Patent Publication Number: US-10777892-B2

Title: Antenna

Description:
This nonprovisional application is a continuation of International Application No. PCT/EP2017/055020, which was filed on Mar. 3, 2017, and which claims priority to German Patent Application No. 10 2016 203 690.4, which was filed in Germany on Mar. 7, 2016 and to German Patent Application No. 10 2016 209 332.0, which was filed in Germany on May 30, 2016, and which are both herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to an antenna for wireless radio communication. The antenna is in particular a component of a hearing device. The invention further relates to a method for manufacturing an antenna and a hearing device comprising an antenna. The hearing device is preferably a hearing aid. 
     Description of the Background Art 
     Persons who suffer from a reduction in hearing ability usually use a hearing aid. In this case, an ambient sound is usually detected by means of an electromechanical acoustic transducer. The detected electrical signals are processed by an amplifier circuit and introduced into the ear canal of the person by a further electromechanical transducer. Various types of hearing aids are known. The so-called “behind-the-ear devices” are worn between the skull and the auricle. In this case, the amplified sound signal is introduced into the ear canal by means of a sound tube. A further common design of a hearing aid is an “in-the-ear device” in which the hearing aid itself is inserted into the ear canal. Consequently, the ear canal is at least partially closed by this hearing aid, so that, apart from the sound signals generated by the hearing aid, no other sound can penetrate into the ear canal or only to a greatly reduced extent. 
     If the person suffers from a hearing impairment in both ears, a hearing device system with two such hearing aids is used. Here, each of the ears is assigned to one of the hearing aids. In order to enable spatial hearing for a person, it is necessary that the audio signals detected by one of the hearing aids are provided to the other hearing aid. Here, the head of the person acts as damping in high-frequency transmissions, which is why the transmission rate between the hearing aids is limited. In addition, a transmit power is limited because of the limited energy storage of the hearing aids. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an antenna for wireless radio communication, as well as a particularly suitable method for manufacturing an antenna and a particularly suitable hearing aid comprising an antenna, wherein in particular transmission quality and reception quality are improved, and wherein preferably a power requirement and/or a space requirement are reduced. 
     The antenna is suitable, in particular provided and/or designed, to be used in wireless radio communication. In other words, the antenna is used for wireless radio communication. Suitably, the antenna is part of a hearing device. For example, the hearing device is an earphone or comprises an earphone. However, the hearing device is particularly preferably a hearing aid. The hearing aid is used to assist a person suffering from a reduction in hearing ability. In other words, the hearing aid is a medical device by means of which, for example, partial hearing loss is compensated. The hearing aid is, for example, a “receiver-in-the-canal” hearing aid (RIC), an in-the-ear hearing aid, an “in-the-canal” hearing aid (ITC), or a “completely-in-canal” hearing aid (CIC), hearing aid glasses, a pocket hearing aid, a bone conduction hearing aid, or an implant. The hearing aid is particularly preferably a behind-the-ear hearing aid, which is worn behind an auricle. 
     The antenna has a coil core extending along a longitudinal direction. The coil core has a number of turns, which are made of an electrically conductive material, such as copper-nickel, aluminum, or copper. In particular, the turns are made of enameled wire, such as a copper enameled wire or a copper-nickel enameled wire. In this case, the turns surround the coil core, for example, circumferentially along the full extent in the longitudinal direction. Especially preferably, however, the coil core projects on at least one side, preferably on two sides, with respect to the turns in the longitudinal direction. For example, the number of turns is between 2 turns and 200 turns, between 10 turns and 150 turns, between 20 turns and 100 turns, between 40 turns and 80 turns, and, for example, substantially equal to 60 turns, wherein, for example, there are deviations of 5 turns, 2 turns, or no turn. The turns expediently extend substantially in a mutually parallel plane, which is perpendicular to the longitudinal direction, and/or all turns are preferably formed next to each other. In other words, in particular, the turns are made in one piece from a component part, preferably from a wire, such as the enameled wire. Suitably, the turns are electrically contacted with electronics. 
     The antenna further has a planar first shield, which is arranged on an end face of the coil core, wherein the end face in particular forms a boundary of the coil core in the longitudinal direction. The first shield extends substantially in one plane, in particular along a spatial direction. The first shield thus extends at least along a surface whose curvature is relatively low or 0 (zero). At least the main dimension of the first shield in one, preferably two directions is in particular at least two times, preferably five times, or more than ten or twenty times greater than in another spatial direction. The directions are expediently perpendicular to each other. Preferably, the surface of the first shield is smooth. 
     The first shield is located on the end face of the coil core and is thus offset with respect to the coil core in the longitudinal direction. Suitably, when projected onto the first shield in the longitudinal direction, the end face is completely or at least partially surrounded by the first shield and is thus imaged by it. In other words, a projection of the coil core in the longitudinal direction is at least partially, preferably completely, covered by the first shield. The shape of the first shield is, for example, round, rectangular, or otherwise configured. The first shield extends at an angle to the longitudinal direction of the coil core. In other words, the plane within which the shield is located encloses an angle to the longitudinal direction that is different from zero (0). In other words, the plane is not parallel to the longitudinal direction. The first shield is made of a ferrimagnetic and/or ferromagnetic material. For example, the first shield is made of the same material as the coil core. 
     Due to the first shield, the transmission quality and reception quality of the antenna are improved, because with an inductive transmission with a constant antenna volume, the ratio of the length of the antenna to its diameter determines the performance and thus the quality of the antenna. The length of the antenna is increased because of the first shield, wherein the diameter surrounded by the turns is not increased. In fact, due to the first shield, the magnetic field lines are directed so that they enclose an angle with respect to the longitudinal direction. In other words, the magnetic field feedback is changed due to the first shield. However, this effect is relatively weak compared with the increase in quality due to the extension of the magnetic field lines in the ferromagnetic or ferrimagnetic material of the first shield. In this case, due to the angling of the first shield with respect to the longitudinal direction, a space requirement in the longitudinal direction is reduced, so that a relatively compact antenna is provided, which can thus also be used in a hearing device. 
     For example, if the antenna is used in a hearing device, audio signals and/or setting data can be transmitted by it, for example, between two hearing devices, each of which has an antenna of this kind. Alternatively, for example, audio data and/or setting data are transmitted between a remote control and the hearing device having the antenna. Due to the improved quality, it is not necessary to operate the antenna with a relatively high power, which is why a power requirement is reduced. In particular, the antenna is operated with a power between 100 μW and 100 mW. Preferably, the effective antenna area is between 500 mm 2  and 6000 mm 2 , and the inductance is preferably between 10 μH and 150 μH. 
     In particular, the antenna can be used for inductive radio communication. Preferably, the frequency range is between 1 kHz and 300 MHz, and particularly preferably between 100 kHz and 30 MHz. For example, the frequency range is between 2 MHz and 5 MHz and, for example, equal to 3.2 MHz. The first shield preferably has a length λ/4 with respect to a wavelength λ selected for radio communication, wherein material quantities such as a permittivity c and/or a permeability μ R  are expediently taken into account. For example, the antenna is used in addition to an inductive power transfer or power transfer that uses radio waves. In other words, power, which is used, for example, to charge an energy storage, is transmitted by means of the antenna. In particular, this use occurs when the antenna is part of the hearing device. 
     For example, the first shield is arranged at a distance of less than 300 μm, in particular less than 100 μm, or preferably less than 30 μm, to the end face of the coil core. The distance in this case is, for example, greater than 10 μm or 50 μm. Particularly preferably, however, the first shield adjoins the coil core without a gap. In particular, the first shield is electrically contacted with the coil core. Due to the relatively small distance, in particular due to the absence of a gap in the gap-free system, the formation of the magnetic field lines is further improved, which is why the quality of the antenna and thus its figure of merit are improved. In addition, the power requirement is reduced. For example, the first shield is integrally connected to the coil core, in particular by means of gluing or soldering. Alternatively, other fixing components can be are used, such as clips or the like. In this way, assembly is simplified and a space requirement is further reduced. 
     For example, the first shield is mortised with the end face of the coil core. In other words, either the first shield or the end face of the coil core has a tenon which is inserted or engages in a corresponding recess of the end face or the first shield. In this way, a shift of the first shield with respect to the coil core is prevented, which increases robustness. Preferably, the coil core comprises the tenon and thus engages in a corresponding recess of the first shield. Suitably, the tenon is reduced in cross section, in particular with regard to the cross section of the coil core in the region of the turns. In other words, the coil core is configured as step-like in the region of the end face, wherein the height of the step preferably corresponds substantially to the thickness of the first shield. Expediently, the size of the recess of the first shield corresponds to the reduced cross section of the coil core and is expediently smaller than the cross section of the coil core, with the exception of the tenon. Due to this, over-insertion of the coil core into the recess of the first shield is avoided, which further simplifies assembly and increases robustness. In a further alternative, the first shield is placed substantially flush on the end face of the coil core or at least arranged there. In other words, the first shield and the coil core have no mutually corresponding components, which interlock, for example. Thus, manufacturing of the first shield and the coil core is simplified. 
     For example, the shield has a thickness between 0.05 mm and 0.7 mm. In this case, the thickness in particular designates an extent of the first shield perpendicular to the plane in which the planar first shield extends, and/or which is parallel to the longitudinal direction. For example, the thickness is between 0.1 mm and 0.3 mm and preferably equal to 0.2 mm. Particularly preferably, the first shield is provided by means of a foil and is thus sheet-like. The first shield is expediently designed to be flexible, in particular elastically deformable, which simplifies installation of the antenna, in particular in a hearing device. If the first shield is created by means of a foil, manufacture is also simplified. 
     The shield can extend at an angle between 45° and 135° to the longitudinal direction, therefore, to the longitudinal direction of the coil core. In other words, the longitudinal direction and the plane in which the planar first shield extends enclose an angle between 45° and 135°. Particularly preferably, the angle is between 60° and 120° and suitably between 80° and 100°. For example, the first shield is arranged substantially at right angles, therefore, at an angle of 90°, to the longitudinal direction, wherein there is, for example, a deviation of up to 10°, 5°, 2°, or 0°. In other words, the antenna is at least partially configured substantially L-shaped. Due to the relatively large angle, the space requirement of the antenna in the longitudinal direction is relatively small and is substantially dictated solely based on the extent of the coil core. Thus, the antenna can also be arranged in a restricted space, as is the case, for example, with a hearing device. In addition, parts of the antenna can be arranged in regions that would otherwise not be usable. 
     The material of the first shield can have an electrical conductivity that is less than 10 6  S/m (Siemens per meter). Preferably, the electrical conductivity (a) is less than 100 S/m and, for example, between 1 S/m and 50 S/m, between 5 S/m and 20 S/m, and substantially equal to 10 S/m, wherein there is, for example, a deviation of 5 S/m, 2 S/m, 1 S/m, or 0 S/m. Due to the relatively low electrical conductivity, formation of eddy currents in the first shield is reduced, which reduces the power loss. Alternatively or in combination, the magnetic permeability (μ R ) of the first shield, which is a ferromagnetic or ferrimagnetic material, is greater than 5. For example, the magnetic permeability is greater than 100 and particularly preferably greater than 200, 500, or 1000. In this way, formation of the magnetic field line by the first shield is relatively efficient. Expediently, the electrical conductivity is less than 10 6  S/m and the magnetic permeability greater than 5, and suitably the material of the first shield has an electrical conductivity of substantially 10 S/m and a magnetic permeability greater than 200. For example, the material of the first shield comprises a ferrite, therefore in particular an oxidized iron, and, for example, MnZn ferrite. Suitably, the material of the first shield, however, at least the ferrite, is a foil or forms at least one foil. In other words, the ferrite is present in foil form. This is also applied, for example, to a further component of the first shield, or the first shield is formed by a foil of this kind. 
     The antenna can have a first layer, which is arranged on the first shield&#39;s bottom side facing the coil core. In particular, the first layer is arranged substantially in the same plane as the first shield or a plane parallel thereto. Expediently, the first layer is connected to the bottom side. The first layer is made of a material having a magnetic permeability of μ R  less than 1000. In particular, the permeability is less than 100 and preferably less than or equal to 10 or less than or equal to 2. Preferably, the material of the first layer is different from that of the first shield. The first layer is in particular arranged partially on the bottom side of the first shield or arranged over its entire surface. In this case, however, the first layer is particularly preferably omitted in the longitudinal direction in the region of a projection of the end face of the coil core on the first shield. At a minimum, the region of projection of the end face in the longitudinal direction on the first shield is free of the first layer, irrespective of the size of the first layer. In other words, the first layer is omitted at least there. For example, the circumferential extent of the first layer is substantially equal to the circumferential extent of the first shield. Alternatively, the first shield overlaps the first layer at the edge or vice versa. 
     Due to the first layer, propagation of the magnetic field lines from the bottom side of the first shield toward the coil core is reduced, which substantially suppresses magnetic field feedback, which is why antenna efficiency is increased and thus a power requirement is reduced. In addition, shielding is provided due to the first layer, so that any electrical and/or electronic components arranged on the bottom side of the first shield are not or only slightly disturbed due to the magnetic fields. Also, such components during operation do not interfere with a signal-to-noise ratio of the antenna or interfere with it only to a relatively small extent. In particular, due to the first layer any magnetic fields are shielded, which are caused, for example, due to a current-carrying electrical conductor, such as a trace of a printed circuit board, which is arranged between the bottom side and the coil core, so that they contribute relatively little to antenna interference. 
     For example, the material of the first layer is a paramagnetic material and thus has a permeability greater than 1 (μ r &gt;1). Alternatively, the material is a diamagnetic material and has a permeability between 0 and 1 (0≤μ R &lt;1. In this way, propagation of magnetic field lines away from the bottom side of the first shield is avoided relatively efficiently. Alternatively or particularly preferably in combination therewith, the electrical conductivity of the material of the first layer is greater than 10 6  S/m (Siemens per meter) and particularly preferably greater than 10 7  S/m. Preferably, the permeability of the first shield is greater than the permeability of the first layer and the electrical conductivity of the material of the first layer is greater than the electrical conductivity of the first shield. As a result, eddy currents are generated substantially only in the first layer, whereas the magnetic field lines are drawn into the first shield and thus substantially run there. Due to this, the sensitivity of the antennas is increased. The figure of merit of the antenna is also relatively high if a metallic further component, in particular of any hearing device, e.g., an electromechanical sound transducer (microphone), is arranged in the region of the bottom side, because there are essentially no eddy currents in the first shield and thus no eddy current losses arise. 
     Expediently, the material of the first layer is an aluminum or a copper, for example, pure aluminum or pure copper, or an aluminum alloy or copper alloy. In an alternative, the first layer is made of or comprises a low-permeability iron, a cobalt, a nickel, or a low-permeability stainless steel, such as MAGNADUR 3952, which has a permeability ≤1.02. In a further alternative, the material is an alloy comprising, for example, copper, aluminum, low-permeability iron, low-permeability stainless steel, cobalt, or nickel. Particularly preferably, the first layer is made of a diamagnetic copper or a paramagnetic aluminum. These two materials meet the requirements and are relatively inexpensive, which is why manufacturing costs are reduced. 
     Particularly preferably, the first layer is applied at a distance of less than 500 μm and preferably of less than 100 μm, and suitably at a distance of less than 50 μm to the bottom side of the first shield, wherein, for example, the distance is greater than 10 μm or 20 μm. Particularly preferably, the first layer is attached without a gap to the bottom side of the first shield. For example, the first layer is electrically contacted with the first shield. Due to the relatively small distance, the propagation of eddy currents within the first layer is improved, wherein the magnetic field lines run predominantly in the first shield. For example, the first layer is glued or vapor-deposited onto the first shield. Manufacture is further simplified in this way. Alternatively, the first layer is materially connected to the first shield, for example, by gluing or by metallization. 
     The thickness of the first layer is preferably between 5 μm and 0.7 mm, in particular between 15 μm and 150 μm, advantageously between 30 μm and 100 μm, or between 0.05 mm and 0.7 mm, wherein the thickness is expediently determined perpendicular to the main propagation direction and/or perpendicular to the plane within which the first layer is arranged. In particular, the direction in which the thickness is determined is parallel to the direction in which a thickness of the first shield is determined, and/or parallel to the longitudinal direction. Particularly preferably, the thickness is between 0.1 mm and 0.3 mm and, for example, substantially equal to 0.2 mm, wherein there is in particular a deviation of 10%, 5%, 2%, or 0%. Particularly preferably, the first layer is designed sheet-like and expediently is a foil. For example, the first layer is made elastically bendable and flexible. Due to the relatively small dimensions, the space requirement is low, which is why installation of the antenna is simplified. Particularly preferably, the first layer is made of a diamagnetic copper foil or a paramagnetic aluminum foil. 
     In particular, the first layer is used for electromagnetic radio communication. In other words, the antenna has two antenna systems, wherein one (first antenna system) is formed at least partially by the turns. The remaining antenna system (second antenna system) is at least partially formed by the first layer. The frequency range of the second antenna system in this case is expediently between 800 MHz and 50 GHz and, for example, between 1 GHz and 30 GHz. The length of the first layer with respect to the wavelength selected for radio communication, therefore, for example, 3 GHz, preferably has a length of λ/4, therefore, substantially between 2 and 2.5 cm. Suitably, in this case the length of the first shield is substantially at least equally great. By means of the first layer, a so-called patch antenna is in particular partially formed, therefore, in particular a planar monopole. 
     For example, the length of the coil core in the longitudinal direction is between 2.0 mm and 8.0 mm, preferably between 3.0 mm and 7.0 mm, and particularly preferably between 3.5 mm and 5.5 mm. In this way, a relatively compact antenna is created, which can also be placed in a hearing device. In this case, the longitudinal direction is, for example, perpendicular or substantially perpendicular to a viewing direction of the hearing device wearer. For example, the coil core is made hollow. In other words, the coil core is hollow cylindrical, wherein the hollow extends substantially in the longitudinal direction. Particularly preferably, the coil core is made of a soft magnetic material, such as, for example, a soft magnetic ferrite, and preferably is formed thereof. In particular, the coil core has a chamfer, which expediently extends in the longitudinal direction. Due to the chamfer, it is possible to influence a coupling of magnetic field lines in the coil core and thus to determine a preferred direction of the antenna. 
     Suitably, the coil core is cylindrical, wherein a cross section of the coil core perpendicular to the longitudinal direction is round, for example. In particular, the cross section is completely or partially filled by the coil core, so that either a hollow cylindrical or a solid cylindrical coil core is provided. The diameter of the circle is, for example, between 0.05 mm and 3.0 mm and suitably between 0.5 mm and 2.5 mm. For example, the diameter is between 1.0 mm and 1.5 mm. Due to the round cross section, damage to the turns during assembly is substantially excluded, wherein due to the diameter a relatively compact coil core is provided, which is why a space requirement is reduced. In addition, because of the small diameter, the ratio of the length of the antenna to the diameter is relatively large, which is why a quality of the antenna at a given antenna volume is improved. 
     In an alternative, the coil core has a rectangular cross section perpendicular to the longitudinal direction, and the coil core is thus configured substantially cuboid. In this case, one side of the cross section expediently has a length between 0.05 mm and 3.0 mm, for example, between 0.05 mm and 2.5 mm, in particular between 0.1 mm and 2.0 mm, and preferably between 0.3 mm and 1.5 mm. In particular, the height of the cuboid coil core is thus between 0.3 mm and 1.5 mm. Alternatively or in combination therewith, the other side has a length between 0.3 mm and 8.0 mm, in particular between 0.5 mm and 6.0 mm, and preferably between 1.0 mm and 5.0 mm. In other words, the width of the cuboid coil core is between 1.0 mm and 5.0 mm. 
     Particularly preferably, the antenna has a second shield, which is designed planar and is preferably made of a ferrimagnetic and/or ferromagnetic material. The second shield is arranged on the coil core end face facing away from the first shield, and the second shield extends at an angle to the longitudinal direction of the coil core. The second shield is designed planar and thus preferably extends substantially in a plane or has only relatively small deviations from the plane. However, at least the extent of the second shield in one, preferably two spatial directions is greater than in a third spatial direction, wherein the spatial directions are arranged perpendicular to each other. In particular, in this case, the extent is two times, five times, ten times, or twenty times greater. Preferably, the projection of the end face in the longitudinal direction is at least partially, preferably completely covered by the second shield. Due to the second shield, the transmission quality and reception quality of the antenna are improved. 
     For example, the second shield is structurally identical and/or symmetric to the first shield, wherein the plane of symmetry runs expediently perpendicular to the longitudinal direction between the two shields. Particularly preferably, the second shield is made of the same material as the first shield. In particular, the angle which the second shield encloses relative to the longitudinal direction is equal to the angle of the first shield, wherein a U-shape is preferably formed by the two shields and the coil core. However, the two shields are arranged at least in a V-shape to each other and are expediently not parallel, provided that at least one of the shields is not arranged perpendicular to the longitudinal direction. Suitably, the first shield and the second shield extend wing-like along the same spatial direction, starting from the respective end face of the coil core. For example, the second shield is mortised with the coil core and expediently adjoins the coil core without a gap. The thickness of the second shield is preferably between 0.05 mm and 0.7 mm and the permeability is expediently greater than 5, wherein the electrical conductivity is less than 10 6  S/m. In particular, the second shield is designed like a foil and is in particular a foil. 
     A second layer made of a material having a magnetic permeability of less than 1000 can also be arranged at least partially on the bottom side of the second shield, said side facing the coil core. In particular, the conductivity of the material of the second layer is greater than 10 6  S/m. The second layer is preferably attached without a gap on the bottom side of the second shield and/or is preferably a foil. Expediently, the second layer is substantially structurally identical to the first layer and is suitably made of the same material as the first layer. Preferably, the arrangement of the second layer with respect to the second shield is substantially a mirror image of the arrangement of the first layer with respect to the first shield, wherein the plane of symmetry runs expediently perpendicular to the longitudinal direction between the two shields. In other words, the second layer is arranged symmetrically to the first layer with respect to a mirror plane running perpendicular to the longitudinal axis. Thus, a shielded spatial region is created between the two shields by the two layers, so that any electrical and/or electronic components positioned there and electrical conductors are not disturbed or disturbed only relatively slightly due to a magnetic field of the antenna. Also, such components have a relatively low interfering effect on the antenna, which is why a signal-to-noise ratio is increased. 
     The first layer and the second layer can be electrically connected to one another, for example, by means of a preferably planar shorting bar. Suitably, the connection is located outside the turns. Expediently, a second antenna system is formed by the two layers and the connection, or the second antenna system comprises at least the two electrically interconnected layers. These are preferably used for electromagnetic radio communication. The frequency range is expediently in each case between 800 MHz and 50 GHz, preferably between 1 GHz and 6 GHz, and in particular substantially between 2 GHz and 4 GHz, and is, for example, 2.4 GHz or 3.2 GHz. Suitably, the or each shield or the or each layer has a length of λ/4, based on a wavelength λ selected for each radio communication, taking into account material quantities, in particular the permittivity c and/or the permeability μ. 
     The antenna in the region of the coil core can comprise a base point for the (electrical) connection to ground, in particular to the device ground, provided that the antenna is used in a hearing device. Suitably, an electrical conductor, by means of which the two layers are electrically contacted with each other (shorting bar), is electrically connected to the base point or forms the base point. As a result, it is possible to adjust a resonance of the antenna formed by the two shields and thus to adjust the efficiency of the second antenna system. 
     The first shield and the coil core can be formed as a continuous foil structure. For example, the first shield and the coil core are made of two foils that are joined together. Particularly preferably, however, the first shield and the coil core are made of a single foil and are thus integral with each other. Expediently, the angling of the first shield relative to the coil core is realized by means of folding. In other words, the foil structure is folded. For example, the antenna has the second shield, which is also part of the foil structure, and thus associated with the first shield and the coil core. The foil structure is, for example, a single-layer or multilayer foil, wherein at least one of the layers expediently comprises a ferrimagnetic and/or ferromagnetic material, in particular a metallic ferrite, and preferably is formed thereof. For example, this layer is applied to a carrier material or the carrier material is formed by the ferrimagnetic or ferromagnetic material. The foil structure expediently has an electrically conductive region. 
     The antenna in the region of the turns can have a printed circuit board, which is connected to the coil core, for example, attached thereto. In this case, the turns surround the circuit board and the foil structure on the periphery, so that the turns wind at least partially around the circuit board. The coil core is stabilized due to the circuit board; this simplifies winding and thus attaching of the turns. The circuit board is, for example, a glass fiber-reinforced epoxy resin or a reinforced paper. Particularly preferably, the circuit board comprises an electrical terminal, in particular two electrical terminals, wherein at least one of the turns, expediently two of the turns, are electrically (directly) contacted with the electrical terminals, for example, by means of bonding. In this way, energization and/or tapping of an electrical voltage at the turns are simplified and contact with electronics is simplified. In summary, a circuit board, which (jointly) carries the turns and which carries the electrical terminals connected to the turns, is arranged in the region of the coil core. 
     The foil structure, for example, in the region of the coil core, can have at least partially a first layer, a second layer, and a third layer. In other words, the foil structure is formed with at least three layers. The three layers are stacked on top of each other and expediently fixed together, for example, by means of lamination. Alternatively, the layers are applied by means of coating, for example, to one of the layers or another carrier structure. Here, the second layer is arranged between the first layer and the third layer. The coil core is at least partially formed by the second layer. In particular, the second layer is made of a soft magnetic (permeable) material, in particular a soft magnetic ferrite, or at least comprises it. The turns are preferably formed by the first layer and the third layer. In this case, the first layer and the third layer particularly preferably have traces which are interconnected by means of vias. Preferably, the foil structure comprises one, preferably two auxiliary layers, which are arranged adjacent to the second layer between the first layer and the third layer, and surround the second layer, for example, at the edge. The via expediently runs in the auxiliary layers. Thus, the second layer is substantially completely surrounded, so that damage is prevented. For example, the foil structure is designed in three layers only in the region of the coil core. Particularly preferably, the foil structure is designed completely in three layers, so that the foil structure can be separated out of a bulk or sheet product without relatively large lamination processes or the like being subsequently necessary. 
     The method for manufacturing the antenna provides that in a first step, a foil-like sheet or bulk product is provided. The sheet or bulk product is formed like a foil and has, for example, one or more layers. In particular, at least one of the layers or the entire sheet or bulk product is made of a ferrimagnetic and/or ferromagnetic material. In a further step, the foil structure is separated from the sheet or bulk product. For example, the foil structure is punched or cut from the sheet or bulk product, for example, by means of laser cutting or a cutter. The foil structure is designed in particular substantially L-shaped or U-shaped, wherein the two mutually parallel legs will form the two shields of the antenna, and the middle part expediently at least partially the coil core. For example, the turns are subsequently applied to the foil structure, in particular in the region which will form the coil core. In particular, the turns are also applied in the region which will form at least part of one of the shields, preferably each shield. Suitably, the circuit board is first attached to the foil structure. Alternatively, for example, plating through takes place between two of the layers of the foil structure to form the turns. In a further step, the first shield, in particular the second shield as well, if present, are angled with respect to the longitudinal direction of the coil core. In other words, the foil structure is angled, in particular bent, so that the first shield and the coil core or the second shield are provided. For example, a fold is introduced into the foil structure to form the first shield and the coil core. 
     For example, the hearing device can be an earphone or comprises an earphone. However, the hearing device is particularly preferably a hearing aid. The hearing aid is used to assist a person suffering from a reduction in hearing ability. In other words, the hearing aid is a medical device by means of which, for example, partial hearing loss is compensated. The hearing aid is, for example, a “receiver-in-the-canal” hearing aid (RIC), an in-the-ear hearing aid, an “in-the-canal” hearing aid (ITC), or a “completely-in-canal” hearing aid (CIC), hearing aid glasses, a pocket hearing aid, a bone conduction hearing aid, or an implant. The hearing aid is particularly preferably a behind-the-ear hearing aid, which is worn behind an auricle. 
     The hearing device comprises an antenna for wireless radio communication. The antenna has a coil core which extends along a longitudinal direction and carries a number of turns, as well as a planar first shield of a ferrimagnetic and/or ferromagnetic material, which extends at an angle to the longitudinal direction of the coil core and is arranged on an end face of the coil core. The antenna preferably has the first layer, suitably both layers, and electrical and/or electronic components are arranged in an interspace between the layers of the diamagnetic or paramagnetic material; these components are in particular electromagnetically interfering components, in particular radiating traces, capacitors, and/or a digital signal processor. Consequently, an installation space is used relatively efficiently, wherein an influence on the antenna and the components is reduced due to the two layers. Suitably, the antenna is used for inductive radio communication, for which the turns are used. In this case, the frequency range is expediently between 1 kHz and 300 MHz, preferably between 100 kHz and 30 MHz. In addition, the antenna is used for electromagnetic radio communication, for which purpose the two layers are used in particular, which are preferably electrically contacted with each other by means of the shorting bar. In this case, the frequency range is expediently between 800 MHz and 50 GHz, preferably between 1 GHz and 6 GHz. 
     The antenna, in particular independently of the hearing device but particularly preferably as part of the hearing device, can be used for inductive radio communication, wherein expediently a frequency range between 1 kHz and 300 MHz, preferably between 100 kHz and 30 MHz, is employed and used at the same time for electromagnetic radio communication, wherein the frequency range here is between 800 MHz and 50 GHz, in particular between 1 GHz and 6 GHz. For example, the two radio communications are used at the same time or successively in time. In other words, data are transmitted inductively or electromagnetically by means of the antenna at the same time or subsequently in time. 
     The invention further relates to a hearing device system, which comprises, for example, two hearing devices with such an antenna, wherein the two hearing devices are at least temporarily coupled with each other by signals. In this case, the wireless radio communication is preferably used by means of which, in particular, data and/or settings are transmitted between the two hearing devices. Expediently, the data transmission takes place inductively, and the turns are preferably used for this purpose. Alternatively or in combination therewith, the hearing device system comprises a remote control, which is coupled by signals to at least one of the hearing devices or the hearing device by means of the wireless radio communication. In this case, an inductive transmission of data, such as configuration data or audio signals, expediently takes place. The hearing device system preferably comprises a smartphone or can be coupled with a smartphone by signals. Expediently, a wireless radio communication with the smartphone occurs by means of the antenna, wherein, for example, the possibly existing second antenna system is used, which suitably has at least one layer. In particular, this antenna system is substantially used to receive data, and the frequency range is expediently greater than 1 GHz. Because a relatively large frequency is used, relatively many data can be transmitted within a short time. 
     For example, the antenna can be used in addition to the inductive power transfer, so that in a certain operating mode charging of an energy storage of the hearing device is possible by means of the antenna. Suitably, the antenna thus has three operating modes, wherein the first operating mode comprises an inductive radio communication, the second operating mode the electromagnetic radio communication, and the third operating mode the inductive charging. In this case, the second operating mode is carried out, for example, simultaneously with the first operating mode and/or the third operating mode, wherein the first operating mode and the third operating mode advantageously alternate. 
     The hearing device system can be a hearing aid system. The hearing aid system is used to assist a person suffering from a reduction in hearing ability. In other words, the hearing aid system is a medical device by means of which, for example, partial hearing loss is compensated. The hearing aid system expediently comprises a behind-the-ear hearing aid worn behind an auricle, a “receiver-in-the-canal” hearing aid (RIC), an in-the-ear hearing aid, an “in-the-canal” hearing aid (ITC), or a “completely-in-canal” hearing aid (CIC), hearing aid glasses, a pocket hearing aid, a bone conduction hearing aid, or an implant. The hearing device system is in particular provided and designed to be worn on the human body. In other words, the hearing device system preferably comprises a holding device, by means of which attachment to the human body is made possible. Provided the hearing device system is a hearing aid system, at least one of the hearing devices is provided and designed to be placed, for example, behind the ear or within an auditory canal. In particular, the hearing device system is cordless and intended and designed to be inserted at least partially into an auditory canal. Particularly preferably, the hearing device system comprises an energy storage, by means of which a power supply is provided. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes, combinations, and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG. 1  shows schematically a hearing device system with two hearing devices, each comprising an antenna; 
         FIGS. 2-16  each show embodiments of the antenna; 
         FIG. 17  shows a method for manufacturing the antenna; and 
         FIG. 18  shows schematically a sheet or bulk product. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , a hearing device system  2  is shown with two structurally identical hearing aids  4 , which are provided and designed to be worn behind an ear of a user (wearer). In other words, these are in each case behind-the-ear hearing aids (behind-the-ear hearing aid), which have a sound tube (not shown), which is inserted into the ear. Each hearing aid  4  comprises a housing  6 , which is made of a plastic. A microphone  8  with two electromechanical sound transducers  10  is arranged within housing  6 . It is possible to change a directional characteristic of microphone  8  using the two electromechanical sound transducers  10  by changing a time offset between the acoustic signals detected by the respective electromechanical sound transducer  10 . The two electromechanical sound transducers  10  are coupled by signals to a signal processing unit  12  which comprises an amplifier circuit. Signal processing unit  12  is formed by circuit elements, such as electrical and/or electronic components. 
     Furthermore, a loudspeaker  14  is coupled by signals to signal processing unit  12 , said loudspeaker by means of which the audio signals picked up by microphones  8  and/or processed by signal processing unit  12  are output as sound signals. These sound signals are conducted by means of the sound tube (not shown in detail) into the ear of a user of hearing device system  2 . The energization of signal processing unit  12 , microphone  8 , and loudspeaker  14  of each hearing aid  4  is effected by means of a respective battery  16 . Each hearing aid  4  further has an antenna  18 , by means of which a wireless radio communication  20  between the two hearing aids  4  is created. Wireless radio communication  20  serves to exchange data and takes place inductively. Due to the exchange of data, it is possible to impart a spatial sense of hearing to the wearer of hearing device system  2 . In summary, hearing device system  2  is designed binaurally. 
     Further, hearing device system  2  comprises a further device  22 , which is, for example, a remote control or a smartphone. This has a communication device (not shown in detail), by means of which a further wireless radio communication  24  is created with the two antennas  18  of the two hearing devices  4 . Wireless radio communication  24  serves to exchange data between further device  22  and hearing aids  4 . In particular, in this case audio signals are transmitted, which were detected by means of further device  22 . Wireless radio communication  24  is a radio link and thus electromagnetic. In other words, a far field is used for communication. 
     In  FIG. 2 , antenna  18  is shown in greater detail in a top plan view, which is used in each of the two hearing devices  4 . Antenna  18  has a coil core  26 , which is made of a soft magnetic material or at least comprises a soft magnetic material, in particular a soft magnetic ferrite. Coil core  26  is made cylindrical and extends along a longitudinal axis  28 . Thus, coil core  26  has a first end face  30  and a second end face  32 , which delimit coil core  26  in a longitudinal direction  34  that is parallel to longitudinal axis  28 . The extent of coil core  26  in longitudinal direction  34  is between 4 mm and 6 mm and equal to 5 mm. Coil core  26  carries a number of turns  36  which form a coil, wherein the coil is located substantially in the center on coil core  26 , so that the two end faces  30 ,  32  are distanced in the longitudinal direction  34  from the coil core. Turns  36  are formed next to each other and the coil is made as a single piece. The coil is made of a coated enameled copper wire and comprises between 50 and 70 such turns  36 , which are wound around coil core  26 . 
     A first shield  38  is placed flush on first end face  30 , wherein first end face  30  is completely covered by first shield  38 . In this case, first shield  38  adjoins coil core  26  without a gap. First shield  38  is materially connected, in particular glued, to coil core  26 . In other words, first shield  38  adjoins coil core  26  without a gap. First shield  38  is made of a foil and has a planar design. In other words, first shield  38  extends substantially in one plane. The plane is perpendicular to longitudinal direction  34 , so that planar first shield  38  is angled to longitudinal direction  34  of coil core  26  by an angle of 90°. The thickness of first shield  38 , therefore, its extent in longitudinal direction  34 , is substantially equal to 0.2 mm and the first shield is made of a MnZn-ferrite foil. Thus, the material of first shield  38  has an electrical conductivity of substantially 10 S/m and a magnetic permeability μ R  greater than 200. In summary, first shield  38  is made of a ferrimagnetic or ferromagnetic material. 
     A second shield  40  is placed flush on second end face  32 . In other words, the distance between first shield  38  and second shield  40  and coil  26  in each case is smaller than 300 μm. Second shield  40  is structurally identical to first shield  38  and is made of the same material. In other words, second shield  40  has the same electrical and magnetic properties as first shield  38 . Second shield  40  is arranged symmetrically with respect to first shield  38 , so that when the two shields  38 ,  40  are projected onto a mirror plane that is perpendicular to longitudinal direction  34 , the two projections overlap. Second shield  40  is thus arranged parallel to first shield  38 . In summary, second shield  40  is also made of the ferrimagnetic or ferromagnetic material and extends at an angle to longitudinal direction  34  of coil core  26 . In this case, the two shields  38 ,  40  extend wing-like from the respective end  30 ,  32  along each spatial direction. 
     At bottom side  42  of first shield  38 , said bottom side facing coil core  26 , a first layer  44  is connected, in particular fixed and preferably glued, to first shield  38  without a gap. In other words, first layer  44  is arranged at a distance of less than 500 μm to first shield  38 . First layer  44  also has a planar design and covers bottom side  42  of first shield  38  in a region which is spaced apart from coil core  26 . Here, first layer  44  is applied flat to first shield  38  and has a thickness, therefore, an extent in longitudinal direction  34 , of 0.05 mm. First layer  44  is made of a paramagnetic aluminum foil and thus has an electrical conductivity of 37.7·10 6  S/m, wherein the magnetic permeability is less than 2. 
     As an alternative to the aluminum foil, for example, a copper foil is used. Thus, the material of first layer  44  is a diamagnetic material. In further alternatives, first layer  44  comprises or consists of low-permeability iron, low-permeability stainless steel such as MAGNADUR 3952, cobalt, and/or nickel. However, at least the magnetic permeability of first layer  44  is less than 1000, and the electrical conductivity is greater than 10 6  S/m, and the material is either paramagnetic or diamagnetic. 
     Antenna  18  further has a second layer  46  made of the same material as first layer  44  and thus having the same magnetic and electrical properties. Also, second layer  46  is made of the same foil as first layer  44  and connected to second shield  40  in the same manner as first layer  44 . Second layer  46  is thus fixed to bottom side  47  facing coil core  26  and first shield  38 . 
     Second layer  46  is arranged relative to first layer  44  symmetrically with respect to a mirror plane, which is arranged perpendicular to longitudinal direction  34 . In other words, the two layers  44 ,  46  face each other. First layer  44  and second layer  46  are electrically contacted by a shorting bar  48  which extends along bottom side  42  of first shield  38  and bottom side  47  of second shield  40  and along coil core  26  in the region free of turns  36 . Planar shorting bar  48  spans turns  36  on the outside, which is why it does not run inside the coil formed by turns  36 . 
     A first antenna system, which is used for producing the inductive wireless radio communication  20 , is formed by coil core  26 , turns  36 , and first shield  38  and second shield  40 . In this case, turns  36  are suitably supplied with an alternating current, so that magnetic field lines  50  form, only two of which are shown by way of example. These are formed by the two shields  38 ,  40 . 
     An interspace  52 , in which the number of magnetic field lines  50  is reduced due to the material of the two layers  44 ,  46 , is formed between the two layers  44 ,  46 . A further component  54  or further components, which interfere electromagnetically, in particular traces, a capacitor, or a digital signal processor, are arranged in interspace  52 . In a variant, a part of signal processing unit  12  is located in interspace  52 . In other words, further component  54  is part of signal processing unit  12 . Magnetic field lines  50  are drawn into the two shields  38 ,  40  due to the material of the two layers  44 ,  46 , which increases the transmission quality or reception quality of antenna  18 . However, any eddy currents are predominantly formed within layers  44 ,  46 , and the two shields  38 ,  40  are substantially free of eddy currents, which results in a reduced power requirement and an increased figure of merit if a further component  54  is present. 
     A second antenna system, which is used for electromagnetic wireless radio communication  24 , is provided by the two layers  44 ,  46  and shorting bar  48 . In this case, both radio communications  20 ,  24  can be operated at the same time. In inductive wireless radio communication  20 , the selected frequency range is between 100 kHz and 30 MHz, and the frequency range between 1 GHz and 6 GHz is used in electromagnetic wireless radio communication  24 . In a further operating mode, antenna  18  and in particular turns  36  and coil core  26  are used for inductive power transfer and thus for charging battery  16 . 
     A variation of antenna  18  is shown in  FIG. 3 , wherein, for example, the two layers  44 ,  46  are omitted. However, these are present in a further alternative, as is shorting bar  48  and further component  54 . First shield  38  is angled with respect to longitudinal direction  34  at an angle of 80°, and second shield  40  as well is also angled at an angle of 80°, wherein the two shields  38 ,  40  are not parallel to each other and therefore enclose an angle of 20° to each other. Thus, the extent of antenna  18  in longitudinal direction  34  is increased, so that a quality of antenna  18  is further improved. 
     In  FIG. 4 , antenna  18  is shown in perspective in a further embodiment. 
     First shield  38  and second shield  40  are again arranged parallel to each other and perpendicular to longitudinal direction  34  of coil body  26 , which carries an increased number of turns  36 . In addition, first shield  38  and second shield  40  have a circular cross section perpendicular to longitudinal direction  34 , and coil core  26  as well has a circular cross section perpendicular to longitudinal direction  34 . Coil core  26  has a diameter between 1.0 and 1.5 mm, and coil core  26  is arranged concentric with the two shields  38 ,  40 . In other words, the centers of circular shields  38 ,  40  lie on longitudinal axis  28 , with respect to which coil core  26  is rotationally symmetric. Coil core  26  is hollow in a further alternative. The two layers  44 ,  46  are not shown but are present in a further alternative. Here, the two layers  44 ,  46  are annular and radially slotted, so that they are not rotationally symmetric with respect to longitudinal direction  34 . This avoids excessive formation of eddy currents in the respective layers  44 ,  46 , which would otherwise lead to a deterioration in quality. Also, the length of coil core  26  in longitudinal direction  34  is between 2 mm and 8 mm and, for example, equal to 5 mm. 
     A further embodiment of antenna  18  is shown in  FIG. 5 . As a variation to the embodiment shown in  FIG. 4 , the cross section of the mutually parallel shields  38 ,  40  perpendicular to longitudinal direction  34  is rectangular or square. The cross section of coil core  26  as well is rectangular, and coil core  26  thus has cuboid form. The extent of the coil core in longitudinal direction  34  in the illustrated example is equal to 4 mm, and one side of the rectangular cross section has a length between 0.05 mm and 3.0 mm or between 0.05 mm and 2.5 mm and the other side has a length between 0.3 mm and 8 mm. In particular, the lengths here are between 0.3 mm and 1.5 mm or between 1 mm and 5 mm. 
     A further embodiment of antenna  18  is shown in  FIG. 6 , wherein the two shields  38 ,  40  are substantially elliptic. The two shields  38 ,  40  project over coil body  26  perpendicular to longitudinal direction  34  in each direction, and each bottom side  42 ,  47 , with the exception of the direct contact with coil body  26  and the substantially radially extending slot, is provided in each case with layer  44 ,  46 . As a result, an interspace  52  is formed which substantially surrounds coil body  26  and in which a plurality of further components  54  are arranged. Here, further components  54  include the two electromechanical sound transducers  10  as well as parts of signal processing unit  12 . In addition, coil body  26  has a chamfer extending in longitudinal direction  34  and not shown in detail, within which an edge of a printed circuit board of signal processing unit  12  is arranged; this makes efficient use of the installation space. Antenna  18  is also stabilized in this way. 
     A further embodiment of antenna  18  is shown in  FIGS. 7 and 8  in each case in perspective. Coil core  26  is pentagonal in shape, and the first and second shields  38 ,  40  have an irregular shape. The two shields  38 ,  40  are parallel to each other and symmetric with respect to a plane of symmetry that is perpendicular to longitudinal direction  34 . Furthermore, the antenna comprises two terminals  56  which are each electrically contacted with one of turns  36 . Terminals  56  are copper strips and are used for the electrical contacting of antenna  18  with signal processing unit  12 . 
     In  FIG. 9 , an embodiment of antenna  18  is shown in part in a sectional view along longitudinal axis  28 . First shield  38  is placed flush on coil core  26 , wherein the distance in longitudinal direction  34  is less than 300 μm. First shield  38 , however, is spaced from coil core  26 , for example, in particular due to an adhesive layer. In the shown example, first shield  38  is fabricated of low-permeability iron. However, a low-permeability stainless steel or another ferromagnetic or ferrimagnetic material can also be used. In addition, it is possible that second shield  40  and the two layers  44 ,  46  are present, which, however, are not shown, any more than turns  36 . 
       FIG. 10  shows a variation of antenna  18  shown as a partial view in  FIG. 9 . First shield  38  has a recess  58  in which coil core  26  is inserted to form a clearance fit. End face  30  is flush with the surface of first shield  38 , said surface facing away from bottom side  42 . In other words, first shield  38  is mortised with end face  30  of coil core  26 . 
     A further variation of antenna  18 , shown in  FIG. 10 , is shown in  FIG. 11 . Recess  58 , which is concentric to longitudinal axis  28 , is designed reduced in size, and coil core  26  has a tenon  60 , which is reduced in cross section, at the end, facing end face  30 , in longitudinal direction  34 . The cross section of tenon  60  perpendicular to longitudinal direction  34  is reduced in comparison with the cross section of coil core  26 , which is spaced from first shield  38 . In other words, coil core  26  is designed step-shaped in the region of end face  30 . The cross section of tenon  60  corresponds to recess  58 , and the extent of tenon  60  in longitudinal direction  34  is equal to the thickness of first shield  38 , so that coil core  26  is set relatively stably on first shield  38 . 
       FIG. 12  shows a further embodiment of antenna  18  perspectively in a top plan view and in  FIG. 13  in a bottom view. Antenna  18  has a foil structure  62 , by means of which coil core  26  and first shield  38  and second shield  40  are formed. Foil structure  62  made of a ferrite is designed as a single layer and is substantially made in a U-shape, into which two folds  64  are introduced, so that the two shields  38 ,  40  extend at an angle to longitudinal direction  34 . In a further alternative, first shield  38  and coil core  26  are each provided with a separate foil, which were mechanically separated from each other, however, and joined together. A printed circuit board  66 , which is made of a glass fiber-reinforced epoxy resin, is connected to coil core  26  in the region of turns  36 . Circuit board  66  is configured U-shaped and arranged spaced between the two shields  38 ,  40 . The free ends of the U-shaped circuit board  66  project into interspace  52 , and turns  36  surround the middle leg of circuit board  66 . Circuit board  66  has terminals  56 , which are contacted electrically by traces  68  with the coil formed by turns  36 . Circuit board  66  is glued in particular to foil structure  62 . 
     The two layers  44 ,  46  are electrically contacted to each other by shorting bar  58 , which is likewise fastened to circuit board  66  and guided peripherally around turns  36 , so that shorting bar  58  runs outside the coil formed by turns  36 . Due to circuit board  66 , coil core  26  is stabilized in the region of turns  36 . In other words, coil core  26  is not pliable in the region, which is why attaching turns  36  is simplified. In addition, the position of turns  36  is stabilized due to the U-shape of circuit board  66 , which is spaced from the two shields  38 ,  40 . 
     In  FIG. 14 , one of the hearing devices  4  is shown perspectively without housing  6  with a further embodiment of antenna  18  in a partial view, wherein it is also comprised of foil structure  62 . The two shields  38 ,  40  are made wing-like and slightly curved, but nevertheless planar. In  FIG. 15 , the embodiment of the antenna is shown in a further perspective. Antenna  18  has a ground connection  70 , which is electrically contacted with coil core  26  or shorting bar  48 . By means of ground connection  70 , coil core  26  or shorting bar  48  is electrically taken to a device ground of hearing device  4 . Thus, the impedance can be adjusted, which is why a resonant circuit formed by antenna  18  can be set to a specific resonant frequency. Ground connection  70  is electrically contacted with signal processing unit  12  via which the device ground is provided. 
       FIG. 16  shows a further embodiment of antenna  18 , wherein only coil core  26  is shown in a sectional view perpendicular to longitudinal direction  34 . Coil core  26  and the two shields  38 ,  40  are formed as the continuous foil structure  62 , which is, however, designed as three layers. Foil structure  62  thus has a first layer  72 , a second layer  74 , and a third layer  76 , which are designed substantially planar and stacked one above the other, wherein second layer  74  is arranged between first layer  72  and third layer  76 . First layer  72  and third layer  76  are congruent, whereas second layer  74  is made smaller and is spaced from an edge region of foil structure  62 . The edge region is formed by two auxiliary layers  78 , which are likewise arranged between first layer  72  and third layer  76 . The composite of second layer  74  and auxiliary layers  78  is congruent with first layer  72  and third layer  76 . Thus, second layer  74  is completely shielded from the environment. First layer  72 , second layer  74 , third layer  76 , and auxiliary layers  78  are fastened to one another by means of lamination. 
     Second layer  74  is made of a soft magnetic ferrite and forms coil core  26 . First layer  72  has traces  80  which are electrically insulated from each other and which are applied to an electrically insulating carrier of first layer  72 , and which are spaced from second layer  74 . Traces  80  of first layer  72  extend transversely to longitudinal direction  34  and are substantially rectilinear. Each trace  80  of first layer  72  is electrically contacted at its end by vias  82 , only one of which is shown and which passes through auxiliary layers  78 , with traces of third layer  76 , which are perpendicular or also transverse to longitudinal direction  34  but are inclined in the opposite direction to traces  80  of first layer  72 . Turns  36  are created by means of traces  80  of first layer  72  and the traces of third layer  76  and vias  82 , and antenna  18  is also designed to be flexible in the region of coil core  26 . One of the terminals  56  is also at least partially formed by means of at least one of the traces. In a further alternative, first shield  38  and coil core  26  are provided by means of a foil, but are mechanically separated from each other. 
     A method  84  for manufacturing antenna  18  having foil structure  62  is shown in  FIG. 17 . In a first step  86 , a foil-like sheet or bulk product  88  is provided, which is shown by way of example in  FIG. 18 . The dimension of the sheet is, for example, greater than 30 cm by 30 cm, or the bulk product has a width of at least 10 cm and, for example, a length of over 1 m. Sheet or bulk product  88  is formed by a foil. In other words, the foil is available as a sheet or bulk product  88 . Sheet or bulk product  88  is designed either single-layered or multi-layered, for example, three-layered, wherein this is provided depending on the embodiment of the antenna. Thus, for example, the sheet or bulk product is made in three layers for antenna  18  shown in  FIG. 16 . 
     In a second step  90 , foil structure  62  is cut out of sheet or bulk product  88  by means of punching. Following this, for example, circuit board  66  is attached to the sheet-like foil structure  62  or vias  82  are created. In particular, in second step  90 , turns  36  are created, wherein these are suitably electrically contacted with terminals  56 . In a subsequent third step  92 , first shield  38  and second shield  40 , which are each formed by means of the two mutually parallel legs of the U-shaped foil structure  62 , are angled with respect to coil core  26 , which is formed by means of the connecting leg. Thus, the two shields  38 ,  40  are angled to longitudinal direction  34  of coil core  28 . For this purpose, for example, folds  64  are introduced into foil structure  62 . 
     The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived herefrom by the skilled artisan, without going beyond the subject of the invention. Particularly, further all individual features described in relation to the individual exemplary embodiments can also be combined with one another in a different manner, without going beyond the subject of the invention. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims