RFID integration into an adaptable substrate assembly

Abstract

A radio-frequency identification (RFID) tag can include an RFID module, a dielectric core, and an antenna structure operably coupled with the RFID module. The antenna structure can comprise a conducting surface comprising conductive material located at least partially over a first surface of the dielectric core and an absence in the conducting surface. The absence is defined by a lack of conductive material on the dielectric core and can be configured to modify one or more electromagnetic properties of the RFID tag. A slot, defined by a gap connected to the absence, is present in the conducting surface. The antenna structure can include first and second ground planes connected to the conducting surface, located on portions of a second surface opposite the first.

Description

RFID INTEGRATION INTO AN ADAPTABLE SUBSTRATE ASSEMBLYCROSS-REFERENCE TO RELATED APPLICATION S)

[0001] This application claims priority to U.S. Prov. Appl. No. 63 / 696,905, titled “RFID Integration into an Adaptable Substrate Assembly,” filed September 20, 2024, which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to Radio Frequency Identification (RFID) tags. Specifically, the present disclosure relates to an RFID tag integrated into an adaptable sub strate / di electric core.BACKGROUND

[0003] RFID tags are a type of tracking system to identify or track items. RFID tags are generally made of an RFID chip (e.g., an integrated circuit), an antenna, and a substrate. The antenna (also called a tag antenna) is connected to the RFID chip and receives signals from an RFID reader (also called an interrogator antenna). Depending on the type of the tag, the tag antenna either transmits or reflects the signal received from the RFID reader. The substrate is a material on which the RFID chip and the tag antenna are mounted. Substrate materials can include paper, polyester, polyethylene, and polycarbonate, for example. RFID tags can be active, passive, or semi-passive. Active tags have a power-source such as a battery on or connected to the tag while passive tags obtain power from radio energy radiated by the interrogator antenna. Semi-passive tags obtain power from the energy radiated by the interrogator antenna and include a battery, for example, to extend the communication range.SUMMARY

[0004] An RFID tag may include a dielectric core with a top surface and a bottom surface. The RFID tag may further include an antenna structure operably coupled with the RFID module. The antenna structure may include a conducting plane located at least partially over the top surface (a first surface) of the dielectric core. The conducting plane may comprise conductive material and include an absence, defined by a lack of the conductive material, configured to modify one or more electromagnetic properties of the RFID tag. Additionally, a slot may be defined by a gap in the conducting plane connected with the absence.

[0005] The antenna structure may also include a first ground plane. The antenna structure may also include a second ground plane. The first ground plane may be connected with the conducting plane and located on a first portion of the bottom surface (a second surface) of the dielectric core opposite the top surface. Similarly, the second ground plane may be connected with the conducting plane and located on a second portion of the bottom surface of the dielectric core. The first and second ground planes may be laterally spaced apart and configured to at least partially overlap to select one or more performance parameters of the antenna structure.

[0006] The RFID module within the RFID tag may be inductively coupled to the antenna structure. This coupling may allow for energy transfer between the RFID module and the antenna structure without a direct physical electrical connection. The RFID module may include a metal lead frame integrated with an ultra-high frequency (UHF) antenna, enhancing the tag's performance capabilities.

[0007] A method of manufacturing the RFID tag may include assembling the antenna structure by forming the conducting plane on the dielectric core, defining the absence and the slot, and positioning the first ground plane and any second ground plane as described above. The method may further involve operably coupling the RFID module with the antenna structure to achieve the desired electromagnetic characteristics and performance parameters.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0009] FIG. 1 A illustrates a view of a top side of an example of a radio-frequency identification (RFID) tag.

[0010] FIG. IB illustrates a view of a bottom side of the RFID tag of FIG. 1 A.

[0011] FIG. 1C illustrates a view from a side of the RFID tag of FIG. 1A.

[0012] FIG. ID illustrates a perspective view of the RFID tag of FIG. 1 A.

[0013] FIGS. IE and IF illustrate an alternate example of a perspective view of an RFID tag showing vertical strips connecting a conductive surface to ground planes.

[0014] FIG. 2 illustrates an example of an RFID module usable with the RFID tag of FIG. 1A.

[0015] FIG. 3 illustrates a side cross-sectional view of the RFID tag of FIG. 1 A with possible mounting positions for the RFID module.

[0016] FIG. 4 illustrates a view of a top of the RFID tag showing the RFID module of FIG. 1 A overlapping a portion of the conducting plane.

[0017] FIG. 5 illustrates an example of a method of fabricating an RFID tag.DETAILED DESCRIPTION

[0018] RFID tags are widely utilized for various applications such as inventory management, asset tracking, and access control. These tags can be either active, incorporating a power source like a battery, or passive, which operate without an external power source. Passive RFID tags are particularly valued in applications like global supply chain management due to their simplicity and cost-effectiveness. However, traditional passive RFID tags often rely on uneconomical dielectric materials and large antennas, which can complicate their structure and increase both size and cost. Additionally, these conventional tags may use discrete radio frequency (RF) components to achieve antenna matching, further complicating the design and increasing the weight. There is, therefore, a need for an RFID tag that employs a simpler, more efficient antenna structure that is smaller, lighter, and less costly to manufacture.

[0019] The present disclosure relates to an RFID tag designed to address these challenges by incorporating an antenna structure that simplifies assembly and reduces material costs. The RFID tag can include a dielectric core and a conducting plane located on a top surface of the dielectric core. The conducting plane can include features such as an absence and a slot in the conducting plane, which are specifically configured to modify electromagnetic properties of the antenna structure and improve performance. This structure allows for enhanced tuning and operational efficiency in various frequency bands, including the UHF band used in some RFID systems.

[0020] The antenna structure of the RFID tag may further include first and second ground planes located on a bottom surface of the dielectric core. These ground planes are designed to partially overlap, which can be adjusted to optimize the tag's performance parameters such as read range and bandwidth. This overlapping feature not only simplifies the antenna's designbut also enhances its effectiveness by reducing the fringing phenomenon, where electromagnetic waves or signals are lost through the substrate.

[0021] A potential advantage of the present disclosure is the ability of the RFID tag to maintain high performance while being configured in a compact and lightweight form. The use of a conducting plane with an absence and a slot allows for precise tuning of the tag's frequency response, enabling it to operate efficiently in the FCC RFID UHF range (902-928 MHz) and other EPC Gen2 bands used globally. The design also allows for the RFID tag to be less susceptible to environmental factors, thereby extending its usability and durability in various operational contexts. Additionally, the method of manufacturing the RFID tag involves straightforward steps / operations that integrate an RFID module with an antenna structure efficiently, further contributing to cost reduction and scalability in production. This method ensures that the RFID tags produced are not only effective in performance but also economical and suitable for widespread deployment in diverse applications.

[0022] FIG. 1 A illustrates an example of an RFID tag 100. The RFID tag 100 may include an antenna structure 116 with a dielectric core 104 and a conducting plane (conducting surface 102) located on at least a portion of the dielectric core 104 (as discussed below). The dielectric core 104 may be any suitable shape and size and formed from any suitable dielectric material. For example, the dielectric core 104 may be a three-dimensional rectangular substrate or rectangular prism substrate as shown in FIG. 1 A, or the dielectric core may be any other suitable three-dimensional shape. The dielectric core 104 may be formed from any suitable dielectric material or combination of dielectric materials, such as but not limited to, a polycarbonate, foam, high-impact polystyrene (HIPS), or acrylonitrile butadiene styrene (ABS). The size, shape, and / or thickness of the dielectric core 104 may be selected based on any suitable factor(s), such as but not limited to, the type of material from which it is formed, a desired read range or performance of the RFID tag, a desired size and / or shape of a housing for the RFID tag 100, or the like.

[0023] The antenna structure 116 can further include an inlay located between the conducting surface 102 and the dielectric core 104. The inlay can be formed from a Polyethylene Terephthalate (PET), Polyvinyl Chloride (PVC), Polycarbonate (PC), Polyethylene (PE), a doped PE, PETE or any derivative of PE, synthetic paper (e.g., Teslin™) or any other paper substrate, Polydimethylsiloxane (PDMS), cotton / noil, or the like. The inlay may be made of any other suitable materials or combination of materials and may be used to mount, affix, adhere, or the like the conducting surface 102 and / or ground planes (discussed below) to the dielectric core 104. The inlay may include a top surface and abottom surface. The bottom surface of the inlay can include an adhesive, thereby providing the inlay with an adhesive backing allowing the inlay to be affixed to the dielectric core 104. In an example, the conducting surface 102 and / or ground planes (discussed below) may be etched or otherwise affixed or adhered to a top surface of the inlay. The inlay may be a relatively flat or thin structure, as would be appreciated by those of skill in the art. In an example, the inlay (e.g., PET) may have a thickness of 0.0025 mm, 0.05 mm, 0.075 mm, 0.1 mm, or any suitable or desired thickness.

[0024] The conducting surface 102 may be located on at least a portion of a surface (e.g., the top surface) of the dielectric core 104. The conducting surface 102 may be formed by a metal such as steel, aluminum, copper, silver, or the like. The material used to form the conducting surface 102 can depend on the application, requirement, use case, or the like for the RFID tag 100. The material from which the conducting surface 102 is formed may be any type of metal that carries electrical current and has a thickness that lends itself to be stamped, bent, or formed into any shape (e.g., a thickness of between 0.05 mm to 2 mm). An absence 110 or void may be formed in the conducting surface 102, such as at a top surface of the antenna structure 116. The absence 110 may be cut or etched out of or otherwise removed from the conducting surface 102 (e.g., a rectangular or any suitably shaped cut out or window) and exposes a portion of the dielectric core 104 through the conducting surface 102. Thus, the absence 110 may be defined in the conducting surface 102 by a lack of the conductive material on the dielectric core 104. The absence 110 may be configured to modify one or more electromagnetic properties of the RFID tag. Stated differently, the size and location of the absence 110 may be designed to affect an electromagnetic property of the RFID tag such as frequency, signal range, signal intensity, or the like. The absence 110 may also serve as a coupling region for an RFID module 108, allowing for inductive energy transfer between the module and the antenna structure 116 without direct physical electrical connection (e.g., without an Ohmic connection). The size, location, and shape of the absence 110 may be designed to achieve optimal impedance matching with the RFID module 108, thereby maximizing power transfer efficiency and read range.

[0025] The conducting surface 102 may include a slot 106. The slot 106 may be defined as a gap in the conducting surface 102 connected with the absence 110. For example, as illustrated in FIG. 1A, the slot 106 may run or span a portion of the conducting surface 102 from an outer edge of the conducting surface 102 to the absence 110 so as to be oriented perpendicular to the absence 110. The slot 106 may act or function as a radiating element and impedance matching feature. Its length, width, and orientation relative to the absence 110may be determined to tune the antenna’s resonance frequency and bandwidth. Adjusting these parameters allows for fine-tuning the RFID tag’s frequency response, enabling efficient operation across various EPC Gen2 bands (e.g., FCC 902-928 MHz, European 865.5-868.5 MHz, or Japanese 950-956 MHz ranges).

[0026] The slot 106 and the absence 110 may be formed in the conducting surface 102 through a process such as etching, laser cutting, die cutting, or the like the conducting surface 102. Thus, to create the antenna structure 116, the conducting surface 102 (e.g., the conducting material) may be deposited on, attached or adhered to, or the like a top surface of the dielectric core 104. From there, portions of the conducting material may be selectively removed via laser cutting or etching to create the desired or appropriate shape, location, dimensions (e.g., thickness), or the like for the absence 110 and the slot 106. Alternatively, the absence 110 and the slot 106 can be formed in the conducting surface 102 before it is attached or adhered to the dielectric core 104. The absence 110 and the slot 106 may act, function, or operate as electromagnetic tuning elements that modify the antenna’s characteristics (e.g., resonant frequency or impedance characteristics). The absence 110 and the slot 106 may operate in conjunction with each other to create an impedance environment. Their precise dimensions and positioning can be determined to optimize the RFID tag’s performance in specific frequency bands, such as the UHF range, optimize the tag’s range, or the like. Thus, the combined electromagnetic effects of the absence 110 and the slot 106 may create an impedance environment that, when properly designed, may enable the RFID tag 100 to achieve high read ranges while maintaining a compact form factor or size.

[0027] The antenna structure 116 may further include a packaged device or integrated circuit module (IC) or RFID module 108 mounted on a portion of the dielectric core 104 and / or the conducting surface 102. As discussed in more detail below with regard to FIGS. 3 and 4, the RFID module 108 may be mounted on the RFID tag 100 in several ways. For example, the RFID module 108 may be mounted completely on a portion of the surface of the dielectric core 104, such as being located within a portion of the absence 110. In another example, the RFID module 108 may be mounted partially over or on a portion of the conducting surface 102 and partially over or on a portion of the dielectric core 104 accessed through the absence 110. In another example, at least a portion of the RFID module 108 may be at least partially submerged in the dielectric core 104.

[0028] FIG. IB illustrates a view of a bottom side of the antenna structure of FIG. 1 A. As illustrated in FIG. IB, the bottom side of the RFID tag 100 may include one or more ground planes or ground plates. For example, a first ground plane 112 and a second ground plane114. The first ground plane 112 may be connected with the conducting surface 102 and located on a first portion of the bottom surface of the dielectric core 104 opposite the top surface. Similarly, the second ground plane 114 may be connected with the conducting surface 102 and located on a second portion of the bottom surface of the dielectric core 104.

[0029] The first ground plane 112 and the second ground plane 114 may be laterally spaced apart on the bottom surface of the dielectric core 104. However, they may be configured to at least partially overlap to select one or more performance parameters of the RFID tag 100. The degree of overlap between the ground planes can be adjusted to tune the antenna's capacitance and overall performance.

[0030] The first ground plane 112 and the second ground plane 114 may be formed from the same conductive material as the conducting surface 102, such as steel or aluminum, or from a different material than the conducting surface 102. The ground planes may be wrapped around the ends of the antenna structure 116 from the top surface to the bottom surface, creating a continuous conductive path from the conducting surface 102 to the bottom of the dielectric core 104.

[0031] The configuration of the ground planes, including their size, shape, and degree of overlap, affect the electromagnetic characteristics of the RFID tag 100. By adjusting these parameters, the tag's frequency response can be fine-tuned for specific operational requirements and frequency bands. For example, a longer overlap between the ground planes generally corresponds to a lower frequency response, while a shorter overlap or no overlap may result in higher frequency performance. The presence of these ground planes may help to reduce the fringing phenomenon, where electromagnetic waves or signals are lost through the substrate. This enhances the overall efficiency and performance of the RFID tag.

[0032] In an example, the conducting surface 102, the first ground plane 112 and the second ground plane 114 may be etched on the dielectric core 104, screen printed on the dielectric core 104, attached or adhered to the dielectric core 104, or otherwise joined with or located on the dielectric core 104 via any suitable fabrication method or process. The ground planes 112, 114, the dielectric core 104 and the conducting surface 102 may generally have rectangular cross-sectional shapes as shown in FIG. 1 A, but it is understood that any suitable cross-sectional shape (e.g., square, circular, polygonal, or the like) may be used for any of the dielectric core, the conducting surface, or the ground planes.

[0033] Furthermore, though not required, the first ground plane 112 and the second ground plane 114 may be a similar shape and size to one another and may be arranged so that one of the ground planes at least partially overlaps with the other ground plane. Alternatively, theground planes may be arranged to be substantially symmetrical on the bottom surface of the dielectric core 104. For example, an edge of the first ground plane 112 may abut, touch, but not overlap, an edge of the second ground plane 114 in substantially the middle, center, or the like of the bottom surface of the dielectric core 104. In another example, the ground planes may be arranged so that a gap is formed between an edge of the first ground plane 112 and the second ground planes 112, 114.

[0034] As noted above, the first ground plane 112 and the second ground plane 114 may be configured to provide flexibility in tuning the performance of the RFID tag 100 and / or the antenna structure 116. By adjusting the degree of overlap between these ground planes, the capacitance of the RFID tag 100 can be fine-tuned, allowing for optimization of the tag's performance in specific frequency bands or operational environments. This adjustable overlap feature may enable the RFID tag to be adapted for various applications without necessitating changes to other components of the RFID tag 100 and / or the antenna structure 116.

[0035] Wrapping of the ground planes 112, 114 around the ends of the RFID tag 100 or the antenna structure 116 from the top surface to the bottom surface of the dielectric core 104 may create or establish a continuous conductive path and may contribute to the overall durability and robustness of the RFID tag 100 and / or the antenna structure 116. This design feature may help to protect the edges of the dielectric core 104 and may provide additional structural integrity to the tag, potentially enhancing its resistance to environmental factors and physical stress.In an example, the conductive surface 102 and the ground planes 112, 114 can be formed from a single piece of material the can be wrapped around the ends of the RFID tag 100. In another example, as illustrated in FIGS. IE and IF, a connecting strip can be used to connect the conductive surface 102 to the ground planes 112, 114. FIGS. IE and IF illustrate an alternate example of a perspective view of an RFID tag showing connecting strips connecting a conductive surface to ground planes. For example, as shown in FIG. IE, a first (vertical) connecting strip 118 can connect the conducting surface 102 to the second ground plane 114. Similarly, as shown in FIG. IF, a second (vertical) connecting strip 120 can connect the conducting surface 102 to the first conductive strip 112. In an example, the connecting strips 118, 120, can be formed from the same piece of material as the conducting surface 102 and / or the ground planes 112, 114 or they can be separate material pieces formed from the same or a different material than either the conducting surface 102 or the ground planes 112, 114. Further, the connecting strips 118, 120 can have any dimension (e.g., any suitable length orwidth between the conducting surface 102 and respective ground planes 112, 114) and can be positioned along any portion along the length of the side edges (e.g., in the middle, biased toward one end or the other) as desired or appropriate for a particular application or use case. In some examples, if the overall size of the tag is fixed, and further tuning is required, the connecting strips 118, 120 can be used to tune the peak frequency response of the tag at both ends. The dimensions and locations of the each connecting strip can be varied depending on the desired peak frequency response.

[0036] While the ground planes 112, 114 are described as being located on the bottom surface of the dielectric core 104, it should be noted that their positioning relative to the RFID module 108 may affect the tag's performance. An example arrangement may involve positioning the ground planes 112, 114 such that they do not significantly interfere with the coupling between the RFID module 108 and the absence 110 in the conducting surface 102. This careful positioning can help to maintain efficient energy transfer between the RFID module 108 and the antenna structure 116. Thus, the ability to adjust the size, shape, and overlap of the ground planes 112, 114 may help optimize the RFID tag's performance without necessarily altering the dimensions of the dielectric core 104 or the conducting surface 102. This feature allows for fine-tuning of the tag's electromagnetic characteristics while maintaining a consistent overall form factor, which can be advantageous in applications where size constraints are necessary or desired.

[0037] In sum, the absence 110, slot 106, and ground planes 112, 114 work together in a complex interplay to control the RFID tag's electromagnetic properties:

[0038] The absence 110 in the conducting surface 102 may act, function, or operate as a coupling region for the RFID module 108, allowing for inductive or similar energy transfer between the RFID module and the antenna structure 116 without direct physical electrical connection. Its size and shape may be carefully designed to achieve optimal impedance matching with the RFID module 108, maximizing or optimizing power transfer efficiency and read range.

[0039] The slot 106 may serve as both a radiating element and an impedance matching structure. It can help to disconnect negative and positive current, and its length, width, and position relative to the absence 110 can be adjusted to tune the resonant frequency and bandwidth of the RFID tag 100 and / or the antenna structure 116. Shifting the slot's 106 position can adjust the frequency response of the RFID tag 100 and / or the antenna structure 116 up or down.

[0040] The ground planes 112, 114 on the bottom surface of the dielectric core 104 provide additional tuning capabilities. Their size, shape, and degree of overlap can be adjusted to fine-tune the capacitance and overall performance of the RFID tag 100. A longer overlap between the ground planes 112, 114 generally corresponds to a lower frequency response, while a shorter overlap or no overlap may result in higher frequency performance.

[0041] FIG. 1C illustrates a side view of the RFID tag 100 of FIG. 1 A. From this perspective, the layered configuration of the RFID tag 100 is visible. The dielectric core 104 forms the base layer, with the conducting surface 102 positioned on its top surface. The RFID module 108 is shown mounted on the RFID tag 100. The conducting surface 102 is depicted as a thin layer atop the dielectric core 104, illustrating its placement on at least a portion of the top surface of the dielectric core 104. The thickness of the conducting surface 102 may vary depending on the specific metal used and manufacturing requirements, typically ranging from 0.05 mm to 2 mm.

[0042] The RFID module 108 is shown positioned relative to the conducting surface 102 and the dielectric core 104. This side view illustrates how the RFID module 108 may be mounted in just one of various configurations. For example, it may be mounted completely on a portion of the surface of the dielectric core 104 (as shown in FIG. 1 C), partially over the conducting surface 102 and partially over the dielectric core 104 (as shown in FIG. 4), or partially submerged in the dielectric core 104 (as shown in FIG. 3).

[0043] The side view also demonstrates how the ground planes 112, 114 can wrap around the ends of the RFID tag 100 from the top surface to the bottom surface, creating a continuous conductive path from the conducting surface 102 to the bottom of the dielectric core 104. This side view emphasizes the compact nature of the RFID tag 100, showcasing how the various elements are integrated to form a thin, lightweight RFID tag suitable for a wide range of applications.

[0044] FIG. ID illustrates a perspective view of the RFID tag of FIG. 1 A. This three- dimensional view provides a comprehensive look at the various components of the RFID tag 100, illustrating an example of their spatial relationships. The dielectric core 104 forms the base of the structure, with the conducting surface 102 visible on its top face. The slot 106 can be clearly seen as a narrow gap in the conducting surface, extending from an edge to the absence 110. The RFID module 108 is positioned within the absence 110, demonstrating its placement relative to the other elements of the antenna structure 116.

[0045] FIG. 2 illustrates an example of an RFID integrated circuit (IC) module 108 that can be used in the RFID tag of FIG. 1A. The RFID module 108 comprises an RFID chip 202connected to a primary antenna structure 204. The RFID chip 202 is shown here, for example, as a small rectangular element at the center of an edge of the module. This chip contains the integrated circuitry necessary for RFID functionality, including memory for storing identification data and processing capabilities for communication.

[0046] The primary antenna structure 204 may be a coupling element that extends from and / or generally surrounds the RFID chip 202 and is formed from a metal lead frame. This lead frame serves a dual purpose - it provides mechanical support for the RFID chip and functions as an antenna for near-field communication. The primary antenna structure 204 can include two or more nested loops, creating a compact and efficient design.

[0047] Wire bonds 206, 208, and 210 may help in tuning the antenna's performance. Their precise placement can affect the effective area and inductance of the antenna loop, allowing for fine adjustment of the module's resonant frequency. This tuning capability enables the module to be optimized for different RFID chips and operational requirements. A nonlimiting example of an RFID module compatible with the RFID tag 100 of the present disclosure is described in US Patent 9,626,617 B2, which is incorporated herein by reference in its entirety.

[0048] The RFID module 108 may be designed to operate as a near-field device, achieving a read range of about 0.5 to 1 meter on its own. However, when coupled with the larger RFID tag 100 described in FIG. 1 A, the read range can be significantly enhanced. The entire RFID module 108 may be encapsulated in a protective material, forming a small, durable package. This encapsulation protects the delicate components from environmental factors and physical stress, contributing to the long-term durability of the RFID tag.

[0049] When integrated with the antenna structure 116 of FIG. 1 A, the RFID module 108 may be positioned within or adjacent to the absence 110 (e.g., partially overlapping the absence 110 and the conducting surface 102) in the conducting surface 102 (as shown in FIG. 1 A). The RFID module 108 may be located on the surface of the dielectric core 104 or the conducting surface or may be at least partially submerged into the dielectric core 104. This positioning allows for inductive coupling between the primary antenna structure 204 of the RFID module and the larger RFID tag 100, enabling efficient energy transfer without direct electrical connection.

[0050] FIG. 3 illustrates a side cross-sectional view of the RFID tag 100 of FIG. 1 A, showing possible mounting positions of the RFID module 108. This view depicts the layered configuration of the RFID tag 100, including the dielectric core 104 and the conductingsurface 102 and demonstrates three potential mounting configurations for the RFID module 108:

[0051] Surface Mounted: In this configuration, the RFID module 108, including an antenna 300A, is positioned on the surface of the dielectric core 104, within the absence 110 of the conducting surface 102.

[0052] Partially Embedded: In this configuration, the RFID module 108 is shown partially submerged into the dielectric core 104. This configuration may provide a balance between coupling efficiency and physical protection for the module. For example, when an antenna 300B of the RFID module 108 is generally at a same level as the conducting surface 102, optimum performance may be achieved in some applications, devices, etc.

[0053] Fully Embedded: In this configuration, the RFID module 108, including an antenna 300C, is mostly or completely embedded within the dielectric core 104. While this configuration offers an increased level of physical protection for the RFID module 108, it may affect the coupling efficiency.

[0054] The positioning of the RFID module 108 relative to the conducting surface 102 and the dielectric core 104 can significantly impact the RFID tag's performance. An optimal arrangement may involve positioning a metal part of the RFID module (e.g., the copper lead frame or antenna 300 A, 300B, 300C) at generally a same level as the conducting surface 102. This alignment may maximize the inductive coupling between the RFID module 108 and the antenna structure 116.

[0055] When the module is fully embedded inside the substrate, the capacitive coupling between the module and the ground plane may increase, potentially reducing performance. Therefore, the thickness of the dielectric core and the depth of embedding may be carefully considered to achieve the desired balance between protection and performance. These various mounting options provide flexibility in the design and manufacturing of the RFID tag, allowing for optimization based on specific application requirements, such as durability needs or performance priorities.

[0056] FIG. 4 illustrates a view of the top of the RFID tag 100 showing the RFID module 108 overlapping a portion of the conducting surfacel02. In this configuration, the RFID module 108 is positioned such that it partially overlaps the conducting surface 102 and partially overlaps the dielectric core 104 in an area of the absence 110. This arrangement demonstrates the flexibility in positioning the RFID module 108 within the antenna structure

[0057] The absence 110 is shown as a rectangular cut-out in the conducting surface 102, exposing a portion of the dielectric core 104. The RFID module 108 is placed such that it bridges this absence 110, with part of it resting on the conducting surface 102 and part on the exposed dielectric core 104. As discussed above, while the dielectric core 104, conducting surface 102, and the absence 110 are shown as having substantially or generally rectangular cross-sections, they can be formed to have any cross-sectional shape desired or appropriate.

[0058] Furthermore, the location of the slot 106 may be varied along the length of the conducting surface 102 as the slot 106 runs from an outer edge of the conducting surface 102 to the absence 110. Two ground planes, such as ground planes 112 and 114 illustrated in FIG. IB, may be overlapped on a bottom surface or bottom side of the dielectric core 104. In an example, one ground plane can partially overlap the other ground plane (as shown in FIG. IB where ground plane 114 partially overlaps ground plane 112). Alternatively, one ground plan may completely overlap the other ground plane. For example, the ground planes may overlap so that one of the ground planes may completely cover (or substantially completely cover) the other ground plane.

[0059] The dielectric core 104 can have any suitable thickness. In an example, the dielectric core 104 may have a thickness between about 1 mm to about 10 mm. The dielectric core 104 may have a length of about 70 mm and a width of about 30 mm. The thickness of the dielectric core 104 may be selected based on any suitable factor(s), such as but not limited to, the type of material from which the core is formed (e.g., a polycarbonate, foam, high- impact polystyrene (HIPS), or acrylonitrile butadiene styrene (ABS)), a desired read range of the RFID tag 100, or the like. In some examples, a thicker substrate can result in an increased read range of the RFID tag 100. It is understood that the dimensions of the dielectric core 104 (e.g., the length, the width, or the thickness) may be adjusted as suitable or desired based, at least in part, on one or more factors such as, but not limited to, desired bandwidth, readrange, or the like of the RFID tag 100 and / or the antenna structure 116.

[0060] This configuration of the RFID module 108 partially overlapping the conducting surface 102 allows for a different coupling mechanism between the module and the antenna structure. While this arrangement may affect the capacitive coupling between the module and the antenna structure, it provides an alternative design option that may be beneficial in certain applications. The precise positioning of the RFID module 108 in this overlapping configuration can be adjusted to fine-tune the performance of the antenna structure 116. The degree of overlap with the conducting surface 102 and the absence 110 may be optimized to achieve the desired balance of coupling efficiency and overall tag and / or antennaperformance. This arrangement demonstrates the versatility of the RFID tag 100 design, allowing for various mounting options of the RFID module 108 to suit different operational requirements or manufacturing constraints.

[0061] FIG. 5 illustrates an example of a method 500 of fabricating an RFID tag. The method 500 can include a number of operations or steps. The steps described are examples only, and the method can omit one or more of the listed steps, can repeat steps, can include other steps, or can execute the steps concurrently, substantially simultaneously, or in another order, as appropriate or desired.

[0062] Step 502 of the method 500 may include forming a conducting plane, comprising conductive material, on a first surface of a dielectric core. The conducting plane may include an absence defined by a lack of the conductive material on the dielectric core and be configured to modify one or more electromagnetic properties of the antenna structure. Additionally, a slot may be defined by a gap in the conducting plane connected with the absence. The width and location of the slot in the conducting surface may be selected to correspond to a desired frequency of the antenna structure. The position of the slot (e.g., shifting it to the right or left) can be used to adjust the antenna's frequency response up or down.

[0063] Step 504 may involve positioning a first ground plane connected with the conducting plane on a first portion of a second surface of the dielectric core opposite the first surface. Similarly, step 506 may include positioning a second ground plane connected with the conducting plane on a second portion of the second surface. In an example, the first ground plane and the second ground plane on the second surface may be configured or designed based on one or more desired electromagnetic characteristics of the antenna structure. This may include adjusting a degree of overlap between the ground planes to tune the capacitance and overall performance of the antenna structure.

[0064] In step 508, an RFID module may be operably coupled with the antenna structure. This coupling may be achieved inductively, without a direct physical electrical connection between the RFID module and the antenna structure. Step 508 may include positioning the RFID module entirely within the area (or a portion of the area) of the absence so that the RFID module is situated, located, or the like entirely on the dielectric core. Step 508 may alternatively include positioning the RFID module to partially overlap the conducting surface and partially overlap the dielectric core in an area of the absence. The positioning of the RFID module can be adjusted to fine-tune the antenna's performance and achieve the desired balance of coupling efficiency and overall tag performance.

[0065] In an example, the conducting plane and ground planes may be formed from a metal such as steel, aluminum, copper, or any suitable metal or alloy that can provide durability and long-term performance. As discussed above, the RFID module may be at least partially encapsulated or submerged in the dielectric core. This can provide protection for the module while maintaining optimal coupling with the antenna structure. Throughout the fabrication process, careful consideration can be given to the interplay between the absence, slot, and ground planes, as their relative positions and dimensions may be optimized to achieve the desired frequency response and read range for the RFID tag.

[0066] Example l is a radio-frequency identification (RFID) tag comprising: an RFID module; a dielectric core; and an antenna structure operably coupled with the RFID module and comprising: a conducting surface, comprising conductive material, located at least partially over a first surface of the dielectric core; an absence defined in the conducting surface by a lack of the conductive material on the dielectric core and configured to modify one or more electromagnetic properties of the RFID tag; a slot defined by a gap in the conducting surface and connected with the absence; a first ground plane connected with the conducting surface and located on a first portion of a second surface of the dielectric core opposite the first surface; and a second ground plane connected with the conducting surface and located on a second portion of the second surface.

[0067] In Example 2, the subject matter of Example 1 optionally includes subject matter wherein the RFID module is inductively coupled with the antenna structure.

[0068] In Example 3, the subject matter of any one or more of Examples 1-2 optionally include subject matter wherein the RFID module is at least partially encapsulated in the dielectric core.

[0069] In Example 4, the subject matter of any one or more of Examples 1-3 optionally include subject matter wherein the RFID module includes a metal lead frame integrated with an ultra-high frequency (UHF) antenna.

[0070] In Example 5, the subject matter of any one or more of Examples 1-4 optionally include subject matter wherein the conductive material is at least one of steel or aluminum.

[0071] In Example 6, the subject matter of any one or more of Examples 1-5 optionally include subject matter wherein a width and location of the slot in the conducting surface corresponds to a selected frequency of the antenna structure.

[0072] In Example 7, the subject matter of any one or more of Examples 1-6 optionally include subject matter wherein the RFID module and the antenna structure are configured toallow for energy transfer between the RFID module and the antenna structure without a direct physical electrical connection.

[0073] In Example 8, the subject matter of any one or more of Examples 1-7 optionally include subject matter wherein the RFID module is magnetically coupled with the antenna structure.

[0074] In Example 9, the subject matter of any one or more of Examples 1-8 optionally include subject matter wherein the RFID module is capacitively coupled with the antenna structure.

[0075] In Example 10, the subject matter of any one or more of Examples 1-9 optionally include subject matter wherein the first ground plane and the second ground plane are laterally spaced apart.

[0076] In Example 11, the subject matter of any one or more of Examples 1-10 optionally include subject matter wherein the first ground plane and the second ground plane at least partially overlap on the second surface of the dielectric core.

[0077] In Example 12, the subject matter of any one or more of Examples 1-11 optionally include subject matter wherein the RFID module is positioned to partially overlap the conducting surface and partially overlap the dielectric core in an area of the absence.

[0078] Example 13 is a method for manufacturing a radio-frequency identification (RFID) tag, the method comprising: assembling an antenna structure by: forming a conducting plane, comprising conductive material, on a first surface of a dielectric core, wherein the conducting plane comprises: an absence defined by a lack of the conductive material on the dielectric core and configured to modify one or more electromagnetic properties of the RFID tag; and a slot defined by a gap in the conductive material and connected with the absence; positioning a first ground plane, connected with the conducting plane, on a first portion of a second surface of the dielectric core opposite the first surface; and positioning a second ground plane, connected with the conducting plane, on a second portion of the second surface; and operably coupling an RFID module with the antenna structure.

[0079] In Example 14, the subject matter of Example 13 optionally includes subject matter wherein forming the conducting plane comprises: depositing the conductive material on the first surface of the dielectric core; and removing portions of the conductive material to create the absence and the slot.

[0080] In Example 15, the subject matter of any one or more of Examples 13-14 optionally include configuring the first ground plane and the second ground plane on the second surface based on one or more desired electromagnetic characteristics of the RFID tag.

[0081] In Example 16, the subject matter of any one or more of Examples 13-15 optionally include inductively coupling the RFID module with the antenna structure.

[0082] Example 17 is a radio-frequency identification (RFID) tag comprising: an encapsulated RFID module including a UHF module integrated with a metal lead frame; and an antenna structure comprising: a dielectric core; a conducting surface, comprising conductive material, located at least partially over a first surface of the dielectric core; an absence defined in the conducting surface by a lack of the conductive material on the dielectric core and configured to modify one or more electromagnetic properties of the RFID tag; a slot defined by a gap in the conducting surface and connected with the absence; a first ground plane connected with the conducting surface and located on a first portion of a second surface of the dielectric core; and a second ground plane connected with the conducting surface and located on a second portion of the second surface; wherein the first ground plane and the second ground plane are configured to at least partially overlap to select one or more performance parameters of the antenna structure; and wherein the RFID module is inductively coupled to the antenna structure.

[0083] In Example 18, the subject matter of Example 17 optionally includes subject matter wherein at least one of a width or a location of the slot in the conducting surface is selected based on one or more predetermined operational requirements of the RFID tag.

[0084] In Example 19, the subject matter of any one or more of Examples 17-18 optionally include subject matter wherein the antenna structure is configured to boost a range of the RFID module, and wherein the conductive material is at least one of steel or aluminum.

[0085] In Example 20, the subject matter of any one or more of Examples 17-19 optionally include subject matter wherein the RFID module is at least partially embedded in the dielectric core.

[0086] In Example 21, the subject matter of any one or more of Examples 17-20 optionally include subject matter wherein the RFID module is positioned to partially overlap the conducting surface and partially overlap dielectric core in an area of the absence.

[0087] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments that may be practiced. These embodiments are also referred to herein as “examples.” Such examples may include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or moreaspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0088] As used herein, the terms “substantially” or “generally” refer to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” or “generally” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking, the nearness of completion will be so as to have generally the same overall result as if absolute and total completion were obtained. The use of “substantially” or “generally” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, an element, combination, embodiment, or composition that is “substantially free of’ or “generally free of’ an element may still actually contain such element as long as there is generally no significant effect thereof.

[0089] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. The scope of the embodiments should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A radio-frequency identification (RFID) tag comprising: an RFID module; a dielectric core; and an antenna structure operably coupled with the RFID module and comprising: a conducting surface, comprising conductive material, located at least partially over a first surface of the dielectric core; an absence defined in the conducting surface by a lack of the conductive material on the dielectric core and configured to modify one or more electromagnetic properties of the RFID tag; a slot defined by a gap in the conducting surface and connected with the absence; and a first ground plane connected with the conducting surface and located on at least a first portion of a second surface of the dielectric core opposite the first surface.

2. The RFID tag of claim 1, wherein the RFID module is inductively coupled with the antenna structure.

3. The RFID tag of claim 1, wherein the RFID module is at least partially encapsulated in the dielectric core.

4. The RFID tag of claim 1, wherein the RFID module includes a metal lead frame integrated with an ultra-high frequency (UHF) antenna.

5. The RFID tag of claim 1, wherein the conductive material is at least one of steel or aluminum.

6. The RFID tag of claim 1, wherein a width and location of the slot in the conducting surface corresponds to a selected frequency of the antenna structure.

7. The RFID tag of claim 1, wherein the RFID module and the antenna structure are configured to allow for energy transfer between the RFID module and the antenna structure without a direct physical electrical connection.

8. The RFID tag of claim 1, wherein the RFID module is magnetically coupled with the antenna structure.

9. The RFID tag of claim 1, wherein the RFID module is capacitively coupled with the antenna structure.

10. The RFID tag of claim 1, further comprising a second ground plane connected with the conducting surface and located on at least a second portion of the second surface.

11. The RFID tag of claim 10, wherein the first ground plane and the second ground plane are laterally spaced apart.

12. The RFID tag of claim 1, wherein the first ground plane and the second ground plane at least partially overlap on the second surface of the dielectric core.

13. The RFID tag of claim 1, wherein the RFID module is positioned to partially overlap the conducting surface and partially overlap the dielectric core in an area of the absence.

14. A method for manufacturing a radio-frequency identification (RFID) tag, the method comprising: assembling an antenna structure by: forming a conducting plane, comprising conductive material, on a first surface of a dielectric core, wherein the conducting plane comprises: an absence defined by a lack of the conductive material on the dielectric core and configured to modify one or more electromagnetic properties of the RFID tag; and a slot defined by a gap in the conductive material and connected with the absence; andpositioning a first ground plane, connected with the conducting plane, on at least a first portion of a second surface of the dielectric core opposite the first surface; and operably coupling an RFID module with the antenna structure.

15. The method of claim 14, wherein forming the conducting plane comprises: depositing the conductive material on the first surface of the dielectric core; and removing portions of the conductive material to create the absence and the slot.

16. The method of claim 14, wherein assembling the antenna structure further comprises positioning a second ground plane, connected with the conducting plane, on at least a second portion of the second surface.

17. The method of claim 16, further comprising configuring the first ground plane and the second ground plane on the second surface based on one or more desired electromagnetic characteristics of the RFID tag.

18. The method of claim 14, further comprising inductively coupling the RFID module with the antenna structure.

19. A radio-frequency identification (RFID) tag comprising: an encapsulated RFID module including a UHF module integrated with a metal lead frame; and an antenna structure comprising: a dielectric core; a conducting surface, comprising conductive material, located at least partially over a first surface of the dielectric core; an absence defined in the conducting surface by a lack of the conductive material on the dielectric core and configured to modify one or more electromagnetic properties of the RFID tag; a slot defined by a gap in the conducting surface and connected with the absence; and a first ground plane connected with the conducting surface and located on at least a first portion of a second surface of the dielectric core;wherein the RFID module is inductively coupled to the antenna structure.

20. The RFID tag of claim 19, wherein at least one of a width or a location of the slot in the conducting surface is selected based on one or more predetermined operational requirements of the RFID tag.

21. The RFID tag of claim 19, wherein the antenna structure is configured to boost a range of the RFID module, and wherein the conductive material is at least one of steel or aluminum.

22. The RFID tag of claim 19, wherein the RFID module is at least partially embedded in the dielectric core.

23. The RFID tag of claim 19, wherein the RFID module is positioned to partially overlap the conducting surface and partially overlap dielectric core in an area of the absence.

24. The RFID tag of claim 19, wherein the antenna structure further comprises a second ground plane connected with the conducting surface and located on at least a second portion of the second surface, wherein the first ground plane and the second ground plane are configured to at least partially overlap to select one or more performance parameters of the antenna structure.

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