JP4169059B2 - Radio tag and article with radio tag attached - Google Patents

Description

The present invention is used by attaching to an article, information capable of wireless communication radio tag associated with the object, an article wireless tag is attached.

A conventional wireless tag is used by being attached to an article, and has an integrated circuit for storing information and an antenna for wireless communication, and reads information from the integrated circuit without contact or updates information on the integrated circuit. It is configured to be able to. For this reason, when a wireless tag is used, production management in a manufacturing process, product management in physical distribution, and the like can be performed. Here, some articles to which the wireless tag is attached, such as those containing metal or moisture, affect the radio waves.
It is known to use a microstrip antenna (also called a patch antenna) with directivity on one side so that the antenna of the wireless tag is not affected by the article when the wireless tag is attached to a metal or the like. Yes. However, in the case of a microstrip antenna, it may be difficult to receive radio waves if the direction of the antenna on the reader / writer side does not match the direction of the microstrip antenna of the wireless tag. For this reason, in the conventional microstrip antenna, two antennas having the same radiation pattern are bonded to each other with ground conductors, and reception data is obtained by calculating a logical sum of outputs from the two antennas. Yes (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 5-80148

By the way, when performing communication, it is necessary to match not only the antenna direction but also the characteristics of the reader / writer antenna and the characteristics of the microstrip antenna of the wireless tag. In general, antenna characteristics include polarization characteristics and frequency characteristics. These characteristics are specific to the shape of the antenna, and stable communication can be continued in the conventional configuration. It was difficult.
The present invention has been made in view of such circumstances, and a main object of the present invention is to make it easy to match the characteristics of an antenna to a reader / writer.

The invention according to claim 1 of the present invention for solving the above-mentioned problems is characterized in that a first electrode having a pair of first sides that are formed in a substantially rectangular planar shape and contribute to transmission and reception of radio waves, and the first electrode A pair of second electrodes that are provided on one surface of the dielectric and on the other surface opposite to the one surface of the dielectric and that are formed in a substantially rectangular planar shape and contribute to transmission and reception of radio waves An integrated circuit that is disposed at a position offset from the center of each of the first electrode and the second electrode and is electrically connected to each of the two electrodes; have a, the first electrode and the second electrode was set to the wireless tag, characterized in that there is a capable of transmitting and receiving circularly polarized waves different from each other.
This wireless tag can have different antenna characteristics when transmitting and receiving radio waves using the first electrode and antenna characteristics when transmitting and receiving radio waves using the second electrode. In particular, this wireless tag can have different polarization characteristics when transmitting and receiving radio waves using the first electrode and polarization characteristics when transmitting and receiving radio waves using the second electrode.

According to a second aspect of the present invention, in the wireless tag according to the first aspect, the first electrode and the second electrode can transmit and receive radio waves having different frequencies .

According to a third aspect of the present invention for solving the above-mentioned problems , a first electrode having a pair of first sides which are formed in a substantially rectangular plane shape and contribute to transmission / reception of radio waves, A pair of electrodes that are provided on one surface of the dielectric and the other surface on the opposite side of the one surface of the dielectric and that are formed in a substantially rectangular planar shape and contribute to transmission and reception of radio waves A second electrode having a second side; and an integrated circuit disposed at a position offset from the center of each of the first electrode and the second electrode and electrically connected to each of the two electrodes The wireless tag is characterized in that the first electrode and the second electrode can transmit and receive radio waves having different frequencies.
These wireless tags can have different antenna characteristics when transmitting and receiving radio waves using the first electrode and antenna characteristics when transmitting and receiving radio waves using the second electrode. In particular, these wireless tags can have different frequency characteristics when transmitting and receiving radio waves using the first electrode and frequency characteristics when transmitting and receiving radio waves using the second electrode.

According to a fourth aspect of the present invention, in the wireless tag according to the second or third aspect , the first electrode is capable of transmitting and receiving a 2.5 GHz band radio wave, and the second electrode is a 950 MHz band radio wave. Can be transmitted and received .
This wireless tag can transmit and receive radio waves in the 2.5 GHz band when the first electrode is used. When the second electrode is used, radio waves in the 950 MHz band can be transmitted and received. It is possible to switch and use when the communication environment is different.

According to a fifth aspect of the present invention, in the wireless tag according to the first or second aspect, an inclined portion in which the first electrode is cut corresponding to the right-handed circularly polarized wave is a diagonal line of the first electrode. It has a pair on the top, and the second electrode has a pair of inclined portions cut corresponding to the left-handed circularly polarized wave on the diagonal line of the second electrode.
The invention according to claim 6 is the wireless tag according to any one of claims 2 to 4, wherein the first side and the second side are arranged in parallel to each other. In addition, the length dimension is different from each other.

Invention, a wireless tag according to any one of claims 1 to 6, and the conductor in which the first electrode or the second electrode of the wireless tag is attached detachably in accordance with claim 7 The conductor is an article to which a wireless tag is attached, characterized in that it is 1/10 or more longer than the effective wavelength of the radio wave for communication from each of the first side and the second side. .
The article to which the wireless tag is attached can wirelessly communicate even if the wireless tag is difficult to communicate by itself using the conductor portion of the article. The antenna characteristics change between the case where the first electrode side is disposed close to the conductor and the case where the second electrode side is disposed close to the conductor.

  According to the present invention, the antenna characteristics can be changed between the case where the first electrode is selected for wireless communication and the case where the second electrode is selected for wireless communication. For this reason, information management can be reliably performed even when the communication environment is different.

The best mode for carrying out the invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the wireless tag 1 includes an antenna laminate 5 in which a first electrode 3 and a second electrode 4 are provided so as to sandwich a rectangular substrate 2 made of a dielectric, and an antenna. And an integrated circuit 6 disposed on the first electrode 3 side of the laminate 5 for use. Such a wireless tag 1 is sometimes called an RFID (Radio Frequency Identification) tag or an IC (Integrated Circuit) tag.

  The first electrode 3 is made of a substantially rectangular and planar conductor attached to one surface 2A of the substrate 2. An integrated circuit 6 is attached at a position that is offset from the center by a predetermined distance on an axis C1 parallel to the side of the first electrode 3 through the center of the first electrode 3. A through hole 7 is formed in the substrate 2 in accordance with the arrangement position of the integrated circuit 6. The through hole 7 penetrates from one surface 2A on which the first electrode 3 is formed to the other surface 2B on the opposite side, and the inside is a conductor layer. Around the through hole 7 is a removal portion 8 from which the first electrode 3 has been removed, so that the first electrode 3 and the second electrode 4 do not directly conduct. The second electrode 4 is connected to the integrated circuit 6 through the through hole 7. The first electrode 3 is also connected to the integrated circuit 6. That is, the wireless tag 1 has a connection point 9A, 9b (power supply position of the integrated circuit 6) with respect to the first electrode 3 and the second electrode 4 at a position offset from the center of the first electrode 3 and the axis C1. Is set on.

  In the first electrode 3, a pair of sides parallel to the axis C1 is an open end 31 that contributes to transmission / reception of radio waves. A part of the open end 31 is cut obliquely. The inclined portion 31A formed by cutting is a portion corresponding to two corners on a diagonal line. By adopting such a shape (radiation pattern), the first electrode 3 can oscillate or receive a right-handed circularly polarized wave. The length La of the first electrode 3 in the direction of the axis C1 is ¼ of the effective wavelength λ of radio waves for communication. The length Lb of the pair of sides 32 orthogonal to the axis C <b> 1 is substantially the same as the open end 31.

  The substrate 2 is manufactured from a dielectric such as glass epoxy or ceramics. The outer shape of the substrate 2 in plan view is substantially equal to the outer shape (= La × Lb) of the first electrode 3.

  As shown in FIG. 3, the second electrode 4 covers substantially the entire other surface 2 </ b> B of the substrate 2. A pair of sides parallel to the axis C1 in the second electrode 4 is an open end 41 that contributes to transmission / reception of radio waves. A part of the open end 41 is cut obliquely. The inclined portion 41 </ b> A formed by the cutting is a corner that is symmetric with the first electrode 3. For this reason, the second electrode 4 appears to substantially overlap the first electrode 3 in plan view. The shape (radiation pattern) of the second electrode 4 is suitable for oscillating or receiving a left-handed circularly polarized wave. The length La of the second electrode 4 in the direction of the axis C1 is ¼ of the effective wavelength λ of radio waves for communication. The length in the direction orthogonal to the axis C <b> 2 is substantially equal to the length of the substrate 2.

  In the wireless tag 1, since the sizes of the first and second electrodes 3 and 4 are substantially equal, when the antenna laminate 5 is used as a single antenna, the conventional ground conductor side is larger than λ / 10. Gain is smaller than the antenna.

  Here, the reader / writer 51 of the wireless tag 1 is shown in FIG. The reader / writer 51 includes an antenna laminate 52 for communicating with the wireless tag 1 and a main body 53 to which the antenna laminate 52 is connected. The main body 53 is modulated by a memory 55 that holds data, a control unit 56 having a CPU (Central Processing Unit), a modulation unit 57 that modulates data generated by the control unit 56 into a signal suitable for wireless communication, and the like. A transmission amplifier 58 that amplifies the signal and emits it from the antenna laminate 52, a reception amplifier 59 that amplifies the radio signal received by the antenna laminate 52, and a controller 56 that demodulates data from the amplified radio signal And a demodulator 60 that passes the data to the receiver. Note that the antenna laminate 52 uses a microstrip antenna or loop antenna that outputs one of right-handed circularly polarized wave and left-handed circularly polarized wave at a wavelength λ.

FIG. 5 shows how the wireless tag 1 is used. The wireless tag 1 is used by being attached to a conductor 62 included in an article 61 to be managed. The second electrode 4 is fixed to the conductor 62 via the adhesive layer 65. As the adhesive layer 65, an adhesive or a double-sided tape is used, and has a strength that allows the wireless tag 1 to be removed from the article 61 as necessary. If it is not necessary to collect the wireless tag 1, an adhesive layer 65 that cannot be removed may be formed.
The adhesive layer 65 is preferably thin, but may have a thickness of about 5 mm or may be thinner. The thickness of the conductor 62 is arbitrary, and the length Ld in the direction orthogonal to the axis C1 of the wireless tag 1 is larger by λ / 10 on one side than the pair of open ends 31 of the first electrode 3. The conductor 62 may be the whole or a part of the component 61 of the article 61, or a metal sheet attached to the article 61. The article 61 to be affixed with the wireless tag 1 is a metal can in which beverages or processed products are housed, or a container for packing the contents with paper or plastic. For example, the conductor 62 may be partially attached.

Next, the operation of this embodiment will be described.
First, when the wireless tag 1 is manufactured, the through holes 7 are formed by a drill or the like on a copper-clad laminate in which a copper foil is affixed to both surfaces 2A and 2B of the substrate 2 made of a dielectric. The through hole 7 is electrolessly plated and then copper plated to form a conductor layer in the through hole 7. Thereafter, the pattern of the first electrode 3 and the pattern of the removal portion 8 are patterned on one surface 2A by a known mask exposure technique, and the excess copper foil is chemically etched. As a result, the connection point 9A of the first electrode 3, the connection point 9B around the through hole 7, and the cut portion are formed. The integrated circuit 6 is joined to the connection points 9A and 9B by soldering or the like.

  In this wireless tag 1, the first electrode 3 and the second electrode 4 are approximately equal in size, so that the radio wave is not only in the direction indicated by the arrow Y1 in FIG. Oscillation also occurs slightly in the direction indicated by the arrow Y2, which is the stacking direction of the electrodes 4. As a result, the directivity of the antenna laminate 5 is low with the wireless tag 1 alone, and the radio wave intensity necessary for wireless communication cannot be obtained. Therefore, practical communication, that is, reading / writing of information cannot be performed with the reader / writer 51 even at a distance where wireless communication can be performed with a conventional wireless tag.

On the other hand, as shown in FIG. 5, when the wireless tag 1 is attached to the article 61 with the second electrode 4, the conductor 62 cooperates with the second electrode 4 and functions as a ground conductor. It has radiation characteristics having single-side directivity as indicated by arrow Y3. In addition, communication using antenna characteristics defined by the shape of the first electrode 3, that is, a right-handed circularly polarized wave is possible. As described above, since the right-handed circularly polarized wave transmission characteristics and reception characteristics sufficient for wireless communication can be obtained, the information stored in the integrated circuit 6 is read by the reader / writer 51 in the same manner as the conventional wireless tag. Or the information of the reader / writer 51 can be stored in the integrated circuit 6.
On the other hand, as shown in FIG. 6, when the wireless tag 1 is attached to the article 61 with the first electrode 3 , the conductor 62 cooperates with the first electrode 3 and functions as a ground conductor. It comes to have radiation characteristics with single-side directivity as shown. In addition, communication using antenna characteristics defined by the shape of the second electrode 4, that is, a left-handed circularly polarized wave is possible. As described above, since the left-handed circularly polarized wave transmission characteristic and reception characteristic sufficient for wireless communication can be obtained, wireless communication can be performed in the same manner as a conventional wireless tag.

When the wireless tag 1 becomes unnecessary, the wireless tag 1 is peeled off from the article 61. In a state where the article 61 is away from the conductor 62, that is, in the state shown in FIG. 4, the wireless tag 1 becomes incapable of communication again, so that information on the wireless tag 1 cannot be read. For example, when the article 61 is a can containing beverages, product information, production management, and distribution information are managed by the wireless tag 1 at the manufacturing and distribution stages, and the wireless tag 1 is peeled off when the can is sold to a customer. For example, it is possible to prevent product information, production management, and logistics information from leaking to third parties.
Note that when the wireless tag 1 is attached to the conductor again, wireless communication becomes possible, so that the wireless tag 1 can be reused. The conductor at this time may be the conductor 62 of the article 61 or another conductor.

  Next, another usage pattern and communication system of the wireless tag will be described with reference to FIG. An object (article) to which the wireless tag 1 is attached is a non-contact type IC card 81 such as a personal authentication card. The card body 82 of the IC card 81 is manufactured from an insulating material, and a fixing portion 83 to which the second electrode 4 of the wireless tag 1 is attached is recessed. The fixed portion 83 is larger than the length Lb between the open ends 31 of the first electrode 3 by λ / 10 or more on both sides. Furthermore, the thickness of the fixing | fixed part 83 is 0-5 mm. For the adhesive layer to which the second electrode 4 is attached, it is preferable to use a layer from which the wireless tag 1 cannot be removed. When the card body 82 is thin, the fixing portion 83 may not be formed in a concave shape. Further, the wireless tag 1 may be sandwiched between the card body 82, and the dielectric 21 of the wireless tag 1 may be a card substrate. Furthermore, a conductor may be used for a part of the card body 82 (a part away from the fixing part 83).

Since the wireless tag 1 has no difference in size between the first and second electrodes 3 and 4, the gain of the antenna laminate 5 is low, and when the IC card 81 is handled alone, communication is performed with the conventional wireless tag. Even with a possible distance, practical communication with the reader / writer 51 cannot be performed. Therefore, when communicating with the IC card 81, the communication system 85 is used. The communication system 85 includes a reader / writer 51 and a conductor 86 disposed within the communicable range of the reader / writer 51. The conductor 86 is large enough to place the IC card 81 and is sufficiently larger than the wireless tag 1. When the IC card 81 is placed on the conductor 86 with the second electrode 4 side of the wireless tag 1 facing toward the conductor 86, the wireless tag 1 and the conductor 86 cooperate to increase the gain of the antenna laminate 5, and the right indicated by the arrow Y3. Wireless communication using circularly polarized radio waves becomes possible.
On the other hand, when the IC card 81 is turned over and the front surface 82A is placed on the conductor 86 and the back surface 82B is directed to the reader / writer 51, the first electrode 3 is disposed close to the conductor 86. As a result, an antenna characteristic determined by the second electrode 4 is obtained, and wireless communication using a left-handed circularly polarized radio wave indicated by an arrow Y4 becomes possible.

In this way, when the IC card 81 is stored or carried, if one of the electrodes 3 and 4 is kept away from the conductor, the information on the wireless tag 1 can be read by an external reader / writer or the information can be read. It becomes impossible to write. Therefore, it is possible to prevent information from being skimmed or tampered with in a situation not intended by the owner. Specifically, practical communication cannot be performed not only when the IC card 81 is stored in a bag but also when it is in a wallet or a pocket.
In addition, when it is necessary to read and write information, wireless communication can be performed simply by placing it on a conductor 86 such as a metal plate, so that communication control can be easily performed. Therefore, security can be improved when the wireless tag 1 is used. In addition, a communication obstruction member that absorbs radio waves is provided separately, and measures such as covering the wireless tag 1 with the communication obstruction member other than during use are unnecessary.

According to the present embodiment, the electrodes 3 and 4 having shapes corresponding to different circularly polarized waves are arranged on the both surfaces as the radiation surface of the antenna, and the other electrode is brought close to the other conductor, thereby making one electrode Since the antenna characteristics matched to the shape can be obtained, it is possible to cope with different circularly polarized waves and to perform wireless communication more reliably.
Since the sizes of the two electrodes 3 and 4 and the substrate 2 in a plan view are substantially equal, the wireless tag 1 can be made smaller than in the conventional case where the ground conductor side is larger than λ / 4 with respect to the radiation electrode. Can be
Since the antenna laminate 5 has a shape that makes it difficult to perform wireless communication by itself, information is not skimmed or altered when handled by the wireless tag 1 alone, and security can be improved.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment. Moreover, the description which overlaps with 1st Embodiment is abbreviate | omitted.
As shown in FIGS. 8 and 9, in the wireless tag 91, a first electrode 93 is provided on one surface 92A of a rectangular substrate 92 made of a dielectric, and a second electrode 94 is provided on the other surface 92B. The antenna laminate 95 and the integrated circuit 6 arranged on the first electrode 93 side are provided.

The first electrode 93 has a length Lf of a pair of open ends 101 parallel to an axis C1 passing through the center and the connection points 9A and 9B of the integrated circuit 6 having a first frequency (eg, 2.45 GHz band). It is approximately equal to ¼ of the wavelength λ1.
The second electrode 94 has a pair of sides 102 parallel to the axis C1 passing through the center of the second electrode 94 and the through-hole 7. The length of the second electrode 94 is equal to the length Le of the substrate 2. It is approximately equal to / 4.

The wireless tag 91 is used by being attached to a conductor 62 of an article 61 as illustrated in FIG. The length Ld of the conductor 62 is larger than λ / 10 from the open end 101 (the antenna laminate 95) to the periphery of the conductor 62 when the wireless tag 91 is attached. When the wireless tag 91 is fixed to the conductor 62 on the second electrode 94 side, the second electrode 94 and the conductor 62 serve as a ground pattern, and antenna characteristics using the first electrode 93 as a radiation electrode are exhibited. As a result, wireless communication is possible using radio waves of the first frequency.
On the other hand, as shown in FIG. 11, when the wireless tag 91 is attached to the conductor 62 on the first electrode 93 side, the first electrode 93 and the conductor 62 become a ground pattern and the second electrode 94 is attached. The antenna characteristic as a radiation electrode appears. As a result, wireless communication is possible using radio waves of the second frequency.

  Further, when the IC card 81 is used as an IC card 81 such as a personal authentication card as illustrated in FIG. 7, the antenna laminate 95 does not function as an antenna, so that communication is performed even when the reader / writer 51 is brought close. It is not possible. When the IC card 81 is disposed on the conductor 86 as in the communication system 85, the antenna laminate 95 and the conductor 86 cooperate to become a practical antenna, and communication can be performed. In this case, when the IC card 81 is placed in a direction in which the conductor 86 and the second electrode 94 are close to each other, antenna characteristics using the first electrode 93 as a radiation electrode can be obtained and communication can be performed at the first frequency. On the other hand, when the IC card 81 is placed in the direction in which the first electrode 93 is close to the conductor 86, antenna characteristics using the second electrode 94 as a radiation electrode can be obtained and communication can be performed at the second frequency. .

According to this embodiment, the electrodes 93 and 94 corresponding to different frequency bands are arranged on both sides as the radiation surface of the antenna, and the other electrode is brought close to the other conductor to match the shape of one electrode. Therefore, it is possible to cope with two different frequency bands, and wireless communication can be performed more reliably. As an example of use of such a wireless tag, there is a form in which the frequency band used in the process of distribution is different (when the country or region is different in the middle of distribution).
When the difference in size between the two electrodes 93 and 94 is small, the wireless tag can be miniaturized and the security can be enhanced as in the first embodiment.
When the size of the second electrode 94 is larger than λ / 4 in the direction perpendicular to the axis compared to the size of the first electrode 93, the wireless tag 91 alone is used for the first electrode 93. Can be used.

(Third embodiment)
A third embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component as each said embodiment. Further, the description overlapping with the above-described embodiments is omitted.
As shown in FIGS. 12 and 13, in the wireless tag 111, a first electrode 113 is provided on one surface 92A of a rectangular substrate 92 made of a dielectric, and a second electrode 114 is provided on the other surface 92B. And the integrated circuit 6 disposed on the first electrode 113 side.

In the first electrode 113, the length Lf of a pair of sides 121 parallel to the axis C1 passing through the center and the connection points 9A and 9B of the integrated circuit 6 has a wavelength of a first frequency (for example, 2.45 GHz band). A pair of inclined portions 121A that are substantially equal to ¼ of λ1 and cut in accordance with the right-handed circularly polarized wave are diagonally provided.
The length of the pair of sides 122 parallel to the axis C1 passing through the center and the through hole 7 of the second electrode 114 is substantially equal to ¼ of the wavelength λ2 of the second frequency (for example, 950 MHz band), A pair of inclined portions 122A cut in correspondence with the left-handed circularly polarized wave is provided at diagonal positions.
The outer shape of the substrate 92 is adjusted to the size of the second electrode 114 and is larger than the first electrode 113.

  This wireless tag 111 selectively uses communication using a right-handed circularly polarized wave of the first frequency and communication using a left-handed circularly polarized wave of the second frequency, depending on the direction of attachment to the conductor. be able to. For this reason, communication corresponding to two different frequencies can be more reliably performed. The combination of the frequency and the direction of the circular polarization may be reversed, or may be a shape that is a right-hand circular polarization or a left-hand circular polarization.

  Note that the present invention can be widely applied without being limited to the above-described embodiment. The manufacturing method of the wireless tags 1, 91, 111 and the material to be used are not limited to the embodiment. Further, the article to which the wireless tags 1, 91, 111 are attached may be an article used for another shape or application.

It is a top view which shows the structure of the wireless tag which concerns on embodiment of this invention. It is a side view of the wireless tag shown in FIG. It is a bottom view of the wireless tag shown in FIG. FIG. 4 is a diagram illustrating a configuration of a reader / writer and explaining that the reader / writer cannot communicate with a single wireless tag. It is a figure explaining an example of the articles | goods which attach a radio | wireless tag, and the radio | wireless tag attached to the articles | goods can transmit / receive right-handed circularly polarized wave. It is a figure explaining an example of the articles | goods which attach a radio | wireless tag, and the radio | wireless tag attached to the articles | goods can transmit / receive left-handed circularly polarized wave. It is a figure explaining an example of an IC card to which a wireless tag is attached, explaining that communication with a reader / writer is possible only when the IC card is placed on a plate, and that polarization characteristics can be changed depending on the orientation of the card. . It is a top view which shows the structure of the wireless tag from which the size of a 1st electrode and a 2nd electrode differs. FIG. 9 is a side view of the wireless tag illustrated in FIG. 8. It is a figure explaining while showing an example of the goods which attach a wireless tag, and the wireless tag attached to the goods can transmit and receive the electromagnetic wave of the 1st frequency. FIG. 5 is a diagram illustrating an example of an article to which a wireless tag is attached and explaining that the wireless tag attached to the article can transmit and receive radio waves of a second frequency. It is a top view which shows the structure of the radio | wireless tag from which a frequency characteristic and a polarization characteristic differ by a 1st electrode and a 2nd electrode. FIG. 13 is a bottom view of the wireless tag illustrated in FIG. 12.

Explanation of symbols

1, 91, 111 RFID tag 2, 92 Substrate 3, 93, 113 First electrode 4, 94, 114 Second electrode 6 Integrated circuit 31, 41, 121, 122 Open end 31A, 41A, 121A, 122A Inclined portion 61 Article 62, 86 Conductor 81 IC card 83 Fixed part C1 Axis

Claims (7)

A first electrode having a pair of first sides formed in a substantially rectangular planar shape and contributing to transmission and reception of radio waves ;
A dielectric provided with the first electrode on one surface;
A second electrode provided on the other surface opposite to the one surface of the dielectric and having a pair of second sides formed in a substantially rectangular planar shape and contributing to transmission and reception of radio waves ;
Wherein is arranged at a position offset from the respective centers of the first electrode and the second electrode, have a, an integrated circuit electrically connected to each of the two electrodes,
The wireless tag, wherein the first electrode and the second electrode are capable of transmitting and receiving mutually different circularly polarized waves . The wireless tag according to claim 1, wherein the first electrode and the second electrode can transmit and receive radio waves having different frequencies . A first electrode having a first side of the pair contribute to transmission and reception of radio waves is formed in a substantially rectangular planar shape,
A dielectric provided with the first electrode on one surface;
A second electrode provided on the other surface opposite to the one surface of the dielectric and having a pair of second sides formed in a substantially rectangular planar shape and contributing to transmission and reception of radio waves ;
Wherein is arranged at a position offset from the respective centers of the first electrode and the second electrode, have a, an integrated circuit electrically connected to each of the two electrodes,
The wireless tag, wherein the first electrode and the second electrode can transmit and receive radio waves having different frequencies . Said first electrode is configured to be transmitted and received radio waves 2.5GHz band radio of claim 2 or claim 3 wherein the second electrode is characterized in that it is a capable of transmitting and receiving radio waves of 950MHz band tag. The first electrode has a pair of inclined portions cut corresponding to right-handed circularly polarized waves on the diagonal of the first electrode, and
3. The wireless tag according to claim 1, wherein the second electrode has a pair of inclined portions that are cut in correspondence with the left-handed circularly polarized wave on a diagonal line of the second electrode. 5. The first side and the second side are arranged in parallel to each other and have different lengths from each other. 6. Wireless tag. And the wireless tag according to any one of claims 1 to 6, wherein and a conductor in which the first electrode or the second electrode of the wireless tag is attached detachably, said conductor, An article to which a wireless tag is attached, characterized in that each of the first side and the second side is 1/10 or more longer than the effective wavelength of a radio wave for communication.

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