JP7314626B2 - RF tag - Google Patents

Description

The present invention relates to an RF tag that can be attached to any article or object such as a metal article and used, and in particular, an RF tag that can protect an inlay equipped with an IC chip from physical and mechanical external forces and impacts.

2. Description of the Related Art In general, a so-called RF tag containing an IC chip that stores predetermined information about an article or object in a readable and writable manner is widely used for any article or object.
An RF tag is also called an RFID (Radio Frequency Identification) tag, an IC tag, a non-contact tag, etc. It is an ultra-compact communication terminal in which an electronic circuit having an IC chip and a wireless antenna is sealed and coated with a base material such as a resin film to form a so-called inlay (inlet) in the shape of a tag (tag). Writing and reading/writing (read-only, write-once, read/write) can be performed.

By writing predetermined information in such an RF tag and attaching it to an arbitrary article, object, etc., the information recorded in the RF tag can be picked up by a reader/writer, and the information recorded in the tag can be recognized, output, displayed, updated, etc. as predetermined information related to the article.
Such RF tags can record several hundred bits to several kilobits of data in the memory of the IC chip, and can record a sufficient amount of information as information about articles, etc., and can communicate with the reading / writing device side without contact, so there is no need to worry about wear, scratches, dirt, etc. on the contacts.

By using such an RF tag, it is possible to record various information related to the article to which the tag is attached, such as the name and identification symbol of the article, the content, the composition, the manager, the user, the usage state, the usage situation, etc. It is possible to accurately read and write a wide variety of information that could not be printed and displayed on the surface of the label, such as characters and barcodes, simply by attaching a small and thin tag to the article.
Here, among such RF tags, a general-purpose RF tag called an inlay (inlet) is widely used in which an IC chip and an antenna are simply film-coated. This type of inlay has been widely used in recent years because it 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.

However, since such general-purpose inlays are simply film-coated IC chips and antennas, if they are left as they are, failures, malfunctions, damages, etc. may occur due to impacts applied from the outside. For example, pallets and containers for cargo are constantly subjected to physical and mechanical external forces and impacts, and in the case of RF tags that are attached to such objects and used, there is a risk of failure or damage if the inlay is left as it is.
For this reason, for RF tags used in environments where such external forces are likely to be applied, general-purpose inlays are housed in predetermined covers, cases, housings, etc., to protect the inlays from physical and mechanical impacts.

For example, Patent Literature 1 proposes an RFID tag in which a general-purpose inlay is sandwiched between protective metal plates having a U-shaped cross section for protection.
Further, Patent Document 2 proposes an RFID tag in which a general-purpose inlay sealed with a non-conductive material is embedded in a hollow slot of a metal holder.
By housing and sealing the general-purpose inlay in the protective plate or holder in this way, the inlay can be protected from the surrounding environment, and in particular, the inlay can be protected from failure or breakage due to external physical and mechanical forces, shocks, collisions, etc. applied from the outside.

Japanese Patent Application Laid-Open No. 2011-204130 JP 2007-135183 A

However, in the techniques proposed in Patent Documents 1 and 2, no consideration is given to antennas provided in general-purpose inlays.
A general-purpose inlay basically includes an IC chip and an antenna section including a loop circuit arranged near the periphery of the IC chip, and the antenna section constitutes a dipole antenna made of a conductor extending in both left and right directions of the IC chip (loop circuit).
Such a dipole antenna is formed symmetrically on both sides of the IC chip so that the conductors forming the antenna have a predetermined length, for example, a length of 1/2 wavelength.

For this reason, if the general-purpose inlay is used as it is, at least a space for disposing and storing the length of the dipole antenna is required.
The techniques of Patent Documents 1 and 2 do not consider the dipole antenna as described above, and have a structure in which the entire inlay is simply housed in a metallic protection plate or holder.
Therefore, the dimensions of the metal protection plate and holder including the inlay must exceed the length of the dipole antenna of the inlay (e.g., 1/2 wavelength), which hinders the miniaturization of RF tags and the freedom of design.

Moreover, in Patent Documents 1 and 2, no consideration is given to providing an auxiliary antenna for the general-purpose inlay.
When a general-purpose inlay is used as an RF tag, by further laminating an auxiliary antenna, the wireless communication distance of the general-purpose inlay can be increased and the frequency band can be widened.
However, if such an inlay and an auxiliary antenna are housed in a metallic protective plate or holder as proposed in Patent Documents 1 and 2, the inlay and the auxiliary antenna as a whole are electrically shielded and blocked by the metallic case, which causes a problem that the auxiliary antenna cannot function effectively.

As a result of diligent research, the applicant and inventor of the present application have conceived of an RF tag invention that is capable of effectively protecting the inlay from the surrounding environment without being restricted by the size of the inlay's antenna, while utilizing the function of the auxiliary antenna to enable good wireless communication of the inlay.

That is, the present invention has been proposed in order to solve the problems of the conventional technology as described above, and relates to an RF tag that can improve the communication characteristics of the inlay by the auxiliary antenna while effectively protecting the inlay from physical and mechanical external forces, impacts, etc., without being restricted by the size and shape of the antenna provided in the inlay, by arranging a metal auxiliary antenna that functions as a protective cover of the inlay over the inlay.

To achieve the above object, the RF tag of the present invention comprises: an inlay comprising at least an IC chip and a loop circuit electrically coupled to the IC chip; a first auxiliary antenna arranged so as to overlap the IC chip and the loop circuit of the inlay; a second auxiliary antenna arranged relative to the inlay so as not to overlap at least the IC chip; It is arranged so as not to overlap at least a part of the inlay and/or the second auxiliary antenna on the side opposite to the surface, and the inlay, the first auxiliary antenna and the second auxiliary antenna are electromagnetically coupled.

According to the present invention, by arranging a metal auxiliary antenna that functions as a protective cover for an inlay provided with an IC chip and a loop circuit over the inlay, it is possible to effectively protect the inlay from physical and mechanical external forces, impacts, etc., and improve the communication characteristics of the inlay by the auxiliary antenna, without being restricted by the dimensions, shape, etc. of the antenna provided on the inlay.
Therefore, according to the present invention, the RF tag can be suitably used as an RF tag for objects to which physical force and shock are often applied from the outside while ensuring the miniaturization of the RF tag and the degree of freedom in design. In particular, it is possible to effectively protect an IC chip that is difficult to restore its function as an RF tag when destroyed by physical or mechanical external force, impact, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view showing an RF tag according to an embodiment of the present invention, in which (a) shows the completed state of the RF tag, and (b) shows the disassembled state of the inlay, first/second auxiliary antennas, and dielectric layer that constitute the RF tag. (a) and (b) are plan views schematically showing the arrangement relationship of each component of the RF tag according to one embodiment of the present invention. (c) is a side view schematically showing the lamination relationship of each component of the RF tag according to one embodiment of the present invention. 4 is a line graph showing the relationship between communication distance and frequency, which shows the communication characteristics of the RF tag according to one embodiment of the present invention. (a) to (d) are line graphs showing changes in the peak value of the communication distance and frequency when the dimensions of the first/second auxiliary antennas are changed, respectively showing the communication characteristics of the RF tag according to one embodiment of the present invention, 4(a) to 4(d) are plan views schematically showing an example in which the planar arrangement positions of the inlay and first/second auxiliary antennas of the RF tag according to one embodiment of the present invention are changed. FIG. 4(a) to 4(d) are side views schematically showing examples in which the stacking positions of the constituent elements of the RF tag according to the embodiment of the present invention are varied. FIG. 2 is a plan view showing a planar layout example of a second auxiliary antenna when the configuration pattern of the inlay antenna section of the RF tag according to the embodiment of the present invention is different, in which (a) is a case where the inlay antenna section constitutes a dipole antenna, (b) is a case where the inlay antenna section constitutes a monopole antenna, and (c) is a case where the inlay antenna section consists only of a loop circuit. 8A to 8C are plan views schematically showing other examples in which the planar arrangement positions of the inlay and the first/second auxiliary antennas of the RF tag according to the embodiment of the present invention are different; FIG.

An embodiment of an RF tag according to the present invention will be described below with reference to the drawings.
FIG. 1 is an external view showing an RF tag 1 according to an embodiment of the present invention, (a) is a perspective view of the completed RF tag 1, and (b) is an exploded perspective view of an inlay 10, first/second auxiliary antennas 20 and 30, a dielectric layer 40, and a dielectric layer 50 (second dielectric layer) that constitute the RF tag 1.
2A and 2B are plan views schematically showing the arrangement relationship between the inlay 10 and the first/second auxiliary antennas 20 and 30, and FIG.

As shown in these figures, the RF tag 1 according to the present embodiment has a structure in which each component consisting of an inlay 10 constituting an RF tag for wireless communication, first/second auxiliary antennas 20 and 30, and dielectric layers 40 and 50 is vertically stacked.
The first auxiliary antenna 20 arranged on the uppermost surface of the RF tag 1 in the stacking direction functions as a protective cover (top cover) that protects the inlay 10 arranged inside the tag from the external environment.
In addition, the second auxiliary antenna 30 arranged over the inlay 10 functions as an antenna for the inlay 10 together with the first auxiliary antenna 20, so that even if the inlay 10 is covered with the first/second auxiliary antennas 20, 30, good wireless communication characteristics can be obtained without impairing the communication function.

In particular, in this embodiment, the first auxiliary antenna 20, which serves as the top cover (protective cover) of the RF tag 1 and is laminated on one surface (upper surface) of the dielectric layers 40 and 50, which serve as base materials on which the inlay 10 is placed and fixed, is formed of a metal member (metal plate), thereby improving the durability, impact resistance, pressure resistance, etc. against physical forces such as impact and pressure applied from the outside to the RF tag 1, thereby effectively preventing the inlay 10 arranged inside from being broken or damaged due to an external force or impact. .
Furthermore, by arranging the first auxiliary antenna 20 functioning as a protective cover for such an RF tag 1 so as not to overlap at least part of the inlay 10 and/or the second auxiliary antenna 30, and by arranging the second auxiliary antenna 30 so as not to overlap at least the IC chip 11 with respect to the inlay 10, the first/second auxiliary antennas 20 and 30 function as antennas for the inlay 10, and the communication characteristics of the RF tag 1 can be maintained and improved in a favorable state.

Specifically, as shown in FIGS. 1 and 2, the RF tag 1 according to the present embodiment includes an inlay 10 having an IC chip 11 and an antenna unit 12, planar first/second auxiliary antennas 20 and 30 arranged on the same plane in an insulated state with respect to the inlay 10, and dielectric layers 40 and 5 functioning as dielectric constant adjustment layers for the mounted inlay 10 as well as serving as base layers on which the inlay 10 and the first/second auxiliary antennas 20 and 30 are arranged and mounted. 0.
The first/second auxiliary antennas 20 and 30 are each formed in a predetermined shape and size corresponding to the communication frequency of the inlay 10. The first/second auxiliary antennas 20 and 30 are arranged at predetermined positions with respect to the inlay 10 (see FIGS. 2(a) to 2(c)) and mounted on the dielectric layers 40 and 50.
Each part will be described in detail below.

[Inlay]
The inlay 10 constitutes an RF tag that wirelessly reads, writes, and reads/writes predetermined information from/to a reader/writer (reader/writer) (not shown).
Specifically, the inlay 10 has an IC chip 11 and an antenna section 12 electrically connected to and connected to the IC chip 11. After the IC chip 11 and the antenna section 12 are mounted on and formed on a sheet of sealing film 13 made of, for example, PET resin as a base material, another sheet of sealing film 13 is overlapped and sandwiched between the two sealing films 13 for sealing and protection.
In the example shown in FIG. 1, the IC chip 11 and the antenna section 12 consisting of dipole antennas extending on both sides in the longitudinal direction of the tag of the IC chip 11 are sandwiched and sealed with rectangular sealing films 13 to form a rectangular inlay 10.

The IC chip 11 is composed of a semiconductor chip such as a memory, and can record data of several hundred bits to several kilobits, for example.
An antenna portion 12 made of a conductor pattern is connected to both the left and right sides of the IC chip 11, and a part of the antenna portion 12 is formed as a loop circuit (loop portion) 11a made of a loop-shaped circuit conductor so as to surround the periphery of the IC chip 11. An antenna section 12 forming a dipole antenna is connected to both left and right sides of the IC chip 11 via the loop circuit 11a.

Via this antenna unit 12 and first/second auxiliary antennas 20 and 30, which will be described later, reading and writing (data calling, registration, deletion, updating, etc.) are performed by wireless communication between the IC chip 11 and a reader/writer (not shown), and the data recorded in the IC chip 11 is recognized.
As the data recorded in the IC chip 11, arbitrary data such as product identification code, name, weight, content, manufacturer/seller name, manufacturing location, manufacturing date, expiration date, etc. can be recorded, and rewriting is also possible.

The antenna section 12 including the loop circuit 11a is formed by forming a metal thin film such as a conductive ink or a conductive aluminum vapor deposition film into a predetermined shape and size (length and area) by etching or the like on the surface of a sheet of sealing film 13 that serves as a base material.
Here, the antenna section 12 is formed so that the length of the dipole antenna portion extending on both left and right sides of the IC chip 11 is an integer fraction of the wavelength of the radio frequency of the inlay 10, for example, approximately 1/2 or approximately 1/4 of the wavelength of the radio frequency.
In the inlay 10 shown in FIGS. 1 and 2, the antenna portion 12 is bent twice so that the longitudinal direction extending to both left and right sides of the IC chip 11 is substantially perpendicular, so that both ends of the antenna portion 12 in the longitudinal direction are formed into a hook shape extending toward the loop circuit 11a, and are formed to have a predetermined antenna length.

Further, in the antenna section 12 according to the present embodiment, the central portion of the metal thin film is formed in a hollow/punched shape in which the metal thin film does not exist along the longitudinal direction from the vicinity of the IC chip 11 to both ends in the longitudinal direction, and the conductive portion of the antenna portion 12 is formed in an annular/loop shape.
Note that the antenna unit 12 provided in the inlay 10 is not limited to a dipole antenna extending to both the left and right sides of the IC chip 11, and can be configured as a monopole antenna extending only to either the left or right side of the IC chip 11, as described later (see FIGS. 7 and 8).
Further, it is possible to construct an antenna consisting only of the loop circuit 11a without a dipole antenna or a monopole antenna (see FIGS. 7 and 8).

The sealing film 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. It is preferable that the IC chip 11 and the antenna section 12 to be sealed be made of a transparent PET resin or the like that is visible from the outside.
In addition, the film surface on one side of the sealing film 13 can be provided with an adhesive layer/bonding layer so that it can be attached to a base material or an article.
The sealing film 13 may be sealed with the IC chip 11 and the antenna section 12 sandwiched between the two sealing films 13. Alternatively, one sheet of the sealing film 13 may be folded to sandwich and seal the antenna section 12 including the IC chip 11 and the loop circuit 11a.

As the communication frequency band used in the inlay 10, the RF tag 1 of the present embodiment targets the 920 MHz band (915-930 MHz: 15 MHz width) belonging to the so-called UHF band.
Frequency bands generally used in RF tags include several types of frequency bands, such as a band below 135 kHz, a 13.56 MHz band, an 860 M to 960 MHz band belonging to the UHF band, and a 2.45 GHz band. The communication distance over which wireless communication is possible differs depending on the frequency band used, and the optimum antenna length and wiring pattern also differ depending on the frequency band.

In addition, in Japan, due to the revision of the Radio Law, RF tags have been shifted from the 950 MHz band (950-958 MHz: 8 MHz width) that had been used until now to the 920 MHz band (915-930 MHz: 15 MHz width), expanding the usable frequency band.
Therefore, in this embodiment, the inlay 10 can be miniaturized, and the first and second auxiliary antennas 20 and 30, which will be described later, are formed in a predetermined size. Therefore, the UHF band is targeted because the wavelength is short and the antenna can be miniaturized.
However, if there are no restrictions on the size of the inlay 10 or the first/second auxiliary antennas 20 and 30, the technical concept of the present invention can of course be applied to frequency bands other than the 920 MHz band and the UHF band.

[1st auxiliary antenna]
The first auxiliary antenna 20 is a planar member laminated on the uppermost surface on one side of the RF tag 1, and is made of a predetermined metal material (metal plate).
By providing such a metallic first auxiliary antenna 20, one surface (upper surface) side of the RF tag 1 is protected by the metal plate, and the durability, impact resistance, weather resistance, heat resistance, waterproofness, etc. of the RF tag can be enhanced.
In addition, the metal first auxiliary antenna 20 can function as an antenna for the inlay 10 arranged inside the RF tag 1, and the communication characteristics of the RF tag 1 can be maintained and improved in a good state.

Specifically, as shown in FIG. 1, the first auxiliary antenna 20 is made of a plate-like member made of a metal material, and the plate-like member is a rectangular metal plate with no cutouts or openings.
By arranging the rectangular first auxiliary antenna 20 with no cutouts or openings so as to overlap the IC chip and the loop circuit in this way, it is possible to prevent physical and mechanical external forces and impacts through the cutouts and openings, and to effectively protect the IC chip, etc., which is difficult to restore its function as an RF tag when destroyed by such external forces and impacts.

In addition, as shown in FIGS. 2(a) to 2(c), the first auxiliary antenna 20 is formed so that its longitudinal dimension is shorter than the dielectric layers 40 and 50, which are the base materials of the inlay 10 and the second auxiliary antenna 30.
Accordingly, the first subantenna 20 can be stacked on the dielectric layers 40 and 50 so as not to overlap at least part of the inlay 10 and the second subantenna 30 stacked on the dielectric layers 40 and 50 .
As a result, even if the metal first auxiliary antenna 20 is placed on the uppermost layer of the RF tag 1, at least a part of the inlay 10 and the second auxiliary antenna 30 can be exposed so as not to be covered by the first auxiliary antenna 20, i.e., the first metal auxiliary antenna 20 can be exposed (see FIG. 2A), and the antenna section 12 of the inlay 10 and the second auxiliary antenna 30 can effectively function as the antenna of the RF tag 1.

In FIG. 2(a), the second auxiliary antenna 30 exposed from the outer edge of the first auxiliary antenna 20 is shown so as to be directly visible for easy understanding. However, in the actual RF tag 1, since the dielectric layer 40 is laminated on the upper surface of the inlay 10 and the second auxiliary antenna 30 (see FIG. 2(b)), it cannot be directly visually recognized from the outside.
Therefore, "exposed" in this specification means that the inlay 10 and the second auxiliary antenna 30 are exposed from the end/outer edge of the first auxiliary antenna 20, and does not mean that they are exposed on the surface of the RF tag 1.

By arranging and fixing the first auxiliary antenna 20 on the surface (uppermost surface) of the RF tag 1, the first auxiliary antenna 20, the inlay 10 and the second auxiliary antenna 30 arranged inside the RF tag 1 are stacked in a predetermined position.
With such a stacked arrangement configuration, the first auxiliary antenna 20 and the IC chip 11 of the inlay 10 are arranged facing each other through the dielectric layer 40 and the second auxiliary antenna 30 as shown in FIG.

Specifically, the first auxiliary antenna 20 functions as an antenna for improving and adjusting the communication characteristics of the inlay 10 together with the antenna section 12 provided in the inlay 10 or in place of the antenna section 12. The first auxiliary antenna 20 is composed of a planar conductive member laminated on one side (upper surface side) of the inlay 10, and is arranged in an insulated state from the inlay 10 by the sealing film 13 that seals the inlay 10 with resin and the dielectric layer 40.
That is, the first auxiliary antenna 20 made of a conductive material such as metal is physically insulated from the inlay 10 because the inlay 10 is entirely resin-sealed with the sealing film 13 and the dielectric layer 40 is laminated between the inlay 10 and the first auxiliary antenna 20.

By stacking and arranging such a first auxiliary antenna 20 on one side of the inlay 10, the first auxiliary antenna 20 and the IC chip 11 of the inlay 10 are arranged facing each other via the sealing film 13 and the dielectric layer 40, and electromagnetic connection is established by so-called capacitor coupling.
Thus, by stacking the first auxiliary antenna 20 on the inlay 10 in the vertical direction (height direction), the first auxiliary antenna 20 forms a two-dimensional antenna together with the antenna section 12 including the loop circuit 11a of the inlay 10 or in place of the antenna section 12, and the first auxiliary antenna 20 functions as a booster of communication radio waves, thereby adjusting and improving the communication characteristics of the inlay 10.

Here, as shown in FIG. 2(a), the first auxiliary antenna 20 is preferably formed so that the length in the longitudinal direction is approximately half the wavelength of the radio frequency of the inlay 10 (half wavelength).
The overall size (length) of the RF tag 1 is almost defined by the length of the first auxiliary antenna 20 .

Therefore, if the length of the first auxiliary antenna 20 is set to 1/2 wavelength, the overall size (length) of the RF tag 1 can be set to approximately 1/2 wavelength (half wavelength) or a slightly larger (longer) size while ensuring good communication characteristics.
In addition, in order to reduce the overall length of the RF tag 1, for example, the size of the first auxiliary antenna 20 is such that the total length of two adjacent short and long sides is the wavelength of the radio frequency of the inlay 10.

With such a configuration, the first auxiliary antenna 20 has a length approximately half the wavelength of the radio frequency of the inlay 10, and good communication characteristics can be obtained.
Specifically, for example, when the target inlay 10 has a communication frequency of 920 MHz, λ≈326.0 mm and λ/2≈163.0 mm. Therefore, the first auxiliary antenna 20 is formed so that the length of the long side or the total length of the two sides including the long side and the short side is approximately 163.0 mm.

As described above, the inlay 10 has an IC chip 11 and an antenna portion 12 electrically connected to and connected to the IC chip 11. After the IC chip 11 and the antenna portion 12 are mounted and formed on a sheet of sealing film 13 made of, for example, PET resin as a base material, another sheet of the sealing film 13 is overlapped and sandwiched between the two sealing films 13 to be sealed and protected.
A dielectric layer 40 is interposed between the inlay 10 and the first auxiliary antenna 20, and a dielectric 50 is interposed on the mounting surface side.
Therefore, in the inlay 10 according to the present embodiment, the structure in which the PET layer or the dielectric layer is interposed between the first auxiliary antenna 20, which is a conductor, and the antenna section 12 of the inlay 10, produces a wavelength shortening effect, and the apparent wavelength may be shortened. Their dielectric constants are approximately "2 to 4". Since the wavelength shortening rate is √(relative permittivity), it is about √(2 to 4).
For this reason, the length of the long side of the first auxiliary antenna 20 or the length of the two sides of the long side and the short side are also approximate values, and it is sufficient if the length is, for example, a value of approximately λ/2.

As described above, by making the first auxiliary antenna 20 that covers the surface of the RF tag 1 made of metal, the inside of the housing can be protected against mechanical and physical external forces and impacts applied to the RF tag 1 by the strength, durability, and impact resistance of the first auxiliary antenna 20 made of metal.
By providing the first auxiliary antenna 20 made of metal, the first auxiliary antenna 20 can function as an antenna for the inlay 10 of the RF tag 1, and wireless communication of the RF tag 1 can be performed even if the inlay 10 does not have a dipole antenna.

Here, as the metal material forming the first auxiliary antenna 20, for example, steel, copper, stainless steel, aluminum alloy, zinc alloy, etc. can be used.
The reason why the RF tag 1 is made of metal is to obtain durability and impact resistance against mechanical and physical external forces applied to the surface of the RF tag 1, and to configure the auxiliary antenna of the inlay 10 with the metal member arranged on the surface of the RF tag 1.
Therefore, in order to achieve such a purpose, if the first auxiliary antenna 20 arranged on the front side (top side) of the RF tag 1 is made of metal, the back side (bottom side) of the RF tag 1 may be made of metal or non-metal (for example, made of synthetic resin) (see FIG. 6 described later).

[Second auxiliary antenna]
The second auxiliary antenna 30 functions as an extra antenna for improving and adjusting the communication characteristics of the inlay 10 described above, and as shown in FIGS. That is, the inlay 10 is entirely resin-sealed with the sealing film 13 and is physically insulated from the second auxiliary antenna 30 made of a conductive member.
By arranging the second auxiliary antenna 30 in the vicinity of the inlay 10, the second auxiliary antenna 30 and the IC chip 11 of the inlay 10 are arranged facing each other via the sealing film 13, and electromagnetic connection is established by so-called capacitor coupling.

Then, as shown in FIGS. 2B and 2C, the second auxiliary antenna 30 is arranged with respect to the inlay 10 so as not to overlap at least the IC chip 11 of the inlay 10, and at least part of the inlay 10 and/or the second auxiliary antenna 30 is arranged so as not to overlap the first auxiliary antenna 20.
In the example shown in the figure, the second auxiliary antenna 30 is arranged along the longitudinal direction of the inlay 10 so as to overlap only the antenna section 12 on the right side of the inlay 10, and not overlap the IC chip and the antenna section 12 on the left side (see FIG. 2(b)).
Furthermore, with respect to such an inlay 10 and a second auxiliary antenna 30, the first auxiliary antenna 20 is arranged along the longitudinal direction so as to overlap the entire inlay 10 and the left portion of the second auxiliary antenna 30. As a result, the first auxiliary antenna 20 does not overlap the right end of the second auxiliary antenna 30, and a part of the second auxiliary antenna 30 is exposed, for example, by about 10 to 20 mm (see FIG. 2(a)).
In FIG. 2A, the second auxiliary antenna 30 exposed from the outer edge of the first auxiliary antenna 20 is shown to be directly visible for easy understanding, but in the actual RF tag 1, the dielectric layer 40 is laminated on the upper surface of the second auxiliary antenna 30, so it cannot be directly visible from the outside.

In this way, the second auxiliary antenna 30 is arranged on the inlay 10 so as to face each other on the same plane, and is arranged so as not to overlap the IC chip 11 of the inlay 10. Furthermore, by arranging a part of the second auxiliary antenna 30 (or the inlay 10) to be exposed without overlapping the first auxiliary antenna 20, the second auxiliary antenna 30 can effectively function as an antenna of the inlay 10 together with the first auxiliary antenna 20.
That is, the antenna section 12 of the inlay 10 and the first/second auxiliary antennas 20 and 30 constitute a two-dimensional antenna, and the second auxiliary antenna 30 functions as a communication radio wave booster together with the first auxiliary antenna 20, so that the communication characteristics of the inlay 10 can be adjusted and improved.

Here, the second auxiliary antenna 30 can be formed, for example, by molding a metal thin film such as a conductive ink or a conductive aluminum deposited film formed on the surface of a film that serves as a base material such as PET resin into a predetermined shape and size (length and area) by etching, punching, or the like.
In this embodiment, as shown in FIGS. 2(a) to 2(c), the second auxiliary antenna 30 is formed into a rectangular/planar shape having long sides and short sides approximately the same length as the long sides and short sides of the inlay 10.
Further, the second auxiliary antenna 30 is formed so that both the long and short sides thereof are shorter than the long and short sides of the dielectric layers 40 and 50 so as not to protrude from the dielectric layers 40 and 50 serving as the base material. As shown in FIGS.

If the second auxiliary antenna 30 overlaps the loop circuit 11 a of the inlay 10 , especially the IC chip 11 , the conductive member forming the second auxiliary antenna 30 may impair the communication characteristics of the IC chip 11 .
That is, a loop circuit 11a is formed in the vicinity of the IC chip 11 of the inlay 10, and this loop circuit 11a is provided for the purpose of impedance matching and for performing communication using a magnetic field component.
On the other hand, if the second auxiliary antenna 30 and the inlay 10 are too far apart, electrical connection by so-called capacitor coupling via the sealing film 13 becomes insufficient, and good communication characteristics cannot be obtained.

Therefore, in this embodiment, the second auxiliary antenna 30 is arranged so as not to overlap at least the IC chip 11 of the inlay 10 .
In addition, the second auxiliary antenna 30 overlaps a portion of the inlay 10 excluding the IC chip 11, i.e., a portion of the antenna section 12 including the loop circuit 11a, through a sealing film 13 that covers the entire inlay 10. The second auxiliary antenna 30 and the IC chip 11 of the inlay 10 are arranged facing each other through the sealing film 13 and electromagnetically connected by capacitor coupling.
With such an arrangement configuration, the second auxiliary antenna 30 can secure a large antenna area together with the antenna section 12 of the inlay 10 without hindering the communication function of the inlay 10, thereby maximizing the antenna gain.

It should be noted that the current flowing through the second auxiliary antenna 30 when data is read from or written to the inlay 10 flows only through the peripheral portion of the planar second auxiliary antenna 30 (skin effect).
Therefore, as long as the second auxiliary antenna 30 has the size and shape described above, the planar portion can be formed in, for example, a mesh shape or a lattice shape.
By forming the second auxiliary antenna 30 in a mesh shape or the like in this way, the function as an antenna is not impaired by the skin effect, and the area of the entire conductor portion of the second auxiliary antenna 30 can be reduced, the conductive material such as the conductive ink that forms the second auxiliary antenna 30 can be reduced, and the cost of the RF tag 1 can be further reduced.

[Dielectric layer]
The dielectric layers 40 and 50 serve as base layers on which the above-described inlay 10 and second auxiliary antenna 30 are mounted, and are members that function as dielectric constant adjustment layers for the mounted inlay 10 . In this embodiment, two dielectric layers 40 and 50 of the same shape and size are provided.
Specifically, the dielectric layers 40 and 50 are formed in the same shape and size as the inlay 10 and the second auxiliary antenna 30 arranged so as not to overlap the IC chip 11 so that the inlay 10 and the second auxiliary antenna 30 can be arranged and mounted on the same plane without protruding (see FIG. 2). The dielectric layers 40 and 50 define the external size of the RF tag 1 (see FIGS. 1 and 2).

In the two dielectric layers 40 and 50, first, the inlay 10 and the second auxiliary antenna 30 are stacked on the same plane on one side (upper side in FIG. 1) of the dielectric layer 50 on the lower layer side (bottom side) of the RF tag 1. At this time, the second auxiliary antenna 30 is arranged so as not to overlap at least the IC chip 11 of the inlay 10 .
Then, the first auxiliary antenna 20 on the upper layer side (upper surface side) of the RF tag 1 is superimposed on one surface (upper surface) of the dielectric layer 40 on which the inlay 10 and the second auxiliary antenna 30 are mounted.

As a result, the inlay 10 and the second auxiliary antenna 30 are sandwiched and sealed between the two dielectric layers 40 and 50 and protected from the outside.
As described above, in the present embodiment, the two dielectric layers 40 and 50 are formed in the shape of a case (housing) that covers the entire laminated inlay 10 and the second auxiliary antenna 30. By protecting the inlay 10 and the second auxiliary antenna 30 with the case-shaped dielectric layers 40 and 50, the weather resistance, heat resistance, and waterproofness of the RF tag 1 are enhanced.

The dielectric layers 40 and 50 configured as such a case (housing) are inseparably fixed and adhered by, for example, a fitting structure (not shown), ultrasonic welding, adhesive, or the like.
Further, the inlay 10 and the second auxiliary antenna 30 arranged between the dielectric layers 40 and 50 and the first auxiliary antenna 20 arranged on the surface of the dielectric layer 40 are also fixed and adhered to the dielectric layers 40 and 50 by a fitting structure, an adhesive, or the like so as not to fall off.
Among the dielectric layers 40 and 50, the dielectric layer 50 on the bottom side of the RF tag 1 is provided with an adhesive material such as a double-sided tape (adhesive tape) or a plate-shaped magnet, although not shown, so that it can be stuck and attached to the surface of the metal article to be attached by the adhesive force of the adhesive material or the magnetic force of the magnet.
As a result, the RF tag 1 is arranged and fixed to the surface of the metal article so that the dielectric layer 50 is attached and fixed to the surface of the object to be attached and is not easily detached or peeled off.

Here, as the dielectric layers 40 and 50 according to the present embodiment as described above, thermoplastic resins such as polycarbonate resins, acrylonitrile-butadiene-styrene copolymer (AES) resins, polypropylene resins, polyethylene resins, polystyrene resins, acrylic resins, polyester resins, polyphenylenine sulfide resins, acrylonitrile-butadiene-styrene copolymer (ABS) resins, polyvinyl chloride resins, polyurethane resins, fluorine resins, silicone resins, and other resin materials such as thermoplastic elastomers. Alternatively, it can be formed from a crosslinked polyolefin foam such as foamed polyethylene, acrylic foam, or foamed polypropylene.
Further, each of the dielectric layers 40 and 50 can be composed of a single belt-shaped member formed of the resin material or the crosslinked polyolefin foam as described above, or a plurality of (for example, two layers) of belt-shaped members can be laminated to form one dielectric layer 40 or dielectric layer 50.

In addition, the dielectric layers 40 and 50 as described above are formed so as to have a predetermined relative dielectric constant for adjusting the communication characteristics of the inlay 10 stacked together with the second auxiliary antenna 30, so that the dielectric layers 40 and 50 can function as a dielectric constant adjustment layer for the inlay 10 mounted and stacked using the dielectric layers 40 and 50 as base materials.
For example, the dielectric layers 40 and 50 can be formed as a dielectric constant adjustment layer having a dielectric constant suitable for the communication specification of the inlay 10 by forming the dielectric layers 40 and 50 with a predetermined thickness using a predetermined member.

In this way, since the dielectric layers 40 and 50 have a predetermined dielectric constant and thickness, the dielectric layers 40 and 50 can avoid or absorb the influence of the metal to which the RF tag 1 is attached, and as the communication characteristics of the RF tag 1, it is possible to obtain a good communication distance as described later (see FIG. 3).
Therefore, by selecting an appropriate material and thickness for the dielectric layers 40 and 50 in consideration of various conditions such as the type of inlay 10 to be used, the communication characteristics, the article using the RF tag 1, the usage environment, and the usage frequency band, and by selecting or exchanging only the dielectric layer 40, the RF tag 1 can be used for different articles or can be made compatible with different communication frequencies.

[Communication characteristics]
Next, the communication characteristics of the RF tag 1 according to this embodiment configured as described above will be described with reference to FIGS. 3 and 4. FIG.
3 and 4 are line graphs showing the relationship between communication distance and frequency, showing the communication characteristics of the RF tag 1 according to one embodiment of the present invention.
The communication characteristics of the RF tag 1 can be evaluated using a known evaluation method/evaluation system, and the evaluation of the present embodiment described below was performed using a Voyantic Tagformance system as an evaluation system.
In addition, the evaluation was performed not by directly measuring the communication distance, but by a value converted from the radio wave intensity at a constant distance.
Moreover, the measurement was performed by attaching the RF tag 1 to a stainless steel plate (150*100*t2 mm).

The graph shown in FIG. 3 compares the RF tag 1 according to the present embodiment with an RF tag (Comparative Example 1) in which an inlay having a monopole antenna is stored inside, which is proposed in a prior application (Japanese Patent Application No. 2018-138196) filed by the applicant of the present application.
In the figure, the solid line is the RF tag according to Comparative Example 1, the dashed line is the case where the inlay of Comparative Example 1 is moved from directly below the notch portion to directly below the auxiliary antenna (Comparative Example 2), and the dashed line is the RF tag 1 according to the present embodiment.

As shown in these graphs, it can be seen that the RF tag of Comparative Example 1 achieves a long communication distance in the high frequency band, particularly in the 860-940 MHz band.
On the other hand, in the case of the RF tag of Comparative Example 2, the band in which wireless communication is possible becomes extremely narrow, and the communication distance becomes extremely short (3 m or less), so that it is not practical. This is because the communication function of the inlay is hindered by the auxiliary antenna arranged on the housing surface.

On the other hand, in the RF tag 1 according to the present embodiment, although the communicable frequency band is slightly narrower than that of Comparative Example 1, it can be seen that a long communication distance similar to that of Comparative Example 1 is obtained.
In particular, a communication distance of 10 m or more is obtained in the 920-940 MHz band, and a peak communication distance (approximately 13 m) is obtained in the 920 MHz band.

Graphs shown in FIGS. 4A to 4D all show communication characteristics when the dimensions of the auxiliary antenna are changed in this embodiment.
The graph shown in FIG. 4(a) shows the case where the total length (longitudinal direction) of the first auxiliary antenna 20 is changed, and it can be seen that the shorter the total length of the first auxiliary antenna 20, the more the peak of the communication distance shifts to a higher frequency band.
The graph shown in FIG. 4B shows a case in which the overall width (transverse direction) of the first auxiliary antenna 20 is changed, and it can be seen that the longer the overall width of the first auxiliary antenna 20, the more the peak of the communication distance shifts to the lower frequency band.

The graph shown in FIG. 4(c) shows a case in which the total width (transverse direction) of the second auxiliary antenna 30 is changed to change the area of the second auxiliary antenna 30 exposed from the first auxiliary antenna 20, and it can be seen that the communication distance increases particularly in the low frequency band as the exposed area of the second auxiliary antenna 30 increases.
The graph shown in FIG. 4(d) shows the case where the placement position of the same second auxiliary antenna 30 is moved to change the area of the second auxiliary antenna 30 exposed from the first auxiliary antenna 20, and it can be seen that the communication distance increases as the exposed area of the second auxiliary antenna 30 increases.
Also, when the entire second auxiliary antenna 30 is hidden by the first auxiliary antenna 20 and the exposed area is zero, the communicable frequency band and the communication distance become extremely low as in the case of Comparative Example 2 in FIG.

From the results of FIGS. 3 and 4 above, it can be seen that by changing the dimensions (total length and total width) of the first auxiliary antenna 20, the communicable frequency band can be moved and adjusted, and by changing the area where the second auxiliary antenna 30 is exposed from the first auxiliary antenna 20, the communication distance can be adjusted and changed.
Therefore, when setting/adjusting the frequency band/communication distance, roughly adjust the total length/width of the first/second auxiliary antennas 20 and 30, and then finely adjust the position of the second auxiliary antenna 30 by changing/adjusting it.

[Plane arrangement pattern]
Next, the planar layout pattern of the inlay 10 and the first/second auxiliary antennas 20 and 30 in the RF tag 1 of the embodiment will be described with reference to FIG.
FIGS. 5A to 5D are plan views schematically showing examples in which the inlay 10 and the first/second auxiliary antennas 20 and 30 of the RF tag 1 according to this embodiment are arranged at different positions.
In the example shown in the figure, the RF tag 1 is formed such that the lengthwise and widthwise dimensions of the first auxiliary antenna 20 are smaller than the dielectric layers 40 and 50 that serve as base materials for the inlay 10 and the second auxiliary antenna 30.

Specifically, for example, the first auxiliary antenna 20 is formed to have a longitudinal direction of about 110 mm and a lateral direction of about 20 mm corresponding to a half wavelength of the communication frequency of 920 MHz of the target inlay 10, and the dielectric layers 40 and 50 serving as base materials are formed to have a size slightly larger than that, for example, a longitudinal direction of about 130 mm and a lateral direction of about 30 mm.
Also, the inlay 10 and the second auxiliary antenna 30 can be arranged without protruding above the dielectric layers 40 and 50, and the longitudinal and transverse dimensions are set to be smaller than those of the dielectric layers 40 and 50 and the first auxiliary antenna 20 so that the first auxiliary antenna 20 can be arranged overlapping the IC chip and the loop circuit 11a of the inlay 10 (see FIG. 2).

Accordingly, the first subantenna 20 can be stacked on the dielectric layers 40 and 50 so as not to overlap at least part of the inlay 10 and the second subantenna 30 stacked on the dielectric layers 40 and 50 .
A specific example of the planar arrangement pattern of the first auxiliary antenna 20, the inlay 10, and the second auxiliary antenna 30 will be described below with reference to FIG.
In FIG. 5, the inlay 10 and the second auxiliary antenna 30 exposed from the outer edge of the first auxiliary antenna 20 are shown so as to be directly visible in order to facilitate understanding.

In the example shown in FIG. 5A, the inlay 10 and the second auxiliary antenna 30 are partially exposed from both ends in the longitudinal direction of the first auxiliary antenna 20. The left end of the first auxiliary antenna 20 is exposed from the left end of the inlay 10, and the right end of the second auxiliary antenna 30 is exposed from the right end of the first auxiliary antenna 20. The exposed length of the inlay 10/second auxiliary antenna 30 can be set to, for example, about 10 to 20 mm.
In the example shown in FIG. 5B, only part of the second auxiliary antenna 30 is exposed from one longitudinal end of the first auxiliary antenna 20, and the right end of the second auxiliary antenna 30 is exposed from the right end of the first auxiliary antenna 20. The exposed length of the second auxiliary antenna 30 can also be set to about 10 to 20 mm, for example.

In the example shown in FIG. 5C, only a portion of the inlay 10 is exposed from the other longitudinal end of the first auxiliary antenna 20, and the left end of the antenna portion 12 of the inlay 10 is exposed from the left end of the first auxiliary antenna 20. The exposed length of the inlay 10 can also be set to about 10 to 20 mm, for example.
In the example shown in FIG. 5D, only part of the second auxiliary antenna 30 is exposed from one end of the first auxiliary antenna 20 in the short direction, and the lower end of the second auxiliary antenna 30 is exposed over the entire longitudinal direction from the lower end of the first auxiliary antenna 20. The exposed width of the second auxiliary antenna 30 can be set to, for example, about 5 to 10 mm.
The arrangement/exposure pattern of the first auxiliary antenna 20, the inlay 10, and the second auxiliary antenna 30 as described above is merely an example, and other arrangement/exposure patterns other than the pattern shown in FIG.

[Lamination arrangement pattern]
Next, the stacking arrangement pattern of the RF tag 1 according to this embodiment will be described with reference to FIG.
FIGS. 6A to 6D are side views schematically showing lamination arrangement patterns of respective components of the RF tag 1 according to this embodiment.
As shown in the figure, the RF tag 1 according to the present embodiment consists of five elements [inlay 10, first/second auxiliary antennas 20, 30, dielectric layers 40, 50], which are attached and fixed to an object to be attached (back metal body 100, back non-metal body 200).

As shown in FIGS. 6A and 6B, the five elements constituting the RF tag 1 may be stacked in the order of [back metal body 100→dielectric layer 50→inlay 10→second auxiliary antenna 30→dielectric layer 40→first auxiliary antenna 20]. 1 auxiliary antenna 20].
In addition, as shown in FIG. 6(c), the dielectric layers 40 and 50 can be configured to integrally house and seal the inlay 10 and the second auxiliary antenna 30 inside by in-mold molding or the like.
Furthermore, as shown in FIG. 6(d), the object to which the RF tag 1 is attached is not limited to metallic articles/objects, but also non-metallic articles/objects such as those made of synthetic resin (back non-metallic body 200).

[Inlay antenna part]
Next, the configuration pattern of the antenna section 12 of the inlay 10 of the RF tag 1 according to this embodiment will be described with reference to FIG.
7A and 7B are plan views showing examples of planar arrangement of the second auxiliary antenna when the configuration pattern of the antenna section 12 of the inlay 10 according to the present embodiment is different. FIG. 7A shows the case where the antenna section 12 constitutes a dipole antenna, FIG.
As shown in FIG. 7, the antenna unit 12 provided in the inlay 10 can be configured as a dipole antenna extending to both the left and right sides of the IC chip 11 (see FIG. 7A), or can be configured as a monopole antenna extending only to one of the left and right sides of the IC chip 11 (see FIG. 7B), or can be configured as an antenna consisting only of a loop circuit 11a that does not include a dipole antenna or a monopole antenna (see FIG. 7C).

A general-purpose inlay is generally provided with a dipole antenna made of a conductor extending linearly on both sides (left and right) of the IC chip 11. However, in a dipole antenna, the conductors constituting the antenna are provided symmetrically on both sides of the IC chip so that the length is, for example, 1/2 wavelength. 2 wavelengths) is required, which may limit the miniaturization of the RF tag and the degree of freedom in design.
Further, when the inlay is provided with an auxiliary antenna separately in addition to the antenna provided in the inlay, the auxiliary antenna functions as an antenna of the inlay, so that radio communication can be performed even without a dipole antenna on the inlay side.

Therefore, in the present embodiment, the inlay 10 is configured to have a dipole antenna extending on both sides of the IC chip 11 (loop circuit 11a), a configuration including a monopole antenna, or a configuration including only the loop circuit 11a that does not include a dipole antenna or a monopole antenna. Thus, it is possible to effectively utilize the function of the auxiliary antenna without being restricted by the size and shape of the antenna of the inlay 10, and to enable good wireless communication of the inlay.
The inlay 10 including the antenna section 12 composed only of the monopole antenna and the loop circuit 11a can be configured by, for example, using a general-purpose inlay including a dipole antenna and cutting and removing part or all of the dipole antenna portion. Alternatively, the inlay 10 having a monopole antenna of a predetermined length and shape, or the inlay 10 having only the IC chip 11 and the loop circuit 11a may be manufactured as a dedicated inlay.

[Dipole Antenna]
FIG. 7A shows a case where the antenna section 12 of the inlay 10 is configured as a dipole antenna.
In this case, the second auxiliary antenna 30 only has to be arranged so as not to overlap with the IC chip 11 at least.

[Monopole Antenna]
FIG. 7B shows a case where the antenna section 12 of the inlay 10 is configured as a monopole antenna.
In this case as well, the second auxiliary antenna 30 only needs to be arranged so as not to overlap the IC chip 11 at least. can also
By arranging the second auxiliary antenna 30 over at least part of the monopole antenna and the loop circuit 11a of the antenna section 12 in this way, the communication characteristics of the inlay 10 can be adjusted and improved, and the length of the inlay 10 (RF tag 1) in the longitudinal direction in a plan view can be made smaller (shorter) than the inlay 10 having a dipole antenna.

[Loop circuit only]
FIG. 7(c) shows a case where the antenna section 12 of the inlay 10 does not include a dipole antenna or a monopole antenna, but includes only the loop circuit 11a.
In this case as well, the second auxiliary antenna 30 may be arranged at least so as not to overlap the IC chip 11, and the second auxiliary antenna 30 can be arranged overlapping one edge or both edges of the loop circuit 11a on both the left and right sides of the IC chip 11.
In this case as well, by arranging the second auxiliary antenna 30 overlapping the loop circuit 11a, the second auxiliary antenna 30 functions as the antenna section 12 of the inlay 10, so that the communication characteristics of the inlay 10 (RF tag 1) can be adjusted and improved.

[Other forms]
The embodiment of the arrangement pattern of each component of the RF tag 1 has been described above with reference to FIGS.
In the example shown in FIG. 8(a), when the antenna section 12 of the inlay 10 is configured as a monopole antenna, a small planar second auxiliary antenna 30 is arranged along the lower edge facing the IC chip 11 of the loop circuit 11a.
In the example shown in FIG. 8(b), when the antenna section 12 of the inlay 10 is composed only of the loop circuit 11a, a small linear second auxiliary antenna 30 is arranged overlaid along the lower edge of the loop circuit 11a facing the IC chip 11.

The example shown in FIG. 8C is a case where the linear second auxiliary antenna 30 shown in FIG.
As described above, the configuration and configuration of the second auxiliary antenna 30, which is arranged over the inlay 10, can also be a predetermined configuration and configuration according to the configuration and configuration of the inlay 10 and the antenna unit 12, and the communication characteristics of the inlay 10 can be flexibly and finely adjusted and handled.

As described above, according to the RF tag 1 of the present embodiment, the first auxiliary antenna 20 arranged on the top surface of the RF tag 1 can function as a protective cover (top cover) that protects the inlay 10 arranged inside the tag from the external environment.
In addition, the second auxiliary antenna 30 placed over the inlay 10 inside the RF tag 1 can function as an antenna for the inlay 10 together with the first auxiliary antenna 20 . As a result, even when the inlay 10 is covered with the first/second auxiliary antennas 20 and 30, good wireless communication characteristics can be obtained without impairing the communication function.

In particular, by forming the first auxiliary antenna 20, which serves as the top cover (protective cover) of the RF tag 1, from a metal member (metal plate), it is possible to improve durability, impact resistance, pressure resistance, etc. against physical forces such as impacts and pressures applied to the RF tag 1 from the outside, and to effectively prevent failure, damage, etc., of the inlay 10 arranged inside due to external forces and impacts.
In addition, the first auxiliary antenna 20 functioning as a protective cover for the RF tag 1 is arranged so as not to overlap at least part of the inlay 10 and/or the second auxiliary antenna 30, and the second auxiliary antenna 30 is arranged so as not to overlap at least the IC chip 11 with respect to the inlay 10, so that the first/second auxiliary antennas 20 and 30 function as antennas for the inlay 10, and the communication characteristics of the RF tag 1 can be maintained and improved in a favorable state.

Therefore, even if the inlay 10 is partially or wholly covered with the first/second auxiliary antennas 20, 30, the electrical characteristics of the inlay 10 are not affected, and the antenna functions of the antenna section 12 of the inlay 10 and the first/second auxiliary antennas 20, 30 can be effectively utilized to maximize the antenna gain.
As described above, in the RF tag 1 according to the present embodiment, the antenna unit 12 and the loop circuit 11a provided in the RF tag 1 itself can function effectively and to the maximum, while the first/second auxiliary antennas 20 and 30 can be arbitrarily configured and arranged, the degree of freedom in designing the RF tag 1 can be improved, the first/second auxiliary antennas 20 and 30 can be adjusted and changed, etc., which are most suitable for the inlay 10 to be used, and a metal-compatible RF tag capable of obtaining good communication characteristics can be realized. be able to.

Although the preferred embodiments of the RF tag of the present invention have been described above, the RF tag according to the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the present invention.

For example, in the above-described embodiment, the articles and objects to which the RF tag according to the present invention is attached are assumed to be, for example, aluminum metal containers and metal housings.
That is, the RF tag according to the present invention can be applied to any article or object as long as the RF tag is used and predetermined information/data is read/written via a reader/writer. For example, in addition to aluminum metal containers and metal housings, metal heaters, electrical appliances, tableware, cooking utensils, furniture, fixtures, containers, automobiles, etc. Can be suitably used for any metal goods / objects.

INDUSTRIAL APPLICABILITY The present invention can be suitably used as an RF tag that is attached to any article or object, such as a cargo pallet or container, and that has a structure for protecting the inlay in order to increase durability and impact resistance.

1 RF tag 10 Inlay 11 IC chip 11a Loop circuit 12 Antenna section 13 Sealing film 20 First auxiliary antenna (protective cover)
30 Second Auxiliary Antenna 40 Dielectric Layer 50 Dielectric Layer 100 Back Metal Body (Mounting Object)
200 back non-metal body (mounting object)

Claims (7)

an inlay comprising at least an IC chip and a loop circuit electrically coupled to the IC chip;
a first auxiliary antenna arranged to overlap the IC chip and the loop circuit of the inlay;
a second auxiliary antenna arranged with respect to the inlay so as not to overlap at least the IC chip;
a dielectric layer arranged to overlap the inlay and the second auxiliary antenna;
with
The first auxiliary antenna is
arranged so as not to overlap at least a part of the inlay and/or the second auxiliary antenna on the surface of the dielectric layer opposite to the surface on which the inlay is arranged;
An RF tag, wherein the inlay, the first auxiliary antenna, and the second auxiliary antenna are electromagnetically coupled. A second dielectric layer is disposed on the surface of the inlay opposite to the surface on which the dielectric layer is disposed,
2. The RF tag according to claim 1, wherein the second dielectric layer, together with the dielectric layer, is formed into a case shape that covers the inlay and the second auxiliary antenna. The inlay is
comprising the IC chip, an antenna section including the loop circuit, and a substrate on which the IC chip and the antenna section are mounted,
The antenna section
3. The RF tag according to claim 1, wherein only the loop circuit is composed of either the loop circuit and a monopole antenna connected to the loop circuit, or the loop circuit and a dipole antenna connected to the loop circuit. 3. The RF tag according to claim 2, further comprising a back metal body arranged on the surface of the second dielectric layer opposite to the surface on which the first auxiliary antenna is arranged. The first auxiliary antenna is
The RF tag according to any one of claims 1 to 4, comprising a predetermined metal plate that functions as a protective member for the inlay. The RF tag according to any one of claims 1 to 5, wherein the length of the long side of the first auxiliary antenna is half the wavelength of the communication frequency of the inlay. The RF tag according to any one of claims 1 to 6, wherein the first auxiliary antenna and the second auxiliary antenna are not formed with cutouts.

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