WO2004100309A2 - Appareil et procede de production d'une antenne a symetriseur integre - Google Patents

Appareil et procede de production d'une antenne a symetriseur integre Download PDF

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Publication number
WO2004100309A2
WO2004100309A2 PCT/US2004/013195 US2004013195W WO2004100309A2 WO 2004100309 A2 WO2004100309 A2 WO 2004100309A2 US 2004013195 W US2004013195 W US 2004013195W WO 2004100309 A2 WO2004100309 A2 WO 2004100309A2
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
conductor
balun
coaxial cable
microstrip
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.)
Ceased
Application number
PCT/US2004/013195
Other languages
English (en)
Other versions
WO2004100309A3 (fr
Inventor
Ronald A. Marino
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.)
WestRock MWV LLC
Original Assignee
Meadwestvaco Corp
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 Meadwestvaco Corp filed Critical Meadwestvaco Corp
Priority to EP04760622A priority Critical patent/EP1665459A4/fr
Publication of WO2004100309A2 publication Critical patent/WO2004100309A2/fr
Publication of WO2004100309A3 publication Critical patent/WO2004100309A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/04—Screened antennas
    • 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
    • H01Q1/2216—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 interrogator/reader equipment
    • 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
    • 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

Definitions

  • Radio frequency identification (RFID) systems typically use one or more reader antennae to send radio frequency (RF) signals to items tagged with RFID tags.
  • RFID tags to identify an item or person is well known in the art.
  • the RFID tags In response to the RF signals from a reader antenna, the RFID tags, when excited, produce a disturbance in the magnetic field (or electric field) that is detected by the reader antenna.
  • tags are passive tags that are excited or resonate in response to the RF signal from a reader antenna when the tags are within the detection range of the reader antenna.
  • U.S. Patent No. 6,094,173 which is incorporated by reference herein in its entirety.
  • the detection range of the RFID systems is typically limited by signal strength over short ranges, for example, frequently less than about one foot for 13.56 MHz systems. Therefore, portable reader units may be moved past a group of tagged items in order to detect all the tagged items since the tagged items are typically stored in a space significantly greater than the detection range of a stationary or fixed single reader antenna. Alternately, a large reader antenna with sufficient power and range to detect a larger number of tagged items may be used.
  • balun is a device that joins a balanced line (i.e., one that has two conductors with equal currents in opposite directions, such as a twisted pair cable) to an unbalanced line (i.e., one that has just one conductor and a ground, such as a coaxial cable).
  • a balun operates much like a transformer, in that it is used to convert an unbalanced line to a balanced line, and vice versa.
  • Applications that incorporate a balun are more likely to have improved read characteristics due to a reduction of noise as an outcome of a balanced system.
  • antenna designs that do not incorporate a DC connection to the reader may help to overcome grounding problems that may exist in a circuit.
  • FIG. 1 illustrates a conventional resonant-loop antenna system 120 having a looped conductor 100, which connects to a toroid-type balun
  • the tuning circuit 102 connects to transmission cable 103 that may connect to a device 104 (not shown) such as a transceiver, for example, an RFID reader.
  • the transmission cable 103 is typically characterized by its impedance, which in a simplified form, is approximately the square root of inductance L divided by capacitance C of the transmission cable.
  • the impedance is commonly 50 or 75 ohms.
  • the transmission cable 103, antenna loop 100, and tuning circuit 102 are connected together in a manner that most efficiently utilizes the RF power at a desired frequency, which for a given RFID system using a loop antenna, such as antenna 120, is typically a "high” frequency such as 13.56 MHz.
  • a loop antenna such as antenna 120
  • Another common “low” frequency that is often used for RFID systems is 125 kHz.
  • “Ultrahigh” (UHF) frequencies such as 900 MHz or 2.45 GHz within the RF range are also used with different antenna designs.
  • Toroid-type balun 101 is a discrete component, where the toroid coil has a ferrite core. This type of balun is typically hand wound and is a relatively expensive component. The toroid is also relatively large and the ferrite material induces a finite insertion loss. In addition, the use of the ferrite core material may make it difficult to achieve consistent results in the production of the antenna.
  • An antenna having an integral balun that, together with a transmission medium, forms a radiating structure for the antenna.
  • an antenna in the form of a resonant-loop antenna is provided for use in an RFID reader system.
  • a balun in the form of a gap or separation in a portion of a transmission medium e.g., coaxial cable, microstrip, etc.
  • FIG. 1 is an exemplary RFID antenna using a toroid-type balun
  • FIG. 2A is an antenna system with an integral balun and tuning circuit according to an embodiment of the invention.
  • FIG. 2B illustrates in greater detail the integral balun of the FIG. 2A antenna system;
  • FIGS. 3A and 3B respectively illustrate opposite sides of a printed circuit RFID antenna system incorporating an integral balun according to an embodiment of the invention.
  • An exemplary embodiment of the invention may be implemented in an RFID antenna system 200 as illustrated in FIG. 2A.
  • the exemplary antenna system 200 preferably includes a resonant-loop antenna 215 and a tuning circuit 216.
  • the loop antenna 215 is made of coaxial cable portions 201 A, 201B respectively having first and second outputs 204, 205 that may be taken from center conductors of the coaxial cable portions.
  • the tuning circuit 216 is composed of capacitors 207 and 209 that are respectively connected to coaxial cable outputs 204 and 205.
  • a bridging capacitor 208 may be connected between the terminals of capacitors 207 and 209. As shown, capacitor 207 is further connected to RF output terminal 210, and capacitor 209 is connected to ground.
  • balun 202 appears as a gap between conductive portions of coaxial cable 201 A, 201B.
  • the coaxial cable portions 201A, 201B are each made up of an outer conductor 220A, 220B and a center conductor 225, as shown in Fig. 2B.
  • the balun may appear as the gap 202 between outer conductors 220A, 220B, with the center conductor 225 remaining in electrical contact between coaxial cable portions 201 A, 201B.
  • coaxial cable 201A, 201B can be provided as a single, unitary structure laid out in a loop formation.
  • the loop formation initially contains no gaps in either its outer conductor or its center conductor.
  • a balun can be added to the loop formation preferably by removing a section of the outer conductor of the coaxial cable to create a gap in the outer conductor, while leaving the center conductor intact.
  • balun 202 can be formed from the gap between outer conductors 220A, 220B of coaxial cable portions 201A, 201B, respectively with center conductor 225 remaining intact to provide electrical conductivity between portions 201A and 201B.
  • the radiating structure of this resonant-loop antenna can be the outer conductor of the coaxial cable.
  • the antenna structure performs a dual function of a balun and a shielded transmission line path to the balun.
  • the balun allows for an equal magnitude and opposite polarity distribution across the gap in the outer conductor of the coaxial cable. This distribution is the identical distribution that the antenna structure would receive, for example, from a balanced transmission line medium. As a result, the feed does not require the radiating structure to have a return path to ground or to the RFID reader.
  • the length of coaxial cable portion 201A taken from its output 204 to the balun 202 may be optimized to enhance the tuning performance and Q of the RFID antenna system.
  • the physical distance should be taken preferably as a function of the impedance locus of the antenna loop.
  • An optimized length of coaxial cable portion 201A will position the impedance locus for optimal tuning.
  • the matching components e.g., lumped element capacitors and inductors, the susceptive properties of open or short circuited sections of transmission lines, etc.
  • the matching components must be placed at a junction along the transmission line where they will optimally match the circuit of interest.
  • An example of such a component is a "single stub" tuner.
  • the load impedance which may not perfectly match the characteristic impedance of the operating system, is rotated about a Smith chart to a point where the real part of the admittance is the inverse of the characteristic impedance of the system.
  • a Smith chart which is well-known in the art, provides a graphical procedure for solving transmission line problems, such as impedance and placement position along mismatched transmission lines.
  • the stub length is adjusted so the susceptance cancels out the susceptance of the line at the junction where the stub is placed.
  • An example of this is referenced in Liao, Samuel, Microwave Devices and Circuits. Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 1980, which is hereby incorporated by reference in its entirety.
  • the length of coaxial cable portion 201B taken from the balun 202 to output 205 may undergo the same optimization. If the second output 205 is left in an open-circuit condition, the resultant impedance of this open circuited stub is governed by the equation:
  • the impedance is governed by the equation:
  • the resultant Q of the circuit will be significantly lower and the tuning circuit will not require a resistor to lower the Q of the antenna system.
  • An optional resistive component (shown in dotted line as resistor 203 in FIG. 2A) may be used but this may make the antenna a less efficient radiator by absorbing power that would otherwise be transmitted by the antenna.
  • the resistor 203 can also be shunted across the outputs 204 and 205.
  • any antenna material or other known component(s) may be used to form an antenna structure.
  • a resonant-loop antenna 300 can be formed from a microstrip conductor, where the back plane or wider side of the microstrip acts as the radiating structure.
  • FIG. 3A illustrates a first side of the antenna, where a conductive trace 301 is formed on an insulating surface 302.
  • the conductive trace 301 in FIG. 3A is preferably not grounded.
  • a balun may be added to a selected portion of the trace 301.
  • a gap in the metallization of trace 301 may be created to form balun 310.
  • a connector 303 can couple the antenna 300 to any additional electronics or antennas that may be used.
  • FIG. 3B shows a second side of antenna 300, where a conductive trace 304 is formed in an insulating surface 302, and where the conductive trace of the first side of the antenna (shown in FIG. 3A) is shown as dotted lines in FIG. 3B.
  • conductive trace 304 follows the periphery of the microstrip surface and further connects to tuning circuit 305, which is also coupled to connector 303.
  • antenna structures 215 and 301/304 as substantially contiguous transmission lines (e.g., coaxial cable 201 (Fig. 2)) formed from a unitary structure is for illustration purposes only. Any number of segments or portions may be used to form the antenna structures, including balun 202, used when implementing the invention.

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  • Details Of Aerials (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

L'invention porte sur une antenne possédant un symétriseur intégré qui forme, avec un support de transmission, une structure de rayonnement pour l'antenne. Selon une forme d'exécution de cette invention, l'antenne se présente sous la forme d'une antenne à circuit résonant destinée à être utilisée dans un système de lecteur d'identification par radio-fréquence. Un symétriseur intégré à l'antenne à circuit résonant se présente sous la forme d'un intervalle ou séparation dans une partie d'un support de transmission (tel qu'un câble coaxial, une microbande, etc.).
PCT/US2004/013195 2003-05-01 2004-04-29 Appareil et procede de production d'une antenne a symetriseur integre Ceased WO2004100309A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP04760622A EP1665459A4 (fr) 2003-05-01 2004-04-29 Appareil et procede de production d'une antenne a symetriseur integre

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US46672103P 2003-05-01 2003-05-01
US60/466,721 2003-05-01

Publications (2)

Publication Number Publication Date
WO2004100309A2 true WO2004100309A2 (fr) 2004-11-18
WO2004100309A3 WO2004100309A3 (fr) 2005-06-16

Family

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Family Applications (1)

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PCT/US2004/013195 Ceased WO2004100309A2 (fr) 2003-05-01 2004-04-29 Appareil et procede de production d'une antenne a symetriseur integre

Country Status (2)

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EP (1) EP1665459A4 (fr)
WO (1) WO2004100309A2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007058619A1 (fr) * 2005-11-19 2007-05-24 Agency For Science, Technology And Research Antenne de systeme d’identification par radio-frequence
FR2953620A1 (fr) * 2009-12-07 2011-06-10 Areva Nc Dispositif d'identification d'un support metallique present dans un environnement poussiereux et metallique, a encombrement reduit et application a l'identification de conteneur contenant des elements de combustible nucleaire dans leur usine de fabrication

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6951596B2 (en) 2002-01-18 2005-10-04 Avery Dennison Corporation RFID label technique
US7500307B2 (en) 2004-09-22 2009-03-10 Avery Dennison Corporation High-speed RFID circuit placement method
US7623034B2 (en) 2005-04-25 2009-11-24 Avery Dennison Corporation High-speed RFID circuit placement method and device
US7555826B2 (en) 2005-12-22 2009-07-07 Avery Dennison Corporation Method of manufacturing RFID devices

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US2423083A (en) * 1943-03-05 1947-07-01 Standard Telephones Cables Ltd Loop antenna system
JPS5226879B2 (fr) * 1972-09-19 1977-07-16
US4083006A (en) * 1973-07-10 1978-04-04 Agency Of Industrial Science & Technology Loop type standard magnetic field generator
DE3140319A1 (de) * 1981-10-10 1983-04-21 Klaus 3300 Braunschweig Münter Elektrisch abgeschirmte breitbandantenne zur phasenrichtigen erfassung der magnetischen komponente eines elektromagnetischen wechselfeldes
FR2745928B1 (fr) * 1996-03-11 2001-01-12 Gemplus Card Int Dispositif d'echange d'informations sans contact avec un ticket electronique
FR2755303A1 (fr) * 1996-10-25 1998-04-30 Gemplus Sca Antenne de champ magnetique blindee en circuit imprime
JP2001267841A (ja) * 2000-03-23 2001-09-28 Sony Corp アンテナ装置および携帯無線機
US6538614B2 (en) * 2001-04-17 2003-03-25 Lucent Technologies Inc. Broadband antenna structure

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of EP1665459A4 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007058619A1 (fr) * 2005-11-19 2007-05-24 Agency For Science, Technology And Research Antenne de systeme d’identification par radio-frequence
FR2953620A1 (fr) * 2009-12-07 2011-06-10 Areva Nc Dispositif d'identification d'un support metallique present dans un environnement poussiereux et metallique, a encombrement reduit et application a l'identification de conteneur contenant des elements de combustible nucleaire dans leur usine de fabrication
WO2011069878A1 (fr) * 2009-12-07 2011-06-16 Areva Nc Dispositif d'identification d'un support metallique present dans un environnement poussiereux et metallique, a encombrement reduit et application a l'identification de conteneur contenant des elements de combustible nucleaire dans leur usine de fabrication
CN102713943A (zh) * 2009-12-07 2012-10-03 阿海法核燃料公司 用于识别粉尘环境和金属环境中的金属衬底的整体尺寸缩小的装置和用于在相关生产工厂中识别含有核燃料元件的容器的应用方法
US9053403B2 (en) 2009-12-07 2015-06-09 Areva Nc Device having reduced overall dimensions for identifying a metal substrate in a dusty and metallic environment, and application for identifying containers containing nuclear fuel elements in the production plant thereof
CN102713943B (zh) * 2009-12-07 2015-12-02 阿海法核燃料公司 用于识别粉尘环境和金属环境中的金属衬底的整体尺寸缩小的装置和用于在相关生产工厂中识别含有核燃料元件的容器的应用方法

Also Published As

Publication number Publication date
EP1665459A2 (fr) 2006-06-07
EP1665459A4 (fr) 2006-11-22
WO2004100309A3 (fr) 2005-06-16

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