JP2008078882A - Antenna device and its article housing for neighboring communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently conduct radio communications with a communication object such as a large number of radio tags arranged in the neighborhood. <P>SOLUTION: First leakage transmission lines 4 and second ones 5 are disposed in parallel while mutually arranging terminals along the longitudinal direction on the surfaces of shelf boards forming each shelf of a bookshelf. The terminal sections of the first leakage transmission lines 4 are opened, and the terminal sections of the second ones 5 are short-circuited by a short-circuit member 11. The first and second leakage transmission lines 4 and 5 are connected to a switching appliance 8 through cables. The switching appliance is connected to a radio-tag reader 10. When the radio-tag reader reads recording data from a large number of the radio tags stuck on books on the bookshelf, it alternately changes over the first and second leakage transmission lines 4 and 5 and uses them as antennas. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a near field communication antenna device and an article container used in, for example, a radio communication apparatus that performs radio communication with a radio tag attached to an article.

2. Description of the Related Art Conventionally, there is a system for managing articles such as books and CDs by arranging them on a shelf. There is known one in which tag recording data is read one by one by a handy scanner and transmitted to a personal computer for management (see, for example, Patent Document 1).
In addition, there is a book management system for managing the position of books stored or displayed on bookshelves or sales floors in libraries, bookstores, etc., and when an act of storing books in a bookshelf is performed, an IC tag attached to the book is placed on the bookshelf Is known to be able to acquire information from an IC tag reader from an IC tag reader and recognize that a book is stored in a bookcase (for example, see Patent Document 2). ).
JP 2004-102947 A JP 2005-182352 A

However, conventionally, the communication with the wireless tag attached to a plurality of books on the bookshelf is read one by one using an antenna provided on the handy scanner, so that the work efficiency is poor. was there.
In addition, when reading a wireless tag attached to a plurality of books on the bookshelf using a wireless tag reader installed on the bookshelf, there is a low part in the electric field intensity of the radio wave transmitted from the wireless tag reader. For this reason, there is a case where a wireless tag that cannot read data may be generated, and there is a problem that reading efficiency is low.

  Therefore, the present invention provides a near field communication antenna apparatus capable of efficiently performing wireless communication with a communication target such as a large number of wireless tags arranged in the vicinity.

  The present invention relates to a first leaky transmission line having a terminal portion opened in parallel and a second leaky transmission line in which the terminal portion is short-circuited, and a leaky transmission line to a wireless communication device during communication. It is in the antenna device for near field communication provided with the switch connected to switching.

  ADVANTAGE OF THE INVENTION According to this invention, the antenna apparatus for near field communication which can perform efficiently radio | wireless communication with communication objects, such as many radio tags arrange | positioned in the vicinity, can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIGS. 1 and 2, a large number of books 2 are stored side by side as articles in a book shelf 1 that is an article storage device. A wireless tag 3 is attached to the back of each book 2.

  A first leakage transmission path 4 and a second leakage transmission path 5 are arranged in parallel along the longitudinal direction on the surface of a shelf plate forming each shelf which is an article storage section of the book shelf 1. As each of the leaky transmission lines 4 and 5, for example, balanced two wires called feeder wires are used. In addition, a leaky coaxial cable, a microstrip line, or the like can be used. The balanced two wires can be used as an antenna due to leaked radio waves at a short distance.

  One end of each of the first and second leaky transmission lines 4 and 5 is connected to a switch 8 which is a switching means attached to one side surface of the bookcase 1 via cables 6 and 7 such as coaxial cables. And the said switch 8 is connected to the RFID tag reader 10 which is a radio | wireless communication apparatus similarly attached to the one side of the said bookshelf 1 via the cables 9, such as a coaxial cable.

  As shown in FIG. 3, the first leaky transmission line 4 and the second leaky transmission line 5 are arranged in parallel with the entire length being a and the ends being aligned with each other. In contrast, the second leakage transmission path 5 is short-circuited by a short-circuit member 11 in the second leakage transmission path 5. In addition, as a short circuit, not only the short circuit by the short circuit member 11, but the termination | terminus by the characteristic impedance of a leaky transmission path, and the termination | terminus by resistance may be sufficient.

  In such a configuration, the signal transmitted from the wireless tag reader 10 is transmitted through the first and second leaky transmission lines 4 and 5 as a traveling wave of the wavelength λg. The signal transmitted through the leaky transmission line is reflected at the end of the first and second leaky transmission lines 4 and 5, and is transmitted through the leaky transmission lines 4 and 5 as a backward wave of the wavelength λg. In the leaky transmission lines 4 and 5, a traveling wave and a backward wave are combined to generate a standing wave having a period λg / 2. The electric field strength in the vicinity due to the radio waves leaking from the first and second leaky transmission lines 4 and 5 varies with the same period λg / 2 as the standing wave, as indicated by the solid line e1 and the dotted line e2. In addition, since the terminal portion of the first leaky transmission path 4 is opened and the terminal portion of the second leaky transmission path 5 is short-circuited, the distribution positions of the electric fields due to the radio waves are shifted by λg / 4. In other words, the electric field intensity e1 due to the radio wave in the first leaky transmission path 4 and the electric field intensity e2 due to the radio wave in the second leaky transmission path 5 vary so as to complement each other's low electric field strength.

  Therefore, when the wireless tag reading device 10 reads the recorded data from the wireless tag 3 attached to the book 2 arranged on the bookshelf 1, the switch 8 is controlled so that, for example, the first leakage transmission path 4 is used as an antenna. Connecting. In this state, the wireless tag reader 10 sequentially reads recorded data from the wireless tag 3 of each book 2.

  However, since the electric field strength e1 of the first leaky transmission line 4 has a low portion, the wireless tag 3 that cannot read the recorded data is generated. Therefore, the wireless tag reader 10 controls the switch 8 and this time connects the second leaky transmission line 5 as an antenna. In this state, the wireless tag reader 10 sequentially reads recorded data from the wireless tag 3 of each book 2. As a result, the recording data can be read from the wireless tag 3 that could not be read by the first leaky transmission path 4.

  Thus, the recording data can be read from the wireless tags 3 of all the books 2 arranged on the bookshelf 1 by alternately using the first leakage transmission path 4 and the second leakage transmission path 5 as antennas. become. As described above, the first leaky transmission path 4 and the second leaky transmission path 5 are alternately switched and used, thereby efficiently communicating with the wireless tags 3 of all the books 2 arranged on the bookshelf 1. The wireless tag reader 10 can read the recorded data of the wireless tag with almost no burden on the operator.

  As described above, the wireless tag reader 10 controls the switching device 8 to read the recorded data from the wireless tag 3 of the book 2, but the switching frequency of the switching device 8 always confirms the existence of each book 2. In such a case, it is frequently performed, and in the case of confirming the existence of each book 2 only in a specific time zone, it is performed only in that time zone. That is, the switching frequency of the switch 8 is determined by the way of managing the book 2.

(Second Embodiment)
In this embodiment, a modification of the second leaky transmission line will be described. Other configurations are the same as those of the first embodiment.
As shown in FIG. 4, instead of the configuration in which the end portion of the balanced two wires is short-circuited as the second leaky transmission line, the end portion of the balanced two wires is opened, and the length is longer than that of the first leaky transmission line 4. The shortened second leaky transmission line 51 is used.

That is, the start ends of the first and second leaky transmission lines 4 and 51 are aligned and arranged in parallel, and the end of the second leaky transmission line 51 is set to a distance Δ with respect to the end of the first leaky transmission line 4. It is shortened.
That is, the end of the second leaky transmission line 51 is arranged with a difference of the distance Δ with respect to the end of the first leaky transmission line 4.
This distance Δ is set by Δ = (2n−1) × λg / 4 (where n is a natural number and λg is a wavelength in the leaky transmission line). That is, this indicates that the distance Δ should be an odd multiple of λg / 4.

  Thus, the first and second leakages are reduced by shortening the distance Δ of the termination of the second leakage transmission path 51 by (2n−1) × λg / 4 with respect to the termination of the first leakage transmission path 4. The electric field strength in the vicinity due to the radio waves leaking from the transmission lines 4 and 51 fluctuates with a period λg / 2, and the distribution positions of the electric fields due to the radio waves are shifted by λg / 4. That is, the electric field strength of the first leaky transmission line 4 and the electric field strength of the second leaky transmission line 51 vary so as to complement the low electric field strength of each other.

Therefore, also in this embodiment, the wireless tag reader 10 is arranged on the bookshelf 1 by using the first leaky transmission line 4 and the second leaky transmission line 51 as antennas alternately switched by the switch 8. Recorded data can be read from the wireless tags 3 of all books 2, and communication with the wireless tags 3 of all books 2 can be performed efficiently. That is, the wireless tag reader 10 can read the recorded data of the wireless tag with almost no work burden on the operator.
In addition, although what described the thing which open | released the terminal part of the 1st, 2nd leaky transmission lines 4 and 51 was described here, the terminal part of the 1st and 2nd leaky transmission lines 4 and 51 was short-circuited. Also good.

(Third embodiment)
The same reference numerals are given to the same portions as those of the above-described embodiment, and detailed description thereof is omitted.
As shown in FIG. 5, a third leaky transmission line 12 composed of balanced two lines is arranged along the longitudinal direction on the surface of the shelf board forming each shelf of the book shelf 1.

  The third leakage transmission line 12 is connected to the RFID tag reader 10 having one end attached to one side of the bookcase 1 via a cable 13 such as a coaxial cable, and the other end is attached to the other side of the bookcase 1. The switch 8 is connected via a cable 14 such as a coaxial cable. The switch 8 is connected to the second leaky transmission line 52 made of balanced two wires, as well as the first leaky transmission line 42 made of balanced two wires.

As shown in FIG. 6, the first and second leaky transmission lines 42 and 52 are arranged in parallel with the end portions being opened and the start ends being aligned and parallel to the ends of the first leaky transmission lines 42. The terminal of the second leaky transmission line 52 is shortened by a distance Δ.
That is, the end of the second leaky transmission line 52 is arranged with a difference of the distance Δ with respect to the end of the first leaky transmission line 42.
The distance Δ at this time is set by Δ = (2n−1) × λg / 4 (where n is a natural number and λg is a wavelength in the leaky transmission line).

  In this way, the switch 8 is controlled to be switched by shortening the distance Δ of the end of the second leaky transmission line 52 by (2n−1) × λg / 4 with respect to the end of the first leaky transmission line 42. When the first leaky transmission path 42 is connected to the third leaky transmission path 12, and when the second leaky transmission path 52 is connected to the third leaky transmission path 12, the third leaky transmission path The electric field strength in the vicinity due to radio waves leaking from 12 fluctuates with a period of λg / 2, and the distribution positions of the electric fields due to the radio waves are shifted by λg / 4. That is, it fluctuates so as to complement a portion having a low electric field strength.

  Therefore, the wireless tag reader 10 connects the first leaky transmission path 42 and the second leaky transmission path 52 to the third leaky transmission path 12 alternately by the switch 8 so that the wireless tag reader 10 can connect the third leaky transmission path 12. Recording data can be read from the wireless tags 3 of all books 2 that are used as antennas and arranged on the bookshelf 1, and communication with the wireless tags 3 of all books 2 can be performed efficiently. That is, the wireless tag reader 10 can read the recorded data of the wireless tag with almost no work burden on the operator.

In addition, the leakage transmission path arranged on the surface of each shelf board of the bookcase 1 is only the third leakage transmission path 12, and the longitudinal direction between the leakage transmission paths is longer than that in which two leakage transmission paths are arranged. Positioning adjustment and parallelism adjustment are not required. That is, when the first leaky transmission line 42 is connected to the third leaky transmission line 12, and when the second leaky transmission line 52 is connected to the third leaky transmission line 12, the third leaky transmission line is used. The distribution position of the electric field in the vicinity due to the radio wave leaking from the path 12 can be surely shifted by λg / 4. Thereby, it is possible to more reliably complement a portion having a low electric field strength.
In this example, the terminal portions of the first and second leaky transmission lines 42 and 52 are opened, but the terminal portions of the first and second leaky transmission lines 42 and 52 are short-circuited. Also good.

(Fourth embodiment)
In this embodiment, a modification of the second leaky transmission line in the first embodiment described above will be described. Other configurations are the same as those of the first embodiment.
As shown in FIG. 7, a second leaky transmission line 53 in which the end portion of the balanced two wires is short-circuited by the short-circuit member 11 as the second leaky transmission line and the length is shorter than that of the first leaky transmission line 4. Is used.

That is, the start ends of the first and second leaky transmission lines 4 and 53 are aligned and arranged in parallel, and the end of the second leaky transmission line 53 is set at a distance Δ with respect to the end of the first leaky transmission line 4. It is shortened.
That is, the end of the second leaky transmission path 53 is arranged with a difference of the distance Δ with respect to the end of the first leaky transmission path 4.
The distance Δ at this time is set to Δ = n × λg / 2 (where n is a natural number and λg is a wavelength in the leaky transmission line). That is, this indicates that the distance Δ may be an integer multiple of λg / 2.

  In this way, the distance Δ of the end of the second leaky transmission line 53 whose end is short-circuited is shortened by n × λg / 2 with respect to the end of the first leaky transmission line 4. λg / 2 is a fluctuation period of the electric field strength in the vicinity of the first and second leaky transmission lines 4 and 53. Therefore, even if the end of the second leaky transmission line 53 is shortened by n × λg / 2 with respect to the end of the first leaky transmission line 4, the position of the fluctuation period of the electric field strength in the second leaky transmission line 53 is It does not change.

  Therefore, the deviation of the distribution position of the electric field in the vicinity due to the radio waves leaking from the first and second leaky transmission lines 4 and 53 is the same as when the ends of the first and second leaky transmission lines 4 and 53 are aligned. / 4. That is, the electric field strength of the first leaky transmission line 4 and the electric field strength of the second leaky transmission line 53 vary so as to complement the low electric field strength of each other.

  Therefore, also in this embodiment, the wireless tag reader 10 is arranged on the bookshelf 1 by using the first leaky transmission line 4 and the second leaky transmission line 53 as antennas alternately switched by the switch 8. Recorded data can be read from the wireless tags 3 of all books 2, and communication with the wireless tags 3 of all books 2 can be performed efficiently. That is, the wireless tag reader 10 can read the recorded data of the wireless tag with almost no work burden on the operator.

(Fifth embodiment)
This embodiment describes a modification of the second leaky transmission line in the third embodiment described above. Other configurations are the same as those of the third embodiment.
As shown in FIG. 8, the second leaky transmission line is a second leaky transmission line in which the end portion of the balanced two wires is short-circuited by the short-circuit member 11 and the length is shorter than the first leaky transmission line 42 by the distance Δ. A transmission line 54 is used.

That is, the start ends of the first and second leaky transmission lines 42 and 54 are arranged in parallel, and the end of the second leaky transmission line 54 is set to Δ = It is shortened by n × λg / 2 (where n is a natural number and λg is a wavelength within the leaky transmission line).
That is, the end of the second leaky transmission line 54 is arranged with a difference of the distance Δ with respect to the end of the first leaky transmission line 42.
That is, this indicates that the distance Δ may be an integer multiple of λg / 2.

  In this way, the distance Δ between the end of the second leaky transmission line 54 whose end is short-circuited is shortened by n × λg / 2 with respect to the end of the first leaky transmission line 42. λg / 2 corresponds to the fluctuation period of the electric field strength in the vicinity by the first and second leaky transmission lines 42 and 54. Therefore, even if the end of the second leaky transmission line 54 is shortened by n × λg / 2 with respect to the end of the first leaky transmission line 42, the distribution position of the electric field by the first leaky transmission line 42 and the second The deviation from the distribution position of the electric field due to the leaky transmission line 53 is the same as when the end of the first leaky transmission line 42 and the end of the second leaky transmission line 54 are aligned, and remains at λg / 4.

  Therefore, when the switching device 8 is switched and the first leaky transmission line 42 is connected to the third leaky transmission line 12, and when the second leaky transmission line 54 is connected to the third leaky transmission line 12. Thus, the electric field strength in the vicinity due to the radio wave leaking from the third leaky transmission path 12 fluctuates with a period λg / 2, and the distribution positions of the electric fields are shifted by λg / 4. That is, it fluctuates so as to complement a portion having a low electric field strength.

Therefore, the wireless tag reader 10 connects the first leaky transmission path 42 and the second leaky transmission path 54 to the third leaky transmission path 12 alternately by the switch 8 so that the wireless tag reader 10 can connect the third leaky transmission path 12 to the third leaky transmission path 12. Recording data can be read from the wireless tags 3 of all books 2 that are used as antennas and arranged on the bookshelf 1, and communication with the wireless tags 3 of all books 2 can be performed efficiently.
That is, the wireless tag reader 10 can read the recorded data of the wireless tag with almost no work burden on the operator.

  Moreover, only the third leaky transmission path 12 is disposed on the surface of each shelf board of the bookcase 1, and the longitudinal positioning between the leaky transmission paths is the same as in the third embodiment described above. Adjustment and adjustment of parallelism become unnecessary, and the distribution position of the electric field in the vicinity due to the radio wave leaking from the third leaky transmission line 12 can be surely shifted by λg / 4 by the switching operation of the switch 8, and the electric field strength The lower part can be complemented more reliably.

(Sixth embodiment)
The same parts as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
As shown in FIG. 9, only the first leaky transmission line 4 composed of parallel two wires is used, and one end of the first leaky transmission line 4 is connected to the wireless tag reader 10 via a cable 15 such as a coaxial cable. Connected.

  In the first leaky transmission line 4, a diode 16 is connected to a terminal portion as switching means for switching the terminal between open and short. Only one first leakage transmission path 4 is arranged along the longitudinal direction on the surface of the shelf board forming each shelf of the book shelf.

  In such a configuration, when the DC current does not flow from the RFID tag reader 10 through the first leakage transmission path 4 to the diode 16, the two conductors constituting the parallel two wires are not energized, so that the terminal portion is open. become. Further, when a direct current flows from the RFID tag reading device 10 to the diode 16 via the first leakage transmission path 4 and the stray capacitance, the two conductors constituting the parallel two lines are energized, so that the terminal portion is short-circuited. .

  Accordingly, when the terminal portion of the first leaky transmission line 4 is short-circuited when the terminal portion of the first leaky transmission line 4 is open and the electric field intensity in the vicinity due to the radio wave leaking from the leaky transmission line 4 is open. In addition, the electric field strength in the vicinity due to radio waves leaking from the leaky transmission path 4 fluctuates with a period λg / 2, and the distribution positions of the electric fields are shifted by λg / 4. That is, the low electric field strength portions are complemented.

  In this way, the wireless tag reader 10 opens the terminal portion of the first leaky transmission line 4 and controls the short leak to use the first leaky transmission line 4 as an antenna and arranges it on the bookshelf 1. Recording data can be read from the wireless tags 3 of all the books 2 and communication with the wireless tags 3 of all the books 2 can be performed efficiently. That is, the wireless tag reader 10 can read the recorded data of the wireless tag with almost no work burden on the operator.

  In addition, the leakage transmission path disposed on the surface of each shelf of the bookcase is only the first leakage transmission path 4, and the longitudinal positioning adjustment between the leakage transmission paths is the same as in the third embodiment described above. It is not necessary to adjust the parallelism, and the distribution position of the electric field in the vicinity due to the radio wave leaking from the first leaky transmission line 4 can be shifted by λg / 4 reliably by opening and shorting the terminal, and the portion with low electric field strength Can be more reliably complemented.

In this embodiment, the diode is used as the switching means for switching the end of the leaky transmission line between open and short. However, the present invention is not limited to this, and a switch element such as a mechanical switch or a semiconductor switch is used. Then, switching may be performed.
In addition, although each embodiment mentioned above used the book as an article | item, the radio | wireless tag stuck on the book accommodated in the bookshelf which is an article | item storage device was made into the object of radio | wireless communication, it is not necessarily limited to this, A product such as a CD, food, or beverage may be used as an article, and a product displayed on a merchandise display shelf may be a target of wireless communication.

The perspective view which shows the whole structure which concerns on the 1st Embodiment of this invention. The front view which shows the whole structure concerning the embodiment. The block diagram which shows the structure of the antenna device for near field communication based on the embodiment. The block diagram which shows the structure of the antenna apparatus for near field communication which concerns on the 2nd Embodiment of this invention. The front view which shows the whole structure which concerns on the 3rd Embodiment of this invention. The block diagram which shows the structure of the antenna device for near field communication based on the embodiment. The block diagram which shows the structure of the antenna apparatus for near field communication which concerns on the 4th Embodiment of this invention. The block diagram which shows the structure of the antenna apparatus for near field communication based on the 5th Embodiment of this invention. The block diagram which shows the structure of the antenna apparatus for near field communication based on the 6th Embodiment of this invention.

Explanation of symbols

4 1st leaky transmission line 5 2nd leaky transmission line 8 Switching device.

Claims (10)

A first leaky transmission line;
A second leaky transmission path configured such that a distribution position of an electric field due to leaked radio waves is shifted from the first leaky transmission path by λg / 4 (where λg is a wavelength in the transmission line);
Switching means for switching and connecting the first leaky transmission line and the second leaky transmission line to a wireless communication device;
The near field communication antenna device, wherein the wireless communication device performs wireless communication by switching between the first leakage transmission path and the second leakage transmission path. A first leaky transmission line having an open end portion;
A second leaky transmission line whose end portion is short-circuited;
A switch for switching and connecting the first leaky transmission line and the second leaky transmission line to a wireless communication device;
The first leaky transmission line and the second leaky transmission line are arranged in parallel with their ends aligned,
The near field communication antenna device, wherein the wireless communication device performs wireless communication by switching between the first leakage transmission path and the second leakage transmission path. A first leaky transmission line having an open end portion;
A second leaky transmission line with an open end,
A switch for switching and connecting the first leaky transmission line and the second leaky transmission line to a wireless communication device;
The first leaky transmission line and the second leaky transmission line are arranged in parallel,
The difference between the end of the first leaky transmission line and the end of the second leaky transmission line is set by (2n−1) × λg / 4 (where n is a natural number and λg is the wavelength in the transmission line). Arranged,
The near field communication antenna device, wherein the wireless communication device performs wireless communication by switching between the first leakage transmission path and the second leakage transmission path. Between the wireless communication device and the switch, a third leaky transmission line having one end connected to the wireless communication device and the other end connected to the switch is disposed,
4. The near field communication according to claim 3, wherein the wireless communication device performs wireless communication by switching between the first leaky transmission path and the second leaky transmission path and connecting to the third leaky transmission path. Antenna device.   5. The near field communication antenna device according to claim 3, wherein ends of the first leaky transmission line and the second leaky transmission line are short-circuited instead of being opened. 6. A first leaky transmission line having an open end portion;
A second leaky transmission line whose end portion is short-circuited;
A switch for switching and connecting the first leaky transmission line and the second leaky transmission line to a wireless communication device;
The first leaky transmission line and the second leaky transmission line are arranged in parallel,
The terminal of the second leaky transmission line is arranged with a difference set by n × λg / 2 (where n is a natural number and λg is the wavelength in the transmission line) with respect to the terminal of the first leaky transmission line. And
The near field communication antenna device, wherein the wireless communication device performs wireless communication by switching between the first leakage transmission path and the second leakage transmission path. Between the wireless communication device and the switch, a third leaky transmission line having one end connected to the wireless communication device and the other end connected to the switch is disposed,
The near field communication according to claim 6, wherein the wireless communication apparatus performs wireless communication by switching between the first leaky transmission path and the second leaky transmission path and connecting to the third leaky transmission path. Antenna device. A leaky transmission line connected to the wireless communication device;
Switching means for switching the end of this leaky transmission line between open and short circuit,
The near field communication antenna device, wherein the wireless communication device performs wireless communication by switching a terminal of the leaky transmission line between open and short.   9. The near-field communication antenna device according to claim 8, wherein the switching means comprises a diode, and a direct current is passed through the diode to short-circuit the end of the leaky transmission line. The leakage transmission path according to claim 1 is disposed in the article storage unit,
An article storage device comprising the near-field communication antenna device according to claim 1 that performs wireless communication with a wireless tag of an article stored in an article storage unit.

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