SK, TR), OAPI (BF, BJ, CF, CG, Cl, CM, GA, GN, GQ, For two-letter codes and other abbreviations.) Refer to the. "Guid-GW, ML, MR, NE, SN , TD, TG.) Anee Notes on Codes and Abbreviations "appearing at the beginning of .ach regular issue of the PCT Gazette. Published: - wilh intemational search reportSECURITY LABEL WITH ANTENNA DISPOSITIONTHREE-DIMENSIONAL MADE OF PLANT SUPPLY MATERIALAND MANUFACTURING METHOD FOR THE SAMEFIELD OF THE INVENTIONThis invention relates to security labels and, very particularly, to a dipolar ultra-high frequency (UHF) antenna system for a radio frequency identification (RFID) tag that optimizes detection for a given available volume in the which place the label ofRFIDDESCRIPTION OF THE RELATED TECHNIQUELow-cost labels manufactured by continuous feeding processes are normally formed of label supply material and are therefore two-dimensional. The performance of two-dimensional labels is generally a strong function of the antenna orientation of the label in relation to the interrogator and reader label. An approach used to reduce the sensitivity of the labels to their orientation with respect to the interrogator / reader includes increasing the effective area of the label antenna so that more energy is extracted from the incident electromagnetic field. Another approach, used with dipole antennas, is to orient two or more antennas at angles with respect to each other within the plane of the supply material of the label. However, the two approaches mentioned above result in a larger label, adding manufacturing expense and reducing marketing. To adapt the use of two dipole antennas in labels ofRFID, a company, Matrics, Inc. of Rockville, Maryland, has developed an RFID IC system (e.g., over Matrics Tag X1020) that provides a plurality of RF inputs along with a terrestrial terminal. However, especially where the UHF frequencies (e.g., 850 MHz-950 MHz) and microwave frequencies (e.g., 2.3 Ghz-2.6)Ghz) are used in communication with RFID tags, there is a need for a UHF (or microwave) dipole antenna system that optimizes detection for a given volume in which the RFID tag is located. All references cited herein are incorporated herein by reference in their entirety.
BRIEF DESCRIPTION OF THE INVENTIONAn antenna configuration for use in a security tag (e.g., an RFID security tag) that optimizes the reception of a signal emitted from an interrogator or reader. The antenna configuration comprises: a first dipole and a second dipole arranged in a non-collinear or parallel configuration to form a plane (e.g., a sheet-like material) comprising the first and second dipoles; and a trecer dipole being located outside the plane. A method for manufacturing a three-dimensional antenna for a security tag (e.g., an RFID security tag) to optimize the reception of a signal emitted from an interrogator or reader. The method comprises the steps of: (a) providing a material in the form of a sheet (eg, substrate, flat supply material, paper, plastic, etc.); (b) forming a first dipole and a second dipole on the sheet material and wherein the first dipole and the second dipole are formed so that they are not collinear or parallel with respect to each other; (c) forming a third dipole on the sheet material; (d) cutting the sheet material to release a portion of the third dipole of the sheet material; and (e) displacing the free portion of the sheet material.
BRIEF DESCRIPTION OF THE DIVERSE VIEWS OF THE DRAWINGSThe invention will be described in conjunction with the following drawings in which like reference numerals designate similar elements and wherein: Figure 1 is a functional diagram of the security label with three-dimensional antenna; Figure 1A are Cartesian coordinate axes; Figure 2A illustrates a part of a substrate containing the RFID integrated circuit and the antenna cables for the three-dimensional antenna as part of the substrate during the manufacture of the label; Figure 2B shows how two of the antenna cables are lifted from the substrate to form the dipolar antenna on the third axis (z); Figure 2C are reference Cartesian coordinate axes; Figure 3 is a diagram in a plan view of label supply material with multiple elements stretched in two dimensions; Figure 4 is a diagram in isometric view of an embedded tag with antenna elements bent to be in three dimensions; Figure 4A are Cartesian coordinate axes of reference for the second embodiment; and Figure 5 is a diagram in isometric view of a folded label installed in a back shell of a hard label housing.
DETAILED DESCRIPTION OF THE INVENTIONThose skilled in the art will appreciate that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It will be understood, therefore, that this invention is not limited to the particular embodiments described, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
With the number 20 in Figure 1 there is shown an RFID security tag comprising a three-dimensional antenna. The RFID security tag 20 comprises three dipole antennas coupled to an integrated RFID (IC) circuit 22. A dipole antenna on the x-axis (see Figure 1A for axis orientation) comprises antenna strands X1 and X2. A dipolar antenna on the y axis comprises antenna ropes Y1 and Y2. Finally, a third dipole antenna on the z axis comprises antenna ropes Z1 and Z2. This RFID security tag 20 can be packaged in a housing, e.g., a ball-shaped housing, a cube-shaped housing, etc. The RFID 20 security label is ideal for placement on boarding pallets, for example, or for incorporation in packaging or shipping materials. The presence of a dipole in the three dimensions optimizes the detection, by the RFID tag 20, of a signal emitted from an interrogator or reader (not shown) for a given volume in which the tag 20 is present, especially for signals in the frequency range of UHF (e.g., 850 MHz-950 MHz) and in the microwave range (e.g., 2.3 Ghz-2.6 Ghz). Therefore, the three-dimensional antenna forms an improvement over a two-dimensional antenna and operates better than a single straight or wave dipole antenna. A very economical method for producing the z-axis dipole is to use safety supply flat material material procedures to create all the dipoles. In particular, as shown in Figures 2A-2B, the three dipoles are fabricated on a flat sheet of sheet material (Figure 2A) and electrically coupled to the RFID IC 22. In a subsequent step, the shaped material The leaf that connects one of the dipoles is cut (see lines C in Figure 2A), allowing the free end (FE) of each dipole line to bend from the xy plane (Figure 2B) and perpendicular to the other two dipoles (Figure 2B). see figure 2C for axis orientation). The dipole antennas of the RFID tag 20 of the present invention can be produced using conventional methods using etching, printing (e.g., copper or silver inks, flexographic printing), die cutting, laser cutting, etc. The sheet material 24 can comprise any flat supply material or substrate including paper or plastic, etc. In the preferred embodiment, the thickness of the sheet material 24 could be in the range of 25 to 90 microns; the antenna ropes X1-Z2 or elements 122/124 (see Figures 3-5 and corresponding text), eg, trace metal, could be in the range of 7 to 60 microns or more. However, those skilled in the art know that the thickness of the sheet material 24 and the antenna ropes X1-Z2 / elements122/124 are not restricted in any way to those intervals and those intervals do not limit the scope of the invention in any way. In fact, it is within the broadest scope of the present invention to include antenna ropes / elements that are embedded in the sheet material 24, including where the antenna ropes / elements are flush with the surface of the material in question. blade shape 24. RFID IC 22 can be electrically coupled to the antenna strands using wire bonding, reversible eyelet methods, contact gluing, etc. The coupling of the ropes / elements to the RFID IC 22 can be achieved using rectifiers and even multiplexers to provide the signals received from the various dipoles to the RFID IC 22. Therefore,, it is within the broadest scope of the present invention to include any method whereby the ends of all of the dipoles are formed on or within the substrate and then electrically coupled to the RFID IC 22. In addition, it is also within the broad range. scope of the present invention to include the security label manufacturing procedures described in the US patent application with serial number 60 / 547,235 entitled Security Tags, Apparatus and Methods for Making the Same, filed on February 23, 2004 or described in the patent application of E.U.A. with serial number 10 / 235,733 entitled Security Tag and Process for Making the Same, filed on September 5, 2002, both entire descriptions are hereby incorporated by reference and the two of which are owned by the same assignee, namely Checkpoint Systems, Inc., than the present application. The same antenna strands (X1-Z2) can include adjustment strands that can be cut-off bars and support for impedance matching that can be modified by appropriate adjustment (eg, inline adjustment of the dipoles while they lie on / within the substrate) the three dipoles before the z-axis ends Z1 and Z2 are lifted from the xy plane. It should be noted that although the preferred embodiment includes a third dipole (ends Z1 / Z2) that is orthogonally oriented with respect to said first and second dipoles, it is within the broader scope of the present invention to include a third dipole having ends that are located outside the xy plane and formed by the first and second dipoles but which are not necessarily orthogonal to that plane. Therefore, the angles? I and? 2 shown in Fig. 2B can be between 0o and 90 ° with respect to a horizontal reference line in the x-y plane. Moreover, it is also within the broader scope of the invention where the angles? I and? 2 are not equal. With reference to figure 3, another mode 120 is shown(ie, a plan view) of a two-dimensional antenna arrangement having multiple dipole elements formed on the label supply material 24 for use with electronic article survival (EAS) and RFED tags. In particular, two bent dipole elements are shown in this mode 120, an outer element 122 around the perimeter of the cut tag supply material 24 and an internal element 124 within the area of the outer element 122 (the RFID IC 22 is not shown). ). The internal element 124 comprises dipole strands 124A and 124B. Preferably, internal elements 124 and external elements 122 are formed on the non-conductive label supply substrate 24 by any of the various label manufacturing methods (all of which were described above for label 20 and all of which are applicable to the label). mode 120) which results in an electrically conductive trace forming the antenna ends. Said methods include, but are limited to, die cutting, conductive ink printing, recording a conductive sheet and additive electrolytic deposition. The substrate is preferably a polymeric material but could be another substantially non-conductive material such as paper. Referring to Figure 4, mode 120 of Figure 3 is shown bent towards a three-dimensional antenna arrangement. The three-dimensional antenna arrangement is formed from the two-dimensional antenna arrangement by cutting the substrate 24 (which is in the xy plane, see Figure 4A) around the periphery of the internal member 124 using die cutting or a similar procedure, and by folding the inner element 122 in an upright position, the plane of which is at an angle to the xy plane of the external element 122. Figure 5 shows the internal element 124 of the antenna of Figure 4 at an angle substantially perpendicular to the element external 122, installed within the rear shell 126 of a hard tag housing (e.g., a reusable security tag), including a portion of a lock housing 10. In contrast to the preferred embodiment 20, the second embodiment 120 is formed having both dipole strands 124A and 124B on the same side of the flat supply material 24. It should be noted that although the internal element 124 of the second embodiment 12 0 is originally oriented with respect to the external element 122, is within the broader scope of the present invention to include an internal element 124 having strands 124A / 124B that are located outside the xy plane and formed by the outer element 122 but are not necessarily orthogonal to that plane. Therefore, the angles TA and TB shown in Figure 4 can be between 0o and 90 ° with respect to a horizontal reference line in the x-y plane. Moreover, it is also within the broad scope of the invention where the angles TA and TB are not equal. The three-dimensional antenna arrangement as shown in Figures 1-5 is not limited to the specific implementation of the specific modalities. For example, internal elements 124 and external 122 do not need to be bent dipoles but could be another configuration of antennas such as loops, and the arrangement could be a combination of several antenna element configurations such as loops and dipoles. In addition, the elements of the two-dimensional antenna do not need to be formed within one another, but could be adjacent to each other. Also, the number of elements may be more than two and the elements may be oriented at arbitrary angles with respect to each other and still be within the spirit of the invention. As would be clear to those skilled in the art, by extending the antenna array in a third dimension, the performance of the antenna array is improved relative to the size of the tagging supply material consumed to form the antenna array. By maintaining the same area as a two-dimensional antenna array, the performance of the antenna array is increased without increasing the cost of the tag. Alternatively, the antenna area can be reduced to achieve the same performance as a two-dimensional antenna array but in a less expensive tag. Although the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.