JP5347379B2 - RFID communication apparatus, RFID communication gate, and RFID communication method - Google Patents

Description

The present invention relates to an RFID communication device and an RFID communication gate for communicating with an RFID tag (IC tag), and more specifically, a radio wave reflector for reflecting radio waves radiated from an antenna toward the RFID tag. The present invention relates to an RFID communication device, an RFID communication gate, and an RFID communication method.

In recent years, RFID communication devices and RFID communication gates for communicating with RFID tags have become widespread. This type of RFID communication apparatus includes an antenna that radiates radio waves toward the RFID tag and catches response radio waves from the RFID tag.
For example, the RFID communication gate 201 shown in FIG. 13 has antennas 203 on the column portions 202 standing on the left and right sides of the gate passage area, and communicates with the RFID tag by sequentially switching the antennas 203. It is like that.
However, since the radiation range of the radio wave is narrow in the vicinity of the antenna 203, many antennas 203 are required to radiate the radio wave to the entire area in the gate.
For this reason, the increase in the number of antennas not only increases the cost, but also increases the switching time of the antenna 203 and may decrease the reading performance of the RFID tag that moves at high speed.

  Therefore, an RFID communication device including a radio wave reflector that reflects radio waves radiated from an antenna toward an RFID tag has been proposed (for example, see Patent Document 1). According to such an RFID communication apparatus, it is possible to widen the radio wave radiation range in the vicinity while reducing the number of antennas, so that not only the cost can be reduced, but the switching time of the antenna is reduced and the RFID tag that moves at high speed Reading performance can be improved.

JP 2006-345463 A

However, in a conventional RFID communication device using a radio wave reflector, it is difficult to specify the reading range of the RFID tag while ensuring the necessary electric field strength. There was a possibility that miscommunication would occur.
Specifically, as shown in FIG. 14, a radio wave reflector 204 (length 1.5λ or more, preferably 2λ (λ is about 35 cm in the case of 860 MHz band) in the vicinity of the antenna 203 (for example, offset = 0.6 m). ) And the radio wave radiated from the antenna 203 in the vertical direction at a radiation angle of 65 ° is reflected horizontally by the radio wave reflector 204 and radiated to the radio wave receiving surface (distance = 2.5 m). The reflected radiation angle 204 becomes 65 °, and the radiation angle suppressing action cannot be obtained.

Further, as shown in FIG. 15, a radio wave reflector 204 (length 1.5λ or more, preferably 2λ) is installed far away from the antenna 203 (for example, offset = 1.2 m or more), and radiates from the antenna 203 in the vertical direction. When radio waves radiated at an angle of 65 ° are reflected in the horizontal direction by the radio wave reflector 204 and radiated to the radio wave receiving surface (distance = 2.5 m), the reflected radiation angle of the radio wave reflector 204 is about 30 °. It becomes possible to suppress the corner.
However, as shown in FIG. 15, among the radio waves radiated from the antenna 203, many radio waves that are not reflected by the radio wave reflection plate 204 are wasted, and the electric field strength is reduced.

In order to suppress the spread of the reflected wave of the radio wave reflector, it is conceivable to make the radio wave reflector smaller than 1.5λ.
However, in this case, as shown in FIG. 16, since diffraction and scattering of radio waves increase, it is difficult not only to suppress the spread of radio waves as a result, but also the electric field strength becomes weak due to the reduction of the reflection area. Problem arises.
In addition, in order to suppress the spread of the reflected wave of the radio wave reflector, it is possible to use a parabolic reflector having a paraboloidal surface or an elliptical surface as a reflection surface, or a plurality of radio wave reflectors installed at different angles. However, in this case, not only the cost increases, but also the positional relationship with the antenna needs to be adjusted with high accuracy and the accuracy needs to be maintained.
Furthermore, in the RFID communication gate in which the arrangement of the antenna and the radio wave reflector is restricted, there is a problem that it is very difficult to install a parabolic reflector and a plurality of radio wave reflectors.

  The present invention has been considered in view of the above circumstances, specifies the reading range of the RFID tag while ensuring the necessary electric field strength, and suppresses leakage of radio waves and erroneous communication with the RFID tag outside the reading range. An object of the present invention is to provide an RFID communication device, an RFID communication gate, and an RFID communication method.

  In order to achieve the above object, an RFID communication device of the present invention is an RFID communication device provided with a radio wave reflector that reflects radio waves radiated from an antenna toward an RFID tag, and the radio wave reflector is substantially flat. The reflection surface portion has a reflected wave focusing pattern in which a portion where the reflected wave intensifies the intensity and / or a portion where the reflected wave weakens the intensity is positively formed to focus the reflected wave in a predetermined direction.

  In order to achieve the above object, the RFID communication gate of the present invention is an RFID communication gate provided with a radio wave reflection plate that reflects radio waves radiated from an antenna toward an RFID tag in a gate passing region. The radio wave reflector is a reflection that focuses the reflected wave in a predetermined direction by actively creating a portion where the reflected wave intensifies the intensity and / or a portion where the reflected wave weakens the intensity on the substantially flat reflecting surface portion. The configuration has a wave focusing pattern.

  Furthermore, in order to achieve the above object, an RFID communication method of the present invention is an RFID communication method for performing communication by reflecting a radio wave radiated from an antenna toward an RFID tag by a radio wave reflector. The reflected wave of the radio wave radiated from the antenna is predetermined by the reflected wave focusing pattern formed on the substantially flat reflecting surface portion and having a portion where the reflected wave increases the intensity and / or a portion where the reflected wave weakens the intensity. As a method of focusing in the direction.

  According to the present invention, it is possible to specify the reading range of the RFID tag while ensuring the required electric field strength, and to suppress leakage of radio waves and erroneous communication with the RFID tag outside the reading range.

Hereinafter, preferred embodiments of an RFID communication device, an RFID communication gate, and an RFID communication method of the present invention will be described with reference to the drawings.
[RFID communication device]
First, an RFID communication apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic side view of an RFID communication apparatus (a wave absorbing wall is omitted) according to an embodiment of the present invention.
2A is a front view of the radio wave reflector of the present embodiment, and FIG. 2B is an XX cross-sectional view of the radio wave reflector shown in FIG.
FIG. 3 is a schematic front view of a radio wave reflecting plate showing another embodiment of the reflected wave focusing pattern.

As shown in these drawings, the RFID communication device 1 according to an embodiment of the present invention directs radio waves (broken arrows shown in FIG. 1) radiated from an antenna 2 toward a predetermined RFID tag (not shown). A radio wave reflector 3 for reflection is provided.
The radio wave reflector 3 has a substantially flat reflecting surface portion, and the reflecting surface portion positively creates a portion where the reflected waves intensify the intensity and / or a portion where the reflected waves weaken the intensity. A reflected wave focusing pattern 4 for focusing the light in a predetermined direction is formed.
Specifically, as shown in FIG. 2, the radio wave reflecting plate 3 includes a plurality of radio wave absorbers 6 formed in a strip shape arranged in parallel on a reflecting plate 5 serving as a base, And a wave absorbing portion are alternately formed, and a reflected wave focusing pattern 4 having a cylindrical Fresnel lens pattern shape is formed in which the width of the radio wave reflecting portion becomes narrower toward the outside.
For example, the reflected wave focusing pattern 4 can be formed by sticking a radio wave absorbing sheet (tape) on the base reflector material so as to draw a cylindrical Fresnel lens pattern.

According to such a reflected wave focusing pattern 4, a sufficient reflection area is ensured on the center side in the width direction of the radio wave reflector 3, so that the reflected waves intensify each other, and the width direction of the radio wave reflector 3 Since the reflection area is suppressed on the outer end side, the reflected waves weaken each other. As a result, it is possible to focus the reflected wave in the width direction of the radio wave reflector 3 without focusing the reflected wave in the length direction of the radio wave reflector 3.
In addition, the radio wave reflecting plate 3 can be provided with radio wave absorbing walls 9 extending in the radio wave reflecting direction at both ends in the width direction as shown in FIG. 2 (not shown in FIG. 1). By providing such a radio wave absorbing wall 9, it is possible to further improve directivity and prevent diffraction of radio waves.
In this way, the RFID reflector can have an effect similar to that of an active phased array antenna by using super-resolution technology, and a low-cost and highly reliable RFID communication device can be realized. can do.

In the reflected wave focusing pattern 4, the radio wave reflection part and the radio wave absorption part are arranged in parallel in the far field 7 from the antenna 2, but in the near field 8, the interval is adjusted according to the distance from the antenna 2. It is preferable.
For example, as shown in FIG. 3, the distance between the radio wave reflecting portion and the radio wave absorbing portion can be increased as the distance from the antenna 2 becomes smaller, and a divergent non-parallel arrangement can be achieved.

The reflected wave focusing pattern 4 is formed using one or a plurality of materials among a material that reflects radio waves, a material that absorbs radio waves, a material that has periodicity according to the wavelength of the radio waves, and a material that scatters radio waves. Can do.
As a material that reflects radio waves, for example, metals such as aluminum and iron can be used, and as a material that absorbs radio waves, for example, ferrite, radio wave absorber (fine metal confined with resin), etc. are used. be able to.
In addition, as a material having periodicity according to the wavelength of radio waves, for example, a material having a uniform dielectric constant can be used, and as a material for scattering radio waves, for example, metals such as aluminum and iron, Water such as water can be used.
Hereinafter, a specific configuration example of the reflected wave focusing pattern 4 by a combination of a material that reflects radio waves and a material that absorbs radio waves will be described.

FIG. 4 is a cross-sectional view showing a configuration example 1 of the reflected wave focusing pattern.
FIG. 5 is a cross-sectional view showing a configuration example 2 of the reflected wave focusing pattern.
Further, FIG. 6 is a cross-sectional view showing a configuration example 3 of the reflected wave focusing pattern.
The reflected wave focusing pattern 4 shown in FIG. 4 has a band-like reflector 11 on a flat wave absorber 10 and the phase difference of reflected waves is 0 at the center of the two reflectors 11 and 1/2 at both ends. -It is configured by installing at intervals in the horizontal direction so as to be λ.
Specifically, the distance from the center of one reflector 11 to the center of the adjacent reflector 11 is 1 · λ + (λ × integer) times (the phase is the same), for example, {λ, 2λ, 3λ. } At both ends, ½ · λ + (λ × integer) times (phase is shifted by 180 °), for example, {0.5λ, 1.5λ, 2.5λ,. As a result, a portion where the reflected waves from the reflector 11 are added and strengthened (center side) and a portion where the reflected waves are subtracted and weakened (both ends) are created.

The reflected wave focusing pattern 4 shown in FIG. 5 has a building material 13 having a thickness of about 1/2 · λ (when the permittivity is about 1) on a flat main reflector 12 (in terms of radio waves, empty urethane, The band-shaped sub-reflector 14 is installed with a polystyrene foam or the like in between.
As a result, a portion is added and strengthened by the phase difference from the reflected wave of the sub-reflector 13 at the center of the main reflector 12.

Similar to FIG. 5, the reflected wave focusing pattern 4 shown in FIG. 6 sandwiches a building material 13 having a thickness of about ½ · λ (when the dielectric constant is about 1) on a flat main reflector 12. A band-shaped sub-reflecting plate 14 is installed, and side sub-reflecting plates 15 are installed on both the left and right sides of the sub-reflecting plate 14 at a distance of ¼ · λ in the vertical direction from the main reflecting plate 12.
If it does in this way, since it interferes with the reflected wave reflected outward from the main reflector 12 and weakens the intensity, the spread of the reflected wave outward can be suppressed and the directivity in the width direction can be further enhanced. .

Here, the side sub-reflecting plates 15 shown in FIG. 6 may be arranged one by one at both ends of the radio wave reflecting plate 3, and are arranged one by one on the left and right sides of one sub-reflecting plate 14. May be. In the former case, although the reflection efficiency is good, there are few reflected waves that cancel each other, so the effect of suppressing radio wave diffusion is low. On the contrary, in the latter case, the effect of suppressing radio wave diffusion is high, but the reflection efficiency is low. Therefore, these arrangement patterns can be customized according to the system to be mounted.
5 and 6 may be equidistant in the horizontal direction, but is preferably adjusted according to the distance from the antenna 2. That is, as the distance from the antenna 2 to the left and right is increased, the incident angle is narrowed, and the distance between the adjacent wavelengths is increased accordingly, so that the interval is widened at a portion close to the antenna 2 and the interval is gradually narrowed at a distant portion. Placement adjustments can be made.

FIG. 7 is a diagram showing a cross-sectional configuration example of the radio wave reflector, where (a) is a cross-sectional view of the radio wave reflector made up of a flat plate-like reflector and a belt-like radio wave absorbing sheet, and (b) is a flat plate shape. (C) is a cross-section of a radio wave reflector made up of a flat plate-like reflector, a belt-like wave reflector sheet, and a building material. The figure is shown.
As shown in these drawings, the radio wave reflector 3 of the present invention can be formed using various materials, and constitutes an optimal radio wave reflector 3 according to antenna characteristics, installation environment, and the like. be able to.
Specifically, as shown in FIG. 7 (a), the radio wave reflecting plate 3 composed of a flat plate-like reflecting plate 16 and a belt-like wave absorbing sheet 17, or as shown in FIG. The radio wave reflecting plate 3 constituted by the radio wave absorbing plate 18 and the belt-like radio wave reflecting sheet 19 uses a material that absorbs radio waves, so that the use efficiency of radio waves is low.
On the other hand, the radio wave reflector 3 shown in FIG. 7C is composed of a flat reflector 20, a belt-like radio wave reflector 21 and a building material 22 without using a material that absorbs radio waves. The radio wave usage efficiency can be dramatically improved.

FIG. 8 is an explanatory view schematically showing the operating principle of the reflected wave focusing pattern by the radio wave reflector 3 according to the present embodiment, and (a) is an explanatory view of the reflected wave focusing pattern (horizontal configuration) of the minimum configuration, (B) is also explanatory drawing of the reflected wave focusing pattern (vertical structure) of the minimum structure similarly.
Specifically, FIG. 8 shows the reflected wave focusing pattern 4 having the minimum configuration, and the reflected wave focusing pattern 4 shown in FIG. 8A has the side sub-reflecting plates 24 arranged on the left and right sides of the main reflecting plate 23. Configured. This reflected wave focusing pattern can suppress the spread of the reflected wave from the main reflecting plate 23 by having the same action as the assist bar in the state-of-the-art semiconductor reticle.
Further, the reflected wave focusing pattern 4 shown in FIG. 8B is obtained by installing a band-shaped sub-reflecting plate 27 on a flat main reflecting plate 25 with a building material 26 sandwiched therebetween, and the reflected wave focusing of a vertical configuration. The pattern has a minimum configuration.

Next, the operation of the radio wave reflector 3 of the present embodiment having the above configuration will be described.
The radio wave radiated from the antenna 2 is reflected by the radio wave reflector 3 and communicates with the RFID tag.
For example, the radio wave reflector 3 has a reflected wave focusing pattern 4 as shown in FIG. In this case, the radio wave from the antenna 2 is reflected by the main reflector 12, the sub reflector 14 and the side sub reflector 15.

Since the main reflector 12 and the sub-reflector 14 are installed with a distance of ½ · λ, the phase difference between the reflected waves is λ and is added to strengthen the center.
On the other hand, since the side sub-reflection plate 15 is installed at a distance of 1/4 · λ from both the main reflection plate 12 and the sub-reflection plate 14, the reflected wave from the main reflection plate 12 and the side sub-reflection plate 15 is provided. The phase difference is 1/2 · λ and is subtracted from each other to weaken at both ends.
Further, since the phase difference between the reflected waves from the sub-reflecting plate 14 and the side sub-reflecting plate 15 is also 1/2 · λ, it is similarly subtracted at both ends and weakened.
As a result, the reflected wave from the reflecting plate 3 becomes strong at the center, and the reflected wave spreading outwards is canceled and weakened, so that leakage of radio waves and erroneous communication with RFID tags outside the reading range can be suppressed. It becomes possible.

In addition, when the radio wave from the antenna 2 is incident on the radio wave reflector 3 at an angle, there is a difference in the distance to the radio wave reflector 3 near and far depending on the incident angle.
In this case, it is preferable to change the vertical distance between the reflectors 12, 14, and 15 in accordance with the incident angle in order to correct the difference in distance between the vicinity and the distance with different incident angles.
For example, as shown in FIG. 9, the thickness of the building material 13 is changed, and the vertical distance between the reflecting plates 12, 14, 15 is adjusted.
Alternatively, as shown in FIG. 10, by changing the dielectric constant (ε) of the building material 13 without changing the thickness of the building material 13 that separates the reflecting plates 12, 14, 15 from each other in the vertical direction, 2 · λ and 1/4 · λ may be created.

According to the RFID communication apparatus 1 of the present embodiment configured as described above, the following effects can be obtained.
The first effect is an improvement in the reading rate. The reason for this is that compared with the case of using a normal flat reflector, the reflected wave is focused and the electric field strength is increased, improving the reading rate in the reading range, while reducing the radio wave leakage and overreading outside the reading range. This is because it is suppressed.
The second effect is reduction of radio wave leakage. The reason is that the radio waves are focused at the time of reflection and unnecessary side lobes are canceled.
The third effect is the ease of arrangement and processing of the radio wave reflector 3. The reason is that the reflection surface portion of the radio wave reflection plate 3 is substantially flat.
A fourth effect is that a wide reading range can be secured as compared with the number of antennas 2. This is because the reflected wave in the width direction is focused without focusing the reflected wave in the length direction.
The fifth effect is an improvement in reading performance during high-speed conveyance. This is because the switching time of the antenna 2 is reduced by reducing the number of antennas.

  As described above, in the RFID communication apparatus 1 according to the present embodiment, an effect similar to that of an active phased array antenna can be obtained by using a super-resolution technique as an RFID reflector, and the price is low. Thus, a highly reliable RFID communication device can be realized.

[Gate for RFID communication]
Next, an RFID communication gate according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 11 is a schematic perspective view of the RFID communication gate according to the first embodiment of the present invention, and FIG. 12 is a schematic perspective view of the RFID communication gate according to the second embodiment of the present invention.
As shown in FIGS. 11 and 12, the RFID communication gate 30 includes a radio wave reflector 3 that reflects radio waves radiated from the antenna 2 toward an RFID tag (not shown) in the gate passing area. The radio wave reflecting plate 3 actively forms a portion where the intensity of the reflected wave intensifies and / or a portion where the intensity of the reflected wave weakens on the substantially flat reflection surface portion, and focuses the reflected wave in a predetermined direction. A reflected wave focusing pattern 4 is provided.

Specifically, one (see FIG. 11) or two (see FIG. 12) radio wave reflectors 3 are arranged along the left and right support columns 31 standing on the left and right sides of the gate passage area. The radio wave from the antenna 2 arranged on the upper end side (or the lower end side) of the support column 31 is reflected toward the gate passing region.
The reflected wave focusing pattern 4 focuses reflected waves in the front-rear direction of the gate passing region without focusing the reflected waves in the height direction of the gate passing region.
In addition to the above configuration, the radio wave reflector 3 and the reflected wave focusing pattern 4 provided in the RFID communication gate 30 are the same as the radio wave reflector 3 and the reflected wave focusing pattern 4 according to the embodiment of the present invention described above. Therefore, detailed description is omitted.
With this configuration, in the RFID communication gate 30 of the present embodiment, the number of radio wave reflectors 3 can be reduced to reduce costs, and the reading range can be optimized.

Thus, according to the RFID communication gate 30 according to the present embodiment, the radio wave reflector 3 of the present invention specifies the reading range of the RFID tag while securing the necessary electric field strength, It is possible to suppress erroneous communication with an RFID tag outside the reading range.
That is, in the RFID communication gate 30 of the present embodiment, the horizontal reflection of the radio wave as realized by the phased array antenna is realized by using a super-resolution technique for the RFID reflector, Low-cost and highly reliable RFID communication gates can be realized by arranging reflectors on the left, right, top and bottom as needed and using these reflectors to ensure a vertical radiation angle. Can be provided.

The RFID communication device, the RFID communication gate, and the RFID communication method of the present invention have been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and the scope of the present invention. Needless to say, various modifications can be made.
For example, the application target of the RFID communication device, the RFID communication gate, and the RFID communication method of the present invention is not particularly limited.

The application object of the present invention is, for example, a place where a plurality of RFID communication devices are arranged, and prevention of leakage / misreading is important, for example, a truck terminal, a distribution warehouse, a passage of an automatic warehouse, and loading and unloading of luggage. It can be suitably used in the field.
In addition, one RFID communication device is placed in a narrow space, and there is a requirement for installation space, automatic merchandise settlement equipment such as shops that should not read RFID tags outside the reading range, people, cars, etc. It can also be applied to entrances and exits, as well as entrances and exits of temporary store warehouses and temporary warehouses.

  The present invention can be suitably used for an RFID communication device or an RFID communication gate provided with a radio wave reflector that reflects radio waves radiated from an antenna toward an RFID tag.

1 is a schematic side view of an RFID communication apparatus according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS (a) of the RFID communication apparatus which concerns on one Embodiment of this invention is a front view of a radio wave reflecting plate, (b) is XX sectional drawing of the radio wave reflecting plate shown to (a). It is a schematic front view of the electromagnetic wave reflector which shows other embodiment of the reflected wave focusing pattern of this invention. It is sectional drawing which shows the structural example 1 of the reflected wave focusing pattern of this invention. It is sectional drawing which shows the structural example 2 of the reflected wave focusing pattern of this invention. It is sectional drawing which shows the structural example 3 of the reflected wave focusing pattern of this invention. It is a figure which shows the cross-sectional structural example of the electromagnetic wave reflecting plate of this invention, (a) is sectional drawing of the electromagnetic wave reflecting plate comprised by the flat reflector and the strip | belt-shaped electromagnetic wave absorption sheet, (b) is flat shape. (C) is a cross section of a radio wave reflector made up of a flat plate reflector, a belt-like wave reflector sheet, and a building material. FIG. It is explanatory drawing which shows typically the operation principle of the reflected wave focusing pattern by the electromagnetic wave reflector which concerns on one Embodiment of this invention, (a) is explanatory drawing of the reflected wave focusing pattern (horizontal structure) of minimum structure, (b) ) Is an explanatory view of the reflected wave focusing pattern (vertical configuration) having the minimum configuration. One Embodiment of the electromagnetic wave reflector provided with the function which correct | amends the distance difference of the near and far distance from which an incident angle differs is shown, (a) is sectional drawing, (b) is the top view. It is sectional drawing which shows other embodiment of the electromagnetic wave reflector provided with the function which correct | amends the distance difference of the near and distant from which incident angle differs. 1 is a schematic perspective view of an RFID communication gate according to a first embodiment of the present invention. It is a schematic perspective view of the RFID communication gate according to the second embodiment of the present invention. It is a schematic perspective view of the gate for RFID communication which concerns on a prior art example. It is operation | movement explanatory drawing of the electromagnetic wave reflector which concerns on a prior art example. It is operation | movement explanatory drawing of the electromagnetic wave reflector which concerns on a prior art example. It is operation | movement explanatory drawing of the electromagnetic wave reflector which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 RFID communication apparatus 2 Antenna 3 Radio wave reflector 4 Reflected wave focusing pattern 30 RFID communication gate 31 Support | pillar part

Claims (6)

An RFID communication apparatus provided with a radio wave reflector that reflects radio waves radiated from an antenna toward an RFID tag,
The radio wave reflecting plate has a reflection wave focusing pattern for focusing a reflected wave in a predetermined direction on a substantially flat reflecting surface part, including a part where reflected waves increase in intensity and / or a part where reflected waves weaken intensity. Have
The reflected wave focusing pattern is configured by installing two or more radio wave reflectors that are separated in the vertical direction in order to generate a phase difference of 1/2 · λ, λ, and other reflected waves. Further, an RFID communication apparatus characterized in that the vertical distance between the radio wave reflectors is changed in accordance with the incident angle in order to correct a difference in distance between the vicinity and the distant where the incident angles are different. An RFID communication apparatus provided with a radio wave reflector that reflects radio waves radiated from an antenna toward an RFID tag,
The radio wave reflecting plate has a reflection wave focusing pattern for focusing a reflected wave in a predetermined direction on a substantially flat reflecting surface part, including a part where reflected waves increase in intensity and / or a part where reflected waves weaken intensity. Have
The reflected wave focusing pattern is configured by installing two or more radio wave reflectors that are separated in the vertical direction in order to generate a phase difference of 1/2 · λ, λ, and other reflected waves. Furthermore, in order to correct a difference in distance between near and far different incident angles, the dielectric constant of the building material separating the radio wave reflectors in the vertical direction is changed according to the incident angle. . The reflected wave focusing pattern is formed using one or a plurality of materials among a material that reflects radio waves, a material that absorbs radio waves, a material that has periodicity according to the wavelength of radio waves, and a material that scatters radio waves. The RFID communication apparatus according to claim 1 or 2 , wherein An RFID communication gate provided with a radio wave reflection plate that reflects radio waves radiated from an antenna toward an RFID tag in a gate passing area,
The radio wave reflecting plate has a reflection wave focusing pattern for focusing a reflected wave in a predetermined direction on a substantially flat reflecting surface part, including a part where reflected waves increase in intensity and / or a part where reflected waves weaken intensity. Have
The radio wave reflectors are arranged one by one along the left and right struts erected on both the left and right sides of the gate passage region, and receive radio waves from the antennas disposed on the upper end side or the lower end side of the strut portions. Reflect towards the gate passage area,
The RFID communication gate, wherein the reflected wave focusing pattern focuses the reflected wave in the front-rear direction of the gate passing region without focusing the reflected wave in the height direction of the gate passing region. An RFID communication method for performing communication by reflecting radio waves radiated from an antenna toward an RFID tag by a radio wave reflector,
The reflected wave focusing pattern formed on the substantially flat reflecting surface portion of the radio wave reflector, where the reflected waves intensify the intensity and / or where the reflected waves intensify the intensity of the reflected wave, emits the radio wave radiated from the antenna. When focusing the reflected wave in a predetermined direction,
The reflected wave focusing pattern is configured by installing two or more radio wave reflectors separated in the vertical direction in order to generate a phase difference of 1/2 · λ, λ, and other reflected waves. Furthermore, in order to correct the difference in distance between the vicinity and the distance with different incident angles, the RFID communication method is characterized in that the vertical distance between the radio wave reflectors is changed according to the incident angle. An RFID communication method for performing communication by reflecting radio waves radiated from an antenna toward an RFID tag by a radio wave reflector,
The reflected wave focusing pattern formed on the substantially flat reflecting surface portion of the radio wave reflector, where the reflected waves intensify the intensity and / or where the reflected waves intensify the intensity of the reflected wave, emits the radio wave radiated from the antenna. When focusing the reflected wave in a predetermined direction,
The reflected wave focusing pattern is configured by installing two or more radio wave reflectors separated in the vertical direction in order to generate a phase difference of 1/2 · λ, λ, and other reflected waves. Furthermore, in order to correct a difference in distance between near and far different incident angles, a dielectric constant of a building material that separates the radio wave reflectors in the vertical direction is changed according to the incident angle. .

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