RFID cover with wave guide function and RFID tag set

Abstract

To provide a cover for a RFID with a thin type waveguide function, capable of enhancing an antishock property of an RFID tag, and provide a RFID tag set.SOLUTION: A cover 1 for a RFID with a waveguide function of the present invention, comprises: a main body part 2 that covers a front surface of a waveguide element 20 of a plate-like antenna; and a hanging part 3 that is hanged from a side of the main body part. At least the front surface and a side surface of an RFID tag 100 are covered with a coating layer 11 made of an insulation material, the main body part covers the front surface of the waveguide element via a coating film layer, and the hanging part covers the side surface of the waveguide element via the coated film layer. A coupling capacitor 4 containing an air layer is formed by the main body part, the hanging part, the coated film layer, and the waveguide element. By performing an electrostatic capacitance coupling of the coupling capacitor containing the air layer and a capacitor 93 of the plate-like antenna, an inductance of the RFID tag and a resonance circuit are formed. By adjusting a notch provided to the cover for the RFID, and changing permeability (μ) of a coil of the RFID tag, a resonance frequency can be adjusted to a preferable value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a thin RFID cover with a waveguide function and an RFID tag set that can improve the impact resistance of an RFID tag. [Background technology]

[0002] The RFID tags used in RFID (Radio Frequency Identification) systems contain an antenna and an RF chip, which receives the carrier waves transmitted from the antenna of the reader / writer and transmits the identification data recorded on the RF chip on reflected waves back to the reader / writer, thus enabling contactless communication. Depending on the application, RFID tags may be required to be shock resistant. For example, Patent Document 1 discloses a wireless IC tag that stores a first antenna and a second antenna inside a case, in which the second antenna resonates with the radio waves emitted from the first antenna, and radiates the amplified radio waves to the outside. Patent Document 2 discloses a spherical ID tag package in which the periphery of the ID tag is covered with an elastic body or a heat-resistant material. Patent Document 3 discloses an RF tag stored in a non-conductive case made of plastic or the like (see FIG. 6 of Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4778264 [Patent Document 2] Patent No. 4884383 [Patent Document 3] Patent No. 6705116 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, the RFID tag has a structure in which the RF chip and antenna are covered with a case or an elastic body, etc., which causes problems such as an increase in size and an increase in manufacturing costs. Furthermore, depending on the location where the RFID tag is installed, communication may become difficult due to communication directivity caused by phase and impedance matching.

[0005] In consideration of such problems, the present invention has an object to provide a thin RFID cover with a waveguide function and an RFID tag set that can increase the impact resistance of an RFID tag. [Means for solving the problem]

[0006] The RFID cover with wave guide function of the present invention is a conductive material used for an RFID tag having a plate-shaped antenna that receives radio waves transmitted from a reader and an IC chip that operates based on the radio waves. For RFID with waveguiding function The cover includes a main body portion covering a surface of the waveguide element of the plate-like antenna, and a hanging portion hanging down from a side of the main body portion, and at least the surface and side of the RFID tag are made of an insulating material. coating layer the main body covers a surface of the director element via the coating layer, and the hanging portion covers a side surface of the director element via the coating layer, and a coupling capacitor including an air layer is formed by the main body, the hanging portion, the coating layer, and the director element. The coupling capacitor is capacitively coupled to the capacitor of the RFID tag to form a resonant circuit with the inductor pattern of the RFID tag, thereby functioning as a part of the plate-like antenna. It is characterized by: The hanging portion may also be provided with a notch. The plate antenna is also characterized in that it is a plate inverted-F antenna. the first insulating substrate, the first waveguide element, the second waveguide element, the second waveguide element, the feeding portion, and the short-circuiting portion, the first end of which is electrically connected to the first waveguide element and the second end of which is electrically connected to the second waveguide element; the first insulating substrate, the first waveguide element, the second waveguide element, the feeding portion, and the short-circuiting portion receive the radio waves; an inductor pattern formed by the first waveguide element, the short-circuiting portion, the second waveguide element, and the feeding portion, and a capacitor formed by the first waveguide element, the second waveguide element, and the first insulating substrate form a resonant circuit that resonates in the frequency band of the radio waves; the main body and the hanging portion cover the first waveguide element via the coating layer; and the capacitor is capacitively coupled to a coupling capacitor including the air layer. The main body and the hanging portion are coating layer The second principal surface is provided with a gap between a lower end of the hanging portion and the second principal surface when viewed from the side with the first waveguide element covered therethrough. The first insulating base material is made of an elastic material. The RFID tag set of the present invention is an RFID tag set including an RFID tag having a planar antenna for receiving radio waves transmitted from a reader and an IC chip that operates based on the radio waves, and an RFID cover with wave guiding function according to claim 1 that is used for the RFID tag, wherein the planar antenna is a planar inverted-F antenna, and the planar inverted-F antenna includes a first insulating substrate having a first main surface and a second main surface opposite to the first main surface, a first waveguide element provided on the first main surface, a second waveguide element provided on the second main surface, a power supply unit having one end electrically connected to the second waveguide element, and a power supply unit having one end electrically connected to the first waveguide element and a second waveguide element provided on the second main surface. and a short-circuiting portion having the other end electrically connected to the waveguide element, and the radio waves are received by the first insulating substrate, the first waveguide element, the second waveguide element, the power supply portion and the short-circuiting portion, wherein an inductor pattern formed by the first waveguide element, the short-circuiting portion, the second waveguide element and the power supply portion, and a capacitor formed by the first waveguide element, the second waveguide element and the first insulating substrate form a resonant circuit which resonates in the frequency band of the radio waves, and wherein the main body and the hanging portion cover the first waveguide element via the coating layer, and the capacitor is capacitively coupled to a coupling capacitor including the air layer. Effect of the Invention

[0007] In the present invention, a coupling capacitor including an air layer is formed by the main body, the hanging portion, the coating layer and the waveguide element, and this coupling capacitor is capacitively coupled to the capacitor of the plate antenna to form a resonant circuit with the inductance of the RFID tag. By attaching an RFID cover to an RFID tag, the RFID cover functions as a waveguide element, but the inductance is reduced, and the resonant frequency is accordingly increased. In addition, the RFID cover is structured to cover the surface and side of the first waveguide element via a coating layer, and the perimeter of the RFID cover is always longer than that of the first waveguide element, which also has the effect of increasing the resonant frequency. Therefore, the resonant frequency can be adjusted to a desired value by providing a notch in the RFID cover near the inductance L portion of the RFID tag and adjusting the mu of the coil. In other words, as the RFID cover approaches the RFID tag, the inductance decreases and the resonant frequency increases; therefore, by providing a notch in the RFID cover and setting the mu when the RFID cover approaches, the frequency can be adjusted.

[0008] Since an RFID cover is attached to the RFID tag, a thinner RFID tag set can be obtained compared to the conventional case in which the RFID tag is stored inside a case. By providing the gap, even if the RFID tag is attached to a conductor such as a metal plate, it is possible to prevent the RFID cover from coming into contact with the metal plate or the like and causing a short circuit. Furthermore, if an elastic material such as polystyrene foam is used as the first insulating base material, when an external force is applied to the RFID cover, the polystyrene foam etc. can elastically deform by utilizing the gaps, thereby preventing the RFID tag from being damaged by external forces and increasing the impact resistance of the RFID tag. [Brief description of the drawings]

[0009] [Figure 1] (a) is a perspective view of an RFID tag, (b) is a perspective view of an RFID tag set with an RFID cover attached, and (c) is a front view. [Diagram 2] Front view (a), side view (b), plan view (c), bottom view (d) and AA cross-sectional view (e) of the RFID cover [Diagram 3](a) is a perspective view of the RFID tag seen from the top side, (b) is a perspective view of the RFID tag seen from the bottom side, and (c) is a development view of the sheet. [Figure 4] Equivalent circuit diagram of an RFID tag [Diagram 5] Equivalent circuit diagram of an RFID tag set with an RFID cover attached [Figure 6] Side view of RFID cover with cutout DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an RFID cover with a waveguiding function (hereinafter, may be simply referred to as an "RFID cover") of the present invention will be described with reference to the drawings. 1 and 2, an RFID cover 1 is a cover used for an RFID tag 100. By attaching the RFID cover 1 to the RFID tag 100, an RFID tag set 200 is formed. In this embodiment, the entire RFID tag 100, i.e., the front, back, front, left and right sides, are covered with a coating layer 11 made of an insulating material. coating layer The RFID tag is mounted on the surface of the base 12.

[0011] The RFID cover 1 is made of a conductor such as stainless steel, aluminum, iron, copper, or an alloy of these. The RFID cover 1 can increase the impact resistance of the RFID tag 100 when some external force acts on the RFID tag 100, such as when the RFID tag 100 is dropped or hit by an object, and also functions as an antenna for the RFID tag 100.

[0012] The RFID cover 1 comprises a main body portion 2 and a hanging portion 3 . The main body 2 is a member that covers, via a coating layer 11, the surface of a director element (a first director element 20 described below) of the plate antenna. Hanging portion 3 is a member that hangs down from the side of main body 2, and covers the side surface of the waveguide element (first waveguide element 20) with coating layer 11 interposed therebetween. That is, as shown in FIG. 2(e), the RFID cover 1 is in the shape of a box that opens downward, and is designed to store the upper part of the RFID tag 100 inside. Although a detailed explanation will be given later, the main body portion 2, the hanging portion 3, the coating layer 11 and the waveguide element (first waveguide element 20) form a coupling capacitor 4 (sometimes referred to simply as “coupling capacitor 4” in this specification) including an air layer.

[0013] 3(a) to 3(c), the RFID tag 100 includes a plate-like antenna 10 that receives radio waves transmitted from a reader, and an IC chip 80 that operates based on the radio waves, and in this embodiment, the entire tag is covered with a coating layer 11 made of an insulating material. Furthermore, an adhesive layer (not shown) may be provided on the bottom surface of the RFID tag 100, and the RFID tag 100 may be attached to an object via the adhesive layer. In this embodiment, a planar inverted-F antenna 10 will be used as an example of a planar antenna. The planar inverted-F antenna 10 includes a first director element 20, a second director element 30, a first insulating substrate 40, a power feeding portion 50, and a short-circuit portion 60. The first insulating base material 40 has an upper surface (first main surface) and a lower surface (second main surface) opposite to the first main surface. The first insulating base material 40 is, for example, a substantially rectangular parallelepiped, but is not limited to this. For example, it may be disk-shaped, or may have a cross section along the vertical direction curved into an arc.

[0014] The first director element 20 is provided on the upper surface of the first insulating substrate 40. The second director element 30 is provided on the lower surface of the first insulating substrate 40. The first director element 20 and the second director element 30 are both rectangular in shape and are formed by etching or pattern printing of a thin metal film such as aluminum. The first director element 20 and the second director element 30 have the same shape. In this application, the term "same shape" is not limited to the strict meaning of "same shape", but also includes a slight difference caused by the structure of the antenna. For example, when an IC chip 80 described later is provided on the same plane as the first director element 20, it is necessary to provide a recess 21 in a part of the first director element 20, which is, for example, rectangular, in order to place the IC chip 80, as shown in FIG. 3(a). In this case, the shapes of the first director element 20 and the second director element 30 are not strictly the same. However, since the first director element 20 has the same rectangular shape as the second director element 30, the first director element 20 and the second director element 30 are considered to have the same shape.

[0015] The power supply unit 50 is provided on a side surface of the short side of the first insulating substrate 40, and one end is electrically connected to the second waveguide element 30. The short-circuiting unit 60 is provided on a side surface of the short side of the first insulating substrate 40, and one end is electrically connected to the first waveguide element 20 and the other end is electrically connected to the second waveguide element 30. As shown in FIG. 3( c ), the power supply unit 50 and the short-circuiting unit 60 are members provided in parallel to each other on a sheet 70 so as to bridge between the first waveguide element 20 and the second waveguide element 30. The power feeding portion 50 and the short-circuit portion 60 may be provided on a side surface on the long side of the first insulating substrate 40. The power feeding portion 50 and the short-circuit portion 60 do not have to be provided parallel to each other. The power feeding portion 50 and the short-circuit portion 60 may be molded integrally with the first waveguide element 20 and the second waveguide element 30 at the same time. Alternatively, the power feeding portion 50 and the short-circuit portion 60 may be molded separately from the first waveguide element 20 and the second waveguide element 30, and then the respective ends of the power feeding portion 50 and the short-circuit portion 60 may be joined to the first waveguide element 20 and the second waveguide element 30.

[0016] The first director element 20, the second director element 30, the power supply portion 50 and the short-circuit portion 60 are formed on an insulating sheet 70, and are attached to the first insulating base material 40 via the sheet 70 which is folded at an edge portion of the first insulating base material 40. As will be described in detail later, the planar inverted-F antenna 10 can be easily manufactured by bending a flexible sheet 70 having the first director element 20, the second director element 30, the power supply portion 50 and the short-circuit portion 60 formed on one side thereof together with the power supply portion 50 and the short-circuit portion 60 and attaching the sheet to the first insulating base material 40.

[0017] The sheet 70 may be made of a flexible insulating material such as PET, polyimide, or vinyl. The thickness of the sheet 70 is not particularly limited, but is generally about several tens of μm. Furthermore, the surfaces of the first waveguide element 20 and the second waveguide element 30 may be coated with an insulating film. In this embodiment, the first waveguide element 20 and the second waveguide element 30 are formed on a sheet 70 (substrate), but they do not necessarily have to be formed on the sheet 70. For example, the first waveguide element 20 and the second waveguide element 30 may be formed separately. Alternatively, the first waveguide element 20 and the second waveguide element 30 may be formed on the sheet 70, and then the sheet 70 may be peeled off.

[0018] The first insulating substrate 40, the first waveguide element 20, the second waveguide element 30, the power supply 50, and the short circuit 60 constitute the planar inverted-F antenna 10. This planar inverted-F antenna 10 receives radio waves transmitted from a reader (not shown). When the first waveguide element 20 absorbs radio waves, the second waveguide element 30 acts as a conductive ground plate. On the other hand, when the second waveguide element 30 absorbs radio waves, the first waveguide element 20 acts as a conductive ground plate. In other words, the first waveguide element 20 and the second waveguide element 30 can function as both a waveguide element and a conductive ground plate depending on the usage mode of the RFID tag 100.

[0019] The first waveguide element 20 is designed so that the total length A of its sides 20a-20f is any one of λ / 4, λ / 2, 3λ / 4, and 5λ / 8. Here, λ is the wavelength of the radio wave transmitted from the reader. The wavelength λ of the radio wave is not particularly limited as long as it is within a range usable for the RFID tag 100. The second waveguide element 30 is designed so that the total length B of its sides 30a-30d is approximately equal to the total length A.

[0020] As described above, the first waveguide element 20 and the second waveguide element 30 have the same shape, and the sums A and B of the lengths of the sides of the first waveguide element 20 and the second waveguide element 30 are approximately equal to any one of λ / 4, λ / 2, 3λ / 4, and 5λ / 8. This makes it possible to easily set the resonance frequency of the planar inverted-F antenna 10. Furthermore, the RFID tag 100 can be operated independently without being affected by the installation location (for example, without the first waveguide element 20 and the second waveguide element 30 being in contact with a conductor). As long as the total side lengths A and B of the first and second waveguide elements 20 and 30 are any of the above values, the planar shapes of the first and second waveguide elements 20 and 30 are not limited to a rectangular shape; for example, the first and second waveguide elements 20 and 30 may be square-shaped with their centers cut out.

[0021] An insulator may be used as the first insulating base material 40. This makes it possible to secure a certain degree of opening area and improve the sensitivity of the plate-shaped inverted F antenna 10. For example, polystyrene foam can be used as the first insulating base material 40. The first insulating substrate 40 may be a dielectric. For example, a dielectric having a relative dielectric constant of 1 or more and 20 or less may be used as the first insulating substrate 40. When a dielectric having a large dielectric constant (for example, ceramic) is used, the capacitance of the capacitor 93 increases, so that the opening areas of the first director element 20 and the second director element 30 become smaller, and the RFID tag 100 can be made smaller. However, the gain of the planar inverted-F antenna 10 decreases, so that the distance over which communication can be made with the reader (communication distance) becomes shorter. When a relatively long communication distance, such as several meters or more, is required, a dielectric having a small dielectric constant is used as the first insulating substrate 40. In this case, the relative dielectric constant is preferably 5 or less.

[0022] As shown in Fig. 4, the planar inverted F antenna 10 forms a resonant circuit that resonates in the frequency band of the radio waves transmitted from the reader. This resonant circuit is composed of an inductor pattern L and a capacitor 93. Here, the inductor pattern L is composed of the first director element 20, the short circuit portion 60, the second director element 30, and the power supply portion 50, and the capacitor 93 is composed of the first director element 20, the second director element 30, and the first insulating substrate 40. This resonant circuit enables the planar inverted F antenna 10 to receive the radio waves transmitted from the reader with high sensitivity, thereby improving the reading performance of the RFID tag 100. Furthermore, the power supply voltage generated by the IC chip 80 can be increased.

[0023] 3(a), the IC chip 80 is provided between the first director element 20 and the power supply unit 50. The IC chip 80 is disposed on the upper surface side of the first insulating base material 40 (on the same plane as the first director element 20). The IC chip 80 may be disposed on the side surface of the first insulating base material 40 as long as it is within a range where it functions as the planar inverted-F antenna 10. Also, an external power supply may be connected to the IC chip 80 so that the IC chip 80 operates by the voltage supplied from the external power supply.

[0024] The IC chip 80 operates based on radio waves from the reader received by the plate-shaped inverted-F antenna 10. Specifically, the IC chip 80 first rectifies a part of the carrier waves transmitted from the reader to generate a power supply voltage necessary for the IC chip 80 itself to operate. Then, the IC chip 80 operates a control logic circuit within the IC chip 80 using the generated power supply voltage. The IC chip 80 also operates a communication circuit and the like for transmitting and receiving data to and from the reader.

[0025] Some IC chips 80 include a capacitor therein, and the IC chips 80 have stray capacitance. For this reason, it is preferable to take into consideration the equivalent capacitance inside the IC chip 80 when setting the resonant frequency of the resonant circuit. In other words, it is preferable for the resonant circuit to have a resonant frequency that is set in consideration of the inductance of the inductor pattern L, the capacitance of the capacitor 93, and the equivalent capacitance inside the IC chip 80. Furthermore, it is necessary to take into consideration the capacitance of the coupling capacitor 4, as will be described later.

[0026] The resonant frequency f [Hz] of the resonant circuit is given by the following formula (1): The value of the resonant frequency f is set so as to be included in the frequency band of the radio waves transmitted from the reader.

[0027]

number

[0028] In the formula (1), La represents the inductance of the inductor pattern L, Ca represents the capacitance of the capacitor 93, and Cb represents the equivalent capacitance inside the IC chip 80.

[0029] As described above, some IC chips 80 include a capacitor therein, and the IC chips 80 have stray capacitance. Therefore, when setting the resonant frequency f of the resonant circuit, it is preferable to take into consideration the equivalent capacitance Cb inside the IC chip 80. That is, it is preferable that the resonant circuit has a resonant frequency f that is set in consideration of the inductance of the inductor pattern L, the capacitance of the capacitor 93, and the equivalent capacitance Cb inside the IC chip 80. Note that, for example, a capacitance value published as one of the specification parameters of the IC chip 80 to be used can be used as Cb.

[0030] By taking into consideration the equivalent capacitance Cb inside the IC chip 80, the resonant frequency f of the resonant circuit can be set accurately to the frequency band of the radio wave. As a result, the reading performance of the RFID tag 100 can be further improved. In addition, the power supply voltage generated by the IC chip 80 can be further increased.

[0031] FIG. 5 is a diagram showing an example of an equivalent circuit of the RFID tag 100 with the RFID cover 1 attached. As described above, the coupling capacitor 4 is formed by the main body 2 and hanging portion 3 of the RFID cover 1, the coating layer 11 (insulating material), and the first waveguide element 20 of the RFID tag 100, and forms a resonant circuit with the inductance of the RFID tag 100 by capacitively coupling with the capacitor 93. The formation of the coupling capacitor 4 gives the RFID cover 1 a waveguide function, making it possible to guide the radio waves transmitted and received from the first waveguide element 20 and communicate with a reader.

[0032] The coupling capacitor 4 is connected in series with a capacitor 93 that is configured by the first director element 20, the second director element 30, and the insulating substrate 140. Therefore, the combined capacitance of the capacitor 93 and the coupling capacitor 4 changes, and the resonant frequency of the resonant circuit of the RFID tag 100 may change. By attaching the RFID cover 1 to the RFID tag 100, the RFID cover 1 functions as a waveguide element, but the attachment raises the resonant frequency. The RFID cover 1 is structured to cover the front and side surfaces of the first waveguide element 20 via the coating layer 11, which also has the effect of raising the resonant frequency. Therefore, the resonant frequency can be adjusted to a preferred value by adjusting the mu of the coil L of the RFID tag 100. When adjusting the mu of the coil L of the RFID tag 100, i.e., when adjusting the impedance value of the inductance L, a notch 5 may be provided in a part of the hanging portion 3 in the vicinity of the inductance L of the RFID tag, as shown in FIG.

[0033] Furthermore, the shape of the RFID cover 1 may be changed according to the shape of the director element 20 of the plate-shaped antenna 10. For example, if the shape of the director element 20 of the plate-shaped antenna 10 is circular or elliptical, the shape of the RFID cover 1 may also be circular or elliptical. If the cross section along the vertical direction of the director element 20 of the plate-shaped antenna 10 is arc-shaped, the cross section along the vertical direction of the RFID cover 1 may also be arc-shaped. 1(c), when the RFID cover 1 is attached to the RFID tag 100, a gap 6 is formed between the lower end of the hanging portion 3 and the second main surface in a side view. By providing the gap 6, even when the RFID tag 100 is attached to a conductor such as a metal plate, it is possible to prevent the RFID cover 1 from coming into contact with the metal plate or the like and causing a short circuit. Furthermore, when an elastic material such as polystyrene foam is used as the first insulating base material 40, when an external force is applied to the RFID cover 1, the polystyrene foam or the like can be elastically deformed by utilizing the gap 6, so that it is possible to prevent the RFID tag 100 from being damaged by the external force. In this embodiment, the planar inverted F antenna 10 has been used as the planar antenna, but the RFID cover 1 of the present invention can also be applied to a general F-shaped antenna having a planar waveguide element. [Industrial Applicability]

[0034] INDUSTRIAL APPLICABILITY The present invention provides a thin RFID cover with a waveguide function and an RFID tag set that can improve the impact resistance of an RFID tag, and has industrial applicability. [Explanation of symbols]

[0035] L inductor pattern 1. RFID cover with wave guide function 2 Main unit 3 Hanging part 4 Coupling Capacitors 5 Notch 6. Gap 10 Plate-shaped antenna (plate-shaped inverted F antenna) 11 Coating layer 12 Base 20 First director element 21 Recess 30 Second director element 40 First insulating substrate 50 Power supply unit 60 Short circuit 80 IC chips 93 Capacitor 100 RFID Tags 200 RFID tag sets

Claims

1. A conductive RFID cover with a waveguide function is used for an RFID tag having a plate-shaped antenna that receives radio waves transmitted from a reader and an IC chip that operates based on the radio waves. The antenna includes a main body covering a surface of a director element of the plate-like antenna, and a hanging portion hanging down from a side of the main body, At least the front and side surfaces of the RFID tag are covered with a coating layer made of an insulating material; the main body portion covers a surface of the director element via the coating layer, and the hanging portion covers a side surface of the director element via the coating layer, a coupling capacitor including an air layer is formed by the body portion, the hanging portion, the coating layer, and the waveguide element; The coupling capacitor is capacitively coupled with the capacitor of the RFID tag to form a resonant circuit with the inductor pattern of the RFID tag, thereby functioning as part of the plate-shaped antenna.

2. 2. The RFID cover with waveguide function according to claim 1, characterized in that a part of the hanging portion is provided with a notch.

3. 3. The RFID cover with waveguiding function according to claim 1, wherein the plate-shaped antenna is a plate-shaped inverted F antenna.

4. the planar inverted-F antenna comprises a first insulating substrate having a first principal surface and a second principal surface opposite to the first principal surface, a first waveguide element provided on the first principal surface, a second waveguide element provided on the second principal surface, a power feeding section having one end electrically connected to the second waveguide element, and a short circuit having one end electrically connected to the first waveguide element and the other end electrically connected to the second waveguide element, and receives the radio waves via the first insulating substrate, the first waveguide element, the second waveguide element, the power feeding section, and the short circuit, an inductor pattern formed by the first director element, the short-circuit portion, the second director element, and the power supply portion, and a capacitor formed by the first director element, the second director element, and the first insulating base material form a resonant circuit that resonates in a frequency band of the radio wave, the main body and the hanging portion cover the first waveguide element via the coating layer, 4. The RFID cover with waveguide function according to claim 3, wherein the coupling capacitor including the air layer and the capacitor are capacitively coupled.

5. 5. The RFID cover with waveguide function according to claim 4, wherein when viewed from the side, with the main body and the hanging portion covering the first waveguide element via the coating layer, there is a gap between a lower end of the hanging portion and the second principal surface.

6. 5. The RFID cover with waveguide function according to claim 4, wherein the first insulating base material is made of an elastic material.

7. An RFID tag set including an RFID tag having a plate-shaped antenna for receiving radio waves transmitted from a reader and an IC chip for operating based on the radio waves, and an RFID cover with wave guiding function according to claim 1 for use with the RFID tag, The plate antenna is a plate inverted-F antenna, the planar inverted-F antenna comprises a first insulating substrate having a first principal surface and a second principal surface opposite to the first principal surface, a first waveguide element provided on the first principal surface, a second waveguide element provided on the second principal surface, a power feeding section having one end electrically connected to the second waveguide element, and a short circuit having one end electrically connected to the first waveguide element and the other end electrically connected to the second waveguide element, and receives the radio waves via the first insulating substrate, the first waveguide element, the second waveguide element, the power feeding section, and the short circuit, an inductor pattern formed by the first director element, the short-circuit portion, the second director element, and the power supply portion, and a capacitor formed by the first director element, the second director element, and the first insulating base material form a resonant circuit that resonates in a frequency band of the radio wave, the main body and the hanging portion cover the first waveguide element via the coating layer, An RFID tag set, characterized in that the coupling capacitor including the air layer and the capacitor are capacitively coupled.

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