EP1978592A1 - Dispositif d'identification à distance et antenne de système d'identification à distance - Google Patents

Dispositif d'identification à distance et antenne de système d'identification à distance Download PDF

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Publication number
EP1978592A1
EP1978592A1 EP07105626A EP07105626A EP1978592A1 EP 1978592 A1 EP1978592 A1 EP 1978592A1 EP 07105626 A EP07105626 A EP 07105626A EP 07105626 A EP07105626 A EP 07105626A EP 1978592 A1 EP1978592 A1 EP 1978592A1
Authority
EP
European Patent Office
Prior art keywords
antenna
rfid
remote identifier
operating frequency
holder
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP07105626A
Other languages
German (de)
English (en)
Inventor
Heikki SEPPÄ
Kaarle Jaakkola
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valtion Teknillinen Tutkimuskeskus
Original Assignee
Valtion Teknillinen Tutkimuskeskus
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 Valtion Teknillinen Tutkimuskeskus filed Critical Valtion Teknillinen Tutkimuskeskus
Priority to EP07105626A priority Critical patent/EP1978592A1/fr
Publication of EP1978592A1 publication Critical patent/EP1978592A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • H01Q1/2225—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 active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
    • 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
    • H01Q9/06—Details
    • H01Q9/065—Microstrip dipole antennas
    • 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
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • H01Q9/28—Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines
    • H01Q9/285—Planar dipole

Definitions

  • the invention relates to a remote identifier according to Claim 1.
  • the invention also relates to an antenna structure and a method.
  • RFID remote identifiers
  • An RFID is a mark, which is remotely read using a radio signal, and which comprises an antenna, a voltage-generating circuit, radio-frequency signal modulation/demodulation circuits, logic, and memory.
  • the memory can be both written to and read from with the aid of a radio signal.
  • RFID There are several different types of RFID: passive and active, as well as those that can be connected to a reading device inductively, capacitively, or with the aid of a radio-frequency radiation field. Passive RFIDs generate the electric energy they need from the radio-frequency field aimed at them. In active RFIDs, there is a separate battery or other power source. Inductively connected RFIDs operate typically on the 100 - 125 kHz or 13.56 MHz frequencies.
  • WO publication 2006/120287 discloses one antenna solution for RFID systems, in which an electronic component, such as an RFID circuit is attached to the second surface of the antenna structure and is connected from one of its antenna terminals to the transmission line and from the other terminal to either a second transmission line or to a fold.
  • an electronic component such as an RFID circuit
  • This antenna type also is immune to the surface to which it is attached.
  • the manufacture of this type of antenna is also advantageous, as vias are not required.
  • the RFID electronics for example, can be easily combined with the antenna structure at low cost.
  • a remote identifier is a small device comprising an antenna, microcircuit, and memory, which transmits the contents of the memory by backscattering having received a send command from the reader and when the reader illuminates it with a radio signal.
  • RFID transponder In passive RFIDs, there is no battery; instead they take their operating power from the radio signal transmitted to them by the reader. The transmission of power and information between the RFID and the reader can take place with the aid of a magnetic field, electric field, or a radiating radio signal. In many RFID applications, it is important that the distance between the reader and the RFID can be long - even up to several metres.
  • a PIFA plane inverted F-antenna
  • a PIFA antenna can also be applied in connection with RFID circuits, in which the real part of the impedance of the circuit will be high, if the feed point is taken close to the open end of the antenna. In this application the RFID circuit will require a via to the ground plane of the PIFA. If, in addition to this, the antenna is slightly shorter than a quarter of the wavelength, the antenna will remain inductive and the impedance can be matched to an RFID circuit with a capacitive input impedance.
  • a problem with a PIFA antenna is that it requires a via and this increases manufacturing costs significantly. If the antenna is manufactured utilizing, for example, high-frequency circuit-board technology, the cost of the antenna can be as much as several euros.
  • An RFID antenna should be very cheap, it should have good radiation efficiency, and its directivity should be sufficient (large antenna gain). These problems are exacerbated in, for example, road-toll applications. In addition, the tuning of the antenna should not depend on the properties of the target. Furthermore, security aspects are emphasized in applications relating to payment.
  • the present invention is intended to eliminate the drawbacks of the prior art and create an entirely new type of RFID, RFID card, and antenna construction, and a method in connection with the antenna construction.
  • the invention is based on the fact that the antenna of the moveable, credit-card sized RFID card is typically functionally divided into two parts, in such a way that the RFID card by itself has a short reading distance and its antenna operates non-ideally at the operating frequency, whereas placing the RFID card in the location intended for it functionally creates an antenna with a long reading distance.
  • variable reading distance of the RFID circuit is achieved using a double-folded PAFFA antenna (Planar Asymmetrically Fed Folded Antenna, PAFFA), so that in normal operation of the RFID card the efficiency of the antenna is made low and in its operating state the antenna of the RFID card is tuned to the operating frequency with the aid of an additional antenna element at the point of use or in a holder.
  • the additional antenna element is typically a separate conductive surface (a 'ground plane').
  • the RFID according to the invention is characterized by what is stated in the characterizing portion of Claim 1.
  • the antenna construction according to the invention is, in turn, characterized by what is stated in Claim 5.
  • Advantageous areas of application include identity cards for access control, remotely readable driving licences, or road-toll cards for vehicles.
  • a road-toll card in someone's pocket cannot be read, only a card placed in a holder can be read.
  • the solution according to the invention will save system resources, because only cards that are meant to be read will be read by the system.
  • FIG 1 shows an RFID system according to the prior art, for which an antenna according to the invention is suitable.
  • Figure 2 shows a top view of an antenna according to the prior art.
  • Figure 3 shows a side view from direction A of the antenna according Figure 2 .
  • Figure 4 shows a perspective view of a second antenna according to the prior art.
  • Figure 5 shows a perspective view of one antenna according to the invention.
  • Figure 6 shows a perspective view of the antenna of Figure 5 folded and connected to a ground plane.
  • Figure 7 shows a perspective view of a second antenna according the invention.
  • Figure 8 shows a perspective view of the antenna of Figure 7 folded and connected to the vicinity of a ground plane.
  • Figure 9 shows a cross-sectional side view of one holder for the use of an RFID card.
  • Figure 10 shows a cross-sectional side view of one holder for the use of an RFID card.
  • Figure 11 shows a cross-sectional side view of a first alternative construction according to the invention.
  • Figure 12 shows a cross-sectional side view of a second alternative construction according to the invention.
  • Figure 13 shows a cross-section side view of a third alternative construction according to the invention.
  • a typical RFID system comprises a reading device 10 and an RFID 20, which have a wireless communication connection with each other.
  • the reader 10 typically comprises a processor 11, a demodulator 12, and RF electronics 13, as well as an antenna 14 for producing and receiving a radio-frequency signal.
  • the RFID 20 contains an antenna 21, a matching circuit 22, a rectifier with a detector 23, as well as a logic circuit 24 and a memory (not shown). Modulation is implemented using joint operation of the logic 24 and the matching circuit 22.
  • the RFID 20 is laminated onto a thin sheet, usually of a credit-card size.
  • One antenna according to the prior art is an antenna with a good efficiency rate and with no need for a via.
  • Figure 2 shows an antenna, in which one end of a planar transmission line 3 formed on top of an insulating layer 7 has been brought close to the 'ground plane' of the antenna.
  • the antenna becomes very small, but because the source (fold) 1 of the magnetic field and the source 2 of the electric field (the open end of the resonator) are very close to each other, the situation affects the radiation impedance and the direction of the effect.
  • the fold 1 acts as the primary source of the magnetic field. Simulations show that the antenna functions but its efficiency remains reasonably poor (20 % - 30 %).
  • the antenna is extremely small in size (about 30 mm x 30 mm when the frequency is 869 MHz and the relative permittivity of the insulator is 2.5, about 12 mm x 12 mm when the frequency is 2.45 GHz) and can be used in applications, in which a quite short distance is sufficient.
  • the RFID circuit 4 has been fitted close to the fold 1.
  • the two antenna terminals of the RFID circuit are connected between the source 1 of the magnetic field and the source 2 of the electric field of the antenna.
  • the length of the transmission line 3 is a quarter of the wavelength of the operating frequency ( ⁇ /4), or at least close to this length.
  • the RFID circuit 4 contains the electronics necessary for communication with the reader 10.
  • Figure 3 shows the antenna construction of Figure 2 , seen from the direction of arrow A.
  • the connection of the RFID circuit 4 between the source 1 of the magnetic field and the source 2 of the electric field can be seen more clearly in this figure.
  • Figure 4 shows a variation of Figures 2 and 3 , in which the RFID circuit 4 is set in the middle of an insulating base 7. On the other side of the insulating layer 7, a uniform metal plane 6 has been formed.
  • This solution has been shown to function extremely well and the application of it to an RFID circuit 4 that is capacitive but has a high impedance to its real part, results in a very small and simple structure and, on the other hand to a high efficiency. Its manufacturing technique is a little difficult, due to the double fold.
  • Figures 5 - 9 show two antennae of a slightly different type.
  • the solution according to Figures 5 - 6 brings a manufacturing-technology advantage, because an 'inlayer' type of RFID can be folded on top of a plastic structure 30, so that the part of the inlayers come on top of each other.
  • the PET membrane typically used in an inlayer does not form an insulator of the transfer line. This prevents the effect of the losses caused by the PET.
  • the arrangement leads to the second transfer line being closer to the 'ground plane' 6 beneath to the magnitude of the support membrane (usually PET) but this can easily be taken into account in dimensioning.
  • the RFID blank (the RFID card) is thus formed on a thin, for example PET, plastic membrane 30.
  • the blank is folded from the fold point 1 around the insulator piece 7, so that the blank's transfer paths 3 bend onto the opposite side of the structure relative to the RFID circuit 4.
  • the transfer lines 3 are essentially one-quarter of a wave of the operating frequency ( ⁇ /4) long, and are connected through transfer lines 31 of about the same length to the RFID circuit 4.
  • the fold 1 also acts as the primary source of the magnetic field.
  • the metal plane (6) short-circuits at the operating frequency through the fold 1, due to the transfer lines 3, in which case a virtual ground plane is formed on the upper surface of the RFID 20.
  • the antenna of the RFID 20 then tunes to the correct operating frequency and the reading distance of the RFID 20 (RFID card) increases many times.
  • an antenna is patterned on top of a relatively thick (0.5 mm - 3 mm) plastic membrane 40 and an RFID circuit 4 is attached to it, either on the surface or embedded inside the plastic 40.
  • the plastic piece 40 is folded from both sides, so that the ends do not quite touch each other underneath.
  • the metal pattern 3 under the plastic piece 40 forms a 'metal plane' 6 with the transfer line and short-circuits the fold points 1.
  • the transfer line 3 is formed like a concertina, so that space can be saved in the blank 30, in other ways the operating principle corresponds to the solution of Figures 5 and 6 .
  • the idea is to fit the vehicles permanently with a holder 32 according to Figure 9 .
  • the holder 32 can be slightly tilted relative to the corner of the windshield or window 33, in such a way that the direction of the beam of the antenna is nearly straight upwards. This is advantageous if the readers are above the road.
  • the holder 32 comprises insertion grooves 34 for the RFID card, as well as a metal plane 35 to tune the antenna of the RFID to the operating frequency.
  • Figure 10 shows a possible identity card, in which the 'metal plane' 35 is set in low-loss plastic 36 and this structure is attached to an operating holder 32 made of ABS, for example. If we use plastic, the length of the transfer line will be shorter and thus we can make a wider transfer line with lower losses. The important aspect of such a solution is that the RFID 20 can also be pressed against a plastic piece 36, so that the effective permittivity will remain constant.
  • Figures 11 - 13 outline the application of the solution according to the invention to different kinds of antenna.
  • Figure 11 shows the use of a dipole antenna in an application according to the invention, in such a way that in the operating situation the metal plane 6 tunes the RFID 20 to the operating frequency.
  • Figure 12 shows the use of a PIFA (planar inverted F-antenna) antenna in an application according to the invention, in such a way that, in the operating situation, the metal plane 6 tunes the RFID 20 to the operating frequency
  • Figure 13 shows the use of a double-folded PAFFA antenna in an application according to the invention, in such a way that, in the operating situation, the metal plane 6 tunes the RFID 20 to the operating frequency.
  • PIFA plane inverted F-antenna
  • Figures 11 - 13 show a dipole, a PIFA, and a double-folded PAFFA, as well as a metal place 6 set above them.
  • the capacitance over the antenna is increased, in which case the resonance frequency with the 'metal plane' 6 will be lower than without the ground plane.
  • the ground plane 6 will prevent losses caused by the electric field.
  • a small change (about 10 - 30 %) is obtained in the resonance frequency. This certainly prevents the reading of the RFID at the nominal frequency, but the reading of it will succeed at a lower frequency.
  • the UHF frequency is 915 and in Europe 869 MHz, so that in Europe an RFID 20 on top of a 'metal plane' 6 could easily be in tune without the 'metal plane' 6 at the USA frequency.
  • capacitance can be increased by placing the metal plane 6 very close to the antenna structure and by using plastic between the metal layers.
  • the invention discloses the idea of making an RFID in such a way that it will only operate in a suitable case. In this way it is possible to make RFIDs relating to payment and personal identification as secure as possible. In addition, in some applications the RFID is given a lossy surface, so that the metal place can also be used to eliminate the electric field. Though in this case protection is sought for various antenna solutions, to which a metal plane is connected to tune the antenna, the most important idea to be protected is to make a simple folded antenna, in which a separate metal plane is utilized, and through it the RFID is tuned when attached to a case or base.
  • the RFID can be passivated completely by placing it in a case made of a conductive material.
  • Suitable frequencies advantageous to the invention include among others 867 MHz and 2.45 GHz.
EP07105626A 2007-04-04 2007-04-04 Dispositif d'identification à distance et antenne de système d'identification à distance Withdrawn EP1978592A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP07105626A EP1978592A1 (fr) 2007-04-04 2007-04-04 Dispositif d'identification à distance et antenne de système d'identification à distance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP07105626A EP1978592A1 (fr) 2007-04-04 2007-04-04 Dispositif d'identification à distance et antenne de système d'identification à distance

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EP1978592A1 true EP1978592A1 (fr) 2008-10-08

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101075010B1 (ko) 2009-06-17 2011-10-19 전자부품연구원 Ｐｉｆａ 구조를 가지는 등방성 금속부착 태그 안테나
WO2011141633A1 (fr) * 2010-05-10 2011-11-17 Marisense Oy Étiquette d'étagère électronique sans fil
CN102683841A (zh) * 2012-06-11 2012-09-19 上海坤锐电子科技有限公司 双频通信垂直折叠手机线贴天线
CN102723595A (zh) * 2012-06-14 2012-10-10 上海坤锐电子科技有限公司 双频通信线贴天线
EP2595243A1 (fr) * 2011-11-15 2013-05-22 Alcatel Lucent Antenne à large bande
CN113296806A (zh) * 2021-05-08 2021-08-24 山东英信计算机技术有限公司 一种服务器板卡cpld烧录装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5552790A (en) * 1992-01-23 1996-09-03 Saab-Scania Combitech Aktiebolag Device for wireless transfer of information
US20010000430A1 (en) * 1999-09-02 2001-04-26 Smith Freddie W. Transponder modules, RF tagging system, method of operating a transponder module and methods of tagging an object having a conductive surface
WO2001080174A1 (fr) * 2000-04-13 2001-10-25 International Paper Antenne d'identification rf et emballage integres
US20050093700A1 (en) * 2003-10-30 2005-05-05 Battelle Memorial Institute Flat antenna architecture for use in radio frequency monitoring systems
WO2006120287A1 (fr) * 2005-05-12 2006-11-16 Valtion Teknillinen Tutkimuskeskus Structure d'antenne destinee notamment a un systeme de transpondeur rfid
EP1724714A2 (fr) * 2005-05-13 2006-11-22 NRC International Inc. Antenne Patch pour l'étiquette RFID

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5552790A (en) * 1992-01-23 1996-09-03 Saab-Scania Combitech Aktiebolag Device for wireless transfer of information
US20010000430A1 (en) * 1999-09-02 2001-04-26 Smith Freddie W. Transponder modules, RF tagging system, method of operating a transponder module and methods of tagging an object having a conductive surface
WO2001080174A1 (fr) * 2000-04-13 2001-10-25 International Paper Antenne d'identification rf et emballage integres
US20050093700A1 (en) * 2003-10-30 2005-05-05 Battelle Memorial Institute Flat antenna architecture for use in radio frequency monitoring systems
WO2006120287A1 (fr) * 2005-05-12 2006-11-16 Valtion Teknillinen Tutkimuskeskus Structure d'antenne destinee notamment a un systeme de transpondeur rfid
EP1724714A2 (fr) * 2005-05-13 2006-11-22 NRC International Inc. Antenne Patch pour l'étiquette RFID

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101075010B1 (ko) 2009-06-17 2011-10-19 전자부품연구원 Ｐｉｆａ 구조를 가지는 등방성 금속부착 태그 안테나
WO2011141633A1 (fr) * 2010-05-10 2011-11-17 Marisense Oy Étiquette d'étagère électronique sans fil
EP2595243A1 (fr) * 2011-11-15 2013-05-22 Alcatel Lucent Antenne à large bande
WO2013072023A1 (fr) * 2011-11-15 2013-05-23 Alcatel Lucent Antenne à bande large
US9287617B2 (en) 2011-11-15 2016-03-15 Alcatel Lucent Wideband antenna
CN102683841A (zh) * 2012-06-11 2012-09-19 上海坤锐电子科技有限公司 双频通信垂直折叠手机线贴天线
CN102683841B (zh) * 2012-06-11 2014-12-10 上海坤锐电子科技有限公司 双频通信垂直折叠手机线贴天线
CN102723595A (zh) * 2012-06-14 2012-10-10 上海坤锐电子科技有限公司 双频通信线贴天线
CN113296806A (zh) * 2021-05-08 2021-08-24 山东英信计算机技术有限公司 一种服务器板卡cpld烧录装置

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