Antenna for radio frequency-readable article

Abstract

Aspects in accordance with the present invention pertain to an antenna for an article that is electronically readable responsively to radio frequency (RF) signals. Said antenna comprises a metallic conductive pattern and a carbon conductive pattern. The metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery. Said metallic periphery has a gap that effectively prevents the completion of the metallic loop. The carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture.

Description

[0001] TITLE OF THE INVENTION

[0002] ANTENNA FOR RADIO FREQUENCY-READABLE ARTICLE

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to articles readable responsively to radio frequency (RF) signals and the manufacture of such articles. Particularly, the present invention relates to antennas of such articles and the manufacturing of such antennas.

[0005] BACKGROUND OF THE INVENTION

[0006] Articles which are electronically readable responsively to radio frequency (RF) signals (“RF- readable articles”) find their exemplary applications in radio frequency identification (RFID) which is prevalent in modern access control, payment, and supply chain management systems.

[0007] A conventional RFID system comprises an RFID reader and an RF-readable article. In such a system, the RF-readable article is typically referred to as an “RFID tag.” Regardless, a tag is not its only form: An RF-readable article may as well take any other form, such as a collectible toy, whose special features can be realized in response to a matching RFID reader.

[0008] An RF-readable article comprises a substrate, an antenna, and an integrated circuit (“IC”, typically taking the form of a microchip). These three components are considered bare-minimum to work a conventional RF-readable article: The substrate supports the antenna and the IC; the antenna receives, and electronically responds to, the RF signals; and the IC stores the data to be transmitted to the reader upon a successful reading. Also conventionally, the foregoing components are further covered by or encased in protective and / or adhesive materials for increased utility. RF-readable articles are conventionally classified into those of “passive” and “active” configurations.

[0009] A passive RF-readable article refers to that which does not generate or transmit signals; thus, such an article works only responsively to the reader’s signals. It follows that a passive RF-readable article is conventionally not connected to a power source and operates in a distance from the reader (“reading range”) that is typically within 3 - 15 meters IEEE Access, vol. 9, pp. 63611-63635, 2021; J. Mater. Chem. C, 2023, 11, 406).

[0010] An active RF-readable article refers to that which generates and transmits signals to the reader to initiate the reading process. As such, an active RF-readable article is conventionally connected to a power source and can reach a reading range up to 100 meters (Sensors. 2023; 23(15):6925; Sensors. 2021; 21(9):3138). Further, an active RF-readable article generally has a greater data storage capacity than a passive RF-readable article does.

[0011] The reading range is partly determined by the RF signals’ frequency band. For example, in an RFID system using a passive RF-readable article, the low frequency band (“LF”, exemplarily 125 - 134 kHz) enables a reading range that is within 10 centimeters; the high frequency band (“HF”, exemplarily 13.56 MHz) enables a reading range falling within 10 centimeters and 1 meter; and the ultra-high frequency band (“UHF”, exemplarily 860 - 960 MHz), enables a reading range falling within 3 - 15 meters (J. Mater. Chem. C, 2023, 11, 406).

[0012] The reading range is further determined by the antenna’s design. Conventionally, and particularly in passive RF-readable articles, the antenna is a conductive pattern borne by and fixed upon the substrate. The said “pattern” refers to a conductive material being applied to the substrate’s surface in a predetermined configuration. Usually, the resulting pattern is extremely thin. As such, the conductive material is conventionally conductive printing ink which can effectively bond with the substrate’s surface — in many cases with subsequent treatment, e.g. drying or curing.

[0013] Designing the antenna is a complicated process. The resulting RF reading performance depends on several further factors, including the conductive material’s electrical properties, the substrate’s surface and electrical properties, and the configuration of the pattern itself. Financial and environmental concerns also arise from the consumption of conductive materials, particularly metalbased materials.

[0014] Many prior arts propose many such configurations as well as manufacturing processes. Examples of such prior arts pertaining to passive RF-readable articles are as follows.

[0015] EP 1730809 Al discloses an antenna structure comprising a high effective resistance portion and a low effective resistance portion. The antenna structure is further configured such that the high effective resistance portions are sized and located such that, even if they were to have the same effective resistance as the low effective resistance portions, the high effective resistance portions would have a lower current flow than the low effective resistance portions. This art covers some embodiments that use carbon particles as an alternative to metal particles as a conductive material.

[0016] CN 111682306 A discloses an RFID tag antenna and its preparation method. The said antenna comprises a metal pattern layer and a two-dimensional carbon nanosheet pattern layer.

[0017] US 20230395966A1 discloses an RFID tag including an inlay in which an IC chip and an antenna are provided on a base material having a main surface. The antenna includes a loop conductive portion having both end portions connected to the IC chip so as to form a loop shape through the IC chip, and a dipole antenna portion disposed to surround the loop conductive portion with an interval allowing inductive coupling, and the loop conductive portion and the dipole antenna portion are formed on the main surface to have same thickness based on the main surface, and the IC chip is disposed on both end portions of the loop conductive portion. In some embodiments, the said conductive portions can be formed by printing conductive ink containing metal particles or carbon.

[0018] K Jaakkola et al. 2020, 2D Mater. 7 015019 investigated the performance of “hybrid” antenna structure in a UHF RFID system. The said hybrid antenna was made of few-layer graphene (FLG) flakes and an aluminum loop.

[0019] SUMMARY OF THE INVENTION

[0020] An object of the present invention is to provide an antenna for an RF-readable article which can address the abovementioned technical problems effectively.

[0021] Another object of the present invention is to provide an antenna for an RF-readable article which effectively improves the technical synergy between the metal-based conductive material and carbon-based conductive material featured in such an antenna.

[0022] Yet another object of the present invention is to provide an antenna for an RF-readable article which effectively optimizes the consumption of metal-based conductive material in its preparation or production.

[0023] Further, an object of the present invention is to provide a technique for the preparation and production of such an antenna.

[0024] Furthermore, an object of the present invention is to provide an RF-readable article comprising such an antenna, as well as an RFID system and method involving the use of the said RF-readable article.

[0025] Summarized herein, in a non-limiting manner, are the present invention’s key aspects which illustrate many applications of the present inventive concept. In the first aspect, an embodiment is a substrate bearing an antenna for an article that is electronically readable responsively to radio frequency (RF) signals. Said antenna comprises a metallic conductive pattern and a carbon conductive pattern. The metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery. The said metallic periphery has a gap that effectively prevents the completion of the metallic loop. The carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture.

[0026] Illustratively, an embodiment in the first aspect may be a product from a printing process or sub-process whereby an antenna is applied onto the substrate. Further examples of optional and preferred embodiments in the first aspect will be summarized later.

[0027] In the second aspect, an embodiment is an article that is electronically readable responsively to radio frequency (RF) signals. Said article comprises a substrate bearing an antenna and an integrated circuit (IC). The said antenna comprises a metallic conductive pattern and a carbon conductive pattern. The metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery having a gap. The integrated circuit is attached to the metallic periphery to close the gap, thereby effectively completing the metallic loop. The carbon conductive pattern features one or a plurality of second apertures, at least one of the said second apertures coinciding substantially with the first aperture. And the integrated circuit is free of contact with the carbon conductive pattern.

[0028] Illustratively, an embodiment in the second aspect may be a barely RF-readable article with the IC being attached to the antenna so as to complete the metallic loop and to provide a means for data storage. Further examples of optional and preferred embodiments in the second aspect will be summarized later. Illustratively, an embodiment in the first or second aspect may further comprise any known auxiliary features, such as an adhesive layer, a laminate or similar protective layer, a case or similar shell which may further promote the article’s protection or utility.

[0029] In the third aspect, an embodiment is a radio frequency identification (RFID) system comprising the article according to the second aspect. Illustratively, an embodiment in the third aspect may be such a system, comprising at least one such RF-readable article and a suitable RF- reader.

[0030] In the fourth aspect, an embodiment is a radio frequency identification (RFID) method comprising at least a step of electronically reading the article according to the second aspect. Illustratively, an embodiment in the fourth aspect may be such a method wherein at least one such RF-readable article is read by a suitable RF-reader.

[0031] Illustratively, an embodiment in the third or fourth aspect may be implemented for any suitable purpose, including access control and supply chain management. Further examples of optional and preferred embodiments in the third and fourth aspects will be summarized later.

[0032] In the fifth aspect, an embodiment is a process for preparing, on a substrate, an antenna for an article that is electronically readable responsively to radio frequency (RF) signals. Said process comprises a step of causing the substrate to bear a metallic conductive pattern and a carbon conductive pattern. The said metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery. The said metallic periphery has a gap that effectively prevents the completion of the metallic loop. And the said carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture. Illustratively, an embodiment in the fifth aspect may be a process by which an embodiment in the first aspect is formed. Further examples of optional and preferred embodiments in the fifth aspect will be summarized later.

[0033] In the sixth aspect, an embodiment is a process for producing an article that is electronically readable responsively to radio frequency (RF) signals. Said process comprises a step of attaching an integrated circuit (IC) to a metallic conductive pattern on a substrate. The said substrate bears the said metallic conductive pattern and a carbon conductive pattern. The said metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery. The said metallic periphery has a gap that effectively prevents the completion of the metallic loop. The said carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture.

[0034] Illustratively, an embodiment in the sixth aspect may be a process by which an embodiment in the second aspect is formed. For this reason, it is preferable that the integrated circuit is attached to the metallic periphery to close the gap, thereby effectively completing the metallic loop. It is more preferable that the attachment of the integrated circuit is carried out so that the integrated circuit is free of contact with the carbon conductive pattern. Further examples of optional and preferred embodiments in the sixth aspect will be summarized later.

[0035] In an embodiment according to the second, third, fourth, or sixth aspect, it is preferable that the carbon conductive pattern substantially overlays the metallic conductive pattern except where the integrated circuit is attached thereto. In such an embodiment, it is more preferable that the carbon conductive pattern substantially overlays the metallic periphery except where the integrated circuit is attached thereto. In an embodiment according to any one of the foregoing aspects, the substrate’s surface area is preferably covered substantially more by the carbon conductive pattern than by the metallic conductive pattern.

[0036] In an embodiment according to any one of the foregoing aspects, the ratio of the area covered by the metallic conductive pattern to the area covered by the carbon conductive pattern is preferably within the range of 0.005 - 0.500, or more preferably within the range of 0.005 - 0.375, or even more preferably within the range of 0.01 - 0.20.

[0037] Due to the costs and environmental concerns associated with the use of metallic conductive material, the present inventors favored reducing the consumption of metallic conductive. The present inventors discovered that the said favorable reduction was achieved effectively by an antenna configuration according to the present invention. Further, the present inventors found that, when the substrate’s surface areas covered by the metallic conductive pattern and by the carbon conductive pattern, and / or the ratios of such coverage, are controlled according to a preferred embodiment, such reduction is achieved more effectively while enabling an antenna that is essential to an RF-readable article exhibiting an excellent reading range.

[0038] In an embodiment according to any one of the foregoing aspects, it is preferable that the metallic conductive pattern has a thickness within the range of 5 - 15 pm, or more preferably within the range of 5 - 11 pm. It is also preferable that the carbon conductive pattern has a thickness within the range of 10 - 100 pm, or more preferably within the range of 10 - 80 pm. The present inventors found that the foregoing ranges of thicknesses contributed to a favorable balance of RF-responsive reading performance and conductive material consumption.

[0039] In an embodiment according to any one of the foregoing aspects, the metallic conductive pattern is preferably formed of a silver printing ink or a copper printing ink or a mixture thereof, and the carbon conductive pattern is formed of a carbon printing ink having a sheet resistivity of below 20 Q / sq. In such an embodiment, the said sheet resistivity of the carbon printing ink is more preferably not exceeding 10 Q / sq.

[0040] In an embodiment according to any one of the foregoing aspects, the metallic conductive pattern preferably further comprises a marker configured to locate the attachment of the integrated circuit.

[0041] In an embodiment according to any one of the foregoing aspects, it is preferable that the metallic conductive pattern and the carbon conductive pattern are configured and / or disposed such that the embodiment’s working relies on an electric circuit that is essentially a conductive loop.

[0042] BRIEF DESCRIPTION OF DRAWINGS

[0043] The principle of the present invention and its advantages will become apparent in the following description, taking into consideration the accompanying drawings in which:

[0044] Fig. 1A shows an antenna according to Comparative Example I (not to scale).

[0045] Fig. IB shows an antenna according to Comparative Example II (not to scale).

[0046] Fig. 1C shows an antenna according to Comparative Example III (not to scale).

[0047] Fig. ID shows an antenna according to Comparative Example IV (not to scale).

[0048] Fig. 2A shows Exemplary Embodiment 1 of an antenna according to the present invention (not to scale).

[0049] Fig. 2B shows a schematic diagram of an exemplary process for preparing an antenna of Exemplary Embodiment 1 according to the present invention (not to scale).

[0050] Fig. 2C shows an enlarged view of Exemplary Embodiment 1 of an antenna according to the present invention (not to scale). Fig. 2D shows an enlarged view of Exemplary Embodiment 1 of an antenna having an integrated circuit attached thereupon according to the present invention (not to scale).

[0051] Fig. 3 shows Exemplary Embodiment 2 of an antenna according to the present invention (not to scale).

[0052] Fig. 4 shows Exemplary Embodiment 3 of an antenna according to the present invention (not to scale).

[0053] Fig. 5 shows Exemplary Embodiment 4 of an antenna according to the present invention (not to scale).

[0054] Fig. 6 shows Exemplary Embodiment 5 of an antenna according to the present invention (not to scale).

[0055] Fig. 7 shows Exemplary Embodiment 6 of an antenna according to the present invention (not to scale).

[0056] Fig. 8 shows Exemplary Embodiment 7 of an antenna according to the present invention (not to scale).

[0057] Fig. 9 shows Exemplary Embodiment 8 of an antenna according to the present invention (not to scale).

[0058] Fig. 10 shows Exemplary Embodiment 9 of an antenna according to the present invention (not to scale).

[0059] Fig. 11 shows Exemplary Embodiment 10 of an antenna according to the present invention

[0060] (not to scale).

[0061] DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS It is to be understood that the following detailed description will be directed to embodiments, provided as examples for illustrating the concept of the present invention only. The present invention is in fact not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of this invention will be limited only by the appended claims.

[0062] The detailed description of the invention is divided into various sections only for the reader’s convenience and disclosure found in any section may be combined with that in another section.

[0063] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this invention belongs.

[0064] It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0065] “Comprising” or “comprises” is intended to mean that the compositions and methods include the recited elements, but not excluding others. “Consisting essentially of’ when used to define compositions and methods, shall mean excluding other elements of any essential significance to the combination for the stated purpose. Thus, a device or method consisting essentially of the elements as defined herein would not exclude other materials or steps that do not materially affect the basic and novel characteristic(s) of the claimed invention. “Consisting of’ shall mean excluding more than trace elements of other ingredients and substantial method steps. Embodiments defined by each of these transition terms are within the scope of this invention.

[0066] “Carbon conductive material” refers to a material or composition comprising a significant amount of one or more carbon element and / or carbon-based compound, and whose electrical conductivity is essentially imparted by the said one or more carbon element and / or carbon-based compound. Further, the said “carbon-based compound” includes a micromolecular compound and a macromolecular compound which may be added to the composition.

[0067] “Metallic conductive material” refers to a material or composition comprising a significant amount of a metallic element or metallic compound, and whose electrical conductivity is essentially imparted by the said metallic element or metallic compound.

[0068] “Coincide substantially”, when used relative to apertures, gaps, holes, spaces, clearances, or the like (“apertures, etc.”), refers to an alignment of two or more such apertures, etc., in a way that (a) the apertures, etc., are disposed substantially concentrically, or (b) when the apertures, etc., are of different sizes, an object passing through the smaller aperture will always pass through the larger aperture.

[0069] A “substrate bearing the antenna” is not limited to the “final” substrate upon which the antenna is meant to be permanently fixed, and which is intended to be part of the RF-readable article. Rather, said substrate is inclusive of an “intermediate” substrate, e.g. a decal or like, upon which the antenna is meant to be temporarily fixed, and from which the antenna may be transferred further to the “final” substrate upon which the antenna is meant to be permanently fixed, and which is intended to be eventually part of the RF-readable article. The substrate is preferably a sheet material and is also preferably an electrically resistive material. Examples of substrate materials which are applicable to an embodiment include polyethylene terephthalate (PET) and paper, among other known materials.

[0070] “Reading” refers to a mechanism in the context of RF technology. Particularly, the term refers to a process by which an RF reader detects and interprets data stored in an RF-readable article. “Reading range” refers to a maximum distance at which an RF reader can successfully read and / or communicate electronically with an RF-readable article at a certain frequency.

[0071] Fig. 1A - ID shows four Comparative Examples I - IV, whose details are described below and whose makings and performances are to be described in comparison with Exemplary Embodiments further in this specification.

[0072] According to Fig. 1A, Comparative Example I is an antenna 100 comprising a carbon conductive pattern 120 alone. The carbon conductive pattern 120 further comprises an aperture 122, which in this comparative example is of a substantially rectangular shape. Here, the said aperture 122 is substantially enclosed by a carbon periphery 124. Further, a gap 126 is provided by the carbon periphery’s 124 obliquely opposing corners of two step-tapered ends 127 that protrude and recede in uncontacted corresponding shapes. The carbon conductive pattern 120 of Comparative Example I is configured such that, when an integrated circuit (not shown in Fig. 1A) is attached onto the antenna 100, the center of that integrated circuit and the gap 126 substantially coincide, and two corners of that integrated circuit are disposed substantially upon the said two opposing corners of the two step-tapered ends 127.

[0073] According to Fig. IB, Comparative Example II is also an antenna 100 comprising a carbon conductive pattern 120 alone. Here, the aperture 122 is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. Further to the aperture 122, Comparative Example II comprises main features which are apparent and labeled on Fig. IB. Configurations of the said remaining main features of Comparative Example II are substantially in accordance with those of Comparative Examples I; thus, their detailed description is omitted for brevity. According to Fig. 1C, Comparative Example III is an antenna 100 comprising a metallic conductive pattern a 110 and a carbon conductive pattern 120. Here, the metallic conductive pattern 110 is a pair of separate metallic bands 114, substantially rectangular strips disposed along a pair of substantially parallel alignments. The metallic bands’ 114 obliquely opposing flat ends 115 have opposing corners interposed by a gap 116.

[0074] The metallic conductive pattern 110 of Comparative Example III further comprises IC attachment markers 118, shaped substantially as a pair of square islands, disposed obliquely across the gap 116. The metallic conductive pattern 110 of Comparative Example III is configured such that, when an integrated circuit (not shown in Fig. IC) is attached onto the antenna 100, the center of that integrated circuit and the gap 116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said two corners of the two flat ends 115 and upon the two IC attachment markers 118.

[0075] The carbon conductive pattern 120 of Comparative Example III overlays the metallic conductive pattern 110 (whose overlaid parts are represented in Fig. IC as broken lines). The carbon conductive pattern 120 further comprises an aperture 122 which in this comparative example is of a substantially rectangular shape. Here, the said aperture 122 is substantially enclosed by a carbon periphery 124. The aperture 122 is further connected to an IC attachment slot 128 which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 120.

[0076] According to Fig. ID, Comparative Example IV is an antenna 100 comprising a metallic conductive pattern a 110 and a carbon conductive pattern 120.

[0077] Similarly to Comparative Example III, Comparative Example IV’ s metallic conductive pattern 110 is a pair of separate metallic bands 114, substantially rectangular strips disposed along a pair of substantially parallel alignments. The metallic bands’ 114 obliquely opposing flat ends 115 have opposing corners interposed by a gap 116.

[0078] Unlike Comparative Example III, however, Comparative Example IV’ s metallic bands 114 have substantially greater lengths along the said substantially parallel alignments; across their flat ends 115, the metallic bands’ 114 other ends terminate substantially farther away from the edges of the carbon periphery 124.

[0079] Unlike the foregoing Comparative Examples I - III, Comparative Example IV features no IC attachment marker. Accordingly, the metallic conductive pattern 110 of Comparative Example IV is configured such that, when an integrated circuit (not shown in Fig. ID) is attached onto the antenna 100, the center of that integrated circuit and the gap 116 substantially coincide, two corners of that integrated circuit are disposed substantially upon the said two corners of the two flat ends 115, and the other two corners of that integrated circuit are free from contact. Regardless, the electrical circuit required for RF reading is effectively formed.

[0080] The carbon conductive pattern 120 of Comparative Example IV overlays the metallic conductive pattern 110 (whose overlaid parts are represented in Fig. ID as broken lines). The carbon conductive pattern 120 further comprises an aperture 122 that is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. Here, the said aperture 122 is substantially enclosed by a carbon periphery 124. The aperture 122 is further connected to an IC attachment slot 128 which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 120.

[0081] Next, Fig. 2A shows Exemplary Embodiment 1 of an antenna according to the present invention. In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing corners of obliquely opposing step- tapered ends 1117 of the metallic periphery 1114 that protrude and recede in uncontacted corresponding shapes. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 2A), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said two corners of the metallic periphery’s 1114 step-tapered ends 1117 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0082] Here, the carbon conductive pattern 1200 features a row of five second apertures 1212. The said five second apertures 1212 are separated by four inter-aperture lanes 1214. Each of the said first aperture 1112 and the said second apertures 1212 are bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. All of them 1112, 1212 are of a substantially same size in this embodiment. One of the said second apertures 1212 is the connective second aperture 1212A, which coincides substantially with the first aperture 1112. In this embodiment, the connective second aperture 1212A is the middle second aperture among the five second apertures 1212 in the row. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0083] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 2A represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e., hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 2A) is to be attached thereto.

[0084] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: that which is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is not uniform throughout: The said metallic periphery’s 1114 width adjoining the first aperture’s 1112 straight sides are constrained by the size of the inter- aperture lanes 1214 and thus is incidentally narrower than the width of the other parts of the metallic periphery 1114. Further, the said width is configured so that a significant part of the metallic periphery’s 1114 outer edge 1114B terminates substantially at the outer edges of the carbon conductive pattern 1200, except, of course, about where the integrated circuit is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern

[0085] 1200.

[0086] The antenna 1000 according to Fig. 2A is borne by a substrate (not shown in Fig. 2A). The substrate according to the present invention’s concept may have a surface area that is substantially equal to or larger than the area of the antenna 1000.

[0087] Fig. 2B shows a schematic diagram of an exemplary process for preparing an antenna of Exemplary Embodiment 1 according to the present invention.

[0088] According to this embodiment, an antenna 1000 is prepared on the substrate 10 by first causing the substrate 10 to bear a metallic conductive pattern 1100, and then causing the substrate 10 to bear further a carbon conductive pattern 1200. Here, the configurations of the foregoing conductive patterns 1100, 1200 are in accordance with the description related to Fig. 2A, and thus their descriptions are omitted for brevity. This schematic diagram is applicable to the preparation of any antenna according to the present invention, including all such antennas to be described further below.

[0089] Fig. 2C shows an enlarged view of Exemplary Embodiment 1 of an antenna according to the present invention. The antenna 1000 according to Fig. 2C comprises the same features and configurations as the one shown previously in Fig. 2A, the descriptions of such features and configurations being omitted here for brevity. Particularly, Fig. 2C shows an enlarged view about the metallic conductive pattern’s 1100 metallic loop 1110 and the carbon conductive pattern’s 1200 connective second aperture 1212A. In this view, the metallic conductive pattern’s 1100 gap 1116 and IC attachment markers 1118 are more apparent.

[0090] Fig. 2D further shows an enlarged view of Exemplary Embodiment 1 of an antenna having an integrated circuit (IC) attached thereupon according to the present invention. This view particularly represents an embodiment in which the antenna 1000 has been applied, preferably permanently or semi-permanently, onto a “final” substrate 10, intended to be part of an RF-readable article. As such, the areas underlying the apertures 1112, 1212, 1212A and the IC attachment slot 1216 that is not covered by any part of the metallic conductive pattern 1100 or the carbon conductive pattern 1200, are the areas of the substrate 10. The substrate 10 likewise underlies the gap (hidden from the view of Fig. 2D). Here, the integrated circuit (IC) 20 is attached to the antenna 1000 according to a preferred embodiment, the IC’s 20 four corners being disposed substantially upon the two corners of the tapered ends 1117 and the two IC attachment markers 1118, effectively completing the metallic loop 1110. It should be noted that the disposition of the substrate 10 relative to the antenna 1000 and its features, and the attachment of the IC 20 upon the antenna 10 shown in Fig. 2D, apply as well to other embodiments according to the present invention. Such an applicability is irrespective of whether the metallic periphery’s 1110 ends are tapered, flat, or bent, a combination thereof, or formed in a different configuration, and irrespective of whether the substrate is “intermediate” or “final”.

[0091] Next, Fig. 3 shows Exemplary Embodiment 2 of an antenna according to the present invention.

[0092] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing corners of obliquely opposing bent end 1115 and flat end 1119 of the metallic periphery 1114 that protrude and recede in uncontacted corresponding shapes. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 3), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 bent end 1115 and flat end 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0093] Here, the carbon conductive pattern 1200 features one second aperture 1212 which is also the connective second aperture 1212A. The said connective second apertures 1212A is located substantially in the center of the antenna 1000. Each of the first aperture 1112 and the connective second aperture 1212A is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. All of them 1112, 1212A are of a substantially same size in this embodiment. Moreover, the connective second aperture 1212A coincides substantially with the first aperture 1112. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0094] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 3 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 3) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0095] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: that which is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is not uniform throughout, albeit in a variation from the embodiment shown previously in Fig. 2: Here, there is no inter-aperture lane by which the metallic periphery’s 1114 width may be constrained; thus in Exemplary Embodiment 2, the width adjoining the first aperture’s 1112 straight sides is incidentally broader than the width of the other parts of the metallic periphery 1114. Further, unlike Exemplary Embodiment 1 , the said width in Exemplary Embodiment 2 is configured so that a significant part of the metallic periphery’s 1114 outer edge 1114B substantially recedes from the outer edge of the carbon conductive pattern 1200 except where such an outer edge 1114B connects to the bent end 1115 having one of the corners required to form the gap 1116.

[0096] Furthermore, Fig. 4 shows Exemplary Embodiment 3 of an antenna according to the present invention.

[0097] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110.

[0098] In this embodiment, the said gap 1116 is provided by opposing corners of obliquely opposing step- tapered ends 1117 of the metallic periphery 1114 that protrude and recede in uncontacted corresponding shapes. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 4), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said two corners of the metallic periphery’s 1114 step-tapered ends 1117 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0099] Here, the carbon conductive pattern 1200 features a row of five second apertures 1212. The said five second apertures 1212 are separated by four inter-aperture lanes 1214. Each of the said first aperture 1112 and the said second apertures 1212 are of a substantially rectangular shape. All of them 1112, 1212 are of a substantially same size in this embodiment. One of the said second apertures 1212 is the connective second aperture 1212A, which coincides substantially with the first aperture 1112. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0100] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 4 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 4) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0101] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: both are rectangular. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. The said width is constrained by the size of inter-aperture lanes 1214, and such width is applied to all sides, including to a side where such a dimensional constraint is not present (i.e., the “upper” side in the perspective of Fig. 4). In this embodiment, the said width corresponds with the depth (D) of the IC attachment slot 1216; thus, the metallic periphery’s 1114 outer edge 1114B terminates substantially at the outer edge of the carbon conductive pattern 1200 that adjoins the IC attachment slot 1216.

[0102] Fig. 5 shows Exemplary Embodiment 4 of an antenna according to the present invention.

[0103] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing corners of obliquely opposing step- tapered end 1117 and flat end 1119 of the metallic periphery 1114 that protrude and recede in uncontacted corresponding shapes. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 5), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 step-tapered end 1117 and flat end 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0104] Here, the carbon conductive pattern 1200 features one second aperture 1212 which is also the connective second aperture 1212A. The said connective second apertures 1212A is located substantially in the center of the antenna 1000. Each of the first aperture 1112 and the connective second aperture 1212A is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. All of them 1112, 1212A are of a substantially same size in this embodiment. Moreover, the connective second aperture 1212A coincides substantially with the first aperture 1112. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0105] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 5 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 5) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0106] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take substantially different shapes: The inner edge 1114A is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs, whereas the outer edge 1114B is substantially elliptical. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is not uniform throughout, and there is no inter-aperture lane by which the metallic periphery’s 1114 width may be constrained. In Exemplary Embodiment 4, the inner edge’s 1114A straight sides are disposed substantially along the outer edge’s 1114B major axis, making the corresponding width broader than the width respective to the inner edge’s 1114A arced sides which is disposed substantially along the outer edge’s 1114B minor axis. Further, the said width in Exemplary Embodiment 4 is configured such that the metallic periphery’s 1114 edges substantially recede from the outer edges of the carbon conductive pattern 1200 except where such an edge of the metallic periphery 1114 connects to the one step-tapered end 1117 having one of the corners required to form the gap 1116.

[0107] Fig. 6 shows Exemplary Embodiment 5 of an antenna according to the present invention. In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing, uncontacted corners of obliquely opposing flat ends 1119 of the metallic periphery 1114. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 6), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 flat ends 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0108] Here, the carbon conductive pattern 1200 features one second aperture 1212 which is also the connective second aperture 1212A. The said connective second apertures 1212A is located substantially in the center of the antenna 1000. Each of the first aperture 1112 and the connective second aperture 1212A is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. In this embodiment, the two obliquely disposed flat ends 1119 make the first aperture 1112 slightly yet significantly larger than the connective second aperture 1212A; regardless, the connective second aperture 1212A coincides substantially with the first aperture 1112 according to the concept of the present invention, as they 1112, 1212A are disposed substantially concentrically, and a hypothetical object passing through the smaller connective second aperture 1212A would always pass through the larger first aperture 1112. This embodiment illustrates that the present inventive concept does not require the first aperture and the second aperture to correspond in their size or geometry, provided that they coincide substantially. By the same token, neither the first aperture nor the second aperture is required to be symmetric. A later exemplary embodiment herein will illustrate that in an embodiment comprising multiple apertures of same type, such apertures do not need to be of the same size or geometry. Anyhow, here, the said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0109] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 6 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 6) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0110] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: that which is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. Here, there is no inter-aperture lane by which the metallic periphery’s 1114 width may be constrained. Further, the said width in Exemplary Embodiment 5 is configured so that a significant part of the metallic periphery’s 1114 outer edge 1114B substantially recedes from the outer edge of the carbon conductive pattern 1200.

[0111] Fig. 7 shows Exemplary Embodiment 6 of an antenna according to the present invention.

[0112] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing, uncontacted corners of obliquely opposing flat ends 1119 of the metallic periphery 1114. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 7), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 flat ends 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0113] Here, the carbon conductive pattern 1200 features a row of three second apertures 1212. The said three second apertures 1212 are separated by two inter-aperture lanes 1214. One of the said second apertures 1212 is the connective second aperture 1212A, which is located substantially in the center of the antenna 1000 and coincides substantially with the first aperture 1112. All of them 1112, 1212, 1212A are of substantially rectangular shapes. In this embodiment, however, only the first aperture 1112 and the connective second aperture 1212A have substantially corresponding dimensions. The other two second apertures 1212 have different dimensions, making those two second apertures 1212 larger than the first aperture 1112 and the connective second aperture 1212A. In this embodiment, the two obliquely disposed flat ends 1119 make the first aperture 1112 slightly yet significantly larger than the connective second aperture 1212A; regardless, the connective second aperture 1212A coincides substantially with the first aperture 1112 according to the concept of the present invention, as they 1112, 1212A are disposed substantially concentrically, and a hypothetical object passing through the smaller connective second aperture 1212A would always pass through the larger first aperture 1112. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0114] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 7 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 7) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0115] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: both are rectangular. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. Despite the presence of the inter-aperture lanes 1211, the said width in this embodiment is not constrained by the size of inter-aperture lanes 1214, and such width is applied to all sides. In this embodiment, the said width is substantially smaller than the depth (D) of the IC attachment slot 1216; thus, the metallic periphery’s 1114 outer edge 1114B terminates substantially away from the outer edge of the carbon conductive pattern 1200 that adjoins the IC attachment slot 1216. To appreciate the scope of the present inventive concept, the foregoing description regarding the width of Exemplary Embodiment 6 (Fig. 7) should be compared with the previous description on a similar feature respective of Exemplary Embodiment 3 (Fig. 4).

[0116] Fig. 8 shows Exemplary Embodiment 7 of an antenna according to the present invention.

[0117] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 whose one side is connected to a metallic fin 1120, which in this embodiment is a stripe of a metallic conductive material extending substantially in a lateral direction along the edges of second apertures 1212. The metallic fin 1120 is preferably formed of the same material which makes up the metallic loop 1110 and is preferably formed substantially integrally to, and substantially simultaneously as the formation of, the metallic loop 1110. The metallic loop 1110 features a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing corners of obliquely opposing step-tapered ends 1117 of the metallic periphery 1114 that protrude and recede in uncontacted corresponding shapes. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 8), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said two corners of the metallic periphery’s 1114 step-tapered ends 1117 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0118] Here, the carbon conductive pattern 1200 features a row of five second apertures 1212. The said five second apertures 1212 are separated by four inter- aperture lanes 1214. The second apertures 1212 at both ends of the said row have their farthest corners (with respect to the carbon conductive pattern’s 1200 center) aligning substantially alongside the ends of the metallic fins 1120. Each of the said first aperture 1112 and the said second apertures 1212 are of a substantially rectangular shape. All of them 1112, 1212 are of a substantially same size in this embodiment. One of the said second apertures 1212 is the connective second aperture 1212A, which is disposed substantially at the center of the carbon conductive pattern 1200 and coincides substantially with the first aperture 1112. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200. Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 8 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 8) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0119] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: both are rectangular. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. The said width is constrained by the size of inter-aperture lanes 1214, and such width is applied to all sides, except the “upper” side in the perspective of Fig. 8 where the metallic loop 1110 is connected to the metallic fin 1120. In this embodiment, the said width corresponds with the depth (D) of the IC attachment slot 1216; thus, the metallic periphery’s 1114 outer edge 1114B terminates substantially at the outer edge of the carbon conductive pattern

[0120] 1200 that adjoins the IC attachment slot 1216. Fig. 9 shows Exemplary Embodiment 8 of an antenna according to the present invention.

[0121] Exemplary Embodiment 8 is a close variation of Exemplary Embodiment 5 (Fig. 6), described fully above, the main difference being in the size of their first apertures.

[0122] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing, uncontacted corners of obliquely opposing flat ends 1119 of the metallic periphery 1114. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 9), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 flat ends 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0123] Here, the carbon conductive pattern 1200 features one second aperture 1212 which is also the connective second aperture 1212A. The said connective second apertures 1212A is located substantially in the center of the antenna 1000. Each of the first aperture 1112 and the connective second aperture 1212A is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. In this embodiment, the first aperture 1112 is significantly larger than the connective second aperture 1212A; regardless, the connective second aperture 1212A coincides substantially with the first aperture 1112 according to the concept of the present invention, as they are disposed substantially concentrically, and a hypothetical object passing through the smaller connective second aperture 1212A would always pass through the larger first aperture 1112. Here, the said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0124] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 9 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 9) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0125] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: that which is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. Here, there is no inter-aperture lane by which the metallic periphery’s 1114 width may be constrained. Further, the said width in Exemplary

[0126] Embodiment 8 is configured so that a significant part of the metallic periphery’s 1114 outer edge 1114B substantially recedes from the outer edge of the carbon conductive pattern 1200.

[0127] Fig. 10 shows Exemplary Embodiment 9 of an antenna according to the present invention. Exemplary Embodiment 9 is a further variation of Exemplary Embodiment 8 (Fig. 9), described fully above, the main difference being in the relative disposition of their first apertures and the configuration of their carbon conductive patterns.

[0128] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing, uncontacted corners of obliquely opposing flat ends 1119 of the metallic periphery 1114. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 10), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 flat ends 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0129] Here, the carbon conductive pattern 1200 features one second aperture 1212 which is located substantially in the center of antenna 1000. Each of the first aperture 1112 and the second aperture 1212 is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. In this embodiment, the first aperture 1112 is significantly larger than the second aperture 1212; regardless, the second aperture 1212 coincides substantially with the first aperture 1112 according to the concept of the present invention, as a hypothetical object passing through the smaller second aperture 1212 would always pass through the larger first aperture 1112, even though they 1112, 1212 are not disposed concentrically. The carbon conductive pattern 1200 further comprises an IC attachment slot 1216, which in this embodiment is isolated from the second aperture 1212. Here, the said IC attachment slot 1216 is a which is a substantially rectangular open space that is trilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0130] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 10 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 10) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0131] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: that which is bounded by a pair of opposing substantially straight sides and by a pair of opposing substantially semicircular arcs. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. Here, there is no inter-aperture lane by which the metallic periphery’s 1114 width may be constrained. Further, an edge of one flat end 1119 coincides with the inner edge of the IC attachment slot 1216, whereas an edge of another flat end 1119 coincides with an outer corner of the IC attachment slot 1216. It is further shown in Fig. 10 that the widths of two flat ends 1119 plus the distance across the gap 1116 is substantially equivalent to the depth (D) of the IC attachment slot 1216 in this embodiment.

[0132] Fig. 11 shows Exemplary Embodiment 10 of an antenna according to the present invention. Exemplary Embodiment 10 is a further variation of previously described embodiments, the main difference being the disposition of the first aperture and second aperture relative to the whole antenna.

[0133] In this embodiment, an antenna 1000 comprises a metallic conductive pattern 1100 and a carbon conductive pattern 1200. The metallic conductive pattern comprises a metallic loop 1110 featuring a first aperture 1112 substantially enclosed by a metallic periphery 1114. The said metallic periphery 1114 has a gap 1116 that effectively prevents the completion of the metallic loop 1110. In this embodiment, the said gap 1116 is provided by opposing, uncontacted corners of obliquely opposing flat ends 1119 of the metallic periphery 1114. In this embodiment, the metallic conductive pattern 1100 further comprises IC attachment markers 1118. To locate the attachment of an integrated circuit (not shown in Fig. 11), the IC attachment markers 1118 are shaped substantially as a pair of square islands, disposed obliquely across the gap 1116. Further, the said metallic conductive pattern 1100 is configured such that, when an integrated circuit is attached onto the antenna 1000, the center of that integrated circuit and the gap 1116 substantially coincide, and four corners of that integrated circuit are disposed substantially upon the said corners of the metallic periphery’s 1114 flat ends 1119 and upon the two IC attachment markers 1118. In this way, when the integrated circuit is attached, the metallic loop 1110 is to be completed effectively.

[0134] Here, the carbon conductive pattern 1200 features one second apertures 1212 which is also a connective second aperture 1212A which coincides substantially with the first aperture 1112. All of them 1112, 1212A are of substantially rectangular shapes and are located substantially below (in the perspective of Fig. 11) the center of the antenna 1000. In this embodiment, the two obliquely disposed flat ends 1119 make the first aperture 1112 slightly yet significantly larger than the connective second aperture 1212A; regardless, the connective second aperture 1212A coincides substantially with the first aperture 1112 according to the concept of the present invention, as they 1112, 1212A are disposed substantially concentrically, and a hypothetical object passing through the smaller connective second aperture 1212A would always pass through the larger first aperture 1112. The said connective second aperture 1212A is further connected to an IC attachment slot 1216, which is a substantially rectangular open space that is bilaterally bounded by the respective parts of the carbon conductive pattern 1200.

[0135] Further, in this embodiment, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100. Here, the carbon conductive pattern 1200 also substantially overlays the metallic periphery 1114. Fig. 11 represents part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is overlaid thus (i.e. hidden from the view) as broken lines while representing part of the metallic conductive pattern’s 1100 (and incidentally part of the metallic periphery’s 1114) that is not overlaid thus (i.e., exposed in the view) as solid lines. In this way, the carbon conductive pattern 1200 substantially overlays the metallic conductive pattern 1100 (and incidentally the metallic periphery 1114) except about the gap 1116 and about the IC attachment markers 1118, where the integrated circuit (not shown in Fig. 11) is to be attached thereto. In this way, when the integrated circuit is attached, the said integrated circuit will be free of contact with the carbon conductive pattern 1200.

[0136] Also in this embodiment, the metallic periphery’s 1114 inner edge 1114A (i.e., that which defines the first aperture 1112) and outer edge 1114B (i.e., that which is disposed across the inner edge 1114A) take a substantially similar shape: both are rectangular. The metallic periphery’s 1114 width (W) (i.e., the distance between the inner edge 1114A and the outer edge 1114B) is substantially uniform throughout. Here, there is no inter-aperture lane by which the metallic periphery’s 1114 width may be constrained. Further, the said width in Exemplary Embodiment 10 is configured so that a significant part of the metallic periphery’s 1114 outer edge 1114B substantially recedes from the outer edge of the carbon conductive pattern 1200. In this embodiment, the said width is substantially smaller than the depth (D) of the IC attachment slot 1216; thus, the metallic periphery’s 1114 outer edge 1114B terminates substantially away from the outer edge of the carbon conductive pattern 1200 that adjoins the IC attachment slot 1216.

[0137] EXPERIMENTS

[0138] In all the experiments, the following general description applies.

[0139] An antenna according to a certain Comparative Example or Exemplary Embodiment was prepared upon a substrate by a screen-printing process which caused the substrate to bear the metallic conductive patterns and / or the carbon conductive patterns according to embodiments. Then an integrated circuit (IC) was attached upon the said antenna on the said substate in order to form an article that was electronically readable responsively to radio frequency (RF) signals according to the present invention. All substrates used were commercially prevalent. The substrate materials were varied. Their details are to be described further below.

[0140] In the exemplary screen-printing process, the metallic conductive patterns were formed of a metallic conductive material, specifically silver ink; the carbon conductive patterns were formed of a carbon conductive material, which was either a water-based carbon ink (“W-carbon ink”) or a solvent-based carbon ink (“S-carbon ink”).

[0141] The exemplary sliver ink was a commercial product which contained 70 - 75 wt. % solid silver particles. After being dried at 120 °C for 5 minutes, the said ink’s sheet resistivity was lower than 0.012 Q / sq. Further, the said ink exhibited the viscosity of 9 - 12 Pa-s at 25 °C.

[0142] The exemplary W-carbon ink was prepared by mixing 5 - 7 wt. % of graphene, 0.5 - 1.2 % of a conductive polymer such as polythiophene or polyaniline, 1 -2 wt. % of an ink filler comprising a dispersing agent (TEGO® from Evonik), a wetting agent (Sunfynol® from Evonik), and a surfactant (Tritron™ X-100 from Sigma- Aldrich), with a balance of water purified by a Milli-Q® system. The said mixture was then stirred by an IKA™ EUROSTAR 40 Digital overhead stirrer at 900 - 1,000 RPM for 30 minutes. The resulting W-carbon ink exhibited the sheet resistivity of 2 - 5 Q / sq at 25 °C when measured using a Jandel™ RM3000+ four-point probe resistivity measurement device and exhibited the viscosity of 2.5 - 15 Pa-s at 25 °C and the shear rate of 5 s1when measured using an Anton Paar™ cone-and-plate viscometer.

[0143] The exemplary S-carbon ink was prepared by mixing 33 grams of carbon material with 67 grams of solvent. The said carbon material consisted of 81 wt. % of graphite and 19 wt. % of carbon black; the said solvent consisted of 80 wt. % of a dibasic ester DBE™ procured from Civic Chemical LP and 20 wt. % of VINNOL®, a commercial binder procured from Wacker Chemie AG. Then the said mixture was ground using a three-roll mill running at 80 - 120 RPM; the grinding was set to terminate when the mixture reached a fineness in the range of 7 - 10 pm. The resulting S-carbon ink exhibited the sheet resistivity of 6 - 15 / sq at 25 °C when measured using a Jandel™ RM3000+ four-point probe resistivity measurement device and exhibited the viscosity of 2 - 7 Pa- s at 25 °C and the shear rate of 50 s1when measured using an Anton Paar™ cone-and-plate viscometer.

[0144] The exemplary screen-printing process was carried out semi-automatically with an ATMA® AT-60FA printing machine.

[0145] In an experiment wherein the antenna comprised a carbon conductive pattern alone (i.e., Experiments I - II) the substrate was a substantially rectangular polyethylene terephthalate (PET) sticker sheet having dimensions of about 148 x 210 millimeters (i.e., the A5 paper size). The carbon ink was printed to fully cover one side of the said substrate. Then the substrate was dried in an oven at 100 °C for 25 minutes. Further, the dried carbon ink was selectively removed from the substrate by using a laser cutting machine to form the intended carbon conductive pattern.

[0146] In an experiment wherein the antenna comprised both a metallic conductive pattern and a carbon conductive pattern (i.e., Experiments III and 1 - 10), the substrate, having substantially rectangular dimensions of about 297 x 420 millimeters (i.e., the A3 paper size), was either a plain PET sheet or a plain 180-gram paper sheet. In such an experiment, screen-printing of the metallic conductive pattern was preferably carried out first, followed by screen-printing of the carbon conductive pattern. Particularly, the printing process in such a case started with screen-printing the above-described silver ink onto the substrate by using a polyester screen block with a 100T mesh and using a 10- m thick emulsion, the said emulsion being SAATIGRAF CTS™. The substrate, now bearing metallic conductive pattern, was further subjected to curing at 110 °C for 10 minutes. Then the above-described carbon ink was screen-printed onto the substrate by using a polyester screen block with a 47T mesh and using a 40- m thick emulsion, said emulsion being TEXTIL PHW™ for W-carbon ink, or SAATIGRAF CTS™ for S-carbon ink. The substrate, then bearing both the underlying metallic conductive pattern and the overlying carbon conductive pattern, was further subjected to drying at 130 °C for 10 minutes.

[0147] The resulting antenna’s key dimensions were measured and recorded. Its overall dimensions were measured by a precision ruler; the thickness of its metallic and / or carbon conductive pattern was measured by a Mitutoyo® digital thickness gauge, and the width of its gap (116 of a Comparative Example or 1116 of an Exemplary Embodiment) was measured by an OLYMPUS® optical microscope. Further, the area covered by each conductive pattern (where applicable) was determined using CST Studio Suite™ simulation software.

[0148] The IC was attached to the respective antenna’s designated site using anisotropically conductive adhesives. After the attachment, the image shown in Fig. 2D, described above, serves as an illustrative reference on the positioning of the IC relative to the gap and the IC attachment markers (if any), among other neighboring components. The said positional reference applies to all the experiments, in each of which Higgs® 3 RFID chip was selected as the exemplary IC. Notably, the IC attachment markers (118 in Fig. IC; 1118 in Figs. 2A - 2C and 3 - 8) were configured to support (i.e., stabilize) the attachment of Higgs® 3 RFID chip. Depending on the incidental nature of the IC, an IC attachment marker may be configured differently or removed from the respective antenna. Anyway, an RF -readable article was accordingly formed, ready for the performance test.

[0149] Subsequently, the RF-readable article’s key performance (i.e., the reading range) was measured according to IS018000-6C standard in an anechoic chamber at frequencies of 800 - 1000 MHz using VOYANTIC™ Hand Carry Kit UHF. The results were tabulated and compared.

[0150] Further specific details of each experiment are described as follows. Experiment I. The antenna was in accordance with Comparative Example I (Fig. 1 A) which comprised a carbon conductive pattern alone, screen-printed on the substrate which was a PET sticker sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 75 - 85 pm. Its gap (126 on Fig. 1A) was 200 - 350 pm wide. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming a comparative RF -readable article. The article exhibited a reading range of 1.5 - 1.9 m.

[0151] Experiment II. The antenna was in accordance with Comparative Example II (Fig. IB) which also comprised a carbon conductive pattern alone. The details on the substrate, the carbon conductive material used, the resulting antenna’s overall thickness and overall dimensions, as well as the width of its gap (126 on Fig. IB), followed Experiment I. The IC was likewise attached, forming a comparative RF-readable article which exhibited a reading range of 2.0 - 3.0 m.

[0152] Experiment III. The antenna was in accordance with Comparative Example III (Fig. IC) which comprised a metallic conductive pattern and a carbon conductive pattern, screen-printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 7 - 11 pm for the metallic conductive pattern and 20 - 30 pm for the carbon conductive pattern. Its gap (116 on Fig. IC) was 200 - 350 pm wide. On the substrate, the ratio (AM / Ac) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.010. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming a comparative RF-readable article. The article exhibited a reading range of 3.0 - 3.3 m. Experiment 1. The antenna was in accordance with Exemplary Embodiment 1 (Fig. 2A) which comprised a metallic conductive pattern and a carbon conductive pattern, screen-printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 5 - 11 pm for the metallic conductive pattern and 20 - 30 pm for the carbon conductive pattern. Its gap (1116 on Fig. 2 A) was 200 - 250 pm wide. On the substrate, the ratio (AM / Ac) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.180. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 7.0 - 8.5 m.

[0153] Experiment 2. The antenna was in accordance with Exemplary Embodiment 2 (Fig. 3) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had details of its overall dimensions, overall thicknesses of the metallic conductive pattern and of the carbon conductive pattern, and the gap’s (1116 on Fig. 3) width, which followed Experiment 1. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.120. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 5.5 - 6.5 m.

[0154] Experiment 3. The antenna was in accordance with Exemplary Embodiment 3 (Fig. 4) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had details of its overall dimensions, overall thicknesses of the metallic conductive pattern and of the carbon conductive pattern, and the gap’s (1116 on Fig. 4) width, which followed Experiment 1. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.120. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 4.0 - 5.0 m.

[0155] Experiment 4. The antenna was in accordance with Exemplary Embodiment 4 (Fig. 5) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had details of its overall dimensions, overall thicknesses of the metallic conductive pattern and of the carbon conductive pattern, and the gap’s (1116 on Fig. 5) width, which followed Experiment 1. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.160. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 5.5 - 6.5 m.

[0156] Experiment 5. The antenna was in accordance with Exemplary Embodiment 5 (Fig. 6) which comprised a metallic conductive pattern and a carbon conductive pattern, screen-printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 5 - 11 pm for the metallic conductive pattern and 15 - 25 pm for the carbon conductive pattern. Its gap (1116 on Fig. 6) was 200 - 250 pm wide. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.030. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 4.0 - 5.0 m.

[0157] Experiment 6. The antenna was in accordance with Exemplary Embodiment 6 (Fig. 7) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 7 - 11 pm for the metallic conductive pattern and 25 - 40 pm for the carbon conductive pattern. Its gap (1116 on Fig. 7) was 200 - 250 pm wide. On the substrate, the ratio (AM / Ac) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.050. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 5.5 - 6.8 m.

[0158] Experiment 7. The antenna was in accordance with Exemplary Embodiment 2 (Fig. 3) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. In contrast to Experiment 2, the carbon conductive material was S-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 5 - 10 pm for the metallic conductive pattern and 50 - 60 pm for the carbon conductive pattern. Its gap (1116 on Fig. 3) was 200 - 250 pm wide. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.120. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF -readable article. The article exhibited a reading range of 5.0 - 6.0 m.

[0159] Experiment 8. The antenna was in accordance with Exemplary Embodiment 5 (Fig. 6) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. In contrast to Experiment 5, the carbon conductive material was S-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 5 - 11 pm for the metallic conductive pattern and 55 - 65 pm for the carbon conductive pattern. Its gap (1116 on Fig. 6) was 200 - 250 pm wide. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.030. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF -readable article. The article exhibited a reading range of 4.0 - 5.0 m.

[0160] Experiment 9. The antenna was in accordance with Exemplary Embodiment 1 (Fig. 2A) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate. In contrast to Experiment 1, the substrate here was a plain 180-gram paper sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 5 - 10 pm for the metallic conductive pattern and 25 - 35 pm for the carbon conductive pattern. Its gap (1116 on Fig. 2A) was 200 - 250 pm wide. On the substrate, the ratio (AM / AC) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.180. Before the IC attachment, the substrate having the antenna printed thereon was compressed using the MSK-HRP- 1A compression machine supplied from MTI Corporation to achieve a smooth surface. In such compression, a gap of 200 - 300 pm was set between the rollers. Afterwards, the IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 5.0 - 6.0 m.

[0161] Experiment 10. The antenna was in accordance with Exemplary Embodiment 7 (Fig. 8) which comprised a metallic conductive pattern and a carbon conductive pattern, screen -printed on the substrate which was a plain PET sheet. The carbon conductive material was W-carbon ink. The resulting antenna had the overall dimensions of 100 x 20 millimeters and the overall thickness of 5 - 10 pm for the metallic conductive pattern and 10 - 15 pm for the carbon conductive pattern. Its gap (1116 on Fig. 8) was 200 - 250 pm wide. On the substrate, the ratio (AM / Ac) of the surface area covered by the metallic conductive pattern (AM) to the surface area covered by the carbon conductive pattern (Ac) was 0.230. The IC was attached in order to close and bridge the gap, thereby completing the conductive circuit and forming an exemplary RF-readable article. The article exhibited a reading range of 7.0 - 8.5 m.

[0162] Table 1 in the next sheet summarizes the foregoing Experiments in their key parameters and performance test results. Further discussion on the results will follow Table 1. Percentage values in the rightmost column, whose heading is labeled as “Relative Improvement in Reading Range (%)”, were calculated with reference to the reading range resulting from Experiment No. I.

[0163]

[0164] Existing commercial RF-readable articles whose antennas are made essentially of metal conductive materials have a minimum reading range of 3.0 meters [2005 IEEE Antennas and Propagation Society International Symposium, Washington, DC, USA, 2005, pp. 353-356 vol. 2B; IEEE Systems Journal, vol. 1, no. 2, pp. 168-176, Dec. 2007. Against this reference, prior art antennas constructed essentially of carbon conductive materials (represented by Comparative Examples I, II and Experiment Nos. I, II) performed undesirably and thus lacked commercial viability. Prior art “hybrid” antennas constructed of carbon and metallic conductive materials (represented by Comparative Example III and Experiment No. Ill) would be barely satisfactory. On the other hand, embodiments according to the present invention overcame the prior-art limitations remarkably, as represented by Experiment Nos. 1 - 10.

[0165] In addition to the synergistic effects arising from the designs of metallic conductive pattern and carbon conductive pattern, the present inventors found that optimization of the AM / Ac ratio improved both the reading range and the production cost, the latter of which being highly dependent on the amount of metallic conductive material consumed in production. Consumption of metallic conductive material is also related to environmental concerns. Accordingly, the present inventors found that the AM / AC ratio of 0.005 - 0.500 was a preferred range, 0.005 - 0.375 was the more preferred range, and 0.010 - 0.200 was the most preferred range. Most of the Experiments using Exemplary Embodiments as shown in Table 1 were directed to the said most preferred range, except Experiment No. 10.

[0166] Another notable factor was the sheet resistivity of the carbon conductive materials: The present inventors found that the RF-readable article’s reading performance improved when the difference between the sheet resistivity of the carbon conductive material (e.g., carbon ink) and that of the metallic conductive material (e.g., silver ink) became smaller. Particularly, the present inventors determined that the sheet resistivity of the carbon conductive material was preferably lower than 20 Q / sq, or more preferably lower than 10 Q / sq, as exemplified in the Experiments’ S- carbon ink and in the W-carbon ink, respectively.

[0167] The RF-readable articles resulting from the Experiments were of the “passive” class. Their reading performances were tested under the UHF band. They may be comprised readily in existing radio frequency identification (RFID) systems and methods without needing to significantly modify the systems or methods. Examples of such existing systems and methods to which an embodiment is applicable may be found in J. Mater. Chem. C, 2023, 11, 406-425, whose contents are incorporated herein by reference.

[0168] SIMULATED EXPERIMENTS

[0169] Furthermore, CST Studio Suite™ simulation software was used to investigate the RF- readable article’s reading performance when the antenna’s metallic conductive pattern is formed of a metallic conductive material that is a copper ink. The simulations were based upon theorems and calculation methods as available in IEEE Transactions on Antennas and Propagation, vol. 53, no. 12, pp. 3870-3876, Dec. 2005, and M S Yeoman & M A O’ Neil, COMSOL Conference 2014

[0170] (Europe, Cambridge), whose contents are incorporated herein by reference

[0171] The relationship between relevant parameters and the reading range was represented by Friis transmission equation, shown in the following expression (1):

[0172] — (1) where r is the reading range; z is the wavelength; Pris the power transmitted by the reader;

[0173] Gris the reader antenna gain; Gais the gain of the receiving tag antenna; r is the power transmission coefficient; and Pth is the minimum threshold power.

[0174] In the simulations, the electrical conductivities of the copper ink and carbon ink were 5.8 x 107S / m and 7,500 S / m, respectively.

[0175] Further, the relative improvements in the reading range were calculated according to the following expression (2): where Gais the gain of the receiving tag antenna; and r is the power transmission coefficient, with re / connoting the reference antenna and x connoting the antenna presently compared against the reference antenna.

[0176] Table 2 below summarizes the above-described Simulations in their key parameters and simulated performances. For avoidance of doubt, all metallic conductive patterns were simulated based on the copper ink when printed and dried upon the substrate; and the reference antenna for the Relative Improvements in Reading Range (%) was Simulation I, whose antenna design was in accordance with Comparative Example IV (Fig. ID).

[0177] Table 2 above further demonstrates that an RF-readable article bearing an antenna according to an exemplary embodiment (represented by Simulation Nos. 1 - 6) when that antenna comprised a metallic conductive pattern that was formed of a copper ink would, similarly to the above- mentioned Experiments involving silver inks, exhibit a remarkable performance improvement over a conventional “hybrid” carbon-metallic antenna (represented by Simulation No. I).

[0178] Fist of References 10 Substrate

[0179] 20 Integrated circuit

[0180] 100 Antenna (Comparative Example)

[0181] 110 Metallic conductive pattern

[0182] 114 Metallic band 115 Flat end

[0183] 116 Gap

[0184] 118 IC attachment marker

[0185] 120 Carbon conductive pattern 122 Aperture

[0186] 124 Carbon periphery

[0187] 126 Gap

[0188] 127 Step-tapered end

[0189] 128 IC attachment slot

[0190] 1000 Antenna (Exemplary Embodiment)

[0191] 1100 Metallic conductive pattern

[0192] 1110 Metallic loop

[0193] 1112 First aperture

[0194] 1114 Metallic periphery

[0195] 1114A Inner edge

[0196] 1114B Outer edge

[0197] 1115 Bent end

[0198] 1116 Gap

[0199] 1117 Step-tapered end

[0200] 1118 IC attachment marker

[0201] 1119 Flat end

[0202] 1120 Metallic fin

[0203] 1200 Carbon conductive pattern

[0204] 1212 Second aperture

[0205] 1212A Connective second aperture

[0206] 1214 Inter-aperture lane

[0207] 1216 IC attachment slot

Claims

CLAIMS1. A substrate bearing an antenna for an article that is electronically readable responsively to radio frequency (RF) signals, said antenna comprising a metallic conductive pattern and a carbon conductive pattern, wherein — the metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery, said metallic periphery having a gap that effectively prevents the completion of the metallic loop, and the carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture.

2. The substrate according to claim 1, having the surface area that is covered substantially more by the carbon conductive pattern than by the metallic conductive pattern.

3. The substrate according to claim 2, wherein the ratio of the area covered by the metallic conductive pattern to the area covered by the carbon conductive pattern is within the range of 0.005 - 0.500.

4. The substrate according to claim 3, wherein the ratio of the area covered by the metallic conductive pattern to the area covered by the carbon conductive pattern is within the range of 0.005 - 0.375.

5. The substrate according to claim 3, wherein the ratio of the area covered by the metallic conductive pattern to the area covered by the carbon conductive pattern is within the range of0.01 - 0.20.

6. The substrate according to claim 1 , wherein the metallic conductive pattern is formed of a silver printing ink or a copper printing ink or a mixture thereof, and the carbon conductive pattern is formed of a carbon printing ink having a sheet resistivity of below 20 Q / sq.

7. The substrate according to claim 6, wherein the carbon printing ink has a sheet resistivity of not exceeding 10 Q / sq.

8. The substrate according to claim 1, wherein the metallic conductive pattern has a thickness within the range of 5 - 15 pm or 5 - 11 pm.

9. The substrate according to claim 1 or 8, wherein the carbon conductive pattern has a thickness within the range of 10 - 100 pm or 10 - 80 pm.

10. The substrate according to claim 1, wherein the metallic conductive pattern further comprises a marker configured to locate the attachment of an integrated circuit.

11. An article that is electronically readable responsively to radio frequency (RF) signals, said article comprising a substrate bearing an antenna and an integrated circuit (IC), the said antenna comprising a metallic conductive pattern and a carbon conductive pattern, wherein — the metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery having a gap, the integrated circuit being attached to the metallic periphery to close the gap, thereby effectively completing the metallic loop, the carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture, and the integrated circuit is free of contact with the carbon conductive pattern.

12. The article according to claim 11, wherein substrate’s surface area is covered substantially more by the carbon conductive pattern than by the metallic conductive pattern.

13. The article according to claim 12, wherein the ratio of the surface area covered by the metallic conductive pattern to the surface area covered by the carbon conductive pattern is within the range of 0.005 - 0.500.

14. The article according to claim 13, wherein the ratio of the surface area covered by the metallic conductive pattern to the surface area covered by the carbon conductive pattern is within the range of 0.005 - 0.375.

15. The article according to claim 13, wherein the ratio of the surface area covered by the metallic conductive pattern to the surface area covered by the carbon conductive pattern is within the range of 0.01 - 0.20.

16. The article according to claim 11 , wherein the carbon conductive pattern substantially overlays the metallic conductive pattern except where the integrated circuit is attached thereto.

17. The article according to claim 11, wherein the carbon conductive pattern substantially overlays the metallic periphery except where the integrated circuit is attached thereto.

18. The article according to claim 11, wherein the metallic conductive pattern is formed of a silver printing ink or a copper printing ink or a mixture thereof, and the carbon conductive pattern is formed of a carbon printing ink having a sheet resistivity of below 20 Q / sq.

19. The article according to claim 18, wherein the carbon printing ink has a sheet resistivity of not exceeding 10 Q / sq.

20. The article according to claim 11 , wherein the metallic conductive pattern has a thickness within the range of 5 - 15 pm or 5 - 11 pm.

21. The article according to claim 11 or 20, wherein the carbon conductive pattern has a thickness within the range of 10 - 100 pm or 10 - 80 pm.

22. The article according to claim 11 , wherein the metallic conductive pattern further comprises a marker configured to locate the attachment of the integrated circuit.

23. A radio frequency identification system comprising the article according to any one of claims 11 - 22.

24. A radio frequency identification method comprising electronically reading the article according to any one of claims 11 - 22.

25. A process for preparing, on a substrate, an antenna for an article that is electronically readable responsively to radio frequency (RF) signals, said process comprising a step of causing the substrate to bear a metallic conductive pattern and a carbon conductive pattern, wherein — the metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery, said metallic periphery having a gap that effectively prevents the completion of the metallic loop, and the carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture.

26. The process according to claim 25, wherein the antenna is prepared so that the substrate’s surface area is covered substantially more by the carbon conductive pattern than by the metallic conductive pattern.

27. The process according to claim 26, wherein the ratio of the surface area covered by the metallic conductive pattern to the surface area covered by the carbon conductive pattern is within the range of 0.005 - 0.500.

28. The process according to claim 26, wherein the ratio of the surface area covered by the metallic conductive pattern to the surface area covered by the carbon conductive pattern is within the range of 0.005 - 0.375.

29. The process according to claim 26, wherein the ratio of the surface area covered by the metallic conductive pattern to the surface area covered by the carbon conductive pattern is within the range of 0.01 - 0.

20.

30. The process according to claim 25, wherein the metallic conductive pattern has a thickness within the range of 5 - 15 pm or 5 - 11 pm.

31. The process according to claim 25 or 30, wherein the carbon conductive pattern has a thickness within the range of 10 - 100 pm or 10 - 80 pm.

32. The process according to claim 26, wherein the metallic conductive pattern further comprises a marker configured to locate the attachment of an integrated circuit.

33. A process for producing an article that is electronically readable responsively to radio frequency (RF) signals, said process comprising a step of attaching an integrated circuit (IC) to a metallic conductive pattern on a substrate, said substrate bearing the said metallic conductive pattern and a carbon conductive pattern, wherein —the metallic conductive pattern comprises a metallic loop featuring a first aperture substantially enclosed by a metallic periphery, said metallic periphery having a gap that effectively prevents the completion of the metallic loop, and the carbon conductive pattern features one or a plurality of second apertures, at least one of said second apertures coinciding substantially with the first aperture.

34. The process according to claim 33, wherein the integrated circuit is attached to the metallic periphery to close the gap, thereby effectively completing the metallic loop.

35. The process according to claim 34, wherein the attachment of the integrated circuit is carried out so that the integrated circuit is free of contact with the carbon conductive pattern.

36. The process according to claim 33, wherein the metallic conductive pattern has a thickness within the range of 5 - 15 pm or 5 - 11 pm.

37. The process according to claim 33 or 36, wherein the carbon conductive pattern has a thickness within the range of 10 - 100 pm or 10 - 80 pm.

38. The process according to any one of claim 33 - 35, wherein the metallic conductive pattern further comprises a marker configured to locate the attachment of the integrated circuit.

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