JP7031902B2 - RF tag reader / writer - Google Patents

Description

The present invention relates to an RF tag reader / writer that performs wireless communication with an RF tag, and more particularly to an RF tag reader / writer that performs wireless communication with an RF tag installed in a box of a base station or the like.

Usually, various devices such as a base station control panel, a switchboard, and a rectifier are attached to a gantry provided in a base station, and these devices are housed in a box. Further, an RF tag for storing the identification information of the base station and the device is also attached to the gantry.

When fixing the RF tag reader / writer that performs wireless communication with this RF tag to the frame inside the box, the resonance frequency of the antenna of the RF tag reader / writer shifts, and good wireless communication with the RF tag cannot be performed. There is. Further, when the antenna of the RF tag reader / writer is covered with a case made of synthetic resin, the resonance frequency of the antenna may fluctuate.

Further, since there are variations in the manufacturing of the antenna, it is not possible to manufacture the antenna so that the resonance frequency is within an appropriate frequency band.
For this reason, techniques for adjusting the resonance frequency of the antenna within an appropriate frequency band have been conventionally proposed.

For example, in Patent Document 1 (Japanese Unexamined Patent Publication No. 10-256825), a method of adjusting the resonance frequency of a surface-mounted antenna and impedance matching are performed when impedance mismatch occurs due to the adjustment of the resonance frequency. The method is disclosed.

In the invention described in Patent Document 1, in the surface mount antenna 10, the resonance frequency is adjusted by trimming the radiation electrode 2 or the second ground electrode 5 to form notches 9a, 9b, 9c. do. Further, when the impedance becomes mismatched due to the trimming of the resonance frequency adjustment, the impedance matching is obtained by trimming the feeding electrode 4 or continuously attaching a metal leaf to one end of the feeding electrode 4. be.

Patent Document 2 (Japanese Unexamined Patent Publication No. 2011-77834) discloses an invention of a portable RF tag reader / writer that more easily realizes a configuration in which the resonance frequency can be easily finely adjusted and the yield can be easily improved.

In the invention described in Patent Document 2, the portable RF tag reader / writer 1 includes an antenna 50 that radiates or receives radio waves, and the antenna 50 is a feeding layer 51 that receives power supply via a feeding point. A laminated structure including a ground layer 52 arranged at a predetermined distance from the power feeding layer 51 and a dielectric layer 53 sandwiched between the feeding layer 51 and the ground layer 52. Further, a conductive adjusting member 60 is connected to the ground layer 52, and the adjusting member 60 is arranged so as to extend to the outside of the ground layer 52.

Patent Document 3 (Japanese Unexamined Patent Publication No. 2000-269728) discloses an invention for easily tuning a plate-shaped inverted-F antenna as a planar antenna suitable for use in a relay amplifier for indoor installation. There is.

In the invention described in Patent Document 3, one of the ground conductor plate 1 and the radiation conductor plate 2 is provided with a tuning element 4 (metallic) capable of adjusting the distance h between the ground conductor plate 1 and the opposing conductor plates. Even in the two-resonance type, tuning elements 4A and 4B are provided on the upper and lower radiation conductor plates 2 and the ground conductor plate 21, respectively, and the arrangement positions of the tuning elements 4, 4A and 4B, and the distance h from the opposing conductor plates. The tuning frequency is adjusted and determined according to the magnitude of.

Japanese Unexamined Patent Publication No. 10-256825 Japanese Unexamined Patent Publication No. 2011-77834 Japanese Unexamined Patent Publication No. 2000-269728

However, in the invention of Patent Document 1, in order to adjust the resonance frequency, the electrode is trimmed or a metal foil is attached, and such work is very troublesome and cannot be adjusted accurately.

In the invention of Patent Document 2, since the resonance frequency is changed depending on the degree of extension of the adjusting member extended from the ground layer, the resonance frequency cannot be adjusted accurately.

In Patent Document 3, the tuning frequency is adjusted by providing a tuning element 4 capable of adjusting the distance h between the ground conductor plate 1 and the radiation conductor plate 2 on either the ground conductor plate 1 or the radiation conductor plate 2. It is stated that it can be done.

However, in Patent Document 3, the coaxial feeder is penetrated through the ground conductor plate, and the tip of the coaxial feeder is connected to the radiation conductor plate. Therefore, since the coaxial feeder affects the capacitance between the ground conductor plate 1 and the radiation conductor plate 2, the tuning frequency cannot be adjusted as desired even by the tuning element.

Further, the adjustment when the plate-shaped inverted-F antenna is housed in the case and when the case is mounted on a gantry or the like and the resonance frequency of the antenna fluctuates is not considered.

An object of the present invention is to provide an RF tag reader / writer capable of easily adjusting a resonance frequency and wirelessly communicating with an RF tag.
Another object of the present invention is to provide an RF tag reader / writer capable of easily adjusting the resonance frequency and wirelessly communicating with the RF tag even when the RF tag reader / writer is attached to a base station mount or the like.

(1)
The RF tag reader / writer according to one aspect is an RF tag reader / writer that performs wireless communication with the RF tag, and includes an antenna and a case for storing the antenna, and the antenna is a ground plate fixed to the case. It has a radiation plate arranged on the ground plate with a predetermined gap, and an adjusting member provided on at least one of the radiation plate and the ground plate, which can adjust the resonance frequency of the antenna, and is an RF tag reader / writer. The antenna is electrically coupled to the base when it is mounted on a metal base.

In this case, since the resonance frequency of the antenna can be changed by the adjusting member, the resonance frequency can be adjusted without using a complicated configuration.
Furthermore, when the RF tag reader / writer is attached to a metal base, the antenna is electrically coupled to the base, so that the antenna and the base are connected via a case (insulating layer or dielectric layer). Since the capacitance is coupled, the base also functions as an antenna. Therefore, a wide band frequency characteristic can be realized.

Further, with this configuration, by adjusting the distance (void) between the adjusting member and the ground plate or the radiation plate, the capacitance of the capacitor composed of the adjusting member and the ground plate or the radiation plate can be controlled, so that impedance matching can be performed. It can be easily adjusted.

(2)
In the RF tag reader / writer according to the second aspect of the invention, in the RF tag reader / writer according to the invention of one aspect, it is preferable that the adjusting member is attached to the radiation plate so that the distance between the adjusting member and the ground plate can be adjusted.

In this case, the resonance frequency of the antenna can be adjusted by simply attaching the adjusting member to the radiation plate, so that the configuration of the RF tag reader / writer can be simplified.

(3)
In the RF tag reader / writer according to the third aspect of the invention, in the RF tag reader / writer according to the invention of one aspect, the adjusting member may be attached to the ground plate so that the distance between the adjusting member and the radiation plate can be adjusted.

In this case, the resonance frequency of the antenna can be adjusted by simply attaching the adjusting member to the ground plate, so that the configuration of the RF tag reader / writer can be simplified.

(4)
In the RF tag reader / writer according to the fourth aspect of the invention, in the RF tag reader / writer according to the third aspect, the adjusting member may be an insulator, a dielectric, or a conductor.

In this case, an adjusting member, which is an insulator, a dielectric, or a conductor, is provided on at least one of the radiation plate and the ground plate, and impedance matching is performed by adjusting the distance between the adjusting member and the ground plate or the radiation plate. It can be easily adjusted.

(5)
The RF tag reader / writer according to the fifth invention is the RF tag reader / writer according to the fourth aspect of the invention, in which the adjusting member is a screw member, and the adjusting member is screwed into a screw hole provided in the radiation plate and screwed freely. It may be combined.
In this case, since it is only necessary to configure the adjusting member with a screw member and screw it into the screw hole of the radiation plate, the structure of the RF tag reader / writer can be greatly simplified.

(6)
The RF tag reader / writer according to the sixth invention is the RF tag reader / writer according to the fifth aspect of the invention, in which a dielectric is disposed between the radiation plate and the ground plate, and the distance between the radiation plate and the ground plate is increased. It may be configured to remain constant.
In this case, the dielectric can be expected to increase the capacitive coupling between the radiation plate and the ground plate, so that the antenna can be miniaturized.

(7)
In the RF tag reader / writer according to the sixth invention, the dielectric may be made of a block of expanded styrene in the RF tag reader / writer according to the sixth invention.
In this case, since the relative permittivity of Styrofoam is very low, an increase in the capacitive coupling between the radiation plate and the ground plate can be expected, so that the antenna can be further miniaturized.

(8)
The RF tag reader / writer according to the eighth aspect of the invention may be a plate-shaped inverted-F antenna in the RF tag reader / writer according to the seventh aspect of the invention.

In this case, the resonance frequency of the plate-shaped inverted-F antenna can be easily set. Further, since the resonance circuit enables the plate-shaped inverted-F antenna to receive the radio wave transmitted from the RF tag reader / writer with high sensitivity, the reading performance of the RF tag can be improved.

(9)
The parts management device according to the ninth aspect of the invention is the RF tag reader / writer according to the eighth aspect of the invention, wherein the base is a pedestal provided in the box of the base station, and the RF tag is attached to the pedestal. May be good.

In this case, when the RF tag reader / writer is attached to a metal frame, the antenna is electrically coupled to the base, so that the antenna and the base are connected to each other via a case (insulation layer or dielectric layer). Since capacitive coupling is performed, a wide band frequency characteristic can be realized.

It is a schematic cross-sectional view of the RF tag reader / writer which concerns on 1st Embodiment. It is a schematic plan view of the RF tag reader / writer shown in FIG. 1. It is a schematic sectional view of the RF tag reader / writer which concerns on 2nd Embodiment. It is a schematic plan view of the RF tag reader / writer shown in FIG. It is a schematic diagram which shows the state which the RF tag reader / writer shown in FIG. 1 is attached to the gantry arranged in the box of a base station.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following description, the same parts are designated by the same reference numerals. Further, in the case of the same reference numeral, their names and functions are also the same. Therefore, detailed explanations about them will not be repeated.

(First Embodiment)
Hereinafter, the first embodiment of the RF tag reader / writer according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing an RF tag reader / writer according to the first embodiment, and FIG. 2 is a plan view of the RF tag reader / writer of FIG.

As shown in FIGS. 1 and 2, the RF tag reader / writer 10 mainly includes an antenna 100 and a case 110 for accommodating the antenna 100.

The case 110 can be composed of an upper case 112 and a lower case 114 made of an insulating material such as synthetic resin. The case 110 can be fixed, for example, on a metal base.
The lower case 114 is fixed to the base by a known fixing member 160 such as a screw, a bolt, and a nut, and the upper case 112 is connected to the lower case 114 by a known means such as snap coupling to form a box-shaped case 110. Will be done.
The box-shaped case 110 is made of, for example, a resin product.

(Antenna configuration)
The antenna 100 mainly includes a ground plate 130 fixed to the lower case 114 and a radiation plate 120 arranged on the ground plate 130 with a predetermined gap.

The ground plate 130 can be formed from a plate-shaped metal material. In the present embodiment, as shown in FIG. 2, the ground plate 130 is formed in a rectangular shape with a size larger than that of the radiation plate 120 in a plan view. The radiation plate 120 is fixed on the ground plate 130 through a certain gap.

In the present embodiment, the radiation plate 120 is formed by bending a rectangular metal plate, and radiation is arranged in parallel with the fixing portion 122 fixed to the ground plate 130 and the ground plate 130 via a gap. It has a portion 124 and a connecting portion 126 connecting the fixing portion 122 and the radiating portion 124.

That is, the radiation plate 120 is formed in a substantially crank shape in a side view, in which the fixing portion 122, the connecting portion 126, and the radiation portion 124 are bent at a right angle.
In order to fix the fixing portion 122 of the radiation plate 120 to the gland plate 130, it can be fixed by a known fixing member such as a screw, a bolt and a nut, or soldering.

An adjusting member capable of adjusting the resonance frequency of the antenna 100 is fixed to the radiating portion 124 of the radiating plate 120.

In this embodiment, the adjusting member is composed of a screw member 140 made of an insulating material such as synthetic resin or a dielectric material.
A screw member 140 is attached across the radiation plate 120 and the ground plate 130 so that the distance between the radiation plate 120 and the ground plate 130 can be adjusted, and is screwed or screwed into a screw hole provided in the radiation plate 120 or the ground plate 130. It is screwed back freely.

That is, as shown in FIG. 1, a through hole 121 for passing the screw member 140 is formed in the radiation plate 120, and a screw hole 138 having a screw groove is formed in the gland plate 130. The screw member 140 is inserted into the through hole 121 of the radiation plate 120, and the tip of the screw member 140 is screwed into the screw hole 138 of the gland plate 130.

By turning this screw member 140, the distance between the ground plate 130 and the radiation plate 120 can be adjusted. Thereby, the capacitance generated by the ground plate 130 and the radiation plate 120 can be finely adjusted accurately and surely. Further, since the capacitance can be set accurately and surely, the capacitance can be set to a predetermined value even in an environment where vibration or the like is likely to occur.

In the embodiment shown in FIG. 1, the screw member 140 is screwed from the radiation plate 120 to the gland plate 130, but conversely, the screw member 140 is screwed from the gland plate 130 toward the radiation plate 120. You may try to do it.
In that case, a through hole is formed in the gland plate 130, and a screw hole is formed in the radiation plate 120. In order to turn the screw member 140, a hole for passing the tip of a tool such as a screwdriver is formed in the case 110, and the tip of the screwdriver is inserted into the case 110 from the outside of the case 110 to adjust the screw member 140. May be good.

The shapes of the radiation plate 120 and the ground plate 130 shown in FIG. 1 are examples, and may be other shapes such as a square.
Further, in the embodiment shown in FIG. 1, the adjusting member is provided at the tip end portion of the radiating plate 120 at the center position in the width direction of the radiating plate 120, but the adjusting member is provided on the base side of the radiating plate 120. It may be shifted to one side in the width direction of the radiation plate 120.

Further, the coaxial cable 150 is connected to the fixed portion 122 of the radiation plate 120. The coaxial cable 150 includes a feeder line 152 as a coaxial core wire and a ground wire 154 provided on the outside of the feeder wire 152 via an insulating layer, and the feeder wire 152 is soldered to a radiation portion 124 of the radiation plate 120. The ground wire 154 is connected to the ground plate 130 by solder or the like. The tip of the feeder line 152 is connected to the radiation portion 124 at the upper part of the connection portion 126, and this connection point serves as a feed point.

The position of the antenna 100 is set so that the impedance at the feeding point is within the setting range.
According to this configuration, since the coaxial cable 150 can be led out from the upper surface of the radiation plate 120 to the outside, the coaxial cable 150 does not get in the way when the antenna 100 is attached to the gantry 200 or the like.

(How to use RF Tag Reader / Writer 10)
The RF tag reader / writer 10 can be attached to a metal base as shown in FIG. In such a case, as an example of the base, a base 200 (rack or the like) provided in the box 900 of the base station may be used (FIG. 5).

Normally, equipment such as a base station control panel, a switchboard, and a rectifier is attached to the base station pedestal 200, and an RF tag for storing identification information and the like that can identify the base station and various equipment is attached. ..

When the RF tag reader / writer 10 is attached to the gantry 200, wireless communication can be performed with the RF tag already attached to the gantry 200.
At that time, a desired resonance frequency can be obtained by adjusting the adjusting member of the antenna 100 and adjusting the capacitance generated by the ground plate 130 and the radiation plate 120.

Further, when the RF tag reader / writer 10 is attached to the metal gantry 200, an electrically insulating layer made of a case 110 is formed between the antenna 100 and the gantry 200, so that the antenna 100 and the pedestal can be connected to each other. A capacitance (capacitor) is generated between them, and an inductance of the RF tag 100 and a resonance circuit can be formed.

By adjusting the adjusting member as described above, even if there is a frequency deviation due to dimensional error, mounting error, etc. of each component of the antenna 100 after the antenna 100 is stored in the case 110, it can be corrected. Can be done.

(Second Embodiment)
3 and 4 show an embodiment configured so that the distance between the adjusting member and the ground plate 130 can be adjusted.

In this embodiment, a screw hole 121 is formed in the radiation plate 120, and the adjusting member can be configured by the screw member 140 screwed into the screw hole 121. The tip of the screw member 140 can be brought closer to the gland plate 130 by turning the screw member 140, or the tip of the screw member 140 can be separated from the gland plate 130 by turning the screw member 140 in the opposite direction.

In this way, by turning the screw member 140, the distance h between the tip of the screw member 140 and the ground plate 130 is adjusted, thereby adjusting the capacitance generated by the ground plate 130 and the radiation plate 120. be able to.

Further, it can be configured so that the distance between the adjusting member and the radiation plate 120 can be adjusted.
For example, an adjusting member can be formed by forming a screw hole in the gland plate 130 and screwing the screw member 140 into the screw hole. By adjusting the distance between the screw member 140 and the radiation plate 120 by turning the screw member 140, the capacitance generated by the ground plate 130 and the radiation plate 120 can be adjusted. In this way, a desired resonance frequency can be obtained by adjusting the distance h between the tip of the screw member 140 and the radiation plate 120.

Further, in this embodiment, a spacer 170 is arranged between the ground plate 130 and the radiation plate 120, and the distance between the ground plate 130 and the radiation plate 120 is kept constant by the spacer 170.

The spacer 170 can be made of a dielectric having a low relative permittivity such as Styrofoam, and is formed of blocks such as a rectangular parallelepiped and a cube in this embodiment. The dielectric constant of the spacer 170 can be 1.1 or more and 7 or less, preferably 1.1 or more and 2.0 or less.

As described above, in the present embodiment, since the frequency of the antenna 100 can be easily fine-tuned, the resonance frequency of the frequency characteristic of the antenna 100 can be adjusted to the center frequency of the standard for each base station. Therefore, when the antenna 100 is attached to the base 200 of the base station, the frequency shift generated by the tolerance of the antenna 100 itself can be adjusted to the RF tag attached to the base station.

Next, FIG. 5 is a schematic view showing a state in which the RF tag reader / writer shown in FIG. 1 is attached to a gantry 200 arranged in a box of a base station.
As shown in FIG. 5, various communication devices 910, 920, 930 and wiring (not shown) are arranged in the box 900 of the base station. The RF tag reader / writer 10 is provided on the base of the gantry 200 in the box 900.
By connecting a reader to the coaxial cable 150 of the RF tag reader / writer 10, it is possible to read the information of the RF tags attached to various communication devices 910, 920, 930 at once.

In the present invention, the RF tag reader / writer 10 corresponds to the "RF tag reader / writer", the case 110 corresponds to the "case", the antenna 100 corresponds to the "antenna", and the ground plate 130 corresponds to the "ground plate". The radiation plate 120 corresponds to the "radiation plate", the adjusting member and the screw member 140 correspond to the "adjusting member", and the base and the gantry 200 correspond to the "base".

A preferred embodiment of the invention is as described above, but the invention is not limited thereto. It will be appreciated that various embodiments are made that do not deviate from the spirit and scope of the invention. Further, in the present embodiment, the actions and effects according to the constitution of the present invention are described, but these actions and effects are examples and do not limit the present invention.

10 RF tag reader / writer 100 Antenna 110 Case 120 Ground plate 130 Radiation plate 140 Screw member 150 Coaxial cable 200 Stand

Claims (6)

An RF tag reader / writer that performs wireless communication with RF tags.
With the antenna
Including the case for storing the antenna.
The antenna is
The ground plate fixed to the case and
A radiation plate arranged on the ground plate with a predetermined gap, and
It has an adjusting member provided on at least one of the radiation plate and the ground plate and capable of adjusting the resonance frequency of the antenna.
When the RF tag reader / writer is attached to a metal base, the antenna is electrically coupled to the base.
The radiation plate includes a radiation portion arranged in parallel with the ground plate via a gap, and a connection portion connecting the radiation portion and the ground plate, and the adjusting member comprises the radiation portion and the ground. RF tag reader / writer that adjusts the distance from the board . The RF tag reader / writer according to claim 1 , wherein the antenna is a plate-shaped inverted-F antenna. The RF tag reader / writer according to claim 2, wherein the feeding point is provided at the boundary between the connecting portion and the radiating portion. The RF tag reader / writer according to any one of claims 1 to 3, wherein the adjusting member is an insulator or a dielectric . The claim that the adjusting member is a screw member, the screw member is inserted into a through hole formed in the radiation portion, and the tip of the screw member is screwed into a screw hole formed in the gland plate. The RF tag reader / writer according to any one of 1 to 4. The RF tag reader / writer according to any one of claims 1 to 5 , wherein the base is a pedestal provided in a box of a base station, and the RF tag is attached to the pedestal.

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