Wireless communication equipment

Abstract

The object is to provide a wireless communication device that can prevent the risk of fire in a product with the wireless communication device even when the product with the wireless communication device is irradiated with electromagnetic waves of a frequency band higher than a predetermined communication frequency. A wireless communication device (1) for transmitting and receiving high-frequency signals having a predetermined communication frequency comprises: an antenna pattern (3) having an inductance component; an RFIC package (2) electrically connected to the antenna pattern (3); and a capacitive coupling unit (4) that capacitively couples specific facing regions (3aa) of the antenna pattern (3) facing each other at a plurality of locations of the antenna pattern (3) to form an LC parallel resonant circuit (S).

Description

[0001] This application is a divisional application of the Chinese invention patent application with application date of April 20, 2018, application number 201880002477.X, and invention name “Wireless Communication Device”. Technical Field

[0002] The present invention relates to a wireless communication device having an antenna, and more particularly to a wireless communication device using RFID (Radio Frequency Identification) technology for contactlessly reading and writing data in a semiconductor memory by performing short-range communication using an inductive electromagnetic field or radio waves. Background Art

[0003] Considering the automation of commodity settlement by attaching an "RFID tag" as a wireless communication device to commodities, according to this automated checkout system, when a basket containing commodities with "RFID tags" is placed at a checkout counter, information from the "RFID tags" is read to display the commodity price.

[0004] In supermarkets and other stores, a wide variety of goods are traded. Among the food products, the goods are sometimes heated shortly after purchase and eaten immediately on the spot. Examples of goods that are eaten after being heated in this way include boxed lunches, cup noodles, and the like. It is believed that these goods are heated by electromagnetic wave heating devices, so-called "microwave ovens", in stores.

[0005] In an "RFID tag", a metal material such as an antenna pattern as a metal film body is formed on a paper material or a resin material together with an RFIC (Radio-Frequency Integrated Circuit) chip. Therefore, when a product with such an "RFID tag" is heated in a "microwave oven", for example, when a lunch box with an "RFID tag" is heated, there is a concern that the "RFID tag" and the lunch box absorb electromagnetic waves from the "microwave oven", the electric field is concentrated at the metal material part and discharged, or the metal itself is heated and sublimated due to an overcurrent flowing through the metal material part, or the paper material or resin material constituting the tag catches fire, thereby catching fire of the "RFID tag".

[0006] For the purpose of reducing the risk of fire in the above-mentioned “RFID tag”, a structure of a “flame-retardant tag” has been proposed (see Patent Document 1).

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-338563 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The "flame-retardant label" disclosed in Patent Document 1 is a substrate for mounting an IC chip and an antenna pattern, which is made of a flame-retardant material. Therefore, since the substrate is a flame-retardant material, it will be extinguished within a few seconds to tens of seconds after ignition. However, there is a high possibility of continuous discharge at the metal material portion formed on the substrate, and it is not a structure that can reliably prevent the danger of substrate ignition or the possibility of product ignition.

[0010] An object of the present invention is to provide a wireless communication device capable of preventing the risk of fire in a product with the wireless communication device even when the product with the wireless communication device is irradiated with electromagnetic waves of a frequency band higher than a predetermined communication frequency.

[0011] Solutions for solving problems

[0012] A wireless communication device according to one embodiment of the present invention is used to transmit and receive a high-frequency signal having a predetermined communication frequency, and the wireless communication device comprises:

[0013] an antenna pattern having an inductive component;

[0014] an RFIC element electrically connected to the antenna pattern; and

[0015] The capacitive coupling unit capacitively couples specific opposing regions of the antenna patterns that face each other at a plurality of locations in the antenna pattern to form an LC parallel resonant circuit.

[0016] Effects of the Invention

[0017] According to the present invention, it is possible to provide a wireless communication device capable of preventing the risk of fire in a product even when the product with the wireless communication device is irradiated with electromagnetic waves of a frequency band higher than a predetermined communication frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a plan view showing the wireless communication device (RFID tag) according to the first embodiment.

[0019] Figure 2A This is a diagram showing the surface (first main surface) of the antenna substrate in the wireless communication device according to the first embodiment.

[0020] Figure 2B This is a diagram showing the back surface (second main surface) of the antenna substrate in the wireless communication device according to the first embodiment.

[0021] Figure 3A This is a diagram showing an example of a product with a wireless communication device according to Embodiment 1.

[0022] Figure 3B This is a diagram showing an example of a product with a wireless communication device according to Embodiment 1.

[0023] Figure 4 This is an exploded perspective view showing the RFIC package in the wireless communication device according to the first embodiment.

[0024] Figure 5 This is a diagram schematically showing a capacitive coupling portion for an antenna pattern in the wireless communication device according to the first embodiment using circuit diagram symbols.

[0025] Figure 6 This is a pseudo equivalent circuit diagram showing a partial configuration of a plurality of LC parallel resonant circuits in the wireless communication device according to the first embodiment.

[0026] Figure 7 This is an equivalent circuit diagram showing an overall configuration example of a plurality of LC parallel resonant circuits in the wireless communication device according to the first embodiment.

[0027] Figure 8 This is a frequency characteristic diagram showing the results of a simulation experiment in the wireless communication device according to the first embodiment.

[0028] Fig. 9 This is a Smith chart obtained in a simulation experiment related to the wireless communication device according to the first embodiment.

[0029] Fig. 10A This is a diagram showing the flow of current when a signal of a communication frequency (920 MHz) in the UHF band is received in the wireless communication device according to the first embodiment.

[0030] Fig. 10B This is a diagram showing the flow of electric current when a signal of a heating frequency (2.4 GHz) used by an electromagnetic wave heating device (“microwave oven”) is received in the wireless communication device according to the first embodiment.

[0031] Fig.11 This is a diagram showing the direction in which a current attempts to flow when the antenna pattern and the capacitive coupling portion (line capacitance pattern) receive a signal having a heating frequency in the wireless communication device according to the first embodiment.

[0032] Fig. 12A This is a diagram showing gains for all directions related to the wireless communication device according to Embodiment 1.

[0033] Fig. 12B This is a diagram showing the gain of the wireless communication device according to Embodiment 1.

[0034] Fig.13 It is a top view showing the structure of a wireless communication device (RFID tag) according to the second embodiment.

[0035] Fig.14 It is a top view showing the structure of a wireless communication device (RFID tag) according to the third embodiment.

[0036] Fig.15 It is a top view showing a modified example of the wireless communication device according to the third embodiment.

[0037] Fig.16A It is a top view showing the structure of a wireless communication device (RFID tag) according to a fourth embodiment.

[0038] Fig. 16B This is an equivalent circuit diagram showing the structure of an antenna pattern in a wireless communication device according to a fourth embodiment.

[0039] Fig.17A It is a top view showing the structure of a wireless communication device (RFID tag) according to the fifth embodiment.

[0040] Fig. 17B This is an equivalent circuit diagram showing the structure of an antenna pattern in a wireless communication device according to the fifth embodiment.

[0041] Fig.18 It is a top view showing the structure of a wireless communication device (RFID tag) according to the sixth embodiment.

[0042] Fig.19A It is a top view showing the structure of a wireless communication device (RFID tag) according to the sixth embodiment.

[0043] Fig.19B This is an equivalent circuit diagram of a part of the structure of the antenna pattern in the wireless communication device according to the sixth embodiment.

[0044] Fig.19C This is an explanatory diagram showing a current flowing through a part of an antenna pattern in a wireless communication device according to a sixth embodiment.

[0045] Fig. 20 It is a top view showing the structure of a wireless communication device (RFID tag) according to the seventh embodiment.

[0046] Fig.21 It is a top view showing the structure of a wireless communication device (RFID tag) according to the eighth embodiment.

[0047] Fig. 22 It is a top view showing the structure of a wireless communication device (RFID tag) according to the ninth embodiment.

[0048] Fig.23 It is a top view showing the structure of a wireless communication device (RFID tag) according to the tenth embodiment.

[0049] Fig.24 It is a disassembled stereoscopic diagram showing the structure of a wireless communication device (RFID tag) according to embodiment 11.

[0050] Fig.25 It is a top view showing the structure of a wireless communication device (RFID tag) according to embodiment 12.

[0051] Fig.26 This is a top view of the wireless communication device (RFID tag) of embodiment 12 when it is installed on a product.

[0052] Fig. 27 This is a diagram showing an example of a product with a wireless communication device according to embodiment 12.

[0053] Fig.28 It is a frequency characteristic diagram showing the results of a simulation experiment in the wireless communication device according to the sixth embodiment.

[0054] Fig.29 This is a Smith chart obtained in a simulation experiment related to the wireless communication device according to the sixth embodiment.

[0055] Fig. 30A This is a diagram showing how current flows when a signal at a communication frequency (920 MHz) in the UHF band is received in the wireless communication device according to the sixth embodiment.

[0056] Fig. 30B This is a diagram showing the flow of electric current when a signal of a heating frequency (2.4 GHz) used by an electromagnetic wave heating device (“microwave oven”) is received in the wireless communication device of the sixth embodiment.

[0057] Fig.31A This is a diagram showing gains for all directions related to the wireless communication device of Embodiment 6.

[0058] Fig.31B It is related to the wireless communication device of Embodiment 6, Fig. 12A Plot of the gain on the XZ plane.

[0059] Fig.32 It is a top view showing the structure of a wireless communication device (RFID tag) according to embodiment 13.

[0060] Fig.33 This is a top view showing a modified example of the wireless communication device according to embodiment 13.

[0061] Fig.34A This is a top view of the wireless communication device (RFID tag) of embodiment 14 when it is installed on a product.

[0062] Fig.34BThis is an equivalent circuit diagram showing the structure of an antenna pattern in a wireless communication device according to a fourteenth embodiment.

[0063] Fig.35A This is a top view of the wireless communication device (RFID tag) of embodiment 15 when installed on a product.

[0064] Fig.35B This is an equivalent circuit diagram showing the structure of an antenna pattern in a wireless communication device according to Embodiment 15.

[0065] Fig.36 This is a top view of a wireless communication device (RFID tag) according to embodiment 16. DETAILED DESCRIPTION

[0066] First, the configurations of various modes of the wireless communication device according to the present invention will be described.

[0067] A wireless communication device according to a first aspect of the present invention is a wireless communication device for transmitting and receiving a high-frequency signal having a predetermined communication frequency, the wireless communication device comprising:

[0068] an antenna pattern having an inductive component;

[0069] an RFIC element electrically connected to the antenna pattern; and

[0070] The capacitive coupling unit capacitively couples specific opposing regions of the antenna patterns that face each other at a plurality of locations in the antenna pattern to form an LC parallel resonant circuit.

[0071] Regarding the wireless communication device of the first mode constructed as described above, even when the product with the wireless communication device is irradiated with electromagnetic waves of a bandwidth with a frequency higher than the communication frequency, the occurrence of discharge in the wireless communication device can be suppressed, thereby preventing the risk of fire in the product with the wireless communication device.

[0072] In addition, the antenna pattern can be either a straight line or a curve. For a continuous antenna pattern having respective opposing regions, it is sufficient as long as the antenna pattern of the other side exists in a direction intersecting with the direction in which the antenna pattern of one side extends. Therefore, the opposing regions existing in the continuous antenna pattern include the case where they are located parallel to each other and the case where either side is inclined, and the curves can also face each other.

[0073] In the wireless communication device of the second aspect of the present invention, the antenna pattern may be formed in a meandering shape having a plurality of folded portions, and the capacitive coupling portion constituting the LC parallel resonant circuit may be configured to capacitively couple adjacent folded portions in the antenna pattern.

[0074] In the wireless communication device according to the third aspect of the present invention, the antenna pattern may be provided on one surface of an antenna substrate made of a dielectric, and the capacitive coupling unit may be provided on the other surface of the antenna substrate.

[0075] In the wireless communication device of the fourth aspect of the present invention, the antenna pattern and the capacitive coupling section may be provided on one surface of an antenna substrate, and the capacitive coupling section may be a conductor plate disposed between the specific opposing regions facing each other.

[0076] In the wireless communication device according to the fifth aspect of the present invention, the antenna pattern and the capacitive coupling unit may be stacked on one surface of an antenna substrate, and a dielectric may be interposed between the antenna pattern and the capacitive coupling unit.

[0077] In the wireless communication device according to the sixth aspect of the present invention, a line length of the LC parallel resonant circuit may be formed to be shorter than 1 / 2 wavelength of the predetermined communication frequency.

[0078] In the wireless communication device of the seventh aspect of the present invention, the line length of the LC parallel resonant circuit may be formed to be shorter than 1 / 2 wavelength of a frequency used in electromagnetic wave heating.

[0079] In the wireless communication device according to the eighth aspect of the present invention, the LC parallel resonant circuit may have a resonant frequency higher than the predetermined communication frequency.

[0080] The wireless communication device according to the ninth aspect of the present invention may be configured such that the LC parallel resonant circuit has a frequency used in electromagnetic wave heating as a resonant frequency.

[0081] The wireless communication device of the tenth aspect of the present invention may be configured such that the LC parallel resonant circuit has a resonant frequency in a frequency bandwidth of 2.4 GHz to 2.5 GHz, which is a frequency bandwidth used in electromagnetic wave heating.

[0082] In the wireless communication device according to the eleventh aspect of the present invention, the antenna pattern may have a line width narrower than a line width of the capacitive coupling unit.

[0083] In the wireless communication device of the twelfth aspect of the present invention, the antenna pattern may be formed in a meandering shape having a plurality of folded portions, and the length of the antenna pattern in the amplitude direction of the meandering may be longer than the length of the capacitive coupling portion.

[0084] A wireless communication device according to a thirteenth aspect of the present invention may include a resin antenna substrate on which the antenna pattern is formed.

[0085] The wireless communication device of the fourteenth aspect according to the present invention may include a film attached to the resin antenna base, wherein the film has higher heat resistance than the antenna base.

[0086] In the wireless communication device of the fifteenth aspect according to the present invention, the antenna pattern may be formed of a dipole antenna having two dipole elements, and the capacitive coupling portion constituting the LC parallel resonant circuit may be provided in each of the dipole elements.

[0087] In the wireless communication device of the sixteenth aspect according to the present invention, a part of the current path of the antenna pattern constituting the LC parallel resonant circuit may be formed thinner than other parts of the current path.

[0088] In the wireless communication device of the seventeenth aspect according to the present invention, a portion of a current path of the antenna pattern constituting the LC parallel resonant circuit may be formed thinner than other portions of the current path.

[0089] In the wireless communication device according to the eighteenth aspect of the present invention, the antenna pattern may be configured to use the UHF band as a communication frequency.

[0090] In the wireless communication device of the nineteenth aspect according to the present invention, the antenna pattern may be configured to use the HF band as a communication frequency.

[0091] In the wireless communication device according to the twentieth aspect of the present invention, a resonance frequency obtained by the antenna pattern when the capacitive coupling unit is not present may be higher than the communication frequency.

[0092] The wireless communication device of the 21st mode involved in the present invention is used to send and receive high-frequency signals having a frequency for communication, and the wireless communication device comprises: an antenna pattern, which has opposing areas facing each other; an RFIC chip, which is electrically connected to the antenna pattern; and a ring-shaped conductor pattern, which is arranged between each opposing area of ​​the antenna pattern, wherein the circumference of the conductor pattern is less than half the wavelength of the frequency for communication.

[0093] Regarding the wireless communication device of the 21st mode constructed as described above, when the commodity with the wireless communication device is irradiated with electromagnetic waves of a bandwidth with a frequency higher than the communication frequency, the ring-shaped conductor pattern generates a magnetic field as a magnetic field antenna. As a result, a magnetic field antenna is formed at a position close to the antenna pattern that receives electromagnetic waves of a bandwidth with a frequency higher than the communication frequency. As a result, the antenna radiation efficiency of the antenna pattern in a frequency band higher than the communication frequency becomes worse, and the energy received by the antenna pattern can be reduced. As a result, the risk of fire in the commodity with the wireless communication device can be prevented.

[0094] In the wireless communication device of the twenty-second aspect according to the present invention, the antenna pattern may be formed in a meandering shape, and each of the facing regions of the antenna pattern may have straight line portions parallel to each other.

[0095] In the wireless communication device of the twenty-third aspect according to the present invention, the conductor pattern may be arranged between adjacent folded portions of the antenna pattern.

[0096] The wireless communication device of the 24th aspect of the present invention may be such that: the conductor pattern has a long side direction and a short side direction, and the length of the conductor pattern in the long side direction is formed to be less than 1 / 4 wavelength of a frequency used in electromagnetic wave heating.

[0097] In the wireless communication device of the twenty-fifth aspect according to the present invention, a plurality of the conductor patterns may be arranged between the respective opposing regions of the antenna pattern so as to be spaced apart from each other.

[0098] The wireless communication device of the 26th mode involved in the present invention may also be: when the antenna pattern is irradiated with electromagnetic waves of a frequency higher than the communication frequency, the potential difference between each of the opposing areas of the antenna pattern between the plurality of conductor patterns becomes larger.

[0099] The wireless communication device of the twenty-seventh aspect of the present invention may be configured such that: the conductor patterns having different circumferences are arranged along a straight line portion of the antenna pattern.

[0100] The wireless communication device of the 28th mode involved in the present invention may also be: a first resonant frequency obtained by the conductor pattern and a part of the antenna pattern including the opposing area sandwiched between the conductor patterns is different from a second resonant frequency obtained by another conductor pattern arranged next to the conductor pattern and another part of the antenna pattern including the opposing area sandwiched between the other conductor pattern.

[0101] The wireless communication device according to the twenty-ninth aspect of the present invention may be configured such that: the first resonance frequency is a frequency used in electromagnetic wave heating.

[0102] The wireless communication device of the 30th aspect of the present invention may be: the first resonant frequency has a frequency in a bandwidth of 2.4 GHz to 2.5 GHz as the resonant frequency, and the bandwidth of 2.4 GHz to 2.5 GHz is the frequency bandwidth used in electromagnetic wave heating.

[0103] The wireless communication device of the 31st mode involved in the present invention may also be: the difference between the circumference of the conductor pattern and 1 / 2 wavelength of the first resonant frequency higher than the frequency used for communication is smaller than the difference between the circumference of the conductor pattern and 1 / 2 wavelength of the frequency used for communication.

[0104] Convenience stores and supermarkets that sell products equipped with wireless communication devices conduct transactions for a wide variety of products, including food and daily groceries. In recent years, various experiments have been conducted on the practical application of "unmanned convenience stores" in which the settlement and bagging of purchased products are automated.

[0105] In order to automate the settlement of goods in "unmanned convenience stores", the idea is to attach "RFID tags" as wireless communication devices to all goods. In "unmanned convenience stores", the following system is used: when a shopping basket containing goods with "RFID tags" is placed at the checkout counter, the information from the "RFID tags" is read to display the price of the goods. Buyers can pay for the goods by inserting cash or credit cards at a specified location, and receive the goods automatically put in the shopping bag, thus completing the purchase of goods in the "unmanned convenience store".

[0106] Hereinafter, an embodiment of the wireless communication device according to the present invention will be described with reference to the accompanying drawings. In addition, as a commodity with a wireless communication device, i.e., an "RFID tag", according to the following embodiment, a lunch box is used as an example for description, but as a commodity with a wireless communication device according to the present invention, all commodities traded in so-called "convenience stores" and the like are the objects. The present invention relates to a commodity sales system in which a wireless communication device having the same structure is attached to all commodities.

[0107] In addition, the electromagnetic wave heating device described in the following embodiment is described using a so-called "microwave oven" that performs dielectric heating. However, the electromagnetic wave heating device in the present invention is a heating device having a function of performing dielectric heating.

[0108] Implementation Method 1

[0109] Figure 1: This is a top view of an RFID tag 1 which is a wireless communication device according to Embodiment 1 of the present invention. The RFID tag 1 is configured to perform wireless communication (transmission and reception) using a high-frequency signal having a communication frequency (carrier frequency) in the UHF band, and is a structure capable of wireless communication in a wide frequency band. Here, the UHF band refers to a band of 860 MHz to 960 MHz. Here, the communication frequency in the UHF band is an example of the "first frequency for communication" in the present invention. The RFID tag 1 includes an RFIC package 2 described later, an antenna pattern 3, an inter-wire capacitance pattern 4 as a capacitive coupling portion, and an antenna substrate 5 as a dielectric. In the RFID tag 1 of Embodiment 1, as the antenna substrate 5, a flame-retardant film material having flexibility is used, and is formed into a roughly rectangular shape. In addition, in the case where the antenna substrate 5 is not a flame-retardant film material, the film thickness of the antenna substrate 5 can also be made thinner than 38 μm. As a result, the antenna substrate 5 melts and deforms before burning, so that the substrate shape can be not maintained. The line width of the antenna pattern 3 is 100 μm to 300 μm. In particular, by making the line width of the antenna pattern 3 less than 150 μm, the antenna pattern 3 can be easily disconnected at the same time when the antenna substrate 5 is deformed. The antenna pattern 3 made of a film of a conductive material such as aluminum foil or copper foil is formed on the surface (first main surface) of the antenna substrate 5. In addition, the RFIC package 2 is installed on the antenna pattern 3 formed on the surface (first main surface) of the antenna substrate 5, and the RFIC package 2 is electrically connected to the antenna pattern 3. In addition, electrical connection means connection or coupling with each other so that high-frequency signals can be transmitted and operated, and is not limited to DC connection.

[0110] In addition, as a flame-retardant film material used as the antenna substrate 5 of Embodiment 1, for example, a film obtained by adding a halogen-based flame-retardant material to a resin material such as PET (polyethylene terephthalate) resin or PPS (polyphenylene sulfide) resin and applying a flame-retardant coating material is used. In addition, as a material for the antenna substrate 5, a high-performance resin material such as a heat-resistant PEN (polyethylene naphthalate) resin can also be used. In addition, the following structure can also be set: a film body of a heat-resistant material is also provided for the antenna substrate 5 as a dielectric, so as to further improve the heat resistance of the antenna substrate 5 as between the antenna pattern 3 and the line capacitance pattern 4.

[0111] On the other hand, an inter-line capacitance pattern 4 made of a conductive material such as aluminum foil or copper foil is formed on the back side (second main surface) of the antenna substrate 5 as a capacitance coupling portion. The inter-line capacitance pattern 4 formed on the back side (second main surface) of the antenna substrate 5 capacitively couples specific areas of the antenna pattern 3 at multiple locations of the antenna pattern 3 having an inductance component. As a result, an inductance component formed by a portion of the antenna pattern 3 and a capacitance component formed between a portion of the antenna pattern 3 and the inter-line capacitance pattern 4 constitute an LC parallel resonant circuit S, resulting in the following structure: a plurality of LC parallel resonant circuits S are formed, and the plurality of LC parallel resonant circuits S are substantially connected in series and in parallel. In addition, in Figure 1 , an example of using a transparent material as an antenna substrate 5 is shown, and an antenna pattern 3 and an inter-line capacitor pattern 4 (in Figure 1 In addition, as the antenna substrate 5, it is not necessary to use a transparent material, as long as it is a material that can at least achieve capacitive coupling with a desired capacitance between the antenna pattern 3 and the line capacitance pattern 4.

[0112] Figure 2A and Figure 2B The front surface (first main surface) and the back surface (second main surface) of the antenna substrate 5 are shown. Figure 2A The antenna pattern 3 formed on the surface (first main surface) of the antenna substrate 5 is shown. Figure 2B The figure shows the line capacitance pattern 4 as a capacitance coupling portion formed on the back surface (second main surface) of the antenna substrate 5 .

[0113] like Figure 2A As shown, in the antenna pattern 3 of Embodiment 1, two land patterns 6 (6a, 6b) are provided for contacting the RFIC package 2 to be electrically connected to the RFIC package 2. In addition, the antenna pattern 3 has a first antenna element 3a and a second antenna element 3b, forming a dipole type electric field antenna.

[0114] like Figure 2A As shown, the first antenna element 3a has a substantially linear shape pattern, and is extended in a meandering manner after being led out from the first land pattern 6a. The extension direction of the first land pattern 6a is toward one end in the long side direction of the antenna substrate 5, and the terminal end of the extension direction of the first land pattern 6a is arranged at the end in the long side direction of the antenna substrate 5. The first antenna element 3a has a length of λ / 4 of the communication frequency. For example, when the communication frequency is 920MHz, the length of the first antenna element 3a from the first land pattern 6a to the end of the antenna substrate 5 is about 80mm.

[0115] The second antenna element 3b of the antenna pattern 3 is led out from the second land pattern 6b and extends in a meandering manner toward the other end in the long side direction of the antenna substrate 5, and a wide portion 7 is formed at the terminal portion in the extending direction of the second antenna element 3b. The wide portion 7 is a portion to be attached to a product, and when attached to a product with metal material exposed on the outer surface of the product, such as a canned product, the wide portion 7 enables the outer surface of the product to function as a part of the antenna.

[0116] like Figure 2B As shown, in the structure of Embodiment 1, the inter-wire capacitance pattern 4 as a capacitance coupling portion formed on the back side (second main surface) of the antenna substrate 5 has a plurality of inter-wire capacitance electrodes 4a and 4b of different shapes. The inter-wire capacitance pattern 4 has a first inter-wire capacitance electrode 4a of a wide shape and a second inter-wire capacitance electrode 4b of a narrow shape. The first inter-wire capacitance electrode 4a of a wide shape performs capacitance coupling between specific opposing regions 3aa in the meandering first antenna element 3a, and similarly performs capacitance coupling between specific opposing regions 3ba in the meandering second antenna element 3b. The first inter-wire capacitance electrode 4a is arranged to perform capacitance coupling between at least the adjacent folded portions in the first antenna element 3a and the second antenna element 3b.

[0117] On the other hand, the narrow second inter-line capacitor electrode 4b is configured to capacitively couple a specific area in the first antenna element 3a with a specific area in the second antenna element 3b. In addition, the narrow second inter-line capacitor electrode 4b is configured to capacitively couple the first pad pattern 6a with a specific area in the first antenna element 3a, and is also configured to capacitively couple the second pad pattern 6b with a specific area (including the wide portion 7) in the second antenna element 3b.

[0118] In the antenna pattern 3 formed on the surface (first main surface) of the antenna substrate 5 and the line-to-line capacitance pattern 4 formed on the back surface (second main surface) of the antenna substrate 5 constructed as described above, they have a shape that prevents the concentration of the electric field, especially at the edge portions of the bent portions and the peripheral portions, where there are no sharp angles and all are composed of gently curved surfaces.

[0119] In addition, the RFID tag 1 of the first embodiment is used for all commodities traded in a "convenience store", for example, and the RFID tag 1 of the same structure is used for all commodities. Therefore, as an example of commodities in the first embodiment, a lunch box heated by a "microwave oven" as an electromagnetic wave heating device is used for description. For this lunch box, an RFID tag 1 having a wide portion 7 that allows the metal material on the outer surface of the commodity to function as a part of the antenna is also used. Figure 3A It is a perspective view showing a state where the RFID tag 1 is attached to a lunch box 8 as an example of a product made of an insulating material. Figure 3B An example is shown in which the RFID tag 1 is attached to a metal can 14 as an example of a commodity whose outer surface is made of a metal material.

[0120] Figure 4 2 is an exploded perspective view showing the structure of the RFIC package 2 mounted on the pad pattern 6 (6a, 6b) of the antenna pattern 3. Figure 4 As shown, the RFIC package 2 of the first embodiment is composed of a multilayer substrate including three layers. Specifically, the multilayer substrate of the RFIC package 2 is made of a resin material such as polyimide and liquid crystal polymer, and is composed of three flexible insulating sheets 12A, 12B, and 12C stacked. The insulating sheets 12A, 12B, and 12C are roughly square in shape when viewed from above, and have a roughly rectangular shape in the first embodiment. Figure 4 The RFIC package 2 shown shows the Figure 1 The RFIC package 2 shown is turned over and the three layers are disassembled.

[0121] like Figure 4 As shown, the RFIC package 2 has an RFIC chip 9, a plurality of inductance elements 10A, 10B, 10C, 10D, and external connection terminals 11 (11a, 11b) connected to the antenna pattern 3 formed at desired positions on a three-layer substrate (insulating sheets 12A, 12B, 12C).

[0122] The external connection terminals 11 (11a, 11b) are formed on the first insulating sheet 12A, which is the bottom layer (the substrate facing the antenna pattern 3), and are formed at positions facing the pad patterns 6 (6a, 6b) of the antenna pattern 3. The four inductance elements 10A, 10B, 10C, and 10D are formed separately on the second insulating sheet 12B and the third insulating sheet 12C so that two inductance elements are provided in each insulating sheet. That is, in the top layer (the substrate facing the antenna pattern 3), the external connection terminals 11 (11a, 11b) are formed on the first insulating sheet 12A, which is the bottom layer (the substrate facing the antenna pattern 3), and are formed at positions facing the pad patterns 6 (6a, 6b) of the antenna pattern 3. Figure 4 The first inductor element 10A and the second inductor element 10B are formed on the third insulating sheet 12C (described as the lowermost layer in FIG), and the third inductor element 10C and the fourth inductor element 10D are formed on the second insulating sheet 12B serving as an intermediate layer.

[0123] In the RFIC package 2 of the first embodiment, the external connection terminals 11 ( 11 a , 11 b ) and the four inductance elements 10A, 10B, 10C, and 10D are formed of a conductor pattern made of a conductive material such as aluminum foil or copper foil.

[0124] like Figure 4 As shown, the RFIC chip 9 is mounted on the third insulating sheet 12C as the uppermost layer, and the longitudinal direction ( Figure 4The RFIC chip 9 has a structure in which various elements are built into a semiconductor substrate made of semiconductors such as silicon. Figure 4 The first inductor element 10A formed in a spiral shape (in the left side in the X-axis direction) is connected to one input / output terminal 9a of the RFIC chip 9 via a pad 10Aa. Figure 4 The second inductance element 10B formed in a spiral shape (in the center, right side in the X-axis direction) is connected to the other input / output terminal 9b of the RFIC chip 9 via a pad 10Ba.

[0125] On one side (at the Figure 4 A spiral third inductor element 10C is formed on the other side (in the left side in the X-axis direction) of the second insulating sheet 12B. Figure 4 A spiral fourth inductor element 10D is formed (right side in the X-axis direction). The outer peripheral end of the spiral third inductor element 10C is directly connected to the outer peripheral end of the spiral fourth inductor element 10D. On the other hand, the inner peripheral end (pad 10Ca) of the third inductor element 10C is connected to the inner peripheral end (pad 10Ab) of the spiral first inductor element 10A on the third insulating sheet 12C via an interlayer connecting conductor such as a through-hole conductor penetrating the second insulating sheet 12B. In addition, the inner peripheral end (pad 10Ca) of the third inductor element 10C is connected to the first external connection terminal 11a on the first insulating sheet 12A via an interlayer connecting conductor such as a through-hole conductor penetrating the first insulating sheet 12A as the bottom layer.

[0126] The inner peripheral end (pad 10Da) of the fourth inductor element 10D is connected to the inner peripheral end (pad 10Bb) of the spiral second inductor element 10B on the third insulating sheet 12C via an interlayer connecting conductor such as a through-hole conductor penetrating the second insulating sheet 12B. In addition, the inner peripheral end (pad 10Da) of the fourth inductor element 10D is connected to the second external connection terminal 11b on the first insulating sheet 12A via an interlayer connecting conductor such as a through-hole conductor penetrating the first insulating sheet 12A as the lowermost layer.

[0127] The first external connection terminal 11a on the first insulating sheet 12A is arranged to be connected to the first land pattern 6a of the first antenna element 3a formed on the antenna substrate 5. In addition, the second external connection terminal 11b on the first insulating sheet 12A is arranged to be connected to the second land pattern 6b of the second antenna element 3b formed on the antenna substrate 5.

[0128] In addition, a through hole 13 for accommodating the RFIC chip 9 mounted on the third insulating sheet 12C is formed in the second insulating sheet 12B as an intermediate layer. The RFIC chip 9 is formed of a semiconductor material and is disposed between the first inductance element 10A and the second inductance element 10B and between the third inductance element 10C and the fourth inductance element 10D. Therefore, the RFIC chip 9 functions as a shield, so that the magnetic field coupling and capacitive coupling between the first inductance element 10A and the second inductance element 10B are suppressed, and similarly, the magnetic field coupling and capacitive coupling between the third inductance element 10C and the fourth inductance element 10D are suppressed. As a result, in the RFIC package 2 of the first embodiment, the passband of the communication signal is suppressed from being narrowed, and the passband is made wider.

[0129] Figure 5 FIG. 4 is a diagram schematically showing an inter-line capacitance pattern 4 using circuit diagram symbols. The inter-line capacitance pattern 4 is a capacitance coupling portion that performs capacitance coupling to the antenna pattern 3 connected to the RFIC package 2 in the RFID tag 1 of the first embodiment. Figure 5 As shown, the antenna pattern 3 is configured to extend from the pad pattern 6 on which the RFIC package 2 is mounted, and includes a first antenna element 3a and a second antenna element 3b that meander in a manner having a plurality of folded portions. That is, the first antenna element 3a in a meandering manner extends from the first pad pattern 6a in a manner that ultimately faces one end portion in the long side direction (+X direction) of the antenna substrate 5. In addition, the second antenna element 3b in a meandering manner extends from the second pad pattern 6b in a manner that ultimately faces the other end portion in the long side direction (-X direction) of the antenna substrate 5. In addition, the area of ​​the end portion in the extension direction of the second antenna element 3b is a wide portion 7 having a large width as a pasting portion to be pasted to a product, and this area is a region that is pasted to a metal portion of a canned product, for example, to further improve the characteristics as an antenna.

[0130] like Figure 5 As shown, the inter-wire capacitance pattern 4 that capacitively couples specific regions in the first antenna element 3a and the second antenna element 3b includes a first inter-wire capacitance electrode 4a having a large capacitance and a second inter-wire capacitance electrode 4b having a capacitance smaller than that of the first inter-wire capacitance electrode 4a. The first inter-wire capacitance electrode 4a capacitively couples specific regions in the first antenna element 3a, and forms a loop circuit as a minimum path formed by the first inter-wire capacitance electrode 4a and the first antenna element 3a as an LC parallel resonant circuit S. That is, a plurality of LC parallel resonant circuits S are formed in series and in parallel with the path of the first antenna element 3a. Similarly, the first inter-wire capacitance electrode 4a capacitively couples specific regions in the second antenna element 3b, and forms a plurality of LC parallel resonant circuits S in series and in parallel with the path of the second antenna element 3b.

[0131] As commodities to which the RFID tag 1 of the first embodiment is applied, for example, are lunch boxes in convenience stores, it is assumed that the RFID tag 1 is heated by a medium such as a so-called "microwave oven" which is an electromagnetic wave heating device for cooking. The electromagnetic waves (the operating frequency of microwaves) used in the "microwave oven" have a frequency bandwidth of 2.4 GHz to 2.5 GHz, which is a frequency bandwidth higher than the communication frequency. The RFID tag 1 of the first embodiment is provided with a "band rejection filter" as a circuit for significantly attenuating the level of this frequency band. The "band rejection filter" is a filter circuit that attenuates a frequency bandwidth higher than the communication frequency. In the RFID tag 1 of the first embodiment, for example, a frequency band higher than 1.1 GHz is attenuated. In particular, the frequency (2.4 GHz to 2.5 GHz) of the electromagnetic waves used for heating in the "microwave oven" is significantly attenuated.

[0132] like Figure 5 As shown, in the RFID tag 1 of Embodiment 1, a plurality of (multiple) LC parallel resonant circuits S are formed along the respective paths of the first antenna element 3a and the second antenna element 3b, and these LC parallel resonant circuits S constitute a "band-stop filter". Each of the plurality of LC parallel resonant circuits S is set to resonate with respect to a frequency in the frequency band of 2.4 GHz to 2.5 GHz. In addition, the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the prescribed communication frequency. In addition, as Figure 5 As shown, the LC parallel resonant circuit S is configured to form a series circuit and a parallel circuit, and each LC parallel resonant circuit S is formed to be magnetically coupled or electrically coupled to each other, so that the level of the electromagnetic wave is greatly attenuated in the wide band of the 2.4 GHz to 2.5 GHz frequency band. In addition, Figure 6 This is a diagram showing a partial configuration example of a plurality of LC parallel resonant circuits S in the RFID tag 1 according to the first embodiment using an analog equivalent circuit. Figure 7 This is a diagram showing an example of the overall configuration of a plurality of LC parallel resonant circuits in the wireless communication device according to the first embodiment using an equivalent circuit.

[0133] Figure 8 : is a frequency characteristic diagram showing the result of a simulation experiment conducted on the RFID tag 1 according to the first embodiment. Fig. 9 This is a Smith chart in a simulation experiment related to the RFID tag 1 of the first embodiment. Figure 8In the frequency characteristic diagram shown, at the frequency of 0.86 GHz shown by ▽m1, the power feed level is -10.2 dB, and at the frequency of 0.92 GHz shown by ▽m2, the power feed level is -9.1 dB. In addition, at the frequency of 2.4 GHz shown by ▽m3, which is the frequency of the heating electromagnetic wave used in the "microwave oven", the power feed level is -49.6 dB, and at the frequency of 2.5 GHz shown by ▽m4, the power feed level is -49.4 dB, which shows that the power feed level is greatly attenuated. In addition, it can be seen that the bandwidth of the frequency higher than the communication frequency is attenuated, not limited to 2.4 GHz to 2.5 GHz. For example, for frequencies above about 1.2 GHz, the power feed level is attenuated to more than -30 dB.

[0134] In addition, if Fig. 9 As shown in the Smith chart shown in , at the frequency of 0.86 GHz shown in ▽m1 and the frequency of 0.92 GHz shown in ▽m2, the impedance characteristics are in an acceptable state. In addition, regarding the RFID tag 1 of Embodiment 1, at the frequency of 2.4 GHz shown in ▽m3 and the frequency of 2.5 GHz shown in ▽m4, it is in a substantially short-circuited state (in the Smith chart, the mark is located at the 0Ω point at the left end), which is obtained through simulation experiments.

[0135] As described above, it can be seen that in the RFID tag 1 of embodiment 1, the high-frequency signal (wireless signal) having a communication frequency in the UHF band (900MHz band, for example 920MHz) is in a frequency band that can be sent and received, while the heating frequency (2.4GHz~2.5GHz) used by the "microwave oven" as an electromagnetic wave heating device is in a frequency band where the feeding level is greatly attenuated (about -50dB).

[0136] In the RFID tag 1 of the first embodiment, the heating frequency (2.4 GHz to 2.5 GHz) used by the "microwave oven" is greatly attenuated (about -50 dB), but the feeding level is not completely zero. That is, when the RFID tag 1 of the first embodiment is heated by the medium through the "microwave oven" together with the commodity, a very small current flows through the antenna pattern 3 (3a, 3b).

[0137] Fig. 10A and Fig. 10B The flow of current when a signal of a communication frequency (920 MHz) in the UHF band is received in the RFID tag 1 of the first embodiment is obtained through a simulation experiment. Fig. 10A ) and the flow of current when receiving a signal at the heating frequency (2.4GHz) used by a "microwave oven" ( Fig. 10B ). Fig. 10A and Fig. 10BIn FIG. 1 , the magnitude of the current flowing through the antenna pattern 3 (3a, 3b) and the line capacitance pattern 4 (4a, 4b) during reception is represented by color and is represented by a non-color black and white. Fig. 10A and Fig. 10B It is not easy to distinguish, but according to the experimental results of the inventors, it is obvious that the current flowing when receiving the heating frequency (2.4GHz) signal is significantly reduced compared with the current flowing when receiving the communication frequency (920MHz) signal. Fig. 10A and Fig. 10B In, it can be seen that Fig. 10A The color ratio in the antenna pattern 3 (3a, 3b) Fig. 10B The color in the antenna pattern 3 (3a, 3b) is darker, and the current when receiving a signal of the communication frequency (920MHz) is greater than the current when receiving a signal of the heating frequency (2.4GHz).

[0138] Fig.11 : is a diagram showing the direction in which the current tries to flow in the respective patterns (3, 4) when the antenna pattern 3 and the line capacitance pattern 4 (first line capacitance electrode 4a) receive a signal having a heating frequency (2.4 GHz). Fig.11 In FIG. 1 , the solid arrow P indicates the direction of the current flowing through the antenna pattern 3 when a signal of the heating frequency (2.4 GHz) is received. In addition, the dotted arrow Q indicates the direction of the current flowing in the "band stop filter" when the current indicated by the solid arrow P flows through the antenna pattern 3. The "band stop filter" is a plurality of LC parallel resonant circuits S formed by the antenna pattern 3 and the line capacitance pattern 4.

[0139] like Fig.11As shown in the figure, when the RFID tag 1 is heated by the medium and receives a signal of the heating frequency (2.4 GHz) so that the current indicated by the solid arrow P flows through the antenna pattern 3, in each of the LC parallel resonant circuits S, the current indicated by the dashed arrow Q tries to flow through the antenna pattern 3. That is, in each LC parallel resonant circuit S, a current (the dashed arrow Q) in the direction opposite to the direction P (the solid arrow) of the current flowing through the antenna pattern 3 tries to flow. As a result, the currents that try to flow in the antenna pattern 3 and the LC parallel resonant circuit S become mutually offset, thereby suppressing the following phenomenon: the antenna pattern 3 receives power from the electromagnetic wave heating device and a large current flows, thereby suppressing the antenna pattern 3 from heating to a high temperature. In addition, in the structure of the RFID tag 1, even if the antenna pattern 3 is locally heated and the antenna pattern 3 is locally sublimated so that a part of the antenna pattern 3 is disconnected, since the LC parallel resonant circuit S is formed in the entire antenna pattern, even if the antenna pattern 3 separated by the disconnection receives power from the electromagnetic wave heating device, the phenomenon of a large current flowing through the antenna pattern 3 due to the electromagnetic wave heating device can be suppressed. That is, in the structure of the RFID tag 1, Fig.11 The relationship between the LC parallel resonant circuit S shown and the antenna pattern 3 is established, so the phenomenon that a large current flows through the antenna pattern 3 due to the electromagnetic wave heating device is suppressed until the antenna pattern 3 is finally disconnected (divided) into an antenna pattern piece that is too short to receive the power of the electromagnetic wave heating device. As a result, even if the RFID tag 1 of embodiment 1 receives a signal of the heating frequency (2.4 GHz), the current flowing through the antenna pattern 3 is greatly attenuated (for example, about -50 dB). In addition, in the loop circuit of the LC parallel resonant circuit S having the inter-line capacitance electrode 4a arranged at the folded portion of the antenna pattern 3, a current that does not cancel the current flowing through the antenna pattern 3 flows through the inter-line capacitance electrode 4a. A magnetic field is generated by this current, so a part of the power fed to the LC parallel resonant circuit S is lost as magnetic field energy. As a result, in the RFID tag 1 of embodiment 1, a circuit structure is formed that can greatly attenuate the bandwidth of the heating frequency (2.4 GHz) by using a "band rejection filter" as a plurality of LC parallel resonant circuits S. Furthermore, the RFID tag 1 of the first embodiment has a circuit configuration capable of significantly attenuating the bandwidth (2.4 GHz to 2.5 GHz) of the heating frequency used in a “microwave oven” as an electromagnetic wave heating device.

[0140] Fig. 12A and Fig. 12B This is a diagram showing the gain of the RFID tag 1 according to the first embodiment in all directions. Fig. 12A and Fig. 12B The X direction in FIG. 1 represents the long side direction of the RFIC package 2 in the RFID tag 1. Fig. 12A and Fig. 12B As shown, the gain of the RFID tag 1 in the Y and Z directions becomes higher, and has wide directivity in the Y and Z directions. In addition, in the RFIC package 2, only the gain in its long side direction (X direction) is slightly lower than in other directions, but it has wide directivity as a whole.

[0141] In addition, in the RFID tag 1 of the first embodiment, all of the LC parallel resonant circuits S of the plurality of LC parallel resonant circuits S formed by the antenna pattern 3 and the line capacitance pattern 4 are set to resonate with respect to the frequency of the frequency band (2.4 GHz to 2.5 GHz) used by the electromagnetic wave heating device, but in the present invention, it is not necessary to make all of the LC parallel resonant circuits S resonate at the frequency used by the electromagnetic wave heating device. It is sufficient as long as the structure can significantly attenuate the current flowing through the antenna pattern 3 when the RFID tag 1 is heated by the medium through the electromagnetic wave heating device.

[0142] As described above, the RFID tag 1 of the first embodiment is a wireless communication device for transmitting and receiving a high-frequency signal having a predetermined communication frequency, and includes: an antenna pattern 3 having an inductance component; an RFIC chip 9 electrically connected to the antenna pattern 3; and an inter-line capacitance pattern 4 as a capacitive coupling portion, which capacitively couples specific opposing regions 3aa of the antenna pattern 3 facing each other at multiple locations of the antenna pattern 3 to form an LC parallel resonant circuit. With such a simple structure, even if the RFID tag 1 is irradiated with an electromagnetic wave having a frequency higher than the communication frequency, the LC parallel resonant circuit S functions as a band-stop filter, and thus the irradiated electromagnetic wave having a frequency higher than the communication frequency can be significantly attenuated.

[0143] The RFID tag 1 as a wireless communication device of Embodiment 1 is provided with a "band rejection filter" composed of a plurality of LC parallel resonant circuits S, which are composed of an antenna pattern 3 as a metal film body provided on both sides of a dielectric and a line capacitance pattern 4 as a capacitive coupling portion. Therefore, the RFID tag 1 of Embodiment 1 is a structure capable of significantly attenuating the frequency of the frequency band (2.4 GHz to 2.5 GHz) used by the electromagnetic wave heating device.

[0144] Furthermore, the resonant frequency of the RFID tag 1 is adjusted to the communication frequency of the UHF band by forming the inter-line capacitance pattern 4 on the antenna pattern 3. The resonant frequency of the antenna pattern 3 without the inter-line capacitance pattern 4 is higher than the communication frequency, for example, about 1.1 GHz.

[0145] In addition, when the RFID tag 1 of embodiment 1 is heated by the medium through the electromagnetic wave heating device, the current flows through the loop circuit which is the minimum path formed by the antenna pattern 3 and the line capacitance pattern 4, so the loop circuit becomes a small magnetic field antenna at the frequency of the electromagnetic wave heating device, and becomes a structure that is not easy to receive the electric field energy radiated by the electromagnetic wave heating device. As a result, in a single loop circuit, the following structure is formed: it is not easy to ignite due to the electromagnetic wave heating device, and the received electric field energy (electricity) can be lost as magnetic field energy. As a result, in the RFID tag 1 of embodiment 1, a structure is formed that can greatly attenuate the feeding level when the medium is heated. Although the feeding level is greatly attenuated, the antenna pattern 3 is gradually heated by the small current flowing through the antenna pattern 3, and by making the line width of the antenna pattern 3 about 100μm to 300μm, the antenna pattern 3 can be easily disconnected by the deformation of the antenna substrate 5. As a result, the antenna substrate 5 is deformed due to the heating of the antenna pattern 3, so that the antenna pattern 3 is broken. Therefore, the antenna pattern 3 will gradually break until the antenna pattern 3 no longer receives electromagnetic waves heated by the medium. Therefore, even if the RFID tag is heated by the medium, the entire tag will not burn.

[0146] In addition, the RFID tag 1 of embodiment 1 is configured as follows: the antenna pattern 3 and the line-to-line capacitance pattern 4 are configured as curved surfaces having a shape capable of suppressing the concentration of the electric field, and the wide-shaped first line-to-line capacitance electrode 4a at least capacitively couples the adjacent folded portions of the first antenna element 3a and the second antenna element 3b. Therefore, the RFID tag 1 of embodiment 1 is configured as follows: when the RFID tag 1 is heated by the medium through the electromagnetic wave heating device, the concentration of the electric field at the folded portions of the first antenna element 3a and the second antenna element 3b is suppressed.

[0147] Since it is constructed as described above, even when the commodity with the RFID tag 1 of embodiment 1 is subjected to dielectric heating in an electromagnetic wave heating device (microwave oven), the occurrence of discharge in the RFID tag 1 is greatly suppressed, thereby preventing the risk of fire in the commodity.

[0148] Implementation Method 2

[0149] Next, an RFID tag 21 as a wireless communication device according to Embodiment 2 of the present invention will be described. The RFID tag 21 according to Embodiment 2 will be described with a focus on the differences from the RFID tag 1 according to Embodiment 1. In the description of Embodiment 2, elements having the same structure, function, and function as those in Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are sometimes omitted to avoid duplication.

[0150] The RFID tag 21 of the second embodiment is different from the RFID tag 1 of the first embodiment in the structure of the antenna pattern 23 , and the other structures are substantially the same as those of the RFID tag 1 of the first embodiment. Fig.13 It is a plan view showing the structure of the RFID tag 21 according to Embodiment 2. The RFID tag 21 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the UHF band, and is configured to be capable of wireless communication in a wide band.

[0151] The RFID tag 21 of the second embodiment is different from the RFID tag 1 of the first embodiment in that the cross-sectional shape (cross-sectional shape obtained by cutting in a direction perpendicular to the extending direction) of a specific area in the linear antenna pattern 23 is formed small. The RFIC package 2 and the antenna substrate 5 of the second embodiment are substantially the same as the RFIC package and the antenna substrate of the RFID tag 1 of the first embodiment.

[0152] As described in the aforementioned embodiment 1, the following structure is used: when the RFID tag 21 is heated by the medium in a "microwave oven" as an electromagnetic wave heating device, the RFID tag 21 greatly attenuates the feeding level of the heating frequency (2.4 GHz to 2.5 GHz) used by the "microwave oven" (about -50 dB). In this way, in the RFID tag 21, the feeding level of the heating frequency (2.4 GHz to 2.5 GHz) is greatly attenuated (about -50 dB), but since the feeding level is not zero, a very small current flows in the antenna pattern 23. As a result, the antenna pattern 23 generates heat due to its own resistance. In particular, when the RFID tag as a wireless communication device is heated by the medium through the "microwave oven" for a long time (several minutes), the antenna pattern itself becomes high temperature, and there is no complete concern that the antenna substrate, etc., will catch fire.

[0153] In the second embodiment, the following structure is adopted: when the RFID tag 21 as a wireless communication device is heated by a medium in a "microwave oven" for a long time (several minutes), a specific portion of the antenna pattern 23 is sublimated and cut off. In the RFID tag 21 of the second embodiment, the cross-sectional area of ​​a specific portion (disconnection forming portion C) in the linear antenna pattern 23 is formed to be small. That is, the cross-sectional area of ​​the cross-section of the disconnection forming portion C in the antenna pattern 23, which is cut in a direction orthogonal to the extension direction of the specific portion in the antenna pattern 23, is formed to be smaller than the cross-sectional area of ​​other portions. As a structure of the disconnection forming portion C with a small cross-sectional area, it can be formed by making the line of the antenna pattern 23 thin (narrow) or thin.

[0154] As a specific structure of the disconnection forming portion C, for example, the following structure is used: the wiring width of a specific portion in the antenna pattern 23 is locally thinned compared to other portions, for example, locally thinned from 100μm to about 50μm; or, the thickness is thinned from 9μm to 6μm. In this way, a portion that is easy to disconnect when the antenna substrate 5 is deformed is formed. As a disconnection forming portion C in the antenna pattern 23 in which the cross-sectional area is formed smaller than other portions, it is preferably a portion between the line capacitance patterns that serve as the capacitance coupling portion in the LC parallel resonant circuit S that constitutes a "band-stop filter". Each of the multiple LC parallel resonant circuits S is set to resonate with a frequency in the frequency band of 2.4GHz to 2.5GHz, and the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the specified communication frequency, and is less than 1 / 4 wavelength (λ / 4) of the frequency band of the heating electromagnetic wave (2.4GHz to 2.5GHz). Fig.13 2 shows an example in which the disconnection forming portion C is formed on the line between the inter-line capacitance patterns 4 constituting the LC parallel resonant circuit S of the antenna pattern 3 .

[0155] Therefore, when the RFID tag 21 is heated by the "microwave oven" medium for a long time and the disconnection forming part C of the antenna pattern 23 is sublimated and cut off, the line length of each part of the antenna pattern 23 after the disconnection becomes less than 1 / 4 wavelength (λ / 4) of the frequency band of the heating electromagnetic wave (2.4GHz~2.5GHz), so it is not easy to receive electromagnetic waves under the heating electromagnetic wave (2.4GHz~2.5GHz), thereby preventing the temperature in the LC parallel resonant circuit S from further rising due to the frequency (2.4GHz~2.5GHz) of the heating electromagnetic wave used by the "microwave oven".

[0156] Furthermore, in the RFID tag 21 of the second embodiment, as the antenna substrate 5 provided between the antenna pattern 23 and the inter-line capacitance pattern 24, a heat-resistant label seal, such as a polyester resin, a polyimide resin, or the like, having a heat-resistant temperature of 200°C or higher and a durability of 5 minutes or more is used, so that even when the temperature of the antenna pattern 23 rises and the antenna substrate 5 is heated, the dielectric capacitance between the antenna pattern 23 and the inter-line capacitance pattern 24 can be reliably ensured. In addition, a film body formed of a heat-resistant material may be interposed between the antenna substrate 5 and the antenna pattern 23 and / or between the antenna substrate 5 and the inter-line capacitance pattern 24 to further improve the heat resistance.

[0157] In the RFID tag 21 of embodiment 2 constructed as described above, even when the product with the RFID tag 21 is heated by a medium in an electromagnetic wave heating device (microwave oven), the risk of fire in the RFID tag 21 can be prevented. The RFID tag 21 is a wireless communication device with high safety and reliability.

[0158] Implementation Method 3

[0159] Next, an RFID tag 31 as a wireless communication device according to Embodiment 3 of the present invention will be described. The RFID tag 31 according to Embodiment 3 will be described with a focus on the differences from the RFID tag 1 according to Embodiment 1. In the description of Embodiment 3, elements having the same structure, function, and function as those in Embodiment 1 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0160] The RFID tag 31 of the third embodiment is greatly different from the RFID tag 1 of the first embodiment in the shape of the meander-shaped antenna pattern 33 . Fig.14 It is a plan view showing the structure of the RFID tag 31 according to Embodiment 3. The RFID tag 31 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the UHF band, and is configured to be capable of wireless communication in a wide band.

[0161] In the RFID tag 31 of the third embodiment, the top view shape of the RFID tag 31 is formed to be more slender than the RFID tag 1 of the first embodiment, and the RFIC package 2 is installed in the center. That is, the antenna substrate 35 of the RFID tag 31 has a slender shape, and the antenna pattern 33 (the first antenna element 33a and the second antenna element 33b) is provided on both sides of the RFIC package 2 installed in the center of the antenna substrate 35. The first antenna element 33a is formed in a region on one side in the long side direction of the antenna substrate 35 (at Fig.14 On the other hand, the second antenna element 33b is formed in the region on the other side in the long side direction of the antenna substrate 35 (in the region on the right side). Fig.14 The left side area is shown in the middle), and it extends in a winding manner toward the other end in the long side direction.

[0162] In the RFID tag 31 of the third embodiment, the line capacitance pattern 34 as the capacitive coupling portion is arranged to capacitively couple the adjacent folded portions of the meandering first antenna element 33a and the second antenna element 33b. In this way, in the RFID tag 31 of the third embodiment, a plurality of LC parallel resonant circuits S are formed along the respective paths of the first antenna element 33a and the second antenna element 33b having an inductance component, and these LC parallel resonant circuits S constitute a "band stop filter". In each of the plurality of LC parallel resonant circuits S of the third embodiment, it is also arranged to resonate with respect to the frequency of the frequency band of 2.4 GHz to 2.5 GHz used by the "microwave oven". In addition, the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the prescribed communication frequency.

[0163] The RFID tag 31 of the third embodiment is formed such that, in a loop circuit as a minimum path formed by the antenna pattern 33 and the line capacitance pattern 34, the line length between the line capacitance patterns 34 provided in the opposite folded portions is shorter than 1 / 2 wavelength of the frequency used as the prescribed communication frequency, and is less than 1 / 4 wavelength of the wavelength (λ) of the frequency band (2.4 GHz to 2.5 GHz) used by the "microwave oven". That is, the line length between the folded portions in the path of the first antenna element 33a and the second antenna element 33b is set to be shorter than 1 / 4 wavelength (λ / 4: about 30 mm to 34 mm) of the wavelength (λ) of the frequency band (2.4 GHz to 2.5 GHz). Therefore, the RFID tag 31 of the third embodiment has a simple structure of a small band with a narrow width, so that a wireless communication device that is easy to use and inexpensive can be constructed.

[0164] Fig.15 The modified example of the third embodiment is a top view showing the structure of an RFID tag 41 in which an RFIC chip 9 is mounted on an antenna pattern 43. The RFID tag 41 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the UHF band, and is configured to be capable of wireless communication in a wide frequency band. Fig.15 In the RFID tag 41 shown, the RFIC chip 9 is mounted on the antenna pattern 43 formed on the loop portion 40, and other than this structure, it has the same Fig.14The RFID tag 41 has the same structure as the RFID tag 31 shown in the figure. That is, the antenna substrate 45 of the RFID tag 41 has an elongated shape, and the antenna pattern 43 (the first antenna element 43a and the second antenna element 43b) is provided on both sides of the loop portion 40 formed in the center of the antenna substrate 45. In the RFID tag 41, multiple (plural) LC parallel resonant circuits S are formed along the respective paths of the first antenna element 43a and the second antenna element 43b having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter".

[0165] exist Fig.15 Each of the multiple LC parallel resonant circuits S of the RFID tag 41 shown is also set to resonate with a frequency in the frequency band of 2.4 GHz to 2.5 GHz used by the "microwave oven", and the line length in each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the specified communication frequency.

[0166] In addition, Fig.15 In the RFID tag 41 shown, in the path of the winding first antenna element 43a and the second antenna element 43b, the line length between the line-to-line capacitance pattern 44 arranged in the return portion is set to be less than 1 / 4 wavelength (λ / 4: approximately 30mm to 34mm), and the RFID tag 41 has a narrow strip shape, becoming a wireless communication device that is easy to use and does not obstruct the purchaser in the product display.

[0167] As described above, in the RFID tags 31 and 41 of embodiment 3, even when the goods carrying the RFID tags 31 and 41 are heated by the medium in the electromagnetic wave heating device (microwave oven), the risk of fire in the RFID tag 21 can be prevented. The RFID tags 31 and 41 are easy-to-use wireless communication devices that are highly safe and reliable and do not interfere with the display of goods.

[0168] In addition, in the RFID tags 31 and 41 described in the third embodiment, the following structure may be adopted: the disconnection forming portion C described in the aforementioned second embodiment is formed in the antenna patterns 33 and 43. In addition, in the RFID tags 31 and 41 of the third embodiment, the corner portions in the antenna pattern 3 and the line capacitance pattern 4 are configured as curved surfaces in order to suppress the concentration of the electric field.

[0169] Implementation Method 4

[0170] Next, an RFID tag 51 as a wireless communication device according to Embodiment 4 of the present invention will be described. The RFID tag 51 according to Embodiment 4 will be described with a focus on the differences from the RFID tag 1 according to Embodiment 1. In the description of Embodiment 4, elements having the same structure, function, and function as those in Embodiment 1 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0171] Fig.16A It is a plan view showing the structure of an RFID tag 51 according to Embodiment 4. The RFID tag 51 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and is configured to be capable of wireless communication in a wide band. Fig. 16B This is a diagram showing the structure of an antenna pattern (coil pattern) 53 in an RFID tag 51 according to the fourth embodiment using an equivalent circuit.

[0172] like Fig.16A As shown, the RFID tag 51 has an antenna pattern 53, and the antenna pattern 53 has a matching circuit of a loop portion 50 provided with an RFIC chip 9 and a capacitor element 52. In addition, in the matching circuit of the loop portion 50, the capacitor element 52 is connected at a position facing the RFIC chip 9. The antenna element 53a of the antenna pattern 53 in the RFID tag 51 extends from the loop portion 50 and is formed in a spiral shape. Fig.16A In the antenna element 53a shown, the antenna element 53a is led out from the loop portion 50 in a manner of winding inward in the clockwise direction. The terminal portion of the antenna element 53a, which is the lead-out end portion, is directly connected to the matching circuit of the loop portion 50 via the bridge pattern 56. In addition, an insulating pattern 57 formed of a heat-resistant electrical insulating material is provided between the bridge pattern 56 and the antenna pattern 53, thereby ensuring the insulation state between the bridge pattern 56 and the antenna pattern 53.

[0173] In addition, in the spiral antenna element 53a led out from the matching circuit of the loop portion 50, a plurality of inter-line capacitance patterns 54 as capacitance coupling portions for capacitance coupling between adjacent paths are provided at predetermined intervals along the path of the antenna element 53a. An insulation pattern 57 formed of a heat-resistant electrical insulation material is provided between the inter-line capacitance pattern 54 and the antenna element 53a, thereby ensuring the insulation state between the inter-line capacitance pattern 54 and the antenna element 53a.

[0174] As described above, in the RFID tag 51 of the fourth embodiment, a plurality of LC parallel resonant circuits S are formed along the path of the antenna element 53a having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter". In each of the plurality of LC parallel resonant circuits S of the RFID tag 51, it is also set to resonate with a frequency in the frequency band of 2.4 GHz to 2.5 GHz used by the "microwave oven", and the line length in each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the predetermined communication frequency.

[0175] In the RFID tag 51 of the fourth embodiment, the antenna pattern 53 and the line capacitance pattern 54 as the capacitance coupling part are stacked on the surface (first main surface) of the antenna substrate 55, and the insulating pattern 57 as a dielectric is sandwiched between the antenna pattern 53 and the line capacitance pattern 54 as the capacitance coupling part. In addition, on the surface (first main surface) of the antenna substrate 55, a bridge pattern 56 is formed on the antenna pattern 53 via the insulating pattern 57, thereby constituting the antenna in the RFID tag 51. Therefore, it is a structure in which a plurality of patterns (53, 57, 56 and 54) are formed on the same surface of the antenna substrate 55, and thus it becomes a structure that is easy to manufacture the RFID tag 51. In addition, in the RFID tag 51 of the fourth embodiment, the antenna substrate 55 does not need to be composed of a dielectric, and can be composed of, for example, a paper material.

[0176] As in the above-mentioned embodiment 1, Fig.11 As described above, in the RFID tag 51 of the fourth embodiment, a circuit structure is also formed that can significantly attenuate the frequency of the bandwidth of the heating frequency (2.4 GHz to 2.5 GHz) by using a "band rejection filter" composed of a plurality of LC parallel resonant circuits S. Therefore, in the RFID tag 51 as a wireless communication device of the fourth embodiment, a structure is formed that can perform wireless communication by using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and the following structure is formed: even when the dielectric of the commodity with the RFID tag 51 is heated in an electromagnetic wave heating device (microwave oven), the occurrence of discharge in the RFID tag 51 is significantly suppressed, thereby reliably preventing the danger of fire in the commodity.

[0177] Implementation Method 5

[0178] Next, an RFID tag 61 as a wireless communication device according to Embodiment 5 of the present invention will be described. The RFID tag 61 according to Embodiment 5 will be described with a focus on the differences from the RFID tag 1 according to Embodiment 1. In the description of Embodiment 5, elements having the same structure, function, and function as those in Embodiment 1 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0179] Fig.17A It is a plan view showing the structure of an RFID tag 61 according to Embodiment 5. The RFID tag 61 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and is configured to be capable of wireless communication in a wide band. Fig. 17B This is a diagram showing the structure of two coil patterns (63, 73) including an antenna pattern in an RFID tag 61 according to the fifth embodiment using an equivalent circuit.

[0180] like Fig.17A As shown, in the RFID tag 61 of the fifth embodiment, a resonant booster circuit having two coil patterns (63, 73) is configured. One of the coil patterns (primary side coil pattern) 73 in the RFID tag 61 has a matching circuit of a loop portion 70 provided with an RFIC chip 9 and a capacitor element 72. In the matching circuit of the loop portion 70, the RFIC chip 9 is connected to a position facing the capacitor element 72. The coil pattern (primary side coil pattern) 73 is led out from the loop portion 70 in a spiral shape, and the terminal portion of the coil pattern 73 as the lead-out end portion is directly connected to the matching circuit of the loop portion 70 via a bridge pattern 74. The coil pattern (primary side coil pattern) 73 is led out from the loop portion 70 in a clockwise direction in an inwardly wound manner.

[0181] Furthermore, a bridge pattern 74 may be formed on the back side (second main surface) of the antenna substrate 65, and the terminal portion of the coil pattern (primary side coil pattern) 73 as the lead end portion may be connected to the loop portion 70 via an interlayer connection conductor that penetrates the antenna substrate 65. Alternatively, in the case where the bridge pattern 74 is formed on the front side (first main surface) of the antenna substrate 65, the following structure may be used: an insulating pattern formed of a heat-resistant electrical insulating material is provided between the bridge pattern 74 and the primary side coil pattern 73, thereby ensuring the insulation state between the bridge pattern 74 and the primary side coil pattern 73.

[0182] In addition, another coil pattern (secondary coil pattern) 63 in the RFID tag 61 of Embodiment 5 is formed to surround the coil pattern (primary coil pattern) 73, and is formed to have an antenna element 63a formed in a manner of winding inward in the clockwise direction. In the spiral antenna element 63a of the antenna pattern 63, a plurality of line-to-line capacitance patterns 64 as capacitance coupling portions for capacitance coupling between adjacent paths are arranged at predetermined intervals along the path of the antenna element 63a.

[0183] The antenna pattern 63 in the RFID tag 61 of the fifth embodiment is formed on the surface (first main surface) of the antenna substrate 65. On the other hand, the line capacitance pattern 64 as a capacitive coupling portion is formed on the back side (second main surface) of the antenna substrate 65 composed of a dielectric, and capacitive coupling is performed on a specific area in the antenna element 63a of the antenna pattern 63. In addition, a capacitor element 62 is provided on the antenna element 63a of the antenna pattern 63. The outer end and the inner end of the spiral antenna element 63a are directly electrically connected via the interlayer connection conductor 66 that penetrates the antenna substrate 65 and through the conductive path pattern 67 formed on the back side (second main surface) of the antenna substrate 65. In addition, the line capacitance pattern 64 and the conductive path pattern 67 formed on the back side (second main surface) of the antenna substrate 65 can be formed at the same time.

[0184] As described above, in the RFID tag 61 of the fifth embodiment, a plurality of LC parallel resonant circuits S are formed along the path of the antenna element 63a of the antenna pattern 63 having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter". In each of the plurality of LC parallel resonant circuits S of the RFID tag 61, it is also set to resonate with a frequency in the frequency band of 2.4 GHz to 2.5 GHz used by the "microwave oven". In addition, the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the predetermined communication frequency.

[0185] The RFID tag 61 of the fifth embodiment constructed as described above is a circuit structure capable of significantly attenuating the frequency of the bandwidth of the heating frequency (2.4 GHz to 2.5 GHz) by using a "band rejection filter" composed of a plurality of LC parallel resonant circuits S. Therefore, in the RFID tag 61 as a wireless communication device of the fifth embodiment, it is a structure capable of wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and has the following structure: even when the dielectric of the commodity with the RFID tag 61 is heated in an electromagnetic wave heating device (microwave oven), the occurrence of discharge in the RFID tag 61 is significantly suppressed, thereby reliably preventing the danger of fire in the commodity.

[0186] As described above, as described using specific structures in each embodiment, according to these embodiments, it is possible to provide a wireless communication device with high safety and reliability as follows: even if a commodity with a wireless communication device is mistakenly heated by an electromagnetic wave heating device while the commodity is equipped with the wireless communication device, the occurrence of discharge in the wireless communication device is suppressed, thereby preventing the wireless communication device from catching fire, and further preventing the danger of catching fire in the commodity equipped with the wireless communication device. Therefore, the present invention provides a wireless communication device as follows: in a sales store such as a convenience store that trades a variety of commodities such as food and daily groceries, the wireless communication device enables the construction of a system that automates the settlement and bagging of purchased commodities, thereby greatly promoting the practical application of "unmanned convenience stores".

[0187] Implementation Method 6

[0188] Below, refer to Fig.18 An RFID tag as a wireless communication device according to a sixth embodiment of the present invention will be described. Fig.18 It is a top view showing the structure of the RFID tag 81 according to the sixth embodiment.

[0189] The RFID tag 81 of Embodiment 6 is described with a focus on the differences from the RFID tag 1 of Embodiment 1. In addition, in the description of Embodiment 6, elements having the same structure, action, and function as those of the aforementioned Embodiment 1 are marked with the same reference marks, and the description is sometimes omitted to avoid repeated description. In addition, the structure of the RFID tag 81 of Embodiment 6 is substantially the same as the structure of the RFID tag 1 of Embodiment 1 except for the structure described below.

[0190] The RFID tag 1 of the first embodiment has an antenna pattern 3 formed on the surface of the antenna substrate 5, and an inter-line capacitance pattern 4 as a capacitive coupling portion formed on the back surface of the antenna substrate 5. In contrast, the RFID tag 81 of the sixth embodiment has both an antenna pattern 83 and an inter-line capacitance pattern 85 formed on the surface of the antenna substrate 5.

[0191] An antenna pattern 83 as an electric field radiation type antenna pattern is formed on the surface of the antenna substrate 5. The antenna pattern 83 includes: a first antenna element 83a having a meandering antenna pattern that is bent in a manner having a plurality of folded portions 83ac; and a second antenna element 83b connected to the wide portion 7. The folded portion 83ac of the antenna pattern 83 refers to a portion where the direction in which the antenna pattern 83 extends is reversed. The antenna element 83a has a plurality of folded portions 83ac. The first antenna element 83a has a straight portion 83aa parallel to the width direction (Y direction) of the antenna substrate 5. An inter-wire capacitance pattern 85 is formed between adjacent straight portions 83aa and adjacent folded portions 83ac of the first antenna element 83a. The interval between the antenna element 83a and the inter-wire capacitance pattern 85 is, for example, 150 μm.

[0192] The inter-line capacitance pattern 85 is formed of a conductive material such as aluminum foil or copper foil, similarly to the antenna pattern 83. When formed of aluminum foil, the thickness of the inter-line capacitance pattern 85 is, for example, 6 μm. The inter-line capacitance pattern 85 is formed in a ring shape.

[0193] The inter-wire capacitance pattern 85 includes inter-wire capacitance patterns 85a and 85b of different lengths in the width direction (Y direction) of the antenna substrate 5. The inter-wire capacitance patterns 85a and 85b have a long side direction and a short side direction, and the length of the inter-wire capacitance patterns 85a and 85b in the long side direction is formed to be short, for example, to less than 1 / 4 wavelength of the frequency used in electromagnetic wave heating. In the amplitude direction (Y direction) of the meandering of the antenna pattern 83, the length Wa of the first antenna element 83a is longer than the length Wc1 of the inter-wire capacitance pattern 85a and the length Wc2 of the inter-wire capacitance pattern 85b. The inter-wire capacitance pattern 85 is composed of an elongated closed loop pattern. Therefore, it has the following effect: when operating as a magnetic field antenna, the Q characteristic of the antenna coil deteriorates, and the magnetic field energy is converted into heat due to magnetic loss. Due to the heat, the antenna substrate 5 is deformed by melting or carbonization, the inter-wire capacitance pattern 85 is disconnected, and a part of the antenna pattern 83 is disconnected.

[0194] In the antenna pattern 83 of the sixth embodiment, two pad patterns 6 (6a, 6b) are provided for contacting the RFIC package 2 to be electrically connected to the RFIC package 2. Thus, the RFIC chip 9 of the RFIC package 2 is electrically connected to the antenna pattern 83. In addition, the antenna pattern 83 has a first antenna element 83a and a second antenna element 83b, forming a dipole-type electric field antenna.

[0195] The first antenna element 83a has a substantially linear shape pattern, and is extended in a meandering manner after being drawn out from the first land pattern 6a. The extending direction of the first antenna element 83a is toward one end in the long-side direction of the antenna substrate 5. The terminal end portion of the first antenna element 83a in the extending direction is disposed at the end portion of the antenna substrate 5 in the long-side direction.

[0196] The second antenna element 83b of the antenna pattern 83 is extended linearly toward the other end in the long side direction of the antenna substrate 5 after being led out from the second land pattern 6b, and a wide portion 7 is formed at the terminal portion in the extending direction of the second antenna element 83b. The wide portion 7 is a portion to be attached to a product, and when attached to a product with metal material exposed on the outer surface of the product, such as a canned product, the wide portion 7 enables the outer surface of the product to function as a part of the antenna.

[0197] The first antenna element 83a includes, for example, a straight line portion 83aa extending in the amplitude direction of the meander and parallel to the width direction (Y direction) of the antenna substrate 5. The straight line portion 83aa includes a facing portion 83c, which is located between the line capacitance patterns 85a and 85b in the width direction (Y direction) of the antenna substrate 5 and is a portion facing each other without the line capacitance patterns 85a and 85b between the adjacent straight line portions 83aa in the long side direction (X direction) of the antenna substrate 5. In addition, as the antenna pattern 83 extends in the long side direction of the antenna substrate 5, the line capacitance patterns 85a and the line capacitance patterns 85b are alternately arranged between the straight line portions 83aa, and thus, the positions of the facing portions 83c are shifted in the width direction of the antenna substrate 5.

[0198] An annular shield pattern 87 is formed around the land pattern 6. The shield pattern 87 is formed of a conductive material such as aluminum foil or copper foil, similar to the antenna pattern 3. The shield pattern 87 includes a completely closed annular first shield pattern 87a and a partially interrupted second shield pattern 87b.

[0199] The first shield pattern 87a is a completely closed annular pattern whose long side is shorter than the long side of the line capacitance patterns 85a and 85b. The pattern close to a square is formed by a long side of a degree that will not catch fire even if an electromagnetic wave with a bandwidth of a frequency higher than the communication frequency is received. In the first shield pattern 87a, the current flows in a direction that cancels the magnetic field generated by the current flowing between the first antenna element 83a and the pad patterns 6a and 6b. The first shield pattern 87a is closer to a square than the line capacitance patterns 85a and 85b, so the Q characteristic of the inductance element formed by the pattern is higher than the Q characteristic of the inductance element formed by the line capacitance patterns 85a and 85b, and it is easy to suppress the heat and fire caused by magnetic loss. Therefore, since the first shield pattern 87a is arranged in the central part of the long side direction of the antenna substrate 5, even if it is irradiated with an electromagnetic wave with a bandwidth of a frequency higher than the communication frequency, the heat caused by eddy currents that cause disconnection will not occur.

[0200] In addition, the second shield pattern 87b is partially interrupted. In this pattern, current also flows in a direction that cancels out the magnetic field generated by the current flowing between the first antenna element 83a and the pad patterns 6a and 6b. However, since this pattern is partially interrupted, a discharge occurs at the interrupted portion by irradiating an electromagnetic wave with a bandwidth of a frequency higher than the communication frequency, generating a spark, so that the antenna electrode of the discharge portion of the antenna substrate 5 is partially sublimated. Since there is an antenna pattern near the sublimated position, it has a function of disconnecting the nearby antenna pattern while the substrate is sublimated.

[0201] The extension portion 83ab of the first antenna element 83a extending from the first land pattern 6a and the second antenna element 83b extending from the second land pattern 6b are arranged in mutually intersecting directions, for example, orthogonal directions. This can reduce the potential difference between the extension portion 83ab of the first antenna element and the second antenna element 83b.

[0202] The antenna pattern 83, the line capacitance pattern 85 and the shielding pattern 87 formed on the surface of the antenna substrate 5 as described above have a shape that prevents the concentration of the electric field, and in particular, there are no sharp angles at the edge of the bending portion and the peripheral portion, and all of them are composed of gently curved surfaces.

[0203] In the first embodiment, the RFIC package 2 is mounted on the antenna pattern 83, but the RFIC chip 9 may be directly mounted on the antenna pattern 83. In addition, in this case, the inductor formed as the plurality of inductance elements 10A, 10B, 10C, and 10D in the RFIC package 2 may be formed as a ring-shaped pattern on the antenna substrate 5.

[0204] Fig.19A Yes means Fig.18A top view of a portion of the antenna pattern 83. Fig.19B yes Fig.19A An equivalent circuit diagram of the antenna pattern 83 is shown. Fig.19C It means that when receiving electromagnetic waves with a high frequency bandwidth higher than the communication frequency, Fig.19A An illustration of the current.

[0205] like Fig.19B As shown, the inter-wire capacitance pattern 85 that generates capacitance between specific regions in the first antenna element 83a includes an inter-wire capacitance pattern 85a and an inter-wire capacitance pattern 85b having a shorter perimeter than the inter-wire capacitance pattern 85a. The inter-wire capacitance patterns 85a and 85b are arranged between the respective opposing regions of the antenna pattern 83 at intervals along the direction in which the antenna pattern 83 extends. The inter-wire capacitance patterns 85a and 85b generate capacitance between specific opposing regions in the first antenna element 83a. Therefore, the inter-wire capacitance pattern 85a arranged between the mutually opposing portions of the first antenna element 83a constitutes an LC parallel resonant circuit S. In other words, the inter-wire capacitance pattern 85 and a part of the antenna pattern 83 including the opposing region sandwiching the inter-wire capacitance pattern 85 constitute the LC parallel resonant circuit S. In addition, a plurality of LC parallel resonant circuits S are formed in series and in parallel with the path of the first antenna element 83a. The plurality of LC parallel resonant circuits S resonate at a frequency in a bandwidth higher than the communication frequency.

[0206] Inductance Lm represents the inductance component distributed in the first antenna element 83a. In addition, inductance Ln represents the inductance component distributed in the inter-line capacitance pattern 85. The inductance Lm of the first antenna element 83a and the inductance Ln of the inter-line capacitance pattern 85 facing each other are magnetically coupled. There is an electrostatic capacitance Cs1 between the first antenna element 83a and the inter-line capacitance pattern 85. Since there is an electrostatic capacitance Cs1 between each straight line portion 83aa of the adjacent first antenna element 83a and the inter-line capacitance pattern 85, the straight line portions 83aa of the adjacent first antenna elements 83a are capacitively coupled through these electrostatic capacitances Cs1. The electrostatic capacitance between the adjacent straight line portions 83aa is set to Cs2. By configuring the inter-line capacitance pattern 85 between the wiring patterns of the first antenna element 83a, the part of the facing portion 83c of the first antenna element 83a where the inter-line capacitance pattern 85 does not exist does not have a part that cancels the eddy current, so the magnetic field between the adjacent straight line portions 83aa is not canceled, and the potential difference caused by the overcurrent becomes the maximum.

[0207] When the antenna pattern 83 is irradiated with electromagnetic waves having a bandwidth higher than the communication frequency, as shown in FIG. Fig.19CAs shown in FIG. 1 , due to the electrostatic capacitance Cs2, currents in opposite directions flow through the first antenna element 83a with the opposing portion 83c as a boundary. Due to this current, the potential difference between the opposing portions 83c increases.

[0208] In addition, through the electromagnetic field coupling between the first antenna element 83a and the line capacitance pattern 85, an eddy current in the opposite direction to the current of the adjacent first antenna element 83a flows in the line capacitance pattern 85. In addition, a magnetic field is generated due to the eddy current. Through the generation of this magnetic field, part of the power fed to the LC parallel resonant circuit becomes magnetic field energy, and heat is generated due to the magnetic loss of the line capacitance pattern 85, and the energy is gradually lost. In this way, the bandwidth of the frequency higher than the communication frequency can be attenuated, so the LC parallel resonant circuit functions as a band-stop filter.

[0209] As commodities using the RFID tag 81 of the sixth embodiment, for example, lunch boxes in convenience stores are targeted, so it is assumed that the RFID tag 81 is heated by a medium such as a so-called "microwave oven" which is an electromagnetic wave heating device for cooking. The frequency of microwaves used as electromagnetic waves in the "microwave oven" is in a frequency bandwidth of 2.4 GHz to 2.5 GHz, which is a frequency bandwidth higher than the communication frequency. Therefore, in the RFID tag 81 of the sixth embodiment, a "band rejection filter" is provided as a circuit for significantly attenuating the level of this frequency band. The "band rejection filter" is a filter circuit that attenuates a frequency bandwidth higher than the communication frequency. In the RFID tag 81 of the sixth embodiment, for example, a frequency band higher than 1.1 GHz is attenuated. In particular, the frequency (2.4 GHz to 2.5 GHz) of the electromagnetic waves for heating used in the "microwave oven" is significantly attenuated. The "band rejection filter" is formed by arranging a ring-shaped conductor pattern between the facing areas of the antenna pattern. In addition, by configuring a closed annular conductor pattern that becomes a magnetic field antenna at the frequency of the heating electromagnetic wave near the electric field radiation type antenna, the antenna radiation efficiency of the electric field radiation antenna at the frequency of the heating electromagnetic wave is greatly attenuated, making it difficult to receive the energy of the heating electromagnetic wave. Here, the circumference of the annular conductor pattern is smaller than 1 / 2 wavelength of the frequency of the UHF band used in communication. Thus, at a frequency higher than the frequency of the UHF band, the annular conductor pattern acts as a magnetic field antenna, and the radiation efficiency in the bandwidth of the frequency higher than the frequency of the UHF band can be attenuated. In addition, it can also be that the difference between the circumference of the annular conductor pattern and 1 / 2 wavelength of the frequency of the UHF band used in communication is small. Thus, compared with the frequency near the UHF band, the radiation efficiency near the frequency of the heating electromagnetic wave can be attenuated.

[0210] The operating principle of the band-stop filter is further described in detail. Fig.18 and Fig.19B As shown, in the RFID tag 81 of the sixth embodiment, the line capacitance pattern 85 as a ring-shaped conductor pattern is arranged between the opposing areas of the antenna pattern 83, thereby forming a plurality of LC parallel resonant circuits S along the path of the first antenna element 83a, and these LC parallel resonant circuits S constitute a "band rejection filter". In addition, each of the plurality of LC parallel resonant circuits S is set to parallel resonate with respect to the frequency of the frequency band of 2.4 GHz to 2.5 GHz, thereby operating as a magnetic field antenna. In addition, the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength (λ / 2) of the frequency (2.4 GHz to 2.5 GHz) of the heating electromagnetic wave used in the "microwave oven". In addition, the LC parallel resonant circuits S are arranged to constitute a series circuit and a parallel circuit, and each LC parallel resonant circuit S is formed to be magnetically coupled or electrically coupled to each other, and operates as a magnetic field antenna in the wide band of the frequency band of 2.4 GHz to 2.5 GHz, thereby constituting a plurality of magnetic field antennas near the first antenna element 83a that operates as an electric field antenna. The magnetic field antenna is coupled to the first antenna element 83a that acts as an electric field antenna through electrostatic capacitance, so each part of the pattern of the first antenna element 83a acts locally as a magnetic field antenna. Therefore, the antenna radiation characteristics of the first antenna element 83a as an electric field antenna pattern deteriorate sharply. In addition, the received energy of the first antenna element 83a as an electric field antenna pattern is consumed as heat by the magnetic field antenna. As a result, the reception level of the electromagnetic wave of the electric field antenna pattern is attenuated, and the heating parts are dispersed. In addition, the circumference of the inter-line capacitance patterns 85a and 85b is set to be shorter than 1 / 2 wavelength (λ / 2) of the frequency (2.4GHz~2.5GHz) of the heating electromagnetic wave.

[0211] Fig.28 It is a frequency characteristic diagram showing the results of a simulation experiment conducted on the RFID tag 81 according to the sixth embodiment. Fig.29 This is a Smith chart in a simulation experiment related to the RFID tag 81 of Embodiment 6. Fig.28In the frequency characteristic diagram of the antenna radiation efficiency shown in , the feeding level is -10dB at the frequency of 0.86GHz shown in ▽m1, and the feeding level is -9.6B at the frequency of 0.92GHz shown in ▽m2. In addition, at the frequency of 2.4GHz shown in ▽m3, which is the frequency of the heating electromagnetic wave used in the "microwave oven", the feeding level is -53dB, and at the frequency of 2.5GHz shown in ▽m4, the feeding level is -54dB, which shows that the feeding level is greatly attenuated. In addition, it can be seen that the bandwidth of the frequency higher than the communication frequency is attenuated, not limited to 2.4GHz to 2.5GHz. For example, for frequencies above about 1.2GHz, the feeding level is attenuated to more than -30dB.

[0212] In addition, if Fig.29 As shown in the Smith chart shown in , at the frequency of 0.86 GHz shown in ▽m1 and the frequency of 0.92 GHz shown in ▽m2, the impedance characteristics are in an acceptable state. In addition, regarding the RFID tag 81 of Embodiment 6, at the frequency of 2.4 GHz shown in ▽m3 and the frequency of 2.5 GHz shown in ▽m4, it is in a substantially short-circuited state (in the Smith chart, the mark is located at the 0Ω point at the left end), which is obtained through simulation experiments.

[0213] As described above, it can be seen that in the RFID tag 81 of the sixth embodiment, the high-frequency signal (wireless signal) having the communication frequency of the UHF band (900MHz band, for example, 920MHz) is in the frequency band that can be sent and received, while the heating frequency (2.4GHz to 2.5GHz) used by the "microwave oven" as an electromagnetic wave heating device is in the frequency band where the feeding level is greatly attenuated (about -50dB). This means that the power of the electromagnetic wave heating device of 1000W is attenuated to less than 0.1W, and it is not easy to overheat suddenly and it is not easy to catch fire.

[0214] Thus, in the RFID tag 81 of Embodiment 6, the heating frequency (2.4 GHz to 2.5 GHz) used by the "microwave oven" is greatly attenuated (about -50 dB), but the feeding level is not completely zero. That is, when the RFID tag 81 of Embodiment 6 is heated by the medium through the "microwave oven" together with the commodity, a small current flows through the antenna pattern 83 (3a, 3b). This small current is transmitted from the antenna pattern 83 to the inter-wire capacitance pattern 85 through capacitive coupling, and heat is generated due to the magnetic loss of the inter-wire capacitance pattern 85 that forms the magnetic field antenna, and energy is gradually lost. As a result, the antenna substrate 5 is deformed due to melting or carbonization, and a part of the inter-wire capacitance pattern 85 and / or the antenna pattern 83 is broken. The broken part of the antenna pattern 83 is broken between the closed loops of the inter-wire capacitance pattern 85, thereby cutting the antenna pattern 83 to an electrical length of less than 1 / 4 wavelength (λ / 4) of the heating frequency (2.4 GHz to 2.5 GHz). Since the pattern is disconnected, the antenna pattern 83 is more difficult to receive the heating frequency (2.4 GHz to 2.5 GHz).

[0215] Fig. 30A This is a diagram showing the flow of current when a signal of a communication frequency (920 MHz) in the UHF band is received in the RFID tag 81 of the sixth embodiment, obtained through a simulation experiment. Fig. 30B This is a diagram of the flow of current when a signal of the heating frequency (2.4 GHz) used by a microwave oven is received through a simulation experiment. Fig. 30A and Fig. 30B In FIG. 1 , the result of expressing the magnitude of the current flowing through the antenna pattern 83 (3a, 3b) and the line capacitance pattern 4 (4a, 4b) during reception in color is shown in black and white achromatic colors. Fig. 30A As shown in FIG. 8 , it can be seen that when an electric field in the UHF band is irradiated, current is concentrated on the antenna element 83a of the antenna pattern 83, and the antenna element 83a functions as an antenna. Fig. 30B As shown, it can be seen that when an electric field of 2.4 GHz is irradiated, energy is dispersed to the antenna element 83 a of the antenna pattern 83 , the line capacitance patterns 85 a and 85 b , and the shield pattern 87 .

[0216] Fig.31A This is a diagram showing the gain for all directions related to the RFID tag 81 of the sixth embodiment. Fig.31A The X direction in FIG. 8 represents the long side direction of the RFIC package 2 in the RFID tag 81. Fig.31A and Fig.31BAs shown, the gain of the RFID tag 81 in the Y and Z directions becomes higher, and has wide directivity in the Y and Z directions. In addition, in the RFIC package 2, only the gain in its long side direction (X direction) is slightly lower than that in other directions, but it has wide directivity as a whole.

[0217] In addition, in the RFID tag 81 of the sixth embodiment, all of the LC parallel resonant circuits S of the plurality of LC parallel resonant circuits S formed by the antenna pattern 83 and the line capacitance pattern 85 are set to resonate with respect to the frequency of the frequency band (2.4 GHz to 2.5 GHz) used by the electromagnetic wave heating device, but in the present invention, it is not necessary to make all of the LC parallel resonant circuits S resonate at the frequency used by the electromagnetic wave heating device. It is sufficient as long as the structure can significantly attenuate the current flowing through the antenna pattern 83 when the RFID tag 81 is heated by the medium through the electromagnetic wave heating device.

[0218] As described above, the RFID tag 81 as a wireless communication device of Embodiment 6 is a wireless communication device for transmitting and receiving a high-frequency signal having a first frequency for communication, for example, in the 900 MHz frequency band. The RFID tag 81 includes: a first antenna element 83a of an antenna pattern 83, which has a straight portion 83aa as a facing area facing each other; and an RFIC chip 9, which is electrically connected to the antenna pattern 83. In addition, the RFID tag 81 includes an inter-wire capacitance pattern 85a, which is a ring-shaped conductor pattern arranged between each facing area of ​​the first antenna element 83a. The circumference of the inter-wire capacitance pattern 85a is smaller than half the wavelength of the electromagnetic wave of the first frequency. The antenna pattern 83 and the inter-wire capacitance pattern 85 constitute a "band rejection filter" of the LC parallel resonant circuit S. Therefore, even if the RFID tag 81 is irradiated with an electromagnetic wave of a second frequency higher than the first frequency, the inter-wire capacitance pattern 85a generates a magnetic field as a magnetic field antenna, so that the energy of the electromagnetic wave of the second frequency can be reduced. If only one inter-line capacitance pattern 85a is arranged in the RFID tag 81, the energy irradiated to the vicinity of the inter-line capacitance pattern 85a can be reduced, thereby preventing the product around the inter-line capacitance pattern 85a from being burned.

[0219] In addition, when the RFID tag 81 of embodiment 6 is heated by the medium through the electromagnetic wave heating device, the induced current flows through the ring-shaped inter-wire capacitance pattern 85. As a result, the inter-wire capacitance pattern 85 becomes a small magnetic field antenna at the frequency of the electromagnetic wave heating device, and becomes a structure that reflects the electric field energy radiated by the electromagnetic wave heating device and is not easy to receive the electric field energy. As a result, in the RFID tag 81, the following structure is formed: it is not easy to catch fire due to the electromagnetic wave heating device, and the received electric field energy (electricity) can be reflected or lost as magnetic field energy. Therefore, in the RFID tag 81 of embodiment 6, it becomes a structure that can greatly attenuate the feeding level when the medium is heated.

[0220] In addition, the RFID tag 81 has a plurality of inter-wire capacitance patterns 85a and 85b as ring-shaped conductor patterns, thereby further reducing the energy irradiated to the surrounding of the antenna pattern 83 in the antenna pattern 83. In addition, the adjacent inter-wire capacitance patterns 85a and 85b have different circumferences, so the frequencies of the magnetic field antennas of the inter-wire capacitance patterns 85a and 85b are different, and as a whole, a broadband magnetic field antenna with a bandwidth of 2.4 GHz to 2.5 GHz or more is formed. The first resonant frequency obtained by the inter-wire capacitance pattern 85a and a part of the antenna pattern 83 including the facing area sandwiching the inter-wire capacitance pattern 85a is different from the second resonant frequency obtained by another inter-wire capacitance pattern 85b arranged next to the inter-wire capacitance pattern 85a and another part of the antenna pattern 83 including the facing area sandwiching the inter-wire capacitance pattern 85b. Thus, even if the resonant frequency is shifted due to the dielectric constant of the commercial product due to the RFID tag being attached to the commercial product, a magnetic field antenna that interferes with the electric field antenna can be formed, thereby reducing the electromagnetic wave energy.

[0221] Furthermore, the inter-wire capacitance pattern 85 is formed on the antenna pattern 83, thereby finely adjusting the resonant frequency of the RFID tag 81. For example, compared with the resonant frequency (880 MHz) of the antenna pattern 83 when the inter-wire capacitance pattern 85 is not formed, the antenna resonant frequency is increased by about several 10 MHz to reach a resonant frequency (about 920 MHz) due to the formation of the inter-wire capacitance pattern 85.

[0222] In addition, the RFID tag 81 of embodiment 6 has the following structure: the antenna pattern 83 and the line-to-line capacitance pattern 85 are configured as a curved surface shape having a shape that can suppress the concentration of the electric field, and the line-to-line capacitance pattern 85a is at least arranged between the adjacent folded portions 83ac in the first antenna element 83a and the second antenna element 83b, so that when the RFID tag 81 is heated by the medium through the electromagnetic wave heating device, the concentration of the electric field at the folded portion 83ac of the first antenna element 83a is particularly suppressed.

[0223] Since it is constructed as described above, even when the commodity with the RFID tag 81 of embodiment 6 is subjected to dielectric heating in an electromagnetic wave heating device (microwave oven), the occurrence of discharge in the RFID tag 81 is greatly suppressed, thereby preventing the risk of fire in the commodity.

[0224] In addition, when the potential difference between the opposing portions 83c exceeds a certain value, discharge occurs between the opposing portions 83c. Therefore, for example, when irradiated with electromagnetic waves with high energy such as a microwave oven, discharge occurs between the opposing portions 83c, and the opposing portions 83c are disconnected due to the heat of the discharge. The first antenna element 83a is designed to have a resistance to the extent that it is disconnected due to discharge. In addition, the antenna substrate 5 has a thickness that can be deformed by the heat of the discharge. The thickness of the antenna substrate 5 is, for example, 38μm. As the antenna substrate 5 deforms, the shape of the antenna pattern 3 on the antenna substrate 5 is also deformed, so that the resonance with the irradiated electromagnetic wave is hindered.

[0225] In addition, when a PET film is used as the antenna substrate 5, the antenna substrate 5 at the facing portion 83c melts due to the energy of the electric field becoming strong between the facing portions 83c. Since the antenna substrate 5 at the facing portion 83c directly below the antenna pattern 3 melts, the antenna pattern is stretched and disconnected. Therefore, the antenna pattern 3 is disconnected at the facing portion 83c before discharge occurs between the facing portions 83c.

[0226] These disconnections occur simultaneously at multiple opposing portions 83c in the initial stage before the entire antenna substrate 5 is heated. Therefore, the first antenna element 83a is disconnected simultaneously at multiple locations, so that current no longer flows through the first antenna element 83a, and ignition due to the temperature rise of the entire antenna substrate 5 can be prevented.

[0227] In addition, the length from the facing portion 83c at one end of the straight portion 83aa of the antenna element 83a between the line capacitance pattern 85a and the line capacitance pattern 85b to the next facing portion 83c at the other end is set to be less than 1 / 4 wavelength (λ / 4) of the frequency band of the heating electromagnetic wave (2.4 GHz to 2.5 GHz). Therefore, when a break occurs at each facing portion 83c, the antenna element 83a that is finely broken is less likely to absorb the radio wave of the frequency of the heating electromagnetic wave, so that discharge can be further prevented from occurring in the antenna pattern 83 after the break.

[0228] In addition, the positions of the facing portions 83c are staggered in the width direction (Y direction) of the antenna substrate 5 according to the positions in the long side direction (X direction) of the antenna substrate 5, so the broken wire portions on the first antenna element 83a are also generated in a staggered manner. As a result, the heat generation sites caused by the broken wires can be dispersed on the antenna substrate 5 to prevent the broken wire portions from connecting together and igniting a fire.

[0229] In addition, the electrostatic capacitance Cs2 is formed only between the linear portions 83aa of the adjacent first antenna elements 83a. That is, the electrostatic capacitance is not formed between the linear portions 83aa of the first antenna elements 83a across more than one linear portion 83aa in the long side direction of the antenna substrate 5. Therefore, it is possible to prevent a current from flowing between the linear portions 83aa across more than one linear portion 83aa when the facing portion 83c is disconnected.

[0230] In addition, since the antenna pattern 83 and the line capacitance pattern 85 are formed on one side of the antenna substrate 5, the etching process for forming the pattern can be performed only on one side in the manufacturing process. In addition, the line capacitance pattern 85 may be formed on the back side of the antenna substrate 5. In addition, two or more line capacitance patterns 85 may be arranged in the opposite directions between the linear portions 83aa of the adjacent first antenna elements 83a.

[0231] Implementation Method 7

[0232] Below, refer to Fig. 20 Next, an RFID tag 91 as a wireless communication device according to a seventh embodiment of the present invention will be described. Fig. 20 It is a top view showing the structure of the RFID tag 91 according to the seventh embodiment.

[0233] The RFID tag 91 of the seventh embodiment will be described with a focus on the differences from the RFID tag 81 of the sixth embodiment. In the description of the seventh embodiment, elements having the same structure, action, and function as those of the aforementioned sixth embodiment are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0234] The RFID tag 81 of Embodiment 6 has two inter-line capacitance patterns 85a and 85b between the straight portion 83aa of the first antenna element 83a along the direction in which the first antenna element 83a extends, but may also have three or more inter-line capacitance patterns. The RFID tag 91 of Embodiment 7 has three inter-line capacitance patterns as an example. The length of the inter-line capacitance patterns 85a and 85b in the long side direction (Y direction) of Embodiment 6 is about half the length of the straight portion 83aa of the antenna pattern 83, while the length of the inter-line capacitance patterns 85c and 85d in the long side direction of Embodiment 7 is shorter. In addition, the RFID tag 81 of Embodiment 6 has a second shielding pattern, while the shielding patterns of the RFID tag 91 of Embodiment 7 are all first shielding patterns 87a. The other structures are substantially the same as those of the RFID tag 1 of Embodiment 1.

[0235] By dividing the inter-line capacitance pattern 85b into inter-line capacitance patterns 85c and 85d shorter than the inter-line capacitance pattern 85b in the longitudinal direction, the number of the facing portion 83c can be increased, and the number of discharge locations can be increased. Thus, the discharge location can be changed according to the type of bandwidth of the frequency higher than the communication frequency.

[0236] Similarly, when a frequency higher than the communication frequency is received, eddy currents are generated in the inter-line capacitance patterns 85a, 85c, and 85d to generate a magnetic field, so a portion of the fed power is lost as magnetic field energy. In addition, the potential difference between the opposing portions 83c can be increased and then discharged to disconnect the first antenna element 83a, thereby preventing the entire RFID tag 1 from catching fire.

[0237] Implementation Method 8

[0238] Below, refer to Fig.21 Next, an RFID tag 101 as a wireless communication device according to an eighth embodiment of the present invention will be described. Fig.21 It is a top view showing the structure of the RFID tag 101 according to the eighth embodiment.

[0239] The RFID tag 101 of embodiment 8 is described mainly with respect to the differences from the RFID tag 91 of embodiment 7. In the description of embodiment 8, elements having the same structure, action, and function as those of the aforementioned embodiment 7 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0240] In the RFID tag 91 of the seventh embodiment, the first pad pattern 6a and the second pad pattern 6b are arranged in the width direction of the antenna substrate 5, and in the RFID tag 101 of the eighth embodiment, the first pad pattern 6a and the second pad pattern 6b are arranged in the long side direction of the antenna substrate 5. The other structures are substantially the same as those of the RFID tag 91 of the seventh embodiment.

[0241] Similarly, when a frequency higher than the communication frequency is received, eddy currents are generated in the inter-line capacitance patterns 85a, 85c, and 85d to generate a magnetic field, so a portion of the fed power is lost as magnetic field energy. In addition, the potential difference between the opposing portions 83c can be increased and then discharged to disconnect the first antenna element 83a, thereby preventing the entire RFID tag 1 from catching fire.

[0242] Implementation Method 9

[0243] Below, refer to Fig. 22 The RFID tag 111 as a wireless communication device according to the ninth embodiment of the present invention will be described. Fig. 22 It is a top view showing the structure of the RFID tag 111 according to the ninth embodiment.

[0244] The RFID tag 111 of embodiment 9 is described mainly with respect to the differences from the RFID tag 81 of embodiment 6. In the description of embodiment 9, elements having the same structure, action, and function as those of the aforementioned embodiment 6 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0245] In the RFID tag 81 of the sixth embodiment, the first land pattern 6a and the second land pattern 6b are arranged in the width direction of the antenna substrate 5, while in the RFID tag 111 of the ninth embodiment, the first land pattern 6a and the second land pattern 6b are arranged in the long side direction of the antenna substrate 5. In addition, the second antenna element 83b is led out from the second land pattern 6b and extends in a meandering manner toward the other end in the long side direction of the antenna substrate 5. The other structures are substantially the same as those of the RFID tag 1 of the first embodiment.

[0246] Similarly, when a frequency higher than the communication frequency is received by the structure of Embodiment 9, eddy currents are generated in the inter-line capacitance patterns 85a and 85b to generate a magnetic field, so a part of the fed power is lost as magnetic field energy. In addition, the potential difference between the opposing parts 83c can be increased and then discharged to disconnect the first antenna element 83a, thereby preventing the entire RFID tag 111 from catching fire.

[0247] Implementation Method 10

[0248] Below, refer to Fig.23 Next, an RFID tag 141 as a wireless communication device according to a tenth embodiment of the present invention will be described. Fig.23 It is a top view showing the structure of the RFID tag 141 according to the tenth embodiment.

[0249] The RFID tag 141 of embodiment 10 is described with a focus on the differences from the RFID tag 91 of embodiment 7. In the description of embodiment 10, elements having the same structure, action, and function as those of the aforementioned embodiment 7 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0250] The RFID tag 141 in the embodiment 10 is formed with a meander-shaped antenna pattern 143 that meanders along the long side direction of the antenna substrate 5 from the first pad pattern 6a and the second pad pattern 6b, respectively. The amplitude direction of the meander-shaped antenna pattern 143 is, for example, parallel to the width direction of the antenna substrate 5. The antenna pattern 143 has a first antenna element 83a in a meander-shaped shape and a second antenna element 83d that is point-symmetrically arranged with the center of the RFIC package 2 as the approximate center with the first antenna element 83a. In addition, as long as the second antenna element 83d is a meander-shaped shape, the first antenna element 83a and the second antenna element 83d may also be line-symmetrical instead of point-symmetrical. The second antenna element 83d in a meander-shaped shape having a bend 83dc is extended from the second pad pattern 6b in a manner that eventually faces the other end in the long side direction (-X direction) of the antenna substrate 5.

[0251] The inter-line capacitance pattern 85 is formed between adjacent straight line portions of the first antenna element 83a. As in Embodiment 7, the inter-line capacitance pattern 85 includes three inter-line capacitance patterns 85a, 85c, and 85d, and the arrangement order is alternately arranged according to the amplitude of the meander of the first antenna element 83a. In addition, the inter-line capacitance pattern 85 is also formed between adjacent straight line portions 83da of the second antenna element 83d.

[0252] The RFID tag 141 in Embodiment 10 is suitable for being attached to a non-metallic product, for example. For example, in the case where the product is a lunch box, there is no metal part in the lunch box, so the communication characteristics of the RFID tag 141 having two serpentine antenna elements at the communication frequency are improved compared to the RFID tag having the wide portion 7. In addition, even if the RFID tag 141 receives a frequency higher than the communication frequency, eddy currents are generated in the inter-line capacitance patterns 85a, 85c, and 85d to generate a magnetic field, similarly to the RFID tag 91, so that part of the fed power is lost as magnetic field energy. In addition, the potential difference between the opposing portions 83c can be increased and then discharged to disconnect the first antenna element 83a, so that the entire RFID tag 141 can be prevented from catching fire.

[0253] Implementation Method 11

[0254] Below, refer to Fig.24 Next, an RFID tag 151 as a wireless communication device according to Embodiment 11 of the present invention will be described. Fig.24 It is an exploded perspective view showing the structure of the RFID tag 151 according to the eleventh embodiment.

[0255] The RFID tag 151 of embodiment 11 is described with a focus on the differences from the RFID tag 141 of embodiment 10. In the description of embodiment 11, elements having the same structure, action, and function as those of the aforementioned embodiment 10 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0256] The antenna substrate 5 of the RFID tag 141 of the tenth embodiment uses a flame-retardant antenna substrate 5 similarly to the antenna substrate 5 of the first embodiment, but in the eleventh embodiment, a conventional antenna substrate 153 and a flame-retardant base substrate 155 are provided to replace the flame-retardant antenna substrate 5 illustrated in the first embodiment. The base substrate 155 is attached to the lower surface of the antenna substrate 153 by means of an adhesive such as a double-sided tape. In addition, the other structures of the RFID tag 151 of the eleventh embodiment are the same as those of the RFID tag 141 of the tenth embodiment.

[0257] The antenna substrate 153 is, for example, a PET film, and may not be flame retardant. The thickness of the antenna substrate 153 is, for example, 38 μm. The base substrate 155 is flame retardant compared to the antenna substrate 153, for example, having a flame retardant property that is heat resistant to about 200° C. The base substrate 155 is, for example, a polyester film. The thickness of the base substrate 155 is, for example, about 25 μm to 50 μm.

[0258] In addition, the line width of the first antenna element 83a and the second antenna element 83d is, for example, 125μm. The resistance value of the first antenna element 83a from the first pad pattern 6a to the end is, for example, 5Ω to 15Ω. The resistance value of the second antenna element 83d is the same. Since the first antenna element 83a and the second antenna element 83d have such a resistance value, when a frequency higher than the communication frequency is received, it is easy to break the line at the opposing portion 83c. The line width of the inter-line capacitance patterns 85a, 85c and 85d is thinner than the first and second antenna elements 83a, 83d, for example, 100μm.

[0259] According to this structure, when the RFID tag 151 receives a frequency higher than the communication frequency, in the case of large energy, the antenna pattern 143 receives electromagnetic wave energy and the antenna pattern is overheated to a high temperature. In particular, the temperature is easily increased at a certain facing portion 83c. A part of the antenna that has become hot generates a tiny spark discharge, and a part of the antenna pattern 143 that has been overheated to a high temperature sublimates. The antenna substrate 153 adjacent to the antenna pattern 143 that has become hot due to the heat also melts or shrinks, thereby no longer maintaining the shape of the substrate and causing the antenna pattern 143 to be disconnected. The surrounding antenna substrate 153 that has been overheated to a high temperature melts or shrinks, and the base substrate 155 nearby does not burn but melts because it is flame retardant. The melted base substrate 155 covers the surrounding metal conductor of the antenna pattern 143 where the tiny spark discharge has occurred. Thus, even if the RFID tag 151 is bent due to deformation caused by discharge or heat and shrinks as a whole, the antenna pattern 143 after the disconnection is covered by a part of the melted base substrate 155 as an insulator, so that the antenna patterns 143 can be kept separated from each other, and the contact between the antenna patterns 143 can be suppressed. Thus, it is possible to prevent the antenna pattern that receives a frequency higher than the communication frequency from being reconstructed. In addition, the insulation between the wirings of the antenna pattern 143 can be maintained.

[0260] In the case where the base substrate 155 is not provided, when the non-flame retardant antenna base 153 melts and shrinks around the discharge point, the metal conductors constituting the antenna pattern 143 may contact each other. The antenna pattern that was originally unable to receive a frequency higher than the communication frequency due to a disconnection may form an antenna pattern with a new pattern due to contact. As a result, there is a concern that a part of the new antenna pattern can be discharged again so that a frequency higher than the communication frequency can be received again. In this way, there is a concern that the RFID tag 151 without the base substrate 155 may continuously discharge.

[0261] In the case of the RFID tag 151 of embodiment 11, the antenna substrate 153 can be made of an inexpensive film, and the base substrate 155 can also be made of an inexpensive heat-resistant film, so that cost reduction can be achieved. In addition, even if a portion of the antenna pattern 143 is discharged and the antenna substrate 153 around it melts, the melted base substrate 155 will wrap around the antenna pattern 143 after the disconnection, so the disconnection state can be maintained. Therefore, the antenna pattern 143 cannot receive a frequency higher than the communication frequency again. In addition, since the melted base substrate 155 wraps around the antenna pattern 143, even if the RFID tag 151 is deformed due to the heat obtained by melting, it is possible to prevent short circuit again and form a new antenna pattern. In addition, the raw material of the flame-retardant antenna substrate 5 illustrated in embodiment 1 can also be used as the base substrate 155.

[0262] Implementation Method 12

[0263] Below, refer to Fig.25 Next, an RFID tag 161 as a wireless communication device according to Embodiment 12 of the present invention will be described. Fig.25 It is a top view showing the structure of the RFID tag 161 according to the twelfth embodiment.

[0264] The RFID tag 161 of embodiment 12 is described with a focus on the differences from the RFID tag 91 of embodiment 7. In the description of embodiment 12, elements having the same structure, action, and function as those of the aforementioned embodiment 12 are denoted by the same reference numerals, and the description is sometimes omitted to avoid duplication.

[0265] When an RFID tag having a wide portion 7 is attached to a commodity, as in the RFID tag 161 of the twelfth embodiment, it is preferable that the overlapping area between the commodity and the RFID tag 161 is within the area of ​​the wide portion 7 (see Figure 3B ). In the RFID tag 161, the antenna pattern 83 is designed based on the dielectric constant of the antenna substrate 5 and the air. Therefore, when the RFID tag 161 is attached to the product in such a way that the area beyond the wide portion 7 overlaps the antenna pattern 83 side, the dielectric constant of a part of the antenna pattern 83 becomes a dielectric constant different from the dielectric constant originally assumed. As a result, an area is formed in which the received wavelength is shortened, thereby forming an area in which the electromagnetic wave energy is concentrated even at a frequency higher than the communication frequency.

[0266] For example, when the RFID tag 161 is attached to a product with a large dielectric such as ceramics so that the portion closer to the antenna pattern 83 than the area of ​​the wide portion 7 overlaps with the product, not only the frequency of the communication frequency of the RFID tag 161 is shifted, but also electromagnetic wave energy is concentrated. As a result, there is a concern that the area of ​​the RFID tag 161 overlapping with the dielectric may be overheated and concentrated due to the concentration of electromagnetic wave energy, thereby catching fire.

[0267] Therefore, the RFID tag 161 of the embodiment 12 is provided with a bending portion 165 and a cover portion 163 extending from the antenna substrate 5 in the direction opposite to the wide portion 7 in the long side direction, so as to facilitate knowing the pasting position to be pasted on the commodity. The bending portion 165 and the cover portion 163 are formed integrally with the antenna substrate 5. The bending portion 165 is formed with notches 165a at the outer edge in a manner facing the inner side in the width direction. The bending portion 165 has a folding line 167 along the width direction of the antenna substrate 5, and each end of the folding line 167 is connected to the notch 165a. In addition, a structure that is easy to fold, such as a V-groove, can be formed instead of the folding line 167.

[0268] The total length or diagonal length of the outer periphery of the wide portion 7 is designed to be shorter than 1 / 4 wavelength of a certain specific frequency higher than the communication frequency. For example, when designed to be shorter than 1 / 4 wavelength of the wavelength of the frequency of an electromagnetic wave heating device (microwave oven), the size of the wide portion 7 is, for example, 10 mm in length La in the long side direction and 18 mm in length Lb in the width direction.

[0269] Although the end of the wide portion 7 on the antenna pattern 83 side is allowed as the attachment position to the product, if the antenna pattern 83 side is attached to the product at all, a frequency shift will occur. Therefore, for example, a length of 10% of the length La, that is, a length of 1 mm, can be set as a safety margin length La2, and the remaining 9 mm can be set as the length La1 in the long side direction of the product. A straight line along the width direction of the antenna substrate 5 at a position away from the end of the wide portion 7 on the antenna pattern 83 side by the length La2 is set as the attachment line ML to the product.

[0270] The cover portion 163 is formed to have such a size that when the cover portion 163 is bent along the folding line 167 so as to cover the antenna pattern 83, the end side of the cover portion 163 on the opposite side of the bending portion 165 just overlaps with the mounting line ML. A double-sided tape is attached to the entire surface of the RFID tag 161, and when the cover portion 163 is bent along the folding line 167, the cover portion 163 is attached to the antenna pattern 83.

[0271] Fig.26FIG. 1 is a top view of the RFID tag 161 after the cover 163 is bent along the folding line 167. The end edge of the cover 163 is located exactly at the mounting line ML, so the area of ​​the width 7 with a length La2 is covered by the cover 163, and the area of ​​the width 7 with a length La1 is exposed. Fig. 27 By attaching the end edge of the cover 163 along the end of a commodity such as a metal can 14 as shown, the RFID tag 161 can be appropriately attached to the commodity in a manner that avoids frequency shift.

[0272] In addition, the RFID tag 161 may not have the cover portion 163 and the bent portion 165 as described above, but an adhesive may be applied to the surface of the RFID tag 161 on the side opposite to the antenna pattern 83 side from the mounting line ML, and only the precautions such as the mounting line ML being attached along the end of the product may be written in advance on the back side of the RFID tag 161. In addition, symbols such as arrows may be used to easily indicate attachment using the mounting line ML.

[0273] Implementation Method 13

[0274] Next, an RFID tag 168 as a wireless communication device according to Embodiment 13 of the present invention will be described. The RFID tag 168 according to Embodiment 13 will be described with a focus on the differences from the RFID tag 81 according to Embodiment 6. In the description of Embodiment 13, elements having the same structure, function, and function as those in Embodiment 6 are denoted by the same reference numerals, and descriptions thereof are sometimes omitted to avoid duplication.

[0275] The RFID tag 168 of the thirteenth embodiment is greatly different from the RFID tag 81 of the sixth embodiment in the shape of the meander-shaped antenna pattern 169 . Fig.32 1 is a plan view showing the structure of RFID tag 168 according to Embodiment 13. RFID tag 168 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the UHF band, and is configured to be capable of wireless communication in a wide band.

[0276] In the RFID tag 168 of the thirteenth embodiment, the top view shape of the RFID tag 168 is formed to be more slender than the RFID tag 81 of the sixth embodiment, and the RFIC package 2 is installed in the center. That is, the antenna substrate 170 of the RFID tag 168 has a slender shape, and the antenna pattern 169 (the first antenna element 169a and the second antenna element 169b) are provided on both sides of the RFIC package 2 installed in the center of the antenna substrate 170. The first antenna element 169a is formed in a region on one side in the long side direction of the antenna substrate 170 (at Fig.32On the other hand, the second antenna element 169b is formed in the region on the other side of the long side of the antenna substrate 170 (in the region on the right side). Fig.32 The left side area is shown in the middle), and it extends in a winding manner toward the other end in the long side direction.

[0277] In the RFID tag 168 of the thirteenth embodiment, the line capacitance pattern 171 is arranged to generate capacitance between the adjacent folding portions 169ac and the folding portions 169bc in the meandering first antenna element 169a and the second antenna element 169b. Therefore, in the RFID tag 168 of the eighth embodiment, the folding portion 169ac and the folding portion 169bc correspond to the facing portion 83c of the RFID tag 81 of the sixth embodiment. In this way, in the RFID tag 168 of the thirteenth embodiment, a plurality of LC parallel resonant circuits S are formed along the respective paths of the first antenna element 169a and the second antenna element 169b having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter". In each of the plurality of LC parallel resonant circuits S of the thirteenth embodiment, it is also arranged to resonate with respect to the frequency of the 2.4 GHz to 2.5 GHz band used by the "microwave oven". In addition, the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength (λ / 2) of the frequency band (2.4 GHz to 2.5 GHz) of the heating electromagnetic wave.

[0278] The RFID tag 168 of the thirteenth embodiment has a simple structure of a small, narrow band, and can thus construct an easy-to-use and low-cost wireless communication device.

[0279] Fig.33 The modification of the thirteenth embodiment is a top view showing the structure of an RFID tag 172 in which the RFIC chip 9 is mounted on an antenna pattern 173. The RFID tag 172 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the UHF band, and is configured to be capable of wireless communication in a wide frequency band. Fig.33 In the RFID tag 172 shown, the RFIC chip 9 is mounted on the antenna pattern 169 formed in the loop portion 177, and other than this structure, it has the same Fig.32The RFID tag 172 has the same structure as the RFID tag 168 shown in the figure. That is, the antenna substrate 174 of the RFID tag 172 has an elongated shape, and the antenna pattern 173 (the first antenna element 173a and the second antenna element 173b) is provided on both sides of the loop portion 177 formed in the center of the antenna substrate 174. In the RFID tag 172, the line capacitance pattern 175 is provided so as to generate capacitance between the adjacent folded portions 173ac and between the folded portions 173bc in the meandering first antenna element 173a and the second antenna element 173b. In the RFID tag 172, a plurality of LC parallel resonant circuits S are also formed along the respective paths of the first antenna element 173a and the second antenna element 173b having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter".

[0280] exist Fig.33 Each of the multiple LC parallel resonant circuits S of the RFID tag 172 shown is also set to resonate with the frequency of the frequency band of 2.4GHz to 2.5GHz used by the "microwave oven", and the line length in each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength (λ / 2) of the frequency band of the heating electromagnetic wave (2.4GHz to 2.5GHz).

[0281] thus, Fig.33 The RFID tag 172 shown has a narrow band shape, making it a wireless communication device that is easy to use and not obtrusive to buyers in product displays.

[0282] As described above, in the RFID tags 168 and 172 of embodiment 13, even when the goods with the RFID tags 168 and 172 are heated by the medium in the electromagnetic wave heating device (microwave oven), the risk of fire in the RFID tags 168 and 172 can be prevented. The RFID tags 31 and 41 are easy-to-use wireless communication devices that are highly safe and reliable and do not interfere with the display of goods.

[0283] In the RFID tags 168 and 172 described in the thirteenth embodiment, the corner portions of the antenna patterns 169 and 173 and the line capacitance patterns 171 and 175 are configured to have curved surface shapes in order to suppress the concentration of the electric field.

[0284] Implementation Method 14

[0285] Next, an RFID tag 181 as a wireless communication device according to Embodiment 14 of the present invention will be described. The RFID tag 181 according to Embodiment 14 will be described with a focus on the differences from the RFID tag 81 according to Embodiment 6. In the description of Embodiment 14, elements having the same structure, function, and function as those in Embodiment 6 are denoted by the same reference numerals, and descriptions thereof are sometimes omitted to avoid duplication.

[0286] Fig.34A 1 is a plan view showing the structure of an RFID tag 181 according to Embodiment 14. The RFID tag 181 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and is configured to be capable of wireless communication in a wide band. Fig.34B This is a diagram showing the configuration of an antenna pattern (coil pattern) 183 in an RFID tag 181 according to Embodiment 14 using an equivalent circuit. Here, the HF band refers to a frequency band of 13 MHz to 15 MHz.

[0287] like Fig.34A As shown, the RFID tag 181 has an antenna pattern 183, and the antenna pattern 183 has a matching circuit of a loop portion 187 provided with an RFIC chip 9 and a capacitor element 182. In addition, in the matching circuit of the loop portion 187, the capacitor element 182 is connected at a position facing the RFIC chip 9. The antenna element 183a of the antenna pattern 183 in the RFID tag 181 extends from the loop portion 187 and is formed in a spiral shape. Fig.34A In the antenna element 183a shown, the antenna element 183a is led out in a manner of winding inward in the clockwise direction from the loop portion 187. The terminal portion of the antenna element 183a, which is the lead-out end portion, is directly connected to the matching circuit of the loop portion 187 via the bridge pattern 186. In addition, an insulating pattern 188 formed of a heat-resistant electrical insulating material is provided between the bridge pattern 186 and the antenna pattern 183, thereby ensuring the insulation state between the bridge pattern 186 and the antenna pattern 183.

[0288] In the spiral antenna element 183 a led out from the matching circuit of the loop portion 187 , a plurality of line capacitance patterns 185 for generating capacitance between adjacent paths are provided at predetermined intervals along the path of the antenna element 183 a .

[0289] A ring-shaped shield pattern 189 is formed inside the antenna element 183a. The shield pattern 189 is formed of a conductive material such as aluminum foil or copper foil, similar to the antenna pattern 183. The shield pattern 189 is a completely closed ring, but may be a partially interrupted shield pattern.

[0290] As described above, in the RFID tag 181 of the fourteenth embodiment, a plurality of LC parallel resonant circuits S are formed along the path of the antenna element 183a having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter". In each of the plurality of LC parallel resonant circuits S of the RFID tag 181, it is also set to resonate with a frequency in the frequency band of 2.4 GHz to 2.5 GHz used by the "microwave oven", and the line length in each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength (λ / 2) of the frequency band of the heating electromagnetic wave (2.4 GHz to 2.5 GHz).

[0291] In the RFID tag 181 of the fourteenth embodiment, the antenna pattern 183 and the line capacitance pattern 185 are stacked on the surface of the antenna substrate 184. In addition, on the surface of the antenna substrate 184, a bridge pattern 186 is formed on the antenna pattern 183 via an insulating pattern 188, thereby constituting the antenna in the RFID tag 181. Therefore, it is a structure in which a plurality of patterns (183, 185, and 186) are formed on the same surface of the antenna substrate 55, thereby making it easy to manufacture the RFID tag 51. In addition, in the RFID tag 181 of the fourteenth embodiment, the antenna substrate 184 does not need to be composed of a dielectric, and can be composed of, for example, a paper material.

[0292] As in the above-mentioned embodiment 6, Fig.19C As described above, in the RFID tag 181 of the fourteenth embodiment, a circuit structure is also formed that can significantly attenuate the frequency of the bandwidth of the heating frequency (2.4 GHz to 2.5 GHz) by using a "band rejection filter" composed of a plurality of LC parallel resonant circuits S. Therefore, in the RFID tag 181 as a wireless communication device of the fourteenth embodiment, a structure is formed that can perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and the following structure is formed: even when the dielectric of the commodity with the RFID tag 181 is heated in an electromagnetic wave heating device (microwave oven), the occurrence of discharge in the RFID tag 181 is significantly suppressed, thereby reliably preventing the danger of fire in the commodity.

[0293] Implementation Method 15

[0294] Next, an RFID tag 191 as a wireless communication device according to Embodiment 15 of the present invention will be described. The RFID tag 191 according to Embodiment 15 will be described with a focus on the differences from the RFID tag 81 according to Embodiment 6. In the description of Embodiment 15, elements having the same structure, function, and function as those in Embodiment 6 are denoted by the same reference numerals, and descriptions thereof are sometimes omitted to avoid duplication.

[0295] Fig.35A It is a plan view showing the structure of RFID tag 191 according to Embodiment 15. RFID tag 191 is configured to perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and is configured to be capable of wireless communication in a wide band. Fig.35B This is a diagram showing the structure of two coil patterns (193, 203) including an antenna pattern in the RFID tag 191 according to the tenth embodiment using an equivalent circuit.

[0296] like Fig.35A As shown, in the RFID tag 191 of the fifteenth embodiment, a resonant boost circuit having two coil patterns (193, 203) is configured. One of the coil patterns (primary side coil pattern) 203 in the RFID tag 191 has a matching circuit of a loop portion 200 provided with an RFIC chip 9 and a capacitor element 202. In the matching circuit of the loop portion 200, the RFIC chip 9 is connected to a position facing the capacitor element 202. The coil pattern (primary side coil pattern) 203 is led out from the loop portion 200 in a spiral shape, and the terminal portion of the coil pattern 73 as the lead-out end portion is directly connected to the matching circuit of the loop portion 200 via the bridge pattern 204. The coil pattern (primary side coil pattern) 203 is led out from the loop portion 200 in a manner of winding inward in the clockwise direction.

[0297] Furthermore, a bridge pattern 204 may be formed on the back side of the antenna substrate 194, and the terminal portion of the coil pattern (primary side coil pattern) 203 as the lead end portion may be connected to the loop portion 200 via an interlayer connection conductor that passes through the antenna substrate 194. Alternatively, in the case where the bridge pattern 204 is formed on the front side of the antenna substrate 194, the following structure may be used: an insulating pattern formed of a heat-resistant electrical insulating material is provided between the bridge pattern 204 and the primary side coil pattern 203, thereby ensuring the insulation state between the bridge pattern 204 and the primary side coil pattern 203.

[0298] In addition, the antenna pattern 193, which is another coil pattern (secondary coil pattern) in the RFID tag 191 of Embodiment 15, is formed to surround the coil pattern (primary coil pattern) 203, and is composed of an antenna element 193a formed in a manner of winding inward in the clockwise direction. In the spiral antenna element 193a of the antenna pattern 193, a plurality of line capacitance patterns 195 for generating capacitance between adjacent paths are arranged at predetermined intervals along the path of the antenna element 193a.

[0299] The antenna pattern 193 and the line capacitor pattern 195 in the RFID tag 191 of the fifteenth embodiment are formed on the surface of the antenna substrate 194. In addition, the capacitor element 192 is provided on the antenna element 193a of the antenna pattern 193. The outer end and the inner end of the spiral antenna element 193a are directly electrically connected via the interlayer connection conductor 196 penetrating the antenna substrate 194 and through the conductive path pattern 197 formed on the back surface of the antenna substrate 194.

[0300] A ring-shaped shield pattern 199 is formed inside the antenna element 193a. The shield pattern 199 is formed of a conductive material such as aluminum foil or copper foil, similar to the antenna pattern 193. The shield pattern 199 is a completely closed ring, but may be a partially interrupted shield pattern.

[0301] As described above, in the RFID tag 191 of the fifteenth embodiment, a plurality of LC parallel resonant circuits S are formed along the path of the antenna element 193a of the antenna pattern 193 having an inductance component, and these LC parallel resonant circuits S constitute a "band rejection filter". In each of the plurality of LC parallel resonant circuits S of the RFID tag 191, it is also set to resonate with the frequency of the frequency band of 2.4 GHz to 2.5 GHz used by the "microwave oven". In addition, the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength (λ / 2) of the frequency band of the heating electromagnetic wave (2.4 GHz to 2.5 GHz).

[0302] The RFID tag 191 of the embodiment 15 constructed as described above is a circuit structure that can significantly attenuate the frequency of the bandwidth of the heating frequency (2.4 GHz to 2.5 GHz) by using a "band rejection filter" composed of a plurality of LC parallel resonant circuits S. Therefore, in the RFID tag 191 as a wireless communication device of the embodiment 15, it is a structure that can perform wireless communication using a high-frequency signal having a communication frequency (carrier frequency) in the HF band, and has the following structure: even when the dielectric of the commodity with the RFID tag 191 is heated in an electromagnetic wave heating device (microwave oven), the occurrence of discharge in the RFID tag 191 is significantly suppressed, thereby reliably preventing the risk of fire in the commodity.

[0303] Implementation Method 16

[0304] Next, an RFID tag 211 as a wireless communication device according to Embodiment 16 of the present invention will be described. The RFID tag 211 according to Embodiment 16 will be described with a focus on the differences from the RFID tag 1 according to Embodiment 1. In the description of Embodiment 16, elements having the same structure, function, and function as those in Embodiment 1 are denoted by the same reference numerals, and descriptions thereof are sometimes omitted to avoid duplication.

[0305] In the RFID tag 211 of embodiment 16, the difference from the RFID tag 1 of embodiment 1 is that the line-to-line capacitance pattern 214 serving as a capacitance coupling portion is formed on the same plane (surface) as the antenna pattern 3, and the other structures are substantially the same as those of the RFID tag 1 of embodiment 1. Fig.36 It is a top view showing the structure of the RFID tag 211 of the sixteenth embodiment.

[0306] The inter-line capacitance pattern 214 has a first inter-line capacitance electrode 214a in a wide plate shape and a second inter-line capacitance electrode 214b in a narrow plate shape. The wide first inter-line capacitance electrode 214a capacitively couples specific opposing regions 3aa in the meandering first antenna element 3a, and similarly capacitively couples specific opposing regions 3ba in the meandering second antenna element 3b. The first inter-line capacitance electrode 214a is arranged to capacitively couple at least adjacent folded portions 3ac and 3bc in the first antenna element 3a and the second antenna element 3b, respectively.

[0307] On the other hand, the narrow second inter-line capacitor electrode 214b is configured to capacitively couple a specific area in the first antenna element 3a with a specific area in the second antenna element 3b. In addition, the narrow second inter-line capacitor electrode 214b is configured to capacitively couple the first pad pattern 6a with a specific area in the first antenna element 3a, and is also configured to capacitively couple the second pad pattern 6b with a specific area (including the wide portion 7) in the second antenna element 3b.

[0308] The first inter-line capacitor electrode 214a capacitively couples the opposing regions 3aa in the first antenna element 3a, forming a loop circuit consisting of the first inter-line capacitor electrode 214a and a part of the first antenna element 3a. This loop circuit is an LC parallel resonant circuit S. The second inter-line capacitor electrode 214b capacitively couples the opposing regions 3ba in the second antenna element 3b, forming a loop circuit consisting of the second inter-line capacitor electrode 214b and a part of the second antenna element 3b. The LC parallel resonant circuit S is formed by this loop circuit.

[0309] Each LC parallel resonant circuit S among the multiple LC parallel resonant circuits S is set to resonate with a frequency in the frequency band of 2.4 GHz to 2.5 GHz, and the line length of each LC parallel resonant circuit S is set to be shorter than 1 / 2 wavelength of the frequency used as the prescribed communication frequency and shorter than 1 / 2 wavelength (λ / 2) of the frequency band of the heating electromagnetic wave (2.4 GHz to 2.5 GHz).

[0310] In the RFID tag 211 of embodiment 16 constructed as described above, even when the product with the RFID tag 211 is heated by a medium in an electromagnetic wave heating device (microwave oven), the risk of fire in the RFID tag 211 can be prevented. The RFID tag 211 is a wireless communication device with high safety and reliability.

[0311] The present invention is not limited to the above-described embodiments, and can be implemented in the following modified forms.

[0312] (1) In the above-mentioned first embodiment, the facing region of the first antenna element 83a is the straight line portion 83aa, but the present invention is not limited thereto. For example, when the first antenna element 83a is formed in a curved shape, the line capacitance pattern 85 may be arranged between the curved antenna patterns facing each other. In addition, even when the facing region of the first antenna element 83a is the straight line portion 83aa, the straight line portions 83aa may not be arranged in parallel, but one straight line portion 83aa may be arranged obliquely with respect to another straight line portion 83aa.

[0313] (2) In the RFID tag of each embodiment, in the conductor patterns such as the antenna pattern and the line capacitance pattern, corner portions and the like are configured as smooth curved surfaces in order to suppress the concentration of the electric field.

[0314] Although the invention has been described in various embodiments with a certain degree of detail, it should be understood that the disclosure of these embodiments may vary in structural details, and changes in the combination and order of elements in each embodiment can be implemented without departing from the scope and concept of the claimed invention.

[0315] Industrial Applicability

[0316] The wireless communication device of the present invention as a commodity is a highly versatile and practical product, and the present invention is particularly needed when realizing an "unmanned convenience store".

[0317] Description of Reference Numerals

[0318] 1: RFID tag; 2: RFIC package; 3: antenna pattern; 3a: first antenna element; 3b: second antenna element; 4: line capacitor pattern (capacitive coupling part); 4a: first line capacitor electrode (wide shape); 4b: second line capacitor electrode (narrow shape); 5: antenna substrate; 6: pad pattern; 6a: first pad pattern; 6b: second pad pattern; 7: wide part; 8: lunch box; 9: RFIC chip; 10: inductor element; 11: external connection terminal; 11a: first external connection terminal; 11b: second external connection terminal; 12: insulating sheet; 13: through hole; 14: metal can; 81: R FID tag; 83: antenna pattern; 83a: first antenna element; 83ab: extension portion; 83b: second antenna element; 83c: facing portion; 83d: second antenna element; 85: line capacitance pattern; 85a: line capacitance pattern; 85b: line capacitance pattern; 85c: line capacitance pattern; 85d: line capacitance pattern; 87: shielding pattern; 87a: first shielding pattern; 91: RFID tag; 111: RFID tag; 141: RFID tag; 143: antenna pattern; 151: RFID tag; 153: antenna substrate; 155: base substrate; 161: RFID tag; 1 63: cover; 164: antenna substrate; 165: bending portion; 165a: notch; 167: folding line; 168: RFID tag; 169: antenna pattern; 169a: first antenna element; 169b: second antenna element; 170: antenna substrate; 171: line capacitance pattern; 172: RFID tag; 173: antenna pattern; 173a: antenna element; 174: antenna substrate; 175: line capacitance pattern; 177: loop; 181: RFID tag; 182: capacitor element; 183: antenna pattern; 183a: antenna element; 184: antenna substrate; 185: line capacitance pattern 186: bridge pattern; 187: loop portion; 188: insulating pattern; 189: shielding pattern; 191: RFID tag; 192: capacitor element; 193: antenna pattern; 193a: antenna element; 194: antenna substrate; 195: line capacitance pattern; 196: interlayer connecting conductor; 197: conductive path pattern; 198: insulating pattern; 199: shielding pattern; 200: loop portion; 202: capacitor element; 203: coil pattern; 204: bridge pattern; 211: RFID tag; 214: line capacitance pattern; 214a: first line capacitance electrode; 214b: second line capacitance electrode.

Claims

1. A wireless communication device for transmitting and receiving a high-frequency signal having a predetermined communication frequency, the wireless communication device comprising: an antenna pattern having facing areas facing each other; an RFIC element electrically connected to the antenna pattern; and A ring-shaped conductor pattern is arranged between each facing area of ​​the antenna pattern, in, The plurality of conductor patterns are arranged between the respective opposing regions of the antenna pattern at intervals from each other.

2. The wireless communication device according to claim 1, wherein: The antenna pattern is formed in a meandering shape, and each of the facing regions of the antenna pattern has straight line portions parallel to each other.

3. The wireless communication device according to claim 2, characterized in that The conductor pattern is arranged between adjacent folded portions of the antenna pattern.

4. The wireless communication device according to claim 1, wherein: The conductor pattern has a long side direction and a short side direction, and the length of the conductor pattern in the long side direction is formed to be less than or equal to 1 / 4 wavelength of a frequency used in electromagnetic wave heating.

5. The wireless communication device according to claim 1, wherein: When the antenna pattern is irradiated with electromagnetic waves having a frequency higher than the communication frequency, a potential difference increases between the respective facing regions of the antenna pattern between the plurality of conductor patterns.

6. The wireless communication device according to claim 1, characterized in that The conductor patterns having different circumferences are arranged along the straight line portion of the antenna pattern.

7. The wireless communication device according to claim 1, characterized in that A first resonant frequency obtained by the conductor pattern and a portion of the antenna pattern including the facing region sandwiched therebetween is different from a second resonant frequency obtained by another conductor pattern arranged next to the conductor pattern and another portion of the antenna pattern including the facing region sandwiched therebetween.

8. The wireless communication device according to claim 7, characterized in that: The first resonant frequency uses the frequency used in electromagnetic wave heating as the resonant frequency.

9. The wireless communication device according to claim 8, characterized in that The first resonance frequency has a frequency in a bandwidth of 2.4 GHz to 2.5 GHz as a resonance frequency, and the bandwidth of 2.4 GHz to 2.5 GHz is a frequency bandwidth used in electromagnetic wave heating.

10. The wireless communication device according to claim 7, characterized in that: A difference between a circumference of the conductor pattern and half a wavelength of the first resonance frequency higher than the communication frequency is smaller than a difference between a circumference of the conductor pattern and half a wavelength of the communication frequency.

11. The wireless communication device according to claim 1, wherein: A resin antenna substrate having the antenna pattern formed thereon is provided.

12. The wireless communication device according to claim 11, characterized in that A film is attached to the resin antenna substrate, and the flame retardancy of the film is higher than that of the antenna substrate.

13. The wireless communication device according to claim 1, wherein: The antenna pattern is configured to use the UHF band as a communication frequency.

14. The wireless communication device according to claim 1, wherein: The antenna pattern is configured to use the HF band as a communication frequency.

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