JP7639435B2 - RFID tags - Google Patents

Description

The present invention relates to RF tags that are attached to various metallic objects and objects, such as building materials and parts, battery covers, and food and beverage containers, and in particular to RF tags that are made up of a general-purpose inlay consisting of an IC chip and an antenna.

In general, so-called RF tags, which have built-in IC chips that can read and write specific information about any item or object, are widely used for any item or object. RF tags are also called RFID (Radio Frequency Identification) tags, IC tags, non-contact tags, etc., and are ultra-small communication terminals in the form of tags (shipping tags) formed from so-called inlays (inlets) in which electronic circuits equipped with IC chips and wireless antennas are sealed and coated with a base material such as a resin film, and a reading/writing device (reader/writer) can wirelessly read and write specific information to the IC chip in the tag, or read and write (read-only, write-once, read/write).

By writing specified information onto such an RF tag and attaching it to any item, object, etc., the information recorded on the RF tag can be picked up by a reader/writer, and the information recorded on the tag can be recognized, output, displayed, updated, etc. as specified information relating to the item.
Such RF tags can store hundreds to several kilobits of data in the memory of their IC chip, allowing them to store a sufficient amount of information relating to items, etc. In addition, because communication with the reading/writing device can be performed without contact, there is no need to worry about wear, scratches, or dirt on the contacts. Furthermore, because the tag itself can be poweredless, it can be processed to suit the object and made smaller and thinner.

By using such RF tags, it is possible to record a variety of information about the item to which the tag is attached, such as the name of the item, identification symbol, contents, ingredients, manager, user, usage state, and usage situation.By simply attaching the small, thin tag to the item, it is possible to accurately read and write a wide variety of information that was not possible using characters or barcodes printed on the surface of a label.
The most widely used RF tags are general-purpose inlays (inlets), which are simply IC chips and antennas coated with a film. This type of inlay is small and thin, can be easily attached to any object without taking up much space, and can be used immediately as an RF tag, so it has become widespread in recent years.

However, when such RF tags are attached to metallic objects or objects, the RF tags can be affected by the electrical conductivity of the metal, which can cause problems such as malfunctions or impaired wireless communication with the reader/writer.

Therefore, in the case of attaching an RF tag to a metal object, there have been proposals to change the configuration of the RF tag to one specifically designed for use with metal, in order to avoid the influence of metal (see Patent Documents 1 to 3).
For example, Patent Document 1 proposes a technology that aims to reduce or avoid the effects of metal manhole covers by inserting and placing an electrical conductor into a through hole provided in the metal manhole cover, thereby providing an antenna component with a total length of λ/2 of a specific communication wavelength.

Furthermore, Patent Document 2 proposes a technology in which a first antenna group and a second antenna group, each of which has two linearly polarized antenna elements arranged in parallel with the same polarization direction, are arranged perpendicular to each other in an antenna device used in roadside units for road-to-vehicle communication such as electronic toll collection (ETC) on expressways, thereby ensuring communication even when the vehicle is moving.
Furthermore, Patent Document 3 proposes a technology that uses a small S-shaped dipole antenna as an antenna for electronic tags, thereby achieving good frequency characteristics across the entire UHF band used in RFID systems with a size equivalent to or smaller than that of a half-wavelength dipole antenna.

JP 2018-067165 A JP 2007-020217 A JP 2007-221735 A

However, the technologies proposed in Patent Documents 1 to 3 are all limited to specific objects, such as manholes and ETC systems, and the configurations of the antennas and RF tags themselves are complex and large, making it difficult to reduce the size and cost of the devices.
Furthermore, since RF tags specialized for such specific objects require a complex configuration and structure that is completely different from previous RF tags (inlays), general-purpose inlays cannot be used as is; dedicated tags and antenna structures, etc. must be prepared, which poses problems in terms of versatility and scalability.

Such complex, dedicated tag structures not only increase production costs, but also make the entire tag larger and heavier, thereby undermining the greatest advantages of RF tags, which are that they are small, thin, lightweight, and easy to handle.
RF tags can take advantage of their characteristics of being able to be used as a low-cost, small, lightweight, and large-capacity wireless communication means by utilizing inexpensive, mass-produced general-purpose tags (inlays). However, there was a risk that the benefits and characteristics of RF tags would be reduced if a dedicated tag (inlay) structure required a complex configuration.

On the other hand, in the case of relatively small items such as metal rod-shaped components, battery cases, building materials, food containers, and beverage containers, the locations where RF tags can be attached are limited, and there are also restrictions on the area and shape of the attachment parts, so even if a general-purpose inlay is attached, the required communication characteristics and communication distance may not be obtained.
As such, RF tags are required to be small, lightweight, and versatile, while also meeting the necessary communication distance and characteristics. However, no RF tags have been proposed to date that can simultaneously achieve these two objectives and are particularly effective for small metal objects.

The present invention has been proposed to solve the problems associated with the conventional technology described above, and aims to provide an RF tag that does not require a complex configuration or structure, can use a general-purpose inlay as is, can ensure the required communication distance, and achieves reliable wireless communication, and can be attached to small metal articles that have significant restrictions on the area and shape of the attachment location of the RF tag.

In order to achieve the above-mentioned object, the RF tag of the present invention is an RF tag comprising an inlay having an IC chip and an antenna, an auxiliary antenna electrically connected to the inlay by capacitor coupling, and a support on which the inlay and the auxiliary antenna are stacked, wherein the auxiliary antenna has a shape that follows the outer shape of the mounting surface of an article to which the RF tag is attached, the inlay is arranged overlapping the auxiliary antenna in the outer inner region of the mounting surface, the auxiliary antenna constitutes a slit antenna having a sheet-like conductive member that spreads in a planar manner in the outer inner region of the mounting surface and a slit that penetrates the conductive member in a predetermined shape, and the inlay is arranged so as to overlap at least a portion of the slit .

The present invention also relates to an article to which an RF tag is attached, the article comprising an inlay having an IC chip and an antenna, an auxiliary antenna electrically connected to the inlay, and a support on which the inlay and the auxiliary antenna are stacked, the RF tag being configured as the RF tag according to the present invention described above.

According to the present invention, a general-purpose inlay can be used as is without requiring a complex configuration or structure, and the necessary communication distance can be secured to achieve reliable wireless communication.
This makes it possible to provide RF tags that can be attached to small metal objects, such as metal rod-shaped members, battery cases, building materials, food containers, and beverage containers, which have significant restrictions on the area and shape of the RF tag attachment location.

1 is an oblique view showing a first RF tag according to one embodiment of the present invention, in which (a) shows the RF tag attached to an article to which it is to be attached, and (b) shows the RF tag disassembled into its individual parts. 1 is an oblique view showing a second RF tag according to one embodiment of the present invention, in which (a) shows the RF tag attached to an article to which it is to be attached, and (b) shows the RF tag with each part disassembled. 2A to 2F are plan views each showing a schematic example of an arrangement of an inlay and an auxiliary antenna constituting the first RF tag shown in FIG. 1. 1A to 1B are plan views each showing a schematic example of the arrangement of an inlay and an auxiliary antenna that constitute the first RF tag shown in FIG. 1, and FIG. 1C to 1D are front views each showing a schematic example of the stacked configuration of the first RF tag. 3A to 3F are plan views each showing a schematic example of an arrangement of an inlay and an auxiliary antenna constituting the second RF tag shown in FIG. 2. 3A to 3C are plan views each showing a schematic example of an arrangement of an inlay and an auxiliary antenna constituting the second RF tag shown in FIG. 2. 3A to 3B are plan views each showing a schematic configuration example of the inlay and auxiliary antenna that constitute the second RF tag shown in FIG. 2, and FIG. 3C is a front view showing a schematic configuration example of the stacked configuration of the second RF tag. 1A to 1E are front views each showing a schematic example of a stacked configuration of a first or second RF tag and a target article. 3 is an explanatory diagram showing a production example of the second RF tag shown in Figure 2, where (a) is a plan view of the inlay, (b) is a plan view of the auxiliary antenna, (c) is a plan view of the substrate, (d) is a plan view of the inlay, auxiliary antenna, and substrate aligned, and (e) is a front view showing a schematic stacking structure of each part of the RF tag. 4 is a line graph showing the relationship between frequency and communication distance, illustrating the communication characteristics of the first RF tag shown in FIG. 1 . 3 is a line graph showing the relationship between frequency and communication distance, illustrating the communication characteristics of the second RF tag shown in FIG. 2 .

Hereinafter, an embodiment of an RF tag according to the present invention will be described with reference to the drawings.
FIG. 1 is an oblique view showing a first RF tag 1A according to one embodiment of the present invention, and FIG. 2 is an oblique view showing a second RF tag 1B, where (a) shows the RF tag attached to an article to which it is to be attached, and (b) shows the RF tag with each part disassembled.
As shown in Figures 1 and 2, the RF tag 1 (first RF tag 1A/second RF tag 1B) of this embodiment is configured such that an inlay 10 and a planar auxiliary antenna 20 constituting an RF tag that performs wireless communication are arranged in a stacked state, and the inlay 10 and the auxiliary antenna 20 are mounted on the surface of a substrate 50, and are covered and protected by a surface layer 40 to form the RF tag 1 (1A/1B).

In the RF tag 1 of this embodiment, the auxiliary antenna 20 and the base material 50 have shapes that follow the outline of the mounting surface of the article 100 to which the RF tag 1 is to be attached, and the inlay 10 is positioned overlapping the auxiliary antenna 20 in the inner area of the outline of the mounting surface of the article 100.
Here, the item 100 to which the RF tag 1 of this embodiment is attached is a metal item, such as construction materials or parts, battery covers, food and beverage containers, etc., and the outer shape (shape) of the mounting surface to which the RF tag 1 can be attached, such as the top, bottom, or end faces of the item 100, has various shapes, such as square, rectangle, trapezoid, oval, circle, etc.
Therefore, the outer shape of the RF tag 1 is also formed to correspond to the outer shape of the mounting surface of the article 100 to which it is to be attached, into the same shape (similar shape) as a square, rectangle, trapezoid, oval, circle, etc. (see Figure 3-7).

Furthermore, in this embodiment, two types of RF tags 1 are provided, a first RF tag 1A and a second RF tag 1B, which have auxiliary antennas 20 with different configurations and shapes.
1, the first RF tag 1A has an auxiliary antenna 20 made of a sheet-like conductive material that spreads in a planar shape on the inner side of the outer shape of the attachment surface of the article 100, and a slit 21 that penetrates the conductive material in a predetermined shape constitutes a slit antenna. The inlay 10 is arranged so as to overlap at least a part of the slit 21 of the auxiliary antenna 20.
2, in the second RF tag 1B, the auxiliary antenna 20 constitutes a linear antenna having a plurality of ends that are not short-circuited to each other in the inner region of the outer shape of the attachment surface of the article 100. A part of the inlay 10 is arranged to overlap the auxiliary antenna 20 near the center thereof.

More specifically, as shown in Figures 1 and 2, the RF tag 1 of this embodiment, both the first RF tag 1A and the second RF tag 1B, are configured in almost the same manner except for the shape of the auxiliary antenna 20, and are configured to include an inlay 10 having an IC chip 11 and an antenna 12, a planar auxiliary antenna 20 arranged on the same plane in an insulated state with respect to the inlay 10, a substrate 50 that serves as a support on which the inlay 10 and the auxiliary antenna 20 are arranged and mounted and that functions as a dielectric constant adjustment layer for the mounted inlay 10, and a surface layer 40 that serves as a cover covering the inlay 10 and the auxiliary antenna 20 mounted on the substrate 50.
The first RF tag 1A/second RF tag 1B are each configured so that the auxiliary antenna 20 is formed in a predetermined shape and size that conforms to the outline of the mounting surface of the article 100, and the auxiliary antenna 20 is stacked in a predetermined position relative to the inlay 10 (see Figure 3-7) and mounted on the substrate 50.
Each part of the RF tag 1 (1A/1B) will be described in detail below.

[Inlay]
The inlay 10 constitutes an RF tag from which specific information is read and written wirelessly between a reader/writer (reading/writing device) not shown, and there are various types such as read-only type, write-once type, and read/write type.
Specifically, as shown in Figures 1 and 2, the inlay 10 has an IC chip 11 that stores specified information, and an antenna 12 made of a conductive material that is electrically conductive and connected to the IC chip 11, and the IC chip 11 and antenna 12 are mounted and laminated on the surface of an inlay substrate 13 which is a support body consisting of a single sealing film made of, for example, PET resin.

The IC chip 11 and antenna 12 mounted on the inlay substrate 13 can be sealed and protected by being sandwiched between the sealing films that make up the inlay substrate 13, for example, by a single sealing film folded in half, or by overlapping two sealing films.
In this embodiment, a rectangular inlay 10 is used in which an IC chip 11 and an antenna 12 extending on both sides of the IC chip 11 are sandwiched and sealed by a rectangular inlay substrate 13 .

The IC chip 11 is made up of a semiconductor chip such as a memory, and is capable of recording data of, for example, several hundred bits to several kilobits.
A loop circuit 11a is formed on the IC chip 11 by connecting a loop-shaped circuit conductor around the periphery of the chip, and antennas 12 are connected to both the left and right sides of the IC chip 11 via this loop circuit 11a.
Reading and writing (data retrieval, registration, deletion, updating, etc.) is performed by wireless communication between the IC chip 11 and a reader/writer (not shown) via the antenna 12, and the data recorded in the IC chip 11 is recognized.
The data recorded on the IC chip 11 can be any data, such as the product's identification code, name, weight, content, manufacturer/seller name, manufacturing location, manufacturing date, expiration date, etc., and the data can also be rewritten.

The antenna 12 is formed by forming a thin metal film, such as a conductive ink or a conductive aluminum vapor deposition film, into a predetermined shape and size (length, area) by etching or other processing on the surface of a sheet of sealing film, which serves as the inlay base material 13.
The sealing film constituting the inlay substrate 13 is made of a flexible film material such as polyethylene, polyethylene terephthalate (PET), polypropylene, polyimide, polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS), etc., and it is preferable that the sealing film be made of a transparent PET resin or the like that allows the arranged IC chip 11 and antenna 12 to be visible from the outside.
In addition, the film surface on one side of the inlay substrate 13 may be provided with an adhesive layer or bonding layer so that it can be attached to a substrate or an article.

The communication frequency band used by the inlay 10 may be, for example, the 860 MHz to 960 MHz band, which belongs to the so-called UHF band.
Generally, there are several frequency bands used by RF tags, such as the band below 135 kHz, the 13.56 MHz band, the 860 MHz to 960 MHz band belonging to the UHF band, the 2.45 GHz band, etc. The communication distance over which wireless communication is possible differs depending on the frequency band used, and the optimal antenna length and wiring pattern also differ depending on the frequency band.

In this embodiment, by providing an auxiliary antenna 20 of a specified structure that maintains and improves the communication characteristics of the inlay 10, it is possible to target the UHF band, which has a short wavelength and allows the antenna to be made smaller, for example, the 860 MHz band or the 920 MHz band, and it is possible to obtain good communication characteristics in these frequency bands.
However, provided there are no restrictions on the size of the inlay 10 or the auxiliary antenna 20, the technical concept of the present invention itself is not limited to a specific frequency band, and can of course be applied to any frequency band other than the UHF band, for example.

Here, it is desirable that the size (length) of the inlay 10 be set and formed so as to obtain good communication characteristics by the antenna 12 .
On the other hand, if only the communication characteristics are taken into consideration, the overall length of the antenna 12 and the RF tag 1 would be too long (too large), which is not desirable given the nature of RF tags, which require miniaturization.
Generally, the antenna 12 provided in the inlay 10 is composed of a dipole antenna or the like made of a conductor extending in a straight line or meandering shape on both sides (left and right) of the IC chip 11, and the conductor constituting the antenna 12 extends symmetrically on both sides of the IC chip 11 so that the length is, for example, 1/2 the wavelength of the communication frequency of the IC chip 11.

For this reason, if a general-purpose inlay is used as is, a space is required to place and store at least the length of the antenna 12, so the overall dimensions (length) of the RF tag 1 including the inlay 10 must be greater than the length of the antenna 12 (e.g., 1/2 wavelength), which becomes a factor that hinders miniaturization of the RF tag and design freedom, etc.
In particular, the RF tag 1 of this embodiment is intended to be compatible with items 100 such as metal rod-shaped members, battery cases, building materials, food containers, beverage containers, etc., where the locations to which the RF tag 1 can be attached are limited and there are also restrictions on the area and shape of the attachment portion, and there are cases where it is difficult or impossible to attach a general-purpose inlay as is.

Therefore, in this embodiment, the longitudinal length of the inlay 10 is adjusted and set so that the inlay 10 fits within the inner area of the outer shape of the attachment surface of the article 100.
Specifically, as shown in Figures 1 and 2, by shortening both ends of a general-purpose inlay by evenly cutting (cutting off) or the like, the inlay 10 can be made to a length that does not protrude from the inner outer region of the attachment surface of the item 100 (see Figures 3-7).
In addition, by configuring the antenna 12 of the inlay 10 as a monopole antenna extending only on one side of the IC chip 11 (see Figure 9), the length can be shortened to about half that of a normal inlay, so that the inlay 10 does not protrude from the inner outer region of the mounting surface of the article 100.

In this way, by shortening the overall length of the inlay 10, the overall length of the RF tag 1 can be made smaller (shorter) than the outer inner area of the attachment surface of the item 100 to be attached, making it possible to make the RF tag 1 compatible with small items that have limited attachment surfaces.
The specific arrangement and layering configuration of the inlay 10 (and auxiliary antenna 20) and the outer inner region of the mounting surface of the article 100 will be described further below with reference to FIGS. 3-7.

[Auxiliary antenna]
The auxiliary antenna 20 is intended to improve and adjust the communication characteristics of the above-mentioned inlay 10, and as shown in Figures 1 and 2, is made of a planar conductive member mounted on a substrate 50 and arranged on the same plane as the inlay 10, and is insulated from the inlay 10 which is resin-sealed by the inlay substrate (sealing film) 13.
That is, as described above, the inlay 10 is entirely resin-sealed by the inlay base material 13, and is physically insulated from the auxiliary antenna 20 made of a conductive material.

By stacking and positioning such an auxiliary antenna 20 near the inlay 10, the auxiliary antenna 20 and the IC chip 11 of the inlay 10 are positioned opposite each other via the inlay base material 13, and an electrical connection is made by so-called capacitor coupling.
As a result, by placing the auxiliary antenna 20 opposite the inlay 10 on the same plane, a two-dimensional antenna is formed by the antenna 12 of the inlay 10 and the auxiliary antenna 20, and the auxiliary antenna 20 functions as a booster for the communication radio waves, thereby adjusting and improving the communication characteristics of the inlay 10.

The auxiliary antenna 20 can be formed into a predetermined shape and size (length, area) by, for example, punching an aluminum sheet, printing a conductive ink on the surface of a base film such as PET resin, or etching a thin metal film such as an aluminum vapor deposition film having conductivity formed on the surface of the film.
In this embodiment, the auxiliary antenna 20 is formed in a shape (the same shape, similar shape, etc.) that conforms to the outer contour of the mounting surface of the item 100 to which the RF tag 1 is attached, and the inlay 10 that is placed on top of the auxiliary antenna 20 is designed not to protrude from the inner area of the outer contour of the mounting surface of the item 100.
The specific configuration and shape of such an auxiliary antenna 20, including the arrangement and lamination configuration of the inlay 10, will be described later with reference to Figures 3-7.

[Base material/surface layer]
The substrate 50 serves as a support (substrate layer) on which the above-mentioned inlay 10 and auxiliary antenna 20 are mounted, and also functions as a dielectric constant adjustment layer for the mounted inlay 10.
In this embodiment, the inlay 10 is formed into a plate, surface, etc. that is one size larger than the outer shape of the auxiliary antenna 20 on which it is stacked, so that the inlay 10 and the auxiliary antenna 20 can be arranged and mounted on the same plane without protruding.
The base material 50 that serves as the support for the auxiliary antenna 20 is formed, like the auxiliary antenna 20, into a shape (the same shape, similar shape, etc.) that conforms to the outline of the mounting surface of the item 100 to which the RF tag 1 is attached.

The auxiliary antenna 20 and the inlay 10 are arranged in parallel on the same plane on one surface side (the upper surface side in Figs. 1 and 2) of the substrate 50. The one surface (upper surface) of the substrate 50 on which the inlay 10 and auxiliary antenna 20 are mounted is covered and coated with the surface layer 40 which serves as a cover member. As a result, the inlay 10 and the auxiliary antenna 20 are sealed in a parallel arrangement sandwiched between the substrate 50 and the surface layer 40, and are protected from the outside.
The surface layer 40 is a sheet-like member that is attached or adhered to one side of the base material 50 on which the inlay 10 and the auxiliary antenna 20 are mounted, and can be formed, for example, from a flexible sheet material or film material made of paper, synthetic paper, polyethylene, polyethylene terephthalate (PET), polypropylene, polyimide, or other resin.

On the other hand, the other surface side of the base material 50 (the underside side in Figures 1 and 2), although not specifically shown, can be provided with an adhesive material such as a double-sided tape (adhesive tape) or a plate-shaped magnet, and the adhesive force of the adhesive material or the magnetic force of the magnet allows the base material 50 to be attached to the surface of the metal article 100 to be attached (see adhesive layer 60 shown in Figure 9).
In this manner, at least a portion of the RF tag 1 can be removably attached to the item 100 .
This allows the RF tag 1 to be placed and fixed to the surface of a metal article so that the base material 50 is attached and fixed to the surface of the object to be attached, and the RF tag 1 will not easily fall off or peel off.
In addition, the surface layer 40 may be provided on both sides of the inlay 10 and the auxiliary antenna 20 before they are placed on the base material 50 (see the two surface layers 40 shown in FIG. 9). In this way, the inlay 10 and the auxiliary antenna 20 without the base material 50 can be configured and handled as an RF tag 1.

Here, the base material 50 as described above can be formed from, for example, an acrylic foam or a crosslinked polyolefin foam such as a polyethylene foam or a polypropylene foam.
In addition, the substrate 50 can be constructed from a single strip-shaped member formed from the above-mentioned acrylic foam or cross-linked polyolefin foam, or a single substrate 50 can be constructed by stacking multiple (e.g., two-layer) strip-shaped members.
Furthermore, the magnet for attachment to the above-mentioned metallic article 100 can be configured as a part of the substrate 50. The magnet that becomes the substrate 50 can be configured by forming a magnet that can be attached/mounted by magnetic force to the metal to which the RF tag 1 is to be attached into a plate or strip shape having a predetermined size and thickness corresponding to the substrate 50, and laminating and attaching it to the substrate 50 made of resin or the like.

Furthermore, the above-mentioned substrate 50 can be formed to have a predetermined relative dielectric constant that adjusts the communication characteristics of the inlay 10 arranged together with the auxiliary antenna 20, and can function as a dielectric constant adjustment layer for the inlay 10 mounted or laminated on the substrate 50.
For example, the substrate 50 can be formed of a predetermined material with a predetermined thickness, thereby forming a dielectric constant adjustment layer having a relative dielectric constant suitable for the communication characteristics of the inlay 10.
In this way, by having the substrate 50 have a predetermined dielectric constant and thickness, the substrate 50 can avoid or absorb the effects of the metal to which the RF tag 1 is attached, and the communication characteristics of the RF tag 1 can achieve a good communication distance, as described below.
Therefore, by selecting an appropriate material and thickness for the base material 50, taking into consideration various conditions such as the type of inlay 10 used, its communication characteristics, the item in which the RF tag 1 is used, the usage environment, and the frequency band used, and then selecting and replacing only the base material 50, it becomes possible to use the RF tag 1 for different items or to make it compatible with different communication frequencies.

[RF tag layout and stacking configuration]
Next, the arrangement and stacking structure of each part (inlay 10, auxiliary antenna 20, surface layer 40, and substrate 50) that constitutes the RF tag 1 of this embodiment will be described with reference to FIGS.
As described above, the RF tag 1 of this embodiment has a shape that conforms to the outer contour of the mounting surface of the item 100 to which it is attached, and the inlay 10 is shortened so that it does not protrude beyond the inner area of the outer contour of the mounting surface of the item 100.
For such a shortened inlay 10, the auxiliary antenna 20 functions as a booster for the communication radio waves, enabling the inlay 10 to obtain the desired communication characteristics and communication distance.

Here, it is preferable that the auxiliary antenna 20 is formed so that the overall antenna length is an integer multiple or an integer fraction of the wavelength of the radio frequency of the inlay 10, for example, approximately 1/2 the wavelength of the radio frequency.
According to the principle of patch antennas, the length of the long side (longitudinal direction) of the auxiliary antenna 20 can be matched by making it an integer multiple or an integer fraction (1/2, 1/4, 1/8, . . . ) of the wavelength of the communication radio wave.

However, if the length of the auxiliary antenna 20 were simply made linear and equal to 1/2 the wavelength, the overall size (length) of the RF tag 1 would be determined by the overall length of the auxiliary antenna 20, and the overall size (length) of the RF tag 1 would also be approximately 1/2 the wavelength or slightly larger (longer), making it difficult or impossible to use for small metal articles and the like that have restrictions on the area and shape of the attachment location of the RF tag 1.
Moreover, it is not preferable for the overall length of the tag to be too long (too large) because of the nature of RF tags, which require miniaturization.

Therefore, in this embodiment, the RF tag 1 is provided with two types of RF tags, a first RF tag 1A and a second RF tag 1B, which have different configurations and shapes of the auxiliary antenna 20, thereby maintaining and improving the communication characteristics of the shortened inlay 10 as described above and achieving the overall miniaturization of the RF tag 1.
Hereinafter, the specific arrangement and stacking configuration of the first RF tag 1A and the second RF tag 1B will be described with reference to the drawings.

[First RF tag]
In the first RF tag 1A, the auxiliary antenna 20 is formed of a sheet-like conductive material that spreads out over the inner peripheral area of the attachment surface of the article 100, and is configured as a slit antenna having a slit 21 formed in a predetermined shape that penetrates the conductive material.
The inlay 10 is arranged in the inner region of the auxiliary antenna 20 so as to overlap at least a portion of the slit 21 .
By constructing the auxiliary antenna 20 as a slit antenna in this manner, even if the total length of the planar auxiliary antenna 20 is, for example, less than approximately half the wavelength of the radio wave frequency of the inlay 10, it is possible to ensure a certain level of communication distance for the inlay 10 due to electromagnetic resonance via the slits 21 (slit antenna effect) (see Figure 10).
This makes it possible to ensure that the auxiliary antenna 20 and the entire RF tag 1 can be attached to the attachment surface of the article 100 which has constraints such as area and shape, while still ensuring good communication characteristics of the RF tag 1.

3(a) to (f) and 4(a) to (b) are plan views each showing a schematic planar shape of the auxiliary antenna 20 of the first RF tag 1A constituted by a slit antenna and the positional relationship of the inlay 10.
In the example shown in Figure 3 (a), the auxiliary antenna 20 (and the substrate 50) has an approximately square outer shape that matches the outer shape of the mounting surface of the item 100, a linear slit 21 is formed approximately at the center of the auxiliary antenna 20, and the inlay 10 is positioned in a horizontal direction (left to right in the figure) that intersects (orthogonal to) the slit 21 so that the IC chip 11 overlaps the center of the slit 21.
In the example shown in Figure 3 (b), instead of the straight slit 21 shown in Figure 3 (a), a slit 21 is formed in a U-shape (inverted U-shape) when viewed in a plane, and the inlay 10 is positioned horizontally (left to right in the figure) at approximately the center of the auxiliary antenna 20 so as to overlap this slit 21.

In the example shown in Figure 3 (c), the auxiliary antenna 20 (and the substrate 50) has an approximately elliptical outer shape that matches the outer shape of the mounting surface of the item 100, a linear slit 21 is formed approximately at the center of the auxiliary antenna 20, and the inlay 10 is positioned in a horizontal direction (left to right in the drawing) that intersects (orthogonal to) the slit 21 so that the IC chip 11 overlaps the center of the slit 21.
In the example shown in Figure 3 (d), instead of the straight slit 21 shown in Figure 3 (c), a slit 21 is formed in a U-shape (inverted U-shape) when viewed from above, and the inlay 10 is positioned horizontally (left to right in the figure) at approximately the center of the auxiliary antenna 20 so as to overlap this slit 21.

In the example shown in Figure 3 (e), the auxiliary antenna 20 (and the substrate 50) has an approximately trapezoidal (triangle with a prefix) outer shape that matches the outer shape of the mounting surface of the item 100, a linear slit 21 is formed approximately at the center of the auxiliary antenna 20, and the inlay 10 is positioned in a horizontal direction (left to right in the figure) that intersects (orthogonal to) the slit 21 so that the IC chip 11 overlaps the center of the slit 21.
In the example shown in Figure 3 (f), the auxiliary antenna 20 (and the substrate 50) has an approximately rectangular outer shape that matches the outer shape of the mounting surface of the item 100, and a slit 21 is formed in a C-shape (inverted U-shape) when viewed in a plane, and the inlay 10 is positioned horizontally (left to right in the figure) approximately in the center of the auxiliary antenna 20 so as to overlap this slit 21.

In the example shown in Figure 4 (a), the auxiliary antenna 20 (and the substrate 50) has an almost perfectly circular outer shape that matches the outer shape of the mounting surface of the item 100, a linear slit 21 is formed almost at the center of the auxiliary antenna 20, and the inlay 10 is positioned in a horizontal direction (left to right in the figure) that intersects (orthogonal to) the slit 21 so that the IC chip 11 overlaps the center of the slit 21.
In the example shown in Figure 4(b), instead of the straight slit 21 shown in Figure 4(a), a slit 21 is formed in a U-shape when viewed from above, and the inlay 10 is positioned horizontally (left to right in the figure) at approximately the center of the auxiliary antenna 20 so as to overlap this slit 21.

4(c) to (d) are front views each showing a schematic example of a layered structure of the first RF tag 1A as described above.
As shown in FIG. 4( c ), the first RF tag 1A is arranged so that the base material 50 , the auxiliary antenna 20 , the inlay 10 , and the surface layer 40 are layered in this order without protruding from the outer edge of the attachment surface of the article 100 .
In addition, the first RF tag 1A can also be arranged and configured in a cylindrical shape in which the outer edge of the auxiliary antenna 20 protrudes from the outer edge of the mounting surface of the article 100 and covers the outer edge of the base material 50, as shown in Figure 4 (d).

[Second RF tag]
In the second RF tag 1B, the auxiliary antenna 20 is configured as a linear antenna having a plurality of ends that are not short-circuited to each other in the inner peripheral area of the attachment surface of the article 100.
A part of the inlay 10 is arranged to overlap the auxiliary antenna 20 near the center thereof.
By constructing the auxiliary antenna 20 in this manner as a linear antenna, the overall length of the auxiliary antenna 20 in the inner outer region of the mounting surface of the item 100 can be formed to be, for example, approximately 1/2 the wavelength of the radio frequency of the inlay 10, making it possible to ensure a certain or greater communication distance for the inlay 10 (see Figure 11).
This makes it possible to ensure that the auxiliary antenna 20 and the entire RF tag 1 can be attached to the attachment surface of the article 100 which has constraints such as area and shape, while still ensuring good communication characteristics of the RF tag 1.

In this way, in the second RF tag 1B, the overall length of the auxiliary antenna 20 is set to approximately half the wavelength of the radio frequency of the inlay 10, thereby achieving good communication characteristics.
Specifically, for example, when the communication frequency of the target inlay 10 is 920 MHz, λ≈326.0 mm, and λ/2≈163.0 mm. Therefore, the auxiliary antenna 20 is formed so that the length of the long side is about 163.0 mm.

As described above, the base material 50 on which the inlay 10 and the auxiliary antenna 20 are laminated is made of a dielectric material such as resin, and the apparent wavelength can be shortened due to the wavelength shortening effect of this dielectric material.
For example, when the dielectric constant of the substrate 50 in this embodiment is approximately "2", the wavelength shortening effect is approximately "1.4", and the length of the long side of the auxiliary antenna 20 is half the wavelength divided by "1.4", which is "163/1.4=116 mm".
In this way, the length may vary depending on the material and dielectric constant of the base material 50 of the RF tag 1, the environment in which the tag is used, the manner of use, and other factors that affect communication characteristics.

In this embodiment, the inlay 10 is arranged in a predetermined positional relationship so as to be superimposed on the surface of the auxiliary antenna 20 formed in the shape and dimensions described above.
Figures 5(a) to (f), 6(a) to (c), and 7(a) to (b) are plan views each showing a schematic planar shape of the auxiliary antenna 20 of the second RF tag 1B, which is composed of an antenna having a length approximately half the wavelength of the radio frequency of the inlay 10, and the positional relationship of the inlay 10.

In the example shown in Figure 5 (a), the base material 50 has an approximately square outer shape that matches the outer shape of the mounting surface of the item 100, and the auxiliary antenna 20 is formed in the inner area of the outer shape of the base material 50 as an annular (ring-shaped) linear antenna that follows the outer shape (inner edge) of the base material 50 (item 100), and the inlay 10 is arranged vertically (top to bottom in the drawing) in the center of the base material 50 so that one end of the inlay 10 overlaps with a part of the linear antenna (the central part of the upper edge).
In the example shown in Figure 5 (b), instead of the annular linear antenna shown in Figure 5 (a), a linear antenna that is S-shaped in a planar view and follows the outer shape (inner edge) of the substrate 50 (item 100) is formed, and a part of the inlay 10 (IC chip 11) overlaps with a part of this linear antenna (the central part of the S-shape), so that the inlay 10 is arranged vertically (top and bottom in the drawing) in the center of the substrate 50.

In the example shown in Figure 5 (c), the base material 50 has an approximately elliptical outer shape that matches the outer shape of the mounting surface of the item 100, and the auxiliary antenna 20 is formed in the inner area of the outer shape of the base material 50 as a linear antenna that is S-shaped in a planar view and follows the outer shape (inner edge) of the base material 50 (item 100), and the inlay 10 is arranged vertically (top to bottom in the drawing) in the center of the base material 50 so that a part of the linear antenna (the central part of the S shape) overlaps with a part of the inlay 10 (IC chip 11).
In the example shown in Figure 5 (d), the base material 50 has an approximately rectangular outer shape (inner edge) that matches the outer shape of the mounting surface of the item 100, and the auxiliary antenna 20 is formed in the inner area of the outer shape of the base material 50 as a linear antenna that is S-shaped in a planar view and follows the outer shape of the base material 50 (item 100), and a part of the linear antenna (the central part of the S-shape) overlaps with a part of the inlay 10 (IC chip 11), so that the inlay 10 is arranged vertically (top to bottom in the drawing) in the center of the base material 50.

In the example shown in Figure 5 (e), the base material 50 has an outer shape that is approximately trapezoidal (triangle with a prefix) that matches the outer shape of the mounting surface of the item 100, and the auxiliary antenna 20 is formed in the inner area of the outer shape of the base material 50 as a linear antenna that is S-shaped in a planar view and follows the outer shape (inner edge) of the base material 50 (item 100), and the inlay 10 is arranged vertically (top to bottom in the drawing) in the center of the base material 50 so that a part of the linear antenna (the central part of the S shape) overlaps with a part of the inlay 10 (IC chip 11).
In the example shown in Figure 5 (f), the base material 50 has an approximately rectangular outer shape (inner edge) that matches the outer shape of the mounting surface of the item 100, and the auxiliary antenna 20 is formed in the inner area of the outer shape of the base material 50 as a linear antenna that is T-shaped in a planar view and follows the outer shape of the base material 50 (item 100), and is arranged horizontally (left to right in the figure) so that a part of the linear antenna (upper edge of the T) overlaps with a part of the inlay 10 (upper edge in the longitudinal direction).

6(a) to 6(c) show RF tags 1B having a substantially elliptical outer shape similar to that shown in FIG. 5(c), each of which has a different arrangement of the auxiliary antenna 20 and the inlay 10. FIG.
6A is a case in which the IC chip 11 of the inlay 10 is arranged so as to overlap the central portion of the S-shape of the auxiliary antenna 20, similar to the example of FIG. 5C.
The example of FIG. 6( b ) is a case where, in addition to the configuration of FIG. 6( a ), one end of the inlay 10 is arranged to overlap the upper edge portion of the S-shape of the auxiliary antenna 20 .
The example of FIG. 6( c ) is a case where, in addition to the configuration of FIG. 6( a ), the inlay 10 is arranged so that both ends of the inlay 10 overlap the upper and lower edge portions of the S-shape of the auxiliary antenna 20 .

In this way, in the second RF tag 1B, the inlay 10 can be arranged so that at least a portion of the end of the inlay 10 overlaps the auxiliary antenna 20.
In this case, the inlay 10 can be arranged so as to overlap the auxiliary antenna 20 at multiple points (see FIG. 6(c)).
In this way, by varying the arrangement configuration (overlap pattern) of the inlay 10 and the auxiliary antenna 20, it becomes possible to adjust and set up each RF tag 1B (inlay 10) so as to obtain optimal communication characteristics.

In the example shown in Figure 7 (a), the base material 50 has an almost circular outer shape that matches the outer shape of the mounting surface of the item 100, and the auxiliary antenna 20 is formed in the inner area of the outer shape of the base material 50 as a linear antenna that is S-shaped in a planar view and follows the outer shape (inner edge) of the base material 50 (item 100), and the inlay 10 is arranged horizontally (left to right in the figure) in the center of the base material 50 so that a part of the linear antenna (the central part of the S shape) overlaps with a part of the inlay 10 (IC chip 11).
The example shown in Figure 7 (b) is an inlay 10 arranged in the horizontal direction (left and right in the drawing) at the center of the substrate 50 shown in Figure 7 (a) is arranged in the vertical direction (top and bottom in the drawing) at the center of the substrate 50.

In this way, in the second RF tag 1B, the auxiliary antenna 20 has a straight portion (the central portion of the S-shape) that extends in a straight line, and the inlay 10 can be positioned so that the IC chip 11 of the inlay 10 overlaps the straight portion of the auxiliary antenna 20.
In this case, the inlay 10 can be placed on top of the auxiliary antenna 20 so that the polarization axis of the inlay 10 and the straight portion of the auxiliary antenna 20 are parallel to each other or intersect at a predetermined angle.
In this way, by varying the arrangement configuration (overlap pattern) of the inlay 10 and the auxiliary antenna 20, it becomes possible to adjust and set up each RF tag 1B (inlay 10) so as to obtain optimal communication characteristics.

FIG. 7C is a front view showing a schematic example of a layered structure of the second RF tag 1B as described above.
As shown in the figure, the second RF tag 1B is arranged in the order of base material 50, auxiliary antenna 20, inlay 10, and surface layer 40 in a layered manner, without protruding from the outer edge of the attachment surface of the article 100, similar to the first RF tag 1A (see Figure 4 (c)).

[Layer structure of RF tag]
Next, the layered structure of each part (inlay 10, auxiliary antenna 20, surface layer 40, and base material 50) constituting the RF tag 1 of this embodiment, which is common to the first RF tag 1A and second RF tag 1B described above, will be explained with reference to Figure 8.
8(a) to 8(e) are front views each showing a schematic example of a stacked configuration of a (first or second) RF tag 1 and a target article 100. FIG.

First, as shown in FIG. 8(a), the RF tags 1 can be arranged in a stacked manner without protruding from the outer edge of the attachment surface of the article 100 (see also FIG. 4(c) and FIG. 7(c)).
In this way, the RF tag 1 can be attached without protruding from the attachment surface of the article 100, and the RF tag 1 is prevented from getting caught or becoming a hindrance when managing, storing, handling, etc., the article.

Also, as shown in FIG. 8(b), the RF tag 1 can be arranged and configured in a cylindrical or lid-like shape such that its outer edge protrudes beyond the outer edge of the mounting surface of the item 100 and covers the side surface continuing from the outer edge of the item 100 (see also FIG. 4(d)).
In this way, the RF tag 1 can be configured to have an area covering at least a part of the side surface of the article that is continuous with the attachment surface of the article 100. In this case, the area covering the side surface of the article 100 may be, for example, the outer edge of the auxiliary antenna 20 (see FIG. 4(d)), or may be the support body of the RF tag 1 (substrate 50 or surface layer 40).
By configuring the RF tag 1 in this manner as a cylinder/lid shape, the RF tag 1 can be easily attached to the item 100, and the RF tag 1 can be prevented from accidentally becoming detached or falling off the item 100.

As shown in FIG. 8C, the RF tag 1 is arranged such that the base material 50, the auxiliary antenna 20, the inlay 10, and the surface layer 40 are layered in this order on the attachment surface of the article 100.
In this case, at least a portion of the RF tag 1 can be in contact with a metal portion of the article 100 and electrically grounded.
For example, as shown in FIG. 8( d ), by making a part of the inlay 10 protrude or extend beyond the outer shape of the article 100 , it is possible to electromagnetically couple with a metal part of the article 100 .
Also, as shown in FIG. 8( e ), a part of the auxiliary antenna 20 can be projected or extended from the outer shape of the article 100 to be grounded to a metal part of the article 100 .
In this way, the RF tag 1 can be grounded to the metal part of the article 100 to which it is to be attached, thereby making it possible to avoid or reduce the influence of the metal part of the article 100 .

[Example of RF tag production]
Next, specific examples (embodiments) of the RF tag 1 of this embodiment as described above will be described for the first RF tag 1A and the second RF tag 1B.
In this example, a first RF tag 1A or a second RF tag 1B is attached to a metal member (round aluminum bar) on which the RF tag 1 is to be attached, with one end face of the metal member serving as the attachment surface.
In both examples, the metal member to be attached is a circle with an end face that serves as the attachment surface having a diameter of approximately 70 mm and a height of approximately 75 mm, as shown in Figures 9(a) and 9(d), and a first RF tag 1A or a second RF tag 1B is produced that fits within the inner area of the outer shape of this end face.

FIG. 9A is an explanatory diagram showing a specific example of the production of a first RF tag 1A among the RF tags 1 of this embodiment.
As shown in the figure, in this example, the auxiliary antenna 20 (and the base material 50 (made of resin with a thickness of 3 mm)) has an almost perfectly circular outer shape with a diameter of approximately 60 mm to match the outer shape of the mounting surface of the metal member, and a linear slit 21 of approximately 55 mm x 5 mm is formed approximately in the center of the auxiliary antenna 20.
The IC chip 11 is placed so as to overlap the center of the slit 21 of the auxiliary antenna 20. Specifically, in this example, a general-purpose inlay 10 of approximately 40 mm×4 mm is configured to be placed in a direction intersecting (orthogonal to) the slit 21. The auxiliary antenna 20 in which the slit 21 is formed is configured so that a part of it is grounded to a metal member.
FIG. 9(b) shows a schematic diagram of the layered structure of the first RF tag 1A according to this example.
As shown in the figure, the first RF tag 1A is configured such that an adhesive layer 60, a base material 50, an auxiliary antenna 20, an inlay 10, and a surface layer 40 are layered in this order from the upper surface of the mounting surface.

FIG. 9C is an explanatory diagram showing a specific example of the production of the second RF tag 1B among the RF tags 1 of this embodiment.
In the present example shown in the figure, the inlay 10 is a general-purpose inlay with an antenna and has a total length of about 38 mm.
Specifically, as shown in the figure, the auxiliary antenna 20 is configured as a linear antenna having an S-shape in a plan view with a diameter of approximately 45 mm, a width of approximately 3 mm, and an end opening of approximately 10 mm, so that it can be accommodated within the inner area of the upper surface of the mounting surface of the metal member.
The above-mentioned parts are stacked in the inner region of the base material 50 (made of resin with a thickness of 3 mm) with the auxiliary antenna 20, and the inlay 10 is stacked and positioned in the vertical direction (top and bottom in the drawing) so that it overlaps the central part of the S-shape of the auxiliary antenna 20 and intersects with the straight part of the S-shape.
FIG. 9(d) shows a schematic diagram of the layered structure of the second RF tag 1B according to this example.
As shown in the figure, the second RF tag 1B is configured such that an adhesive layer 60, a base material 50, an auxiliary antenna 20, an inlay 10, and a surface layer 40 are layered in this order from the upper surface of the mounting surface.

In addition, in both of the above two examples, as shown in Figures 9(b) and 9(d), an adhesive layer 60 is provided on the bottom surface of the base material 50 that contacts the upper surface of the end mounting surface of the metal member, and the base material 50 is affixed and fixed to the upper surface of the mounting surface to be attached, so that the RF tag 1 does not easily fall off or peel off.

[Communication characteristics]
Next, the communication characteristics of the RF tag 1 according to this embodiment having the above-mentioned configuration will be described with reference to FIGS.
FIG. 10 is a line graph showing the relationship between frequency and communication distance, which indicates the communication characteristics of the first RF tag 1A.
FIG. 11 is a line graph showing the relationship between frequency and communication distance, which indicates the communication characteristics of the second RF tag 1B.

As shown in these graphs, in the RF tag 1 of this embodiment, it is understood that a constant communication distance is obtained at 920 MHz for each of the first RF tag 1A and the second RF tag 1B.
With the first RF tag 1A, as shown in Figure 10, a maximum communication distance of approximately 4.0 m can be achieved in the 920 to 960 MHz band, and with the second RF tag 1B, as shown in Figure 11, a communication distance of 1.5 m or more can be achieved in the 920 to 930 MHz band, which are sufficient results for the communication distance of the RF tag 1 attached to the item 100 (the metal member (round aluminum rod) described in this production example).

As described above, according to the RF tag 1 of this embodiment, the inlay 10 that is configured to conform to the outer shape of the mounting surface of the article 100 to which it is attached and that performs wireless communication is shortened and positioned so as not to protrude beyond the inner area of the outer shape of the mounting surface of the article 100, and further, the auxiliary antenna 20 that is formed in a predetermined shape that conforms to the outer shape of the mounting surface of the article 100 for such a shortened inlay 10 allows the inlay 10 to obtain sufficient communication characteristics and communication distance.

As a result, the RF tag 1 of this embodiment does not require complex configurations or structures, and can use general-purpose inlays as is, while ensuring the necessary communication distance and achieving reliable wireless communication.It is also possible to reduce the length of the antenna 12 of the inlay 10 to less than approximately half the wavelength of the radio frequency used for wireless communication, while maintaining good notification characteristics, and to reduce the overall size of the RF tag 1.
Therefore, it is possible to realize an RF tag that can be attached to small metal objects such as metal rod-shaped members, battery cases, building materials, food containers, and beverage containers, which have significant restrictions on the area and shape of the RF tag attachment location.

As described above, according to the RF tag 1 of this embodiment, it is possible to construct an RF tag 1 that can be used for small metal objects, etc., while using a general-purpose inlay as is, without requiring a specific dedicated structure or configuration as in conventional RF tags. Even if the object to be used, the communication frequency of the RF tag 1, or the usage environment is different, it is possible to respond by simply changing or replacing the configuration, such as the shape and size of the auxiliary antenna 20.
Therefore, according to the RF tag 1 of this embodiment, it is possible to provide an RF tag 1 that can be attached to various small items and objects that have limited attachment locations and constraints on the area and shape of the attachment portion, and it is possible to actively use existing general-purpose inlays, so that the entire tag can be constructed at low cost, and it is possible to realize a highly reliable RF tag that has excellent versatility, expandability, weather resistance, etc., and can provide good communication characteristics at low cost.

The RF tag of the present invention has been described above by showing preferred embodiments. However, it goes without saying that the RF tag of the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.
For example, the RF tag 1 according to the above-described embodiment is configured to be covered by the surface layer 40, but at least a portion of the RF tag may be covered by a film member different from the surface layer, such as a shrink film, etc. Also, at least a portion or the entire RF tag may be covered by a cover member such as a housing or a metal cover.
In this way, the RF tag is protected by the film member or cover member, and the weather resistance, heat resistance, impact resistance, waterproofing, etc. of the RF tag can be improved.

Furthermore, in addition to the inlay that performs wireless communication, the RF tag according to the present invention can also be equipped with other identification means, such as a barcode (one-dimensional code) or two-dimensional code for backup or management of the RF tag. In this way, management information and backup information of the RF tag can be recorded and stored, improving the convenience and safety of the RF tag.

The RF tag of the present invention can also be configured so that, when it is removed from the article to which it is attached, the inlay records predetermined information indicating that at least a portion of the inlay has been destroyed or that the RF tag has been removed. For example, by providing a sensor that breaks when the inlay is peeled off, it is possible to detect and output the removal of the inlay or RF tag. This makes it possible to detect the removal or destruction of the RF tag unintentionally by the user, and makes it possible to prevent or detect the destruction or leakage of information at an early stage, and to improve the safety of the RF tag.

In addition, in the above-described embodiments, metal rod-shaped members, battery cases, building materials, food containers, and beverage containers are used as examples of items in which the RF tag of the present invention can be used, but the items and objects in which the RF tag of the present invention can be used are not limited to these.
In other words, the RF tag of the present invention can be applied to any item or object as long as an RF tag is used and specified information and data are read and written via a reader/writer, and it can of course also be used with items and objects other than those made of metal.

The present invention can be suitably used as an RF tag that can be attached to small objects with limited mounting surface area or shape, such as metal rod-shaped members, battery cases, food cans, and beverage cans.

REFERENCE SIGNS LIST 1 RF tag 10 Inlay 11 IC chip 11a Loop circuit 12 Antenna 13 Inlay substrate 20 Auxiliary antenna 40 Surface layer 50 Substrate

Claims (17)

an inlay having an IC chip and an antenna;
an auxiliary antenna electrically connected to the inlay by capacitive coupling;
An RF tag comprising the inlay and a support on which an auxiliary antenna is stacked,
the auxiliary antenna has a shape that conforms to the outline of the attachment surface of the article to which the RF tag is attached,
The inlay is disposed in an outer periphery inner region of the mounting surface so as to overlap the auxiliary antenna ;
The auxiliary antenna,
A slit antenna is formed having a sheet-like conductive member that spreads in a planar shape on an inner region of the outer shape of the mounting surface, and a slit that penetrates the conductive member in a predetermined shape,
The RF tag is characterized in that the inlay is arranged so as to overlap at least a portion of the slit . The RF tag according to claim 1 , wherein the auxiliary antenna or the support has an area covering at least a part of a side surface of the article that is continuous with the attachment surface. The inlay is disposed across the slit so that the IC chip of the inlay overlaps the slit.
3. The RF tag according to claim 1 or 2 . The RF tag according to any one of claims 1 to 3 , wherein the slit is formed in a U-shape when viewed from above the auxiliary antenna. an inlay having an IC chip and an antenna;
an auxiliary antenna electrically connected to the inlay by capacitive coupling;
An RF tag comprising the inlay and a support on which an auxiliary antenna is stacked,
the auxiliary antenna has a shape that conforms to the outline of the attachment surface of the article to which the RF tag is attached,
The inlay is disposed in an outer periphery inner region of the mounting surface so as to overlap the auxiliary antenna;
The auxiliary antenna,
A linear antenna having a plurality of ends that are not short-circuited to each other is configured in an inner region of the outer shape of the mounting surface,
An RF tag, characterized in that a part of the inlay is arranged so as to overlap with the auxiliary antenna near a central portion of the auxiliary antenna. the auxiliary antenna has a straight portion extending linearly,
The RF tag according to claim 5 , wherein the inlay is arranged so that the IC chip of the inlay overlaps the straight portion. The RF tag according to claim 6 , wherein the inlay is arranged overlapping the auxiliary antenna so that the polarization axis of the inlay and the straight portion are parallel to each other or intersect at a predetermined angle. The RF tag according to any one of claims 5 to 7 , characterized in that the inlay is arranged so that at least a portion of an end of the inlay overlaps the auxiliary antenna. The RF tag according to any one of claims 5 to 8 , characterized in that the inlay is arranged so as to overlap the auxiliary antenna at a plurality of points. The RF tag according to any one of claims 5 to 9 , characterized in that the auxiliary antenna has a length of approximately 1/4 to 1/2 of the wavelength of the radio frequency of the inlay. The RF tag according to any one of claims 5 to 10 , characterized in that the auxiliary antenna is formed in any one of an S-shape, a ring shape, and a T-shape when viewed from above. When at least a portion of the article is metal,
The RF tag according to any one of claims 1 to 11 , characterized in that the inlay or the auxiliary antenna is grounded to a metal part of the article. The RF tag according to any one of claims 1 to 12 , characterized in that at least a portion of the RF tag is covered with a film member or a cover member. The RF tag according to any one of claims 1 to 13 , further comprising other identification means in addition to the inlay. The RF tag according to any one of claims 1 to 14 , characterized in that at least a part of the RF tag is detachably attached to the article. When the RF tag is removed from the item,
The RF tag according to any one of claims 1 to 15 , characterized in that the inlay records predetermined information indicating that at least a portion of the inlay has been destroyed or the RF tag has been removed. An article to which an RF tag is attached, the article comprising: an inlay having an IC chip and an antenna; an auxiliary antenna electrically connected to the inlay; and a support on which the inlay and the auxiliary antenna are stacked,
An article equipped with an RF tag, characterized in that the RF tag is an RF tag according to any one of claims 1 to 16 .

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