cicco in the U.S. Patent. No. 3,770,040. As the art has advanced, systems for verifying tire pressure and the like have been proposed wherein a transmitter and receiver are mounted on a vehicle body, and magnetically coupled inducer and inducer circuits are transported on the vehicle wheel to provide tire pressure check of the vehicle as described by Alien in the US Patent No. 4,588,978. Other devices for verifying the tire pressure have been proposed by Galasko et al., In the U.S. patent. No. 4,578,992, which illustrates a coil mounted on a tire that forms, with a capacitor, a passive oscillatory circuit. The circuit is energized by pulses supplied by a coil placed outside the tire and attached to the vehicle, and the frequency in the passive oscillatory circuit is varied with the tire pressure due to changes caused to the capacitance value of the capacitor. The frequency of the circuit is detected by a coil placed outside the tire and attached to the vehicle. Milheiser, in the U.S. patent. Do not. 4,730,188 illustrates the use of a passive integrated transponder that is connected to or embedded in an item to be identified and excited by an inductive coupling of an interrogator. Fiorletta, in the patent of the U.S.A. No. 5,289,160 illustrates a wireless tire pressure verification device, which warns a low pressure driver on one or more tires. Fiorletta, illustrates that a pressure transducer, transmitter and antenna are integrally housed and mounted on the stem of the tire. When the pressure transducer detects a pressure below a pre-selected pressure, the transmitter broadcasts a radio frequency signal that, upon detection by a receiver mounted on the vehicle, warns the user. In a preferred embodiment, the transmitter is a device that is interrogated periodically by an RF signal from a transmitter in the vehicle. In PCT applications O90 / 12474 and 90/01754, it is illustrated that electronic transponders can be embedded within or on vehicle tires and electromagnetically driven by signals from an interrogating coil. The request indicates that the transponder responds to drive by producing a shifting frequency that is modulated with synchronization pulses and identifying digital information and may also be used to include information regarding the condition and environment of the tire. Hettich et al., In the U.S. patent. No. 5,140,851, illustrate a circuit assembly for verifying air volume in vehicle tires that allows correction for tire temperature. The patent states that the measurement value of temperature and pressure of the tire is measured by a rotary receiver on the wheel, which is verified and the data is fed to a correction circuit that also receives a plurality of correction parameters. A corrected value for the temperature or for the air pressure in the tire is transmitted at the output of the correction circuit as a function of the connection parameters. PCT application O92 / 20539 provides an abnormal tire condition warning system comprising a housing, a band for mounting the housing in the tire lip, a detector for verifying the condition within the tire, circuits operatively connected to the detector to generate radial signals indicative of the condition of the tire, an energy source operatively connected to the circuits, a centrifugal switch and a receiver for the radio signals. Dunn et al., In the patent of the U.S.A. No. 4,911,217 discloses a system for radio frequency tire identification having an integrated circuit chip transponder. Pollack et al., In the patent of the U.S.A. No. 5,161,975, illustrates a tire having an integrated circuit transponder comprising a coiled antenna of small circumscribed area, as compared to the area circumscribed by the face of the tire, and acting as a primary winding of a transformer. The coil is planar in shape, and when placed between the inner liner and the carcass layer of the tire may include a pressure sensor. Brown and colleagues, in the patent of the E.U.A. No. 5,218,861, illustrates a tire having an integrated circuit transponder having an antenna coupled by electric or magnetic fields to the face of the tire. Koch et al., In the U.S. patent. No. 5,500,065 illustrates locating a verification device radially inward of the inner lining of a tire, somewhere in the crown portion of the tire.

Description of the Invention An object of the invention is to provide an apparatus that can be constructed in a tire, suffi ciently small so that it has no noticeable effect on the operation of the tire and is strong enough to withstand the millions of deformations to which it is subjected. a tire during its use in a vehicle. Other objects of the invention will be apparent from the following description and claims. Definitions The following definitions are provided to facilitate the reading of the specification and the understanding of the invention. "Heterodyne" refers to the additional sum and difference frequencies that are produced by mixing two alternating sinusoidal current sources. "Transmitter" refers to a radio frequency transmitter. "Receiver" refers to a radio frequency receiver. "Interrogator" refers to a transmitter-receiver decoder combination.

"Flow lines" refer to magnetic intensity and the direction of the magnetic intensity vector. "Transponder" refers to an RF energy receiver capable of transmitting coded information to an interrogator (digitizer). "Equatorial plane (EP)" refers to the intersected plane in the center line of the tire. "Radially" refers to a radial line from a tire axis to the circumference of a tire and its parallel lines. Brief Description of the Drawings Figure 1 illustrates a cross section of an RMT tire having the apparatus of the invention illustrated in the crown of the tire. Figure 2 illustrates a cutting portion of Figure 1, seen radially outwardly of the rim. Figure 3 illustrates a diagram of a possible apparatus configuration. Figure 4 illustrates a diagram of an alternate apparatus configuration. Figure 5 illustrates a tire building drum with a rubber strip, an integrated flake and an inner liner.

Figure 6 illustrates a side view of an alternative embodiment of a flake / antenna assembly. Figure 7 illustrates a bottom view of the assembly of Figure 6. Figure 8 illustrates a flake with terminals aligned with the carcass ply cords in a tire. Figure 9 illustrates an alternate configuration of the antenna of the invention. Best Mode to Carry Out the Invention Industrial Applicability An annular apparatus is provided to electronically transmit tire or wheel or other identification data. The apparatus comprises a transponder, which includes an integrated circuit chip and at least first and second electric conductors coupled to the chip. The flake, before externally induced radio frequency excitation, causes the data to be output sequentially from the flake as a voltage appearing between the first and second conductors. An antenna, which together with the transponder has an annular configuration 10 is coaxial with the tire or wheel. The antenna comprises an elastic steel wire and in an illustrated embodiment, a filamentary wire wound in a helix and having a wire diameter of .04 to .4 mm.

As used herein, first and second conductors may be a wire surrounding a tire, wherein the first conductor is the end of the associated wire or the end of the wire associated with a terminal of the transponder, and the second conductor is the end of the wire associated with the second terminal of the transponder. The apparatus is substantially circumscribed by non-conductive rubber and is located within the toroidal region of the tire. The transponder is embedded in non-conductive materials to avoid electrical conduction or significant derivation between flakes and the antenna that can be placed on the flake. The antenna portion has a conformation ratio that allows 150 to 2,000% elongation or more of the antenna. In the illustrated embodiment, the antenna portion is placed around EP of a tire where it is incorporated. Conductive rubber can be used to provide connection between various terminals of the antenna and transponder. The conductive rubber has a tensile modulus of 21.09 to 28.12 kg / cm2 (300 to 400 psi) at 50% elongation, an elongation of 270 to 350%, a maximum tensile strength of 126.54 to 147.63 kg / cm2 (1,800 at 2100 psi), rubber adhesion / brass coated steel wire of approximately 50 Newtons force (75% rubber coverage) and T90 in 30 minute cure time. An antenna designed to receive a signal from a transmitting device to electronically activate the electronic circuit of the chip and to transmit data from the electronic circuit to a receiving device is also provided. Also provided is a tire comprising at least two parallel annular faces, carcass layers wound around the faces, surface or portion of contact with the floor arranged on the carcass layers in a crown area of the tire, sidewalls placed between the contact portion with the floor and the faces, and a system of detection disposed radially inwardly of the inner liner. The detection system comprises the apparatus of the invention as described. Description of the Invention Now with reference to Figure 1, there is illustrated a tire 10 incorporating a transponder system 30, or signal generator, which can be used to provide tire data such as the inflation pressure inside the tire, the tire temperature, and the tire temperature. tire, and tire identification. As is conventional in the art, the tire is made using at least one pair of annular faces 12, on which at least one shell layer 16 is wrapped. The bands 18 are placed on the carcass ply 16 in a crown area. of the tire, and the contact portion with the floor 20 is placed on the strips 18. The side walls 23 are placed between the contact portion with the floor 20 and the faces 12. In the illustrated embodiment, the tire also has a lining interior 14 which is positioned radially below the carcass ply 16. The pneumatic illustrated is a medium radial truck tire (RMT = Radial Medium Truck), but those skilled in the art will recognize that the apparatus of the invention may have utility in tires for passenger vehicles, or any tire for which data is required regarding the history or current condition of a tire. A tire, depending on the type, can have up to four pairs of faces, up to twelve layers of carcass or up to twelve bands. With reference also to Figure 2, in the illustrated embodiment, the transponder system 30 is placed under the center of the floor contact portion, ie in the equatorial plane (EP) of the tire and radially below the tire layer. housing 16 and inner lining 14. The transponder system 30 comprises one or more chips of integrated circuits 28, antenna 26 and any auxiliary components required to obtain different types of data that may be desired, such as pressure detectors and the like. It is considered that this location on the tire provides the most accurate data, and makes tire data more easily accessible, whether the tire is mounted on a vehicle or stacked in a warehouse, since the data can be recovered by carrying an interrogator near the floor contact portion in any part of the floor contact portion around the 360 ° circumference of the tire. The transponder system 30 is similar to that illustrated in U.S. Pat. Nos. 5,181,975 and 5,218,261 issued to The Goodyear Tire and Rubber Company, and commonly assigned records of agent Nos. DN 1997-192, 1997-194 and 1997-195, which provide identification data for the tire, and can be used to verify the tire pressure, tire temperature and the like. In the illustrated embodiment, the transponder flakes 2 to 6 are circumscribed in a hard plastic package containing all the circuits required to activate each of the flakes. The flake pack used in the illustrated embodiment is prepared by the inventors by Phase IV Engineering.

The antenna portion 26 can comprise any metal that provides sufficient conductivity to maintain an electrical circuit under the conditions where a tire is employed, and can be pulled to a small diameter. The rubber of a tire will surround the antenna wire when the tire is molded. Due to the expansion steps required in the construction of the tire, the antenna 26 can be made of elastic wire 6a capable of the type of expansion required in the construction of the tire. The wire can be helically wound, folded to provide a corrugated wire, or otherwise twisted or bent such that substantial expansion of the wire is possible when required. In the illustrated embodiment, the antenna is a spring wherein the spring helix has a length of lay equal to the diameter of the wire up to about 5 times the diameter of the wire. Consistent with the description in the U.S. patent. No. 5,279,695, the preferred wire used for the antenna of the invention is commonly referred to as carbon steel or carbon steel, which is also referred to as high carbon steel, ordinary steel, direct carbon steel, and carbon steel. simple. Examples of this steel are grades 1070 and 1080 of high carbon steel from the American Iron and Steel Institute (ASI 1070 and 1080). This steel owes its property primarily to the presence of carbon without substantial amounts of other alloying elements. The patent of the U.S.A. No. 4,960,473 discloses some preferred steel alloys and a process for making steel filaments that can be used in this invention. Those skilled in the art will recognize that other steels with higher carbon content and containing microalloying elements such as chromium and boron can also be used. As an alternative embodiment, the inventors here speculate that copper-coated steel will provide an antenna wire with particularly improved conductivity. Brass is a copper and zinc alloy that may contain other metals in minor variant quantities. The alaton, which contains from 63 to about 99% copper and from about 1 to about 37% zinc, is generally used to coat filaments in the manufacture of filaments and cables for reinforced rubber articles. It is usually preferred that the brass contain from about 62 to 75% by weight of copper and from 38 to 25% of zinc. Brass-iron alloys as described in U.S. Pat. No. 4,446,198, can be used as well as other coatings, for example zinc.

The helical antenna can be manufactured using a spring production apparatus, such as a Torrin W-100 model. The finished spring can also be annealed at 260 ° C for one hour to relax the spring to improve handling during assembly. The spring can be produced with various total diameters, preferably 0.4 to 2 mm, with about 1 mm being preferred. The wire used in the antenna portion 26 can have any diameter suitable for a specific application. In normal use, it is considered that wire diameters from 0.4 to 4 mm will have general utility. Preferably, the wire diameter will be in the range of .06 to .2 mm in tires for medium and radial passenger trucks (RMT). In the illustrated embodiment, the wire has a diameter of .15 mm. During the construction of a tire, there are three expansion changes within the tire structure, which together cause the tire to expand from 128% to 133% from its size on the drum construction drum, see Figure 5. A antenna with an expansion of 150% to 2,000%, resistance 200% to 1,000% will have utility of the invention. The wire construction employed in the illustrated embodiment can provide an antenna design expansion as much as 1, 000% or more. To minimize the strength of the wire portion of the antenna, in the illustrated embodiment, approximately .60 m (two feet) of spring wire is stretched to cover 1.8 meters (6 feet) of the circumference of the tire. The antenna portion 26 can be provided, in the illustrated embodiment, in one to three windings around the tire. Although a sufficient signal can be obtained with a winding of the antenna portion 26, the signal is reinforced as additional windings are added since the amount of current developed depends on the number of magnetic focus lines that are located by the antenna in accordance with the Ampere law. The efficiency of the antenna can also be improved by increasing the thickness of the brass coating on the antenna wire or by using copper-coated steel on the antenna wire. In the illustrated embodiment, the flake 28 and the antenna 26 are contained within non-conductive rubber strips 22, radially inward of the inner liner 14. The non-conductive rubber strip 22 can be 1.27 to 10.16 cm wide (1 / 2 to 4") and in the illustrated mode it has an approximate width of 2.54 cm (1"). With reference to Figure 2, in the illustrated embodiment, two windings of antenna wire 26 are employed. A winding passes over the chip 28 but is isolated from the chip 28 by a layer of high-isolation epoxy 24. Now with reference to Figure 3, in an alternate distribution of the apparatus, two antenna windings 26 are achieved at cutting the terminals 32 of the integrated flake 28 and electrically connecting, such as by welding or embedding in conductive rubber, a first end 34 of an antenna wire 26 through terminals 32 and embedding the second end 36 in a conductive rubber 40, and a second antenna wire 26 a is placed in the same way through terminals 32a with a first end 34a that is electrically connected to terminals 32a and a second end 36a embedded in conductive rubber 40. A section of antenna 38 it can be continuous on the conductive rubber 40 or it can be cut and connected in the section of the antenna 38 for ease of construction. Those skilled in the art will recognize that the extra winding of the antenna 26 can be coiled away from the flake 28, instead of being placed on the flake 28. Compare Figures 2 and 3. Those skilled in the art will recognize that the conductive rubber it can be used whether an electrical connection is required between the antenna and the flakes or between portions of the antenna. In an alternate placement or distribution, as illustrated in Figure 4, two separate conductive rubber strips 40 may be employed to provide electrical connection between the two ends of the antenna 26 and the two sets of terminals 32. In such embodiment, the wire of antenna 26 can be continuous. When a conductive rubber matrix 40 is used, it is preferred that a rubber matrix having a resistivity of 0.1 to 100 ohm.cm was used. In the illustrated embodiment, the rubber matrix 40 has an electrical resistivity in the range of 5 to 50 ohm.cm, and in the specific embodiment has a resistivity of 7 ohm.cm. When rubber is stretched, its resistivity increases and the resistivity of 7 ohm.cm for the illustrated mode is obtained in the unstretched rubber. When stretched to 17%, the resistivity in the conductive rubber in the illustrated embodiment is approximately 10 ohm.cm. Epoxy used to isolate the flake in the illustrated mode is Dexter / Hysol FP4323. The rubber used to isolate the flake is a non-conductive rubber that has a low charge, in the range of 0 to 10 PHR of non-conductive carbon black. Insulating rubber must have properties that are consistent with its use in the tire. The insulating rubber used in the illustrated modality has a tensile modulus of 87.17 to 101.23 kg / cm2 (1240 to 1440 psi), (an elongation at break of 585 to 785%, a Shore A hardness of 44 to 48%, a 50% modulus of 4.57 to 5.62 kg / cm2 (65 to 80 psi) a T90 of 7 to 16 minutes and specific gravity (sg) of 1.04 to 1.09. Examples of insulating rubbers and conductors that may be employed in the invention are described in the US patent application. No. 08 / 814,957 filed March 10, 1997. Now with reference to Figures 6 and 7, in an alternate embodiment of the chip 28 of the invention, the chip 28 comprises a pressure detector 64, in addition to other circuits described above. and has contacts 62 on the opposite side of the flake 28a from the pressure sensor 64 and epoxy walls 66 that divide the bottom of the flake 28a into sections. The channels 68 between the walls 66 provide a route for helical winding of the antenna 26 to pass on or near the flake 28a and contacts 62, while insulating the different windings of the antenna 26 from each other and from the flake 28a. The contact 62 may preferably be copper and may be flat or have a notch or hook or some other means for hooking the antenna 26 to help maintain contact. With reference to Figures 3 and 5 in the illustrated embodiment, when the tire is manufactured as a non-conductive rubber layer 22, with an approximate width of 2.54 cm (1"), it is placed around the center of the construction drum. 28 is placed on the non-conductive rubber and the antenna 26 is placed around the rubber strip 22 in a loop, and the antenna 26 is electrically connected to each of the transponder terminals 32. The inner liner is placed on the antenna and the transponder, 360 ° around the tire, isolating the apparatus from the carcass ply and the web structure which subsequently are added to the building drum.Now with reference to Figure 8, it has been found that in some tire constructions , aligning the flake 28b of the invention and its terminals 32 with ropes 82 in a carcass layer during construction of the tire, reduces the stress on the flake and its terminals 32, because the flake 28b runs with a to rope 82 when the strings do pantograph during construction, instead of pulling between two adjacent strings. This helps prevent splitting of the chip or separate the terminals of the antenna during the expansion stage of the tire construction. For example, if the lacquer 28b is installed in a tire with superimposed layers, where the reinforcing cords are at an alpha angle of 58 ° with respect to the tire centerline, the longitudinal direction of the lacquer pack and its terminals opposite are aligned at an angle of 58 ° with respect to the center line of the tire. Likewise, in a radial tire wherein the carcass cords have an alpha angle of 90 ° with respect to the tire center line, the flake 28a and its opposite terminals 32 will be aligned at a 90 ° angle with respect to the centerline of the tire. The pantograph action of the carcass cords during construction of a radial tire is not as pronounced as the pantograph action of the carcass cords in a tire of superimposed layers during construction, but aligning the carcass 28b with the carcass cords 82 can reduce stress on the lacquer 28b and terminals 32 on any tire where it is used. The tire of another form is constructed in a manner known to those skilled in the art. With reference to Figure 9, it has been found that the interrogator response can be improved if the impedance of the antenna closely matches the impedance of the transponder, ie the impedances can correspond in such a way that the antenna uses only the energy required to activate the transponder. The impedance of the interrogator and transponder is coupled using a ferrite core 96 to step up or down the voltage of the transponder 92 using magneto wire windings 97a, 97b wrapped around the ferrite core 96. According to this, the terminals 98a and 98b connect the opposite ends of the windings 97a with opposite ends of the antenna wire 91, and the terminals 98c and 98d connect the opposite ends of the turns 97b with the flake 94. In the illustrated embodiment, the detector pressure 97 is located on the same circuit board as the flake 94. As will be apparent to those with skill in the specialty, the function of the transponder and the antenna in this embodiment and its construction using conductive rubber may be substantially as in the previous modalities of the antenna described here. Due to the improved response, the antenna apparatus only requires comprising a single wire winding 91. In the illustrated embodiment of Figure 9, the transponder package is prepared by Phase IV Engineering of Boulder, Colorado, using a ferrite core with thickness of .1524 cm (.06") having an outside diameter (OD) of .5842 cm (.23") and an inside diameter of .3048 cm (.12") cat. No. 5975000101, available from Fair-Rite Products Corp., One Commercial Row, Allkill, NY 12589. The primary coil 97a is optimized to 19 windings and the secondary coil 97b is optimized to 80 windings, using 38 gauge copper magnet wire when a coated spring antenna wire is used with brass 91.

In the embodiment illustrated, when the transponder system 30 is reached by an interrogator, the interrogator is designed to read the return signal from the lag 24. The interrogator transmits to a specific radio frequency and the lacquer responds by stepwise descending the signal frequency to transmit half of the return explorer frequency. The scanner frequency is heterodyned against the signal frequency that produces a difference sideband to reinforce the signal response. While the invention has been specifically illustrated and described, those skilled in the art will recognize that the invention can be modified and practiced in a variety of ways without departing from the spirit of the invention. The invention is limited only by the following claims.

Claims (11)

1. CLAIMS 1. A tire comprising at least two parallel annular faces, carcass layers wound around the faces, a portion in contact with the floor and placed on the carcass layers in a crown area of the tire, side walls disposed between the contact portion with the floor and faces, and a detection system disposed radially below the carcass layer and the inner liner, the detection system comprises an apparatus for transmitting tire data comprising: a transponder for responding to signals predetermined ones that activate a response signal for transmitting data and identifying information, a flake associated with the transponder having at least sufficient capacity to transmit pressure data, tire temperature data and identification information for the tire, and the characterized antenna because it comprises elastic wire associated with the terminals of the transponder.
2. 2. The tire according to claim 1, characterized in that the antenna is formed in a loop around the EP of the tire.
3. 3. The tire according to claim 1, characterized in that the antenna comprises monofilament steel wire having a diameter of .04 to .4 mm.
4. 4. Annular apparatus for electronically transmitting identification data of tire or rim or others, the apparatus comprises: a transponder that includes an integrated circuit chip and at least first and second electric terminals coupled to the chip, the chip before excitation of radio frequency induced externally by an interrogator, causes data to be output sequentially from the chip as a voltage appearing between the first and second terminals; and an antenna with which the transponder is annular in configuration and which is coaxial with the tire or wheel, characterized in that the antenna comprises elastic wire associated with the terminals of the transponder.
5. 5. - The annular apparatus according to claim 4, characterized in that it is located within the toroidal region of the tire or on the radially outer side of the rim of the wheel, and characterized by being substantially circumscribed by non-conductive rubber.
6. 6. The annular apparatus according to claim 4, characterized in that the transponder is embedded in non-conductive materials to avoid electric conduction of significant bypass between the flakes and the antenna
7. 7. The annular apparatus according to claim 4 characterized in that the terminals in the circuit flap comprise contact and the flake has non-conductive walls on one side of the flake providing channels for receiving elastic wire antenna
8. 8. The annular apparatus according to claim 4, characterized in that transformer matches the impedance between the antenna and the transponder
9. 9. An antenna for receiving a signal from a transmitting device for electronically activating an electronic circuit containing a transponder and for transmitting data from the electronic circuit to a receiving device, characterized in that the antenna comprises elastic wire associated with the transponder terminals.
10. 10. The antenna according to claim 9, characterized in that the wire comprises monofilament wire having a diameter of .04 to .4 mm.
11. 11. The antenna according to claim 9, characterized in that a transformer corresponds the impedance between the antenna and the transponder. 12. - The antenna according to claim 9, characterized in that the elastic wire comprises a helix having a length of laying equal to the diameter of the wire at about 5 times the diameter of the wire. 13. - The antenna according to claim 9, characterized in that the helix has a laying length of 0.3 mm per winding.