JP4326936B2 - Wireless tag - Google Patents

Description

The invention, for example, relates an RFID (Radio Frequency Identification) wireless tag used like system.

  An RFID system is usually composed of a reader having a write / read function and a wireless tag. Conventionally, particularly in the microwave region, a tag incorporating a battery is often used as a wireless tag in the FA field or the like. Recently, due to the progress of semiconductors, batteryless tags that detect transmission radio waves from readers and use them as drive power to perform tag operations have appeared. In addition to FA, logistics, distribution, product history management, etc. Significant utilization / deployment is planned in the field (for example, see Patent Document 1).

  For example, as shown in FIG. 20, the RFID system is composed of a reader RW that also has a function of writing information data, a reader antenna RA, and a wireless tag T. The reader RW transmits a radio wave signal from the reader RW. The radio tag T receives the transmitted radio wave signal, reflects the input signal with the information stored in the memory in the tag, and returns it to the reader RW. The signal returned from the wireless tag T is demodulated by the reader RW to extract tag information.

  A typical example of a wireless tag used in the RFID system is shown in FIGS.

  A radio tag T20 shown in FIG. 21 is formed by forming a dipole antenna 201 that transmits and receives a signal as a radio wave on a dielectric substrate 202 and incorporating a tag IC 5 having a tag processing function. As the dielectric substrate 202 of the wireless tag T20, a thin dielectric substrate such as polypropylene or polyimide, or a glass epoxy substrate having a certain thickness is used. 21 indicates the direction of the electric field component E of the radio wave radiated from the dipole antenna 201.

  When a dipole antenna is applied to a wireless tag, the antenna length is set to about one wavelength or less in consideration of the sidelobe problem. Among them, the antenna length is generally set to about a half wavelength (λg / 2) of the equivalent wavelength λg of the communication frequency. The equivalent wavelength λg is shorter than the free space wavelength due to the effect of the dielectric constant (ε) of the dielectric substrate on which the antenna is mounted, and the wavelength is usually about 1 / √ε, although it depends on the thickness of the dielectric substrate. Shortened.

  The characteristic of a dipole antenna is that it has signal radiation characteristics over 360 degrees around the antenna axis in the length direction of the antenna. Therefore, communication with the reader antenna can be accessed from the direction around the antenna axis. An effective wireless tag can be configured for applications in which communication is performed from the direction.

By the way, when using a wireless tag, if an article is installed without being aware of the tag direction of the article attached with the wireless tag, if the communication with the wireless tag can be performed from all directions, the operation of reading the wireless tag is performed. The sex becomes very easy. However, since the dipole antenna does not have sensitivity in the axial direction, there is a problem in applications where communication is performed from all directions of the wireless tag.
No. 2003-249820

  As described above, in the past, as a wireless tag that can be easily manufactured, a system in which a tag IC is mounted on a half-wave dipole antenna is often used. However, a radio tag having a half-wave dipole antenna has its radio wave directivity radiated in all directions with respect to the antenna axis, but has no radiation sensitivity in the axial direction. For this reason, when communicating with a wireless tag mounted on an article, it is necessary to perform communication from a direction having communication sensitivity, which restricts the usage form of the wireless tag.

  Further, the conventional wireless tag cannot be used by attaching the dielectric thin film surface to a metal object or the like. That is, when a wireless tag is attached to a metal object, there cannot be an electric field component parallel to the metal surface, so a virtual electric field that cancels the parallel electric field component is generated, and radio wave emission from the wireless tag does not occur. Communication becomes impossible. Furthermore, since a length of about half a wavelength is required, it is not suitable when the space for small articles such as watches and precious metals, and objects for mounting wireless tags is small. For this reason, the conventional wireless tag has a problem that the range of use is restricted.

The present invention has been made in view of such circumstances, and communication is possible regardless of whether it is mounted on a non-metal object or a metal object, and the range of use is wide. and to provide good small wireless tag.

The wireless tag of the present invention includes a dielectric having upper and lower surfaces and side surfaces that are parallel or non-parallel to each other, and an upper surface antenna portion, a lower surface antenna portion, and a side antenna portion (for example, a side antenna portion) formed on the dielectric. Or a bar-shaped side antenna portion penetrating a dielectric) and a tag IC, and at least one upper surface antenna portion, lower surface antenna portion, and side antenna portion form one tag antenna, and the tag antenna The tag IC is connected and mounted between two electrode terminal portions formed by cutting off the middle portion of any one of the plurality of antenna portions forming the antenna portion (hereinafter simply referred to as “the tag IC ”). (It is also referred to as “the tag IC is mounted on the antenna portion”) .

  In the wireless tag of the present invention, it is preferable that the total conductor length of the tag antenna formed on the dielectric is approximately one wavelength or less (including approximately one wavelength) of the equivalent electrical length of the communication frequency including the tag IC. . Further, it is preferable that the tag IC is installed in the vicinity of approximately ¼ to ½ wavelength of the total equivalent electrical length from the end of the tag antenna.

  According to the wireless tag of the present invention, the tag antenna is constituted by at least the upper surface antenna portion, the lower surface antenna portion, and the side antenna portion, and the tag antenna has a three-dimensionally bent pattern. Miniaturization can be achieved compared to tags.

  Further, by utilizing the wavelength shortening effect of the radio wave signal due to the dielectric constant of the dielectric sandwiched between the upper surface antenna portion and the lower surface antenna portion, the propagation phase difference of the radio wave radiated from the upper surface and the lower surface of the dielectric is further increased. Since the signal wave radiated from the upper surface antenna portion and the lower surface antenna portion with opposite electric field components has a weaker cancellation effect, the radio wave radiation effect on the upper surface side and lower surface side of the dielectric can be enhanced. it can. In particular, if the distance between the upper surface antenna portion and the lower surface antenna portion is λg / 4 of the equivalent wavelength (λg), the radiation from the upper surface antenna portion and the lower surface antenna portion are in phase, and the radiation effect is maximized by adding the electric field components. It becomes. In addition, since radio waves are also radiated from the side antenna units, radio waves having electric field components are radiated in at least two directions (two axes) orthogonal to each other, and communication with the reader is possible from two different directions. Further, the size of the entire tag can be reduced by utilizing the wavelength shortening effect of the dielectric.

  In the wireless tag according to the present invention, the antenna portions are arranged so that a projection area obtained by projecting (vertically projecting) the upper surface antenna portion on the upper surface of the dielectric onto the lower surface and a formation area of the lower surface antenna portion on the lower surface are shifted from each other. Alternatively, if the projected shape obtained by projecting the top antenna portion on the top surface of the dielectric onto the bottom surface (vertical projection) and the shape of the bottom antenna portion on the bottom surface are different, the top antenna portion and the bottom antenna portion Radio waves having the same electric field direction are radiated in a lateral direction orthogonal to the radio wave radiation in the vertical direction. As a result, communication with the wireless tag by the reader is also possible from the lateral direction. As a result, the operability of communication is improved.

  In the wireless tag according to the present invention, a plurality of antenna parts forming the tag antenna, that is, at least one antenna part such as a top antenna part, a bottom antenna part, and a side antenna part is bent at a right angle (for example, an L-shaped pattern). If it is formed, it will have radio wave radiation characteristics in three directions (three axes) orthogonal to each other, including radio wave radiation from the side antenna section, and communication by the reader will be possible from three different directions. The operability is further improved.

In the wireless tag according to the present invention, the conductor length of the remaining antenna portion excluding the lower surface antenna portion from the plurality of antenna portions forming the tag antenna, that is, the upper surface antenna portion, the lower surface antenna portion, and the side portion antenna portion is defined as the tag IC. the comprise less substantially half-wavelength of the equivalent electrical length of the communication frequency (including substantially half-wavelength), preferably, when approximately 1/4 wavelength, when the stuck lower surface antenna unit to the metal object, the metal object side Since an image antenna is formed on the wireless tag and communication is possible, the wireless tag can be mounted on the metal object. That is, a wireless tag that does not depend on the mounted object can be realized, and the range of use can be greatly expanded.

  In the wireless tag of the present invention, if the tag IC matching circuit is formed on the tag antenna, impedance matching between the tag antenna and the tag IC is facilitated, and the performance of the tag IC can be effectively exhibited. it can. A specific configuration of the matching circuit may include a configuration in which a reactance component is formed by partially narrowing a conductor width of the tag antenna to form an impedance matching circuit of the tag IC.

  In the wireless tag of the present invention, a plurality of antenna parts constituting the tag antenna, that is, an upper surface antenna part, a lower surface antenna part, a side antenna part, etc. are provided with cuts or protrusions at the periphery of at least one antenna part. If the path of the current flowing through is lengthened, the wireless tag can be miniaturized.

  The wireless tag of the present invention includes a dielectric having two adjacent surfaces formed so as to form an acute angle or an obtuse angle, an antenna portion formed on each of the two surfaces of the dielectric, and a tag IC, One tag antenna is formed by at least two antenna portions formed on the two surfaces, and the tag IC is mounted on any one of the plurality of antenna portions forming the tag antenna. It is characterized by that.

  In the wireless tag of the present invention, it is preferable that the total conductor length of the tag antenna formed on the dielectric is approximately one wavelength or less (including approximately one wavelength) of the equivalent electrical length of the communication frequency including the tag IC. . Further, it is preferable that the tag IC is installed in the vicinity of approximately ¼ to ½ wavelength of the total equivalent electrical length from the end of the tag antenna.

  According to the wireless tag of the present invention, the tag antenna is configured by at least two antenna portions formed on the two surfaces of the dielectric, and the tag antenna is formed into a three-dimensionally bent pattern. Miniaturization can be achieved compared to tags. Further, the two antenna portions formed on the two surfaces of the dielectric are arranged such that the other antenna portion is inclined with respect to one of the antenna portions, so that radio waves having electric field components in at least two different directions (two axes). Is emitted, and communication with the reader becomes possible from two different directions.

  In the wireless tag according to the present invention, a projection area obtained by projecting (vertically projecting) an antenna portion on one of the two surfaces of the dielectric onto the other surface and an area where the antenna portion is formed on the other surface are mutually connected. Each antenna portion is arranged so as to be shifted to the other, or one of the two surfaces of the dielectric is projected onto the other surface (vertical projection), and the antenna on the other surface If the shape of the part is different, the radio wave is radiated in a direction different from the radio wave radiation direction of the two antenna parts, so that the operability of communication is improved.

In the wireless tag of the present invention, the remaining antenna portion excluding the lower surface antenna portion from the plurality of antenna portions forming the tag antenna, that is, the antenna portions formed on the two surfaces of the dielectric , that is, the conductor length of the upper surface antenna portion Includes the tag IC and is approximately equal to or less than a half wavelength (including a substantially half wavelength) of the equivalent electrical length of the communication frequency , and preferably approximately a quarter wavelength , the lower surface of the antenna portion formed on the two surfaces of the dielectric When the antenna portion is attached to a metal object, an image antenna is formed on the metal object side and communication is possible, so that the wireless tag can be mounted on the metal object. That is, a wireless tag that does not depend on the mounted object can be realized, and the range of use can be greatly expanded.

  In the wireless tag according to the present invention, when a plurality of antenna parts forming the tag antenna, that is, at least one antenna part such as two antenna parts is formed in a shape that bends at right angles (for example, an L-shaped pattern), Including radio wave radiation from the antenna section, it has radio wave radiation characteristics in three different directions (three axes), enabling communication by the reader from three different directions, further improving the operability of communication. .

  In the wireless tag of the present invention, if the tag IC matching circuit is formed on the tag antenna, impedance matching between the tag antenna and the tag IC is facilitated, and the performance of the tag IC can be effectively exhibited. it can. A specific configuration of the matching circuit may include a configuration in which a reactance component is formed by partially narrowing a conductor width of the tag antenna to form an impedance matching circuit of the tag IC.

  In the wireless tag of the present invention, a plurality of antenna portions forming the tag antenna, that is, two antenna portions, are provided with cuts or protrusions at the periphery of at least one antenna portion to lengthen the path of current flowing through the antenna surface. If this is done, the wireless tag can be miniaturized.

  The RFID system according to the present invention includes a wireless tag having the above-described characteristics and a reader that transmits a question signal to the wireless tag and receives a response signal from the wireless tag.

  According to the wireless tag of the present invention, the tag antenna is configured by a plurality of antenna portions formed on different surfaces, and the tag antenna has a three-dimensionally bent pattern. Therefore, compared to a normal dipole antenna type wireless tag, Miniaturization can be achieved.

In the wireless tag of the present invention, the conductor length of the remaining antenna portion excluding the bottom antenna portion from the plurality of antenna portions is less than or equal to approximately half wavelength of the equivalent electrical length of the communication frequency including the tag IC , preferably By setting the wavelength to about ¼ , the wireless tag can be mounted on the metal object. As a result, a wireless tag that does not depend on the mounted object can be realized, and the range of use can be greatly expanded. Furthermore, since it is possible to radiate radio waves having electric field components orthogonal to at least two directions (two axes) or three directions (three axes), communication by the reader is possible from two or three directions that are different. Operability is improved.

  By using a wireless tag having the characteristics described above, an RFID system with high communication reliability and excellent communication operability in various fields such as FA, logistics, distribution, product history management, etc. It becomes possible to build easily.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1>
FIG. 1 is a diagram illustrating a plan view (A) and a central longitudinal sectional view (B) showing an example of a wireless tag of the present invention. 2A and 2B are perspective views of the wireless tag in FIG. 1 as viewed from the upper surface side and the lower surface side, respectively.

  The RFID tag T0 in this example includes a rectangular parallelepiped (or thin substrate) dielectric 1 and an upper surface antenna portion 2, a lower surface antenna portion 3 formed on an upper surface 1a, a lower surface 1b, and a side surface 1c of the dielectric 1, respectively. A side antenna unit 4 and a tag IC 5 are provided.

  The top antenna unit 2 and the bottom antenna unit 3 are electrically connected by the side antenna unit 4, and the top antenna unit 2, the bottom antenna unit 3, and the side antenna unit 4 form one tag antenna AN. . The tag IC 5 is mounted on the upper surface antenna 2 and is electrically connected to the electrode terminal portion 2 a formed on the conductor end of the upper surface antenna portion 2. Further, as shown in the perspective view of FIG. 2, the lower surface antenna portion 3 is formed on the entire lower surface 1 b of the dielectric 1, and what is the upper surface antenna portion 2 formed on a part of the upper surface 1 a of the dielectric 1. The length and width are different.

  In the wireless tag T0 of this example, the tag antenna AN is configured by the upper surface antenna portion 2, the lower surface antenna portion 3, and the side surface antenna portion 4, and the tag antenna AN is a three-dimensionally bent pattern. The length including the antenna unit 2, tag IC 5, side antenna unit 4, and bottom antenna unit 3 is approximately λg / 2 of the equivalent electrical length (λg) of the communication frequency (λg is equivalent including the dielectric constant effect of the dielectric) Wavelength). Therefore, the length of the wireless tag T0 is approximately λg / 4, which is about 1/2 of the size of a normal dipole antenna type wireless tag.

  The length including the upper surface antenna portion 2, the tag IC 5, the side surface antenna portion 4, and the lower surface antenna portion 3 is approximately one wavelength or less (approximately one wavelength less than the equivalent electrical length of the communication frequency) in the same manner as a normal dipole antenna. May be included).

  Next, the operation of the wireless tag T0 will be described with reference to FIG.

  First, assuming that a radio wave signal transmitted from the reader RW (see FIG. 20) is received by the tag antenna AN of the wireless tag T0 of this example, reflected and modulated by the tag IC5, and transmitted from the tag IC5, the tag IC5 The signal wave from the resonance of the folded λg / 2 antenna excites the tag antenna AN.

  Here, in FIG. 3, the current flowing through the tag antenna AN turned back by the excitation of the tag IC 5 is indicated by a broken line I. The current I flowing through the tag antenna AN flows in the opposite direction between the upper surface antenna portion 2 and the lower surface antenna portion 3. As a result, the electric field directions of the radio waves induced and radiated by the current I are opposite to each other. That is, the electric field components of the signal waves radiated from the upper surface antenna portion 2 and the lower surface antenna portion 3 are as indicated by alternate long and short dash lines Ea and Ea 'in FIG. In addition, the electric field component of the signal wave radiated from the side antenna unit 4 is indicated by a one-dot chain line Ec. Note that there is no reverse component of the electric field component Ec by the side antenna unit 4.

  Next, in this wireless tag T0, radio wave radiation of the entire tag in the horizontal direction and vertical direction of the paper will be described.

  First, as described above, the signal waves of the reverse electric field components Ea and Ea ′ radiated from the upper surface antenna portion 2 and the lower surface antenna portion 3 are radiated in the left-right direction and the front-rear direction of the paper surface of FIG. The signal wave radiated from the entire wireless tag T0 is a composite wave thereof. However, since the electric field components of the signal waves radiated from the upper surface antenna unit 2 and the lower surface antenna unit 3 are opposite to each other, the electric field components of the signal waves in the left-right direction and the front-rear direction act in a direction to cancel each other.

  By the way, the signal wave propagating from the upper surface antenna portion 2 and the lower surface antenna portion 3 toward the inside of the dielectric 1 is subjected to the wavelength compression effect of the relative permittivity ε of the dielectric 1. A phase rotation corresponding to the equivalent electrical length λgε occurs. Such a wavelength compression effect increases as the dielectric constant increases, and is generally reduced to about 1 / √ε of the relative dielectric constant ε of the dielectric 1.

  As a result, the cancellation effect of the signal waves radiated from the upper surface antenna portion 2 and the lower surface antenna portion 3 is reduced, and the combined wave is radiated from the wireless tag T0 in the left-right direction on the paper surface of FIG. Furthermore, if the phase rotation due to the equivalent electrical length λgε corresponds to π, the signal waves radiated from the top antenna unit 2 and the bottom antenna unit 3 are in phase, and the electric field component is added to maximize the radiation effect.

  Note that the signal waves radiated in the front-rear direction (orthogonal direction) of the paper surface of FIG. 3 due to the electric field components Ea and Ea ′ work in the direction in which the electric field direction is opposite and cancels. As a result, only the difference between the combined waves of the electric fields Ea and Ea ′ is radiated in the front-rear direction of the page.

  As described above, by arranging the upper surface antenna portion 2 and the lower surface antenna portion 3 with the relatively thick dielectric 1 interposed therebetween, the signal wave radiation effect can be enhanced even if the entire tag is downsized.

  Further, even when the dielectric 1 is as thin as the substrate, the radiation efficiency can be increased. As the method, as shown in the perspective view of FIG. 2, a method of making the upper antenna portion 2 and the lower antenna portion 3 have patterns having different lengths and widths is effective. If such a method is adopted, the intensity of the signal wave radiated from the upper surface antenna unit 2 and the intensity of the signal wave radiated from the lower surface antenna unit 3 become different, so that cancellation of radiated signals that are opposite to each other in the electric field direction. The effect can be weakened. Moreover, the signal wave radiated | emitted from the side antenna part 4 has an electric field component shown with the dashed-dotted line Ec of FIG. 3 as mentioned above, and is radiated | emitted to the up-down direction and the front-back direction of the paper surface of FIG. Therefore, the radio tag T0 of this example can basically radiate radio waves in the horizontal direction and vertical direction of FIG.

  In the above example, with respect to the upper surface antenna portion 2 and the lower surface antenna portion 3 that are folded back by about λg / 2, the current of each antenna portion 2 and 3 flows in the vicinity of the edge thereof. When the antenna conductor width is increased, the overall length of the tag antenna AN can be shortened, and the wireless tag T0 can be further reduced in size.

  Here, in the example of FIG. 1, the side surface antenna portion 4 is formed on one side surface 1 c of the dielectric 1, and the upper surface antenna portion 2 and the lower surface antenna portion 3 are connected by this side surface antenna portion 4. The invention is not limited to this, and for example, as shown in FIGS. 4A and 4B, a rod-shaped side antenna portion 6 that penetrates the thickness direction of the dielectric 1 is provided, and this side antenna portion 6 is provided. The top antenna unit 2 and the bottom antenna unit 3 may be connected to each other, and the top antenna unit 2, the bottom antenna unit 3, and the side antenna unit 6 may form the tag antenna AN ′ of the wireless tag T01. . Also in the wireless tag T01 of FIG. 4, the side antenna unit 6 can radiate radio waves in the same direction as the side antenna unit 4 in the example of FIG. 1 described above, so that radio waves can be transmitted in at least two directions (two axes). Can radiate.

  The RFID tag T01 shown in FIG. 4 has the same structure as that of the example of FIG. 1 except that a rod-like side antenna part 6 is provided instead of the configuration of the side antenna part 4 in the example of FIG.

-RFID system-
An RFID system as shown in FIG. 20 can be constructed using the wireless tag T0 shown in FIG. In this case, in the RFID system of FIG. 20, the RFID tag is captured by the tag antenna AN of the wireless tag T0 sent from the reader RW and supplied to the tag IC5. In the tag IC5, the input signal is reflected and modulated by the memory information in the IC, and the signal radiated again from the tag antenna AN to the reader RW side and radiated to the reader RW side is received by the reader antenna RA of the reader RW. Demodulated. As a result, the wireless tag T0 operates and information in the tag is extracted by the reader RW.

<Embodiment 2>
FIG. 5 is a plan view showing another example of the wireless tag of the present invention. 6 is a perspective view of the wireless tag of FIG. 5 as viewed from the upper surface side.

  The RFID tag T1 of this example includes a rectangular parallelepiped (or thin substrate) dielectric 11, and an upper surface antenna portion 12, a lower surface antenna portion 13 and a top surface antenna portion 12 formed on the upper surface 11a, the lower surface 11b, and the side surface 11c of the dielectric 11, respectively. A side antenna unit 14 and a tag IC 5 are provided.

  The top antenna unit 12 and the bottom antenna unit 13 are electrically connected by a side antenna unit 14, and the top antenna unit 12, the bottom antenna unit 13, and the side antenna unit 14 form one tag antenna AN1. . Further, the tag IC 5 is mounted on the upper surface antenna portion 12 and is electrically connected to the electrode terminal portion 12 a formed at the conductor end of the upper surface antenna portion 12.

  In the RFID tag T1 of this example, the tag antenna AN1 is configured by the upper surface antenna portion 12, the lower surface antenna portion 13, and the side surface antenna portion 14, and the tag antenna AN1 is formed into a three-dimensionally bent pattern. Portion 12, tag IC 5, side antenna portion 14, and lower surface antenna portion 13 is approximately λg / 2 of the equivalent electrical length (λg) of the communication frequency (λg is an equivalent wavelength including the dielectric constant effect of the dielectric) ) Is set. Therefore, the length of the wireless tag T1 is approximately λg / 4, which is about 1/2 of the size of a normal dipole antenna type wireless tag.

  Note that the length including the upper surface antenna portion 12, the tag IC 5, the side surface antenna portion 14, and the lower surface antenna portion 13 is approximately one wavelength or less (approximately one wavelength less than the equivalent electrical length of the communication frequency) in the same manner as a normal dipole antenna. May be included).

  Further, in the wireless tag T1 of this example, as shown in the plan view of FIG. 5, more radio waves are radiated in the lateral direction (the lateral direction of the paper) of the upper surface antenna portion 12 and the lower surface antenna portion 13. The projection area in which the upper surface antenna portion 12 on the upper surface 11a of the dielectric 11 is projected perpendicularly to the lower surface 11b of the dielectric 11 and the formation region of the lower surface antenna portion 13 on the lower surface 11b are shifted from each other; The side antenna part 14 that connects the upper surface antenna part 12 and the lower surface antenna part 13 is characterized in that it has a pattern that bends in a crank shape (or L shape).

Next, the operation of the wireless tag T1 of this example will be described with reference to FIG.
First, assuming that the radio wave signal transmitted from the reader RW (see FIG. 20) is received by the tag antenna AN1 of the wireless tag T1 of this example, reflected and modulated by the tag IC5, and transmitted from the tag IC5, the tag IC5. The signal wave from the resonance with the folded λg / 2 antenna excites the tag antenna AN1.

  The current I flowing through the tag antenna AN1 that is turned back by the excitation of the tag IC5 flows in the reverse direction between the upper surface antenna portion 12 and the lower surface antenna portion 13. As a result, signal waves having electric field components Eb and Eb ′ that are opposite to each other are radiated from the upper surface antenna portion 12 and the lower surface antenna portion 13, as indicated by the one-dot chain line in FIG. The radiated signals become their combined waves, but act so as to cancel each other because the direction of the electric field is opposite.

  By the way, the signal waves having the opposite electric fields Eb and Eb ′ are radiated in the horizontal direction in FIG. 5, respectively. In this example, the positional relationship between the upper surface antenna portion 12 and the lower surface antenna portion 13 is shifted. Therefore, the effect of shortening the wavelength of the dielectric 11 is also received, and a phase difference of λgw is generated at the equivalent electrical wavelength. Accordingly, the signal waves having opposite phases are combined with each other in a phase relationship accompanied by the propagation of λgw and radiated from the radio tag T1 in the horizontal direction of the paper surface. Therefore, the radiated radio waves from the upper surface antenna unit 12 and the lower surface antenna unit 13 Even if is the same, the composite wave will not disappear. Furthermore, when the phase difference due to λgw is π, the radiation signals from the top antenna unit 12 and the bottom antenna unit 13 are in phase with each other, and the electric field components are added to maximize the radiation effect.

  In this example, as shown in FIG. 6, the side antenna portion 14 is bent at a right angle, so that the side antenna portion 14 is subjected to a current flowing in the vertical direction (direction perpendicular to the paper surface of FIG. 5). Since the signal wave having the electric field component Ec is radiated, and further, the signal wave having the electric field component Ed is radiated by the current flowing in the lateral direction (the left-right direction in FIG. 5) through the side antenna portion 14, A radio wave can be radiated in three directions (three axes) together with the radiation direction of the signal wave radiated from the lower surface antenna unit 13.

  Here, in the example of FIG. 5, the side antenna portion 14 has a bent pattern. However, the side antenna portion is not limited to this, and may be any pattern that can connect the top antenna portion 12 and the bottom antenna portion 13. For example, as shown in FIG. 7, the side antenna 140 may be a belt-shaped pattern inclined obliquely downward from the conductor end of the upper surface antenna portion 12 toward the conductor end of the lower surface antenna portion 13.

  5 and FIG. 6 and the example of FIG. 7, the upper surface antenna portion 12 and the lower surface antenna portion 13 are connected by the side surface antenna portions 14 and 140, but these antenna portions 14 and 140 are replaced. Thus, the top antenna portion 12 and the bottom antenna portion 13 may be connected by a rod-shaped side antenna portion (see FIG. 4) penetrating the dielectric 11.

<Embodiment 3>
FIG. 8 is a plan view showing another example of the wireless tag of the present invention. FIG. 9 is a perspective view of the wireless tag of FIG. 8 as viewed obliquely from above.

  The RFID tag T2 of this example includes a rectangular parallelepiped (or thin substrate) dielectric 21, and an upper surface antenna portion 22, a lower surface antenna portion 23 formed on the upper surface 21a, the lower surface 21b, and the side surface 21c of the dielectric 21, respectively. A side antenna unit 24 and a tag IC 5 are provided.

  The top antenna unit 22 and the bottom antenna unit 23 are electrically connected by a side antenna unit 24, and the top antenna unit 22, the bottom antenna unit 23, and the side antenna unit 24 form one tag antenna AN2. . The tag IC 5 is mounted on the top antenna 22 and is electrically connected to the electrode terminal portion 22 a formed on the conductor end of the top antenna portion 22. The top antenna portion 22 and the bottom antenna portion 23 have different conductor widths / lengths.

  In the RFID tag T2 of this example, the tag antenna AN2 is composed of the upper surface antenna portion 22, the lower surface antenna portion 23, and the side surface antenna portion 24, and the tag antenna AN2 is a three-dimensionally bent pattern. The portion 22 has an L-shaped folding pattern. The length of the L-shaped pattern including the upper surface antenna portion 22, tag IC 5, side antenna portion 24 and lower surface antenna portion 23 is approximately λg / 2 of the equivalent electrical length (λg) of the communication frequency (λg is a dielectric) Equivalent wavelength including dielectric constant effect). Accordingly, the length of the wireless tag T2 is approximately λg / 4, which is about 1/2 of the size of a normal dipole antenna type wireless tag.

  In addition, the length including the upper surface antenna portion 22, the tag IC 5, the side surface antenna portion 24, and the lower surface antenna portion 23 is approximately one wavelength or less (approximately one wavelength less than the equivalent electrical length of the communication frequency) in the same manner as a normal dipole antenna. May be included).

Next, the operation of the wireless tag T2 of this example will be described with reference to FIG.
First, the length direction (up and down direction in FIG. 8) of the upper surface antenna portion 22 and the lower surface antenna portion 23 and the electric field component parallel to the side surface antenna portion 24 (front and rear direction in FIG. 8) are described with reference to FIGS. The radio waves are radiated in the same direction as those examples.

  That is, as shown by a one-dot chain line in FIG. 8, a signal wave that is parallel to the paper surface and becomes an electric field component Eb in the vertical direction of the paper surface is radiated in the horizontal direction and the front-back direction of the paper surface from the upper surface antenna portion 22 and the lower surface antenna portion 23. Further, a signal wave having a direction Ec perpendicular to the paper surface is radiated from the side antenna unit 24.

  On the other hand, a signal wave having a horizontal electric field Ed on the paper surface of FIG. 8 is generated from the top and bottom of the paper surface of FIG. Radiated in the direction of the upper and lower surfaces. Therefore, in the wireless tag T2 of this example, signals having electric field components in three directions (three axes) orthogonal to each other are radiated in all directions.

  In the example of FIG. 8 as well, a signal having a component in the same direction as the electric field Ed is radiated from the side antenna unit 24 by the same action as the side antenna unit 14 described in FIG.

  Here, in the example of FIG. 8, the upper surface antenna portion 22 and the lower surface antenna portion 23 are connected by the side surface antenna portion 24, but instead of the antenna portion 24, a rod-shaped side portion that penetrates the dielectric 21. It is good also as a structure which connects the upper surface antenna part 22 and the lower surface antenna part 23 with an antenna part (refer FIG. 4).

<Embodiment 4>
FIG. 10 is a perspective view of another example of the wireless tag of the present invention as viewed obliquely from above.

  The RFID tag T3 in this example includes a rectangular parallelepiped (or thin substrate) dielectric 31, and an upper surface antenna 32, a lower surface antenna 33, and a lower surface antenna 33 formed on the upper surface 31a, the lower surface 31b, and the side surface 31c of the dielectric 31, respectively. A side antenna portion 34 and a tag IC 5 are provided.

  The upper surface antenna portion 32 and the lower surface antenna portion 33 are electrically connected by a side antenna portion 34, and the upper surface antenna portion 32, the lower surface antenna portion 33, and the side surface antenna portion 34 form one tag antenna AN3. . The tag IC 5 is mounted on the top antenna 32 and is electrically connected to an electrode terminal portion 32 a formed at the conductor end of the top antenna portion 32. The top antenna portion 32 and the bottom antenna portion 33 have different conductor widths and lengths.

  In the RFID tag T3 of this example, the tag antenna AN3 is constituted by the upper surface antenna portion 32, the lower surface antenna portion 33, and the side surface antenna portion 34, and the tag antenna AN3 is formed into a three-dimensionally bent pattern. It is characterized in that the upper surface antenna portion 32 is shaped differently from the lower surface antenna portion 33 (a shape with a different projection shape) as a pattern in which the portion 32 is inclined in a slanting direction.

  Also in this example, the length including the upper surface antenna portion 32, the tag IC 5, the side antenna portion 34, and the lower surface antenna portion 33 is approximately λg / 2 of the equivalent electrical length (λg) of the communication frequency (λg is a dielectric material) Equivalent wavelength including the dielectric constant effect), and is downsized to about ½ compared to a normal dipole antenna type wireless tag.

  According to the wireless tag T3 of this example, as shown in FIG. 10, a signal wave having an electric field Ee is radiated by the current flowing through the upper surface antenna portion 32. This electric field component has a lateral electric field component Ed similar to that shown in the example of FIG. 8, as indicated by a dashed line in FIG. Further, the radiation in the other direction is caused by the same effect as the example of FIG. Therefore, also in the wireless tag T3 of this example, a signal having electric field components in three directions (three axes) is radiated from the tag antenna AN3 in all directions.

  In this example, the length including the upper surface antenna portion 32, the tag IC 5, the side surface antenna portion 34, and the lower surface antenna portion 33 is approximately one wavelength or less of the equivalent electrical length of the communication frequency, as in a normal dipole antenna ( It is preferable to include substantially one wavelength.

  In this example, the upper surface antenna portion 32 and the lower surface antenna portion 33 are connected by the side surface antenna portion 34, but instead of the antenna portion 34, a rod-shaped side antenna portion (through the dielectric 31) ( 4), the top antenna portion 32 and the bottom antenna portion 33 may be connected.

<Embodiment 5>
FIG. 11 is a longitudinal sectional view showing another example of the wireless tag of the present invention.

  The wireless tag T4 of this example is formed on a trapezoidal dielectric body 41 whose upper surface 41a is inclined with respect to the lower surface 41b, the upper surface 41a and the lower surface 41b of the dielectric material 41, and the two side surfaces 41c and 41d, respectively. An upper surface antenna portion 42, a lower surface antenna portion 43, two side antenna portions 44 and 46, and a tag IC 5 are provided.

  The top antenna section 42 and the bottom antenna section 43 are electrically connected by a side antenna section 44, and one tag antenna AN4 is formed by the top antenna section 42, the bottom antenna section 43, and the two side antenna sections 44 and 46. Is formed. The tag IC 5 is mounted on the side antenna 44 and is electrically connected to the electrode terminal portion 44 a formed at the conductor end of the side antenna portion 44.

  According to the RFID tag T4 of this example, the upper surface antenna portion 42 is inclined with respect to the lower surface antenna portion 43. Therefore, when a current I is generated in the tag antenna AN4, the electric field Ee parallel to the upper surface antenna portion 42 is obtained. Then, an electric field Ea ′ parallel to the lower antenna portion 43 is induced and radiated.

  Here, the electric field component Ee radiated by the upper surface antenna section 42 can be vector-decomposed into electric fields Ea and Ec ′ parallel to the electric field Ea ′, and thus the electric field component Ec in the side surface direction (see FIGS. 3 and 5). An electric field Ec ′ in the same direction is generated. Therefore, the radio tag T4 of this example can radiate radio waves in at least two directions (two axes).

  In this example, if at least one of the top antenna section 42, the bottom antenna section 43, and the side antenna section 44 is an L-shaped pattern that bends at right angles, the three directions (three axes) are different from each other. Thus, it has radio wave radiation characteristics, and communication by the reader is possible from three different directions.

  In this example, the upper surface antenna portion 42 and the lower surface antenna portion 43 are connected by the side surface antenna portion 44, but instead of the antenna portion 44, a rod-shaped side antenna portion (through the dielectric 41) ( 4), the top antenna portion 42 and the bottom antenna portion 43 may be connected.

<Embodiment 6>
FIG. 12 is a perspective view of another example of the wireless tag of the present invention viewed obliquely from above.

  The RFID tag T5 in this example includes a dielectric 51 having a structure in which an upper surface 51a is inclined in two directions with respect to a lower surface 51b, and an upper surface antenna portion 52 formed on the upper surface 51a, the lower surface 51b, and the side surface 51c of the dielectric 51, respectively. , The lower surface antenna portion 53 and the side surface antenna portion 54, and the tag IC 5.

  The top antenna unit 52 and the bottom antenna unit 53 are electrically connected by a side antenna unit 54, and the top antenna unit 52, the bottom antenna unit 53, and the side antenna unit 54 form one tag antenna AN5. . The tag IC 5 is mounted on the top antenna 52.

  According to the RFID tag T5 of this example, since the upper surface antenna portion 52 is arranged in two directions with respect to the lower surface antenna portion 53, the radio wave radiation axes or radiation surfaces of the upper surface and the lower surface have different directions. For directing, the directivity characteristics of the tag antenna AN5 are directed in different directions.

  In this example, if at least one antenna part of the top antenna part 52, the bottom antenna part 53, and the side antenna part 54 is an L-shaped pattern that bends at right angles, the three directions (three axes) are different from each other. Thus, it has radio wave radiation characteristics, and communication by the reader is possible from three different directions.

  In this example, the upper surface antenna portion 52 and the lower surface antenna portion 53 are connected by the side surface antenna portion 54, but instead of the antenna portion 54, a rod-shaped side antenna portion (through the dielectric 51) ( 4), the top antenna portion 52 and the bottom antenna portion 53 may be connected.

  Further, in this example, each antenna unit 52 is arranged such that the projection area obtained by projecting the upper surface antenna part 52 of the upper surface 51a of the dielectric 51 perpendicularly to the lower surface 51b and the formation area of the lower surface antenna part 53 of the lower surface 51 are shifted from each other. 53, or the projected shape obtained by projecting the upper surface antenna portion 52 of the upper surface 51a of the dielectric 51 perpendicularly to the lower surface 51b may be different from the shape of the lower surface antenna portion 53 of the lower surface 51b. .

<Embodiment 7>
FIG. 13 is a longitudinal sectional view showing the configuration of another example of the wireless tag of the present invention.

  The wireless tag T6 in this example is formed on each of the dielectric 61 having a right-angled triangle (wedge shape) having two surfaces 61a and 61b adjacent to each other at an acute angle, and the two surfaces 61a and 61b, respectively. Two antenna portions 62 and 63 that are electrically connected to each other and a tag IC 5 are provided, and the two antenna portions 62 and 63 form one tag antenna AN6. In addition, the IC tag 5 is mounted on one antenna part 62 of the antenna parts 62 and 63 formed on the two surfaces 61 a and 61 b of the dielectric 61.

  According to the wireless tag T6 of this example, the side antenna portion is apparently not provided, but one antenna portion 62 (upper surface side) is arranged to be inclined with respect to the other antenna portion 63 (lower surface side). Therefore, an electric field component similar to that in the above-described example of FIG. 11 is generated from an electric field component obliquely radiated from one of the inclined antenna portions 62, and the directivity characteristics of the tag antenna AN6 are directed in different directions.

  Here, in the example of FIG. 13, a projection area obtained by projecting the antenna portion 62 of one surface 61a of the two surfaces 61a and 61b of the dielectric 61 perpendicularly to the other surface 61b and the antenna portion of the other surface 61b. The antenna portions 62 and 63 are arranged so as to be offset from each other, or the antenna portion 62 of one surface 61a of the two surfaces 61a and 61b of the dielectric 61 is placed on the other surface 61b. You may make it the shape from which the projection shape projected perpendicularly differs from the shape of the antenna part 63 of the other surface 61b.

  In the example of FIG. 13, at least one antenna part of the two antenna parts 62 and 63 may be an L-shaped pattern that is bent at a right angle.

  In the example of FIG. 13, the two surfaces of the dielectric 61 are both flat, but as shown in FIG. 14, one surface 161a of the two surfaces 161a and 161b of the dielectric 161 is a curved surface (circular curved surface). One antenna portion 162 may have a curved pattern. In this case, since a current flows along the antenna portion 162 having a curved pattern, an electric field component induced by the current flows in multiple directions.

  Here, in each example of FIG. 12 and FIG. 13, the angle formed by the two surfaces of the dielectric is an acute angle. However, the present invention is not limited to this, and the present invention can be implemented even when the angle formed by the two surfaces of the dielectric is an obtuse angle. Is possible.

<Eighth embodiment>
FIG. 15 is a longitudinal sectional view showing another example of the wireless tag of the present invention. FIG. 16 is a perspective view of the wireless tag of FIG. 15 as viewed from above.

  The RFID tag T7 in this example includes a rectangular parallelepiped (or thin substrate) dielectric 71, and an upper surface antenna portion 72, a lower surface antenna portion 73, and a lower surface antenna portion 73 formed on the upper surface 71a, the lower surface 71b, and the side surface 71c of the dielectric 71, respectively. A side antenna unit 74 and a tag IC 5 are provided.

  The upper surface antenna portion 72 and the lower surface antenna portion 73 are electrically connected by a side antenna portion 74, and the upper surface antenna portion 72, the lower surface antenna portion 73, and the side surface antenna portion 74 form one tag antenna AN7. . The tag IC 5 is mounted on the side antenna 74 and is electrically connected to the electrode terminal portion 74 a formed at the conductor end of the side antenna portion 74. Further, as shown in the perspective view of FIG. 16, the lower surface antenna portion 73 is formed on the entire lower surface of the dielectric 71, and the length of the upper surface antenna portion 72 formed on a part of the upper surface 71 a of the dielectric 71 is longer. And the width is different.

  In the wireless tag T7 of this example, the tag antenna AN7 is configured by the upper surface antenna portion 72, the lower surface antenna portion 73, and the side surface antenna portion 74, and the tag antenna AN7 is formed in a three-dimensionally bent pattern. Further, the length of the side antenna portion 74 including the upper surface antenna portion 72 and the tag IC 5 is set to approximately λg / 4 of the equivalent electrical length (λg) of the communication frequency, and the length of the lower surface antenna portion 73 is communicated. It is set to approximately λg / 4 of the equivalent electrical length (λg) of the frequency. Accordingly, the length of the wireless tag T7 is approximately λg / 4, which is about 1/2 of the size of a normal dipole antenna type wireless tag.

  The length of the side antenna portion 74 including the upper surface antenna portion 72 and the tag IC 5 and the length of the lower surface antenna portion 73 are approximately ½ wavelength or less (including approximately ½ wavelength) of the equivalent electrical length of the communication frequency. ) Is preferable.

Next, the operation of the wireless tag T7 in this example will be described with reference to FIGS.
First, when the wireless tag T7 of this example is present alone (state shown in FIG. 15), the wireless tag operates as a wireless tag having the operation and radiation characteristics described in FIG. 3, and thus detailed description thereof is omitted here.

  On the other hand, assuming that the RFID tag T7 of this example is attached to the metal body 100 having an area larger than the radiating portion of the tag antenna AN7, as shown in FIG. In contact with the metal body surface 101 at a high frequency.

  At this time, since the electric field component parallel to the surface cannot exist on the metal surface 101, the image antenna 102 accompanied by the radiation in which the electric field component radiated from the upper surface antenna 72 is canceled by the metal surface 101 is formed on the metal surface 101. It is equivalent to the one installed on the opposite side of the actual antenna via

  This image antenna 102 is an antenna that is provided symmetrically with the antenna that actually exists with respect to the metal surface (ground plane) 101, and a current in the direction opposite to that of the upper surface antenna portion 72 flows, and an electric field induced thereby. Are radiated in the horizontal direction of FIG. Therefore, the radio wave signal radiated to the outside from the top antenna unit 72 can be regarded as a combination of radiation from the top antenna unit 72 and radiation from the image antenna 102. In the figure, the alternate long and short dashed lines indicate the directions of the electric field components radiated from the upper surface antenna portion 72 and the image antenna 102, respectively.

  Here, the electric field directions of the actual antenna and the image antenna are opposite to each other and cancel each other. However, in FIG. The phase rotation occurs as the distance between the two, that is, the distance corresponding to the electrical length Hg, advances, and the combined wave generates an effective signal intensity due to the phase difference. And since the dielectric constant of the dielectric 71 shortens the signal propagation wavelength in the dielectric, it can give a larger phase rotation and contribute to effective radio wave radiation. In particular, when the electrical length Hg / 2 is λg / 4 of the equivalent electrical wavelength (λg) of the signal, the above-described combined wave is in phase and the strongest radio wave emission is generated upward. The current flowing through the side antenna unit 74 has no reverse component, and the electric field induced by the current flowing through the side antenna unit 74 is radiated in parallel with the side surface.

  As described above, the wireless tag T7 of this example performs a tag operation based on the original operation principle with a single tag, and has the great advantage that it can be used for a metal object when it is attached to a metal body.

  In this example, the tag IC 5 is mounted on the side antenna portion 74, but the tag IC 5 may be mounted on the upper surface antenna portion 72 without being limited thereto.

  Also, in this example, if the top antenna portion 72 (or the side antenna portion 74) is an L-shaped pattern that is bent at a right angle, it has radio wave radiation characteristics in three different directions (three axes). Communication by the reader is possible from three different directions.

  Furthermore, in this example, each antenna part 72, 73 is formed such that the projection area obtained by projecting the upper surface antenna part 72 of the upper surface 71a of the dielectric 71 onto the lower surface 51b and the formation area of the lower surface antenna part 73 of the lower surface 71b are shifted from each other. Alternatively, the projected shape obtained by projecting the upper surface antenna portion 72 of the upper surface 71a of the dielectric 71 perpendicularly to the lower surface 71b and the shape of the lower surface antenna portion 73 of the lower surface 71b may be different.

  Here, the same can be said for the wireless tag T6 in FIG. 13 with respect to the operation and the like when the wireless tag is attached to a metal body.

<Ninth Embodiment>
18 and 19 are perspective views showing other examples of the wireless tag of the present invention.

  18 includes a tag antenna AN8 formed of a rectangular parallelepiped (or thin substrate) dielectric 81, a top antenna 82, a bottom antenna 83, and a side antenna 84, and a tag IC5. Further, the impedance matching circuit 86 is provided by forming a reactance component by partially reducing the conductor width of the upper surface antenna portion 82. Thus, by forming the inductance component with the thin conductor in the upper surface antenna portion 82, the strong capacitive component of the tag IC can be canceled. Note that a lumped reactance component may be used instead of the reactance matching circuit 86 as shown in FIG.

  A radio tag T9 shown in FIG. 19 includes a tag antenna AN9 including a top antenna portion 92, a bottom antenna portion 93, and a side antenna portion 94 formed on a rectangular parallelepiped (or thin substrate) dielectric 91, and a tag IC5. The upper surface antenna portion 92 and the lower surface antenna portion 93 are characterized by providing cuts (slits) 92 s and 93 s along a direction orthogonal to the current flowing through the antenna portions 92 and 93. By providing such cuts 92s and 93s, the current path is lengthened and a reactance component is generated. Therefore, the lengths of the upper surface antenna portion 92 and the lower surface antenna portion 93 can be shortened accordingly, and the entire tag Can be miniaturized. Instead of the cuts 92 s and 93 s, the antenna length may be shortened by providing convex portions on the peripheral portions of the upper surface antenna portion 92 and the lower surface antenna portion 93.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used when constructing an RFID system having high communication reliability and operability and a wide range of use in various fields such as FA, logistics, distribution, and merchandise history management.

It is a figure which writes together and shows the top view (A) and center longitudinal cross-sectional view (B) which show an example of the radio | wireless tag of this invention. FIG. 2 is a diagram illustrating a perspective view (A) of the wireless tag in FIG. 1 as viewed from the upper surface side and a perspective view (B) as viewed from the lower surface side. It is operation | movement explanatory drawing of the radio | wireless tag of FIG. It is the figure which writes together and shows the perspective view (A) which looked at the other example of the wireless tag of this invention from the upper surface side, and the perspective view (B) seen from the lower surface side. It is a top view which shows another example of the radio | wireless tag of this invention. It is the perspective view which looked at the radio | wireless tag of FIG. 5 from the upper surface side. It is the perspective view which looked at another example of the radio | wireless tag of this invention from diagonally upward. It is a top view which shows another example of the radio | wireless tag of this invention. It is the perspective view seen from diagonally upward of the wireless tag of FIG. It is the perspective view which looked at another example of the radio | wireless tag of this invention from diagonally upward. It is a longitudinal cross-sectional view which shows another example of the radio | wireless tag of this invention. It is the perspective view which looked at another example of the radio | wireless tag of this invention from diagonally upward. It is a longitudinal cross-sectional view which shows another example of the radio | wireless tag of this invention. It is a longitudinal cross-sectional view which shows another example of the radio | wireless tag of this invention. It is a longitudinal cross-sectional view which shows another example of the radio | wireless tag of this invention. FIG. 16 is a perspective view of the wireless tag of FIG. 15 viewed from obliquely above. FIG. 16 is an operation explanatory diagram when the wireless tag of FIG. 15 is attached to a metal body. It is the perspective view which looked at another example of the radio | wireless tag of this invention from diagonally upward. It is the top view which looked at another example of the radio | wireless tag of this invention from diagonally upward. 1 is a diagram illustrating a basic configuration of an RFID system. It is a top view which shows an example of the conventional radio | wireless tag.

Explanation of symbols

T0 wireless tag AN tag antenna 1 dielectric 1a upper surface 1b lower surface 1c side surface 2 upper surface antenna portion 2A electrode terminal 3 lower surface antenna portion 4 side antenna portion (side antenna portion)
5 Tag IC
6 Rod-shaped side antenna portion T1 Wireless tag AN1 Tag antenna 11 Dielectric 12 Upper surface antenna portion 13 Lower surface antenna portion 14 Side antenna portion (Crank-shaped or L-shaped pattern)
T2 wireless tag AN2 tag antenna 21 dielectric 22 upper surface antenna (L-shaped pattern)
23 Lower surface antenna portion 24 Side antenna portion T3 Wireless tag AN3 Tag antenna 31 Dielectric 32 Upper surface antenna portion (inclined band pattern)
33 Bottom antenna part 34 Side antenna part T4 Wireless tag AN4 Tag antenna 41 Dielectric (trapezoidal cross section)
42 Upper surface antenna portion 43 Lower surface antenna portion 44 Side antenna portion T5 Wireless tag AN5 Tag antenna 51 Dielectric 52 Upper surface antenna portion 53 Lower surface antenna portion 54 Side antenna portion T6 Wireless tag AN6 Tag antenna 61 Dielectric (cross-sectional right triangle)
61a, 61b Two surfaces 62, 63 Antenna portion T7 Wireless tag AN7 Tag antenna 71 Dielectric 72 Upper surface antenna portion 73 Lower surface antenna portion 74 Side antenna portion 86 Matching circuit 92s, 93s Notch RW reader RA reader antenna

Claims (2)

A dielectric having upper and lower surfaces and side surfaces parallel or non-parallel to each other, an upper surface antenna portion, a lower surface antenna portion and a side antenna portion formed on the dielectric, and a tag IC, and at least the upper surface antenna 1 tag antenna is formed by the portion, the bottom antenna portion, and the side antenna portion, and the middle portion of any one of the plurality of antenna portions forming the tag antenna is cut and formed 2 A wireless tag , wherein the tag IC is connected and mounted between electrode terminal portions . The conductor length of the remaining antenna portion excluding the bottom antenna portion from the plurality of antenna portions forming the tag antenna is approximately ¼ wavelength of the equivalent electrical length of the communication frequency including the tag IC. The wireless tag according to claim 1, wherein:

Images