WO2011157883A1 - Procédé de fabrication d'une structure d'antenne à auto-compensation par gravure - Google Patents

Procédé de fabrication d'une structure d'antenne à auto-compensation par gravure Download PDF

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Publication number
WO2011157883A1
WO2011157883A1 PCT/FI2010/050516 FI2010050516W WO2011157883A1 WO 2011157883 A1 WO2011157883 A1 WO 2011157883A1 FI 2010050516 W FI2010050516 W FI 2010050516W WO 2011157883 A1 WO2011157883 A1 WO 2011157883A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna structure
tuning
antenna
etching
electrically conductive
Prior art date
Application number
PCT/FI2010/050516
Other languages
English (en)
Other versions
WO2011157883A8 (fr
Inventor
Antti Manninen
Original Assignee
Upm Raflatac Oy
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 Upm Raflatac Oy filed Critical Upm Raflatac Oy
Priority to CN201080068119.2A priority Critical patent/CN103181024B/zh
Priority to PCT/FI2010/050516 priority patent/WO2011157883A1/fr
Priority to KR1020137001201A priority patent/KR101664263B1/ko
Publication of WO2011157883A1 publication Critical patent/WO2011157883A1/fr
Publication of WO2011157883A8 publication Critical patent/WO2011157883A8/fr

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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
    • 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
    • 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
    • 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 an antenna structure comprising at least a non-conducting substrate and an electrically conductive antenna line configuration supported by the substrate, the electrically conductive antenna line configuration being fornned in an etching process by etching away locally by etchant an electrically conductive coating material supported by the substrate.
  • the invention relates to a method for manufacturing an an- tenna structure by etching, the antenna structure comprising a substrate and an electrically conductive antenna line configuration supported by the substrate, and in which method the electrically conductive antenna line configuration is formed by etching away locally by etchant an electrically conductive coating material supported by the substrate.
  • the invention relates to an etching mask for manufacturing an antenna structure by etching, the antenna structure comprising at least a non-conductive substrate and an electrically conductive antenna line configuration being formed in an etching process by etching away locally by etchant an electrically conductive coating material supported by the substrate, the etching mask determining the electrically conductive antenna line configuration of the antenna structure.
  • the invention relates to use of an antenna structure for manufacturing a radio frequency identification transponder or tag.
  • etching process variations may cause significant deviation of electrical characteristics of the electric circuits between successively etched similar etched circuits. This is especially true when etching radio frequency structures such as antenna structures.
  • radio frequency structures such as antenna structures.
  • the process variations in the etching may cause frequency behaviour variation in the etched antennas which further affects the electrical matching of the antenna with the other parts of the RFID circuitry.
  • FIG. 1 discloses a prior art radio frequency identification tag 1 or RFID tag 1 , the RFID tag 1 being one example of a product which may com- prise an antenna structure 4 comprising an electrically conductive line configuration formed by etching.
  • the RFID tag 1 comprises an antenna structure 2 comprising a substrate 3 and a dipole-like antenna 4 or an antenna pattern 4, the antenna 4 being the electrically conductive line configuration of the an- tenna component 2.
  • the antenna structure 2 thus forms a part of the RFID tag 1 , which may be used in many different kind of applications.
  • RFID tags may, for example, be attached to different kind of items sold in department stores for storing specific information relating to the items they are attached to.
  • the antenna 4 provides means to transfer information between the RFID tag and a device intended for reading the information stored in the tag or a device intended for sending information to be stored in the tag.
  • the RFID tag 1 comprises further an integrated circuit 5 or chip 5 arranged in connection with the antenna 4, in order to store specific information relating to the item the RFID tag 1 is attached to.
  • the antenna structure 2 and the integrated circuit 5 attached to the antenna structure 2 are attached to a pressure sensitive adhesive, i.e. sticker 6 or some other kind of attachment element, thus providing a finished RFID tag 1 ready to be attached to the items to be sold in the department store, for example.
  • the sticker 6 has been schematically shown by a box with a broken line surrounding the antenna structure 2.
  • the RFID tag may also contain other layers laminated or otherwise attached to the structure.
  • the antenna 4 may comprise two resonant circuits, i.e. a radiating element 4' and a separate impedance matching element 4", which are elec- tromagnetically coupled together to achieve a desired frequency response of the antenna 4 together with the integrated circuit 5.
  • the frequency response of the impedance matching element 4" is affected by the inductance of the impedance matching element 4" and the input resistance and the input capacitance of the integrated circuit 5 connected to the impedance matching element 4".
  • the frequency response of the radiating element 4' is affected by the induc- tance, capacitance and radiation resistance of the radiating element 4'.
  • the impedances of the antenna 4 and the integrated circuit 5 needs to be suitably matched in order the circuitry to have a proper performance and frequency response.
  • the imped- ance matching element 4" and the radiating element 4' may be physically, i.e. galvanically, connected to each other over a coupling element 4"' but practi- cally the impedance matching element 4" and the radiating element 4' are coupled to each other via mutual inductance, i.e. the impedance matching element 4" having a certain resonance frequency is inductively coupled to the radiating element 4' having a certain resonance frequency.
  • a coupling distance D between the impedance matching element 4" and the radiating element 4' i.e. the shortest distance between the impedance matching element 4" and the radiating element 4' affects the frequency response of the antenna 4.
  • the specific antenna structure 2 shown in Figure 1 is given as an example only.
  • the separate impedance matching ele- ment 4" in addition to the radiating element 4' is typical for RFID tag antennas designed for UHF range.
  • the loop structure of the impedance matching element 4" may perform as the antenna without any additional radiating element.
  • the etching process variations in antenna manufacturing may alter physical dimensions of the antenna 4.
  • the variations of the physical dimensions of the antenna 4 means that the antenna pattern dimensions have some offset from the initial design target, which design target depends on the frequency range and type of the RFID tag in question.
  • the etching process varia- tions may result for example from the variations of the temperature and composition of the etchant or the time the etchant has an influence on the electrically conductive coating to be etched away.
  • the variations in the physical dimensions of the antenna cause electrical parameters of the antenna 4 to change, changing the antenna 4 frequency tuning, and impedance matching with the integrated circuit 5. This frequency tuning change can be further seen as shifts in performance so that the optimum performance of the antenna starts to degrade.
  • One factor of the frequency tuning changes is a change in the coupling distance D between the impedance matching element 4" and the radiat- ing element 4'. Changes in the coupling distance D alter further the impedance matching and the frequency response of the antenna 4 together with the integrated circuit 5.
  • the change in the coupling distance D after etching may be as high ⁇ 10%.
  • This kind of changes in the coupling distance D may have a significant effect on the performance of the an- tenna, the performance of the antenna starting to degrade for example such that the frequency response of the antenna becomes distinctively distorted. This may be observed in practice for example by some loss in reading distance of the RFID tag.
  • an antenna For improving the frequency characteristics it is known to provide an antenna with one or more loading bars that are placed adjacent to the ele- ments of the antenna at a spacing distance. By adjusting the loading bar length, width and/or spacing distance and/or the number of the loading bars, the input impedance of the antenna can be changed.
  • the antenna may be provided with one or more tuning stubs acting as two-conductor transmission line and which may be terminated either in a short-circuit or open- circuit.
  • tuning stubs and elements of the antenna the frequency characteristics of the antenna can be affected.
  • those features must be selected during the antenna design and the frequency characteristics deviations of the antenna occurring due to the process variations during the antenna etching cannot be compensated.
  • US-publication 6,535,175 discloses a RFID tag comprising an antenna including loading bars and tuning stubs that are physically alterable to selectively vary the performance characteristics of the antenna.
  • the loading bars and tuning stubs may each further comprise a variable selectable length having elements that may be removed for example by punching, cutting, etching or laser trimming for providing the desired frequency properties of the antenna.
  • US-publication 6,535,175 therefore discloses a solution which may take into account frequency characteristics deviations of the antenna occurred due to the process variations during the antenna etching.
  • the above mentioned measuring and adjusting steps create additional stages which increase overall costs in the RFID manufacturing.
  • the tuning element is designed to affect the electrical properties of the antenna structure in over- or under-etching situations such that the antenna structure will have after the etching process frequency response properties substantially corresponding to the frequency response properties of the designed target antenna structure.
  • This means that the tuning element will at least partly autocompensate or compensate automatically during the etching process the differences between the actual antenna structure being under etching and the etching target stage of the desired antenna line configuration, the etching target stage being the dimensional shape and geometry of the antenna line configuration which has been used as the basis for the design calcu- lations for the desired frequency response of the antenna structure.
  • under-etching situation i.e. in a case wherein not enough material is removed during etching and the desired etching target is thus not achieved
  • the under-etching tends to lengthen the electromagnetic length of the antenna structure and then the tuning element tends to shorten the elec- tromagnetic length of that antenna structure.
  • over- etching situation i.e. in a case wherein too much material is removed during etching and the desired etching target is not achieved for that reason, the over- etching tends to shorten the electromagnetic length of the antenna structure and then the tuning element tends to lengthen the electromagnetic length of that antenna structure.
  • the tuning element is thus designed to affect the electrical properties of the antenna structure during under- or over-etching situations in opposite direction compared to the other parts in the antenna structure.
  • the solution helps also to realize antenna structure designs that are much more insensitive to etching variations than prior art designs. Although the solution is not necessarily able to fully eliminate the change in the frequency performance of the antenna structure in all situations, it anyway helps to minimize the effects due to over- or under-etching.
  • the antenna structure may be used to form a part of a radio frequency identification transponder or tag comprising further an integrated circuit electrically connected with the antenna structure.
  • the antenna structure comprises an impedance matching element arranged to be connectable with an integrated circuit, a radiating element and further a coupling element arranged between the impedance matching element and the radiating element, the cou- pling element providing a radio frequency feeding point for the radiating element.
  • the tuning element may be designed to alter the effective electromagnetic length of at least one of the elements in the antenna structure as a function of the etching stage of the antenna structure, thus autocompensating up to a certain degree the deviation from the etching target stage.
  • the tuning element may be designed to alter the electromagnetic matching between the coupling element and the radiating element via affecting the radio frequency feeding point provided by the coupling element.
  • tuning elements are used in the same antenna design to simultaneously affect, for example, the effective electro- magnetic length of the antenna line configuration and the electromagnetic matching between two or more elements in the antenna structure, like between the coupling element and the radiating element.
  • Figure 1 shows schematically a top view of a prior art radio frequency identification tag
  • Figure 2 shows schematically a top view of another radio frequency identification tag comprising an antenna structure
  • Figures 3a and 3b show schematically a top view of an antenna line configuration and tuning elements arranged in connection with a coupling element of the antenna line configuration;
  • Figures 4a and 4b show schematically a top view of a second an- tenna and tuning elements arranged in proximity of a radiating element, an impedance matching element and a coupling element of the antenna;
  • Figures 5a and 5b show schematically a top view of a third antenna and tuning structures arranged in connection with an impedance matching element and a coupling element of the antenna;
  • Figures 6a and 6b show schematically a top view of a fourth antenna and tuning elements arranged in connection with an impedance matching element of the antenna;
  • Figures 7a and 7b show schematically a top view of a fifth antenna and tuning elements arranged in connection with a radiating element of the antenna;
  • Figure 8 shows schematically an example of the effect of tuning elements on a frequency response of an RFID tag comprising a double resonance antenna
  • Figure 9 shows schematically an example of the effect of tuning elements on a frequency response of an RFID tag comprising a single resonance antenna
  • Figure 10a shows schematically a single resonance antenna not comprising any tuning elements and figure 10b shows schematically a single resonance antenna comprising tuning elements and
  • Figures 1 1 a and 1 1 b show schematically a top view of an etching mask which can be used in the manufacturing of the antenna and tuning elements shown in Figure 4.
  • FIG. 2 shows schematically a top view of another radio frequency identification tag 1 or RFID tag 1 comprising an antenna structure 2.
  • the antenna structure 2 comprises a non-conducting substrate 3 and an electrically conductive line configuration corresponding to a dipole-like antenna 4 or antenna pattern 4.
  • the antenna 4 is manufactured by etching away locally by etchant an electrically conductive coating material supported by the substrate 3.
  • the antenna 4 comprises an antenna line configuration comprising a radiating element 4', an impedance matching element 4" and a coupling element 4"', the coupling element 4"' providing a radio frequency feeding point for the radiating element 4'.
  • the RFID tag 1 comprises further an integrated circuit 5 or chip 5 arranged in connection with the antenna 4 in the antenna structure 2, in order to store specific information relating to the item the RFID 1 will be attached to.
  • the antenna structure 2 and the integrated circuit 5 attached to the antenna structure 2 are attached to a pressure sensitive adhesive, e.g. sticker 6 or some other kind of attachment element, thus providing a finished RFID tag 1 .
  • the sticker 6 has been schematically shown by a box with a broken line and surrounding the antenna structure 2.
  • the RFID tag 1 may also contain other layers laminated or otherwise attached to the structure of the RFID tag 1 .
  • FIG 3a shows schematically a top view of an antenna 4 shown in Figure 2 after etching of the antenna structure 2 comprising the antenna 4.
  • Figure 3b shows a top view of a detail in Figure 3a.
  • the antenna 4 shown in Figures 2 and 3a is a dipole-like antenna 4 comprising an antenna line configuration comprising a radiating element 4', an impedance matching element 4" and a coupling element 4"'.
  • the coupling element 4"' there is one tuning element 7 at both sides of the coupling element 4"' such that there is a galvanic connection between the tuning elements 7 and the coupling element 4"', the tuning elements 7 thus being in connection with the coupling element 4"'.
  • the coupling element 4"' forms a feeding point of the radio frequency power from the impedance matching element 4" to the radiating element 4'.
  • the impedance matching element 4"' provides a proper matching with the integrated circuit 5.
  • the tuning elements 7 shown in Figure 3b comprise four tuning parts, i.e. tuning parts 7a, 7b, 7c and 7d, the tuning parts 7a being closest to the coupling element 4"' and the tuning parts 7d being farthest from the coupling element 4"'.
  • the tuning parts 7b and 7c are located between the tuning parts 7a and 7d such that the tuning part 7b is next to the tuning part 7a and the tuning part 7c is next to the tuning part 7d.
  • the tuning parts 7a, 7b, 7c and 7d have a form of bar and they have a certain width W and a certain length L, which may differ between the tuning parts 7a to 7d.
  • the tuning parts 7a, 7b, 7c and 7d are in connection with each others in the width direction of the tuning parts, i.e. the tuning parts 7a to 7d are in continuous series with each other.
  • the tuning parts 7a, 7b, 7c and 7d are thus arranged in the tuning elements 7 such that there is a galvanic connection between the tuning parts 7a, 7b, 7c and 7d, the tuning parts 7a, 7b, 7c and 7d thus forming a uniform or an unbroken tuning element area or tuning element pattern.
  • the tuning element 7 and thus the tuning parts 7a to 7d of the tuning element 7 are of the same electrically conductive coating material supported by the substrate 3 as the electri- cally conductive antenna line configuration of the antenna 4 and they are formed or manufactured by etching away locally by etchant the electrically conductive coating material at a same time or simultaneously within the same etching process as the electrically conductive antenna line configuration corresponding to the antenna 4. It is, however, possible that the shape and geome- try of the tuning element 7 is changed after the etching process by removing some amount of electrically conductive coating material away from the tuning element 7 or by adding some amount of electrically conductive coating material to the tuning element 7.
  • each of the tuning parts 7a to 7d has a different length L when compared to each other, such that the tuning part 7a is the longest one and the tuning part 7d is the shortest one.
  • the tuning part 7a, 7b, 7c and 7d and the radiating element 4' of the antenna 4 there is a small gap 8a, 8b, 8c and 8d such that there is no straight galvanic connection between the tuning parts 7a to 7d and the radiating ele- ment 4'.
  • the antenna structure 2 comprising the electrically conductive coating material supported by the substrate 3 is exposed to the effect of the etchant for forming the antenna 4 line configuration, i.e. the radiating element 4', the impedance matching element 4" and the coupling element 4"', and in the case of the embodiment according to Figures 3a and 3b, also the tuning elements 7.
  • the etchant removes the electrically conductive coating material from the substrate of the structure 2 on those parts of the substrate 3 not protected by the etching mask used.
  • the etching mask comprises barrier material on those parts of the substrate 3 wherein the designed electrically conductive antenna line configuration is desired to be maintained.
  • the basic principle of the etching process itself is generally known by a person skilled in the art and therefore it is not described more detailed here.
  • the etching process variations in antenna manufacturing for RFID tags may alter physical dimensions of the antenna line configuration.
  • the variations of the physical dimensions of the antenna 4 means that the antenna pattern dimensions have some offset from the initial design target.
  • the etching process variations may result for example from the variations of the temperature and composition of the etchant or the time the etchant has an influence on the electrically conductive coating material to be etched away.
  • the variations in the physical dimensions of the antenna cause electrical parameters of the antenna 4 to change, changing the antenna frequency tuning characteristics.
  • the frequency tuning change can be further seen as shifts in performance so that the optimum performance of the antenna starts to degrade.
  • the possible frequency tuning change due to possi- ble excessive effect of the etchant on the electrically conductive coating material or due to possible too small effect of the etchant on the electrically conductive coating material may be compensated to at least some degree already during the etching process of the antenna structure 2, i.e. during etching of the antenna 4.
  • the etchant removes the electrically con- ductive coating material not only on those portions of the electrically conductive coating material which are to be removed in order to obtain the designed target antenna pattern, but also from the portions forming the electrically conductive antenna line configuration corresponding to antenna 4 and the tuning elements 7.
  • Figures 8, 9, 10a and 10 show schematically examples of the effect of the tuning elements on the frequency response of the etched antenna configuration in the antenna structure.
  • Figure 4a shows schematically a top view of a second antenna 4.
  • FIG 4b shows a top view of a detail in Figure 4a.
  • the antenna 4 shown in Figure 4a is a dipole-like antenna 4 comprising a radiating element 4', an impedance matching element 4" and a coupling element 4"'.
  • the coupling element 4"' In connection with the coupling element 4"' there is one tuning element 7 at both sides of the coupling element 4"' such that there is no galvanic connection between the tuning elements 7 and the antenna 4 but the tuning elements 7 are arranged in proximity of the coupling element 4"'.
  • the tuning elements 7 shown in Figure 4b comprise four tuning parts, i.e. tuning parts 7a, 7b, 7c and 7d, arranged about similarly with respect to the radiating element 4', an impedance matching element 4" and a coupling element 4"' as in Figure 3b but in such a manner differently, that in the embodiment of Figure 4b the tuning parts 7a to 7d are separate from each other, i.e. there is no galvanic connection between the tuning parts 7a to 7d either.
  • the tuning parts 7a to 7d have again a form of bar and they have a certain width W and a certain length L, which may differ between the tuning parts 7a to 7d.
  • the tuning parts 7a to 7d thus form a non-uniform or broken tuning element area or tuning element pattern.
  • each of the tuning parts 7a to 7d has again a different length L when compared to each other, such that the tun- ing part 7a is the longest one and the tuning part 7d is the shortest one.
  • the tuning part 7a to 7d and the radiating element 4' of the antenna 4 there is a small gap 8a, 8b, 8c and 8d.
  • the dimension H between each of the tuning part 7a to 7d and the radiating element 4' and the dimension H' between each of the tuning part 7a to 7d and the impedance matching element 4" is thus different at a point of each of the tuning part 7a to 7d.
  • the effect of the etchant on the tuning element 7, i.e. on the tuning parts 7a to 7d is substantially similar as explained in connection with Figure 3b.
  • the etchant will remove material from each of the tuning part 7a to 7d of the tuning elements 7 such that the width W of each of the tuning part will decrease.
  • the compensation effect for compensating the possible changes of the frequency tuning characteristics of the antenna 4 due to the etching process variations is similar type as in the embodiment of Figures 3a and 3b such that the tuning elements 7 are used to compensate possible over- or under-etching at the radio frequency feeding point of the antenna 4 by changing the effective width of the coupling element 4"', thus improving the electromagnetic matching between the coupling element 4"' and the radiating element 4' and thus affecting in the electromagnetic performance of the whole antenna structure 2 by auto-compensating the ef- fects of possible over- or under-etching.
  • FIG 5a shows schematically a top view of a third antenna 4.
  • Figure 5b shows a top view of a detail in Figure 5a.
  • the antenna 4 shown in Figure 5a is a dipole-like antenna 4 too comprising a radiating element 4', an impedance matching element 4" and a coupling element 4"'.
  • the coupling element 4"' In connection with the coupling element 4"' there is one tuning element 7 at both sides of the coupling element 4"' such that there is galvanic connection between the tuning elements 7 and the impedance matching element 4" and the tuning elements 7 and the coupling element 4"', the tuning elements 7 thus being arranged in connection with the impedance matching element 4" and the coupling element 4"'.
  • the tuning elements 7 shown in Figure 5b comprise four tuning parts, i.e. tuning parts 7a, 7b, 7c and 7d, which are in galvanic connection with each other such that the tuning parts 7a to 7d form a uniform or unbroken tuning element area or tuning element pattern.
  • the tuning parts 7a to 7d have again a form of bar and they have a certain width W and a certain length L, which may differ between the tuning parts 7a to 7d.
  • the dimension H between each of the tuning part 7a to 7d and the radiating element 4' is thus different at a point of each of the tuning part 7a to 7d.
  • the effect of the etchant on the tuning element 7, i.e. on the tuning parts 7a to 7d is substantially similar as explained in connection with Figure 3b such that the tuning elements 7 are used to compensate possible over- or under-etching at the radio frequency feeding point of the antenna 4 by changing the effective width of the coupling element 4"', thus improving the electromagnetic matching between the coupling element 4"' and the radiating element 4' and thus affecting in the electromagnetic performance of the whole antenna structure 2 by auto-compensating the effects of possible over- or under- etching.
  • FIG 6a shows schematically a top view of a fourth antenna 4.
  • Figure 6b shows a top view of a detail in Figure 6a.
  • the antenna 4 shown in Figure 6a is again a dipole-like antenna 4 comprising a radiating element 4', an impedance matching element 4" and a coupling element 4"'.
  • the coupling element 4"' there is one tuning element 7 at both sides of the coupling element 4"' such that there is galvanic connection between the tuning elements 7 and the impedance matching element 4" of the antenna 4, the tuning elements 7 thus being arranged in connection with the impedance matching element 4" but in close proximity to or in proximity of the coupling element 4"'.
  • the tuning elements 7 shown in Figure 6b comprise four tuning parts, i.e. tuning parts 7a, 7b, 7c and 7d, arranged about similarly with respect to the radiating element 4', an impedance matching element 4" and a coupling element 4"' as in Figure 4b such that there is no straight galvanic connection between the tuning parts 7a to 7d.
  • the tuning parts 7a to 7d thus form a nonuniform or broken tuning element area or tuning element pattern.
  • the tuning parts 7a to 7d have again a form of bar and they have a certain width W and a certain length L, which may differ between the tuning parts 7a to 7d.
  • each of the tuning parts 7a to 7d has a different length L when compared to each other, such that the tuning part 7a is the longest one and the tuning part 7d is the shortest one. Between each of the tuning part 7a to 7d and the radiating element 4' of the antenna 4 there is a small gap 8a, 8b, 8c and 8d. The dimension H between each of the tuning part 7a to 7d and the radiating element 4' and the impedance matching element 4" is thus different at a point of each of the tuning part 7a to 7d.
  • the effect of the etchant on the tuning element 7, i.e. on the tuning parts 7a to 7d is substantially similar as explained in connection with Figure 4b such that the tuning elements 7 are used to compensate possible over- or under-etching at the radio frequency feeding point of the antenna 4 by changing the effective width of the coupling element 4"' as a function of the etching stage of the antenna structure (2), thus improving the electromagnetic match- ing between the coupling element 4"' and the radiating element 4' and thus affecting in the electromagnetic performance of the whole antenna structure 2 by auto-compensating the effects of possible over- or under-etching.
  • FIG 7a shows schematically a top view of a fifth antenna 4.
  • Figure 7b shows a top view of a detail in Figure 7a.
  • the antenna 4 shown in Figure 7a is again a dipole-like antenna 4 comprising a radiating element 4', an impedance matching element 4" and a coupling element 4"'.
  • the radiating element 4' there is one tuning element 7 at both ends of the radiating element 4' such that there is no galvanic connection between the tuning elements 7 and the radiating element 4' of the antenna 4 at one end of the tuning parts 7a to 7d.
  • the tuning elements 7 are thus arranged in close prox- imity or in proximity of the radiating element 4' of the antenna 4.
  • the tuning elements 7 shown in Figure 7b comprise four tuning parts, i.e. tuning parts 7a, 7b, 7c and 7d, arranged with respect to each other such that there is no straight galvanic connection between the tuning parts 7a to 7d.
  • the tuning parts 7a to 7d thus form a non-uniform or broken tuning ele- ment area or tuning element pattern.
  • the tuning parts 7a to 7d have again a form of bar and they have a certain width W and a certain length L, which may differ between the tuning parts 7a to 7d, but in the embodiment of Figure 7b each of the tuning parts 7a to 7d has a same length L when compared to each other.
  • the tuning elements 7 are used to compensate possible over- or under-etching at the radiating element 4' of the antenna 4 by changing the effective length of the radiating element 4", thus improving the frequency response characteristics of the radiating element 4'.
  • tuning elements 7 were arranged in proximity of or in close proximity to the radiating element 4' or the coupling element 4"' of the antenna 4 or in connection with the coupling element 4' of the antenna 4.
  • tuning elements 7 may also be used to compensate possible over- or under-etching of impedance matching element 4" for improving the electromagnetic matching between the antenna 4 and the integrated circuit 5.
  • One antenna structure 2 may also comprise several tuning elements 7 such that in the same antenna structure 2 may comprise, in any combination, tuning ele- ments 7 for radiating element 4', impedance matching element 4" and coupling element 4"'.
  • the physical dimensions of the antenna i.e. the effective length of the antenna 4 and/or the effective width of the antenna line configuration of the antenna 4 will be too small when compared to the physical dimensions of the designed target antenna, this meaning that the frequency tuning characteristics of the actual etched antenna 4 do not correspond to the frequency tuning characteristics of the designed target antenna, i.e. there is a change in the frequency tuning characteristics of the an- tenna.
  • Figure 8 shows schematically an example of the effect of tuning elements on a frequency response of an RFID tag comprising a double resonance antenna in an over-etching situation.
  • the example shown in Figure 8 substantially corresponds to the case presented in Figures 6a and 6b, the an- tenna presented in Figures 6a and 6b being one example of a typical double resonance design producing such a double resonance frequency response.
  • the frequency response shown in Figure 8 has two distinctive resonance peaks at the two ends of its frequency envelope marked with broken line. The first one of the peaks, i.e. the peak at a lower frequency, is due to the reso- nance circuit formed by the integrated circuit 5 and the impedance matching element 4". The resonance frequency of this circuit is marked with fjoop.
  • the second one of the peaks i.e. the peak at a lower frequency, is due to the resonance circuit formed by the integrated circuit 5 and the radiating element 4'.
  • the resonance frequency of this circuit is marked as f_radiator. Described in a simplified manner, the frequency response of an RFID tag is produce by the combined, coupled effect of these two resonance circuits producing the envelope frequency response with said two resonance peaks.
  • the corre- sponding resonance frequency fjoop decreases to a value of fjoop * which is clearly below the original frequency target value fjoop.
  • the reso- nance frequency f_radiator relating to the radiating element may become deviated from its target value f_radiator to the lower frequency f_radiator * because of the changes in the geometry of the radiating element 4' and also due to the affects between the integrated circuit 5 and the radiating element 4'.
  • the change in the radiating elements 4' resonance frequency due to over- etching may be rather small if compared to the changes in the resonance frequency fjoop relating to the impedance matching element 4' and in Figure 8 this change has been exaggerated.
  • the resonance frequencies fjoop * and f_radiator * are pulled closer to each other and the compensated frequency response determined by the resonance frequencies fjoop ** and f_radiator ** is closer to the original target frequency response.
  • the second example shown in Figure 9 relates to a so-called single resonance antenna design.
  • an RFID tag comprising such a single resonance antenna has a frequency response envelope comprises only one resonance frequency peak arising mainly from the resonance circuit formed between the integrated circuit 5 and the radiating element 4'.
  • Figure 10a shows an example of an antenna design producing such a single resonance peak frequency response. From Figure 10a it can be seen that it does not comprise a similar separate impedance matching element structure between the integrated circuit 5 and the radiating element 4' that the design shown in Figure 6a, for example.
  • an RFID tag resonance frequency f ag decreases to a value f ag * , which is clearly below the original frequency response.
  • the autocompensation provided by the tuning elements 7 for the radiating element 4' as shown schematically in Figure 10b at the ends of the radiating element 4' pull or push the resonance frequency higher to a value of f_tag ** , thus closer to the original resonance frequency f_tag.
  • the tuning elements suitably and by selecting the places or locations of the tuning elements suitably the possible too strong ef- feet or too low effect of the etchant on the electrically conductive coating material during etching of the antenna may be automatically compensated already at the etching phase so that the finished, etched antenna has the desired elec- tromagnetically effective length and or width and thus the desired frequency tuning characteristics after the etching process has finished.
  • the effect of pos- sible too strong effect or too low effect of the etchant on the electrically conductive coating material during etching can thus be eliminated already during the etching process itself.
  • the finished RFID tags will have actual frequency tuning characteristics, which essentially correspond to the designed frequency tuning charac- teristics.
  • Figures 1 1 a and 1 1 b show schematically a top view of an etching mask 9 which can be used in the manufacturing of the antenna structure 2 comprising an antenna disclosed in Figures 4a and 4b.
  • the etching mask is used to control locally removal and maintenance of the electrically conductive coating material by using etchant.
  • the etching mask 9 according to Figures 1 1 and 1 1 b in arranged on top of the substrate 3 comprising electrically conductive coating material, the substrate 3 being schematically shown for example in Figure 2.
  • the etching mask 9 comprises etching mask material or barrier material on a first main area 10, on the second main area 10' and on the third main area 10" of the etching mask 9, the shape of the first main area 10 corresponding to the shape of the radiating element 4' of the antenna 4 to be maintained during etching, the shape of the second main area 10' corresponding to the shape of the impedance matching element 4" of the antenna 4 to be maintained during etching and the shape of the third main area 10" corresponding to the shape of the coupling element 4"' of the antenna 4 to be maintained during etching.
  • the etching mask 9 comprises further barrier material on the sub-areas 1 1 being located at both sides of the third main area 10", the sub-areas 1 1 corresponding to the areas of the tuning elements 7 disclosed in Figures 4a and 4b.
  • the sub-areas 1 1 comprise four lines or bars of barrier material having different widths W and lengths L with respect to each other, i.e. bars 1 1 a, 1 1 b, 1 1 c and 1 1 d, for forming lines or bars of electrically conductive coating material corresponding the tuning parts 7a, 7b, 7c and 7d of the tuning elements 7 disclosed in Figures 4a and 4b.
  • the length L and/or width W of the bars 1 1 a, 1 1 b, 1 1 c and 1 1d may vary between the bars 1 1 a, 1 1 b, 1 1 c and 1 1 d.
  • the etching mask 9 is arranged on top of the electrically conductive coating material supported by the substrate 3 such that in the first phase the whole area of the substrate is coated by mask material or resist material. After that the mask pattern is exposed in the mask material and then either the exposed or un-exposed part of the mask material is removed by etchant, depending whether positive or negative photoresistive mask material is used. In the etching of antennas typically negative photoresistive mask material is used. Also other kind of ways generally known for the person skilled in the art are available for arranging the etching mask 9 on top of the substrate 3, such as the use of different kind of etchant resistive protective materials, such as paint, for example. However, the above explained method being based on the photolithography is the most used in the etching of fine patterns or line configurations.
  • the antenna structure 2 After the etching mask 9 according to Figures 1 1 a and 1 1 b on top of the antenna structure 2 panel or billet comprising a substrate 3 comprising electrically conductive coating material, etchant is applied on the antenna structure panel.
  • the etchant removes the electrically conductive coating material on the parts of the coating not protected by the barrier material, such that the electrically conductive coating material remains in the areas corresponding to the first 10, second 10' and third 10" main areas and the two sub-areas 1 1 of the etching mask.
  • the antenna structure 2 comprises both the electrically con- ductive antenna line configuration corresponding to at least to some extent the designed target antenna pattern and the tuning elements.
  • Other parts of the electrically conductive coating material have been removed by etchant away from the antenna structure 2.
  • Figures 1 1 a and 1 1 b it has been schematically disclosed a top view of an etching mask 9 which can be used in the manufacturing of the antenna structure 2 comprising an antenna disclosed in Figures 4a and 4b.
  • the presence and the shape of the first 10, second 10' and third 10" main areas depends on the specific antenna line con- figuration and that the number, shape and location of the sub-areas 1 1 in the etching mask may vary respectively for example in the same manner as the number, shape and location of the tuning elements 7 vary in above examples.

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  • Details Of Aerials (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)

Abstract

La présente invention concerne une structure d'antenne (2) comprenant au moins un substrat non conducteur (3) et une configuration de ligne d'antenne électroconductrice (4', 4'', 4''') portée par le substrat (3), la configuration de ligne d'antenne électroconductrice (4', 4'', 4''') étant formée au cours d'un processus de gravure par retrait local par gravure, à l'aide d'un agent de gravure, d'un matériau de revêtement électroconducteur porté par le substrat (3). La structure d'antenne (2) comprend en outre au moins un élément de réglage électroconducteur (7) du même matériau de revêtement électroconducteur. L'élément de réglage (7) est au moins en partie formé simultanément avec la configuration de ligne d'antenne électroconductrice (4', 4'', 4''') au cours du même processus de gravure, l'élément de réglage présentant, après le processus de gravure, une forme et une géométrie dimensionnelles pour compenser au moins en partie l'effet de gravure excessive ou de gravure insuffisante dans les propriétés électriques de la structure d'antenne (2).
PCT/FI2010/050516 2010-06-17 2010-06-17 Procédé de fabrication d'une structure d'antenne à auto-compensation par gravure WO2011157883A1 (fr)

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CN201080068119.2A CN103181024B (zh) 2010-06-17 2010-06-17 通过蚀刻制造自动补偿天线结构的方法
PCT/FI2010/050516 WO2011157883A1 (fr) 2010-06-17 2010-06-17 Procédé de fabrication d'une structure d'antenne à auto-compensation par gravure
KR1020137001201A KR101664263B1 (ko) 2010-06-17 2010-06-17 에칭에 의해 자동 보상 안테나 구조물을 제조하기 위한 방법

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CN103219586A (zh) * 2012-01-18 2013-07-24 太盟光电科技股份有限公司 平板天线的自动检测修正调整方法及其系统
WO2014022483A1 (fr) * 2012-07-31 2014-02-06 Molex Incorporated Doublet symétrisé par coaxial fendu
WO2017197807A1 (fr) * 2016-05-20 2017-11-23 中兴通讯股份有限公司 Circuit et procédé pour ajuster la bande de fréquence d'une antenne, et dispositif électronique
US20200153102A1 (en) * 2017-10-03 2020-05-14 Intermec, Inc. Wideband rfid tag antenna

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CN103811858B (zh) * 2014-01-28 2016-07-06 杭州电子科技大学 Rfid标签天线及对应光盘
CN103811873B (zh) * 2014-01-28 2016-06-15 杭州电子科技大学 标签天线及对应光盘
DE102017121897B4 (de) * 2017-09-21 2019-05-02 Infineon Technologies Ag Verfahren zum Herstellen einer Antennenstruktur, Antennenstruktur, Boosterantenne, Chipkarte und Einrichtung zum Herstellen einer Antennenstruktur

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CN103219586A (zh) * 2012-01-18 2013-07-24 太盟光电科技股份有限公司 平板天线的自动检测修正调整方法及其系统
CN103219586B (zh) * 2012-01-18 2015-08-05 太盟光电科技股份有限公司 平板天线的自动检测修正调整方法及其系统
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WO2014022483A1 (fr) * 2012-07-31 2014-02-06 Molex Incorporated Doublet symétrisé par coaxial fendu
WO2017197807A1 (fr) * 2016-05-20 2017-11-23 中兴通讯股份有限公司 Circuit et procédé pour ajuster la bande de fréquence d'une antenne, et dispositif électronique
US10826198B2 (en) 2016-05-20 2020-11-03 Zte Corporation Circuit and method for adjusting frequency band of antenna, and electronic device
US20200153102A1 (en) * 2017-10-03 2020-05-14 Intermec, Inc. Wideband rfid tag antenna
US11527832B2 (en) * 2017-10-03 2022-12-13 Intermec, Inc. Wideband RFID tag antenna

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KR101664263B1 (ko) 2016-10-10
CN103181024A (zh) 2013-06-26
CN103181024B (zh) 2015-11-25
KR20130036116A (ko) 2013-04-10
WO2011157883A8 (fr) 2012-03-15

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