RFID antenna for suppression of useless RF signals

Abstract

An RFID tag is shown and described herein. The RFID tag includes an RFID antenna configured to provide attenuation of useless signals at relatively high frequencies (e.g., above 2 GHz and in the range of about 2 GHz to about 5 GHz). The RFID tag includes a dipole antenna having tuning elements that attenuate or suppress signals at high frequencies, such as those at which, for example, a microwave oven operates.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Patent Application No. 63 / 348,616, filed on June 3, 2022, entitled “RFID ANTENNAFOR REJECTING UNWANTED RF SIGNALS,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to an RFID antenna suitable for use in applications where the tag will be exposed to a power output exceeding the maximum input power of a conventional RFID tag. The RFID antenna is configured to suppress out-of-band signals. The present invention also relates to tags and packaging including such an RFID antenna and uses thereof. Background Art

[0004] RFID tags are used to tag a wide variety of consumer goods to provide a way to track items. The food industry and food products are industries that are using RFID tags more and more and the demand will continue to grow. RFID technology can be used to tag and track products with expiration dates, such as but not limited to meat, dairy products, fruits, vegetables and other such products. RFID technology can be employed in systems to identify items that are approaching their expiration dates. Stores can take this information and, if necessary, reduce the price of the item to entice customers to purchase the product before its expiration date. Products that are past their expiration date can be quickly located and removed from the sales area.

[0005] In the case of some food products, such as frozen products or certain refrigerated products, the product may be provided so that it should be heated in a microwave oven before consumption. In many instances, the RFID technology is embedded or applied to the packaging in a manner that is not or may not be removed before being exposed to microwave operating conditions. Summary of the invention

[0006] The following presents the invention summary of the present disclosure to provide a basic understanding of some aspects. The present invention summary is intended to neither indicate key elements or important elements nor to limit any limitation to the embodiments or claims. In addition, the present invention summary can provide a brief summary of some aspects described in more detail in other parts of the present disclosure.

[0007] In one aspect, an RFID tag is provided that includes an RFID antenna that attenuates input power signals at frequencies above 2.4 GHz. In one embodiment, the RFID tag includes an RFID antenna configured as a dipole antenna that includes a loop segment and an antenna segment extending from the loop segment, wherein the antenna segment includes a tuning element coupled to the antenna segment. The tuning element provides attenuation of input signals at frequencies above 2.4 GHz.

[0008] In another aspect of the present invention, there is provided a dipole antenna for a radio frequency identification tag, the dipole antenna having a loop region; a first dipole element electrically connected to the loop region and terminating at a first pad; and a second dipole element electrically connected to the loop region and terminating at a second pad. The first dipole element and the second dipole element extend in directions opposite to each other along a horizontal axis of the dipole antenna. At least one tuning element, wherein the at least one tuning element extends from one or both of the first dipole element and the second dipole element, the shape, size and position of each of the at least one tuning element being selected to obtain a desired attenuation level of signals within a predetermined frequency band, wherein the dipole antenna is tuned using the at least one tuning element to operate within a predetermined operating frequency range.

[0009] In some embodiments, the desired attenuation level of the signal is at least 27 dB. In other embodiments, the desired attenuation level of the signal is at least 35 dB. In further embodiments, the predetermined frequency band is greater than 2 GHz, between 2.4 GHz and 4.0 GHz, or between 2 GHz and 14.5 GHz. In further embodiments, at least one tuning element provides a desired attenuation level of 0 dB to about 40 dB, about 5 dB to about 35 dB, about 10 dB to about 30 db, or about 15 dB to about 25 dB for a predetermined frequency band between about 2.4 GHz and about 4.0 GHz. In other embodiments, at least one tuning element provides a desired attenuation of about 35 dB to about 40 dB for a predetermined frequency band between about 2.4 GHz and about 4.0 GHz.

[0010] In further embodiments, the shape of at least one tuning element can be triangular, rectangular, circular, elliptical, trapezoidal, pentagonal, hexagonal, "L"-shaped, trace or block; wherein at least one tuning element can all have the same shape, different shapes or a combination of various shapes.

[0011] In further embodiments, the first dipole element and the second dipole element each have at least one tuning element of the same size at an equivalent position along the dipole element, wherein the at least one tuning element each extends from the equivalent position and has an "L" shape with a short leg and a long leg; the short leg of the "L" shape is electrically connected to the first dipole element and the second dipole element.

[0012] In some embodiments, the first dipole element and the second dipole element each have a meander pattern, wherein a physical length of the first dipole element is shorter than an electrical length of the first dipole element, and a physical length of the second dipole element is shorter than an electrical length of the second dipole element.

[0013] In a further embodiment, the dipole antenna further includes a circuit chip electrically connected to the loop area using a first connection portion of the loop area and a second connection portion of the loop area, the first connection portion and the second connection portion of the loop area are located on a first side of the loop area, and the first dipole element and the second dipole element are electrically connected to the second side of the loop area, wherein the first side and the second side of the loop area are located on opposite sides of the loop area.

[0014] In other embodiments, the first and second connections of the loop region are located on a first side of the loop region, and the first and second dipole elements are electrically connected to the first side of the loop region, wherein the first and second sides of the loop region are located on opposite sides of the loop region.

[0015] In further embodiments, the first and second connections of the loop region are located on a first side of the loop region, and the first and second dipole elements are electrically connected at a position between the first and second sides of the loop region, wherein the first and second sides of the loop region are located on opposite sides of the loop region.

[0016] In yet another aspect of the present invention, a radio frequency identification (RFID) tag is provided, the RFID tag having a dipole antenna formed on a substrate having an adhesive for attaching the tag to a surface. The dipole antenna has a loop region; a first dipole element electrically connected to the loop region and terminating at a first pad; and a second dipole element electrically connected to the loop region and terminating at a second pad. The first dipole element and the second dipole element extend in directions opposite to each other along a horizontal axis of the dipole antenna.

[0017] Some embodiments include at least one tuning element, wherein the at least one tuning element extends from one or both of the first dipole element and the second dipole element, the shape, size, and position of each of the at least one tuning element being selected to obtain a desired attenuation level of signals within a predetermined frequency band. The dipole antenna is tuned using the at least one tuning element to operate within a predetermined operating frequency range.

[0018] In yet another aspect of the present invention, an article is provided. The article includes a radio frequency identification (RFID) tag attached to the article. The RFID tag includes a dipole antenna formed on a substrate having an adhesive for attaching the tag to a surface. The dipole antenna has a loop region, a first dipole element electrically connected to the loop region and terminated at a first pad, and a second dipole element electrically connected to the loop region and terminated at a second pad. The first dipole element and the second dipole element extend in directions relative to each other along the horizontal axis of the dipole antenna. At least one tuning element is provided, wherein the at least one tuning element extends from one or both of the first dipole element and the second dipole element, and the shape, size and position of each of the at least one tuning element are selected to obtain a desired attenuation level of a signal within a predetermined frequency band, wherein the dipole antenna is tuned using at least one tuning element to operate within a predetermined frequency range. When the RFID tag is exposed to RF energy exceeding a predetermined power level within a predetermined frequency band, the desired attenuation level is selected to prevent the RFID tag from thermally damaging the article.

[0019] In some embodiments, the predetermined power level is greater than +20 dBm and the predetermined frequency band is greater than 2 GHz. In other embodiments, the predetermined power level and the predetermined frequency band are those generated by a microwave oven.

[0020] The following description and the accompanying drawings disclose various illustrative aspects. Some improvements and novel aspects can be clearly identified, while other aspects may be obvious from the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings illustrate various systems, devices, apparatus, and related methods, wherein like reference characters refer to like parts throughout, and in the drawings:

[0022] Figure 1A is a representation of an RFID tag according to an embodiment of the present invention;

[0023] Figure 1B It is a representation of the contrast RFID tag;

[0024] Figure 1C is a representation of a cross-section of an RFID tag according to an embodiment of the present invention;

[0025] Figure 2 is used for Figure 1B The conjugate matching factor of the comparison antenna is displayed; and

[0026] Figure 3 is used for Figure 1A The conjugate matching factor of the RFID tag is shown. DETAILED DESCRIPTION

[0027] Reference will now be made to exemplary embodiments, examples of which are illustrated in the accompanying drawings. It should be understood that other embodiments may be utilized and that structural and functional changes may be made. In addition, the features of the embodiments may be combined or substituted. Therefore, the following description is presented only by way of example and should not in any way limit the various substitutions and modifications that may be made to the illustrated embodiments. In the present disclosure, many specific details provide a thorough understanding of the subject disclosure. It should be understood that various aspects of the present disclosure may be practiced in the context of other embodiments that do not necessarily include all aspects described herein.

[0028] As used herein, the words "example" and "exemplary" mean an instance or illustration. The words "example" or "exemplary" do not indicate key or preferred aspects or embodiments. Unless the context suggests otherwise, the word "or" is intended to be inclusive rather than exclusive. As an example, the phrase "A employs B or C" includes any inclusive arrangement (e.g., A employs B; A employs C; or A employs both B and C). On the other hand, the articles "a" and "an" are generally intended to mean "one or more" unless the context suggests otherwise.

[0029] Provided is an RFID tag suitable for use in an environment such as a microwave oven. An RFID tag or label may be exposed to microwave radiation during its use. For example, an RFID tag may be used on food packaging (frozen or non-frozen) for use in an inventory or product tracking system. Many such products may be microwaveable products, in which the RFID tag is not removed before exposure to microwave radiation. RFID tags may also be used in medical or laboratory environments to identify medical specimens, manufactured products, forensic samples, or other laboratory samples that are processed with the aid of microwave energy in a laboratory or production equipment. In a commercial or experimental laboratory or production equipment, microwave energy is supplied as electromagnetic radiation at a frequency of about 2.45 GHz or other frequencies in the range of about 2 GHz to 14.5 GHz. Commercial or household microwave ovens provide microwave energy as 2.45 GHz frequency electromagnetic radiation to heat food and beverages. In either case, the RFID tag or label may be exposed to radiation at a frequency of about 2.45 GHz at a power level ranging from 100 watts to 1200 watts, for a time range of from 1 second to many hours, with continuous or pulsed microwave exposure.

[0030] Exposing an RFID tag or label to electromagnetic radiation generated by a microwave source (such as a microwave oven) may cause the RFID tag or label to fail. If such RFID tags are exposed to high microwave power levels, such as microwave powers in the range of 100 watts to 1200 watts discussed above, they will typically become ineffective. For example, a microwave oven typically outputs 1000 watts of power (+60dBm). This is 40dB higher than the maximum input power of most UHF RFID devices (about +20dBm). In this case, the electromagnetic energy in the microwave oven may cause the RFID tag or antenna element to become very hot, possibly hot enough to burn, thereby creating a safety hazard, which may be a worse problem than the problem of tag failure. The RFID tag may also arc to the microwave oven power supply or other electrical ground in the microwave oven, which produces sparks and may damage the power supply. In these cases, the object with the RFID tag may also be damaged.

[0031] Steering Figures 1A to 1C , the RFID tag 100 includes an RFID antenna 102 disposed on a substrate 101. The RFID antenna 102 is disposed on the substrate material in the form of a transmission line. The transmission line is provided as a conductive trace in a pattern typically formed by a conductive metal. The pattern is configured to transform the RFID integrated circuit to match the pattern of free space (377 ohms). This is accomplished by selecting the width and length of the antenna element. The RFID antenna is designed to operate between 860 MHz and 960 MHz. Conventional antennas can provide some suppression of RF signals at 2.45 GHz, but the attenuation provided (if any) may not be sufficient to prevent the tag from burning.

[0032] According to the present technology, an RFID antenna is provided with tuning elements on the antenna segments. In one embodiment, the antenna is a dipole antenna having an open loop from which the antenna segments extend. The tuning elements are associated with the antenna segments. The tuning elements are provided as open circuit elements that are added to the two antenna segments of the dipole antenna. It has been found that this provides another tuning element suitable for blocking or attenuating incoming signals at frequencies greater than 2.45 GHz. The open circuit elements are provided in a shape and / or pattern to provide a desired level of attenuation of unwanted signals.

[0033] Figures 1A to 1C An embodiment of an RFID antenna 102 according to the present technology is shown. RFID tag 100 includes a folded dipole antenna 102. Folded dipole antenna 102 includes a loop region 103 having a first connection 104 and a second connection 106, each of which is connected to a circuit chip 108. The folded dipole antenna includes dipole elements (antenna sections) 110 and 120, which extend from the loop region in directions opposite to each other along the horizontal axis of dipole antenna 102. Figures 1A to 1C The first dipole element 110 and the second dipole element 120 in the embodiment are configured as meander dipole elements. The dipole elements 110 and 120 extend away from the loop region 103 along the horizontal axis 145 of the antenna 102 like arms, and are configured as a wavy pattern with wavy elements. The overall pattern of the antenna 102 forms a single dipole. In some embodiments, the dipole elements 110 and 120 may also have pads 130 and 140 at opposite ends of the loop region 103. When the pads 130 and 140 are present, the first dipole element 110 extends from the loop region 103 through the first pad 130, and the second dipole element 120 extends from the loop region 103 through the second pad 140.

[0034] In one embodiment, dipole elements 110 and 120 have the same length and pattern design. Figures 1A to 1C As shown, the pattern for antenna segments 110 and 120 is provided as a square wave. The number of cycles, the period of the wave, the width of the wave segment, etc. can be selected to tune the antenna to operate within a predetermined operating frequency range. In an embodiment, the predetermined operating frequency range can be between 860 MHz and 960 MHz. In another embodiment, dipole elements 110 and 120 can have the same length, but have different patterns. In yet another embodiment, the dipole elements can differ from each other in length and / or the pattern of the dipole elements.

[0035] In an embodiment, first dipole element 110 may extend from loop region 103 and terminate at first pad 130. Additionally, second dipole element 120 may extend from loop region 103 and terminate at second pad 140.

[0036] In an embodiment, a physical length of first dipole element 110 measured from loop region 103 through first pad 130 of first dipole element 110 is shorter than an electrical length of first dipole element 110 , and a physical length of second dipole element 120 measured from loop region 103 through second pad 140 of second dipole element 120 is shorter than an electrical length of second dipole element 120 .

[0037] In an embodiment, circuit chip 108 may be electrically connected to loop region 103 using first connection portion 104 of loop region 103 and second connection portion 106 of loop region 103 , wherein first connection portion 104 and second connection portion 106 of loop region 103 are located at first side 112 of loop region 103 , and first dipole element 110 and second dipole element 120 are electrically connected to second side 114 of loop region 103 , wherein first side 112 and second side 114 of loop region 103 are located at opposite sides of loop region 103 .

[0038] In another embodiment, circuit chip 108 may be electrically connected to loop region 103 using first connection portion 104 and second connection portion 106 of loop region 103 located at first side 112 of loop region 103 , and first dipole element 110 and second dipole element 120 are electrically connected to first side 112 of loop region 103 .

[0039] In yet another embodiment, the circuit chip 108 may be electrically connected to the loop region 102 using the first connection portion 104 and the second connection portion 106 of the loop region 103 located at the first side 112 of the loop region 103 , and the first dipole element 110 and the second dipole element 120 are electrically connected at a position between the first side 112 and the second side 114 of the loop region 103 .

[0040] Therefore, it is contemplated that circuit chip 108 and first dipole element 110 and second dipole element 120 may be placed anywhere in loop region 103 that allows antenna 102 to form a single dipole.

[0041] Antenna 102 includes tuning elements 130a and 130b extending from a point along dipole elements 110 and 120, respectively. Tuning elements 130a and 130b are arranged in an open pattern extending from dipole elements 110 and 120. It has been found that tuning elements 130a and 130b provide attenuation of unwanted signals at frequencies from about 2.4 GHz to about 4.0 GHz. In an embodiment, tuning elements 130a and 130b can provide attenuation of unwanted signals at frequencies from about 2.4 GHz to 4.0 GHz by at least 35 dB. In an embodiment, tuning elements 130a and 130b can provide attenuation from about 0 dB to about 40 dB, about 5 dB to about 35 dB, about 10 dB to about 30 db, or about 15 dB to about 25 dB for frequencies from about 2.4 GHz to about 4.0 GHz. In one embodiment, tuning elements 130a and 130b provide attenuation from about 35 dB to about 40 dB for frequencies from about 2.4 GHz to about 4.0 GHz.

[0042] Tuning elements 130a and 130b can be provided at any position along the length of one or both of dipole elements 110 or 120. Tuning elements 130a and 130b are provided by conductive materials connected to dipole elements. In some embodiments, the length and / or shape of tuning elements 130a and 130b are selected as needed to provide a desired attenuation level of signals higher than 2.4GHz. In other embodiments, the length and / or shape of tuning elements 130a and 130b are selected as needed to provide a desired attenuation level of signals within the 2.4GHz to 4.0GHz frequency band. In addition, the length or size of the shape of tuning elements 130a and 130b can vary depending on the position of the tuning elements on the dipole elements. In one embodiment, tuning elements 130a and 130b are arranged at equivalent positions on the corresponding dipole elements and have the same shape and size. In another embodiment, tuning elements 130a and 130b are placed at different positions relative to each other on the corresponding dipole elements and can have the same or different shapes and sizes different from each other. In an embodiment, tuning elements 130a and 130b may have an "L" shape consisting of a short leg and a long leg. The short leg of the "L" shape is connected to the corresponding dipole elements 110 and 120, and the long leg extends vertically away from the short leg.

[0043] In an embodiment, the shape and position of the tuning elements 130a and 130b can be set to provide a desired attenuation level of signals within the 2.4 GHz to 4.0 GHz frequency band. In an embodiment, the shape and position of the tuning elements 130a and 130b can be set to provide a desired attenuation level of signals above 2.4 GHz. The tuning elements 130a and 130b can have any shape as needed. The shape can be set to a trace, a solid block element, or any other pattern. The tuning elements 130a and 130b can be set to a geometric shape, such as but not limited to a triangle, a rectangle, a circle, an ellipse, a trapezoid, a pentagon, a hexagon, etc. In one embodiment, when the tuning elements 130a and 130b are closer to the ends of the dipole elements 110 and 120 (i.e., farther away from the loop area 103 and closer to the pads 130 and 140), the size and / or length of the tuning elements can be reduced.

[0044] The location, shape and / or size of tuning elements 130a and 130b may be evaluated using electromagnetic simulation software. Construction and testing of antenna 102 is then performed to confirm that the antenna shape with tuning elements 130a and 130b provides the desired signal attenuation level within a predetermined frequency range, such as the microwave range.

[0045] will realize that Figures 1A to 1CThe antenna 102 shown is merely an illustrative embodiment of a possible antenna 102. The shape and structure of the antenna 102, such as the configuration of the dipole elements relative to the pattern, the number of undulations, the thickness of the regions, the periodicity of the undulations, etc., can be selected as desired to provide a desired output in the range of 860 MHz and 960 MHz while also achieving a desired level of attenuation of signals above 2.4 GHz or in the frequency band of 2.4 GHz to 4.0 GHz.

[0046] The material selected for the RFID tag 100 of the present invention may be chosen from a range of materials depending upon manufacturing cost, manufacturing yield, performance of the tag in its intended use, environmental factors (besides microwave radiation exposure), and similar considerations.

[0047] RFID tag 100 includes an antenna according to the present technology formed on a substrate 101. The substrate 101 may be selected as desired for any particular purpose or intended application. Examples of suitable substrates include, but are not limited to, paper, paperboard, or polymer substrates such as, for example, polyester terephthalate (PET), polyimide, polyethylene, epoxy or reinforced epoxy, or similar materials.

[0048] RFID antenna 102 can be formed by a conductive material formed on a substrate in a pattern. The conductive pattern can be formed by any suitable material. Examples of suitable materials include, but are not limited to, copper, aluminum, silver, gold, other metals, or carbon. Antenna 102 can also be printed with a conductive ink that includes a dispersion of silver, gold, or other metals, or particles coated with silver, gold, or other metal conductors, or non-metallic conductors such as carbon or polyaniline. Antenna 102 can be manufactured using commercially available flexible circuits that are produced using processes and designs that have proven to be highly productive. Generally, the higher the conductivity of antenna 102, the greater the current that will be generated in a coil of a specific size during microwave exposure. Generally, the higher the conductivity of antenna 102, the greater the read range of RFID tag 100 for a coil of a specific size.

[0049] The embodiments described herein are applicable to all forms of tags. Tag 100 may also be referred to herein as a tag. A "tag inlay" or "inlay" is defined as an assembled RFID device, which typically includes an antenna and an integrated circuit chip (and / or other electronic circuits) formed on a substrate, and is configured to respond to inquiries. A "tag label" or "tag" is typically defined as an inlay that has been attached to a pressure-sensitive adhesive 105 (PSA) structure, or has been laminated, cut and stacked for application. In one embodiment, inlay 100 is attached to another surface of article 150, or between surfaces of article 150, such as paper, cardboard, etc., for attachment to an article 150 to be tracked (such as clothing items, packaging of meat, etc.).

[0050] The RFID tag 100 of the present invention may optionally be molded or incorporated into various objects, containers or housings or the like.

[0051] What has been described above includes examples of this specification. Of course, it is not possible to describe every conceivable combination of components or methods for the purpose of describing this specification, but one of ordinary skill in the art will recognize that many further combinations and permutations of this specification are possible. Therefore, this specification is intended to cover all such alternatives, modifications and variations that fall within the spirit and scope of the appended claims. In addition, for scopes where the term "comprising" is used in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term "comprising", as interpreted when "comprising" is used as a transitional word in a claim.

[0052] Example

[0053] like Figure 1A As shown, an RFID tag 100 including an RFID antenna 102 is provided. The RFID antenna 102 is formed of an aluminum foil having a thickness of 9 μm on a PET substrate having a thickness of 50 μm. A comparative RFID tag is prepared in a similar manner, which includes Figure 1A The antenna has a similar shape to the RFID antenna, except that the comparative RFID antenna does not include the tuning elements 130a and 130b (see Figure 1B ).

[0054] Antenna 102 is analyzed using an electromagnetic simulator in free space. Figure 2 The conjugate matching factor display of the comparison antenna is shown. The comparison antenna shows matching points at 911 MHz and 1110 MHz, which indicates a good match between the antenna and free space. The comparison antenna also shows another area at 2.8 GHz where the antenna has only 10 dB of rejection of the input signal. When applied near meat products, Figure 2 The response shown is shifted down in frequency by 50 MHz to 200 MHz, with reduced rejection at 2.45 GHz. Additionally, the heat generated by the integrated circuit is sufficient to cause the tag to burn.

[0055] Figure 3 Shown for Figure 1A The conjugate matching factor of the antenna is shown. The antenna shows the matching points within the desired range for RFID operation. Figure 3It is also shown that the suppression of input signals at frequencies from 2.4 GHz to 4 GHz is greater than 35 dB. After adding the tuning element, the original matching point is shifted lower in frequency. The antenna loop area and the height of the meandering dipole element are reduced. This provides matching points at 915 MHz and 1130 MHz.

[0056] The foregoing description identifies various non-limiting embodiments of RFID tags. Modifications may occur to those skilled in the art and those who can make and use the invention. The disclosed embodiments are for illustrative purposes only and are not intended to limit the scope of the invention or the subject matter set forth in the claims.

Claims

1. A dipole antenna for a radio frequency identification tag, the dipole antenna comprising: Loop area; a first dipole element electrically connected to the loop region and terminating at a first pad; a second dipole element electrically connected to the loop region and terminating at a second pad; The first dipole element and the second dipole element extend in directions opposite to each other along a horizontal axis of the dipole antenna; as well as at least one tuning element, wherein the at least one tuning element extends from one or both of the first dipole element and the second dipole element, the shape, size and position of each of the at least one tuning element being selected to obtain a desired attenuation level of signals within a predetermined frequency band, wherein the dipole antenna is tuned using the at least one tuning element to operate within a predetermined operating frequency range.

2. The dipole antenna according to claim 1, wherein: The desired attenuation level of the signal is at least 35 dB.

3. The dipole antenna according to any one of claims 1 to 2, wherein: The predetermined frequency band is greater than 2 GHz, between 2.4 GHz and 4.0 GHz, or between 2 GHz and 14.5 GHz.

4. The dipole antenna according to claim 1, wherein: The at least one tuning element provides a desired attenuation level of 0 dB to about 40 dB, about 5 dB to about 35 dB, about 10 dB to about 30 db, or about 15 dB to about 25 dB for the predetermined frequency band between about 2.4 GHz to about 4.0 GHz.

5. The dipole antenna according to any one of claims 1 to 2, wherein: The at least one tuning element provides a desired attenuation of about 35 dB to about 40 dB for the predetermined frequency band between about 2.4 GHz to about 4.0 GHz.

6. The dipole antenna according to any one of claims 1 to 5, wherein: The shape of the at least one tuning element can be a triangle, rectangle, circle, ellipse, trapezoid, pentagon, hexagon, "L" shape, trace or block; wherein the at least one tuning element can all have the same shape, different shapes or a combination of various shapes.

7. The dipole antenna according to any one of claims 1 to 6, wherein: The first dipole element and the second dipole element each have at least one tuning element of the same size at an equivalent position along the dipole element, wherein the at least one tuning element each extends from the equivalent position and has an "L" shape with a short leg and a long leg; the short leg of the "L" shape is electrically connected to the first dipole element and the second dipole element.

8. The dipole antenna according to any one of claims 1 to 7, wherein: The first dipole element and the second dipole element each have a meander pattern, wherein a physical length of the first dipole element is shorter than an electrical length of the first dipole element, and a physical length of the second dipole element is shorter than an electrical length of the second dipole element.

9. The dipole antenna according to any one of claims 1 to 8, further comprising a circuit chip electrically connected to the loop region using the first connection portion of the loop region and the second connection portion of the loop region, in: The first connection portion and the second connection portion of the loop region are located at a first side of the loop region, and the first dipole element and the second dipole element are electrically connected to the second side of the loop region, the first connection portion and the second connection portion of the loop region are located at a first side of the loop region, and the first dipole element and the second dipole element are electrically connected to the first side of the loop region, or The first connection portion and the second connection portion of the loop region are located at a first side of the loop region, and the first dipole element and the second dipole element are electrically connected at a position between the first side and the second side of the loop region; The first side and the second side of the loop region are located at opposite sides of the loop region.

10. A radio frequency identification (RFID) tag, the RFID tag comprising: a dipole antenna formed on a substrate having an adhesive for attaching the tag to a surface; The dipole antenna has: Loop area; a first dipole element electrically connected to the loop region and terminating at a first pad; a second dipole element electrically connected to the loop region and terminating at a second pad; The first dipole element and the second dipole element extend in directions opposite to each other along a horizontal axis of the dipole antenna; as well as at least one tuning element, wherein the at least one tuning element extends from one or both of the first dipole element and the second dipole element, the shape, size and position of each of the at least one tuning element being selected to obtain a desired attenuation level of signals within a predetermined frequency band, wherein the dipole antenna is tuned using the at least one tuning element to operate within a predetermined operating frequency range.

11. The RFID tag according to claim 10, wherein: The desired attenuation level of the signal is at least 35 dB.

12. The RFID tag according to any one of claims 10 to 11, wherein: The predetermined frequency band is greater than 2 GHz, between 2.4 GHz and 4.0 GHz, or between 2 GHz and 14.5 GHz.

13. The RFID tag according to claim 10, wherein: The at least one tuning element provides a desired attenuation level of 0 dB to about 40 dB, about 5 dB to about 35 dB, about 10 dB to about 30 db, or about 15 dB to about 25 dB for the predetermined frequency band between about 2.4 GHz to about 4.0 GHz.

14. The RFID tag according to any one of claims 10 to 11, wherein: The at least one tuning element provides a desired attenuation of about 35 dB to about 40 dB for the predetermined frequency band between about 2.4 GHz to about 4.0 GHz.

15. The RFID tag according to any one of claims 10 to 14, wherein: The shape of the at least one tuning element can be a triangle, rectangle, circle, ellipse, trapezoid, pentagon, hexagon, "L" shape, trace or block; wherein the at least one tuning element can all have the same shape, different shapes or a combination of various shapes.

16. The RFID tag according to any one of claims 10 to 15, wherein: The first dipole element and the second dipole element each have at least one tuning element of the same size at an equivalent position along the dipole element, wherein the at least one tuning element each extends from the equivalent position and has an "L" shape with a short leg and a long leg; the short leg of the "L" shape is electrically connected to the first dipole element and the second dipole element.

17. The RFID tag according to any one of claims 10 to 16, wherein: The first dipole element and the second dipole element each have a meander pattern, wherein a physical length of the first dipole element is shorter than an electrical length of the first dipole element, and a physical length of the second dipole element is shorter than an electrical length of the second dipole element.

18. The RFID tag according to any one of claims 10 to 17, further comprising: A circuit chip electrically connected to the loop region using the first connection portion of the loop region and the second connection portion of the loop region, in: The first connection portion and the second connection portion of the loop region are located at a first side of the loop region and the first dipole element and the second dipole element are electrically connected to a second side of the loop region; The first connection portion and the second connection portion of the loop region are located at a first side of the loop region and the first dipole element and the second dipole element are electrically connected to the first side of the loop region; or The first connection portion and the second connection portion of the loop region are located at a first side of the loop region, and the first dipole element and the second dipole element are electrically connected at a position between the first side and the second side of the loop region; The first side and the second side of the loop region are located on opposite sides of the loop region.

19. An article, comprising: an article and a radio frequency identification (RFID) tag attached to the article; The RFID tag comprises: a dipole antenna formed on a substrate having an adhesive for attaching the tag to a surface; The dipole antenna has: Loop area; a first dipole element electrically connected to the loop region and terminating at a first pad; a second dipole element electrically connected to the loop region and terminating at a first pad; The first dipole element and the second dipole element extend in directions opposite to each other along a horizontal axis of the dipole antenna; and at least one tuning element, wherein the at least one tuning element extends from one or both of the first dipole element and the second dipole element, the shape, size, and position of each of the at least one tuning element being selected to obtain a desired attenuation level of signals within a predetermined frequency band, wherein the dipole antenna is tuned to operate within a predetermined frequency range using the at least one tuning element; wherein the desired attenuation level is selected to prevent the RFID tag from thermally damaging the item when the RFID tag is exposed to RF energy exceeding a predetermined power level within the predetermined frequency band.

20. The article of claim 19, wherein: The predetermined power level is greater than +20 dBm and the predetermined frequency band is greater than 2 GHz, or the predetermined power level and the predetermined frequency band are those generated by a microwave oven.

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