RFID tag and antenna pattern

Abstract

To provide an antenna pattern that can be manufactured easily and inexpensively while expanding the communication distance of radio waves and the direction and range in which radio waves can be transmitted and received.SOLUTION: An antenna pattern 1 includes a base material 10 and a strip-shaped dipole antenna 20 that is made of a conductive material and extends linearly, on a surface 10a of the base material 10. The dipole antenna 20 has a connection portion 25 which is located in the middle of the dipole antenna 20 in the longitudinal direction and to which an IC chip 3 is connected. A pair of long sides 21 of the dipole antenna 20 that are located at both ends of the dipole antenna 20 in the width direction and extend in the longitudinal direction of the dipole antenna 20 are each formed in a wave shape with a plurality of concave and convex shapes arranged in the longitudinal direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to RFID tags and antenna patterns. [Background technology]

[0002] Conventionally, RFID (Radio Frequency IDentification) technology, which allows for contactless writing and reading of large amounts of information wirelessly, has been used in a wide range of applications, including product identification and management, IT in offices and factories, and automation systems.

[0003] Patent Document 1 discloses an antenna pattern applied to UHF RFID, which includes a dipole antenna formed on the surface of a substrate and an antenna pattern having a sub-element formed on the back of the substrate. The antenna pattern of Patent Document 1 employs a dipole antenna including a meandering meander, thereby ensuring a longer radio communication distance while suppressing the size of the antenna pattern. Furthermore, the antenna pattern of Patent Document 1 has a sub-element in addition to the dipole antenna including the meander, thereby obtaining good gain not only in the direction intersecting the direction in which the dipole antenna extends, but also in the direction in which the dipole antenna extends. That is, the antenna pattern of Patent Document 1 improves directivity to expand the direction and range in which transmission and reception is possible, so that wireless communication in all directions can be performed well. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6941069 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the antenna pattern of Patent Document 1, it is necessary to form a sub-element in addition to the dipole antenna, which causes problems such as high costs (especially material costs) for manufacturing the antenna pattern and complicated manufacturing of the antenna pattern.

[0006] In view of the above-mentioned problems, an object of the present invention is to provide an antenna pattern that can be inexpensively and easily manufactured while expanding the communication distance and the direction and range in which radio waves can be transmitted and received, and an RFID tag equipped with the same. [Means for solving the problem]

[0007] One aspect of the present invention is an antenna pattern including a substrate and a strip-shaped dipole antenna formed of a conductive material on a surface of the substrate and extending linearly. The dipole antenna has a connection portion located at the middle of the dipole antenna in the longitudinal direction and connected to an IC chip. A pair of long sides of the dipole antenna, located at both ends in the width direction of the dipole antenna and extending in the longitudinal direction of the dipole antenna, are each formed in a wave shape with multiple concave and convex shapes arranged in the longitudinal direction.

[0008] One aspect of the present invention is an RFID tag including the antenna pattern and an IC chip connected to the connection portion. Effect of the Invention

[0009] According to the present invention, it is possible to easily manufacture an antenna pattern at low cost while increasing the communication distance and the directions and range in which transmission and reception are possible. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing an RFID tag including an antenna pattern according to a first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view taken along the line II-II in FIG. 1. [Diagram 3]FIG. 1 is a plan view showing a conventional RFID tag including an antenna pattern. [Figure 4] 11 is a plan view showing an RFID tag including an antenna pattern according to a second embodiment of the present invention. FIG. [Diagram 5] 11 is a plan view showing an RFID tag including an antenna pattern according to a third embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2, the RFID tag 100 of this embodiment is an antenna compatible with the UHF band, and includes an antenna pattern 1 and an IC chip 3. The IC chip 3 is connected to a connection portion 25 (described later) of the antenna pattern 1. Although not shown, the IC chip 3 may include a storage unit that stores various information such as identification information, a control unit for transmitting and receiving various information, and the like.

[0012] The antenna pattern 1 has a substrate 10 and a dipole antenna 20 . The substrate 10 is formed in a sheet or film shape. Examples of materials that can be used for the substrate 10 include papers such as fine paper and coated paper, resin films such as polyvinyl chloride, polyethylene terephthalate, polypropylene, polyethylene, and polyethylene naphthalate, and multilayer films formed by laminating a plurality of such resin films.

[0013] The dipole antenna 20 is formed of a conductive material on the front surface 10a of the substrate 10. The dipole antenna 20 has a strip shape that extends linearly on the front surface 10a of the substrate 10. 1 and 2, the X-axis direction corresponds to the longitudinal direction of the dipole antenna 20, and the Y-axis direction corresponds to the width direction of the dipole antenna 20. Moreover, the Z-axis direction in Fig. 1 and 2 corresponds to the thickness direction of the substrate 10 and the dipole antenna 20.

[0014] The strip-shaped dipole antenna 20 has a pair of long sides 21 (21-1, 21-2) and a pair of short sides 22. The pair of long sides 21 extend in the longitudinal direction at both ends of the width direction of the dipole antenna 20. The pair of short sides 22 extend in the width direction at both ends of the length direction of the dipole antenna 20. The pair of long sides 21 are each formed in a wave shape in which a plurality of concave and convex shapes that protrude and recess in the width direction of the dipole antenna 20 are arranged in the longitudinal direction. In this embodiment, the pair of short sides 22 extend linearly in the width direction. The pair of short sides 22 may be formed in a wave shape, for example.

[0015] In this embodiment, the corrugated shape of each long side 21 is formed by curved lines. Specifically, the corrugated shape is formed by convex curved lines. The corrugated shape of each long side 21 is formed by arranging a plurality of convex curved lines in the longitudinal direction. The corrugated shape of each long side 21 of the dipole antenna 20 is not limited to a convex curve, but may be, for example, a concave curve. The corrugated shape is not limited to a curve, but may be, for example, a straight line (broken line). When the corrugated shape is made up of straight lines, the convex portions of the corrugated shape may be, for example, triangular or rectangular.

[0016] In this embodiment, the wave shape of the pair of long sides 21 is formed in line symmetry with respect to a center line C1 extending in the longitudinal direction at the middle of the dipole antenna 20 in the width direction. Therefore, the positions of the apexes 23 of the convex portions in the longitudinal direction of the uneven shape coincide with each other between the pair of long sides 21. In other words, the dipole antenna 20 is formed in a shape like a standing wave by the pair of wave-shaped long sides 21. The dipole antenna 20 has an "antinode" portion having the largest dimension in the width direction and a "node" portion having the smallest dimension in the width direction. Moreover, the pair of short sides 22 of the dipole antenna 20 are located corresponding to the apexes 23 of the convex portions of the pair of long sides 21. In other words, the pair of short sides 22 are located corresponding to the "antinodes" of the dipole antenna 20 formed in a standing wave-like shape. Therefore, the length of the pair of short sides 22 is equal to the maximum dimension of the dipole antenna 20 in the width direction.

[0017] In this embodiment, the number of convex portions (convex curves) constituting the corrugated shape differs between the pair of long sides 21. Specifically, the number of convex portions on the first long side 21-1 located on the Y-axis negative side of the pair of long sides 21 is one less than the number of convex portions on the second long side 21-2 located on the Y-axis positive side. The first long side 21-1 does not have a convex portion corresponding to one convex portion located in the middle of the second long side 21-2 in the longitudinal direction. In other words, the corrugated shape of the first long side 21-1 is divided in the middle in the longitudinal direction.

[0018] The dipole antenna 20 has a connection portion 25 to which the IC chip 3 is connected. The connection portion 25 is located in the middle of the dipole antenna 20 in the longitudinal direction. The connection portion 25 has a pair of terminals 251 located at a distance in the longitudinal direction. Each of the pair of terminals 251 is connected to an electrode (not shown) of the IC chip 3. The connection portion 25 is located in a portion recessed inward (toward the positive Y-axis direction) from the first long side 21-1 of the dipole antenna 20 in the longitudinal middle portion. In other words, the position of the connection portion 25 corresponds to a position of the first long side 21-1 where no convex portion is formed.

[0019] In the dipole antenna 20, a slit 27 is formed inside the dipole antenna 20 in a plan view seen from the thickness direction of the substrate 10, extending in the longitudinal direction. The slit 27 extends line-symmetrically in the longitudinal direction from a middle portion in the longitudinal direction. The slit 27 is located adjacent to the connection portion 25 in the width direction. Specifically, the slit 27 is located adjacent to the connection portion 25 on the positive side of the Y-axis. The slit 27 constitutes a matching circuit that adjusts the impedance in the antenna pattern 1. The impedance can be adjusted by adjusting the length of the slit 27 in the longitudinal direction.

[0020] In this embodiment, the dimension (antenna length) of the dipole antenna 20 in the longitudinal direction is set to a half wavelength (λ / 2) of the design frequency. That is, the dipole antenna 20 is a half-wavelength dipole antenna. Note that the "design frequency" in this embodiment is a frequency in the UHF band. Since the dipole antenna 20 is a half-wave dipole antenna, the dipole antenna 20 and the transmitted radio wave are in a resonant state, and the maximum power can be received.

[0021] In the antenna pattern 1 of this embodiment and the RFID tag 100 including the same, a pair of long sides 21 of the dipole antenna 20 are formed in a wave shape. This makes it possible to expand the communication distance and the direction and range in which radio waves can be transmitted and received (expand the communication area). Furthermore, even if a sub-element is not provided on the back surface 10b of the substrate 10 as in the antenna pattern 1 of Patent Document 1, it is possible to expand the communication distance and the direction and range in which radio waves can be transmitted and received. Therefore, the antenna pattern 1 can be manufactured easily and inexpensively.

[0022] In addition, in the antenna pattern 1 of this embodiment, the pair of long sides 21 of the dipole antenna 20 are formed in a wave shape. Therefore, compared with the case where the pair of long sides 21 are formed in a straight line in the longitudinal direction, the length of the periphery (outer periphery) of the dipole antenna 20 including the pair of long sides 21 and the short side 22 can be increased without changing the size of the dipole antenna 20. Here, the length of the periphery (outer periphery) of the dipole antenna 20 is related to the frequency of radio waves that can be transmitted and received in the antenna pattern 1. Specifically, the lower the frequency of the radio waves to be transmitted and received in the antenna pattern 1, the longer the length of the periphery (outer periphery) of the dipole antenna 20 needs to be. In other words, the longer the length of the periphery (outer periphery) of the dipole antenna 20, the lower the frequency of the radio waves that can be easily transmitted and received (the resonant frequency of the antenna pattern 1). In addition, the greater the number of uneven shapes that form the wave shape of the long side 21, the lower the frequency of the radio waves that can be easily transmitted and received (the resonant frequency of the antenna pattern 1). For this reason, in the antenna pattern 1 of this embodiment, radio waves in a lower frequency band can be transmitted and received without changing the size of the dipole antenna 20. In other words, it is possible to miniaturize the antenna pattern 1 capable of transmitting and receiving radio waves at a desired frequency.

[0023] In addition, in the antenna pattern 1 of this embodiment, the pair of short sides 22 of the dipole antenna 20 are positioned to correspond to the vertices 23 of the convex portions of the pair of long sides 21, so that the length of the pair of short sides 22 can be made the longest. This makes it easier for the dipole antenna 20 to transmit and receive radio waves in the direction in which the short sides 22 face (the longitudinal direction). That is, the dipole antenna 20 can perform good wireless communication even in the longitudinal direction.

[0024] In addition, in the antenna pattern 1 of this embodiment, the concave and convex shapes constituting the wave shape of each long side 21 are formed by curves. Therefore, the length of the periphery (outer periphery) of the dipole antenna 20 can be made longer compared to a case where the concave and convex shapes are formed only by straight lines (broken lines). This makes it possible to further expand the communication area of ​​radio waves.

[0025] In addition, in the antenna pattern 1 of this embodiment, the uneven shape constituting the corrugated shape of each long side 21 is formed by a convex curve. Therefore, when the dimensions of the dipole antenna 20 in the longitudinal direction and the width direction are the same, the area of ​​the dipole antenna 20 can be made larger than when the uneven shape is formed by a concave curve. This allows for better wireless communication.

[0026] Furthermore, in the antenna pattern 1 of this embodiment and the RFID tag 100 including the same, even if the RFID tag 100 is attached to an attachment object such as a dielectric material such as clothing, the frequency shift in which the resonant frequency (frequency peak) of the antenna pattern 1 shifts to the low frequency side can be suppressed to a small value. This point will be described below. The communication characteristics of an antenna pattern are strongly affected by the dielectric material adjacent to the antenna pattern, and the resonance frequency (frequency peak) is likely to shift to the lower frequency side depending on the dielectric constant characteristics of the material. Since the frequency bands available in each country, including Japan and Europe, are fixed, if the frequency characteristics of the antenna pattern change significantly due to the dielectric constant of the material, it becomes difficult to read the information on the RFID tag.

[0027] In contrast, in the RFID tag 100 including the antenna pattern 1 of this embodiment, the frequency shift of the antenna pattern 1 can be kept small, resulting in less influence from the dielectric constant of the adherend and making it easier to read the information on the RFID tag 100. Furthermore, since the frequency shift of antenna pattern 1 caused by the adherend, which is a dielectric, is small, it is possible to design an antenna suitable for various dielectrics (adherends) by changing only the matching circuit (length of slit 27) without changing the antenna length of dipole antenna 20. For example, by changing the length of slit 27, the resonant frequency (frequency peak) of antenna pattern 1 can be changed. Specifically, by increasing the length of slit 27, the resonant frequency (frequency peak) of antenna pattern 1 can be shifted to the lower frequency side.

[0028] Specific examples of the above-mentioned "dielectric" include water and resin, in addition to clothing. When the dielectric is water, a container containing water as the dielectric is an example of the above-mentioned "adherend". In the RFID tag 100 of this embodiment, the above-mentioned effects are sufficiently achieved even when the dielectric is water.

[0029] Furthermore, in the antenna pattern 1 of this embodiment and the RFID tag 100 equipped with the same, the RFID tag 100 is attached to multiple items that can be stacked, such as files, documents, books, comics, etc., and even if these multiple items are stacked, i.e., even if multiple RFID tags 100 are close to each other, the information of the multiple RFID tags 100 can be easily read and the oversight of RFID tags can be reduced.

[0030] The effect of the antenna pattern 1 of the embodiment shown in Fig. 1 (hereinafter referred to as the embodiment antenna 1) will be described below in comparison with a conventional antenna pattern 1Z (hereinafter referred to as the comparative antenna 1Z) shown in Fig. 3. The comparative antenna 1Z shown in Fig. 3 is configured by providing a loop wiring 30Z constituting a matching circuit and a dipole antenna 20Z connected to the loop wiring 30Z and extending line-symmetrically from the loop wiring 30Z on the surface 10a of the substrate 10. In the comparative antenna 1Z, the dipole antenna 20Z includes a meander 29Z. The comparative antenna 1Z configures a conventional RFID tag 100Z by mounting an IC chip 3 on the loop wiring 30Z.

[0031] (Influence of dielectric) The frequency characteristics were measured while the example antenna 1 and the comparative antenna 1Z were placed close to a dielectric (adherend). As a result, it was found that the example antenna 1 had a smaller resonant frequency (frequency peak) shift of about 60 MHz compared to the comparative antenna 1Z. This revealed that the example antenna 1 can reduce the frequency shift caused by the dielectric constant of the dielectric (adherend).

[0032] (Antenna directivity) The directivity of the example antenna 1 and the comparative antenna 1Z was evaluated when the antenna was rotated 360 degrees using a frequency of 920 MHz band, with the angle at which the polarization plane is horizontal to the long side 21 being 0 degrees. As a result, the example antenna 1 has a gain higher by about 4 dB at the minimum operating power compared to the comparative antenna 1Z at 90 degrees and 270 degrees at which the polarization plane is horizontal to the short side 22. Furthermore, at 90 degrees and 270 degrees, the communication distance of the comparative antenna 1Z was 0 m, but the communication distance of the example antenna 1 was 5 m. Thus, it became clear that the example antenna 1 can easily transmit and receive radio waves even in the longitudinal direction (the direction in which the short side 22 faces), and therefore can easily transmit and receive radio waves at any angle compared to the comparative antenna 1Z.

[0033] (Lamination performance) The stacking performance was evaluated when two types of RFID tags including the example antenna 1 and the comparative antenna 1Z were stacked. Specifically, for each of the example antenna 1 and the comparative antenna 1Z, the RFID tag was attached to the same location inside a book, and 10 books were stacked. The RFID tags attached to these 10 books were read by a handy reader to verify the read rates of the example antenna 1 and the comparative antenna 1Z. As a result, the read rate of the example antenna 1 was improved by 30% compared to the read rate of the comparative antenna 1Z. This revealed that the example antenna 1 has better stacking performance than the comparative antenna 1Z. In addition, the reading distances of the example antenna 1 and the comparative example antenna 1Z were verified by reading the RFID tags attached to the 10 books with a handy reader. As a result, when the radio wave output of the handy reader was set to 30 dBm, the reading distance of the example antenna 1 was approximately 30% longer than that of the comparative example antenna 1Z. This also made it clear that the example antenna 1 has better stacking performance than the comparative example antenna 1Z.

[0034] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 4. In the following description, configurations common to those already described will be given the same reference numerals and duplicated description will be omitted.

[0035] 4, an RFID tag 100D of the second embodiment includes an antenna pattern 1D and an IC chip 3, similar to the first embodiment. The antenna pattern 1D of the second embodiment includes a substrate 10 and a dipole antenna 20D, similar to the first embodiment. The second embodiment differs from the first embodiment in the waveform of a pair of long sides 21D (21D-1, 21D-2) of the dipole antenna 20D and the shape of a pair of short sides 22D.

[0036] In the second embodiment, the pair of long sides 21D are formed in a wave shape in which a plurality of concave and convex shapes that protrude and sink in the width direction (Y-axis direction) of the dipole antenna 20D are arranged in the longitudinal direction (X-axis direction) in the same manner as in the first embodiment. Moreover, the wave shape of the pair of long sides 21D is formed in line symmetry with respect to the center line C1. However, in the second embodiment, the concave-convex shape forming the wave shape of each long side 21D is a convex curve or a concave curve. The wave shape of each long side 21D is configured by arranging convex curves and concave curves alternately in the longitudinal direction. Therefore, the wave shape of each long side 21D is formed into a shape in which adjacent concave-convex shapes are smoothly connected.

[0037] In the second embodiment, each of the pair of short sides 22D is formed in a wave shape including a concave-convex shape that protrudes and recesses in the longitudinal direction of the dipole antenna 20D. In Fig. 4, the concave-convex shapes forming the wave shape of each short side 22D are arranged in a plurality of lines in the width direction. The concave-convex shapes are convex curves or concave curves. The wave shape of each short side 22D is formed by alternately arranging convex curves and concave curves in the longitudinal direction.

[0038] According to the antenna pattern 1D and the RFID tag 100D of the second embodiment, the same effects as those of the first embodiment are achieved. In addition, in the second embodiment in which the short side 22D of the dipole antenna 20D is formed in a wave-like shape, it is possible to obtain antenna performance (communication distance, frequency characteristics) similar to that of the first embodiment in which the short side 22 (see Figure 1) is formed in a straight line.

[0039] In the second embodiment, the corrugated shape of each short side 22D may be formed, for example, by only convex curves or only concave curves. The corrugated shape is not limited to curves, and may be formed, for example, by straight lines (broken lines). When the corrugated shape is formed by straight lines, the convex portions of the corrugated shape may be formed, for example, in a triangular or rectangular shape.

[0040] In the second embodiment, the number of concave and convex shapes constituting the wave shape of each short side 22D may be, for example, 1. That is, the wave shape of each short side 22D may be constituted by, for example, only one convex curve or one concave curve.

[0041] The wave shape of each long side 21D in the second embodiment is not limited to the shape exemplified in FIG. 4, and may be, for example, the shape exemplified in the first embodiment.

[0042] The corrugated shape of each long side 21D illustrated in FIG. 4 may be applied to the dipole antenna 20 of the first embodiment.

[0043] Third Embodiment Next, a third embodiment of the present invention will be described with reference to Fig. 5. In the following description, configurations common to those already described will be given the same reference numerals and duplicated description will be omitted.

[0044] As shown in Fig. 5, an RFID tag 100F of the third embodiment includes an antenna pattern 1F and an IC chip 3, similar to the first embodiment. The antenna pattern 1F of the third embodiment includes a substrate 10 and a dipole antenna 20F, similar to the first embodiment. The long side and short side of the dipole antenna 20F in the third embodiment may be formed into any of the shapes described in the first and second embodiments. The dipole antenna 20F illustrated in Fig. 5 has a long side 21D having the same shape as the second embodiment and a short side 22 having the same shape as the first embodiment.

[0045] In the third embodiment, a cavity 28F is formed inside the periphery of the dipole antenna 20F. The cavity 28F is formed penetrating the dipole antenna 20F in its thickness direction (Z-axis direction). The "periphery of the dipole antenna 20F" includes the pair of long sides 21D and the pair of short sides 22, as well as the edge of the connection portion 25 (terminal 251) continuing to the first long side 21D-1 and the inner edge of the slit 27 continuing to the edge of the connection portion 25. The shape and size of the cavity 28F as viewed in the thickness direction may be arbitrary. In the dipole antenna 20F illustrated in Fig. 5, the periphery of the cavity 28F is formed along the periphery of the dipole antenna 20F. Therefore, the dipole antenna 20F in Fig. 5 is formed in a strip shape (or ring shape) extending along the periphery of the dipole antenna 20F.

[0046] According to the antenna pattern 1F and the RFID tag 100F of the third embodiment, the same effects as those of the first embodiment are achieved. In addition, in the antenna pattern 1F of the third embodiment, the cavity 28F is formed inside the periphery of the dipole antenna 20F, so that the dipole antenna 20F can be formed with a smaller amount of material compared to a dipole antenna without the cavity 28F (e.g., the dipole antennas 20 and 20D illustrated in Figs. 1 and 4). For example, when the dipole antenna 20F is formed on the surface 10a of the substrate 10 by printing (e.g., screen printing), the amount of ink used for printing the dipole antenna 20F can be reduced. Therefore, the manufacturing cost of the dipole antenna 20F can be reduced. In addition, the dipole antenna 20F having the cavity 28F can ensure a maximum communication distance (communication distance at the frequency peak) equivalent to that of a dipole antenna without the cavity 28F.

[0047] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit of the present invention.

[0048] The RFID tag of the present invention is not limited to being compatible with the UHF band, but may be compatible with any frequency band. [Explanation of symbols]

[0049] 1,1D,1F Antenna Pattern 3. IC chip 10 Base material 10a surface 20, 20D, 20F dipole antenna 21,21D Long side 22,22D Short side 23 Vertex of convex part 25 Connection 27 Slit 28F Cavity 100, 100D, 100F RFID tags C1 center line

Claims

1. A substrate; a strip-shaped dipole antenna formed of a conductive material on a surface of the base material and extending linearly; the dipole antenna has a connection portion located in the middle of the dipole antenna in a longitudinal direction and to which an IC chip is connected; An antenna pattern in which a pair of long sides of the dipole antenna, located at both ends in the width direction of the dipole antenna and extending in the longitudinal direction of the dipole antenna, are each formed in a wave-like shape with multiple concave and convex shapes arranged in the longitudinal direction.

2. the corrugated shapes of the pair of long sides are formed to be axisymmetric with respect to a center line extending in the longitudinal direction at a middle of the dipole antenna in the width direction, 2. The antenna pattern according to claim 1, wherein a pair of short sides of the dipole antenna located at both ends in the longitudinal direction and extending in the width direction are positioned to correspond to vertices of convex portions of the concave-convex shape on the pair of long sides.

3. 3. The antenna pattern according to claim 1, wherein the uneven shape is formed by curved lines.

4. 3. The antenna pattern according to claim 1, wherein the concave-convex shape is formed by a convex curve.

5. 3. The antenna pattern according to claim 1, wherein a pair of short sides of the dipole antenna located at both ends in the longitudinal direction and extending in the width direction are each formed in a wavy shape including uneven shapes that protrude and recess in the longitudinal direction.

6. 3. The antenna pattern according to claim 1, wherein a cavity is formed inside a periphery of the dipole antenna.

7. The antenna pattern according to claim 1 or 2, and an IC chip connected to the connection portion.

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