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WO2008031629A1 - Microantenne pour communication en champ proche - Google Patents

Microantenne pour communication en champ proche Download PDF

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Publication number
WO2008031629A1
WO2008031629A1 PCT/EP2007/008286 EP2007008286W WO2008031629A1 WO 2008031629 A1 WO2008031629 A1 WO 2008031629A1 EP 2007008286 W EP2007008286 W EP 2007008286W WO 2008031629 A1 WO2008031629 A1 WO 2008031629A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
ghz
elements
inductive
antenna according
Prior art date
Application number
PCT/EP2007/008286
Other languages
German (de)
English (en)
Inventor
Michael Niedermayer
Ivan Ndip
Robert Hahn
Stephan Guttowski
Original Assignee
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. filed Critical Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Publication of WO2008031629A1 publication Critical patent/WO2008031629A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • H01Q1/2241—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in or for vehicle tyres
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H01Q9/0442—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular tuning means

Definitions

  • the invention relates to a microantenna for near-field communication and a communication device with such an antenna.
  • antennas for decoupling and receiving are usually realized by applying layers with good conductivity on a carrier substrate.
  • These antenna concepts are quite popular, since these antennas can be well embedded in conventional manufacturing concepts, eg as SMD antennas or embedded in printed circuit board antenna structures.
  • inductive and capacitive elements are dimensioned such that the resulting resonant antenna structure has a high sensitivity in a narrow frequency range around the resonance frequency.
  • two antenna concepts can be distinguished.
  • capacitive and inductive elements penetrate each other, for example at patch antennas.
  • the capacitive and inductive elements of the antenna structure can for the most part be constructed separately.
  • Another object of the present invention is to provide an antenna which can be manufactured to very small dimensions. Another object of the invention is to provide a communication device.
  • the invention provides an antenna for near field communication, comprising a resonant antenna structure formed from inductive and capacitive elements, wherein according to the invention, the inductive elements at least partially have a soft magnetic filling material.
  • Near field communication is to be understood here as a range of a few meters.
  • the term “filler” is intended to indicate that the soft magnetic material is at least partially in the magnetic field of the inductance.
  • a "soft magnetic” material is to be understood as meaning a material which forms only a narrow magnetization hysteresis loop, and for which ⁇ r >> 1.
  • the inductive element Due to the magnetic permeability of the soft magnetic material, the inductive element can be significantly reduced in size. Accordingly, the dimensions of the antenna are also reduced. By using a soft magnetic material, it is possible to keep the losses of the antenna small. Furthermore, the antenna is designed for near-field communication, so that a smaller radiation resistance and a lower efficiency as consequences of miniaturization remain within the reasonable range for many applications.
  • antennas in particular planar antennas, are thus possible which, for transmission frequencies of ⁇ 1 GHz, have an edge length of ⁇ 5 mm. can reach. Due to the smaller antenna volume, significantly smaller communication devices can be realized, in particular in the range of 434 MHz to 2.4 GHz. This simplifies the embedding in other objects, since various form factors are easier to implement. Since the microantennas reach a similar size as semiconductor chips, they can be stacked and contacted with other modules using similar connection technologies, for example by means of the 3D construction and connection technique, whereby extremely highly integrated, powerful, modularly constructed communication devices with additional functions such as Measurement data acquisition and data storage are possible. The smaller weight of the miniaturized antenna enables the smallest radio systems, which achieve a significantly higher robustness and therefore allow safe operation in difficult environments, for example in high-acceleration environments.
  • radio devices can be realized smaller and cheaper.
  • soft magnetic fillers By using soft magnetic fillers, a large size reduction can be achieved. Ff is reached the entire antenna by the soft-magnetic filler material an effective relative permeability ⁇ r, e, the size of the antenna by a corresponding factor to which in- verse proportion ( ⁇ r, eff) to the root of the effective permeability '/ ! proceeds, be shortened.
  • the soft magnetic fillers therefore have an essential size reduction task.
  • radio devices can be used for localization and radio communication over short distances.
  • soft magnetic materials which can be used as filling material in an antenna according to the invention are metallic materials such as iron, cobalt, nickel and their alloys and ceramic materials such as ferrites based on metal oxides such as manganese zinc or nickel zinc.
  • the soft magnetic material is arranged in a plurality, each separated by an insulator layers for suppression of electrical eddy currents.
  • a ceramic insulation such as aluminum oxide, barium titanate or aluminum nitride is suitable.
  • the soft magnetic filling material and the insulator can in particular consist of layers of a different material.
  • the insulator for the production of an antenna with primary inductive elements has a low relative dielectric constant. constant with ⁇ r ⁇ 2, preferably ⁇ r ⁇ 1.5, or the I-solator for generating an antenna with inductive and capacitive elements has a high relative dielectric constant with ⁇ > 2, preferably with ⁇ r > 5.
  • the primary inductive element variant is easier to design and adapt because the capacitance and inductance can be separately designed and manipulated (e.g., by electronic circuitry). In most cases, however, manufacturing is more complex than planar antenna concepts, where capacitive and inductive elements interpenetrate each other.
  • a further advantageous embodiment of the invention provides that for frequencies above 0.3 GHz for the magnetic permeability of the soft magnetic material ⁇ r > 1.5, preferably ⁇ r > 10, more preferably ⁇ r > 25 applies.
  • a further advantageous development of the invention provides that the capacitive elements at least in some areas have a dielectric filling material with a high dielectric constant.
  • dielectric "filler" is intended to indicate that the dielectric material is at least partially in the electric field of the capacitance.
  • Suitable filling materials are in particular micro-isolations such as aluminum oxide, aluminum nitride, silicon oxide, silicon nitride or barium titanate.
  • a further advantageous development of the invention provides that for frequencies above 0.3 GHz the relative dielectric constant of the dielectric filling material ⁇ r > 2, preferably ⁇ r > 5, applies.
  • a further advantageous embodiment of the invention provides that the antenna has a flat shape, and the top and bottom are plane-parallel to each other.
  • planar antenna is suitable, in particular, for integration in module concepts described above.
  • the shape makes it possible to simply stack the antenna, especially if the other elements also have a planar shape.
  • the outer surface of the antenna is cuboid.
  • the edge lengths are preferably ⁇ 10 mm, more preferably ⁇ 6 mm.
  • the size specifications also apply in the case of other geometric shapes, such as for a round or polygon outer surface.
  • the extent of the antenna is then preferably less than 10 mm, more preferably less than 6 mm.
  • a further advantageous embodiment of the invention provides that the antenna has at least one coil as an inductive element, and as a capacitive element has at least one plate capacitor, wherein a part of the outer surface of the coil forms at least a portion of a plate of Plattenkondensa- gate.
  • the combination of coil and plate capacitor components are used twice, the space can be further reduced thereby.
  • the inductance of the antenna is formed by exactly one coil and by exactly one plate capacitor.
  • further inductances and capacitances may be present in such an antenna structure; these must then be suitably considered in the design and the adaptation.
  • the coil has exactly one turn.
  • coil and plate capacitor are stacked as a respective planar, preferably cuboidal elements one above the other and layered a flat, preferably cuboidal shape.
  • the coil preferably has a rectangular profile.
  • the plate capacitor preferably has plane-parallel plates.
  • a further advantageous embodiment provides that the antenna is designed as a patch antenna.
  • the patch antenna includes a first and a second metal layer, which are arranged plane-parallel to each other, and between which the soft magnetic filling material, possibly also in layers separated by insulators, is arranged.
  • the plane-parallel arrangements of the first and second metal surfaces form a capacitive element.
  • the inductive element is preferably formed by the geometric shape of at least one of the two metal layers.
  • the invention provides a communication device, comprising an antenna according to one of claims 1 to 10.
  • a further advantageous development of the communication device provides that the communication device contains a circuit arrangement for tracking the resonance frequency of the antenna.
  • the communication device has a matching circuit for matching the impedance of the antenna.
  • the impedance matching due to a detuning of the antenna can be compensated via a matching circuit.
  • the reflections on the antenna structure can be measured regularly to determine the impedance.
  • the communication device has at least two antennas according to the invention, wherein the first antenna is designed for transmission with extraction of high field strength, and the second antenna is designed for receiving coupled with very low field strength.
  • the first antenna is designed for transmission with extraction of high field strength
  • the second antenna is designed for receiving coupled with very low field strength.
  • the conceptual design of the two antennas is preferably almost identical. However, since the elements of the transmitting antenna advantageously have a different (usually lower) dielectric constant or permeability with respect to the receiving antenna, this must be followed during the design (somewhat larger dimensions) or during operation (connection of additional inductors or capacitors).
  • FIG. 1 shows a first embodiment of an inventive antenna for near field communication
  • FIG. 2 shows a second embodiment of an antenna according to the invention for the Nahfeldkommuni- cation
  • FIG. 3 shows a first embodiment of a communication device according to the invention, which contains an antenna according to the invention for near field communication.
  • 1 shows a first embodiment of an inventive antenna for near field communication.
  • the antenna 1 contains a resonant antenna structure formed from inductive 2 and capacitive 3 elements, the inductive elements 2 having a soft-magnetic filling material 4 at least in regions.
  • Element a coil 2 with a turn on.
  • the capacitive element 3 has a plate capacitor 3 with two plates which are plane-parallel to one another. A part of the outer surface of the coil 2 forms a plate of the plate capacitor. 3
  • the winding of the coil and the plates of the plate capacitor are metallic.
  • the coil 2 and the plate capacitor 3 both have a rectangular profile and the shape of a planar cuboid and are stacked on top of each other, so that the overall result is a planar antenna with a cuboid, flat shape.
  • the second plate of the plate capacitor opposite the coil forms the bottom of the antenna and defines the reference potential.
  • the interior of the coil 2 is completely filled with the soft magnetic filler 4, here a ferrite.
  • the soft magnetic material 4 is divided into four equally thick layers, which are each separated by an insulator, here a silicon oxide, from each other for the suppression of e- lectric eddy currents.
  • the layers are oriented parallel to the base of the antenna.
  • the space between the two plates of the plate capacitor 3 is completely filled with a dielectric filling material 6.
  • the antenna 1 has an antenna feed 7, via which the antenna can be capacitively coupled.
  • the resonant frequency of the antenna shown here is about 868 MHz.
  • the edge length is 5 mm x 5 mm x 5 mm.
  • FIG. 2 shows a second embodiment of an inventive antenna.
  • the antenna 11 according to the second embodiment is formed as a patch antenna. It is essentially constructed in three layers with a rectangular metallic base surface 16 which defines the reference potential, an intermediate layer which has a soft magnetic material 14, and a second metal layer 17 covering the intermediate layer in regions.
  • the two metal layers 16, 17 which are plane-parallel to one another form a capacitive element 13.
  • the upper metal layer 17 essentially has a rectangular base surface, but is recessed at two adjacent corners with two square surfaces 18, leaving a web 19 in this region. By this geometry, an inductive element 12 is formed. Via the web 19, the coupling of the antenna can take place.
  • the intermediate layer between the two metal layers 16 and 17 is subdivided into six uniformly thick layers of a soft magnetic material, in this case a ferrite ceramic layer, which are each electrically separated from one another by an insulator 15, here a barium titanate.
  • the layers are oriented parallel to the metal layers 16 and 17.
  • the resonant frequency of the antenna 11 in this embodiment is about 868 MHz.
  • the dimensions are 1 mm x 1 mm x 0.3 mm.
  • Fig. 3 shows a communication device according to the invention.
  • the communication device comprises, stacked in layers, a power supply 25 as the lowermost layer, followed by a second memory 24b, a first memory 24a, a logic 23, a micro-antenna 1 according to the first embodiment, and a radio transmitter 22. All the elements mentioned have a cuboid outer surface with a uniform base, so that the stacked elements result in a cuboid block.
  • the individual elements are glued together by epoxy resin 26, which is applied in each case between adjacent elements.
  • the mechanical connection with the wireless sensor 22 is also ensured by bonding with an epoxy 26.
  • an antenna according to the second embodiment may also be used.
  • the dimensions of the communication device shown here are 6 mm x 3 mm x 6 mm. In particular, however, it is possible that the edge lengths in the range of 2 to 6 mm, depending on the application and associated structure, may vary.
  • the radio transmitter 22 has a circuit arrangement for tracking the resonance frequency of the antenna (not shown). With such a circuit arrangement, it is possible to track the resonance frequency.
  • the circuitry is based on an LUT (Look-up Table) with the stored material characteristics for various RF signal amplitudes and temperatures. Based on a temperature measurement with a temperature sensor and a field strength measurement by an RC low pass of the decoupled modulation carrier signal, a microcontroller calculates the resulting antenna inductances and capacitances and switches on a corresponding LC network.
  • LUT Look-up Table
  • the coupling of the feed line of the micro-antenna 1 is capacitive in this embodiment.
  • capacitive depending on the type of micro antenna, one inductive or in particular also a galvanic coupling possible.
  • the radio transmitter 22 has an impedance matching for the impedance matching of the antenna 1, here contain PIN diodes as switching elements. Furthermore, the radio transmitter 22 has switching elements, in this case PIN diodes, for changing the resonant frequency of the antenna 1.
  • the radio transmitter 22 For measuring the resonance frequency of the antenna 1, the radio transmitter 22 has a device which determines the resonance frequency from the DC component of the supply current in the transmission output stage.
  • the transmission output stage is capacitively coupled. Alternatively, an inductive coupling is possible.
  • the radio transmitter 22 has a low-power receiving stage with reduced sensitivity, which allows influencing of system functions via high-frequency signals.
  • the radio transmitter 22 has a rectifier for measuring the radio field strength.
  • a device is implemented in the logic 23, which makes it possible to trigger activation or synchronization of system functions via the reception of radio-frequency signals with specific identifiers, as well as system parameters for configuration.
  • the logic 23 has a second circuit arrangement for determining the spatial distances of sources of received radio-frequency signals.
  • the location determination is based on the evaluation of Field strengths with different antenna orientation. Alternatively or additionally, the location determination can also be based on the evaluation of field strengths with different carrier frequencies.
  • the communication device may have a plurality of antennas with a different orientation. This allows very specific emission characteristics and avoidance of reduced range due to polarization decoupling.
  • the communication device 21 (FIG. 3) is designed as a communication device for tire pressure measurement.
  • the structure is almost analogous to the embodiment described above.
  • the component 25 is in this case a special component with a MEMS pressure sensor with backside lithium battery, which is based on laminated lithium-manganese films and encapsulated with parylene.
  • the LUT is stored in this case on the non-volatile memory (Flash) 24a.
  • the communication device (not shown here), which in principle is constructed like the communication device 21 according to the first embodiment, has a second microantenna 1.
  • the first micro-antenna is used for transmission with extraction of higher field strength and the second micro-antenna for receiving coupled with very low field strength.
  • Radio transmitters and logic are suitably adapted to the operation of these two antennas.
  • the receiving antenna corresponds to the described second embodiment of a microphone according to the invention.
  • roantenne (see Figure 2), wherein the indication of the parameters refer to RF signal field strengths of ⁇ -40 dBm.
  • the dimensions of the transmitting antenna are about 1, 8 mm x 1.8 mm x 0.3 mm.

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  • Details Of Aerials (AREA)

Abstract

L'invention concerne une microantenne utilisée pour la communication en champ proche et un dispositif de communication. La microantenne selon l'invention utilisée pour la communication en champ proche comprend une structure d'antenne résonante composée d'éléments inductifs (2, 12) et capacitifs (3, 13). Les éléments inductifs présentent un matériau de charge (4, 14) magnétique doux, au moins par endroits. Selon l'invention, il est possible de produire des microantennes dans la plage des hautes fréquences, de dimensions très réduites, qui s'utilisent notamment comme partie d'une structure microélectronique modulaire.
PCT/EP2007/008286 2006-09-15 2007-09-13 Microantenne pour communication en champ proche WO2008031629A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102006044018.8 2006-09-15
DE102006044018A DE102006044018A1 (de) 2006-09-15 2006-09-15 Mikroantenne für Nahfeldkommunikation

Publications (1)

Publication Number Publication Date
WO2008031629A1 true WO2008031629A1 (fr) 2008-03-20

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ID=38924293

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/008286 WO2008031629A1 (fr) 2006-09-15 2007-09-13 Microantenne pour communication en champ proche

Country Status (2)

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DE (1) DE102006044018A1 (fr)
WO (1) WO2008031629A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8068011B1 (en) 2010-08-27 2011-11-29 Q Street, LLC System and method for interactive user-directed interfacing between handheld devices and RFID media
US8212735B2 (en) 2009-06-05 2012-07-03 Nokia Corporation Near field communication

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3780373A (en) * 1972-11-21 1973-12-18 Avco Corp Near field spiral antenna
EP0348636A1 (fr) * 1988-05-27 1990-01-03 Junghans Uhren Gmbh Petite antenne pour une montre commandée par radio
US6229444B1 (en) * 1997-09-12 2001-05-08 Mitsubishi Materials Corporation Theftproof tag
US20040001029A1 (en) * 2002-06-27 2004-01-01 Francis Parsche Efficient loop antenna of reduced diameter
EP1439608A1 (fr) * 2001-09-28 2004-07-21 Mitsubishi Materials Corporation Bobine antenne et etiquette d'utilisation rfid l'utilisant, antenne d'utilisation de transpondeur

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10204884A1 (de) * 2002-02-06 2003-08-14 Schreiner Gmbh & Co Kg Transponderetikett
WO2004066438A1 (fr) * 2003-01-23 2004-08-05 Vacuumschmelze Gmbh & Co. Kg Noyau d'antenne

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3780373A (en) * 1972-11-21 1973-12-18 Avco Corp Near field spiral antenna
EP0348636A1 (fr) * 1988-05-27 1990-01-03 Junghans Uhren Gmbh Petite antenne pour une montre commandée par radio
US6229444B1 (en) * 1997-09-12 2001-05-08 Mitsubishi Materials Corporation Theftproof tag
EP1439608A1 (fr) * 2001-09-28 2004-07-21 Mitsubishi Materials Corporation Bobine antenne et etiquette d'utilisation rfid l'utilisant, antenne d'utilisation de transpondeur
US20040001029A1 (en) * 2002-06-27 2004-01-01 Francis Parsche Efficient loop antenna of reduced diameter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8212735B2 (en) 2009-06-05 2012-07-03 Nokia Corporation Near field communication
US8068011B1 (en) 2010-08-27 2011-11-29 Q Street, LLC System and method for interactive user-directed interfacing between handheld devices and RFID media
US8395486B2 (en) 2010-08-27 2013-03-12 Q Street, LLC System and method for interactive user-directed interfacing between handheld devices and RFID media
US9858455B2 (en) 2010-08-27 2018-01-02 Q Street, LLC System and method for interactive user-directed interfacing between handheld devices and RFID media

Also Published As

Publication number Publication date
DE102006044018A1 (de) 2008-03-27

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