阅读说明：本技术 耐受微波炉的操作于高频带中的rfid标签 (RFID tag resistant to operation of microwave oven in high frequency band ) 是由 I·福斯特 于 2019-06-27 设计创作，主要内容包括：一种耐受高场发射的RFID标签装置,其可以固定到要在加热设备(例如但不限于微波炉)中烹饪、加热、再加热和/或解冻的产品上,并且在开始加热过程之前不需要将将从产品移除。RFID装置是微波安全的,在微波过程中不会损坏其被附接到的产品或食品,并且可以包含用于控制微波过程的数据。微波安全的RFID标签包括形成在基板(或电介质)的一侧上的开口环(或屏蔽)导体、形成在基板的相对侧上的线圈天线导体以及RFID芯片。开口环导体通过电介质电容性地耦合至线圈天线导体,并且开口环导体中的间隙防止电弧放电。(An RFID tag device that is resistant to high field emissions, can be affixed to a product to be cooked, heated, reheated and/or thawed in a heating apparatus (such as, but not limited to, a microwave oven), and does not need to be removed from the product prior to beginning the heating process. The RFID device is microwave safe, does not damage the product or food to which it is attached during the microwave process, and may contain data for controlling the microwave process. A microwave-safe RFID tag includes a split ring (or shield) conductor formed on one side of a substrate (or dielectric), a coil antenna conductor formed on the opposite side of the substrate, and an RFID chip. The split ring conductor is capacitively coupled to the coil antenna conductor by a dielectric, and a gap in the split ring conductor prevents arcing.)

1. A Radio Frequency Identification (RFID) tag that is tolerant of high field emissions, comprising:

an RFID chip;

an antenna conductor;

a split ring conductor; and

a dielectric between the antenna conductor and the split ring conductor.

2. The RFID tag of claim 1, wherein the split-ring conductor is capacitively coupled to the antenna conductor.

3. The RFID tag of claim 1, wherein the split ring conductor is formed on a first side of the dielectric and the antenna conductor is formed on an opposite side of the dielectric.

4. The RFID tag of claim 1, wherein the antenna conductor comprises a gap.

5. The RFID tag of claim 4, wherein the RFID chip is located in the gap.

6. The RFID tag of claim 1, wherein the center and outer edges of the antenna conductor bridge together conductive traces forming an inductor.

7. The RFID tag of claim 1, wherein the split ring conductor covers a majority of the antenna conductor.

8. The RFID tag of claim 7, wherein the split ring conductor includes a gap where the antenna conductor is not covered.

9. A Radio Frequency Identification (RFID) tag for use in a heating apparatus, comprising:

an RFID chip;

a coil antenna conductor;

a first split ring conductor; and

a second split ring conductor.

10. The RFID tag of claim 9, wherein the coil antenna conductor is located between the first and second split-ring conductors.

11. The RFID tag of claim 9, wherein the coil antenna conductor is capacitively coupled to the first and second split-ring conductors.

12. The RFID tag of claim 9, wherein the first split ring conductor includes a first gap and the second split ring conductor includes a second gap.

13. The RFID tag of claim 12, wherein the second split ring conductor is rotated relative to the first split ring conductor such that the first gap is not aligned with the second gap.

14. The RFID tag of claim 9, wherein the center and outer edges of the coil antenna conductor bridge together conductive traces forming an inductor.

15. The RFID tag of claim 9, wherein the RFID chip is located in a gap in the coil antenna conductor.

16. A Radio Frequency Identification (RFID) tag for use in a microwave field, comprising:

an RFID chip fixed to the shielding tape;

a coil antenna conductor; and

split ring conductors.

17. The RFID tag of claim 16, wherein the RFID chip and the shielding tape are located on the coil antenna conductor.

18. The RFID tag of claim 17, wherein the split ring conductor is located on top of the RFID chip and the shielding tape.

19. The RFID tag of claim 16, further comprising a resonant circuit.

20. The RFID tag of claim 16, wherein the split-ring conductor is capacitively coupled to the coil antenna conductor.

Background

The present invention relates generally to radio frequency identification ("RFID") tags that can withstand high transmission fields, such as, but not limited to, high transmission fields of microwave ovens, and methods of controlling various aspects of a heating process (e.g., a heating process by microwaves) using RFID tags that are tolerant of high transmission fields. In particular, there is no need to remove the RFID tag from the product or food product before cooking or heating in an apparatus such as a microwave oven. The microwave-safe RFID tag of the present invention prevents the formation of an arc and thus can be placed inside a microwave oven without damaging the product or food to which it is attached. Thus, during high power high field or microwave transmission, the RFID reader system may read or interrogate RFID tags.

The present disclosure focuses on high frequency ("HF") technology operating at 13.56MHz and ultra high frequency ("UHF") technology operating in various bands worldwide including 865-. Therefore, this specification makes specific reference thereto. However, it should be appreciated that aspects of the present subject matter are equally applicable to other similar applications.

In general, radio frequency identification utilizes electromagnetic energy to stimulate a responsive device (referred to as an RFID "tag" or transponder) to identify itself and, in some cases, to provide additional stored data in the tag. RFID tags typically include a semiconductor device, commonly referred to as a "chip," on which is formed a memory and operating circuitry that is connected to an antenna. Typically, RFID tags are used as transponders to provide information stored in a chip memory in response to a radio frequency ("RF") interrogation signal received from a reader (also referred to as an interrogator). In the case of passive RFID devices, the energy of the interrogation signal also provides the energy required to operate the RFID tag device.

RFID tags may be incorporated into or attached to items to be tracked. In some cases, the label may be attached to the exterior of the article by adhesive, tape, or other means, while in other cases the label may be inserted into the article, for example contained in a package, located in a container of the article, or sewn onto a garment. RFID tags are manufactured with a unique identification number, which is typically a simple serial number of a few bytes with check bits. The identification number is incorporated into the tag during manufacture. The user cannot change this serial number/identifier and the manufacturer ensures that each serial number is used only once. Such read-only RFID tags are typically permanently attached to the item to be tracked and, once attached, the serial number of the tag is associated with its host item in a computer database.

Currently, RFID technology implemented in food products to be cooked in a microwave oven does not survive the high field emission of the microwave oven. More specifically, the RFID tag is typically destroyed in the microwave cavity and may also damage the food product to which the RFID tag is attached. Accordingly, there is a need for a microwave-safe RFID tag device that can operate within a microwave oven and that does not damage the food product to which the RFID tag is attached.

A microwave-safe RFID tag is secured to a food or other product to be cooked, heated, reheated and/or thawed in a microwave oven and does not need to be removed from the food or product before the microwave process is restarted. In addition, the RFID tag may be placed inside the microwave oven without damaging the food or product to which the RFID tag is attached and provide data for controlling the cooking process.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed innovation. This summary is not an extensive overview and is not intended to identify key/critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

The subject matter disclosed and claimed herein, in one aspect thereof, comprises a microwave-safe RFID tag device that is secured to a food or other product to be cooked, heated, reheated and/or thawed in a microwave oven. The RFID tag may include various information including, but not limited to, information about the product to which it is attached, the user of the RFID tag, instructions for operation of the microwave oven, and the like.

A microwave-safe RFID tag preferably includes a split-ring (or shield) conductor formed on one side of a dielectric, a coil antenna conductor formed on the opposite side of the dielectric, and an RFID chip. The split ring conductor is separated from the coil antenna conductor by a dielectric. Further, the split-ring conductor covers a majority of the coil antenna conductor such that the split-ring conductor capacitively couples to the coil antenna conductor via the dielectric. In addition, the split ring conductor includes a gap that allows microwave current to flow through the coil antenna conductor, but no portion of the coil antenna conductor in the gap interacts with the microwave current, which prevents arcing.

In another embodiment, a microwave-safe RFID tag device includes a second open loop conductor that is rotated relative to the first open loop conductor such that the gaps of the conductors are not aligned and current does not flow in the gaps. The coil antenna conductor is then placed between and capacitively coupled to the first and second split ring conductors, effectively shorting the coil antenna conductor to the first and second split ring conductors to prevent arcing and excessive current flow along the coil antenna conductor.

In another embodiment of the invention, a microwave-safe RFID tag includes an RFID chip and a shielding strap on a coil antenna conductor, wherein a split ring conductor is formed on top of the RFID chip and the shielding strap. Specifically, RFID chips are affixed to the center and outer edges of the coil antenna conductor to create a resonant circuit.

Although the discussion contained herein is primarily directed to food products placed in a microwave oven for the purpose of cooking, thawing, heating, or reheating the food product, it should be understood that the present invention is not limited to use with food products. More specifically, the present invention may be used in any other setting or process where it is desirable to attach an RFID tag to an item to be placed in or near a microwave oven or field, such as during manufacturing.

To the accomplishment of the foregoing and related ends, certain illustrative aspects of the disclosed innovation are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles disclosed herein can be employed and is intended to include all such aspects and their equivalents. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings.

Drawings

Fig. 1 shows a top perspective view of a basic HF RFID tag according to the disclosed architecture.

Fig. 2 illustrates a top perspective view of a microwave-safe RFID tag in accordance with the disclosed architecture.

Fig. 3 illustrates a perspective view of a microwave-safe RFID tag having an HF coil antenna according to the disclosed architecture.

Fig. 4 illustrates a front perspective view of a gap between shielding conductors of a microwave-safe RFID tag in accordance with the disclosed architecture.

Fig. 5 illustrates a top perspective view of a microwave-safe RFID tag having a shield formed on opposite sides of a substrate and having connections to bridging conductors in accordance with the disclosed architecture.

Fig. 6A illustrates a top perspective view of a bottom shield conductor of a microwave-safe RFID tag in accordance with the disclosed architecture.

Fig. 6B illustrates a top perspective view of an HF RFID inlay of a microwave-safe RFID tag according to the disclosed architecture.

Fig. 6C illustrates a top perspective view of a top shield conductor of a microwave-safe RFID tag in accordance with the disclosed architecture.

Fig. 7 illustrates a top perspective view of a microwave-safe RFID tag in which a small laser-cut gap is created between coil conductors in accordance with the disclosed architecture.

Fig. 8A illustrates a top perspective view of a shielding tape according to the disclosed architecture.

Fig. 8B illustrates a top perspective view of a shield conductor to be placed on a tape according to the disclosed architecture.

Fig. 8C illustrates a top perspective view of a coil conductor of a microwave-safe RFID tag in accordance with the disclosed architecture.

Fig. 9 shows another starburst (starburst) shielding structure of the present invention.

Detailed Description

The present invention is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding thereof. It may be evident, however, that the innovation can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing them.

An RFID tag that can withstand high field emissions and can be considered microwave safe so that the tag does not need to be removed from a product such as food before cooking, thawing, heating and/or reheating in a device (e.g., a microwave oven) and can provide data to control the cooking process. In one embodiment, the RFID tag includes a split ring (or shield) conductor formed on one side of a substrate (or dielectric), a coil antenna conductor formed on the opposite side of the substrate, and an RFID chip. The split-ring conductor is capacitively coupled to the coil antenna conductor through a dielectric, and a gap in the split-ring conductor prevents arcing. Further, the RFID chip may carry data related to the product or food to which the RFID is attached and/or the process that needs to be performed by the microwave oven. The RFID reader system reads data on the RFID chip to authorize and/or control microwave processes, such as cooking, heating, reheating, or thawing food products.

Referring first to the drawings, FIG. 1 shows a standard High Frequency (HF) RFID tag device 100. In one embodiment, HF RFID tag device 100 is a planar structure of a conductive antenna assembly 102 in a spiral configuration or any other suitable configuration as is known in the art. Further, the planar structure is shown as rectangular, but may be any suitable shape known in the art, such as circular, square, triangular, or the like. The planar structure having a spiral-type configuration forms a plurality of gaps 104 between the conductive antenna assemblies 102. Additionally, the gap 106 in the conductive antenna assembly 102 itself is where the RFID chip 108 is located, such that the RFID chip 108 is placed in the coil of the conductive antenna assembly 102. In addition, the center 112 of the RFID tag device 100 and the outer edge 114 of the planar structure of the conductive antenna assembly 102 are bridged together with the conductive trace 116 to form the inductor (or bridge conductor) 110 on the HF RFID tag device 100 and resonate at the desired frequency.

Typically, HF RFID tags operate in the frequency band of 100kHz to 15MHz, with a specific standard frequency of 13.56 MHz. Furthermore, typical read ranges can be up to about 1 m; however, for applications on many mobile devices, such as cellular phones operating according to the Near Field Communication (NFC) standard, the range can only be 10-15mm, depending on the size of the RFID tag. The distance between the tag and the reader is in the near field and the coupling is mainly magnetic and usually uses a coil-type antenna designed as an inductor that capacitively resonates with the RFID chip.

As shown in fig. 2, an RFID tag 200 is shown that has high transmission field resistance and is generally considered microwave safe, and is designed to be placed inside a heating device without damaging the food or other product to which the RFID tag 200 is attached. The RFID tag 200 may be secured to the food item by any suitable means known in the art, such as by a GRAS (generally recognized as safe) adhesive. Further, as shown in FIG. 1, the RFID tag 200 may be a dual mode tag or a single mode tag, and may include an HF core component in communication with an HF reader system. In general, the RFID tag 200 may be any suitable size, shape, and configuration known in the art without affecting the overall concept of the invention. Those of ordinary skill in the art will appreciate that the shape and size of the RFID tag 200 as shown in fig. 2 is for illustrative purposes only and that many other shapes and sizes of the RFID tag 200 are within the scope of the present disclosure. While the dimensions (i.e., length, width, and height) of the RFID tag 200 are important design parameters for good performance, the RFID tag 200 may be any shape or size that ensures optimal performance during use.

In one embodiment, RFID tag device 200, which is capable of withstanding microwave ovens, includes a planar structure of conductive antenna assembly 202 in a spiral configuration or any other suitable configuration known in the art. The present invention contemplates the electrically conductive antenna assembly 202 being metallic, but may be fabricated from any suitable material known in the art. Further, the planar structure is shown as rectangular, but may be any suitable shape known in the art, such as circular, square, triangular, or the like. The planar structure having a spiral-type configuration forms gaps 204 between the conductive antenna assemblies 202. Additionally, at least one gap 206 in the conductive antenna assembly 202 itself is where to place the RFID chip 208 in order to place the RFID chip 208 in the coil of the conductive antenna assembly 202.

In addition, the center 218 of the microwave-safe RFID tag device 200 and the outer edge 220 of the planar structure of the conductive antenna assembly 202 may be bridged with conductive traces 222 to form an inductor (or bridging conductor) 210 that resonates at a desired frequency throughout the microwave-safe RFID tag device 200. In addition, the microwave-safe RFID tag device 200 includes a second conductor 212 in the form of an open loop or any other suitable shape known in the art. The second conductor (or loop conductor) 212 is separated from the bridge conductor (or coil conductor) 210 by a dielectric 214. The dielectric 214 is typically a plastic or adhesive, or any other suitable dielectric material known in the art.

Preferably, the annular conductor 212 covers most of the conductive antenna assembly or coil 202 as shown in FIG. 2, leaving a small gap 216 or open space that does not cover the coil 202. The split ring conductor 212 is shaped and sized as part of the overall microwave-safe RFID tag device 200 structure to provide controlled interaction with the microwave field to minimize heating and prevent arcing. In general, the design of the split ring conductor 212 is varied, and any suitable shaped conductor known in the art may be used. Furthermore, common features of the split ring conductors 212 are rounded corners (rounded corners), defined side lengths compared to the wavelength at microwave frequencies, and controlled gaps between the ring elements (i.e., coils 202).

Split ring conductor 212 is capacitively coupled to coil 202 through dielectric 214. For example, for a 10mm square area and a dielectric with a thickness of 325 μm k, the capacitance is106pF (picofarad). At 13.56MHz, the equivalent coupling impedance to the coil 202 is 110 ohms, which will have minimal effect on coil operation. At 2.45GHz, the coupling impedance is about 0.61 ohms, effectively shorting the coil and the loop. This prevents arcing between the coil elements and excessive current flow throughout the length of the coil conductor 202. Thus, the prevention of arcing reduces the energy applied to the microwave-safe RFID tag 200, and then also minimizes heating of the microwave-safe RFID tag 200. Thus, the microwave-safe RFID tag 200 may be read before or during high power microwave transmission (i.e., 2.45 GHz).

The loop conductor 212 has openings (or gaps) 216 to prevent it from acting as a short turn in which current will flow when placed in a magnetic field in the case of magnetic interaction of the loop conductor 212 with the coil antenna 202. In the region of the opening (or gap) 216, because either side of the coil conductor 202 is securely coupled to the loop conductor 212, microwave current flows through the coil conductor 202 over the length defined by the gap 216 in the loop conductor 212. The dimensions of the gap 216 are selected such that any structure of the coil 202 in the gap 216 will not interact with the microwave field; thus, for the purposes of the present invention, the wavelength should be less than one tenth, or about 12mm, of the wavelength of the microwave frequency.

In addition, the RFID chip 208 of the microwave-safe RFID tag 200 carries data related to the process that the microwave oven needs to perform. Specifically, the data received from the RFID chip 208 may include, but is not limited to, a unique identifier of the RFID tag 200, a product identification, product "use before date" data, product "consumption before date" date, allergen information, cooking parameters for the food, such as heating, stirring, and a description of residence time after heating.

For example, with respect to an expired product "use before this day" date or "consume before this day" date, the RFID chip 208 may be used to prevent microwaves from thawing, cooking, heating, or reheating food without manual manipulation, thereby preventing a user from unknowingly eating food no longer suitable for consumption and preventing illness. This function is particularly useful, for example, when the printing on the message containing the product "used before the day" or "consumed before the day" is no longer recognizable by the human eye or separate from the food product.

In addition, the authorization required to cover the RFID chip 208 may be different for different food products and/or different users. For example, overrides required for baby food, seafood, or food with particular known allergens (e.g., peanut-containing food) may be considered high risk, and may require a particular code rather than simple yes/no or verbal confirmation. Furthermore, the specific product data may also be combined with data about the user (e.g. allergen information) to prevent cooking actions, issue alerts, request verbal confirmation, etc. In addition, the RFID chip 208 may also be associated with a sensor that can detect whether the food has thawed, chilled, or frozen, and the sensor's information or output can in turn be used to appropriately modify cooking parameters without further user intervention. For example, for frozen food products, the sensor output may be used to instruct a microwave oven to first thaw the food product at one microwave power setting and then cook the food product at a different power setting. Alternatively, if it is determined by the sensor that the food product has thawed, the sensor output may be used to instruct the microwave oven to bypass the thawing process and to directly perform the cooking process, thereby saving the time required for operation and the energy required to operate the microwave oven during the thawing process.

In another embodiment as shown in fig. 3, a microwave-safe RFID tag device 300 is shown, in which a shield conductor 302 is proximate to an HF RFID coil antenna (or coil conductor) 304. In addition, the shield conductor 302 is separated from the coil conductor 304 by a dielectric (or substrate) 306, such as plastic or adhesive, or any other suitable material known in the art. Additionally, the microwave-safe RFID tag device 300 may be made in a variety of ways. For example, the shield conductor 302 and the coil conductor 304 may be located on opposite surfaces of a substrate (or dielectric) 306, such as a PET substrate 306, with the coil conductor 304 etched on one side of the PET substrate 306 and the shield conductor 302 etched on the other side.

Alternatively, the shield conductor 302 and the coil conductor 304 may be located on opposite surfaces of the PET substrate 306, with the coil conductor 304 being laser cut on one side of the PET substrate 306 and the shield conductor 302 being laser cut on the other side of the PET substrate 306. Alternatively, the shield conductor 302 and the coil conductor 304 may be located on opposite surfaces of the PET substrate 306, with the coil conductor 304 laser cut on one side of the PET substrate 306 and the shield conductor 302 die cut on the other side of the PET substrate 306. Alternatively, the shield conductor 302 and the coil conductor 304 may be located on opposite surfaces of the PET substrate 306, in which the coil conductor 304 is laser cut or etched on one surface of the PET substrate 306, the shield conductor 302 is pre-cut, and the shield conductor 302 is applied with an adhesive on the other surface of the PET substrate 306.

Alternatively, the shield conductor 302 and the coil conductor 304 may be on the same surface of the PET substrate 306, with the coil conductor 304 being laser cut or etched on one surface of the PET substrate 306, and the shield conductor 302 being cut in advance and applied to the same surface of the PET substrate 306 with an adhesive as an additive component. Or finally, the shield conductor 302 and the coil conductor 304 may be located on the same surface or on opposite surfaces of the PET substrate 306, with the shield conductor 302 applied as a printed structure on the back side of the PET substrate 306 or on top of the coil conductor 304 with a suitable dielectric separator therebetween, such as varnish, or any other suitable dielectric material known in the art.

Fig. 4 provides a view of a microwave-safe RFID tag 400, particularly the area where the gap 402 in the split-ring (or shield) conductor 404 is above the HF coil antenna conductor 406. The gap 402 has a large overlap area 408 on either side. The large overlap area 408 provides low impedance coupling to the coil antenna conductor 406 on either side of the coil turns because they are capacitively shorted together by the shield conductor 404. Thus, the shield conductor 404 acts as a single wide conductor capable of carrying current through the gap 402. This prevents arcing between coil elements (or turns) and excessive current flow through the entire length of the coil antenna conductor 406. In the region of the gap 402, microwave current flows through the coil element over the length defined by the gap 402, as it is rigidly coupled to the split-ring conductor 404 on either side of the coil antenna conductor 406. The size of the gap 402 is chosen such that no structure of the coil elements in the gap 402 will interact with the microwave field, e.g. the size of the gap 402 should be less than one tenth of the wavelength at microwave frequencies, or about 12 mm.

Fig. 5 shows another embodiment of a microwave-safe RFID tag device 500 that includes a split-ring (or shield) conductor 502 formed on one side of a substrate (or dielectric) 514, a coil antenna conductor 504 formed on the opposite side of the substrate 514, and an RFID chip 506. In the microwave-safe RFID tag device 500, the split-ring shielded conductor 502 also acts as an HF bridge 516 between the center 508 and the edge 510 of the coil antenna conductor 504, causing the continuous conductor to resonate with the RFID chip 506 at 13.56 MHz. The bridging function is achieved by providing a low resistance (i.e., 10 ohm) path using a crimp connection 512 or other connection means (e.g., plated through holes, etc.) between the top and bottom conductors (i.e., the shield conductor 502 and the coil antenna conductor 504) or any other suitable connection means known in the art. If the shield conductor 502 is applied directly as an additional conductor on the coil antenna conductor 504 without the substrate 514 in between, the connection may be made by a suitable conductive adhesive as is known in the art.

Fig. 6A-C illustrate another embodiment of a microwave-safe RFID tag device 600 that includes two split ring shields (shield 1602 and shield 2604), an HF RFID coil antenna conductor (or HF RFID inlay) 610, and an RFID chip 616. The microwave-safe RFID tag device 600 includes a first split-ring (or shield) conductor (shield 1)602 formed with a gap 606 at a bottom edge 608 of the shield 1 conductor 602, and wherein the shield 1 conductor 602 is located to one side of a coil antenna conductor 610. The microwave-safe RFID tag device 600 also includes a second split-ring (or shielded) conductor (shield 2)604 having a gap 612 formed in a top edge 614 of the shield 2 conductor 604, wherein the shield 2 conductor 604 is on the opposite side of the coil antenna conductor 610.

By rotating the two shield conductors (i.e., shield 1602 and shield 2604) relative to each other, the gaps 606 and 612 of the shield conductors (602 and 604) are located at different positions. Therefore, although neither of the two shield conductors (602 and 604) is short-circuited to the coil antenna conductor 610, since the gaps (606 and 612) in the shield 1 and the shield 2(602 and 604) are located at different positions, no current flows into the coil antenna conductor 610 at any point when the coil antenna conductors 610 bridge each other at 2.45 GHz. Thus, the microwave-safe RFID tag device 600 having two shield conductors (602 and 604) minimizes the current in the coil antenna conductor 610.

Fig. 7 shows another embodiment of a microwave-safe RFID tag device 700 that includes a split-ring (or shield) conductor 702 formed on one side of a substrate (or dielectric) 704, a coil antenna conductor 706 formed on the opposite side of the substrate 704, and an RFID chip 718. In the microwave-safe RFID tag device 700, the coil antenna conductor 706 also acts as an HF bridge 708 between the center 710 and the edge 712 of the coil antenna conductor 706 to resonate the continuous conductor with the RFID chip 706 at 13.56 MHz. The bridging function is achieved by providing a low resistance (i.e., 10 ohm) path using a crimp connection 714 or other connection means (e.g., plated through holes, etc.) or any other suitable connection means known in the art.

In addition, the coil antenna conductor 706 includes a small gap 716 in the range of 10 μm to 100 μm or any other suitable size known in the art. The small gap 716 serves to isolate the coil turns of the coil antenna conductor 706. Because the gap 716 is small, the coupling capacitance between the coil turns is low impedance at 2.45GHz, making the coil of the coil antenna conductor 706 look like a solid ring at 2.45GHz, with no gap to prevent arcing.

Fig. 8A-C disclose an embodiment of a microwave-safe RFID tag device 800, the microwave-safe RFID tag device 800 including an RFID chip 806 connected to a strap 808, wherein the RFID chip 806 and the strap 808 are located on a coil antenna conductor 820, and a split ring (or shielding) conductor 802 is formed on top of the RFID chip 806 and the strap 808. Specifically, the RFID chip 806 is connected to two wires 810 and two pads 812 designed to connect (or bridge) it to the center 814 and outer edge 816 of the coil antenna conductor 820, creating a resonant circuit. The bridging (or connecting) function is accomplished by connecting the two wires 810 and the two pads 812 of the RFID chip 806 using a crimp connection 818 or other connection means (e.g., plated through holes, etc.) or any other suitable connection means known in the art.

In addition, the tape 808 incorporates a top shield metal layer that forms the shield tape 808. The shielding tape 808 serves as a continuous conductor over the coil antenna conductor 820. In addition, the shield conductor 802 includes open loops (or gaps) 804, as described above, and is placed on top of the coil antenna conductor 820, shorting the gaps 804 in the loop (or shield) conductor 802 at 2.45GHz by the shield strips 808 and capacitive coupling. Thus, the microwave-safe RFID tag device 800 prevents any current from flowing through the coil antenna conductor 820, and thus arcing, at the location where the gap 804 exists in the split-ring shielded conductor 802.

Importantly, the data contained on the RFID chip 806 (e.g., "use before this day" or "consume before this day" data) can be combined with other data about the manufacturer or a particular user to activate different cooking parameters, override the authorization level required for cooking parameters, etc. The data relating to the user may include, but is not limited to, information relating to allergic reactions, cooking time, age of the user, etc. This data, as well as manufacturer data and/or product data, is used to control whether a particular microwave operation (e.g., thawing, heating, reheating, cooking, etc.) is authorized, and if not directly authorized, further action is required by the user. The further action by the user may include entering a password using an RFID card, using a Near Field Communication (NFC) enabled phone, etc., or any other suitable action known in the art to take an action.

More specifically, the process may begin with reading or interrogating the RFID tag 800 and collecting and analyzing data related to the product bearing the RFID tag. The RFID tag 800 may be read or interrogated inside or outside of the microwave cavity depending on the particular RFID reader system used. Based on the collected data, it may then be determined whether the data read from the RFID tag 800 indicates that the tagged product has expired (i.e., beyond its "best before this day" or "consumption before this day" date). If the product is not an expired product, the microwave process may proceed and the microwave control panel may control the appropriate microwave functions (e.g., thawing, heating, reheating, or cooking) for the RFID tagged product. On the other hand, if the product is out of date, it may be further determined whether the product is a critical product. Whether a product is a "key product" may be defined by any number of user-specified parameters. For example, "critical products" may include baby products, products that are susceptible to food poisoning if out of date, and the like. If the product is not a critical product, the microwave process may directly perform the desired microwave function (i.e., defrost, heat, reheat, cook, etc.) and then control the desired microwave function via the microwave control panel.

For example, if a product with an RFID tag is beyond its "best-before-eat date" (i.e., out-of-date), but not a critical product (e.g., based on a low likelihood of food poisoning), such as a vegetable, the microwave oven may be directed to perform the desired microwave function. This may occur regardless of other parameters (e.g., cooking instructions) with or without the RFID tag. On the other hand, if the product is both out-of-date and critical, a manual override or some form of verification may be required to continue. For example, if the product belongs to a key product category such as shellfish or baby food, the microwave oven will require further authorization to override the lock, such as a password. The same procedure can also be used for food products containing allergens. If the user has previously defined that a person allergic to peanuts may be using the microwave oven, any peanut-containing product displayed to the microwave oven will require a high level override (e.g., a password) and may sound an alarm.

Another aspect may relate to the age of the user. For example, if the product appears to become very hot during cooking, such as those containing high levels of syrup, overrides are required if the child is at home to prevent the child from eating too hot food and suffering from burning or scalding. Upon further authorization, the process will proceed directly to the desired microwave function (e.g., cook, thaw, heat, reheat, etc.), and the microwave oven control panel controls the microwave process for the RFID tagged product. As previously mentioned, different levels of authorization may be established depending on the critical nature of the problem and/or the specific needs of the user.

As previously discussed, the RFID tag 800 may further include some form of sensor. For example, the sensor may be a temperature sensor that may indicate whether the RFID tagged product has thawed, chilled or frozen, or any other sensor known in the art, such as a humidity sensor, etc. Based on the sensor status and the RFID data, the microwave oven may then select the appropriate cooking method as determined by the microwave oven controller (i.e., based on whether the food has thawed, chilled, or frozen), which then uses the data read from the RFID tagged product to select the appropriate microwave function to perform.

For example, for frozen food products, the output of the sensor may be used to instruct the microwave oven controller to first thaw the food product at one microwave power setting and then cook the food product at a different power setting. Alternatively, if it is determined by the sensor that the food product has thawed, the sensor output may be used to instruct the microwave oven controller to bypass the thawing process, directly performing the cooking process, thereby saving time and energy required to operate the microwave oven during the thawing process, which is not necessary in this particular application.

In addition, tag data obtained from the RFID tag 800 may trigger a lookup from an online web service or external database for the correct cooking parameters for that particular food product. In particular, the microwave oven controller may send user interface data to an online system/web service or external database to obtain additional information about the food product and how to prepare the food product. For example, the web service may provide other information about the food product, such as reminders about how to best cook the food product in the microwave oven, appropriate power settings to use, or whether the food product has been better thawed, refrigerated, or frozen. The cooking parameters may then be combined with the user's preferences for certain food products, e.g. preferences such as how the state of the meat should be prepared or the desired softness of vegetables, bread, etc. The microwave oven controller may then utilize the cooking parameters from the web service or other external database and the user preferences to control the microwave cooking process of the food product.

Fig. 9 shows another embodiment of the present invention. Figure 9 shows an alternative form of shielding of the aforementioned split ring; as shown, the alternative is a starburst 905, with a series of lines radiating from a central point inside the coil to space outside the coil. The line widths are made such that they couple sufficiently with the lines of the coil, e.g., capacitively, such that they short circuit at 2.45GHz, terminating the gap in the small arc in the space between the gaps 901, but providing relatively low coupling between the HF antenna coils to maintain performance. If the gap is kept at a small fraction of wavelength 907, e.g., λ/20 or less, the interaction between the gap and the 2.45GHz energy will be minimized. It should be understood that the number of arms on a starburst may vary depending on the desired level of gap termination.

What has been described above includes examples of the claimed subject matter. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the claimed subject matter are possible. Accordingly, the claimed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim.