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WO2007089106A1 - Antenne à couplage de proximité entre pastille rayonnante et ligne d'amenée à extrémité courte, étiquette rfid l'utilisant, et procédé correspondant d'accord d'antenne en impédance - Google Patents

Antenne à couplage de proximité entre pastille rayonnante et ligne d'amenée à extrémité courte, étiquette rfid l'utilisant, et procédé correspondant d'accord d'antenne en impédance Download PDF

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Publication number
WO2007089106A1
WO2007089106A1 PCT/KR2007/000552 KR2007000552W WO2007089106A1 WO 2007089106 A1 WO2007089106 A1 WO 2007089106A1 KR 2007000552 W KR2007000552 W KR 2007000552W WO 2007089106 A1 WO2007089106 A1 WO 2007089106A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
radiation patch
feed line
recited
ground plate
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/KR2007/000552
Other languages
English (en)
Inventor
Hae-Won Son
Won-Kyu Choi
Gil-Young Choi
Cheol-Sig Pyo
Jong-Suk Chae
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.)
Electronics and Telecommunications Research Institute ETRI
Original Assignee
Electronics and Telecommunications Research Institute ETRI
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
Priority claimed from KR1020060129962A external-priority patent/KR100839601B1/ko
Application filed by Electronics and Telecommunications Research Institute ETRI filed Critical Electronics and Telecommunications Research Institute ETRI
Priority to US12/162,069 priority Critical patent/US20080309578A1/en
Publication of WO2007089106A1 publication Critical patent/WO2007089106A1/fr
Anticipated expiration legal-status Critical
Ceased 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
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna

Definitions

  • the present invention relates to an antenna, a radio frequency identification (RF1D) tag employing the antenna, and an antenna impedance matching method thereof; and, more particularly, to a planar antenna based on proximity coupling between a short- ended microstrip feed line and a radiation patch, an RFlD tag, or a transponder, which includes the planar antenna, and an antenna impedance matching method thereof.
  • RFID radio frequency identification
  • a radio frequency identification (RFlD) tag is used in diverse areas, such as material management and security, along with an RFlD reader, or an interrogator.
  • an RFlD reader modulates RFlD signals having a predetermined carrier frequency to thereby produce interrogation signals and transmits the interrogation signals to the RFlD tag.
  • the RFlD makes a response to the interrogation of the RFlD reader.
  • the RFlD reader modulates continuous electromagnetic waves of a predetermined frequency to thereby produce interrogation signals and transmits the interrogation signals.
  • the RFlD tag performs back-scattering modulation onto the electromagnetic waves transmitted from the RFlD reader and sends them back to the RFlD reader to deliver tag information stored in its internal memory.
  • Back-scattering modulation is a method that an RFlD tag transmits tag information by modulating the amplitude or phase of scattered electromagnetic waves, when the RFlD tag scatters the electromagnetic waves transmitted from the RFlD reader and sends them back to the RFlD reader.
  • a passive RFlD tag rectifies the electromagnetic waves transmitted from the RFlD reader and uses them as its own power source.
  • the passive RFlD tag can normally operate only when the intensity of the electromagnetic waves transmitted from the RFlD reader is equal to or higher than a predetermined threshold value at the position where the RFlD tag is disposed.
  • the read zone of the RFlD reader depends on the intensity of the electromagnetic waves transmitted from the RFlD reader and reaches the RFlD tag.
  • the transmission power of an RFlD reader is regulated by the U.S. Federal Communication Commission (FCC) and local regulations, there is limitation in raising the transmission power of an RFID reader. Therefore, the read zone needs to be widened without increasing the transmission power level of an RFID reader.
  • FCC Federal Communication Commission
  • an RFID tag includes a tag antenna, an RF front end, and a signal processor.
  • the RF front end and the signal processor are formed in one chip collectively.
  • the antenna and the RF front end are conjugate-matched through a matching circuit, which is an additional constituent element, to maximize the intensity of signals transmitted from the tag antenna to the RF front end.
  • the matching circuit composed of a capacitor and an inductor requires much space in a chip, the method using a matching circuit has a problem in the respect of miniaturization and production cost. Disclosure of Invention Technical Problem
  • an object of the present invention to provide an antenna that has wideband characteristics and can freely control the resistance and reactance of antenna impedance independently from each other by disposing a short-ended microstrip feed line that is formed in a resonance length direction of a radiation patch between the radiation patch and a ground plate and proximity-coupled with the radiation patch, and a radio frequency identification (RFID) tag employing the same.
  • RFID radio frequency identification
  • an antenna which includes: a radiation patch configured to determine a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeding part disposed between the radiation patch and the ground plate and configured to provide radio frequency (RF) signals to a device connected to the antenna.
  • RF radio frequency
  • the feeding part includes: a dielectric substrate disposed in parallel between the radiation patch and the ground plate; a feed line having a shape of a microstrip line and disposed in one surface of the dielectric substrate; and a ground surface disposed toward the ground plate in parallel to the feed line with a space therebetween.
  • One end of the feed line is close to a central part of the radiation patch connected to the ground surface, and the other end in opposite to the shorted end has a tag chip feed for accessing to the device connected to the antenna.
  • the ground surface of the feeding part is connected to the ground plate in direct current (DC) or in alternating current (AC) through capacitive coupling.
  • the ground plate disposed in parallel to the radiation patch may be used as a ground surface of the feeding part.
  • an antenna which includes: a radiation patch configured to determine a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeding part disposed between the radiation patch and the ground plate in a resonance length direction of the radiation patch and proximity-coupled with the radiation patch, and configured to provide radio frequency (RF) signals to a device connected to the antenna through a feed line having an impedance lower than 100 ⁇ in one end close to a central part of the radiation patch.
  • RF radio frequency
  • the feeding part includes: a dielectric substrate disposed in parallel between the radiation patch and the ground plate; a feed line having a shape of a microstrip line and disposed in one surface of the dielectric substrate; and a ground surface disposed toward the ground plate in parallel to the feed line with a space therebetween.
  • One end of the feed line close to the central part of the radiation patch is connected to a load having an impedance lower than 100 ⁇ , and the other end in opposite to the end connected to the load has a tag chip feed for accessing to the device connected to the antenna.
  • the load is any one between a lumped element and a distributed element.
  • an antenna which includes: a radiation patch configured to determine a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeding part disposed between the radiation patch and the ground plate and configured to provide radio frequency (RF) signals to a device connected to the antenna.
  • the feeding part includes a feed line formed in a resonance length direction of the radiation patch and having one end proximity-coupled with the ground plate.
  • the feeding part includes: a dielectric substrate disposed in parallel between the radiation patch and the ground plate; a feed line having a shape of a microstrip line and disposed in one surface of the dielectric substrate; and a ground surface disposed toward the radiation patch in parallel to the feed line with a space therebetween.
  • One end of the feed line close to a central part of the radiation patch is connected to the ground surface, and the other end in opposite to the shorted end has a tag chip feed formed therein.
  • Radio Frequency Identification (RFID) tag which includes: an antenna configured to receive RF signals transmitted from an RFID reader; an RF front end configured to rectify and detect the RF signals; and a signal processor connected to the RF front end.
  • the antenna includes: a radiation patch configured to determine a resonant frequency of the antenna; a ground plate disposed in parallel to the radiation patch; and a feeding part disposed between the radiation patch and the ground plate and configured to provide RF signals to the RF front end through a feed line which is formed in a resonance length direction of the radiation patch and proximity-coupled with the radiation patch.
  • the feeding part includes: a dielectric substrate disposed in parallel between the radiation patch and the ground plate; a feed line having a shape of a microstrip line and disposed in one surface of the dielectric substrate; and a ground surface disposed toward the ground plate in parallel to the feed line with a space therebetween.
  • One end of the feed line close to a central part of the radiation patch is connected to the ground surface, and the other end in opposite to the shorted end has a tag chip feed for accessing to the RF front end.
  • One end of the feed line close to the central part of the radiation patch may be connected to a load having an impedance lower than 100 ⁇ .
  • an impedance matching method of an antenna having a radiation patch, a ground plate disposed in parallel to the radiation patch, and a feed line disposed between the radiation patch and the ground plate in a resonance length direction of the radiation patch, comprising the steps of: a) controlling reactance of antenna input impedance by adjusting the length of the feed line; b) controlling resistance of the antenna input impedance by shifting the position of the feed line; and c) controlling reactance of the antenna input impedance by adjusting characteristic impedance of the feed line.
  • the reactance is controlled based on a property that the longer the feed line is, the higher the reactance of the antenna input impedance becomes in the reactance controlling step a).
  • the resistance is controlled based on a property that the longer the distance between the tag chip feed and the brim of the radiation patch is, the higher the resistance of the antenna input impedance in the resistance controlling step b).
  • the technology of the present invention provides an antenna that can freely control the resistance and reactance of antenna impedance independently from each other by disposing a short-ended microstrip feed line that is formed in a resonance length direction of a radiation patch between the radiation patch and a ground plate. Also, the present invention provides a plannar antenna that has a resonance characteristic and can be matched to an antenna connection element having a predetermined impedance level efficiently in wide bands by proximity-coupling the feed line with the radiation patch, and a radio frequency identification (RFlD) tag employing the antenna.
  • RFID radio frequency identification
  • the antenna based on proximity coupling with a short-ended feed line and the RFlD tag employing the antenna have resonance and wideband characteristics, and they can provide excellent performance even when they are attached to a metal surface or an object having a high dielectric rate.
  • the present invention provides a method of matching impedance of the antenna.
  • Fig. 1 is a block diagram describing a radio frequency identification (RFlD) system to which the present invention is applied;
  • RFID radio frequency identification
  • Fig. 2 is a circuit diagram modeling a tag antenna and an RF front end
  • FIG. 3 is a perspective view showing a tag antenna in accordance with a first embodiment of the present invention.
  • FIG. 4 is a perspective view showing a tag antenna in accordance with a second embodiment of the present invention.
  • FIG. 5 is a perspective view showing a tag antenna in accordance with a third embodiment of the present invention.
  • FIG. 6 is a perspective view showing a tag antenna in accordance with a fourth embodiment of the present invention.
  • Fig. 7 shows a plane view and a side view of a tag antenna to be attached to a metal object according to an embodiment of the present invention
  • Fig. 8 is a smith chart showing variance of antenna input impedance according to the varying length of the feed line of the tag antenna shown in Fig. 7;
  • Fig. 9 is a smith chart showing antenna input impedance variance according to the distance from the brim of a radiation patch to a tag chip feed in the antenna of Fig. 7; and [37] Fig. 10 is a graph showing a return loss of the antenna shown in Fig. 7.
  • Fig. 1 is a block diagram describing a radio frequency identification (RFID) system
  • the RFID system 100 includes an RFID tag 120 storing unique information, an RFID reader 110 having a reading and interpreting function, and a host computer (not shown) for processing data read from the RFID tag 120 by using the RFID reader 110.
  • the RFID reader 110 is composed of an RF transmitter 111, an RF receiver 112, and a reader antenna 113.
  • the reader antenna 113 is electrically connected to the RF transmitter 111 and the RF receiver 112.
  • the RFID reader 110 transmits RF signals to the RFID tag 120 through the RFID transmitter 111 and the reader antenna 113.
  • the RFID reader receives RF signals from the RFID tag 120 through the reader antenna 113 and the RFID receiver 112.
  • US Patent No. 4,656,463 the structure of the RFID reader 110 is widely known to those skilled in the art. Thus, detailed description on it will not be provided herein.
  • the RFID tag 120 includes an RF front end 121, a signal processor 122 and a tag antenna 123.
  • the RF front end 121 supplies power for the operation of the signal processor 122 by converting the received RF signals into direct current (DC) voltage.
  • the RF front end 121 extracts baseband signals from the received RF signals. Since the structure of the RF front end 121 is widely known to those skilled in the art of the present invention, as shown in US Patent No. 6,028,564, detailed description on the structure will not be provided herein.
  • the signal processor 122 too, may have a structure known to those skilled in the art of the present invention, and an example of it is presented in US Patent No. 5,942,987.
  • the 110 modulates RF signals having a predetermined carrier frequency and transmits an interrogation to the RFTD tag 120.
  • the 111 of the RFTD reader 110 are transmitted outside in the form of electromagnetic waves through the reader antenna 113.
  • the electromagnetic waves 130 transmitted outside are delivered to the tag antenna 123, which delivers the received electromagnetic waves 130 to the RF front end 121.
  • the RFID tag 120 performs back-scattering modulation onto the electromagnetic waves 130 transmitted from the RFTD reader 110 and responds to the interrogation of the RFID reader 110.
  • the amplitude of the electromagnetic waves 130 transmitted out of the RFTD reader 110 should be high enough to supply operation power required by the RFTD tag 120. Also, the electromagnetic waves 130 transmitted out of the RFTD reader 110 should be delivered to the RF front end 121 with almost no loss by using a highly efficient tag antenna 123. After all, the tag antenna 123 should have a resonance characteristic in the carrier frequency of the RFTD reader 110 and achieve conjugate matching with the RF front end 121 to have a high efficiency.
  • Fig. 2 is an equivalent circuit diagram modeling the tag antenna 123 and the RF front end 121.
  • the equivalent circuit is composed of a voltage source V , an antenna impedance Z , and an RF front end impedance Z .
  • the voltage source V oc and the antenna impedance Z a form an equivalent circuit of the tag antenna 123, whereas the RF front end impedance Z forms an equivalent circuit of the RF front end 121.
  • the antenna impedance Z a is composed of a real part R and an imaginary part X .
  • the real part R denotes an equivalent resistance of the tag antenna 123
  • the imaginary part X a denotes an equivalent reactance of the tag antenna 123.
  • RF front end impedance is composed of a real part R and an imaginary part X , too.
  • the real part R denotes an equivalent resistance of the RF front end 121
  • the imaginary part X denotes an equivalent reactance of the RF front end 121.
  • the maximum power is delivered from the tag antenna 123 to the RF front end 121.
  • Conjugate matching is to make the two complex impedances have the same absolute values but their phases have different signs from each other.
  • the RF front end 121 of a passive RFTD tag or a semi-passive RFTD tag is composed of a rectifying and detection circuit using a diode, and it does not include a rectifying circuit for reducing the area of a chip.
  • the RF front end 121 has complex impedances which is different from a general impedance, i.e., 50 ⁇ , and has a low resistance R c and a high capacitive reactance X c .
  • the antenna impedance Z a for conjugate matching should have low resistance R and high inductive reactance X and, at the same time, it should resonate to the frequency of electromagnetic waves transmitted out of the RFTD reader 110.
  • the tag antenna 300 includes a rectangular radiation patch 310 and a ground plate 320 disposed in parallel to the radiation patch 310.
  • the radiation patch 310 is proximity-coupled with a microstrip feed line 341.
  • the feeding part 340 of the tag antenna 300 includes a dielectric substrate 342 disposed between the radiation patch 310 and the ground plate 320, the microstrip feed line 341 disposed in one side of the dielectric substrate 342, and the ground surface 343 disposed in the other side of the dielectric substrate 342.
  • the feeding part 340 is interposed between the radiation patch 310 and the ground plate 320, and the ground surface 343 of the feeding part 340 is connected to the ground plate 320 in direct current (DC) or in alternating current (AC) through capacitive coupling.
  • the ground surface 343 connected to the ground plate 320 in alternating current can be fabricated by attaching both-sided tape onto the ground plate 320.
  • the ground plate 320 can be shared as the ground surface 343 of the feeding part 340. In this case, one metal plate is simultaneously used as the ground plate 320 and the ground surface 343.
  • the feed line 341 of the feeding part 340 is formed in a resonance length direction
  • One end of the feed line 341 is connected to the ground surface 343, while the other end has a tag chip feed 344 connected to the RF front end 121 formed therein.
  • a shorting part 345 of the feed line 341 is disposed in the central part 330 of the radiation patch 310, and the tag chip feed 344 is disposed at the brim 315 of the radiation patch 310.
  • the resonant frequency of the tag antenna 300 is mainly determined based on the length 313 of the radiation patch 310.
  • the radiation patch 310 and the ground plate 320 are disposed in parallel to each other with a predetermined space 351 between them, and the entire or part of the space between them is filled with a predetermined dielectric substance 350 including air.
  • the reactance X of the antenna impedance Z is mainly determined based on the characteristic impedance Z of the feed line 341 and the entire length 1 of the feed line
  • the resistance R of the antenna impedance Z is mainly determined based on the distance 331 from the brim 315 of the radiation patch 310 to the tag chip feed 344.
  • the distance 331 is zero, the resistance R of the antenna impedance Z becomes 0 ⁇ .
  • R a of the antenna impedance Z a based on the increase of the distance 331 is different according to the characteristics impedance Z of the feed line 341 and the size of the coupling capacitance between the feed line 341 and the radiation patch 310.
  • the distance 331 from the brim 315 of the radiation patch 310 to the tag chip feed 344 is adjusted by transferring the position of the feeding part 340 including the feed line 341 toward the center 330 of the radiation patch 310.
  • the antenna impedance Z is delicately adjusted by repeating the a second and third steps.
  • the antenna 300 of the present invention controls the reactance
  • the antenna 300 of the present invention can freely control the reactance X and the resistance R a of the antenna impedance Z a , it can be efficiently matched with the RF front end 121 having a predetermined impedance level.
  • the antenna 300 of the present invention has a wideband characteristic, just as conventional antennas using proximity- coupling feed.
  • one end of a feed line disposed close to the center of a radiation patch and the other end is stretched out of the radiation patch and has a tag chip feed formed therein.
  • An example of the conventional proximity-coupling method is disclosed in an article by D.M. Pozar entitled “Increasing the bandwidth of a microstrip antenna by proximity coupling,” Electronics Letters, Vol. 23, No. 8, April 1987.
  • the tag antenna 300 suggested in the present invention has the feed line 341, one end of which close to the center 330 of the radiation patch 310 is shorted.
  • the basic concept of the present invention can be applied if the element impedance is sufficiently low, specifically, lower than 100 ⁇ .
  • the end 345 of the feed line 341 close to the center of the radiation patch 310 has an inductive impedance lower than 100 ⁇ , there is an effect that the length of the feed line 341 can be reduced.
  • it should be considered in controlling the antenna impedance Z that the antenna impedance Z is partly affected by the impedance of an element connected to a the end 345 of the feed line 341.
  • the length 313 of the radiation patch 310 is determined such that the radiation patch 310 has a resonance characteristic in the antenna operation frequency.
  • the length 313 of the radiation patch 310 can be reduced by almost a half while maintaining the resonant frequency if a shorting plate or a series of shorting pins are set up between the radiation patch 310 and the ground plate 320.
  • Fig. 4 is a perspective view showing a tag antenna in accordance with a second embodiment of the present invention.
  • the tag antenna 400 of Fig. 4 reduces the length 413 of the radiation patch 410 by additionally including the shorting pate 430 between the radiation patch 410 and the ground plate 42 to connect the radiation patch 410 and the ground plate 420 with each other.
  • the shorting plate 430 is set up perpendicularly to a resonance length direction 41 at the brim in opposite to the tag chip feed 444 in the radiation patch 410.
  • the width 431 of the shorting plate 430 may be different from the width 414 of the radiation patch 410.
  • the input impedance of the tag antenna 400 is controlled in the same method as in Fig. 3.
  • Fig. 5 is a perspective view showing a tag antenna in accordance with a third embodiment of the present invention.
  • the tag antenna 500 reduces the length 513 of the radiation patch 510 by additionally disposing shorting pins 530 between the radiation patch 510 and the ground plate 520 to connect the radiation patch 510 with the ground plate 520.
  • the shorting pins 530 are set up perpendicularly to the resonance length direction at the brim in opposite to the tag chip feed in the radiation patch 510.
  • the input impedance of the tag antenna 500 shown in Fig. 5 is controlled in the same method as in Fig. 3.
  • the tag antenna 500 of Fig. 5 has a small feeding part 540 by forming the feed line 541 in a meander structure.
  • the feed lines 341 and 441 of the tag antennas 300 and 400 illustrated in Figs. 3 and 4 have a straight line shape.
  • the feed lines 341 and 441 may be fabricated in diverse structures widely known to those skilled in the art of the present invention, which includes the meander structure, to reduce the size of the feeding parts 340 and 440.
  • Fig. 6 is a perspective view showing a tag antenna 600 in accordance with a fourth embodiment of the present invention.
  • a ground plate 643 of a feeding part 640 may be connected to a radiation patch 610 in direct current or in alternating current through capacitive coupling.
  • the tag antenna 600 has its ground plate 620 proximity-coupled with the feed line 641.
  • the tag antenna 600 operates the same and has the same effects as the tag antennas 300, 400 and 500 shown in Figs. 3 to 5 where the ground surfaces 343, 443 and 543 of the feeding parts 340, 440 and 540 are connected to the ground plates 320, 420 and 520 in direct current, or in alternating current through capacitive coupling.
  • Fig. 7 shows a plane view and a side view of a tag antenna to be attached to a metal object according to an embodiment of the present invention.
  • the tag antenna fabricated to be attached to a metal object is conjugate-matched to a tag chip impedance Z of '7.4-j 111 [ ⁇ ]' in an RF front end 121.
  • the tag antenna to be attached to a metal object shares a ground plate 720 as a ground surface of a feeding part 740, and it includes a shorting plate 730 set up in the same width as the width of the radiation patch 710 between the radiation patch 710 and the ground plate 720 to shorten the length L 713 of the radiation patch 710.
  • One end of the feed line 741 close to the shorting plate 730 in the tag antenna 700 is connected to the ground plate 720 by shorting pins 745.
  • the other end of the feed line 741 disposed at the open brim of the radiation patch 710 has a tag chip feed 744 formed therein.
  • the tag chip feed 744 is used to access to the RF front end 121.
  • the tag antenna 700 is fabricated in the following specification.
  • the resonance direction length L 713 of the radiation patch 710 is 73mm, and the width W 714 of the radiation patch 710 is 25mm.
  • the distance H 751 between the radiation patch 710 and the ground plate 720 is 3mm.
  • the length L 747 of the dielectric substrate 746 is 40mm.
  • the width W 748 and thickness H 746 of the dielectric substrate 746 are 7mm and lmm, respectively.
  • the length 1 742 and the width W of the feed line 741 are 36mm and 3mm, respectively.
  • the distance d 731 from the brim of the radiation patch 710 to the tag chip feed 744 formed in the feed line 741 is 8mm.
  • Fig. 8 is a smith chart showing variance of antenna input impedance Z according to a the varying length 1 742 of the feed line 741 of the tag antenna shown in Fig. 7.
  • Fig. 8 As illustrated in Fig. 8, as the length 1 of the feed line 741 becomes long, the size of the imaginary part X of the antenna input impedance Z increases.
  • Fig. 9 is a diagram showing variance of the antenna input impedance Z according a to the varying distance d 731 from the brim of the radiation patch 710 to a tag chip feed 744 when the tag antenna of Fig. 7 is attached to a metal object of an infinite size.
  • the diameter of the -shaped orbital trace of the antenna input impedance Z increases.
  • the size of the real part R of the antenna input impedance Z a increases in the tag antenna of the present invention.
  • the size of the real part R of the antenna input impedance Z increases.
  • the tag antenna of the present invention can independently control the imaginary part X and the real part R of the antenna input impedance Z by controlling the length 1 of the feed line and the distance d from the brim of the radiation patch 710 to the tag chip feed 744.
  • the length L of the radiation patch 710 needs t be controlled delicately.
  • Fig. 10 is a graph showing a return loss of the antenna shown in Fig. 7.
  • the tag antenna shows wideband characteristics of 47MHz around the resonant frequency, which is 915MHz, when the return loss is 3dB. Therefore, the tag antenna of the present invention can efficiently perform wideband matching to the RF front end having a predetermined impedance.

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  • Waveguide Aerials (AREA)

Abstract

La présente invention concerne une antenne utilisant essentiellement un couplage de proximité entre, d'une part une ligne d'amenée micro-ruban à extrémité courte, et d'autre part une pastille rayonnante, l'invention concernant également une étiquette RFID comportant cette antenne plate et un procédé d'accord de l'antenne en impédance. L'antenne comporte une pastille rayonnante configurée pour déterminer une fréquence de résonance de l'antenne, une nappe de sol parallèle à la pastille rayonnante, et une amenée qui est placée entre la pastille rayonnante et la nappe de sol, et qui est configurée pour fournir des signaux radio à un dispositif relié à l'antenne. L'amenée comporte une ligne d'amenée réalisée dans le sens de la longueur de résonance de la pastille rayonnante et couplée par proximité à la pastille rayonnante, une extrémité de la ligne d'amenée étant raccourcie. L'antenne commande librement la résistance et la réactance de l'impédance d'antenne accordée indépendamment et efficacement à un dispositif connecté à l'antenne qui a une impédance prédéterminée dans les bandes larges.
PCT/KR2007/000552 2006-02-01 2007-02-01 Antenne à couplage de proximité entre pastille rayonnante et ligne d'amenée à extrémité courte, étiquette rfid l'utilisant, et procédé correspondant d'accord d'antenne en impédance Ceased WO2007089106A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/162,069 US20080309578A1 (en) 2006-02-01 2007-02-01 Antenna Using Proximity-Coupling Between Radiation Patch and Short-Ended Feed Line, Rfid Tag Employing the Same, and Antenna Impedance Matching Method Thereof

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2006-0009707 2006-02-01
KR20060009707 2006-02-01
KR10-2006-0129962 2006-12-19
KR1020060129962A KR100839601B1 (ko) 2006-02-01 2006-12-19 종단이 단락된 급전 라인과의 근접 결합을 이용한 안테나,ｒｆⅰｄ 태그 및 안테나 임피던스 정합 방법

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8164167B2 (en) 2007-03-09 2012-04-24 Nanyang Technological University Integrated circuit structure and a method of forming the same
CN107092955A (zh) * 2017-06-12 2017-08-25 北京智芯微电子科技有限公司 一种阻抗调节标签天线及电子标签
CN113866521A (zh) * 2021-11-30 2021-12-31 荣耀终端有限公司 一种天线检测装置、天线检测系统及天线检测方法
WO2023078089A1 (fr) * 2021-11-05 2023-05-11 华为技术有限公司 Dispositif électronique

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US6236314B1 (en) * 1999-09-02 2001-05-22 Micron Technology, Inc. Transponder modules, RF tagging system, method of operating a transponder module and methods of tagging an object having a conductive surface
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US8164167B2 (en) 2007-03-09 2012-04-24 Nanyang Technological University Integrated circuit structure and a method of forming the same
CN107092955A (zh) * 2017-06-12 2017-08-25 北京智芯微电子科技有限公司 一种阻抗调节标签天线及电子标签
WO2023078089A1 (fr) * 2021-11-05 2023-05-11 华为技术有限公司 Dispositif électronique
CN113866521A (zh) * 2021-11-30 2021-12-31 荣耀终端有限公司 一种天线检测装置、天线检测系统及天线检测方法

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