JP2007124638A - Sheet body, antenna device, and electronic information transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a transmission environment in communicating using an antenna element of electromagnetic field near a conductive member. <P>SOLUTION: A sheet body 10 has a shield layer 13. The shield layer 13 can recover an input impedance of the electromagnetic field type antenna effectively and can operate the electromagnetic field type antenna near the conductive member, by using this between the antenna element and the conductive member or near the antenna element since the shield layer 13 is a material with a magnetism. Further, it becomes possible to suppress a loss of electromagnetic energy and increase the radiation efficiency in case of operating the electromagnetic field type antenna near the conductive member, by making a real part number μ' of a complex relative permeability of the shield layer 13 high and making a permeability loss term tanδμ small. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet body for wireless communication using an electric field type antenna element in the vicinity of a member having a portion made of a conductive material, and an electronic information transmission apparatus including the sheet body.

  In the present invention, the electric field type antenna element has a function of an electric field type antenna element used for radio communication of a radio system, and has a function of a magnetic field type antenna element or a magnetic field type. The antenna element may be switched.

  FIG. 19 is a simplified cross-sectional view of a conventional tag 1. An RFID (Radio Frequency IDentification) system is a system used for automatic recognition of a solid, and basically includes a reader and a transponder. A tag 1 is used as a transponder of this RFID system. The tag 1 includes a coiled loop antenna 2 that is a magnetic field type antenna that detects magnetic field lines, and an integrated circuit (IC) 3 that performs wireless communication using the antenna 2. The tag 1 is configured so as to transmit information stored in the IC 3 upon receiving a request signal from the reader, in other words, the information held in the tag 1 can be read by the reader. Is done. The tag 1 is attached to a product, for example, and is used for product management, such as prevention of product theft and grasping inventory status.

  When the tag 1 is used by being attached to a metal product and there is a member 4 having a portion made of a conductive material in the vicinity of the antenna 2, the magnetic field generated by the electromagnetic wave signal transmitted and received by the antenna 2 is generated. The magnetic field lines flow along the surface of the portion of the member 4 made of the conductive material. In this case, an eddy current is induced in the portion of the member 4 made of a conductive material, and electromagnetic wave energy is converted into heat energy and lost due to the eddy current loss. When energy is lost in this manner, the electromagnetic wave signal is greatly attenuated, and the tag 1 cannot wirelessly communicate. In addition, the induced eddy current generates a magnetic field opposite to the communication magnetic field of the tag, thereby causing a phenomenon that the magnetic field is canceled. This phenomenon also prevents the tag 1 from performing wireless communication. Therefore, the tag 1 cannot be used in the vicinity of the member 4 having a portion made of a conductive material. In addition, the resonance frequency of the tag 1 shifts due to the influence of the member 4, and there is a phenomenon that communication at the original communication frequency becomes impossible, so that wireless communication of the tag 1 becomes difficult.

  FIG. 20 is a simplified cross-sectional view showing a tag 1A, which is another conventional technique. A tag 1A shown in FIG. 20 is similar to the tag 1 of FIG. 19, and the same reference numerals are given to corresponding portions, and only different configurations will be described. In order to solve the problem of the tag 1 in FIG. 19, the tag 1 </ b> A in FIG. 20 includes a magnetic absorption plate 7 provided so as to be disposed between the member 4 that is an article to be attached and the antenna 2. Configured as follows. The magnetic absorption plate 7 which is a sheet having a complex relative permeability is made of a high permeability material such as sendust, ferrite and carbonyl iron, and thus a material having a high complex relative permeability.

  The complex relative permeability has a real part and an imaginary part, and the complex relative permeability increases as the real part increases. In other words, a material having a high complex relative permeability has a high real part in the complex relative permeability. When a material having a high real part in the complex relative permeability exists in the magnetic field, the magnetic field lines are concentrated in the member. In the tag 1A using the magnetic field type antenna 2 for detecting the magnetic field lines, the magnetic absorption plate 7 is provided to prevent the magnetic field from leaking to the member 4 having the portion made of the conductive material, and has the portion made of the conductive material. Even when used in the vicinity of the member 4, wireless communication can be performed by reducing the lines of magnetic force passing through the member 4 having a portion made of a conductive material and suppressing the attenuation of magnetic field energy. Such a tag 1A is disclosed in, for example, Patent Document 1.

  As described above, the sheet having the complex relative permeability that has been studied as a metal-compatible technology for antenna communication is mainly for improving self-inductance. The effect of improving the communication environment by this sheet is an effect obtained when a coil antenna, which is a magnetic field type antenna when performing electromagnetic induction type communication, is used.

JP 2000-113142 A

  When a magnetic field type antenna 2 such as a coil antenna in the case of electromagnetic induction communication is used like the tag 1A shown in FIG. 20, the member 4 having a portion made of a conductive material by preventing leakage of the magnetic field. However, such a configuration for preventing magnetic field leakage is considered ineffective when using an electric field type antenna that detects electric lines of force. The adoption was not considered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet body capable of suitably performing wireless communication in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element, an antenna device including the sheet body, and electronic information transmission Is to provide a device.

  In the present invention, when wireless communication is performed in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element, between the antenna element and a member having a portion made of a conductive material or in the vicinity of the antenna element The sheet body is characterized in that a reduction in input impedance of the antenna element due to a member having a portion made of a conductive material is suppressed.

  According to the present invention, the sheet member is provided between the electric field type antenna element and the member having a portion made of a conductive material or in the vicinity of the antenna element, so that the antenna element has a portion having a portion made of a conductive material. When arranged in the vicinity, a decrease in input impedance of the antenna element due to a member having a portion made of a conductive material can be suppressed.

  If the sheet body is not used, the electric field type antenna element hardly operates in the vicinity of a member having a portion made of a conductive material and cannot be used for wireless communication. This is because the input impedance of the electric field type antenna element is significantly reduced. The decrease in input impedance is caused by a phenomenon in which the antenna element and a member having a portion made of a conductive material are short-circuited at a high frequency. This phenomenon is not via eddy currents and is unique to electric field antennas.

  When the input impedance of the electric field type antenna element becomes small, the impedance of the communication means that communicates using the electric field type antenna element deviates, and a signal can be passed between the electric field type antenna element and the communication means. It will disappear. The sheet body can suppress a decrease in input impedance of the antenna element when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material. Therefore, by using the sheet body, radio communication can be suitably performed even in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element.

  In the present invention, when wireless communication is performed in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element, the antenna element and the member having a portion made of a conductive material are connected or in the vicinity of the antenna element. The sheet body is characterized in that loss of electromagnetic energy caused by a member having a portion made of a conductive material is suppressed.

  According to the present invention, the sheet member is provided between the electric field type antenna element and the member having a portion made of a conductive material or in the vicinity of the antenna element, so that the antenna element has a portion having a portion made of a conductive material. When arranged in the vicinity, loss of electromagnetic energy due to a member having a portion made of a conductive material can be suppressed. If the sheet body is not used, the electric field type antenna element hardly operates in the vicinity of a member having a portion made of a conductive material and cannot be used for wireless communication. This reason is explained because electromagnetic energy is consumed because electromagnetic coupling occurs in a member having a portion made of an antenna element and a conductive material even in an electric field type antenna element. In a member having a portion made of a conductive material, a current that is not an eddy current is induced by a high-frequency short circuit, and a change to thermal energy due to resistance loss when this current occurs, and a reverse magnetic field generated by the current The electromagnetic energy is lost by canceling the magnetic field of the electromagnetic wave for communication. As a countermeasure, the sheet body can suppress the loss of electromagnetic energy when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material. The reason for this is that the short-circuit is less likely to occur, and the vicinity of the electric field type antenna element, which is a conductor part where current is generated, and a member having a part made of a conductive material (that is, the inside of the sheet body). This is because the loss of electromagnetic energy can be prevented by concentrating the magnetic field distribution in () and allowing the magnetic field to pass through without being attenuated. The above-described impedance adjustment (matching) also plays an important role in preventing electromagnetic energy loss. Therefore, by using the sheet body, wireless communication can be suitably performed in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element.

  According to the present invention, the antenna element includes at least one of a dipole antenna, a monopole antenna, a loop antenna, or an antenna loaded with a reactance structure portion thereon.

  According to the present invention, by using the sheet member, for example, a dipole antenna having a simple configuration can be used for wireless communication in the vicinity of a member having a portion made of a conductive material. First, the antenna element can be miniaturized by combining a dipole antenna and a sheet. This is coupled with the height of the real part μ ′ of the complex relative permeability and the real part ε ′ of the complex relative permittivity of this sheet body, which adds a wavelength shortening effect and achieves a much smaller size than the conventional product. It is because it can do. The dipole antenna is linear and may be curved or bent and may have a free shape. For example, there is a horseshoe shape. It is sufficient if the total length is λ / 2. For example, at 950 MHz, the length is about 15.8 cm, but the effect of shortening the wavelength by this sheet body is added to this, so that a linear element of about 3 to 10 cm becomes possible, and further bending is applied to a label of 2 to 3 cm. The size that fits is possible. Furthermore, it can also be reduced in size and the object which can be pasted will spread over a wide range. Since the monopole antenna feeds power between the element on one side of the dipole antenna and the ground plate, the total length of the element can be further reduced to λ / 4. In the case of a loop antenna, when the entire circumference is close to one wavelength, it can be approximated to a structure in which two half-wave dipole antennas are arranged, and can be regarded as an electric field type antenna element. These antennas can also preferably perform wireless communication in the vicinity of the communication disturbing member. Further, these antenna elements may or may not be loaded with a resonance matching portion (reactance matching portion) by an inductance (L) component and a capacitor (C) component.

  Further, the invention is characterized in that the frequency of the electromagnetic wave used for wireless communication is included in a range of 300 MHz to 300 GHz.

  According to the present invention, a relatively long-range wireless communication distance can be realized with a small antenna by using an electromagnetic wave included in a frequency range of 300 MHz to 300 GHz. The range of 300 MHz to 300 GHz includes the UHF band (300 MHz to 3 GHz), the SHF band (3 GHz to 30 GHz), and the EHF band (30 GHz to 300 GHz).

  According to the present invention, the frequency of the electromagnetic wave used for wireless communication is included in the range of 860 MHz to 1 GHz.

  According to the present invention, since the frequency of the electromagnetic wave used for wireless communication is a frequency included in the range of 860 MHz to 1 GHz, it can be applied to communication between relatively distant devices. Furthermore, the wavelength of electromagnetic waves used for wireless communication is relatively small, and communication can be performed using a small electric field type antenna.

  Further, the invention is characterized in that the frequency of electromagnetic waves used for wireless communication is included in the 2.4 GHz band.

  According to the present invention, since the frequency of the electromagnetic wave used for wireless communication is a frequency included in the 2.4 GHz band, it can be applied to communication between relatively distant devices. Furthermore, the wavelength of electromagnetic waves used for wireless communication is relatively small, and communication can be performed using a small electric field type antenna.

Further, the present invention is a sheet body including a shield layer that is a magnetic body.
According to the present invention, the sheet member used between the antenna element and the member having a portion made of a conductive material or in the vicinity of the antenna element includes a shield layer that is a magnetic substance. The shield layer, which is a magnetic material, is effective for suppressing a decrease in impedance caused by a member having a portion made of a conductive material that exists in the vicinity of an electric field type antenna element. A current is induced by a high-frequency short circuit in a member having a portion made of a conductive material in the vicinity of the antenna element, and a decrease in impedance is observed. However, even in an electric field type antenna, a shield layer including a magnetic substance The presence can suppress the impedance reduction. This impedance adjustment corresponds to only a specific frequency when the magnetic properties of the magnetic material have frequency dependence.

  In addition, the present invention is characterized by including a shield layer in which the real part μ ′ of the complex relative permeability is equal to or higher than the imaginary part μ ″ of the complex relative permeability at the frequency of the electromagnetic wave used for wireless communication.

  According to the present invention, the sheet body is provided with a shield layer, and the shield layer has a real part μ ′ of complex relative permeability at an electromagnetic wave frequency used for wireless communication and an imaginary part μ of complex relative permeability. “More than that, therefore μ ′ ≧ μ”. As a result, the real part μ ′ of the complex relative permeability indicating the ease of collecting the magnetic field is larger than the imaginary part μ ″ of the complex relative permeability that thermally converts (losses) the magnetic field and has a portion made of a conductive material. It is possible to realize a sheet body that can suppress a decrease in input impedance of the antenna element due to the member and more efficiently suppress a loss of electromagnetic energy due to the member having a portion made of a conductive material. Further, the real part μ ′ of the complex relative permeability of the shield layer has an effect of shortening the wavelength of the antenna element together with the real part ε ′ of the complex relative permittivity, and contributes to the miniaturization of the antenna element.

  In the present invention, the real part μ ′ of the complex relative permeability is 5 or more and the permeability loss term tan δμ (= μ ″ / μ ′) is 1 or less at the frequency of the electromagnetic wave used for wireless communication. A shield layer is provided.

  According to the present invention, the sheet body is provided with a shield layer, and the shield layer has a real part μ ′ of the complex relative permeability of 5 or more and a permeability loss at the frequency of the electromagnetic wave used for wireless communication. The term tan δμ is 1 or less. As a result, when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material, a decrease in input impedance of the antenna element due to the member having a portion made of a conductive material can be suppressed, and A sheet body that can suppress loss of electromagnetic energy due to a member having a portion made of a material can be realized.

  The present invention also includes a shield layer in which the real part μ ′ of the complex relative permeability is 20 or more and the permeability loss term tan δμ is 0.5 or less at the frequency of the electromagnetic wave used for wireless communication. And

  According to the present invention, the sheet body is provided with a shield layer, and the shield layer has a real part μ ′ of the complex relative permeability of 20 or more and a permeability loss at the frequency of the electromagnetic wave used for wireless communication. The term tan δμ is 0.5 or less. As a result, when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material, a decrease in input impedance of the antenna element due to the member having a portion made of a conductive material can be suppressed, and A sheet body that can suppress loss of electromagnetic energy due to a member having a portion made of a material can be realized.

  In addition, the present invention is characterized by including a shield layer having a real part ε ′ of a complex relative dielectric constant of 20 or more at the frequency of an electromagnetic wave used for wireless communication.

  According to the present invention, the sheet body is provided with a shield layer, and the shield layer has a real part ε ′ of a complex relative dielectric constant of 20 or more at the frequency of electromagnetic waves used for wireless communication. As a result, when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material, a decrease in input impedance of the antenna element due to the member having a portion made of a conductive material can be suppressed, and A sheet body that can suppress loss of electromagnetic energy due to a member having a portion made of a material can be realized. Further, the antenna can be downsized due to the wavelength shortening effect.

  In addition, the present invention is characterized by including a shield layer having an imaginary part ε ″ of a complex relative dielectric constant of 300 or less at the frequency of an electromagnetic wave used for wireless communication.

  According to the present invention, the sheet body is provided with a shield layer, and the shield layer has an imaginary part ε ″ of a complex relative dielectric constant of 300 or less at the frequency of electromagnetic waves used for wireless communication. When the element is disposed in the vicinity of a member having a portion made of a conductive material, a decrease in input impedance of the antenna element due to the member having a portion made of a conductive material can be suppressed, and the element is made of a conductive material. A sheet body capable of suppressing loss of electromagnetic energy due to a member having a portion can be realized.

Moreover, this invention is provided with the conductor layer which has electroconductivity.
According to the present invention, since the sheet body has a conductor layer, a shield is formed in accordance with the frequency of the electromagnetic wave used for the above-described wireless communication in a state where the conductor layer made of a conductive material exists in the vicinity of the antenna element. The real part μ ′ and the imaginary part μ ″ of the complex relative permeability of the layer or the real part ε ′ of the complex relative permittivity are adjusted, so that the preferable characteristics of the shield layer can be realized. More suitable wireless communication can be realized in the vicinity of the member having the portion.

  According to the present invention, the shield layer is a magnetic material made of at least one of soft magnetic metal, soft magnetic metal oxide, magnetic metal and magnetic metal oxide, or a material containing the same. Features.

  According to the present invention, the shield layer is a material made of at least one of soft magnetic metal, soft magnetic metal oxide, magnetic metal and magnetic metal oxide, or a material containing it. Therefore, the shield layer is formed using only these materials, or is realized by dispersing these materials in the binder. With this configuration, it is possible to form a shield layer that can obtain the aforementioned characteristics. Therefore, the sheet | seat body which achieves the above-mentioned outstanding effect is realizable.

  Further, the shield layer of the present invention comprises 1 part by weight or more and 1500 parts by weight or less of one or more materials selected from the group of ferrite, iron alloy and iron particles as a magnetic material with respect to 100 parts by weight of the organic polymer. It is characterized by comprising a material contained in a blended amount.

  According to the present invention, the shield layer is obtained by blending a magnetic material with an organic polymer serving as a binder. By using such a blend, stable magnetic properties can be obtained, and processability such as cutting and flexibility can be imparted.

Further, the present invention is characterized in that flame retardancy is imparted.
According to the present invention, the sheet body is flame retardant. For example, an electronic information transmission apparatus that performs wireless communication using an antenna element including a tag, a reader, and a mobile phone may be required to be flame retardant. The sheet body can be suitably used for applications that require such flame retardancy.

Further, the present invention is characterized in that thermal conductivity is imparted.
According to the present invention, the environment in which the sheet body is used may be used in the vicinity of a means serving as a heat source, such as a communication means including an IC and a power supply means. The excellent thermal conductivity of the sheet allows the heat generated by the heat source means to escape, suppresses the temperature rise of the heat source means, and reduces performance due to exposure to high temperatures. Can be prevented.

  Further, the present invention is characterized in that at least one surface portion has tackiness or adhesiveness.

  According to the present invention, since at least one surface portion is sticky or adhesive, it can be attached to another article such as a member having a portion made of the conductive material. Accordingly, the sheet body can be easily used.

According to another aspect of the present invention, there is provided an electric field type antenna element having a resonance frequency matched to a frequency used for wireless communication,
An antenna device comprising the sheet body.

  According to the present invention, the sheet body is provided between the antenna element and a member having a portion made of a conductive material or in the vicinity of the antenna element. As a result, the antenna device can be provided in the vicinity of a member having a portion made of a conductive material, and can be used for suitably communicating wirelessly and transmitting electronic information using the antenna element. Thus, an antenna device that can be suitably used in the vicinity of a member having a portion made of a conductive material can be realized.

The present invention is also an electronic information transmission device comprising the antenna device.
According to the present invention, it is possible to realize an electronic information transmission device capable of suitably performing wireless communication using an antenna device including an antenna element even when provided near a member having a portion made of a conductive material.

  The present invention is also characterized in that it is used as a transponder that is attached to a densely packed article.

  According to the present invention, an electronic information transmission device including a sheet body is used as a transponder of a radio frequency identification (RFID) system such as a tag, for example. However, the electromagnetic coupling with other transponders existing in the vicinity and the influence of other transponders can be suppressed. When multiple transponders are used in a dense state, the other transponders become members having a portion made of a conductive material and are affected by wireless communication. However, by providing a sheet body in the transponder, the influence of other transponders And the reading rate by the reader can be improved.

  According to the present invention, by providing the sheet member, it is possible to suppress a decrease in input impedance of the antenna element when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material. Therefore, by using the sheet body, radio communication can be suitably performed even in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element.

  Further, according to the present invention, by providing the sheet body, it is possible to suppress the loss of electromagnetic energy when the antenna element is disposed in the vicinity of a member having a portion made of a conductive material. Therefore, by using the sheet body, wireless communication can be suitably performed in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element.

  Further, according to the present invention, by using a sheet body, at least one of a dipole antenna, a monopole antenna, a loop antenna, or an antenna loaded with a reactance structure portion on a simple and small configuration is made of a conductive material. Wireless communication can be performed using in the vicinity of a member having a portion.

  Further, according to the present invention, wireless communication can be suitably performed using an electromagnetic wave having a frequency of 300 MHz to 300 GHz in the vicinity of a member having a portion made of a conductive material. Since electromagnetic waves of such a frequency are used, a relatively long wireless communication distance can be realized with a small antenna.

  Further, according to the present invention, the frequency of the electromagnetic wave used for wireless communication is a frequency included in the range of 860 MHz to 1 GHz, so that it can be applied to communication between relatively distant devices, and is an electric field type small size. It is possible to enable communication using the antenna.

  Further, according to the present invention, since the frequency of the electromagnetic wave used for wireless communication is a frequency included in the 2.4 GHz band, it can be applied to communication between relatively distant devices and is an electric field type small size. It is possible to enable communication using the antenna.

  In addition, according to the present invention, by using a shield layer that is a magnetic material, even in an electric field antenna, the impedance reduction can be controlled, and wireless communication is performed in the vicinity of a member having a portion made of a conductive material. be able to.

  Further, according to the present invention, since the real part μ ′ of the complex relative permeability of the shield layer is equal to or larger than the imaginary part μ ″ of the complex relative permeability, the reduction of the input impedance of the antenna element and the loss of electromagnetic energy are suppressed. The sheet | seat body which can do is realizable.

  According to the present invention, since the real part μ ′ of the complex relative permeability of the shield layer is 5 or more and the permeability loss term tan δμ is 1 or less, the input impedance of the antenna element is reduced, and the electromagnetic energy loss is reduced. The sheet | seat body which can suppress can be implement | achieved.

  According to the present invention, since the real part μ ′ of the complex relative permeability of the shield layer is 20 or more and the permeability loss term tan δμ is 0.5 or less, the input impedance of the antenna element is reduced, and the electromagnetic energy The sheet | seat body which can suppress the loss of is realizable.

  Further, according to the present invention, since the real part ε ′ of the complex relative permittivity of the shield layer is 20 or more, a sheet body that can suppress a decrease in input impedance of the antenna element and a loss of electromagnetic energy is realized. be able to.

  Further, according to the present invention, since the imaginary part ε ″ of the complex relative permittivity of the shield layer is 300 or less, a sheet body that can suppress a decrease in input impedance of the antenna element and a loss of electromagnetic energy is realized. be able to.

  Further, according to the present invention, the real part μ ′ and the imaginary part μ ″ of the complex relative permeability of the shield layer or the real part ε ′ of the complex relative permittivity is adjusted in the state where the conductor layer exists in the vicinity of the antenna element. Therefore, it is possible to realize a preferable characteristic of the shield layer, and thus it is possible to realize a more preferable wireless communication in the vicinity of a member having a portion made of a conductive material.

  Further, according to the present invention, the material is composed of at least one of a soft magnetic metal, a soft magnetic metal oxide, a magnetic metal, and a magnetic metal oxide, or is a material containing the material, and has the above-described characteristics. Can be formed. Therefore, the sheet | seat body which achieves the above-mentioned outstanding effect is realizable.

  According to the invention, the blending amount of 1 to 1500 parts by weight of one or more materials selected from the group of ferrite, iron alloy and iron particles as a magnetic material with respect to 100 parts by weight of the organic polymer. The shield layer is formed. Therefore, the sheet | seat body which achieves the above-mentioned outstanding effect is realizable.

  Moreover, according to this invention, the flame retardance of a sheet | seat body is obtained and it can use suitably also for the use for which a flame retardance is requested | required.

  Further, according to the present invention, when used in the vicinity of the means serving as the heat source, the heat generated by the means serving as the heat source can be released, and the temperature rise of the means serving as the heat source can be suppressed to increase the temperature. Performance degradation due to exposure can be prevented.

  Moreover, according to the present invention, at least one surface portion has adhesiveness or adhesiveness, and therefore can be attached to another article. Accordingly, the sheet body can be easily used.

  Further, according to the present invention, it is possible to realize an antenna device that is provided in the vicinity of a member provided with a sheet body and having a portion made of a conductive material and can be suitably used for wireless communication.

  Further, according to the present invention, it is possible to realize an electronic information transmission apparatus capable of suitably performing wireless communication even when provided in the vicinity of a member having a portion made of a conductive material.

  Further, according to the present invention, even when a transponder is attached to an article in a dense state, the electromagnetic coupling with other transponders and the influence of other transponders can be suppressed, and the reading rate by the reader can be improved. it can.

  FIG. 1 is a cross-sectional view schematically showing a sheet body 10 according to an embodiment of the present invention. The sheet body 10 is provided between the electric field type antenna element 11 and a member 12 having a portion made of a conductive material (hereinafter referred to as “communication disturbing member”) or in the vicinity of the antenna element, and communicates using the antenna element 11. In the wireless communication in the vicinity of the obstruction member 12, the sheet body 10 prevents the communication environment by the antenna element 11 from being deteriorated by the communication obstruction member 12. Here, the vicinity means a close position that affects the communication environment of wireless communication by the antenna element.

  The deterioration of the communication environment includes a decrease in input impedance of the antenna element 11 and a loss of electromagnetic energy. Further, the resonance frequency of the antenna element 11 may shift due to the influence of the communication disturbing member 12. Therefore, the sheet body 10 is a sheet body 10 that suppresses a decrease in input impedance of the antenna element 11 due to the communication disturbing member 12 and suppresses a loss of electromagnetic energy due to the communication disturbing member 12. Further, the resonance frequency may be adjusted by the sheet body 10, or may be further matched by a matching circuit (reactance loading portion).

  The antenna element 11 is not particularly limited as long as it is an electric field type antenna element. In the present embodiment, the antenna element 11 is a dipole antenna, a monopole antenna, or a loop antenna. In the case of a loop antenna, an electric field type behavior is exhibited when the peripheral length approaches one wavelength or approaches one wavelength. Here, one wavelength or a half wavelength of a dipole antenna or a quarter wavelength of a monopole antenna has an effective meaning. For example, the length corresponding to the wavelength is obtained by receiving a wavelength shortening effect by a dielectric constant or a magnetic permeability. Including the case where it comes.

  The electric field type antenna element referred to in the present invention refers to the function of the electric field type antenna element, that is, the electric lines of force, except for the function of the electromagnetic induction type magnetic field type antenna element, that is, only the function of detecting the lines of magnetic force. What has the function to detect may be used. Therefore, in an electric field type antenna element, an element that uses only the function of detecting electric lines of force, an element that uses both a function of detecting electric lines of force and a function of detecting lines of magnetic force, and a function of detecting electric lines of force And an element that switches and uses the function of detecting the lines of magnetic force alternately.

The conductive material as a communication disturbing member in the present invention is a material including only a material having conductivity and a material including a material having conductivity. This conductive material includes, for example, conductive materials such as metals, Si-based materials, graphite sheets, oxides such as ITO and ZnO, liquids such as water, chemicals, and oils, water-containing materials, etc. A material having a level of conductivity that can cause short circuits, coupling or interference at high frequencies. The conductive material is a material having conductivity, such as a metal such as a metal having a resistivity of 10 ⁻⁶ Ωcm or more and less than 10 ⁻¹ Ωcm, a liquid having a relatively low resistivity, water and seawater, and a semiconductor, And a relatively high resistivity material having a resistivity of 10 ^-1 Ωcm or more and 10 ⁶ Ωcm or less.

  The member having a portion made of a conductive material includes a member made of at least a part of a conductive material, the member made entirely of a conductive material, and the member made of only a part of a conductive material. Therefore, this member is a member having at least a part of conductivity, for example, only the surface portion may have conductivity, or the whole may have conductivity. Specifically, Includes other antenna bodies, other antenna elements, metal plates, metal containers, housings, shielding materials, conductive fibers, containers containing liquids, test tubes containing liquids, containers containing pastes, etc. .

  The antenna element 11 and the sheet body 10 may be attached via an adhesive layer or directly provided without an adhesive layer. The adhesive layer is sticky or adhesive, and is a layer made of a bonding agent. The antenna element 11 and the sheet body 10 are attached to each other by the stickiness or adhesiveness. The bonding agent is generally a dielectric, and the adhesive layer is also a dielectric layer. The structure provided directly may be a structure in which at least one of the antenna element 11 and the shield layer 13 is adhered to each other by the adhesiveness or adhesiveness, or the antenna element 11 is printed on the shield layer 13. The shield layer 13 may be applied, welded, fixed, embedded, sandwiched, or sprayed to the antenna element 11 or a support that supports the antenna element 11. For example, the configuration may be added. The support is, for example, a PET film.

  The sheet body 10 is a sheet body having an effect of shielding an electromagnetic field, and is an sheet body having an effect of shielding an electromagnetic field formed by an electromagnetic wave used for wireless communication. That is, it is a sheet for making it difficult for the electromagnetic field from the antenna element 11 to reach the communication disturbing member 12 in order to suppress the influence of impedance reduction or the like due to the communication disturbing member 12 in the vicinity of the antenna element 11. Although it is expressed as shielding here, it includes a case where a part is not completely shielded and a case where a magnetic field is concentrated and passed. Accordingly, the sheet body 10 is configured to block electromagnetic waves used for wireless communication, thereby suppressing the above-described deterioration of the communication environment.

  The electromagnetic wave to be blocked may be an electromagnetic wave used for any purpose, and the frequency of the electromagnetic wave to be blocked is determined by the use of the electromagnetic wave. The electromagnetic wave to be blocked is an electromagnetic wave used in, for example, an RFID system, and is an electromagnetic wave having a frequency included in a range of 860 MHz to 1 GHz (hereinafter referred to as “high MHz band”) belonging to the UHF band. Specifically, it is an electromagnetic wave having a frequency included in the range of 950 MHz to 956 MHz in Japan.

  The frequency of the electromagnetic wave to be blocked is an exemplification, and a configuration for blocking electromagnetic waves having a frequency other than the illustrated frequency is also included in the present invention. The material characteristics of the shield layer change with little difference in these frequency ranges, and the numerical values in the present invention can be used as they are.

  In addition, electromagnetic waves having a frequency in the 2.4 GHz band may be targeted for blocking. The 2.4 GHz band is a frequency range of 2400 MHz or more and less than 2500 MHz. The frequency of electromagnetic waves used in the RFID system is included in the range of 2400 MHz to 2483.5 MHz.

  The frequency of the electromagnetic wave to be blocked is not particularly limited, but any single frequency or a plurality of frequencies can be selected including a range of 300 MHz to 300 GHz. The range of 300 MHz to 300 GHz includes UHF band (300 MHz to 3 GHz), SHF band (3 GHz to 30 GHz), and EHF band (30 GHz to 300 GHz).

  The sheet body 10 is configured as a laminated body in which the shield layer 13, the conductor layer 14, and the adhesive agent layer 15 are laminated. The shield layer 13 is a layer for blocking an electromagnetic field, and is a layer for blocking electromagnetic waves.

  The conductor layer 14 is a layer made of a conductive material, and is made of copper in the present embodiment. Since the conductor layer 14 may affect the antenna element 11 as a communication disturbing member, the influence is suppressed by the shield layer 13. The conductor layer 14 may also function as an intermediate antenna. In order to improve the impedance of the conductor layer 14, slits can be inserted or divided, and the conductivity can be distributed. The size of the conductor layer 14 is not limited.

  The sticking agent layer 15 is a layer made of a sticking agent for sticking the sheet body 10 including the shield layer 13 to an article. The sticking agent includes at least one of a pressure-sensitive adhesive and an adhesive, and has a bonding force due to stickiness or adhesiveness.

  The shield layer 13, the conductor layer 14, and the sticking agent layer 15 are laminated in this order from one side in the thickness direction to the other side. A binder layer 16 made of an adhesive or an adhesive is interposed between the shield layer 13 and the conductor layer 14 or in the vicinity of the antenna element, and the shield layer 13 and the conductor layer 14 are coupled to each other by the binder layer 16. Has been. The adhesive layer 15 is bonded to the conductor layer 14 with its own adhesive force or adhesive force. Hereinafter, when the shield layer 13, the conductor layer 14, the adhesive layer 15, and the binder layer 16 are collectively referred to as the constituent layers 13 to 16.

  The conductor layer 14 and the adhesive agent layer 15 are not necessarily required constituent materials, and the shield layer 13 is attached to the communication blocking member 12 via the binding layer 16 or directly laminated without using the binding layer 16. It is also possible to do. Each of the constituent layers 13 to 16 of the sheet body 10 may be multi-layered. For example, the shield layer 13 may be multi-layered to give the magnetic permeability a gradient, or even a single layer to give the magnetic permeability a gradient. Can be used.

Although the thickness dimension of each layer 13-16 and the thickness dimension of the whole sheet | seat body 10 are not specifically limited, For example, in this Embodiment, the thickness dimension of the shield layer 13 is 1 micrometer or more and 10 mm or less. The thickness dimension of the conductor layer 14 is 100 mm (1 × 10 ⁻⁸ m) or more and 500 μm or less, the adhesive layer 15 is 1 μm or more and 1 mm or less, and the binder layer 16 is 1 μm or more and 1 mm or less. The overall thickness dimension of the sheet body 10 is 3 μm or more and 12 mm or less. The sheet body 10 can be reduced in overall thickness, and each of the layers 13 to 16 is made of the material as described above and has flexibility. Therefore, the sheet body 10 can be freely deformed.

  The shield layer 13 blocks electromagnetic waves used for wireless communication by selecting material characteristic values including a complex relative permeability and a complex relative permittivity. The larger the real part μ ′ of the complex relative permeability, the more the magnetic lines of force pass, and the higher the shielding effect of the electromagnetic wave, the higher the imaginary part μ ″ of the complex relative permeability and the permeability loss term tan δμ (= μ The smaller the “/ μ ′), the smaller the loss of magnetic field energy. Therefore, the real part μ ′ of the complex relative permeability is preferably as large as possible, and the imaginary part μ ″ of the complex relative permeability and the permeability loss term tan δμ are as small as possible. Also, as the real part ε ′ of the complex relative permittivity is large. As a result, the electric field lines are concentrated and the electromagnetic wave blocking effect is enhanced. The smaller the imaginary part ε ″ of the complex dielectric constant, the smaller the electric field energy loss. Therefore, the larger the real part ε ′ of the complex dielectric constant, the better. The smaller the imaginary part ε ″ of the complex dielectric constant, the better.

  In the present invention, the real part μ ′ and imaginary part μ ′ of the complex relative permeability and the real part ε ′ and imaginary part ε ″ of the complex relative permittivity are numerical values corresponding to the frequency of the electromagnetic wave used for wireless communication. The frequency of the electromagnetic wave used for wireless communication is not particularly limited, but may be a frequency in the range of 300 MHz to 300 GHz including the UHF band, the SHF band, and the EHF band, for example, 860 MHz to 1 GHz. The following high MHz band or 2.4 GHz band frequency may be used.

  In the present embodiment, the shield layer 13 has a relation of μ ′ ≧ μ ″ between the real part μ ′ of the complex relative permeability and the imaginary part μ ″ of the complex relative permeability with respect to the electromagnetic wave used for wireless communication. Therefore, the real part μ ′ of the complex relative permeability is equal to or larger than the imaginary part μ ″ of the complex relative permeability. The shield layer 13 is a real number of the complex relative permeability with respect to the electromagnetic wave used for wireless communication. The part μ ′ is 5 or more and the permeability loss term tan δμ is 1 or less, and the shield layer 13 has a real part μ ′ of the complex relative permeability of 10 or more with respect to electromagnetic waves used for wireless communication. The permeability loss term tan δμ is preferably 1 or less, and the real part μ ′ of the complex relative permeability is 20 or more and the permeability loss term tan δμ is 0 with respect to the electromagnetic wave used for wireless communication. It is more preferable to have a configuration of .5 or less. .

  In the present embodiment, the shield layer 13 has a real part ε ′ of a complex relative dielectric constant of 20 or more and an imaginary part ε ″ of a complex relative dielectric constant of 300 or less with respect to an electromagnetic wave used for wireless communication. The dielectric loss term tan δε (= ε ″ / ε ′) is 15 or less.

  FIG. 2 is an enlarged cross-sectional view showing the internal structure of the shield layer 13. In FIG. 2, the hatching of the magnetic powder 21 and the magnetic fine particles 22 is omitted for easy illustration. In order to obtain the material characteristic values as described above, the shield layer 13 includes, as a binder 20, powder 21 made of a magnetic material (hereinafter referred to as “magnetic powder”) and fine particles made of a magnetic material (hereinafter referred to as “magnetic powder”). 22) (referred to as “magnetic fine particles”). The shield layer 13 contains magnetic powder 21 and magnetic fine particles 22 as magnetic materials. In the present embodiment, the binder 20 is made of a polymer, for example, a non-halogen polymer, or a non-halogen mixed material obtained by mixing a material such as a non-halogen polymer and another polymer. Specific examples of the binder are merely examples, and are not limited to non-halogen polymers.

  A halogen-based polymer can be used as the binder 20. As for the binder 20, any material such as polymer (resin, TPE, rubber) gel, oligomer, etc. can be used regardless of organic type and inorganic type, and it does not depend on the degree of polymerization. Non-halogen materials can be preferably used in terms of environment. For forming a sheet, a polymer material is suitable. For example, the following materials can be preferably used, but the types of materials not listed in the examples and materials with different blending methods, alloyed materials, and the like are formed into sheets. All possible materials can be used.

  As the material of the binder 20, various organic polymer materials can be used, and examples thereof include rubbers, thermoplastic elastomers, and polymer materials including various plastics. Examples of the rubber include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-vinyl acetate rubber, butyl rubber, halogenated butyl rubber, chloroprene rubber, nitrile rubber, acrylic rubber, and ethylene. Synthetic rubber such as acrylic rubber, epichlorohydrin rubber, fluoro rubber, urethane rubber, silicone rubber, chlorinated polyethylene rubber, hydrogenated nitrile rubber (HNBR) alone, their derivatives, or modification of these by various modification treatments And the like. Liquid rubber may also be used.

  These rubbers can be used alone or in combination. In addition to vulcanizing agents, rubbers can be appropriately mixed with vulcanization accelerators, anti-aging agents, softeners, plasticizers, fillers, colorants, and the like that have been conventionally used as rubber compounding agents. it can. In addition to these, arbitrary additives can be used. For example, in order to control the dielectric constant and conductivity, a predetermined amount of dielectric (carbon black, graphite, titanium oxide, etc.) is used for impedance matching to an unnecessary electromagnetic wave generated in an electronic device which is one of applications, and temperature environment. Depending on the material, the material can be designed and added. Further, processing aids (lubricants, dispersants) may be appropriately selected and added.

  As thermoplastic elastomer, for example, chlorinated polyethylene such as chlorinated polyethylene, ethylene-based copolymer, acrylic, ethylene-acrylic copolymer, urethane, ester, silicone, styrene, amide, etc. Elastomers and their derivatives are mentioned.

  Further, various plastics include, for example, chlorine resins such as polyethylene, polypropylene, AS resin, ABS resin, polystyrene, polyvinyl chloride, and polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, fluorine resin, and silicone resin. , Thermoplastic resins such as acrylic resin, nylon, polycarbonate, polyethylene terephthalate, alkyd resin, unsaturated polyester, polysulfone, urethane resin, phenol resin, urea resin, epoxy resin, polyimide resin, biodegradable resin or thermosetting And resins and derivatives thereof. As these binders, low molecular weight oligomer types and liquid types can be used. Any material can be selected as long as it becomes a sheet after molding by heat, pressure, ultraviolet light, radiation, electron beam, air drying, curing agent, or the like.

  The magnetic powder 21 is a flat soft magnetic metal powder, dispersed so as not to contact each other, and oriented so as to extend perpendicular to the thickness direction of the shield layer 13. The magnetic powder 21 has a substantially disk shape, an average thickness dimension is 2 μm, and an average outer diameter in a direction perpendicular to the thickness direction is 55 μm. The magnetic fine particles 22 are fine particles smaller than the thickness of the metal powder, and at least the outer surface portion is non-conductive throughout, and is configured to have low conductivity. The average outer diameter of the magnetic fine particles 22 is 1 μm.

  For example, HNBR, which is hydrogenated NBR rubber, is used as the binding material 20 that forms the shield layer 13. The magnetic powder 21 is made of Sendust, which is an alloy of iron, silicon and aluminum (Fe—Si—Al), for example. The magnetic fine particles are made of, for example, iron oxide (magnetite) having a corrosion resistance while suppressing the overall conductivity. The shapes, dimensions, and materials described above are merely examples and are not intended to be limiting.

  As long as the shield layer 13 has an appropriate complex relative permeability and complex relative permittivity, the material configuration is not particularly limited. A soft magnetic powder 21 and / or magnetic fine particles 22 may be dispersed in the binder 20 as in this embodiment, and a magnetic material (metal oxide, ceramics, granular thin film, ferrite plating, metal organic compound, magnetic plating) may be used. Etc.) can be used as the shield layer 13 as they are.

  Examples of materials for the soft magnetic powder 21 and / or the magnetic fine particles 22 include sendust (Fe—Si—Al alloy), permalloy (Fe—Ni alloy), silicon steel (Fe—Cu—Si alloy), Fe -Si alloy, Fe-Si-B (-Cu-Nb) alloy, Fe-Ni-Cr-Si alloy, Fe-Cr-Si alloy, Fe-Al-Ni-Cr alloy, Fe-Ni-Cr alloy, Fe -Cr-Al-Si alloy, Fe alloy, Co alloy, Si alloy, Ni alloy, amorphous metal, and the like.

  Further, ferrite or pure iron may be used as the material of the soft magnetic powder. Examples of the ferrite include soft ferrite such as Mn—Zn ferrite, Ni—Zn ferrite, Mn—Mg ferrite, Mn ferrite, Cu—Zn ferrite, and Cu—Mg—Zn ferrite, or hard ferrite that is a permanent magnet material. . Examples of pure iron include carbonyl iron. As the material for the soft magnetic powder, these magnetic materials may be used alone or in combination.

  The soft magnetic powder may be a flat soft magnetic powder such as a plate shape including a disk shape, a spheroid shape obtained by rotating an ellipse around a short axis, or a needle shape, a fiber shape, a spherical shape, for example. Non-flat soft magnetic powders such as polyhedrons and lumps may be used. Preferably, a flat soft magnetic powder having a high magnetic permeability is used as the soft magnetic powder. As the soft magnetic powder, only one type of powder may be used, or a plurality of types of powder may be combined and used. When combining a plurality of types of powder, at least 1 The type is preferably flat.

  The particle diameter of the soft magnetic powder is 1 nm to 1000 μm, preferably 10 nm to 300 μm. In the case of flat soft magnetic powder, the aspect ratio is 2 or more and 500 or less, preferably 10 or more and 100 or less. In particular, by using nano-sized magnetic fine powder, in the shield layer in the UHF band and the SHF band, the value of the real part μ ′ of the complex relative permeability is increased to, for example, 10 or more, and the complex relative permeability is an imaginary number. The value of the part μ ″ can be lowered to 5 or less, for example.

  The soft magnetic powder may have an organic or inorganic coating layer formed on the surface thereof by a coating process such as plating, welding, or electrodeposition in order to increase insulation. The soft magnetic powder may have an oxide film on the surface in order to improve the corrosion resistance. The surface of the magnetic powder is preferably subjected to a surface treatment. As the surface treatment agent, a general treatment method using a coupling agent, a surfactant or the like can be used. Further, all means for improving the wettability between the magnetic powder and the binder, such as a resin coating and a dispersant, can be used.

  The shield layer 13 is made of a material made of or containing at least one of soft magnetic metal, soft magnetic metal oxide, magnetic metal and magnetic metal oxide as a magnetic material. The shield layer 13 has a configuration in which at least one of powder and fine particles made of at least one of soft magnetic metal, soft magnetic metal oxide, magnetic metal, and magnetic metal oxide is dispersed in the binder 20 as described above. Alternatively, it may be formed into a film including a thin film by at least one of soft magnetic metal, soft magnetic metal oxide, magnetic metal, and magnetic metal oxide.

  The shield layer 13 configured to disperse the magnetic material in the binder 20 is one or more selected from the group of ferrite, iron alloy, and iron particles as the magnetic material with respect to 100 parts by weight of the organic polymer as the binder 20. These materials are formed from a material containing 1 part by weight or more and 1500 parts by weight or less. The blending amount of the magnetic material with respect to 100 parts by weight of the organic polymer is preferably 10 parts by weight or more and 1000 parts by weight or less. If the blending amount of the magnetic material with respect to 100 parts by weight of the organic polymer is less than 1 part by weight, sufficient magnetic permeability cannot be obtained, and if it exceeds 1500 parts by weight, the workability is inferior and the sheet body 10 cannot be produced. Or manufacturing becomes difficult.

  When the shield layer 13 has the same configuration, the real part μ ′ and the imaginary part μ ″ of the complex relative permeability vary depending on the frequency of the target electromagnetic wave, and tend to decrease as the frequency of the target electromagnetic wave increases. In the present embodiment, the electromagnetic waves to be blocked include electromagnetic waves having frequencies in the high MHz band and the 2.4 GHz band, the real part μ ′ and the imaginary part μ of the complex relative permeability. "" Tends to decrease as the frequency of the target electromagnetic wave increases. Therefore, in order to achieve a configuration capable of blocking electromagnetic waves in the high MHz band and 2.4 GHz band, it is generally more complex than a configuration intended to block electromagnetic waves having a low frequency of about 1 to 10 MHz. The real part μ ′ and the imaginary part μ ″ of the relative permeability are particularly small.

  In order to increase the real part μ ′ of the complex relative permeability in the shield layer 13, it is necessary to increase the amount of the portion made of a magnetic material in the shield layer 13. Further, in order to reduce the imaginary part μ ″ of the complex relative permeability, it is only necessary to reduce the portion made of a nonmagnetic material in the magnetic flux line path 25. Considering simply, the blending amount of the magnetic powder 21 in the shield layer 13 is reduced. If the number is increased, the amount of the portion made of the magnetic material can be increased and the portion made of the non-magnetic material in the path of the magnetic field lines can be decreased. However, the amount of the magnetic powder 21 is increased too much to increase the amount of the magnetic powder 21. When they come into contact with each other, the shield layer 13 has conductivity, and a current is generated in the shield layer 13, loss due to resistance occurs, and electromagnetic energy is absorbed. The blending amount cannot be increased.

In the present embodiment, the magnetic fine particles 22 are mixed together with the magnetic powder 21 to prevent the magnetic powders 21 from coming into contact with each other, and the magnetic fine particles 22 are interposed between the magnetic powders 21 to have magnetism. It is possible to increase the amount of the portion made of the material and reduce the portion made of the nonmagnetic material in the path 25 of the magnetic field lines. Therefore, the complex relative magnetic permeability as described above can be obtained for electromagnetic waves in the high MHz band and the 2.4 GHz band. For example, the real part μ ′ of the complex relative permeability with respect to the electromagnetic wave of 950 MHz of the shield layer 13 is 19.16, the permeability loss term tan δμ is 0.58, and the real part ε ′ of the complex relative permittivity is 165.8. And the dielectric loss term tan δε is 0.15. Further, the surface resistivity (JIS K6911) of the shield layer 13 is 10 ⁶ Ω / □.

  In a high frequency range including a high MHz band and a 2.4 GHz band, even if it is a magnetic metal, the real part μ ′ of the complex relative permeability is greatly reduced, and it is difficult to obtain a high value. Further, in the GHz band of 1000 MHz or more, the sheet body 10 including the shield layer 13 in which the magnetic powder 21 is dispersed in the binder 20 is more complex than the sheet of the magnetic metal alone, and the real part μ ′ of the complex relative permeability and The imaginary part μ ”may show a high value.

  At a low frequency of about 1 MHz or more and 10 MHz or less, the real part μ ′ of the complex relative permeability of the sheet body 10 in which the magnetic powder 21 is dispersed in the binder 20 is, of course, the real part of the complex relative permeability of the sheet of magnetic metal alone. Each is smaller than μ ′. When the reduction rate of the real part μ ′ of the complex relative permeability due to the frequency increase is compared, the reduction rate of the sheet body 10 in which the magnetic powder 21 is dispersed in the binder 20 is smaller than the reduction rate of the magnetic metal single sheet. . Accordingly, the complex ratio of the sheet body 10 in which the magnetic powder 21 is dispersed in the binder 20 is such that a reverse phenomenon may occur in a high frequency range including 300 MHz or higher, particularly in the high MHz band and GHz band (1 GHz or higher and lower than 1 THz). The real part μ ′ of the magnetic permeability may be larger than the real part μ ′ of the complex relative permeability of the sheet of the magnetic metal alone. This phenomenon is caused by the magnetic powders 21 and 22 being magnetic materials being dispersed apart from each other, resulting in a magnetic loss due to the intervening material. Therefore, in the shield layer 13 of the sheet member 10, the magnetic resonance frequency is increased to the high frequency side. Therefore, this phenomenon is caused by shifting from the MHz band (1 MHz or more and less than 1 GHz) side to the GHz band side.

  Further, as shown in Snoek's limit law, there is a decrease due to the frequency increase of the real part μ ′ of the complex relative permeability, and in conjunction with the decrease rate of the real part μ ′ of the complex relative permeability with respect to the frequency increase, The imaginary part μ ”of the magnetic susceptibility is large. In a high frequency range including 300 MHz or more, particularly in the high MHz band and the GHz band, the real part μ ′ and the imaginary part μ The characteristics are that “both are large or the real part μ ′ of the complex relative permeability is small and the imaginary part μ of the complex permeability is large”. High frequency including 300 MHz or more, particularly including high MHz band and GHz band In the region, it is difficult to obtain characteristics that the real part μ ′ of the complex relative permeability is large and the imaginary part μ ″ of the complex relative permeability is small.

  The magnetic material has a tendency that as the real part μ ′ of the complex relative permeability in the low frequency region is larger, the reduction rate of the real part μ ′ of the complex relative permeability due to the frequency increase is larger. By dispersing the powder (magnetic powder) 21 of the magnetic material having such a tendency in the binder 20, the rate of decrease in the real part μ ′ of the complex relative permeability due to the frequency increase is suppressed, and the magnetic powders 21 are in contact with each other. Insulation can be ensured. Further, in the configuration in which the magnetic powder 21 is only dispersed in the binder 20, the complex relative permeability in the high frequency range including 300 MHz or more, particularly including the high MHz band and the GHz band, due to the influence of the binder 20 existing between the magnetic powders 21. There is a limit to increasing the real part μ ′ of the magnetic susceptibility. Therefore, it is necessary to construct a path having a high real part μ ′ of the complex relative permeability called a magnetic field path at a micro level so that the magnetic lines of force can easily pass through the shield layer 13 of the sheet body 10. Magnetic fine particles 22 are mixed to form this magnetic field path. Of course, it is necessary to ensure high electrical insulation between the magnetic powders 21 so that the shield layer 13 does not have a conductive structure by forming the magnetic field path. Ensuring this electrical insulation is realized, for example, as a structure in which the magnetic fine particles 22 are nonconductive at least on the entire outer surface. In the present embodiment, ferrite nanoparticles are used as the magnetic fine particles 22. Since these particles are oxide magnetic materials, they do not exhibit electrical conductivity.

  In this way, the resonance frequency at which the imaginary part μ ″ of the complex relative permeability becomes a peak value shifts to the high frequency side and further increases to 5 GHz and 10 GHz, so that it is 300 MHz or more, particularly in the high MHz band and 2.4 GHz band. It is possible to realize the shield layer 13 in which the real part μ ′ of the complex relative permeability is large and the imaginary part μ ″ of the complex relative permeability is small.

In addition, as a shield layer 13 according to another embodiment of the present invention, two kinds of magnetic particles having different average particle diameter ratios of about 4: 1 are used in the same manner as described above in order to increase the filling rate of the magnetic material. The magnetic fine particles and soft magnetic metal fibers are mixed. Furthermore, in order to ensure electrical insulation, electrically insulating fine particles are mixed. The two types of magnetic particles are made of the same material as the magnetic powder 21, and the larger average particle diameter is about 20 μm, and the smaller average particle diameter is about 5 μm. The magnetic fine particles and the soft magnetic metal fibers are made of an iron-based material, and the average particle diameter of the magnetic fine particles and the average fiber diameter of the soft magnetic metal fibers are about 1 μm. The electrically insulating fine particles are made of silicon oxide (SiO ₂ ) and have an average particle diameter of about 10 nm. The fine particles of this size also have a role of controlling the direction and interval when the magnetic powder 21 is dispersed in the shield layer 13.

  Furthermore, in order to eliminate the gap in the shield layer 13 as much as possible, the measured specific gravity value of the shield layer 13 is designed and manufactured so as to be as close as possible to the theoretical specific gravity value from the blend. In the configuration shown in FIG. 2 instead of the configuration shown in FIG. 2, similarly, the resonance frequency at which the imaginary part μ ″ of the complex relative permeability becomes a peak value is shifted to the high frequency side, and further 5 GHz and 10 GHz. To realize a shield layer 13 having a large real part μ ′ of complex relative permeability and a small imaginary part μ ″ of complex relative permeability in 300 MHz or higher, particularly in a high MHz band and 2.4 GHz band. Is possible.

  The basic idea of the material design of the shield layer 13 of the present embodiment is that the shield layer 13 has a high resistance at the communication frequency, and increases the real part μ ′ of the complex relative permeability at the communication frequency so that the magnetic field component is shielded. 13, and by aligning and arranging the flat magnetic powder microscopically, magnetic anisotropy is imparted by facilitating the flow of magnetism in an arbitrary direction, and the imaginary part μ ″ of the complex relative permeability is lowered. Thus, the magnetic loss can be suppressed, and the effect of the present invention can be obtained.

  Moreover, as for the sheet | seat body 10, a flame retardant or a flame retardant adjuvant is added to at least any one layer of each layer 13-16, for example. Accordingly, flame retardancy is imparted to the sheet body 10. For example, an electronic device such as a mobile phone may be required to be flame retardant for an interior polymer material.

  The flame retardant for obtaining such flame retardancy is not particularly limited. For example, phosphorus compounds, boron compounds, bromine flame retardants, zinc flame retardants, nitrogen flame retardants, hydroxide series Flame retardants, metal compound flame retardants, and the like can be used as appropriate. Examples of phosphorus compounds include phosphate esters and titanium phosphate. Examples of the boron compound include zinc borate. Examples of brominated flame retardants include hexabromobenzene, hexabromocyclododecane, decabromobenzyl phenyl ether, decabromobenzyl phenyl oxide, tetrabromobisphenol, ammonium bromide and the like. Examples of the zinc-based flame retardant include zinc carbonate, zinc oxide, and zinc borate. Examples of nitrogen-based flame retardants include triazine compounds, hindered amine compounds, or melamine compounds such as melamine cyanurate and melamine anidine compounds. Examples of the hydroxide flame retardant include magnesium hydroxide and aluminum hydroxide. Examples of the metal compound flame retardant include antimony trioxide, molybdenum oxide, manganese oxide, chromium oxide, and iron oxide.

  In this example, the binder is 100, the bromine-based flame retardant is 20, the antimony trioxide is 10 and the phosphoric acid ester is 14 in the weight ratio, so that it corresponds to V0 in the UL94 flame retardant test. The flame retardancy can be obtained. The sheet body 10 can be suitably used as a material constituting such an article or attached to the article. For example, it can be suitably used by being mounted on an article used in a space where it is desired to prevent combustion and generation of gas accompanying it, such as an apparatus in an aircraft, a ship, and a vehicle.

The sheet body 10 has electrical insulation. Specifically, the surface resistivity (JIS K6911) of the sheet body 10 is 10 ² Ω / □ or more because each of the layers 11 and 12 is made of the material as described above. The surface resistivity of the shield layer 13 is preferably as large as possible. Therefore, the maximum value that can be realized is the upper limit value of the surface resistivity. Thus, it has a high surface resistivity and electrical insulation.

  The sheet body 10 has heat resistance. Specifically, the heat resistance temperature of the sheet body 10 when a crosslinking agent is added to the rubber or resin material is 150 ° C., and the sheet body 10 changes in characteristics until the temperature reaches at least 150 ° C. Does not occur.

  The sheet body 10 is given thermal conductivity. The environment in which the sheet member 10 is used may be used in the vicinity of a heat source such as a communication unit including an IC and a power source unit. Due to the excellent thermal conductivity of the sheet body 10, the heat generated by the means serving as a heat source can be released, the temperature rise of the means serving as the heat source is suppressed, and the performance deteriorates due to exposure to high temperatures. Can be prevented.

  At least one surface portion of the sheet body 10 has adhesiveness or adhesiveness. In this Embodiment, it has the sticking agent layer 15 as mentioned above, and the surface part of the thickness direction other side has adhesiveness or adhesiveness by this. The sheet body 10 can be attached to the article by the bonding force due to the adhesiveness or adhesiveness of the adhesive agent layer 15. Therefore, the sheet member 10 can be easily provided between the antenna element 11 and the communication disturbing member 12 or in the vicinity of the antenna element by sticking to the communication disturbing member 12, for example. The sheet body 10 is provided with one side in the thickness direction arranged on the antenna element 11 side and the other side in the thickness direction arranged on the communication disturbing member 12 side. For example, Nitto Denko Corporation No. 5000N is used.

  EXAMPLES Hereinafter, although an Example is given and the evaluation method of this invention is demonstrated in detail, this invention is not limited to a following example.

  In Example 1, 100 parts by weight of hydrogenated nitrile rubber (HNBR, “Zeppol” manufactured by Nippon Zeon Co., Ltd.) as binder 20 and Sendust (Fe—Si—Al alloy) as flat soft magnetic powder (magnetic metal) 21 (Dowa) Mining DT) 690 parts by weight and magnetic fine particles 22 were added (filled) with 69 parts by weight of ultrafine iron powder (manufactured by JFE Chemical), a surfactant and a dispersant were added, and a peroxide (manufactured by NOF Corporation) Product name “Permicle D”) was added as a crosslinking agent, and a shield layer 13 was formed by a hot press method, and a sheet body 10 having such a shield layer 13 was produced. In the blending, the polymer fraction is 45.3 vol.% And the magnetic substance fraction is 46.4 vol.%.

  The actual specific gravity value was calculated from the weight / volume of the sheet obtained above, and the theoretical specific gravity value was calculated by dividing the specific gravity of each component × the total content by the volume. The theoretical specific gravity value in this example was 3.89, and the measured specific gravity value was 3.53.

  With respect to the shield layer 13 obtained above, the material constants (the real part μ ′ and the imaginary part μ ″ of the complex relative permeability, the real part ε ′ and the imaginary part ε ″ of the complex relative permittivity were measured by the coaxial tube method. Specifically, a ring-shaped sample having the same configuration as that of the shield layer 13 and having an outer diameter of 7 mm and an inner diameter of 3 mm is prepared, and a conductive paint is applied to the contact portion of the sample inside the coaxial tube and dried. The portion is connected to a network analyzer 8720ES manufactured by Agilent Corporation via a coaxial cable, and S11 (reflection attenuation strength) and S21 (transmission attenuation strength) are measured. From this, the real part μ ′ and the imaginary part of the complex relative permeability are measured. In addition, the real part ε ′ of the complex relative permittivity and the imaginary part ε ″ of the complex relative permittivity are measured in the same manner as the real part μ ′ and the imaginary part μ ″ of the complex relative permeability. Complex relative permeability real When referring to one or more parts mu 'and an imaginary part mu "and the real part of the complex relative permittivity epsilon' and imaginary part epsilon" unspecified, some cases that the material constants.

FIG. 3 is a graph showing measurement results of material constants μ ′, μ ″, ε ′, ε ″ in Example 1. In FIG. 1, “◆” indicates the real part μ ′ of the complex relative permeability, “■” indicates the imaginary part μ ”of the complex relative permeability, and“ Δ ”indicates the complex relative dielectric. And the imaginary part ε ″ of the complex relative permittivity is indicated by the symbol “x”. As shown in Table 1 and FIG. 3, the real part μ ′ of the complex relative permeability with respect to the electromagnetic wave of 950 MHz. Is 19.16, the permeability loss term tan δμ is 0.58, the real part ε ′ of the complex relative permittivity is 165.8, and the permittivity loss term tan δε is 0.15. The rate (JIS K6911) is 10 ⁶ Ω / □.

  FIG. 4 is a cross-sectional view showing the tag 30 including the sheet body 10 in a simplified manner. FIG. 5 is a perspective view showing the tag 30. The tag 30 is one of electronic information transmission devices that transmit information by wireless communication. For example, the tag 30 is used as a transponder of an RFID (Radio Frequency IDentification) system used for automatic recognition of solid objects. The tag 30 includes an electric field type antenna element 11, an integrated circuit (hereinafter referred to as “IC”) 17 that is electrically connected to the antenna element 11 and communicates with the antenna element 11, and the sheet body 10. It has. The tag 30 is configured to transmit a signal representing information stored in the IC 17 by the antenna element 11 when a request signal from the reader is received by the antenna element 11. Therefore, the reader can read the information held in the tag 30. The tag 30 is attached to a product, for example, and is used for product management such as prevention of product theft and grasping of inventory status. An antenna device is configured including the antenna element 11 and the sheet body 10. Although not shown in FIG. 4, a matching circuit may be added.

  The antenna element 11 which is an antenna means is a dipole antenna as described above. The antenna element 11 is realized by a pattern conductor formed on a surface portion on one side in the thickness direction of a base material 18 made of polyethylene terephthalate (PET). The IC 17 is disposed, for example, at the center of the antenna element 11 and is electrically connected. The IC 17 has at least a storage unit and a control unit. Information can be stored in the storage unit, and the control unit can store information in the storage unit or read information from the storage unit. In response to a command represented by the electromagnetic wave signal received by the antenna element 11, the IC 17 stores information in the storage unit or reads information stored in the storage unit, and outputs a signal representing the information to the antenna element 11. To give. The base material 18 has a rectangular plate shape, and the antenna element 11 is provided in the center portion of the base material 18 so as to extend in the longitudinal direction. The thickness dimension of the layers of the antenna element 11 and the IC 17 is 1 nm or more and 500 μm or less, and the thickness dimension of the layer of the substrate 18 is 0.1 μm or more and 2 mm or less. The structure which does not use a base material by printing and processing the antenna element 11 directly on the sheet | seat body 10 may be sufficient.

  A tag main body 33 is configured by the antenna element 11, the IC 17, and the base material 18. The tag main body 33 is packaged by being mounted on a flexible adhesive tape. A tag 30 is configured by the tag body 33 and the sheet body 10. Although shown in a simplified manner in FIG. 4, the sheet body 10 is laminated on the tag main body 33 in a state of being attached. Although not shown in FIG. 4, an adhesive or an adhesive is used between the tag main body 33 (there is also a configuration not including the base material 18) and the sheet body 10, or the tag main body 33 or the sheet body 10 is used. In some cases, either or both of them may be attached by stickiness or adhesiveness. The tag body 33 has a surface portion opposite to the side on which the antenna element 11 and the IC 17 are provided facing the sheet body 10, and is coupled to the shield layer 13 of the sheet body 10 from the opposite side to the layer such as the conductor layer 14. The The coupling structure between the sheet body 10 and the tag main body 33 is not particularly limited, but may be coupled using a binder including an adhesive and an adhesive. In FIG. 3, a configuration for coupling the sheet body 10 and the tag main body 33 is omitted. The tag 30 has a layer of the antenna element 11 and the IC 17, a layer of the base material 18, a shield layer 13, a binding layer 16, a conductor layer 14, and an adhesive layer 15 in this order from one side to the other side in the thickness direction. Has been. The sheet body 10 and the base material 18 are formed in the same rectangular shape. As described above, the tag main body 33 may have the orientation shown in FIG. 4 or may be configured upside down in the drawing.

  The antenna element 11 can transmit an electromagnetic wave signal in a direction intersecting with the direction in which the antenna element 11 extends, and can receive an electromagnetic wave signal coming from a direction intersecting with the direction in which the antenna element 11 extends. In the present embodiment, an electromagnetic wave signal is transmitted in the transmission / reception direction A toward the opposite side of the base material 18 and the sheet body 10 with the antenna element 11 as a reference, and the electromagnetic wave signal arriving from the transmission / reception direction A is received. it can. Although the transmission / reception direction A indicates the main direction, there is a case where communication is performed using a wraparound radio wave, and thus the transmission / reception direction A is not limited to that direction.

  The tag 30 includes information to be stored in advance (hereinafter referred to as “main information”) and information for instructing to store the main information (hereinafter referred to as “storage command information”) from, for example, an information management device that is a reader. Is received by the antenna element 11, an electrical signal representing main information and storage command information is given from the antenna element 11 to the IC 17. The IC tag 17 causes the control unit to store main information in the storage unit based on the storage command information.

  An electromagnetic wave signal representing information (hereinafter referred to as “transmission command information”) for instructing to transmit information stored in the storage unit (hereinafter referred to as “storage information”) is received by the antenna element 11 from the information management device. Then, an electric signal representing transmission command information is given from the antenna element 11 to the IC 17. As for IC tag 17, a control part reads the information (memory | storage information) memorize | stored in a memory | storage part based on transmission command information, and gives the electrical signal showing the memory | storage information to the antenna element 11. FIG. As a result, an electromagnetic wave signal representing stored information is transmitted from the antenna element 11.

  Thus, the tag 30 is an electronic information transmission device that transmits and receives an electromagnetic wave signal by the antenna element 11. The tag 30 may be a battery-driven tag that is driven by a built-in battery, or may be a battery-less tag that returns an electromagnetic wave signal using the energy of the received electromagnetic wave signal.

  Such a tag 30 includes a sheet body 10 so that the tag 30 can be used in the vicinity of the communication blocking member 12. As an example, the sheet body 10 is provided on the side opposite to the transmission / reception direction A with respect to the antenna element 11. The sheet body 10 is used by being attached to the communication disturbing member 12 using the adhesive agent layer 15. In the tag 30, the sheet body 10 is disposed closer to the communication interference member 12 than the antenna element 11, and the sheet body 10 is interposed or disposed between the antenna element 11 and the communication interference member 12 or in the vicinity of the antenna element. Is provided.

  FIG. 6 is a cross-sectional view showing an electric field formed in the vicinity of the antenna element 11 in a state where the tag 30 is attached to the communication disturbing member 12. FIG. 7 is a cross-sectional view showing an electric field formed in the vicinity of the antenna element 11 in a state where the antenna element 11 and the IC tag 17 are arranged in the vicinity of the communication disturbing member 12 without the sheet body 10 interposed. FIG. 6 shows the configuration of the tag 30 except the antenna element 11, the IC 17, and the shield layer 13 in order to facilitate understanding. In the free space where the communication disturbing member 12 does not exist in the vicinity of the antenna element 11, the electric field generated by the potential difference between the both ends 11a and 11b of the antenna element 11 spreads in the space as it is, and a magnetic field is formed by the change in electric field strength. An electric field is formed by a change in the strength of the magnetic field. The antenna element 11 can transmit an electromagnetic wave by utilizing the principle that such a phenomenon of forming an electric field and a magnetic field is successively repeated. The antenna element 11 can receive an electromagnetic wave having a resonance frequency by a principle opposite to the transmission principle.

  As shown in FIG. 7, when the communication disturbing member 12 exists in the vicinity of the antenna element 11, the electric field generated at both ends of the antenna element 11 cannot ignore the electrical influence received from the communication disturbing member 12, Although it depends on the frequency, a short-circuit phenomenon occurs in the frequency band above the MHz band, and as a result, the impedance of the antenna element 11 is lowered.

  That is, in a state where a potential difference is generated between both end portions 11a and 11b of the antenna element 11, both end portions 11a and 11b of the antenna element 11 are charged positively or negatively, respectively, and thereby both end portions 11a and 11b of the antenna element 11 are charged. And an electric field is formed between the opposite end portions 11a and 11b of the antenna element 11 and the opposite portions 12a and 12b of the communication interference member 12, and the opposite ends 11a and 11b of the antenna element 11 are charged in the opposite direction. It becomes. An alternating voltage is applied to the antenna element 11 by the IC, and both end portions 11a and 11b are charged so that positive and negative are alternately switched. In synchronization with this, the portions 12a and 12b in the communication disturbing member 12 are also charged. , They are charged so that positive and negative are alternately switched. Hereinafter, in FIGS. 6 and 7, the left end portion of the antenna element 11 is defined as one end portion 11 a, and the right end portion is defined as the other end portion 11 b, and the left portion of the portions 12 a and 12 b of the communication disturbing member 12. Is the one portion 12a and the right portion is the other portion 12b.

  Observing the minute time, a current I11 directed from the other end 11b of the antenna element 11 toward the one end 11a is generated, and a current I12 directed from the one portion 12a to the other portion 12b is generated in the communication disturbing member 12. In this way, a reverse current is generated. As described above, since an alternating voltage is applied to the antenna element 11 by the IC, a state in which a current having a direction shown in FIG. 7 is generated and a state in which a current having a direction opposite to that in FIG. When the frequency is increased, it is as if a current flows between one end portion 11a of the antenna element 11 and one portion 12a of the communication jamming member 12, and between the other end portion 11b of the antenna element 11 and the other portion 12b of the communication jamming member 12. It becomes a state equivalent to the occurrence of I0, between the one end portion 11a of the antenna element 11 and the one portion 12a of the communication disturbing member 12, and the other end portion 11b of the antenna element 11 and the other portion 12b of the communication disturbing member 12. Is equivalent to a short circuit. In other words, it is short-circuited at a high frequency. This phenomenon of short-circuiting at a high frequency is the same phenomenon as when a high-frequency voltage is applied to the capacitor, the state is similar to that when the capacitor is energized.

  When such a high-frequency short circuit occurs, a closed circuit is formed by the antenna element 11 and the communication disturbing member 12, and the current value increases as compared with the case where the communication disturbing member 12 does not exist in the vicinity. That is, the impedance is reduced as compared with the case where there is no communication disturbing member 12 in the vicinity of the antenna element 11. Assuming that the impedance is Z, the voltage value is V, and the current value is I, the impedance Z is Z = V / I, and since the current value I increases, the impedance Z is confirmed to decrease. ing. The impedance Z is an impedance of a circuit formed by the antenna element 11 and the communication disturbing member 12, but is also an input impedance of the antenna element 11 constituting the circuit. Therefore, when the communication disturbing member 12 exists in the vicinity of the antenna, the input impedance of the antenna element 11 is lowered.

  On the other hand, as shown in FIG. 6, when the sheet body 10 is provided between the electric field type antenna element 11 and the communication disturbing member 12, both end portions 11a and 11b of the antenna element 11 are charged, The strength of the electric field formed between the communication disturbing member 12 is reduced. Therefore, the formation of a high-frequency short circuit is weakened, and a reduction in input impedance of the antenna element 11 is suppressed. The suppression of the decrease in input impedance is confirmed because the current value of the current generated in the antenna element 11 becomes a small value close to the case where the communication disturbing member 12 is not present. By using the sheet body 10 in this way, it is possible to suppress a decrease in input impedance.

  The present inventor uses the numerical values of the material constants μ ′, μ ″, ε ′, ε ″ of Example 1 shown in Table 1 and FIG. 3 to provide an antenna element that is a dipole antenna in the vicinity of the metallic communication disturbing member 12 11, the impedance recovery degree of the antenna element 11 was calculated by an electromagnetic field simulator (Sonnet) with the sheet member 10 being sandwiched between the antenna element 11 and the communication interference member 12 or in the vicinity of the antenna element.

  The configuration used for the simulation is as shown in FIG. The conductor layer 14 has a copper (Cu) plate which is a metal plate, is provided with an adhesive layer 16 having a thickness of 50 μm and a shield layer 13 having a thickness of 500 μm, and an antenna serving as an antenna element on a PET film having a thickness of 100 μm. Element 11 is arranged. As a result, the input impedance was 126Ω (in the case of 1 GHz, the frequency with zero reactance) and the radiation efficiency was 3% (gain −12.6 dB).

  The sheet body 10 is provided by a member having a portion made of a conductive material when the antenna element 11 is disposed in the vicinity of the communication disturbing member by being provided between the electric field type antenna element 11 and the communication disturbing member 12. A reduction in input impedance of the antenna element can be suppressed. If the sheet member 10 is not used, the electric field type antenna element 11 hardly operates in the vicinity of the communication disturbing member 12 and cannot be used for wireless communication. This is because the input impedance of the electric field type antenna element 11 is significantly reduced. When the input impedance of the electric field type antenna element 11 decreases, the impedance of the IC 17 that communicates using the electric field type antenna element 11 deviates, and a signal can be passed between the electric field type antenna element 11 and the IC 17. It becomes impossible. The sheet body 10 can suppress a decrease in input impedance of the antenna element 11 when the antenna element 11 is disposed in the vicinity of a member having a portion made of a conductive material. Although it is an electric field antenna, it is desired to increase the dielectric constant and dielectric loss. To increase the dielectric loss (tan δε = ε ″ / ε ′), it is necessary to increase the imaginary part ε ″ of the complex relative dielectric constant. However, if the imaginary part ε ″ of the complex relative permittivity becomes larger than necessary, the conductivity increases, which contributes to the direction of advancing the short circuit. In the present invention, means for controlling the permeability in addition to the permittivity In other words, the impedance is efficiently recovered, that is, the combination of the dielectric constant and the magnetic permeability allows the communication improvement effect to be obtained by not increasing the conductivity too much. 10, wireless communication can be suitably performed using the electric field type antenna element 11 even in the vicinity of the communication disturbing member 12.

  Specifically, when the antenna element 11 is a dipole antenna, the IC 17 is connected to the center portion of the dipole antenna. The impedance of the IC 17 is, for example, 40Ω or 50Ω. To achieve matching with this impedance, at least the impedance of the antenna needs to be about 10Ω.

  This is because when a metal is brought close to the antenna element 11, resistance decreases and impedance also decreases. As a calculation example, when the sheet body 10 is not used, if there is only a dielectric having a thickness of 0.53 mm between the antenna element 11 and the communication disturbing member 12, the impedance is 0.85Ω. This number is too small compared to 40Ω. In the tag 30, the antenna element 11 and the IC 17 are directly attached to simplify the configuration. A circuit for adjusting impedance is not provided on the way. Therefore, the impedance difference is fatal. On the other hand, by providing the sheet body 10, it is possible to suppress a decrease in input impedance of the antenna element 11.

  Further, in order to suppress the attenuation of electromagnetic energy, attention is paid to the generation of a magnetic field component during energy attenuation, the magnetic part is collected by increasing the real part μ ′ by adjusting the complex relative permeability of the sheet body 10, and μ ″ is The energy of the collected magnetic field is prevented from being converted into thermal energy by reducing the size of the sheet body 10. Thus, when adjusting the complex permeability of the sheet body 10, as compared with the case of adjusting the complex relative permittivity of the sheet body 10, It is easy to obtain the effect of suppressing the attenuation of electromagnetic energy, because the magnetic field becomes stronger as it is closer to the generation source, so that even if it is a thin sheet, it works effectively if the complex relative permeability is adjusted.

Further, by suppressing the loss of electromagnetic energy, the radiation efficiency can be increased as the antenna characteristic of the antenna element 11. Radiation efficiency η = 10 ^{(gain-directivity gain) / 10} . The directivity gain is a gain that does not include a loss of metal or the like. The gain (usually, when it is written only as “Gain”) is the “true gain” including loss. As a result of calculation, it was found that the loss should be reduced in order to improve (increase) the radiation efficiency. Further, when the radiation resistance of the antenna is Rrad and the loss resistance is Rloss, the radiation efficiency η = Rrad / (Rrad + Rloss). Since Rrad corresponds to the resistance of the input impedance of the lossless antenna, the radiation efficiency decreases when the resistance is lowered by bringing a metal close to the antenna element 11. For this reason, radiation efficiency can be increased by suppressing a decrease in input impedance of the antenna element 11.

  Furthermore, since the length of the antenna element 11 is affected by the wavelength shortening effect due to the complex relative permittivity and the complex relative permeability of the sheet member 10, the frequency needs to be readjusted. Considering the influence of this shortening of wavelength, severe manufacturing conditions are required. In order to avoid this, it is required to make the real part of the complex relative permittivity that tends to take a large numerical value as small as possible.

  As the antenna element 11, a dipole antenna can be used. Thus, wireless communication can be performed using a dipole antenna having a simple and small configuration in the vicinity of the communication disturbing member 12.

  Further, the sheet body 10 is provided with a shield layer 13, and the shield layer 13 has a real part μ ′ of complex relative permeability μ ′ and an imaginary part μ ″ of complex relative permeability μ for electromagnetic waves used for wireless communication. “≧ μ”, preferably the real part μ ′ of the complex relative permeability is 5 or more and the permeability loss term tan δμ ≦ 1, more preferably, the real part μ ′ of the complex relative permeability is 20 That is the above and the permeability loss term tan δμ ≦ 0.5. The shield layer 13 has a real part ε ′ of a complex relative dielectric constant of 20 or more with respect to electromagnetic waves used for wireless communication. Further, the shield layer 13 has an imaginary part ε ″ of a complex relative dielectric constant of 300 or less with respect to an electromagnetic wave used for wireless communication. Thereby, when the antenna element 11 is arranged in the vicinity of the communication disturbing member 12, It is possible to realize a sheet body that can suppress a decrease in input impedance of the antenna element 11 due to the communication disturbing member 12 and can suppress a loss of electromagnetic energy due to the communication disturbing member 12.

  Although a graph and the like are omitted, an example of a simulation result of radiation efficiency when the real part μ ′ of the complex relative permeability in the 950 MHz band is 50 and the permeability loss term tan δμ = 0.1 will be described. Was 13Ω (in the case of 1 GHz, the frequency with zero reactance), and the radiation efficiency was 8% (gain −5.1 dB).

  FIG. 8 is a cross-sectional view illustrating a configuration of the sheet body 10 assumed in a simulation for confirming the effect of the sheet body 10 when a dipole antenna is used as the antenna element 11. In this simulation, the sheet body 10 has only the shield layer 13, and the antenna element 11 is provided with the sheet body 10 (shield layer 13) via a dielectric layer corresponding to the base material 18. The communication state was simulated for the configuration in which the communication disturbing member 12 was directly laminated on the sheet body 10 (shield layer 13) so that 13) was disposed between the antenna element 11 and the communication disturbing member 12 made of a metal plate. .

  FIG. 9 is a graph showing a simulation result by the configuration of FIG. 8 and showing a relationship between the frequency and the real part (Real) and the imaginary part (Imaginary) of the input impedance of the antenna element 11. The frequency at which the imaginary part of the input impedance becomes zero indicates the resonance frequency (953 MHz in FIG. 9). FIG. 10 is a graph showing a simulation result by the configuration of FIG. 8 and showing a directivity gain. FIG. 11 is a graph showing a simulation result by the configuration of FIG. 8 and showing an absolute gain.

  Table 1 shows the material constants of each layer having the configuration shown in FIG. Each material constant is a value at a frequency of 950 MHz.

In this simulation, as a dielectric layer corresponding to the base material 18, a dielectric part having a layer thickness of 1 mm with a real part ε ′ of a complex relative dielectric constant of 950 MHz band being 1.1 and a dielectric loss term tan δε = 0.01. Assuming a body layer (for example, a foam layer such as styrene foam), the real part ε ′ of the complex relative permittivity in the 950 MHz band is 100, the dielectric constant loss term tan δε = 0.01, the real part μ of the complex relative permeability μ The shield layer 13 in which 'is 50, the permeability loss term tan δμ = 0.01, and the conductivity 10 ⁻⁴ [S / m] was assumed. A dielectric layer (base material 18) is disposed on the antenna element 11 side, and a shield layer 13 is laminated on the dielectric layer as a sheet 10 on the side opposite to the antenna element 11. As a result of such a simulation, the input impedance (real part) becomes 30Ω at 953 MHz where the imaginary part (reactance) of the input impedance is zero, and the directivity gain is 6.696 dBi (θ (Theta) in FIG. 10). The absolute gain was 0.266 dBi (value in the case of θ (Theta) = 0 in FIG. 11), and the radiation efficiency was 22.53%.

  In the conventional technique, the use of a magnetic sheet has not been studied in response to the metal-related problem of the electric field type antenna element 11, that is, the problem with respect to the communication disturbing member 12. This is because the electric field type antenna element mainly uses an electric field, and thus a dielectric constant that is naturally effective for the electric field has been discussed, and the effect of the magnetic permeability has not been sufficiently noted. That is, the impedance recovery effect by the sheet 10 having magnetic permeability has not been known.

  The impedance recovery effect using the magnetic permeability (which also uses the dielectric constant) is great, and the input impedance of the antenna element 11 due to being arranged in the vicinity of the communication disturbing member 12 drops to near 0Ω. When the real part μ ′ of the complex relative permeability of 11 is set to 10 or more (in the high MHz band or 2.4 GHz band), it is recovered to around several tens of Ω. As a result, matching can be made with the impedance inherent to the IC connected to the communication means and the antenna element 11, for example, 30Ω and 50Ω, and it becomes possible to operate as a resonance circuit including the antenna element.

  Next, regarding the loss of electromagnetic energy, if the value of the imaginary part μ ″ of the complex relative permeability of the shield layer 13 is large, the loss increases, and as a result, the radiation efficiency of the antenna element 11 decreases. When the permeability loss term tan δμ of the permeability is 1 or less (in the high MHz band or 2.4 GHz band), the loss is slightly reduced, and the permeability loss term tan δμ of the complex relative permeability is 0.5 or less (high MHz band). Or in the 2.4 GHz band), the loss of electromagnetic energy is further reduced, and the radiation efficiency of the antenna element 11 is improved.

The real part ε ′ of the complex relative permittivity of the shield layer 13 contributes to the wavelength shortening effect that determines the size of the antenna element together with the real part μ ′ of the complex relative permeability. By setting the real part ε ′ of the complex relative dielectric constant to 20 or more, the size of the antenna element 11 can be reduced to about 1/4.
The imaginary part ε ″ of the complex dielectric constant of the shield layer 13 is set to 300 or less.

Where ω is an angular frequency (ω = 2πf), ε ₀ is a vacuum dielectric constant (8.8541 × 10 ¹² [F / m], and f is a frequency [Hz]. The shield layer of the present invention is made of a conductive material. However, if the frequency is 950 MHz, the conductivity is σ≈15.9 S / m (resistivity ρ≈0.06 Ωm) and the frequency is 2.4 GHz. In this case, a conductivity σ≈39.9 S / m (resistivity ρ≈0.02 Ωm) is obtained, and it may be roughly considered that it has a conductivity lower than these and a resistivity higher than this.

  The shield layer 13 is a material made of at least one of soft magnetic metal, soft magnetic metal oxide, magnetic metal, and magnetic metal oxide, or a material containing it. There is no particular limitation on the method for developing magnetism, but it is realized depending on whether these materials are used directly or dispersed in a binder. With this configuration, it is possible to form a shield layer that can obtain the aforementioned characteristics. Therefore, it is possible to realize the sheet body 10 that achieves the above-described excellent effects.

  Further, since the sheet body 10 has the conductor layer 14, the shield body 14 is shielded in accordance with the frequency of the electromagnetic wave used for the above-described wireless communication in a state where the conductor layer 14 made of a conductive material exists in the vicinity of the antenna element 11. The real part μ ′ and the imaginary part μ ″ of the complex relative permeability of the layer 13 and the real part ε ′ and the imaginary part ε ″ of the complex relative permittivity are adjusted. Thereby, suitable characteristics of the shield layer 13 can be realized. Therefore, more suitable wireless communication can be realized in the vicinity of the communication disturbing member 12.

  Further, the antenna element 11 can be downsized by combining the dipole antenna and the sheet body 10 as the antenna element 11. Combined with the height of the real part μ ′ of the complex relative permeability and the real part ε ′ of the complex relative permittivity of the sheet body 10, a wavelength shortening effect is added, and the size can be significantly reduced as compared with the conventional product. it can. The dipole antenna is linear, may have a curve and a bend, and the total length only needs to be λ / 2. For example, at 950 MHz, the length is about 15.8 cm, but the effect of shortening the wavelength by this sheet body is added to this, so that a linear element of about 3 to 10 cm becomes possible, and further bending is applied to a label of 2 to 3 cm. The size that fits is possible. Furthermore, it can also be reduced in size and the object which can be pasted will spread over a wide range.

  In the conventional product, there is a patch antenna as an antenna that operates in the vicinity of the communication disturbing member 12. However, the size of the patch antenna requires one side λ / 2. For example, at 950 MHz, the patch antenna becomes a square shape having a maximum of about 15.8 cm square. Specifically, it does not fit in the card size and is too large as a tag. In general, the distance between the patch and the ground conductor also needs to be λ / 16 to λ / 64, and cannot be used for applications requiring small size and flexibility.

  FIG. 12 is a simplified perspective view showing a tag 30 according to another embodiment of the present invention. The tag 30 illustrated in FIG. 12 has a configuration similar to that of the tag 30 described with reference to FIGS. 1 to 11, and the same reference numerals are given to the corresponding configurations, and only different points will be described. 1 to 11 uses a dipole antenna as the antenna element 11, the tag 30 shown in FIG. 12 uses a monopole antenna as the antenna element 11. In the dipole antenna, the IC 17 is provided in the central portion of the antenna element 11, that is, between the two element pieces constituting the antenna element 11. However, in the monopole antenna, one of the two element pieces is grounded. In this configuration, the plate 100 can be replaced. The tag 30 configured using such a monopole antenna can obtain the same effects as the tag 30 configured using the dipole antenna as described above. The effect of the sheet body 10 is obtained similarly. Furthermore, the size can be further reduced as compared with the case of using a dipole antenna.

  In this way, by using the sheet body 10, the tag 30 using the antenna element 11 is attached to the communication jamming member 12, for example, and is provided in the vicinity of the communication jamming member 12, thereby realizing suitable transmission and reception of electromagnetic wave signals. The tag 30 can be used in a ready state. Therefore, for example, the tag 30 can be attached to a beverage 40 in which a beverage is accommodated in a metal container that is a communication blocking member 12 as shown in FIG. 13, for example, for the purpose of product management. Further, the tag 30 is incorporated in an electronic device 41 such as a cellular phone device in which a large number of communication blocking members 12 such as a substrate as shown in FIG. 14 are used, for example, for merchandise management or user authentication, theft prevention, etc. Can be used for purposes. Thus, the wide use of the tag 30 can be ensured, and the highly convenient tag 30 can be realized.

  Further, since the sheet body 10 has flexibility as described above, it can be freely deformed. Thereby, there are few restrictions on an installation place and it can be used for a wide use. For example, when it is used by being attached to an article, it can be provided following the shape of the article. For example, as shown in FIG. 13, even when the communication disturbing member 12 is an article having a cylindrical outer surface, for example, a beverage container, it is possible to attach it in accordance with the shape of the surface. . Therefore, it is possible to reduce the restriction on the mounting place of the sheet body 10 and facilitate the mounting work. When used as the tag 30, it is possible to adhere to the surface of the cylindrical surface by appropriately selecting a material having another configuration and making the tag 30 have a flexible configuration as a whole. It becomes like this.

  In addition, since the sheet body 10 is provided with adhesiveness on at least one surface portion, when attached to an article, the sheet body 10 can be attached to the article using the adhesiveness. Thus, the sheet body 10 can be easily attached to the article. Therefore, the operation | work for utilizing the sheet | seat body 10 and an electronic information transmission apparatus provided with the same can be made easy.

  Further, the sheet body 10 has flame retardancy. An electronic information transmission apparatus that includes the tag 30 and performs wireless communication using the antenna element 11 may be required to have flame retardancy. The sheet body 10 can be suitably used for applications that require such flame retardancy.

  The environment in which the sheet body is used may be used in the vicinity of a means serving as a heat source, such as a communication means including an IC 17 and a power supply means. Due to the excellent thermal conductivity of the sheet body 10, the heat generated by the means serving as a heat source can be released, the temperature rise of the means serving as the heat source is suppressed, and the performance deteriorates due to exposure to high temperatures. Can be prevented.

The sheet body 10 has heat resistance and electrical insulation. With regard to heat resistance, it may be used at 120 ° C. and 130 ° C. particularly in automobile applications, and it is required that it can be used without deterioration in performance even at that temperature. The heat resistance can be realized by adding a crosslinking material and crosslinking the binder. The cross-linking means is not limited, but it is of course possible to realize heat resistance at a higher temperature (for example, 200 ° C.) by appropriately combining the type of the binder and the cross-linking material. Furthermore, by covering the soft magnetic metal powder with an organic and inorganic insulating material as a binder, the electrical insulation of the sheet body 10 can be improved without direct contact with the soft magnetic metal dispersed in the sheet. it can. If electricity is conducted, an eddy current is generated in itself and the magnetic energy is attenuated. Furthermore, since the circuit and the plated casing (ground) are arranged in close proximity, if the sheet body 10 is conductive, it will be conducted through it, which hinders operation. In order to prevent these, the sheet body 10 achieves a surface resistivity of 10 ² Ω / □ or more.

  FIG. 15 is a plan view schematically showing a tag 30 according to still another embodiment of the present invention. In this case, the antenna element 11 is formed of a substantially annular loop antenna, and the IC 17 is connected thereto. FIG. 16 is a cross-sectional view showing the tag 30 of FIG. The tag 30 shown in FIGS. 15 and 16 has a configuration similar to that of the tag 30 described with reference to FIGS. 1 to 14, and the same reference numerals are assigned to the corresponding configurations, and only different points will be described. In the tag 30 shown in FIGS. 15 and 16, a loop antenna is used as the antenna element 11 and is laminated on the base material 18. 15 and 16, the sheet body 10 includes only the shield layer 13, and the antenna element 11 is provided with the sheet body 10 (shield layer 13) via the base material 18.

  FIG. 15 and FIG. 16 show a state where two tags 30 are provided side by side in a direction perpendicular to the thickness direction while being in contact with each other. The two tags 30 shown in FIG. 15 have the same configuration, but for the purpose of helping understanding in the following description, FIG. 15 shows the subscript “a” in the antenna element 11 and the IC 17 of the left tag 30. ", And the antenna element 11 and the IC 17 of the tag 30 on the right side are indicated with a subscript" b ". If identification is necessary in the sentence, the subscript is used for identification. If it is unnecessary, it will be explained without using a subscript.

  As shown in FIGS. 15 and 16, the plurality of tags 30 are arranged close to each other, for example, a plurality of articles are provided in a dense state, and one tag 30 is attached to each of these articles. The state of the case. The article in this case is, for example, a test tube in which a sample is stored, and is stored in each region of the test tube stand having regions partitioned in a matrix. Each tag 30 is attached to each test tube or test tube lid.

  When a plurality of tags 30 are provided in a dense state in this way, the antenna element 11 of the other tag 30 becomes a communication disturbing member for one tag 30, but the sheet body 10 is provided for each tag 30. In addition, by providing the sheet body 10 in the vicinity of the antenna element 11, it is possible to prevent a communication failure from occurring in each tag 30. As described above, the sheet body 10 is not provided between the antenna element 11 and the communication disturbing member, here, the other antenna element 11, but if provided in the vicinity of the antenna element 11, the communication environment of the antenna element 11 is improved. Can be improved.

  FIG. 17 is a graph showing a simulation result when two tags 30 are arranged close to each other as shown in FIGS. 15 and 16. FIG. 18 is a graph showing a simulation result in a case where two tags not provided with the sheet body 10 are similarly arranged in the tag 30 shown in FIGS. 15 and 16. FIG. 17 is a graph showing the relationship between the frequency and the S parameter value. The unit of the S parameter value is dB, and the magnitudes of the values are relatively compared. Here, “S11” represents the ratio of the reflected power, and “S21” represents the power propagated between the antenna elements 11 (between the ICs 17). Specifically, “S11” is the power supplied to the IC 17a (or IC 17b) of the left side (or right side) tag 30 when two tags 30 are provided side by side as shown in FIG. Of these, the ratio of the power reflected by the IC 17a (or IC 17b) of the left (or right) tag 30 is represented, and “S21” is supplied from the IC 17a (or IC 17b) of the left (or right) tag 30 Of the electric power, the ratio of the electric power transmitted to the IC 17b (or IC 17a) of the tag 30 on the right side (or left side) is represented. Such a state in which power is transmitted from one IC 17 to the other IC 17 is referred to as coupling in the present invention. In the case of FIG. 15, since the two tags 30 have the same configuration, S11 and S21 when power is supplied from the IC 17a of the left tag 30, and S11 and S21 when power is supplied from the IC 17b of the right tag 30 , The same value. “Single coil S11” represents a value corresponding to “S11” when the tag 30 as shown in FIG.

  Table 2 shows the material constants of each layer set in the simulation. Each material constant is a value at a frequency of 2.4 GHz.

  In this simulation, the coupling characteristics between the antenna elements 11 of the two loop antennas existing in the vicinity are evaluated using the sheet body 10 of the present invention. In the simulation, the shield layer 13 was prepared by adding carbonyl iron 530 (parts) to chlorinated polyethylene 100 (parts) and kneading them into a sheet. This shield layer 13 has a material constant measured by a coaxial tube method of 2.431, the real part ε ′ of the complex relative permittivity is 12.31, the permittivity loss term tan δε = 0.07, and the complex relative permeability. The real part μ ′ was 3.0 and the permeability loss term tan δμ = 0.43. This material constant was used in the simulation.

  As shown in FIG. 18, in the absence of the sheet body 10, when the two antenna elements 11 are arranged close to each other, the parabolas of S11 and S21 have a bimodal shape and have peaks before and after the original communication frequency. The communication characteristics at the communication frequency deteriorate. It is an example of the loss of communication electromagnetic energy. This is due to the coupling between the antenna elements 11. On the other hand, as shown in FIG. 17, when the sheet bodies 10 are laminated, the bimodality disappears and the communication characteristics are improved. Although this mechanism is only speculative, it can be considered that the electromagnetic wave radiation pattern is changed by the sheet member 10, the antenna operation is changed by shortening the wavelength by the shield layer, and the influence is caused by the loss component of the shield layer. In any case, it is clear that the communication environment is improved by the sheet body 10.

  As described above, the two antenna elements 11 (tags 30) existing in the vicinity are modeled on the reading of the dense tag 30 (trans bonder), and the antenna elements 11 of each other serve as communication obstructing members. In particular, there are concerns about the effects of binding. It has been found that there is a possibility that the coupling between the antenna elements 11 can be relaxed by laminating the sheet body 10 of the present invention on the antenna element 11. In the present example, the sheet body 10 is not disposed between the antenna element 11 and the communication disturbing member, but is disposed in the vicinity of the antenna element 11.

  15 to 18 show an example in which two tags 30 are arranged. However, even if electronic information transmission devices such as card-type transponders are stacked, the communication environment is the same as described above. Improved.

  The above-described embodiment is merely an example of the present invention, and the configuration can be changed. For example, the stacked configuration may be changed. Specifically, the structure by which the other adhesive agent layer which has the structure similar to the adhesive agent layer 15 on the opposite side to the conductor layer 14 grade | etc., With respect to the shield layer 13 may be provided. When such a sheet body 10 is used for the tag 30, when the sheet body 10 is attached to the tag main body 33 on which the antenna element 11 and the IC 17 are mounted to configure the tag 30, a separate adhesive is used. Even if it does not use, it becomes possible to stick using another sticking agent layer, and work becomes easy. In this way, the installation and installation work of the sheet body 10 can be facilitated, such as easy integration of the sheet body 10 into the electronic information transmission device.

  Moreover, the sticking agent layer 15 may be used for sticking the sheet body 10 to the tag main body 33 when the sticking agent layer 15 is incorporated into the tag 30. In this case, if the other adhesive layer is provided, the adhesive layer may be attached to the article using the other adhesive layer, and the other adhesive layer is not provided. For example, it may be attached to an article using an adhesive or an adhesive. Further, the adhesive layer 15 and the other adhesive layer are not essential components, and without forming these layers, an adhesive or an adhesive is added to a layer such as the shield layer 13 to form the sheet body 10. The structure which provides adhesiveness or adhesiveness to the surface of this may be sufficient.

  Further, the means for imparting flame retardancy may be another configuration instead of the configuration in which the flame retardant is added. Further, the minimum performance required for the sheet body 10 is a performance for blocking a magnetic field, and the other performance is not an essential requirement and may not have a configuration.

  The use of the sheet body 10 is not limited to the tag 30, and may be a transponder other than the tag 30, an electronic information transmission apparatus other than the transponder, or the antenna element 11 and the sheet body. 10 may be configured as an antenna device. Examples of the electronic information transmission device other than the tag 30 include an antenna, a reader, a reader / writer, a mobile phone device, a PDA, and a personal computer that construct an RFID system together with the tag 30, but other anti-theft devices, robots, etc. It may be any antenna functional component that uses communication such as remote control, on-vehicle ECU, and other radio technology using radio waves. As described above, the frequency is not limited to the radio wave range. Further, the use of the sheet body 10 is not limited to the electronic information transmission device, and can be widely used in applications where there is a requirement to at least block the magnetic field. The tag 30 may be an article having the communication disturbing member 12 other than the above-described article.

  When a conductive conductor layer is laminated on the sheet body 10, it can function as an antenna even when wireless communication is performed in the vicinity of a member having a portion made of any conductive material by adjusting the resonance frequency of the antenna. Become. A known means can be used to adjust the resonance frequency of the antenna.

  Configuration changes other than these examples may be used.

It is sectional drawing which simplifies and shows the sheet | seat body 10 of one Embodiment of this invention. 3 is an enlarged cross-sectional view showing an internal structure of a shield layer 13. FIG. 4 is a graph showing measurement results of material constants μ ′, μ ″, ε ′, and ε ″ of Example 1. It is sectional drawing which simplifies and shows the tag 30 provided with the sheet | seat body. 2 is a perspective view showing a tag 30. FIG. 4 is a cross-sectional view showing an electric field formed in the vicinity of the antenna element 11 in a state where the tag 30 is stuck to the communication disturbing member 12. FIG. 3 is a cross-sectional view showing an electric field formed in the vicinity of the antenna element 11 in a state where the antenna element 11 and the IC tag 17 are arranged in the vicinity of the communication disturbing member 12 without the sheet body 10 interposed. It is sectional drawing which shows the structure of the tag 30 assumed in the simulation for confirming the effect of the sheet | seat body 10 when using a dipole antenna as the antenna element 11. FIG. It is a graph which shows the simulation result by the structure of FIG. 8, and shows the relationship between a frequency and the input impedance of an antenna element. It is a graph which shows the simulation result by the structure of FIG. 8, and shows a directivity gain. It is a graph which shows the simulation result by the structure of FIG. 8, and shows an absolute gain. It is a perspective view which simplifies and shows the tag 30 of other form of implementation of this invention. It is a perspective view which shows the beverage 40 with which the tag 30 is mounted | worn. It is a perspective view which shows the electronic device 41 in which the tag 30 is incorporated. It is a top view which simplifies and shows the tag 30 of other form of implementation of this invention. It is sectional drawing which shows the tag 30 of FIG. It is a graph which shows the simulation result in case two tags 30 are arrange | positioned adjacently like FIG. 15 and FIG. It is a graph which shows the simulation result in case the two tags which are not provided with the sheet | seat body 10 in the tag 30 shown in FIG. 15 and FIG. It is sectional drawing which simplifies and shows the tag 1 which is a prior art. It is sectional drawing which simplifies and shows the tag 1A which is another prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sheet body 11 Antenna element 12 Communication obstruction member 13 Shield layer 14 Conductor layer 15 Adhesive agent layer 17 IC
20 Binder 21 Magnetic Powder 22 Magnetic Fine Particle 30 Tag 37 Magnetic Field Line 40 Beverage 41 Electronic Device

Claims (21)

  When wireless communication is performed in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element, the antenna is provided between the antenna element and a member having a portion made of a conductive material or in the vicinity of the antenna element. The sheet | seat body provided with the structure which suppresses the fall of the input impedance of the antenna element by the member which has a part which consists of a conductive material.   When wireless communication is performed in the vicinity of a member having a portion made of a conductive material using an electric field type antenna element, the antenna is provided between the antenna element and a member having a portion made of a conductive material or in the vicinity of the antenna element. The sheet | seat body provided with the structure which suppresses the loss of the electromagnetic energy by the member which has a part which consists of an electroconductive material.   3. The sheet body according to claim 1, wherein the antenna element includes at least one of a dipole antenna, a monopole antenna, a loop antenna, or an antenna loaded with a reactance structure portion thereon.   The sheet body according to any one of claims 1 to 3, wherein the frequency of the electromagnetic wave used for wireless communication is included in a range of 300 MHz to 300 GHz.   The sheet body according to claim 4, wherein the frequency of the electromagnetic wave used for wireless communication is included in a range of 860 MHz to 1 GHz.   The sheet body according to claim 4, wherein the frequency of electromagnetic waves used for wireless communication is included in a 2.4 GHz band.   The sheet body according to claim 1, further comprising a shield layer that is a magnetic body.   8. The shield layer according to claim 1, wherein a real part μ ′ of the complex relative permeability is equal to or more than an imaginary part μ ″ of the complex relative permeability at the frequency of the electromagnetic wave used for wireless communication. The sheet | seat body as described in any one.   2. A shield layer having a real part μ ′ of a complex relative permeability of 5 or more and a permeability loss term tan δμ of 1 or less at a frequency of an electromagnetic wave used for wireless communication is provided. The sheet body according to any one of 8.   2. A shield layer having a real part μ ′ of complex relative permeability of 20 or more and a permeability loss term tan δμ of 0.5 or less at the frequency of electromagnetic waves used for wireless communication. The sheet | seat body as described in any one of -8.   The sheet body according to any one of claims 1 to 10, further comprising a shield layer having a real part ε 'of a complex relative dielectric constant of 20 or more at a frequency of an electromagnetic wave used for wireless communication.   The sheet body according to claim 1, further comprising a shield layer having an imaginary part ε ″ of a complex relative dielectric constant of 300 or less at a frequency of an electromagnetic wave used for wireless communication.   It has a conductor layer which has conductivity, The sheet object according to any one of claims 1 to 12 characterized by things.   The shield layer is made of a material comprising at least one of a soft magnetic metal, a soft magnetic metal oxide, a magnetic metal and a magnetic metal oxide, or a material containing the same as the magnetic material. The sheet | seat body as described in any one of 1-13.   The shield layer contains, as a magnetic material, one or more materials selected from the group of ferrite, iron alloy, and iron particles in an amount of 1 part by weight or more and 1500 parts by weight or less with respect to 100 parts by weight of the organic polymer. It consists of material, The sheet | seat body as described in any one of Claims 1-14 characterized by the above-mentioned.   The sheet body according to any one of claims 1 to 15, wherein flame retardancy is imparted.   Thermal conductivity is given, The sheet object as described in any one of Claims 1-16 characterized by the above-mentioned.   At least one surface part has adhesiveness or adhesiveness, The sheet | seat body as described in any one of Claims 1-17 characterized by the above-mentioned. An electric field antenna element having a resonance frequency matched to a frequency used for wireless communication;
An antenna device comprising: the sheet body according to claim 1.   An electronic information transmission device comprising the antenna device according to claim 19.   21. The electronic information transmission apparatus according to claim 20, wherein the electronic information transmission apparatus is used as a transponder mounted on a densely packed article.

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