JP2009273012A - Portable rfid reader/writer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately control gain and directivity without increasing costs and upsizing a casing. <P>SOLUTION: In a portable RFID reader/writer 1, a conductive element 30 for forming a loop antenna is configured detachably to an element 21 of a dipole antenna 20, the conductive element 30 forming the loop antenna together with a part of the element 21 of the dipole antenna 20. By fitting the conductive element 30 to the element 21 of the dipole antenna 20, the loop antenna can be formed with the conductive element 30 and the part of the element 21 in the dipole antenna 20, thus appropriately controlling gain and directivity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a portable RFID reader / writer provided with a dipole antenna that transmits and receives radio waves to and from an RF tag.

In portable RFID reader / writers, for the purpose of controlling gain and directivity, a configuration is provided in which an antenna can be attached and detached and the angle and length of the antenna can be changed according to the application (for example, patents). References 1 and 2).
Japanese Patent No. 3637821 JP 2005-78100 A

  However, in the configuration in which another antenna is attached to the built-in antenna, there is a problem that the shape of the other antenna is increased, and in the configuration in which the antenna is movable, it is necessary to provide a mechanism for moving the antenna. is there. As a result, there arises a problem that the cost increases and the housing size increases.

  The present invention has been made in view of the above circumstances, and an object thereof is a portable RFID capable of appropriately controlling gain and directivity without incurring an increase in cost and an increase in the size of a housing. It is to provide a reader / writer.

  According to the first aspect of the present invention, the element of the dipole antenna that transmits and receives radio waves to and from the RF tag is provided with a conductor element that forms a loop antenna together with a part of the element of the dipole antenna. Since the detachable attachment part is provided in two places across the conductor, the loop antenna can be formed by the conductor element and a part of the element of the dipole antenna by attaching (attaching) the conductor element to the element of the dipole antenna. And gain and directivity can be appropriately controlled.

  That is, the dipole antenna is linearly polarized and has an absolute gain of about 2.15 [dBi] at the maximum. In free space, the gain has a characteristic of drawing a figure 8 over the entire circumference in the direction perpendicular to the axis of the element. It is difficult to give a strong directivity in a desired direction (RF tag reading / writing direction) in which radio waves are to be transmitted and received. On the other hand, by attaching the conductor element to the element of the dipole antenna, it acts in the same way as the loop antenna, so the gain in the direction orthogonal to the plane on which the loop is formed can be increased, and the direction is strong ( Sharp) directivity can be given.

  Therefore, by attaching the conductor element to the element of the dipole antenna so that the plane of the loop is formed in a direction orthogonal to the desired direction for transmitting / receiving radio waves, the gain in the desired direction for transmitting / receiving radio waves is increased. Therefore, strong directivity can be provided in a desired direction in which radio waves are to be transmitted and received. In this case, as described above, in order to increase the gain in a desired direction in which radio waves are to be transmitted / received, it is only necessary to attach the conductor element to the element of the dipole antenna. There is no need to provide a mechanism for moving the battery, and it is possible to avoid an increase in cost and a decrease in the size of the housing.

  In addition, by performing a simple operation of attaching / detaching the conductor element to / from the element of the dipole antenna, it is possible to realize the optimum directivity according to the usage form. That is, only in the case where it is necessary to use a dipole antenna alone without attaching a conductor element to the element of the dipole antenna in a normal use form and to have strong directivity in a desired direction which is a radio wave transmission / reception direction. By attaching the conductor element to the element of the dipole antenna and using the dipole antenna as a loop antenna together with the conductor element, the characteristics of the antenna can be freely selected according to the usage form.

  According to the second aspect of the present invention, the conductor element has a connection portion that can be attached to and detached from the element attachment / detachment portion of the dipole antenna, and the connection portion of the conductor element is attached to the attachment / detachment portion of the element of the dipole antenna. The shape of the dipole antenna element is a predetermined distance away from the dipole antenna element and parallel to the dipole antenna element when viewed in the axial direction. Therefore, the polarization direction of the radio wave radiated from the side facing the element of the dipole antenna can be made the same.

  According to the invention described in claim 3, the conductor element has a connecting part that can be attached to and detached from the attaching / detaching part of the element of the dipole antenna, and the connecting part of the conductor element is attached to the attaching / detaching part of the element of the dipole antenna. The shape of the dipole antenna element is a predetermined distance away from the dipole antenna element and has a side that is perpendicular to the dipole antenna element when viewed in the axial direction. Therefore, two polarization planes can be formed by orthogonally crossing the polarization direction of the radio wave radiated from the side facing the dipole antenna element, and data can be transmitted / received on either polarization plane. it can.

  According to the invention described in claim 4, the length of the loop antenna constituted by the conductor element and a part of the element of the dipole antenna is one wavelength of the radio wave, and the feeding point and the attaching / detaching portion of the element of the dipole antenna Since the distance between the antenna and the antenna is less than one-eighth of one wavelength of the radio wave, a loop antenna having optimum characteristics can be formed by the conductor element and a part of the element of the dipole antenna.

  According to the invention described in claim 5, since the conductor element is configured to be mounted on the attachment / detachment portion of the element of the dipole antenna so that the conductor element can be rotated about the axis of the element of the dipole antenna as the rotation center, Even when the directivity is changed, it is not necessary to remove (remove) the conductor element attached to the element of the dipole antenna from the element of the dipole antenna. Directivity can be easily changed by rotating to a desired rotational position.

  According to the invention described in claim 6, the optical code reading means for optically reading data from the data reading target is provided, and the direction in which the dipole antenna transmits and receives radio waves to and from the RF tag and the optical code reading means reads the data. The conductor element can be rotated about the axis of the dipole antenna element so that the direction in which the data is optically read from the target is included. Since the dipole antenna transmits and receives radio waves and the optical code reading means optically reads the data, the data reading target having the RF tag and the information code can be used. On the other hand, the position of the portable RFID reader / writer with respect to the data reading target is changed. Without the data can read the data on the optical and from the information code can be read and written to the RF tag.

(First embodiment)
A first embodiment in which the present invention is applied to a portable RFID reader / writer having an information code reading function for optically reading data recorded in an information code (one-dimensional code or two-dimensional code) will be described below with reference to FIG. It will be described with reference to FIG. FIG. 1 shows the overall configuration of a portable RFID reader / writer. The portable RFID reader / writer 1 includes a case 2 made of, for example, a plastic material, which is formed into a bent shape having a generally “H” shape, a head 4 having a reading port 3, and a grip portion 5 that a user grips. Are combined.

  Housed in the housing 2 are a main circuit board 6, a radio circuit board 7, an optical code reading sensor 8 (optical code reading means in the present invention), a battery 9, and the like. The main circuit board 6 is a double-sided mounting board on which various parts can be mounted on both surface parts 6a and 6b, and a liquid crystal display 10 and a key switch part 11 are mounted on one surface part 6a. Various electronic components 12 are mounted on the other surface portion 6b.

  The wireless circuit board 7 is arranged in parallel with the main circuit board 6 described above, and is a double-sided mounting board on which various parts can be mounted on both surface portions 7a and 7b. The electronic component 13 is mounted, and various electronic components 14 are also mounted on the other surface portion 7b. The optical code reading sensor 8 has a function of optically reading data recorded in the information code, and is arranged so that the reading surface 8 a is flush with the opening surface 3 a of the reading port 3.

  In the housing 2, an opening 15 is formed in a rectangular shape on the upper surface 4 a of the head 4, and the transparent panel 16 is opposed to the display surface of the liquid crystal display 10 in the opening 15. Has been placed. An LED display unit 17 is disposed on the upper surface 4 a of the head 4 in the housing 2, and is integrated with the key switch unit 11 on the upper surface 5 a of the grip 5 in the housing 2. Several key tops 18 are arranged. When the user presses the key top portion 18, the pressing force is transmitted to the key switch portion 11, and the key switch portion 11 detects the key pressing operation by the user.

  Push-type trigger switches 19a and 19b for driving the optical code reading sensor 8 described above are arranged on the left and right side surfaces 5b and 5c of the holding unit 5 in the housing 2. In this case, when the user optically reads the data recorded in the information code, the user reads the data on the opening surface 3a of the reading port 3 (the reading surface 8a of the optical code reading sensor 8) while holding the grip portion 5. By pressing the trigger switches 19a and 19b while being addressed to the target information code, the optical code reading sensor 8 can be driven to optically read the data recorded in the information code. It is.

  In the housing 2, a dipole antenna 20 is extended on the head 4 in a direction orthogonal to the longitudinal direction of the housing 2 (directions indicated by “arrows S 1 and S 2” in FIG. 1). The element 21 of the dipole antenna 20 is made of, for example, a copper wire member having a circular longitudinal section, and its length (element length) is a length corresponding to a half wavelength (half wavelength) of radio waves. That is, for example, in a configuration for transmitting and receiving 950 [MHz] UHF band radio waves, one wavelength of the 950 [MHz] UHF band radio waves is about 32 [cm]. [Cm]. The power supply line 22 drawn out from the wireless circuit board 7 is connected to the intermediate portion of the element 21, and the intermediate portion of the element 21 to which the power supply line 22 is connected is a power supply point 23.

  FIG. 2 is a functional block diagram showing the electrical configuration of the portable RFID reader / writer 1 described above. The portable RFID reader / writer 1 has a microcomputer and executes a control program to control the overall operation of the portable RFID reader / writer 1, an RF tag processing unit 25 that transmits and receives radio waves, and the above-described components. An optical code reading sensor 8, an LED display unit 17, a liquid crystal display 10, an external interface (IF) unit 26, a key switch unit 11, a speaker 27, a memory 28, and a power supply unit 28 are provided. Has been.

  The RF tag processing unit 25 transmits a carrier wave modulated by transmission data from the dipole antenna 20, a receiving unit 25b that demodulates the carrier wave received by the dipole antenna 20 and extracts reception data, A signal processing unit 25c that performs signal processing on the transmission data and the reception data is provided. The external interface unit 26 has a wired or wireless connection interface with an external device provided outside the portable RFID reader / writer 1, and transmits / receives various data to / from the external device.

  The speaker 27 receives an output command from the control unit 24 when the control unit 24 normally completes the data transmission / reception operation in the RF tag processing unit 25 and the optical read operation of data in the optical code reading sensor 8, for example. And a notification sound for notifying the user that these operations have been completed normally. The memory 28 stores a control program executed by the control unit 24 and has a storage area capable of storing various work data. The power supply unit 29 generates operating power from the power supplied from the battery 9 and supplies it to each functional block. These functional blocks are constituted by the various electronic components 12 to 14 described above.

  In the present embodiment, a conductor element 30 having a “U” shape is detachably connected to the element 21 of the dipole antenna 20 described above. In this case, an example of the relationship between the element 21 of the dipole antenna 20 and the conductor element 30 is shown in FIG. The length of the conductor element 30 is formed to be equal to or longer than the length corresponding to 3/4 wavelength of the radio wave. The element 21 of the dipole antenna 20 is 1/8 wavelength of the radio wave from the feed point 23 to the feed point 23 as a symmetry center. The two places separated by a distance equal to or less than the distance are the attachment / detachment portions 31 and 32 for attaching / detaching the conductor element 30, and the length of the conductor element 30 and the length between the attachment / detachment portions 31, 32 in the element 21 of the dipole antenna 20. The sum is a length corresponding to one wavelength of radio waves. That is, the configuration in which the conductor element 30 is connected to the element 21 of the dipole antenna 20 is equivalent to a loop antenna that forms a loop length having a length corresponding to one wavelength of the radio wave shown in FIG.

  4 to 6 show a specific configuration in which the above-described conductor element 30 is detachably arranged with respect to the portable RFID reader / writer 1. As shown in FIGS. 4 and 5, the conductive element 30 is formed in a shape in which a conductive linear metal member forms a “U” shape, and two opposing side portions 33 and 34 are formed by side portions 35. It is molded into a connected shape. A horseshoe-shaped connection portion 36 made of an elastically deformable conductive material is provided at the distal end portion of the side portion 33, and a horseshoe-shaped connection made of an elastically deformable conductive material is provided at the distal end portion of the side portion 34. A portion 37 is provided. The length of the side portion 33 (indicated by “B11” in FIGS. 4 and 5), the length of the side portion 34 (indicated by “B12” in FIGS. 4 and 5), and the length of the side portion 35 (in FIG. 4 and the length of a line segment connecting between the connecting portions 36 and 37 (indicated by “A12” in FIGS. 4 and 5) corresponds to a quarter wavelength of the radio wave. It is the length to do. That is, the length of the conductor element 30 is a length corresponding to 3/4 wavelength of the radio wave. When the conductor element 30 is attached to the element 21 of the dipole antenna 20, the conductor element 30 and the element 21 of the dipole antenna 20 A square loop antenna is formed by a part.

  On the other hand, as shown in FIG. 6, the housing 2 has exposed portions 38 and 39 that partially expose the element 21 of the dipole antenna 20 in a part extending from the upper surface 4 a to the front surface 4 b of the head 4. Is formed. A portion of the element 21 of the dipole antenna 20 exposed by the exposed portions 38 and 39 is a portion away from the feeding point 23 by a distance corresponding to 1/8 wavelength of the radio wave. That is, the user positions (opposes) the connection portions 36 and 37 of the conductor element 30 at the portion of the element 21 of the dipole antenna 20 exposed by the exposed portions 38 and 39, and moves toward the inside of the housing 2. By applying a force pushing in the direction to the conductor element 30 and elastically deforming the connection portions 36 and 37, it is possible to connect the conductor element 30 in such a manner that the connection portions 36 and 37 sandwich the element 21 of the dipole antenna 20. is there.

  In this case, the portion between the conductor element 30 and the element 21 of the dipole antenna 20 between the detachable portions 31 and 32 (the portion facing the side portion 35 of the conductor element 30) acts as a loop antenna. In addition, the contact surface that contacts the element 21 of the dipole antenna 20 at the connection portions 36 and 37 of the conductor element 30 has an appropriate frictional force with respect to the element 21, and the conductor element 30 is an element of the dipole antenna 20. 21 is configured to be rotatable in a circumferential direction (indicated by “arrows P1 and P2” in FIG. 6) about the axis of rotation 21.

  Next, the results of simulating the antenna directivity when the conductor element 30 is not attached to the element 21 of the dipole antenna 20 and when the conductor element 30 is attached to the element 21 of the dipole antenna 20 are shown in FIG. Will be described with reference to FIG.

  When the conductor element 30 is not attached to the element 21 of the dipole antenna 20, as shown in FIG. 7A, the dipole antenna 20 is linearly polarized and the absolute gain is about 2.15 [dBi] at the maximum. In the free space, the gain has a characteristic of drawing a figure of 8 over the entire circumference in the direction perpendicular to the axis of the element 21. On the other hand, when the conductor element 30 is attached to the element 21 of the dipole antenna 20, the loop antenna is obtained by attaching the conductor element 30 to the element 21 of the dipole antenna 20, as shown in FIG. And the gain in the plane direction in which the loop is formed (the plane direction formed by including the y-axis and the z-axis in FIG. 7) is reduced, so that the loop is formed. The gain in the orthogonal direction (x-axis direction in FIG. 7) can be made relatively high, and strong (sharp) directivity can be given in that direction.

  In the above-described embodiment, the configuration in which the square loop antenna is formed with the conductor element 30 attached to the element 21 of the dipole antenna 20 has been described. However, the conductor element is attached to the element 21 of the dipole antenna 20. In this state, a rectangular loop antenna may be formed. That is, as shown in FIG. 8, in the conductor element 41, the lengths of the opposing side portions 42 and 43 may be longer than the length of the side portion 44. In this case, the length of the side portion 42 (indicated by “B21” in FIG. 8) and the length of the side portion 43 (indicated by “B22” in FIG. 8) are the length corresponding to 3/8 wavelength of the radio wave. The length of the side portion 44 (indicated by “A21” in FIG. 8) and the length of the line segment connecting the connecting portions 36 and 37 (indicated by “A22” in FIG. 8) are The length corresponds to 1/8 wavelength. In the configuration in which the rectangular loop antenna is formed in this way, the length of the portion of the element 21 of the dipole antenna 20 that forms the loop antenna is shorter than that in the configuration in which the square loop antenna is formed. When the length is equal to or shorter than the length corresponding to 1/8 wavelength, the gain of linearly polarized waves can be maximized.

  The dipole antenna to which the conductor element 30 is attached may have a shape in which the tip side of the element is bent. That is, the dipole antenna housed in the head 2 in the housing 2 has a shape in which the tip end side of the element 52 is bent in the longitudinal direction of the housing 2 as shown in FIG. The antenna 51 may be used, or the dipole antenna 61 having a shape in which the tip side of the element 62 is bent in a direction perpendicular to the longitudinal direction of the housing 2 as shown in FIG. good. In such a configuration in which the dipole antenna in which the tip side of the element is bent is accommodated, the width dimension of the portion that accommodates the dipole antenna in the housing 2 can be shortened, and the housing size can be reduced. Can be planned.

  As described above, according to the first embodiment, by attaching (attaching) the conductor element 30 to the element 21 of the dipole antenna 20 in the portable RFID reader / writer 1, Since the loop antenna is formed with a part of the element 21, the gain in the direction orthogonal to the plane on which the loop is formed can be increased, and strong directivity can be given in that direction. .

  Therefore, by attaching the conductor element 30 to the element 21 of the dipole antenna 20 so that a loop plane is formed in a direction orthogonal to a desired direction for transmitting / receiving radio waves, gain in a desired direction for transmitting / receiving radio waves is achieved. And a high directivity can be provided in a desired direction in which radio waves are to be transmitted and received. In this case, in order to increase the gain in a desired direction in which radio waves are to be transmitted / received, it is only necessary to attach the conductor element 30 to the dipole antenna 20 element 21, so that the shape of another antenna does not increase and the antenna can be moved. It is not necessary to provide a mechanism for making it possible to avoid an increase in cost and a decrease in the size of the housing.

  In addition, since the conductor element 30 is configured to be detachable from the element 21 of the dipole antenna 20, the dipole antenna 20 is used alone without mounting the conductor element 30 in the normal usage form, and the transmission / reception direction of radio waves is obtained. By attaching the conductor element 30 and using the dipole antenna 32 as a loop antenna together with the conductor element 30 only when it is necessary to give a strong directivity in a desired direction, the characteristics of the antenna can be freely adjusted according to the usage form. Can be selected.

  Further, since the conductor element 30 is configured to be rotatable about the axis of the element 21 of the dipole antenna 20, the dipole antenna attached to the element 21 of the dipole antenna 20 can be used even when the directivity is changed. The directivity can be easily changed by rotating the conductor element 30 to a desired rotational position while keeping the conductor element 30 attached to the element 21 of the dipole antenna 20 without having to be detached (removed) from the 20 elements 21. can do.

  Furthermore, the dipole antenna 20 is rotated by rotating the conductor element 30 to a rotational position where the direction in which the dipole antenna 20 transmits and receives radio waves and the direction in which the optical code reading sensor 8 optically reads data from the data reading target are the same. The direction in which radio waves are transmitted and received and the direction in which the optical code reading sensor 8 optically reads data can be matched, and a portable RFID reader / writer for a data reading target having an RF tag and an information code. The data can be read from and written to the RF tag without changing the position of 1 and the data can be optically read from the information code.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, description is abbreviate | omitted about the same part as above-mentioned 1st Embodiment, and a different part is demonstrated. The second embodiment is different from the first embodiment in the shape of the conductor element.

  That is, the conductor element 71 has three side portions 72 to 74 and is formed to have a “Z” shape inclined in a front view, a triangle shape in a plan view, and a triangle shape in a side view. Yes. A horseshoe-shaped connecting portion 75 made of an elastically deformable conductive material is provided at the tip of the side portion 72, and a horseshoe-shaped connection made of an elastically deformable conductive material is provided at the tip of the side portion 73. A portion 76 is provided. The length of the side portion 72 (indicated by “B31” in FIG. 9) and the length of the side portion 73 (indicated by “B32” in FIG. 9) are equal to the length of the three side portions 72 to 74. The sum (the length of the conductor element 71) is a length corresponding to 3/4 wavelength of the radio wave, and the conductor element 71 and the element 21 of the dipole antenna 20 with the conductor element 71 attached to the element 21 of the dipole antenna 20 A three-dimensional loop antenna is formed by a part of the antenna. The conductor element 71 is also rotatable in the circumferential direction about the axis of the element 21 of the dipole antenna 20 as the center of rotation.

In the first embodiment described above, the conductor element 30 is formed into a planar shape,
When the conductor element 30 is mounted on the element 21 of the dipole antenna 20, the side 35 facing the element 21 of the dipole antenna 20 on the element 21 of the dipole antenna 20 is formed on the element 21 of the dipole antenna 20 as viewed in the axial direction of the element 21. Therefore, the polarization direction of the radio wave radiated from the element 21 of the dipole antenna 20 is the same as the polarization direction of the radio wave radiated from the side portion 35 of the conductor element 30. Only the polarization plane is formed.

  On the other hand, in the second embodiment, the conductor element 71 is formed into a three-dimensional shape. When the conductor element 71 is attached to the element 21 of the dipole antenna 20, the conductor element 71 is located in the conductor element 71. The side portion 74 facing the 20 element 21 is perpendicular to the element 21 of the dipole antenna 20 as viewed in the axial direction of the element 21, so the polarization direction of the radio wave radiated from the element 21 of the dipole antenna 20 And the polarization direction of the radio wave radiated from the side portion 74 of the conductor element 71 are orthogonal to each other to form two directions of polarization planes.

  Also in this case, when the conductor element 71 is attached to the element 21 of the dipole antenna 20, the conductor element 71 is attached to the element 21 of the dipole antenna 20 as shown in FIG. Since the gain in the plane direction in which the loop is formed is reduced, the gain in the direction orthogonal to the plane in which the loop is formed can be relatively increased, and the direction has strong directivity. In addition, two polarization planes of horizontal polarization and vertical polarization can be formed, and the range in which radio waves can be transmitted and received can be expanded.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
The present invention can also be applied to a configuration that does not have an optical code reading sensor.
The element of the dipole antenna may be formed in a folded shape.
In the second embodiment, the conductor element may have any other shape as long as the side facing the element of the dipole antenna has a side that is perpendicular to the element of the dipole antenna as viewed in the axial direction of the element. It may be formed in the shape of

The 1st Embodiment of this invention is shown, the top view which shows the whole structure, a front view, and a vertical side view Functional block diagram The figure which shows an example of the relationship between the element of a dipole antenna, and a conductor element A plan view and a side view showing the configuration of the conductor element The perspective view which shows the connection part of a conductor element A plan view, a front view, and a longitudinal side view showing a state in which the conductor element is mounted Diagram showing simulation results 4 equivalent diagram The top view and side view which show the aspect by which the conductor element is connected to the element of the dipole antenna The top view which shows the 2nd Embodiment of this invention, and shows the structure of a conductor element, a front view, and a side view FIG. 9 is a plan view, a front view, a side view, and a perspective view showing a state in which the conductor element is connected to the element of the dipole antenna. 6 equivalent diagram 7 equivalent diagram

Explanation of symbols

  In the drawings, 1 is a portable RFID reader / writer, 8 is an optical code reading sensor (optical code reading means), 20 is a dipole antenna, 21 is an element, 30 is a conductor element, 31 and 32 are detachable parts, and 33 to 35 are sides. , 36 and 37 are connection parts, 41 is a conductor element, 42 to 44 are sides, 51 is a dipole antenna, 52 is an element, 61 is a dipole antenna, 62 is an element, 71 is a conductor element, and 72 to 74 are sides. , 75 and 76 are connecting portions.

Claims (6)

A portable RFID reader / writer provided with a dipole antenna that transmits and receives radio waves to and from an RF tag,
The element of the dipole antenna is provided with a detachable part that can attach and detach a conductor element that forms a loop antenna together with a part of the element of the dipole antenna at two positions sandwiching a feeding point of the element of the dipole antenna. A portable RFID reader / writer. The portable RFID reader / writer according to claim 1,
The conductor element has a detachable connecting portion to the detachable portion of the element of the dipole antenna, and the connecting portion of the conductor element is attached to the detachable portion of the element of the dipole antenna from the element of the dipole antenna. A portable RFID reader / writer, wherein the portable RFID reader / writer is formed into a shape having a side portion that is separated by a predetermined distance and is parallel in an axial direction of the element of the dipole antenna. The portable RFID reader / writer according to claim 1,
The conductor element has a detachable connecting portion to the detachable portion of the element of the dipole antenna, and the connecting portion of the conductor element is attached to the detachable portion of the element of the dipole antenna from the element of the dipole antenna. A portable RFID reader / writer, wherein the portable RFID reader / writer is formed into a shape having a side portion that is separated by a predetermined distance and is vertical in the axial direction of the element of the dipole antenna. The portable RFID reader / writer according to any one of claims 1 to 3,
The length of the loop antenna formed by the conductor element and a part of the element of the dipole antenna is one wavelength of radio wave, and the distance between the feeding point of the element of the dipole antenna and the attaching / detaching portion is A portable RFID reader / writer characterized by being one-eighth or less of one wavelength of radio waves. The portable RFID reader / writer according to any one of claims 1 to 4,
A portable RFID reader / writer characterized in that a connecting portion of the conductor element is attached to an attaching / detaching portion of the element of the dipole antenna so that the conductor element can rotate about the axis of the element of the dipole antenna. The portable RFID reader / writer according to claim 5,
Optical code reading means for optically reading data from a data reading target is provided,
The conductor element includes the rotational position such that the direction in which the dipole antenna transmits and receives radio waves to and from the RF tag and the optical code reading means read the data from the data reading target are the same. A portable RFID reader / writer, wherein a connecting portion of the conductor element is attached to an attaching / detaching portion of the element of the dipole antenna so as to be rotatable about the axis of the element of the dipole antenna.

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