WO2006059366A1 - Wireless tag device - Google Patents

Abstract

A wireless tag device includes an antenna, and a wireless tag chip for transmitting/receiving information through the antenna. The antenna is provided with a first antenna part coupled with the wireless tag chip, and a second antenna part electrostatically coupled with the first antenna part. One kind of the antennas of the wireless tag device is electrostatically coupled with other metal pattern and the metal pattern is permitted to function as an antenna. Thus, manufacturing cost of the wireless tag device is reduced and the reliability of the wireless tag device is improved.

Description

 Specification

 Wireless tag device

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a wireless tag device, and further to an improved technique for an antenna structure in the wireless tag device.

 Background art

 [0002] A tag information management device is known in which a wireless tag is attached to an article conveyed by a conveyance line, and information on the wireless tag is read or written by an antenna.

[0003] Technologies related to wireless tags include a technology that can secure an antenna necessary for signal transmission in a predetermined position for a long time (see Patent Document 1), and a technology for attaching a non-contact tag to a book 'magazine ( Patent document 2) is known.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-192114

 Patent Document 2: JP 2004-42340 A

 Disclosure of the invention

 Problems to be solved by the invention

 [0005] Patent Document 1 requires a precise alignment between a force chip and an antenna that can be used when a non-contact antenna using inductive coupling by a coil is used. In Patent Document 2, a tag label extension antenna is joined by ohmic connection using a conductive adhesive.

 [0006] Wireless tag devices are required to be smaller and less expensive in the factory. Costs cannot be reduced in assembly processes that require strict alignment. Conductive adhesives are also expensive and need to be manufactured under a controlled process in terms of contact reliability. Also, these all provide only a single antenna characteristic. As the use of wireless tag devices spreads, it is necessary to attach tags to objects of various forms and materials, and the directivity of communication according to the objects is required.

[0007] However, preparing a wireless tag device having an antenna corresponding to an individual application causes an increase in manufacturing cost. In addition, it is required to attach wireless tags to metal objects with complicated shapes. In general, metal reflects and shields radio waves, preventing its operation as a wireless tag. For this reason, wireless tags with standard antennas often hinder communication. Yes.

 An object of the present invention is to reduce the manufacturing cost of a wireless tag device.

Another object of the present invention is to improve the reliability of a wireless tag device.

[0010] The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

 Means for solving the problem

[0011] The outline of typical ones of the inventions disclosed in the present application will be briefly described as follows.

 [1] In a wireless tag device including an antenna and a wireless tag chip capable of exchanging information via the antenna, the antenna includes a first antenna unit coupled to the wireless tag chip, and And a second antenna portion electrostatically coupled to the first antenna portion. According to this, each type of RFID tag antenna is electrostatically coupled by bringing it into contact with another metal pattern without direct current conduction, thereby allowing the metal pattern to function as an antenna, thereby enabling individual applications. It is no longer necessary to prepare many types of wireless tags with antennas that meet the requirements. This achieves a reduction in the manufacturing cost of the wireless tag device. In addition, the additional antenna part (second antenna part) that is electrostatically coupled to the first antenna part is joined with an insulating adhesive and is not a metal-to-metal contact. Does not cause deterioration. This improves the reliability of the RFID tag device.

 [2] At this time, the antenna can have directivity by the shape of the second antenna portion.

 [3] The second antenna part can be a conductive pattern formed on a three-dimensional object, and the conductive pattern is electrostatically coupled to the first antenna part.

 [0015] [4] The second antenna portion may be a conductive pattern formed in a circular or spiral shape on a cylindrical object, and the conductive pattern is electrostatically coupled to the first antenna portion. Made up.

[5] The second antenna portion may be a conductive pattern formed in a cube in an L shape or U shape, and the conductive pattern is electrostatically applied to the first antenna portion. Combined Become.

 [6] The second antenna portion may be a structure having a metal force, and the structure is electrostatically coupled to the first antenna portion.

[7] At this time, the structure functions as a ground plane by being electrostatically coupled to the first antenna unit.

[8] The one antenna part may be a metal pattern coupled to an antenna terminal formed on the RFID tag chip by a bonding wire.

[9] The first antenna portion may be a capacitive coupling pattern formed on the RFID tag chip.

 [10] In a wireless tag device including an antenna and a wireless tag chip capable of exchanging information via the antenna, the antenna includes a first antenna unit coupled to the wireless tag chip, The first antenna portion can be formed with an electrostatic coupling surface that can function as an antenna by electrostatic coupling.

[0022] [11] In a wireless tag device including a wireless tag chip capable of exchanging information via an antenna, an electrostatic coupling surface is provided by which the metallic member can function as an antenna by being electrostatically coupled to the metallic member. be able to.

[12] At this time, the electrostatic coupling surface may be a metal pattern coupled to an antenna terminal formed on the RFID tag chip by a bonding wire.

[13] The electrostatic coupling surface may be a pattern for electrostatic coupling formed on the RFID tag chip.

 The invention's effect

 [0025] The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

That is, the manufacturing cost of the wireless tag device can be reduced. In addition, the reliability of the wireless tag device can be improved.

 Brief Description of Drawings

FIG. 1 is a plan view of a state where a small wireless tag included in a wireless tag device according to the present invention is attached to an additional antenna. FIG. 2 is a side view showing a state where a small wireless tag included in the wireless tag device according to the present invention is attached to an additional antenna.

 FIG. 3 is a plan view of the main part of the wireless tag device.

 FIG. 4 is a side view of the main part of the wireless tag device.

 FIG. 5 is a plan view of another configuration example of the wireless tag device.

 FIG. 6 is a plan view of another configuration example of the wireless tag device.

 FIG. 7 is a plan view of a wireless tag chip included in the wireless tag device.

 8 is a plan view of a wireless tag device including the wireless tag chip shown in FIG.

 FIG. 9 is a side view of a wireless tag device including the wireless tag chip shown in FIG.

 FIG. 10 is a side view showing another configuration example of the wireless tag chip.

 FIG. 11 is a plan view of another configuration example of the wireless tag device.

 12 is an enlarged side view of the main part of the wireless tag device shown in FIG.

 FIG. 13 is a perspective view of another configuration example of the wireless tag device.

 FIG. 14 is a perspective view of another configuration example of the wireless tag device.

 FIG. 15 is a perspective view of another configuration example of the wireless tag device.

 FIG. 16 is a perspective view of another configuration example of the wireless tag device.

 FIG. 17 is a perspective view of another configuration example of the wireless tag device.

 FIG. 18 is a cross-sectional view taken along line AA ′ in FIG.

 FIG. 19 is an enlarged cross-sectional view of the main part in FIG.

 FIG. 20 is a cross-sectional view of another configuration example of the wireless tag device.

 FIG. 21 is a block diagram showing an example of the overall configuration of the wireless tag device.

Explanation of symbols

 103, 201 RFID tag chip

 400 RFID tag device

 401 External antenna

 402 Power Department

 403 Signal section

404 road switch 405 Rectifier circuit

 406 voltage regulator

 407 Demodulation circuit

 408 Control circuit

 409 EEPROM

 410 Reader / Writer Equipment

 411 Antenna for reader / writer device

 BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 21 shows a configuration example of a wireless tag device that works on the present invention.

The wireless tag device 400 includes a wireless tag chip 103. An external antenna 401 is coupled to the RFID tag chip 103. As will be described in detail later, the external antenna 401 includes a first antenna unit coupled to the antenna terminal of the RFID tag chip 103 and an additional antenna unit (second antenna unit) electrostatically coupled to the first antenna unit. ). Although not particularly limited, the RFID tag device is attached to an article conveyed by a conveyance line, and RFID tag information can be exchanged with the reader / writer device 410 to which the reader / writer side antenna 411 is coupled. . Since known devices can be applied as they are to the reader / writer device 410 and the reader / writer side antenna 411, detailed descriptions thereof are omitted here.

[0031] The wireless tag chip 103 includes a power unit 402 that converts a 45 GHz band radio wave to a DC voltage provided from the reader / writer device 410, and a signal unit 403 that handles a signal to be transmitted and received, and a known semiconductor integrated circuit It is formed into one semiconductor substrate such as a silicon substrate by manufacturing technology.

[0032] The power unit 402 rectifies the 45-GHz band radio wave received by the external antenna 401 by the rectifier circuit 405, converts it to DC power, stabilizes it by the voltage regulator 406, and feeds it to the signal unit 403. The signal unit 403 includes a demodulation circuit 407 that demodulates a modulated radio wave signal from the reader / writer device 410, a control circuit 408 that controls the operation of each unit, and a 128-byte (Byte) that is a nonvolatile memory that stores data. ) EEPROM (Electrically Erasable Programmable Read-Only Memory) 409. The demodulator circuit 407 is a voltage rectified by the rectifier circuit 405. By detecting the pressure fluctuation, the signal sent from the reader / writer device 410 is demodulated. The control unit 408 controls reading and writing of the EEPROM 409, sending of a signal to the reader / writer device 410, and the like according to commands and data in the demodulated signal. Signal transmission to the reader / writer device 410 is performed by turning on and off the load switch 404. When the load switch 404 is turned on, the antenna terminals are short-circuited, and the reflected wave from the external antenna 401 of the RFID tag chip 103 to the antenna 411 of the reader / writer device 410 changes. The reader / writer device 410 detects the change in the reflected wave and reads the signal from the RFID tag chip 103. While the load switch 404 is on, the power unit 402 cannot generate power, but during this time, the signal unit 403 is operated with the power stored in the capacitor in the voltage regulator 406. The signal from the reader / writer device 410 to the RFID tag chip 103 is a manchester encoded signal, and is transmitted after on / off modulation of a 2.45 GHz radio wave. The transfer rate is 40kbps before encoding. A signal transmitted from the wireless tag chip 103 to the reader / writer device 410 is an encoded signal and is transmitted with the load switch 404 turned on and off. At this time, the reader / writer device 410 continues to send a radio wave of 2.45 GHz to supply power to the RFID tag chip 103, and at the same time, receives a modulation signal from the load switch 404.

 Hereinafter, the configuration of the wireless tag device 400 will be specifically described.

 FIG. 3 and FIG. 4 are a plan view and a side view of the main part of the wireless tag device 400.

The RFID tag chip 103 is mounted on metal patterns 107 and 108 formed on a polyimide sheet 113. The size of the semiconductor RFID tag chip 103 is 1.5 mm × l.5 mm. The small wireless tag 102 has a length Lc of 15 mm and a width W of 4.2 mm. The antenna terminals 109 and 110 of the small RFID tag chip 103 are connected to the metal patterns 107 and 108 by bonding wires 111 and 112, respectively. The metal patterns 107 and 108 function as an antenna of the wireless tag device 400, but because of the small size, the antenna efficiency is low and the communication distance is short. According to the inventor's experiment, the communication distance of a 300 mW reader / writer device with a 6 dBi circularly polarized antenna is about 20 mm. The small wireless tag 102 is supplied as a reel or a sheet with an adhesive on the back surface. And the user is that reel Alternatively, the small wireless tag 102 is peeled off from the sheet, and a desired additional antenna (second antenna part)

). Here, the metal patterns 107 and 108 correspond to the first antenna portion in the present invention.

FIG. 1 and FIG. 2 are a plan view and a side view of the state where the small wireless tag 102 shown in FIG. 3 and FIG. 4 is attached to the attached antenna.

The small wireless tag 102 is attached to the attached antenna 105. At this time, the metal patterns 107 and 108 in the small wireless tag 102 are electrostatically coupled to the power antenna 105. The attached antenna 105 is not particularly limited, but is formed by providing a metal pattern on the polyimide sheet 104.

 [0038] When the length Lc of the small wireless tag 102 is 15 mm and the width W is 4.2 mm, the antenna pattern length La of the attached antenna 105 is 55 mm. The thickness of the polyimide sheet 104 is 0.1 mm, and the thickness of the metal pattern on the polyimide sheet is 0.015 mm. The thickness of the adhesive for adhering the attached antenna 105 and the small wireless tag 102 is set to 20 / zm or less so that good electrostatic coupling is performed. In the electrostatic coupling unit 106, the antenna unit of the small wireless tag 102 and the auxiliary antenna 105 are electrostatically coupled, so that the auxiliary antenna 105 also functions as an antenna of the wireless tag device 400. At this time, the electrical characteristics, for example, the characteristic impedance of the antenna terminal of the RFID tag chip 103 are matched to the characteristic impedance of the antenna including the antenna portion of the small RFID tag 102 and the additional antenna 105 electrostatically coupled thereto. Thus, the efficiency of transmission / reception performed through the antenna portion of the small wireless tag 102 and the additional antenna 105 electrostatically coupled thereto is improved.

[0039] The attached antenna 105 functions as an antenna of the wireless tag device 400, so that communication can be performed in a wider range than the case of the small wireless tag 102 alone. According to the experiment of the present inventor, the communication distance of a 300 mW reader / writer device 410 with a 14 dBi circularly polarized antenna is about 600 mm.

[0040] Note that the small wireless tag 102 can be turned over so that the metal surface of the small wireless tag and the attached antenna 105 are brought close to each other for mounting. By reducing the thickness of the bonding adhesive, the electrostatic coupling impedance can be further reduced. In this case, the small wireless tag Even if the metal surface and the metal pattern 105 of the attached antenna 105 are in direct contact with each other, there is no problem in operation.

 FIG. 5 shows another configuration example of the wireless tag device.

 [0042] The small wireless tag 102 shown in FIG. 3 and FIG. 4 is adhered to the ends of the two metal patterns 131 printed on the paper 130 with an insulating adhesive. 7, 108 and the metal pattern 131 are electrostatically coupled. In such a configuration, it functions as a U-shaped antenna due to the effect of the additional antenna by the metal pattern 131. Due to the directivity of the U-shaped antenna in the direction of the opening, the communication distance in that direction is expanded compared to the small wireless tag 102 alone.

 FIG. 6 shows another configuration example of the wireless tag device.

 [0044] The small wireless tag 102 is bonded to two substantially L-shaped metal patterns 133 printed on the paper 132 with an insulating adhesive. Due to the effect of the attached antenna by the metal pattern 133, it functions as an antenna with a wide directivity, and the communication distance is expanded as compared with the small wireless tag 102 unit. Further, the overall length of the tag can be made shorter than that of the wireless tag having the attached antenna 105 shown in FIG.

 FIG. 7 shows a configuration example of the wireless tag chip.

 An antenna pattern having electrostatic coupling portions 202 and 203 is formed on the RFID tag chip 201, and this antenna pattern is connected to the antenna terminals 204 and 205 of the RFID tag chip 201. The chip size is 1.5mm X I. 5mm.

 An impedance matching pattern 206 is provided for impedance matching between the RFID tag chip 201 and the antenna. The RFID tag chip 201 having an on-chip antenna including the metal patterns 202, 203, and 206 that function as antennas is formed by a semiconductor process. Here, the metal patterns 202, 203, and 206 correspond to the first antenna in the present invention.

[0048] Since the antenna efficiency of the RFID tag chip 201 having an on-chip antenna is very low, it can communicate with a reader / writer device with a small antenna with high power density only at a distance of 1 mm or less. Since the RFID tag chip 201 having an on-chip antenna can be configured as an additional antenna by simply bringing it close to a metal pattern, the antenna pattern is connected. Communication is possible without wearing. At the time of inspection, this method can be used to communicate with the chip to inspect the chip alone.

 FIGS. 8 and 9 are a plan view and a side view of a wireless tag device including the wireless tag chip 201 shown in FIG.

 A wireless tag chip 201 shown in FIG. 7 is overlaid on a metal pattern 212 formed on a polyimide sheet 211 and adhered with an insulating adhesive. The RFID tag chip 201 having an on-chip antenna and the metal pattern 212 are electrostatically coupled by the electrostatic coupling unit 213, and the metal pattern functions as an additional antenna, and the communication distance can be increased. The adhesive has a thickness of 20 m or less, and a sufficient coupling capacity for communication can be obtained. Even if the RFID tag 201 and the metal pattern 212 are in contact with each other and are connected in direct current, there will be no problem in operation!

 [0051] In order to increase the communication distance, the antenna may be bonded to a conductive object by wire bonding, a conductive adhesive, or the like.

 FIG. 10 shows another configuration example of the wireless tag chip.

 [0053] The RFID tag chip 207 shown in FIG. 10 is greatly different from that shown in FIG. 7 in that metal patterns 208 and 209 are formed on the entire upper surface and lower surface of the tag chip 207. 208 and the metal pattern 209 on the lower surface are connected to the antenna terminals. Of the metal pattern 208 on the upper surface and the metal pattern 209 on the lower surface, one is the hot side and the other is the ground side. The chip size is 1.5mm X I. 5mm. By using a reader / writer antenna that sandwiches the chip from above and below, communication is possible even with a single chip.

 FIG. 11 shows another configuration example of the wireless tag device. FIG. 12 is an enlarged side view of the main part in FIG.

The antenna 241 and the antenna 242 are configured by a metal pattern 247 configured on a polyimide film 248. A hot-side antenna 241 and a ground-side antenna 242 are bonded to the RFID tag chip 207 shown in FIG. 10 with a non-conductive adhesive. The thickness of the adhesive is 20 m or less, and the electrostatic coupling capacity between the antenna and the metal pattern of the chip 207 is large. The antenna and the metal pattern of the chip are connected with a low impedance sufficient for communication. Metal pattern 208 or 209 of antenna and chip 207 are conductive It is not necessary to consider insulation that does not hinder operation even if touched.

 [0056] It is possible to attach an antenna without worrying about the front / back, left / right, and up / down orientation of the chip, and the assembly process can be simplified.

FIG. 13 shows another configuration example of the wireless tag device.

 [0058] A metal pattern 311 is printed on the side surface of the cylindrical paper box, and the small wireless tag 102 is attached to the metal pattern with double-sided tape. The metal pattern 311 and the antenna of the small radio tag 1-2 are electrostatically coupled, and the metal pattern 311 functions as an additional antenna. Since the additional antenna is provided in this manner, communication at a longer distance than the small wireless tag 102 alone is possible. The antenna has a wide spherical directivity that is similar to a general U-shaped antenna. The metal pattern can also be formed on a wrapping paper for wrapping paper boxes.

 FIG. 14 shows another configuration example of the wireless tag device.

 [0060] An L-shaped metal pattern 312 is three-dimensionally printed on a cubic paper box, and a small wireless tag 102 is attached to the metal pattern with double-sided tape. The metal pattern 312 and the antenna of the small wireless tag are electrostatically coupled, and communication over a longer distance is possible than the small wireless tag alone. The metal pattern can be formed on a wrapping paper or a resin film for wrapping a paper box.

 FIG. 15 shows another configuration example of the wireless tag device.

 [0062] A U-shaped metal pattern 313 is three-dimensionally printed on the side surface of the cubic paper box, and the small wireless tag 102 is attached to the metal pattern 313 with double-sided tape. The metal pattern 313 and the antenna of the small wireless tag are electrostatically coupled, and communication over a longer distance is possible than the small wireless tag alone. The antenna shown in Fig. 15 has a wide spherical directivity close to that of a general U-shaped antenna. The metal pattern can also be formed on a wrapping paper or a resin film for wrapping a paper box.

 FIG. 16 shows another configuration example of the wireless tag device.

[0064] A spiral metal pattern 314 is three-dimensionally printed on the side surface of the cylindrical paper box, and the small wireless tag 102 is attached to the metal pattern with double-sided tape. The metal pattern 314 and the antenna of the small RFID tag are electrostatically coupled, and the distance is longer than the small RFID tag alone Communication is possible. The metal pattern can be formed into a wrapping paper or a resin film for wrapping a paper box.

 FIG. 17 shows another configuration example of the wireless tag device. FIG. 18 shows a cross section taken along line AA ′ in FIG. FIG. 19 shows an enlarged main part in FIG.

 [0066] The metal case 305 and the lid 306 of the metal case 305 are electrically insulated by an insulating rubber seal 307.

 [0067] An L-shaped wireless tag 302 is adhered to the inside of the lid with a double-sided tape 308. The L-shaped wireless tag 302 is formed by bending the small wireless tag 102 shown in FIGS. 3 and 4, for example. The lid 307 is electrostatically coupled to the antenna of the wireless tag 302, and the lid 307 functions as an additional antenna. Originally, since metal does not transmit radio waves, communication is not possible when a wireless tag is placed inside a metal lid, but communication is possible because the lid (metal member) itself functions as an antenna.

 FIG. 20 shows another configuration example of the wireless tag device.

 A U-shaped wireless tag 303 shown in FIG. 15 is adhered to the surface of the metal plate 309 with a double-sided tape 308. The antenna on one side of the U-shaped wireless tag 303 and the metal plate 309 are electrostatically coupled to each other at the bonded part, and the entire metal plate 309 functions as a ground plane, giving the characteristics of the L-shaped antenna on the ground plane as a whole. be able to.

 [0070] According to the above example, the following operational effects can be obtained.

[0071] (1) Depending on the product and application to which the wireless tag is attached, it is necessary to have a communication distance and directivity suitable for each. However, the preparation of many types of wireless tags with antennas according to individual applications leads to increased manufacturing costs. On the other hand, according to the above example, the metal pattern is made to function as an antenna by electrostatically coupling the antenna of one type of RFID tag device to the other metal pattern without bringing it into direct current conduction. Thus, the directivity and reading distance of the wireless tag can be changed simply by bringing an additional pattern close to the existing standard wireless tag by tape bonding or pressing. If the target object to which the tag is attached is a metal, the target object itself can be used as an antenna. In addition, the RFID tag antenna is electrostatically coupled to a metal object, so that the metal tag can be used as an antenna element or ground plane to communicate with the RFID tag. Can be increased. In a further development, an antenna including an electrostatic coupling pattern formed on-chip is formed. On-chip antennas have a very small communicable distance, but tags that can be communicated over long distances can be formed simply by attaching additional antennas close to each other by tape, etc., which greatly reduces tag assembly costs. . Thereby, the manufacturing cost of the wireless tag device can be reduced. In addition, the initial data can be written on-chip. In addition, inspection and writing of initial data can be performed only by bringing the attached antenna close.

 [0072] (2) The physical basis of an additional antenna that can function other metal patterns as an antenna is as follows.

[0073] Strictly speaking, the force that needs to handle the phase of the electromagnetic wave is described for simplicity, and only the scalar quantity of the impedance is described. Also, the relationship between the structure and the capacitance is simplified to an infinite parallel plate. Replacing the pattern overlap with a simple model that looks like a parallel plate, the capacitance c of the parallel plate is c = ε OX ε τ Χ (S / t), and the impedance of electrostatic coupling | Z | is | Z | 1 Z (j ω c) = 1Z (j2 π fc). Here, ε 0 is the dielectric constant of vacuum, ε r is the relative dielectric constant, S is the area of the overlapping portion of the parallel plates, t is the interval between the parallel plates, j is the imaginary unit, and ω is the angular frequency of the radio wave. Note that ω = 2 π ί and f is the frequency of radio waves. The polyimide on the antenna substrate of the small wireless tag has a relative dielectric constant of 3.3 and a thickness of 0.1 mm. For example, when 25 square millimeter (5 mm square) patterns overlap, the capacitance is 7.3 pF and the impedance is 8.7 ohms. This impedance is sufficiently lower than the input impedance of the RFID tag chip. There is no big difference in antenna efficiency from connecting an antenna with conductivity! In addition, if the interval is increased by attaching double-sided tape, etc., the area to be overlapped should be widened. For small on-chip antennas where power cannot be obtained, it is sufficient to reduce the overlap. Capacitive coupling is possible. Also, if the reader / writer is moved closer to the RFID tag antenna and the power density is increased, communication is possible even if there is a lot of loss with a small electrostatic coupling capacity. With the attached antenna attached, It does not necessarily need to be closely matched to the input impedance of the chip antenna terminal. The design of the actual additional antenna pattern is performed by the electromagnetic simulator by inputting the 3D shape including the electrostatic coupling with the additional antenna. Anne required by simulator The antenna performance is designed so that the antenna terminal impedance of the RFID tag chip and the antenna impedance connection loss are as small as possible. However, strict impedance matching is not required unless a large communication distance is required. If the communication distance is actually lZio, the power that can be received by the tag is proportional to the square of the communication distance, so the coupling efficiency between the antenna and the chip may be 1Z100. 2. The advantage of 45GHz band wireless tags is that the tag antenna can be downsized and smaller tags can be realized compared to 13.5MHz and 900MHz band wireless tags. The tag is small and requires an appropriate shape and directivity depending on the object to be mounted. However, it is costly to prepare a wireless tag with an individually designed antenna for these requirements. Therefore, if the communication distance and directivity can be changed by simply attaching an additional pattern to the antenna with a basic pattern with a short communication distance by bonding or the like, it is possible to meet the requirements of the object at low cost. By realizing the same thing with an on-chip antenna, conventional assembly work such as wire bonding can be eliminated. 2. The reason why sufficient electrostatic coupling can be obtained only by the proximity of the pattern with a 45 GHz wireless tag is because the impedance is sufficiently low even with a small capacitance because of the high frequency. As a physical phenomenon, 2.45 GHz band high frequency characteristics are effectively used. For this reason, it can be used simply by bringing a metal pattern that does not take electrical conductivity by double-sided tape connection, general adhesive, or the like. The attached antenna can be bent into any shape that is very thin, such as an aluminum-deposited laminated film. Also, it can be created at a very low cost by printing or the like. In addition, if the object to be attached with the tag is a metal, the object can be used as an antenna element or a ground plane by electrostatically coupling the antenna of the small tag to the metal, so that the communication distance can be increased. it can.

 [0074] (3) The secondary antenna portion (second antenna portion) electrostatically coupled to the first antenna portion is joined with an insulating adhesive, and is not a contact between metals. Therefore, characteristic deterioration due to poor contact does not occur. Thereby, the reliability can be improved.

[0075] While the invention made by the present inventors has been specifically described based on the embodiments, it goes without saying that the present invention is not limited thereto and can be variously modified without departing from the gist thereof. . Industrial applicability

 The present invention can be widely applied to a wireless tag device that enables exchange of information through an antenna.

Claims

The scope of the claims  [1] A wireless tag device including an antenna and a wireless tag chip capable of exchanging information via the antenna,  The antenna includes a first antenna unit coupled to the RFID tag chip and a second antenna unit electrostatically coupled to the first antenna unit.  [2] The radio tag device according to claim 1, wherein the antenna has directivity by the shape of the second antenna portion.  [3] The wireless tag device according to claim 1, wherein the second antenna unit is a conductive pattern formed on a three-dimensional object, and the conductive pattern is electrostatically coupled to the first antenna unit. .  [4] The second antenna portion is a conductive pattern formed in a circular arc or a spiral shape on a cylindrical object, and the conductive pattern is electrostatically coupled to the first antenna portion. The wireless tag device according to 1. 5. The second antenna portion is a conductive pattern formed in an L shape or U shape in a cube, and the conductive pattern is electrostatically coupled to the first antenna portion. Wireless tag device.  6. The wireless tag device according to claim 1, wherein the second antenna part is a structure made of metal, and the structure is electrostatically coupled to the first antenna part. 7. The wireless tag device according to claim 6, wherein the structure functions as a ground plane by being electrostatically coupled to the first antenna unit. 8. The wireless tag device according to claim 1, wherein the one antenna portion is a metal pattern coupled to an antenna terminal formed on the wireless tag chip by a bonding wire. 9. The wireless tag device according to claim 1, wherein the first antenna portion is an electrostatic coupling pattern formed on the wireless tag chip. [10] A wireless tag device including an antenna and a wireless tag chip that enables exchange of information via the antenna, The antenna includes a first antenna unit coupled to the RFID tag chip, The first antenna unit is a wireless tag device having an electrostatic coupling surface that can function as an antenna by electrostatic coupling.  [11] A wireless tag device including a wireless tag chip capable of exchanging information via an antenna,  A wireless tag device having an electrostatic coupling surface capable of functioning as an antenna by electrostatic coupling to a metal member.  12. The RFID tag device according to claim 11, wherein the electrostatic coupling surface is a metal pattern coupled to an antenna terminal formed on the RFID tag chip by a bonding wire.  13. The wireless tag device according to claim 11, wherein the electrostatic coupling surface is an electrostatic coupling pattern formed on the wireless tag chip.