Wideband non-foldable on-metal UHF RFID tag

Abstract

According to some embodiments, a wideband, non-folding, on-metal UHF RFID tag is disclosed. The wideband, non-folding, on-metal UHF RFID tag 100 may include a substrate and an antenna. The antenna may include a first dipole antenna having a first notched groove, a second dipole antenna having a second notched groove, and first and second loop antennas disposed within a central region of the antenna. The wideband, non-folding, on-metal UHF RFID tag 100 may include an RFID chip embedded in the center of the central region of the antenna, and a dielectric substrate bonded to the underside of the antenna and the RFID chip.

Description

[Technical Field]

[0001] The present invention relates generally to RFID inlays or tags, and more particularly to wideband non-folding on-metal UHF RFID tags. [Background technology]

[0002] Radio Frequency Identification ("RFID") uses electromagnetic energy ("EM energy") to stimulate or interrogate a transponder (known as an RFID "tag," inlay, or transponder) to identify itself and, in some cases, provide additional stored data. RFID tags typically contain semiconductor devices such as integrated circuits (ICs), commonly referred to as ICs or "chips." The chip contains the tag's memory and operating circuitry and is connected or otherwise coupled to an antenna.

[0003] Typically, RFID tags provide information stored in chip memory in response to radio frequency ("RF") interrogation signals received from a reader, also known as an interrogator. For passive RFID tags (i.e., RFID tags without an internal power source), such as ultra-high frequency ("UHF") RFID tags, the energy of the interrogation signal generates a potential difference across the chip, providing the energy necessary to operate the RFID tag. However, when an RFID tag is attached to a metal surface, the amount of energy received by the antenna can be significantly reduced because the metal acts as a conductive surface and can block, reflect, or otherwise adversely interfere with the RFID tag's propagation operation. Additionally, the proximity of a metal surface to an RFID tag can introduce additional reactance into the RFID tag's circuitry. For example, the antenna's resonant frequency can be altered, reducing or destroying the impedance match between the antenna and the chip, rendering the tag unable to be read at the desired read range or otherwise inoperable.

[0004] The above issues pose significant challenges for users attempting to tag metal objects. For example, many components of packages, container shipping, and objects are at least partially metallic, negatively impacting the ability to utilize RFID technology to tag the components. Additionally, many companies use metal packaging as a means of unique and distinctive branding. Therefore, there is a need for RFID tags that can be attached or adhered to metal surfaces without significantly or partially attenuating the input signal. However, conventional UHF RFID tags used on such metal objects and packaging are applied with differential adhesion, indirect adhesion, or away from the metal or conductive surface to prevent shorting and / or degradation of the attached UHF RFID tag.

[0005] Subsequently, "on-metal" tags were introduced. Known on-metal tags are implemented with a dipole antenna and are provided with a dielectric substrate placed between the metal surface and the dipole antenna so that no potential difference is developed across the antenna during exposure to RF signals. Traditionally, on-metal tags have been over-engineered, requiring additional manufacturing process steps and materials, increasing costs.

[0006] Known UHF RFID-on-metal tags can operate at a single read frequency received from an RFID reader. In fact, the operating frequency of UHF RFID readers varies by geographic location, depending on national or regulatory standards. For example, the allowable UHF operating range varies significantly between geographic locations, such as Europe (which may be defined by ETSI as approximately 860-875 MHz) or the United States (which may be defined by the FCC as approximately 890-930 MHz). Therefore, conventional UHF RFID-on-metal tags must be specifically configured or designed with an operating resonant frequency for only one geographic location, and will not operate or will not be optimally operable in other geographic locations. Furthermore, because conventional UHF RFID-on-metal tags design and configure their antennas to resonate at a single resonant frequency, they are also limited by transmission loss due to differences in impedance matching while operating at that resonant frequency. In fact, as supply networks become more globalized, such UHF tags must operate in different geographic locations.

[0007] Therefore, in view of the above, there is a need to overcome the limitations and shortcomings associated with conventional UHF RFID tags for tagging metal surfaces, and for the antenna of a UHF RFID on-metal tag to operate at a different resonant frequency. Summary of the Invention [Problem to be solved by the invention]

[0008] Described herein are wideband, non-folding, on-metal UHF RFID tags for tagging metal or other conductive surfaces, and methods of making and operating the same. In some embodiments, the wideband, non-folding, on-metal tags are configured to operate at multiple resonant frequencies. [Means for solving the problem]

[0009] In some embodiments, the tag includes or contains a dielectric substrate located between the tag and a metal or conductive surface to create a potential difference and prevent short circuits therein when exposed to an input radio frequency signal. In some embodiments, the tag includes a dipole and a loop antenna, operating synchronously to resonate at multiple resonant frequencies. In some embodiments, the tag is as described above, and the tag is an ultra-high frequency (UHF) tag.

[0010] In some embodiments, the tag is as described above and further includes or contains an antenna configured for impedance matching. In some embodiments, the antenna includes or contains a first dipole antenna having a first notch and a second dipole antenna having a second notch. In some embodiments, the first and second notches are grooves.

[0011] In some embodiments, the tag is as described above and further includes a first loop antenna and a second loop antenna disposed within a central region of the antenna.

[0012] In some embodiments, the tag includes or contains a chip embedded in the center of the central region of the antenna. In some embodiments, the RFID chip defines the shape and dimensions of the antenna according to the impedance matching requirements of multiple resonant frequencies when exposed to an input RF signal from an RFID reader. In some embodiments, the chip is electronically, magnetically, or capacitively coupled to the antenna.

[0013] In some embodiments, the tag is as described above, wherein the first loop antenna is coupled to the first dipole antenna via a first coupling region and the second loop antenna is coupled to the second dipole antenna via a second coupling region. In some embodiments, the first loop antenna includes a first elongated slot and the second loop antenna includes a second elongated slot. The antenna is configured to operate at a resonant frequency in the ultra-high frequency range. The antenna is also configured to operate at a resonant frequency of 860 MHz or 910 MHz. In some embodiments, the antenna is tuned to match the inductive reactance of the antenna to the impedance of an input signal, and the chip is configured to match impedance at multiple frequencies when exposed to an input RF signal from an RFID reader. Impedance matching is configured on the antenna by adjusting the length of the first and second notched grooves, the depth of the first and second notched grooves, the length of the first and second loop antennas, or the load reactance of the RFID chip.

[0014] In some embodiments, methods of using the tags described herein are also provided. In some embodiments, the methods include transmitting a received input signal via an antenna to an RFID chip of the tag. In some embodiments, the methods further include triggering the RFID chip to resonate at at least two matched resonant frequencies, one at a time, in response to the received input signal. In some embodiments, the methods further include retransmitting an output signal from the RFID chip to the antenna and radiating the output signal via the antenna. In some embodiments, the first dipole antenna and the second dipole antenna are tuned to resonate at a first resonant frequency, and the first loop antenna, the second loop antenna, and the RFID chip are tuned to resonate at a second resonant frequency.

[0015] In some embodiments, a method for manufacturing a broadband non-folding on-metal tag is also provided. The method includes providing a single metal sheet, such as an aluminum sheet or foil. The metal sheet is cut to form antennas. The method also includes constructing a first dipole antenna having a first notched groove and a second dipole antenna having a second notched groove from the antenna. In some embodiments, the method also includes forming a first loop antenna and a second loop antenna within a central region of the antenna.

[0016] These and other features, aspects, embodiments, and advantages of the present invention will become better understood with reference to the following description and appended claims. This Summary is provided to introduce selected concepts in a simplified form. It is not intended to identify key features or essential features of the claimed or disclosed invention, nor is it intended to limit the scope of the claimed invention.

[0017] The foregoing summary and the following detailed description of exemplary embodiments will be best understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the invention, there are shown in the drawings exemplary configurations of the invention. However, the invention is not limited to the specific methods and instrumentalities disclosed herein. Also, persons skilled in the art will appreciate that the drawings are not to scale. Wherever possible, like elements will be designated by like numerals.

[0018] Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which: [Brief explanation of the drawings]

[0019] [Figure 1A] 1 is an illustration of a perspective view of a wideband non-folding on-metal UHF RFID tag, according to an embodiment. [Figure 1B] 1 is an illustration of a plan view of a wideband non-folding on-metal UHF RFID tag, according to an embodiment. [Figure 2]1 is a graph illustrating the resonant frequency and read range of a wideband non-folding on-metal UHF RFID tag and a conventional tag, according to an embodiment. [Figure 3] 1 is an illustration of a graph showing the resonant frequency of a wideband non-folding on-metal UHF RFID tag for various widths of the coupling region, according to an embodiment. [Figure 4A] 10 is an illustration of a wideband non-folding on-metal tag for various lengths of the loop antenna depending on the inductive reactance loading of the attached RFID chip, according to an embodiment. [Figure 4B] 1 is an illustration of a graph showing the resonant frequency of a wideband non-folding on-metal UHF RFID tag for various lengths of the loop antenna as a function of the inductive reactance loading of the attached RFID chip, according to an embodiment. [Figure 5A] 1 is an illustration of a wideband non-folding on-metal UHF RFID tag including a notched groove with a notched width, according to an embodiment. [Figure 5B] 10 is an illustration of a graphical representation of a graph showing the resonant frequency of a wideband non-folding on-metal UHF RFID tag for various notch widths of the notched groove, according to an embodiment. [Figure 5C] 1 is an illustration of a wideband non-folding on-metal UHF RFID tag including a notched groove with a notched depth, according to an embodiment. [Figure 5D] 10 is an illustration of a graph showing the resonant frequency of a wideband non-folding on-metal UHF RFID tag for various notch depths of the notched groove, according to an embodiment. [Figure 6] 1 is a flowchart of a method of operation of a wideband non-folding on-metal UHF RFID tag in accordance with an exemplary embodiment of the present invention. [Figure 7] 1 is a flowchart of a method for manufacturing a broadband non-folding on-metal tag, according to an embodiment.

[0020] In the accompanying drawings, underlined numbers are used to indicate the item in which the underlined number is located or to which it is adjacent. Numbers without underlines relate to the item identified by the line connecting the ununderlined number to the item. When a number is not underlined and has an associated arrow, the ununderlined number is used to identify the general item to which the arrow is pointing. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following detailed description describes various embodiments of the present invention and how it may be implemented. While certain modes of carrying out the present invention are disclosed, those skilled in the art will recognize that other embodiments are possible for carrying out or performing the present invention. Some embodiments disclosed herein include one or more methods, devices, and / or systems for tagging metal or conductive surfaces with UHF RFID tags.

[0022] In some embodiments, a wideband non-folding on-metal UHF RFID tag is provided. The wideband non-folding on-metal UHF RFID tag comprises: a first dipole antenna having a first notched groove; a second dipole antenna having a second notched groove; an antenna including a first loop antenna and a second loop antenna disposed within a central region of the antenna; and an RFID chip embedded in the center of the central region of the antenna.

[0023] In some embodiments, a method of operation of a broadband non-folding on-metal tag is provided, the method comprising: receiving an input signal of a predefined frequency via an antenna of a UHF RFID tag; transmitting the received input signal via an antenna to an RFID chip of a UHF RFID tag; triggering the RFID chip to resonate at least two matched resonant frequencies one at a time in response to the received input signal; retransmitting the output signal from the RFID chip to the antenna; and radiating the output signal via an antenna.

[0024] In yet another aspect, some embodiments of the present invention provide a method of manufacturing a broadband non-folding on-metal tag, the method comprising: cutting a metal sheet to form an antenna; generating a first dipole antenna having a first notched groove and a second dipole antenna having a second notched groove from the antenna; forming a first loop antenna and a second loop antenna disposed within a central region of the antenna.

[0025] Throughout this specification, the term "on-metal tag" refers to a radio frequency identification tag, such as a UHF RFID tag, a smart tag, or other ultra-high frequency tag. In various embodiments, the radio frequency identification tag enables or supports efficient, cost-effective, and time-saving item identification for locating, identifying, and tracking desired items. Also, as used herein, in some embodiments, the radio frequency identification tag can determine information regarding an item's location, item availability, or presence, and a response signal for a selected or desired item. In particular, various embodiments relate to an ultra-high frequency UHF RFID tag placed on metal for tracking metal objects or objects having a metallic or conductive surface. Specifically, when the RFID reader is activated, a UHF RF signal is transmitted from the RFID reader. In such a case, when the UHF RFID tag is exposed to the UHF RF signal, the antenna of the UHF RFID tag receives the UHF RF signal along with information stored on the RFID tag chip and retransmits it to the reader.

[0026] 1A and 1B are illustrations of a perspective view and a plan view of a wideband, non-folding, on-metal UHF RFID tag 100, respectively, according to an embodiment.

[0027] In some embodiments, the wideband non-folding on-metal UHF RFID tag 100 may include, for example, an item identification system, an item location system, or an item display system. As used herein, an item identification system includes item identification, item location, and item display in one or more embodiments within the scope of the present invention.

[0028] In various embodiments, the broadband non-folding on-metal UHF RFID tag 100 includes a substrate 102. As used herein, the substrate 102 is a non-metallic layer fabricated using, for example, a polymeric material, paper, etc. The substrate 102 is provided to support the broadband non-folding on-metal UHF RFID tag 100 and components attached and / or mounted therein.

[0029] In some embodiments, the wideband non-folding on-metal RFID tag 100 includes an antenna 104. As used herein, the antenna 104 refers to an RFID antenna for receiving and transmitting radio frequency signals to and from the RFID tag. In some embodiments, the antenna 104 is a UHF RFID antenna configured to operate at a resonant frequency in the UHF range. The antenna is also configured to operate at an acceptable operating resonant frequency according to the UHF range variations defined, for example, by ETSI (Europe), i.e., 860-875 MHz, and FCC (US), i.e., 890-930 MHz.

[0030] According to an embodiment, the antenna 104 includes a first dipole antenna 106 having a first notched groove 108 and a second dipole antenna 110 having a second notched groove 112. As used herein, a dipole antenna is a receiver and radiator that operates at UHF. In an embodiment, the first dipole antenna 106 and the second dipole antenna 110 are substantially identical to one another. In some embodiments, the first dipole antenna 106 and the second dipole antenna 110 are serpentine-shaped antennas fabricated using a metal sheet (e.g., aluminum sheet), foil, or other conductive material (e.g., conductive ink). In embodiments in which the antenna 104 is formed from a metal sheet or foil, the first notched groove 108 and the second notched groove 112 can be formed by removing material from the first dipole antenna 106 and the second dipole antenna 110, for example, by an etching or die-cutting process. In an alternative embodiment, the antenna 104 may be formed by printing a conductive ink onto the substrate 102, where the first dipole antenna 106, the first notched groove 108, the second dipole antenna 110, and the second notched groove 112 are all formed by the printing process. Further, in an embodiment, the first notched groove 108 and the second notched groove 112 comprise a substantially rectangular shape. The first notched groove 108 and the second notched groove 112 are provided to assist in impedance matching of the antenna 104 in response to an input frequency.

[0031] In embodiments, the antenna 104 also includes a first loop antenna 114 and a second loop antenna 116 disposed within a central region 118 of the antenna 104. The first loop antenna 114 and the second loop antenna 116 form a closed loop antenna of the antenna 104. As used herein, the central region 118 refers to a central portion of the antenna 104 that extends horizontally from the center of the left side of the antenna 104 to the center of the right side of the antenna 104 and vertically from the center of the top of the antenna 104 to the center of the bottom of the antenna 104. Furthermore, in embodiments, the first loop antenna 114 and the second loop antenna 116 each form a curved rectangular shape. In some embodiments, the first loop antenna 114 includes a first elongated slot, and the second loop antenna 116 includes a second elongated slot. The first loop antenna 114 and the second loop antenna 116 also aid in impedance matching of the antenna 104 in response to input frequencies. In some embodiments, antenna 104, including first loop antenna 114, second loop antenna 116, first dipole antenna 106, and second dipole antenna 110, is formed of a single conductive material (i.e., as opposed to being composed of multiple conductive materials electrically connected to each other, as in other embodiments). According to embodiments, first loop antenna 114 is coupled to first dipole antenna 106 via a first coupling region 126, and second loop antenna 116 is coupled to second dipole antenna 110 via a second coupling region 128. As used herein, coupling region refers to a conductive region formed at the junction between first loop antenna 114 and first dipole antenna 106, and at the junction between second loop antenna 116 and second dipole antenna 110.

[0032] Since the wideband non-folding on-metal UHF RFID tag 100 is an inductive circuit, the resonant frequency is JPEG2025534006000002.jpg1648 This is achieved by: where f0 is the resonant frequency, L is the inductive reactance, and C is the capacitive reactance.

[0033] Therefore, impedance matching is achieved by varying the inductive reactance and capacitive reactance. Additionally, the antenna 104 is tuned to match the frequency of the input signal with the inductive reactance of the antenna 104 to re-radiate the output signal. Furthermore, impedance matching is configured in the antenna 104 by adjusting the lengths of the first notched groove 108 and the second notched groove 112 and / or by adjusting the lengths of the first loop antenna 114 and the second loop antenna 116. In various embodiments, impedance matching is also achieved by varying the lengths of the first coupling region 126 and the second coupling region 128.

[0034] In some embodiments, the wideband, non-folding, on-metal UHF RFID tag 100 includes an RFID chip 120 substantially embedded in the center 122 of the central region 118 of the antenna 104. As used herein, the RFID chip 120 is a microchip and integrated circuit configured to transmit data under the influence of a radio frequency signal. In some embodiments, the UHF RFID tag 100 is a passive RFID tag that activates and draws power from an input signal at a resonant frequency. In various embodiments, the RFID chip 120 can include different resistances depending on the configuration. At the resonant frequency, the cumulative inductive reactance of the antenna 104 and the RFID chip 120 contributes to impedance matching of the input RF signal. In such a case, the input RF signal triggers the RFID chip 120 to transmit data.

[0035] In some embodiments, the first dipole antenna and the second dipole antenna are tuned to resonate at a first resonant frequency. According to an embodiment, the first dipole antenna and the second dipole antenna are tuned to have dipole resonance at a resonant frequency in a UHF frequency range, such as 910 MHz to 960 MHz. In other embodiments, the first loop antenna, the second loop antenna, and the RFID chip are tuned to have loop resonance at a second resonant frequency. According to an embodiment, the first loop antenna, the second loop antenna, and the RFID chip are tuned to have loop resonance at a resonant frequency in a UHF frequency range, such as 820 MHz to 870 MHz.

[0036] According to an embodiment, the wideband non-folding on-metal UHF RFID tag 100 includes a dielectric substrate 124 adhered to the underside of the antenna 104 and the RFID chip 120. In an example, the dielectric substrate 124 is adhesively attached to the underside of the antenna 104 and the RFID chip 120. The dielectric substrate is further attached to the substrate 102. The wideband non-folding on-metal UHF RFID tag 100 is attached to a metal surface adhesive for securing it to the metal surface of a target item. The dielectric substrate 124 generates a potential difference therein to prevent a short circuit between the wideband non-folding on-metal UHF RFID tag 100 and the metal surface when the wideband non-folding on-metal UHF RFID tag 100 is exposed to an input RF signal. In some embodiments, the dielectric substrate is a 1.3 mm thick foam.

[0037] 2 is a graph 200 illustrating a comparison of the resonant frequency and read range of a wideband, non-folding, on-metal UHF RFID tag 100 and a conventional tag, according to an embodiment. As shown, line 202 illustrates the resonant frequency of the conventional tag at 910 MHz and 1.2 GHz (away from the coverage range), while line 204 illustrates the resonant frequency of the wideband, non-folding, on-metal UHF RFID tag 100 at both 860 MHz and 930 MHz within the coverage range. Additionally, line 206 illustrates the read range of the conventional tag, i.e., approximately 4.5 meters. Meanwhile, line 208 illustrates the read range of the wideband, non-folding, on-metal UHF RFID tag 100, i.e., approximately 9 meters.

[0038] 3 is an illustration of a graphical representation of a graph 300 illustrating the resonant frequency of wideband, non-folding, on-metal UHF RFID tag 100 for various widths of the coupling region, according to an embodiment. Thus, graph 300 illustrates the effect of the coupling region on the impedance matching and resonant frequency of wideband, non-folding, on-metal UHF RFID tag 100.

[0039] 4A is an illustration of wideband, non-folding, on-metal UHF RFID tags 402 and 404 for various lengths of loop antennas as a function of the inductive reactance loads of RFID chips 406 and 408, according to an embodiment. As shown herein, wideband, non-folding, on-metal UHF RFID tags 402 and 404 include RFID chips 406 and 408 with capacitive loads of 0.85 pF and 1.5 pF, respectively. Thus, wideband, non-folding, on-metal UHF RFID tag 402 includes a longer length of loop antenna, and wideband, non-folding, on-metal UHF RFID tag 404 includes a shorter length of loop antenna. FIG. 4B shows a graph 410 illustrating the resonant frequencies of wideband, non-folding, on-metal UHF RFID tags 402 and 404 for various lengths of loop antennas as a function of the inductive reactance loads of RFID chips 406 and 408, according to an embodiment of the present invention. Graph 410 shows the resonant frequency for line 412 of wideband non-folding on-metal UHF RFID tag 402 and line 414 of wideband non-folding on-metal UHF RFID tag 404 .

[0040] FIG. 5A is an illustration of a wideband non-folding on-metal UHF RFID tag 500 including a notched groove 502 with a notched width 504, according to an embodiment. Additionally, the wideband non-folding on-metal UHF RFID tag 500 may be configured with a resonant frequency that is substantially determined by the notched width 504 of the wideband non-folding on-metal UHF RFID tag 500. FIG. 5B is an illustration of a graph 506 showing the resonant frequency of the wideband non-folding on-metal UHF RFID tag 500 based on different notched widths 504 of the notched groove 502, according to an embodiment. As shown in FIG. 5B, a line 508 shows the resonant frequency of the wideband non-folding on-metal UHF RFID tag 500 having a notched width 504 of 19 mm operating in the UHF range when exposed to an RF signal. Similarly, graph 506 also shows line 510 corresponding to a 21 mm notch width 504, line 510 corresponding to a 21 mm notch width 504, line 512 corresponding to a 23 mm notch width 504, line 514 corresponding to a 25 mm notch width 504, and line 516 corresponding to a 27 mm notch width 504. As shown in FIG. 5B, graph 506 illustrates the change in read range as the notch width 504 of notch groove 502 is changed.

[0041] FIG. 5C is an illustration of a wideband non-folding on-metal UHF RFID tag 500 including a notched groove 502 with a notched depth 518, according to an embodiment. Additionally, the wideband non-folding on-metal UHF RFID tag 500 may be configured with a resonant frequency that is substantially determined by the notched depth 518 of the wideband non-folding on-metal UHF RFID tag 500. FIG. 5D is an illustration of a graph 520 showing the resonant frequency of the wideband non-folding on-metal UHF RFID tag 500 based on different notched depths 518 of the notched groove 502, according to an embodiment of the present invention. As shown in FIG. 5D , a line 508 shows the resonant frequency of the wideband non-folding on-metal UHF RFID tag 500 having a notched depth 518 of 9 mm operating in the UHF range when exposed to an RF signal. Similarly, graph 520 also shows line 522 corresponding to a 9.5 mm notch depth 518, line 524 for a 10 mm notch depth 518, and line 526 for a 10.5 mm notch depth 518. As shown in FIG. 5D, graph 520 shows the change in read range as the notch depth 518 of notch groove 502 changes.

[0042] FIG. 5E is an illustration of a wideband non-folding on-metal UHF RFID tag 500 including a loop 530 having a loop width 532, according to an embodiment. Additionally, the wideband non-folding on-metal UHF RFID tag 500 may be configured with a resonant frequency that is substantially determined by the loop width 532 of the loop 530 of the wideband non-folding on-metal UHF RFID tag 500. FIG. 5F is an illustration of a graph 534 showing the resonant frequency of the wideband non-folding on-metal UHF RFID tag 500 based on different loop widths 532 of the loop 530, according to an embodiment. As shown in FIG. 5F, a line 536 shows the resonant frequency of the wideband non-folding on-metal UHF RFID tag 500 having a notched loop width 532 of 40 mm operating in the UHF range when exposed to an RF signal. Similarly, graph 534 also shows line 538 at 42 mm loop width 532, line 540 at 44 mm loop width 532, line 542 at 46 mm loop width 532, and line 540 at 48 mm loop width 532. As shown in FIG. 5D , graph 520 illustrates the change in read range as a function of the change in loop width 532 of loop 530 of wideband non-folding on-metal UHF RFID tag 500.

[0043] 6, there is illustrated a flowchart of a method 600 of operation of a wideband non-folding on-metal UHF RFID tag, according to an embodiment.

[0044] In step 602, an input signal is received by the antenna of a wideband, non-folding, on-metal UHF RFID tag at a predefined frequency. The input signal is generated by an RFID reader at the predefined frequency. The predefined frequency may be, for example, 860 MHz or 930 MHz, and transmitted within range of the antenna of the wideband, non-folding, on-metal UHF RFID tag.

[0045] In step 604, the received input signal is transmitted to an RFID chip of the wideband non-folding on-metal UHF RFID tag via an antenna. The antenna is configured to receive the input signal, which travels via a first dipole antenna to a first loop antenna, a second dipole antenna to a second loop antenna, and then to the RFID chip. The input signal travels via the first dipole antenna to the first loop antenna to the RFID chip, and then via the second dipole antenna to the second loop antenna to the RFID chip.

[0046] In step 606, in response to the received input signal, the RFID chip is triggered to resonate at least two resonant frequencies that are matched one at a time.

[0047] The output signal is retransmitted from the RFID chip to the antenna in step 608. The RFID chip is triggered by the input signal and the output signal with the data is retransmitted from the RFID chip to the antenna.

[0048] In step 610, the output signal is radiated through the antenna. The output signal is then simulated through the antenna, and the inductive reactance of the RFID tag re-radiates the output signal by matching the frequency of the received input signal with the inductive reactance of the antenna. The RFID tag is configured to implement impedance matching to match the inductive reactance of the antenna with the frequency of the received input signal, for example, at 860 MHz and 930 MHz.

[0049] Steps 602-610 are merely exemplary, and other alternatives may be provided in which one or more steps are added, one or more steps are deleted, or one or more steps are provided in a different order without departing from the scope of the claims herein.

[0050] 7, there is illustrated a flowchart of a method 700 for manufacturing a wideband non-folding on-metal UHF RFID tag, according to an embodiment.

[0051] In step 702, a single metal sheet, such as an aluminum sheet or foil, is cut to form an antenna. The metal sheet is cut using any conventional antenna cutting method or technique, such as die cutting, laser cutting, etching, etc.

[0052] In step 704, a first dipole antenna is formed in a first notched groove from the antenna, and a second dipole antenna is formed in a second notched groove.

[0053] In step 706, a first loop antenna and a second loop antenna are formed within a central region of the formed antenna.

[0054] Steps 702-706 are merely exemplary, and other alternatives may be provided in which one or more steps are added, one or more steps are removed, or one or more steps are provided in a different order without departing from the scope of the claims herein.

[0055] In some embodiments, the method 700 also includes incorporating an RFID chip in the center of the central region of the antenna, and the RFID chip may be configured with the antenna to provide an inductive reactance for impedance matching when exposed to an RF signal.

[0056] In some embodiments, impedance matching to a predefined resonant frequency is configured in the antenna by adjusting, for example, the length of the first and second notched grooves, the depth of the first and second notched grooves, the length of the first and second loop antennas, and / or the load reactance of the RFID chip.

[0057] In some embodiments, the impedance matching to a predefined resonant frequency is adjusted by the thickness of a dielectric substrate adhesively attached to the underside of the antenna and RFID chip, the dielectric substrate being configured or selected for impedance matching to the predefined resonant frequency, and the dielectric constant being adjusted when tuning the antenna and RFID chip.

[0058] Modifications can be made to the embodiments of the invention described above without departing from the scope of the invention, which is defined by the appended claims. Words such as "including," "comprising," "incorporating," "have," and "is," used to describe and claim the invention, are intended to be interpreted in a non-exclusive manner, allowing for the presence of items, components, or elements not expressly described. References to the singular should also be construed as relating to the plural.

Claims

1. a first dipole antenna having a first notched groove; a second dipole antenna having a second notched groove; an antenna including a first loop antenna and a second loop antenna disposed within a central region of the antenna; and an RFID chip embedded in the center of the central region of the antenna.

2. The broadband non-folding on-metal UHF RFID tag of claim 1 , wherein the first notched groove and the second notched groove are rectangular.

3. 2. The wideband non-folding on-metal UHF RFID tag of claim 1, wherein the first dipole antenna and the second dipole antenna are identical to each other.

4. 2. The wideband non-folding on-metal UHF RFID tag of claim 1, wherein the first loop antenna, the second loop antenna, the first dipole antenna, and the second dipole antenna are formed from a single conductive material.

5. 2. The wideband non-folding on-metal UHF RFID tag of claim 1, wherein the first loop antenna is coupled to the first dipole antenna via a first coupling region, and the second loop antenna is coupled to the second dipole antenna via a second coupling region.

6. The wideband non-folding on-metal UHF RFID tag of claim 1 , wherein the first loop antenna and the second loop antenna form a curved rectangular shape.

7. 10. The broadband non-folding on-metal UHF RFID tag of claim 1, wherein the first loop antenna includes a first elongated slot and the second loop antenna includes a second elongated slot.

8. 2. The wideband non-folding on-metal UHF RFID tag of claim 1, wherein the first dipole antenna and the second dipole antenna are tuned to resonate at a first resonant frequency, and the first loop antenna, the second loop antenna, and the RFID chip are tuned to resonate at a second resonant frequency.

9. 10. The wideband non-folding on-metal UHF RFID tag of claim 1, wherein the dielectric substrate is a foam having a thickness of 1.3 mm.

10. The broadband non-foldable on-metal UHF RFID tag of claim 1 further comprising a dielectric substrate adhered to a bottom surface of said antenna and said RFID chip.

11. receiving an input RF signal via an antenna of a wideband non-folding on-metal UHF RFID tag; transmitting the received input signal via the antenna to an RFID chip of the wideband non-folding on-metal UHF RFID tag; triggering the RFID chip to resonate at at least one of two matched resonant frequencies, one at a time, in response to the received input signal; retransmitting an output signal from the RFID chip to the antenna; radiating said output signal through said antenna.

12. The method of claim 10 , wherein the input signal is generated by one or more RFID readers each operating at a plurality of frequencies exposed to RF signals transmitted from the RFID readers.

13. The method of claim 10 , wherein the antenna is configured to resonate at multiple resonant frequencies in the UHF range.

14. 11. The method of claim 10, wherein the input signal is transmitted to the RFID chip via a first dipole antenna through a first loop antenna and via a second dipole antenna through a second loop antenna.

15. 11. The method of claim 10, wherein the response to the received signal is through the antenna by matching the frequency of the received input signal with the inductive reactance of the antenna such that the inductive reactance of the RFID tag re-radiates the output signal.

16. The method of claim 10 , wherein the output signal comprises data obtained from the RFID chip.

17. cutting a metal sheet to form an antenna; forming a first dipole antenna having a first notched groove and a second dipole antenna having a second notched groove from the antenna; forming a first loop antenna and a second loop antenna within a central region of said antenna.

18. 17. The method of claim 16, further comprising embedding an RFID chip in the center of a central region of the antenna.

19. 20. The method of claim 17, further comprising configuring the RFID chip for impedance matching at a resonant frequency when exposed to an RF signal.

20. The impedance matching for a predefined resonant frequency is the lengths of the first notched groove and the second notched groove; the depth of the first notched groove and the second notched groove; The length of the first loop antenna and the second loop antenna, or 20. The method of claim 18, wherein the load reactance of the RFID chip is adjusted and configured to the antenna.

21. 20. The method of claim 19, wherein impedance matching to a predefined resonant frequency is adjusted by the thickness of a dielectric substrate bonded to the underside of the antenna and the RFID chip.

22. 17. The method of claim 16, wherein the first loop antenna, the second loop antenna, the first dipole antenna, and the second dipole antenna are formed from a single conductive material.

23. 17. The method of claim 16, wherein the first loop antenna is coupled to the first dipole antenna via a first coupling region and the second loop antenna is coupled to the second dipole antenna via a second coupling region.

24. 17. The method of claim 16, wherein the first loop antenna includes a first elongated slot and the second loop antenna includes a second elongated slot.

25. 17. The method of claim 16, wherein the metal sheet is an aluminum sheet.

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