JP2011015202A - Rf tag reader/writer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately keep desired communication distance even when size of an antenna is restricted.SOLUTION: The RF tag reader/writer 1 is configured such that dimensions in the longitudinal direction of a ground layer 11 provided on the rear surface side of a dielectric antenna 7 are shorter than dimensions equivalent to a half of wavelength of radiowave to be radiated and caught by the dielectric antenna 7, a conductor wire 13 one end of which is connected to one end in the longitudinal direction of the ground layer 11 and the other end of which is opened is provided, and the sum of the dimensions in the longitudinal direction of the ground layer 11 and the dimensions of the entire length of the conductor wire 13 is equivalent to a half of wavelength of the radiowave to be radiated and caught by the dielectric antenna 7.

Description

  The present invention relates to an RF tag read / write device that reads and writes data from and to an RF tag via radio waves radiated and captured by a dielectric antenna.

  As a configuration in which a dielectric antenna is mounted on a substrate, for example, there are those shown in Patent Documents 1 and 2.

JP 2001-60823 A JP 2005-184615 A

  Data communication using RF tags is characterized in that a long communication distance can be secured. However, in small RF tag read / write devices and handy RF tag read / write devices, the size of the antenna is reduced due to structural limitations. Currently, it is difficult to ensure adequately, the gain cannot be increased, and a desired communication distance cannot be ensured.

  There are two types of antenna systems: linear polarization and rotational polarization. Linear polarization may or may not be established depending on the positional relationship between the antenna and the RF tag. It is unsuitable for a mode in which the relative position with the RF tag such as a tag read / write device varies, and rotational polarization is desired. However, rotationally polarized waves require a current to flow on the antenna surface, and the size of the antenna needs to be increased. For this reason, when the antenna size is small, the gain cannot be increased and a desired communication distance cannot be secured.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to read and write an RF tag that can appropriately secure a desired communication distance even when the size of the antenna is limited. To provide an apparatus.

  According to the first aspect of the present invention, the dimension in the longitudinal direction is shorter than the dimension corresponding to half the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna. The conductor member is provided on the back side of the dielectric antenna so that the antenna element of the dielectric antenna is located on the opposite side of the radiation direction in which radio waves are radiated, and one end is connected to one end in the longitudinal direction of the conductor member. In addition, a conductor wire having an open end at the other end is provided, and the sum of the length in the longitudinal direction of the conductor member and the length of the entire length of the conductor wire is 2 of the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna. The dimensions corresponded to 1 / min.

  Thus, even when the length in the longitudinal direction of the conductor member is restricted to a dimension shorter than the dimension corresponding to half the wavelength of the radio wave, by providing the conductor wire, the conductor member and the conductor Can be made to function as a reflector that reflects the radio waves radiated from the dielectric antenna, and the radio waves radiated directly from the dielectric antenna and radiated from the dielectric antenna are reflected by the conductor member and the conductor wire. Gain can be increased by combining radio waves. As a result, a desired communication distance can be appropriately ensured even when the size of the dielectric antenna is limited due to the limitation of the area of the conductor member.

  According to the invention described in claim 2, one conductor wire is provided so as to have one or more parallel portions parallel to the longitudinal direction of the conductor member and one or more vertical portions perpendicular to the longitudinal direction of the conductor member. Since it comprised in the shape which has the above bending part, the dimension of the longitudinal direction of the conductor member which a conductor wire occupies can be shortened, and the dimension of the longitudinal direction of the whole apparatus can be shortened.

  According to the invention described in claim 3, since the conductor wire is configured in a meander shape having two or more vertical portions perpendicular to the longitudinal direction of the conductor member, the length of the conductor member occupied by the conductor wire is further increased. The length of the entire device can be further shortened.

  According to the invention described in claim 4, since the conductor lines are configured such that the distance between the vertical portions is equal to or greater than the predetermined distance, the conductor wires function appropriately as a reflector by securing an appropriate distance between the vertical portions. Can be made.

  According to the invention described in claim 5, the dielectric antenna is divided into four quarters of the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna from the other end of the conductor member in the longitudinal direction or the other end of the conductor wire. Since the dielectric antenna can be arranged at the center of the reflector, the conductor member and the conductor wire reflect the radio waves radiated from the dielectric antenna. It can function as a board more appropriately.

  According to the sixth aspect of the present invention, the dielectric antenna is mounted on the multilayer substrate having a flat plate shape, and the conductor member is composed of the conductor layer forming one of the many layers in the multilayer substrate. A conductor member that functions as a reflecting plate that reflects radio waves radiated from a body antenna can be realized by using a conductor layer that is one of many layers in a multilayer substrate.

  According to the seventh aspect of the present invention, since the conductor layer is composed of the ground layer or the power supply layer, the conductor member that functions as a reflector for reflecting the radio wave radiated from the dielectric antenna is formed of a plurality of layers in the multilayer substrate. It can be realized by using a ground layer or a power supply layer forming one of the layers.

  According to the eighth aspect of the present invention, the wing conductor member having a size corresponding to one half of the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna is provided. Since the conductor member and the wing conductor member are arranged so that the longitudinal direction and the longitudinal direction of the wing conductor member are orthogonal to each other, in addition to the conductor member functioning as a reflector that reflects radio waves radiated from the dielectric antenna The wing conductor member can also function as a reflecting plate that reflects radio waves radiated from the dielectric antenna, and a desired communication distance can be ensured more appropriately. In addition, since the wing conductor member has a size corresponding to half the wavelength of the radio wave radiated and captured by the dielectric antenna, reading and writing of the RF tag is performed by bringing the axial ratio close to “1 (0 dB)”. Data can be appropriately read from and written to the RF tag regardless of the orientation of the apparatus.

  According to the invention described in claim 9, the wing conductor member is configured to be rotatable between the retracted state and the deployed state, and is configured to extend along the longitudinal direction of the conductor member in the retracted state. Since it is configured to have a size equivalent to half the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna in the direction perpendicular to the longitudinal direction, data is read from and written to the RF tag. If not, the wing conductor member may be rotated to the retracted state, and the wing conductor member may be rotated to the unfolded state only when data is read from or written to the RF tag.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st Embodiment of this invention is shown, The top view and vertical side view of RF tag reading / writing apparatus Plan view and vertical side view of a multilayer substrate on which a dielectric antenna is mounted Functional block diagram Figure showing measurement results 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram 4 equivalent diagram The 2nd Embodiment of this invention is shown, The top view and vertical side view of RF tag reading / writing apparatus 4 equivalent diagram

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 20. FIG. 1A shows a plan view of the RF tag read / write device, and FIG. 1B shows a vertical side view of the RF tag read / write device. An RF tag read / write device (reader / writer) 1 is a handy type that can be gripped by a user, and a housing 2 of the tag 2 is formed in a wide shape and a linear shape that can be gripped by the user. The holding portion 2b is combined. The head portion 2a is provided with a display portion 3 made of, for example, a liquid crystal display, and the grip portion 2b is provided with a key operation portion 4 in which a plurality of keys are arranged. A multilayer substrate 5 as a main substrate is mounted inside the housing 2, and a battery 6 that supplies operating power of the RF tag read / write device 1 to each unit is mounted. A dielectric antenna 7 and an RF tag control unit 8 (RF tag control means in the present invention) are mounted on one surface portion of the multilayer substrate 5. The dielectric antenna 7 is configured by mounting an antenna element 10 made of a metal plate on an upper surface portion of a dielectric 9 having a rectangular parallelepiped shape.

  2A shows a plan view of the multilayer substrate 5 on which the dielectric antenna 7 is mounted, and FIG. 2B shows a vertical side view of the multilayer substrate 5 on which the dielectric antenna 7 is mounted. ing. A flat ground layer 11 (conductor member in the present invention) and a flat power supply layer 12 are stacked opposite to each other inside the multilayer substrate 5. One end portion of the conductor wire 13 is connected to one end portion (upper end portion in FIG. 1) of the ground layer 11 in the longitudinal direction, and the other end portion of the conductor wire 13 is opened.

  In the multilayer substrate 5, the dimension of the ground layer 11 in the longitudinal direction (indicated by “L 1” in FIG. 2) is equivalent to a dimension corresponding to a quarter of the wavelength of the radio wave radiated and captured by the dielectric antenna 7. The sum of the dimension in the longitudinal direction of the ground layer 11 and the dimension in the longitudinal direction of the conductor wire 13 (indicated by “L2” in FIG. 2) of the radio wave radiated and captured by the dielectric antenna 7 The size is equivalent to a dimension corresponding to half the wavelength. The dielectric antenna 7 is mounted on the multilayer substrate 5 at a position corresponding to the upper end side of the ground layer 11, that is, from the other end portion (lower end portion in FIG. 2) of the ground layer 11. It is mounted at a position separated by a dimension corresponding to a quarter of the wavelength of the radio wave radiated and captured.

  FIG. 3 is a functional block diagram showing the electrical configuration of the RF tag read / write device 1 described above. The processing unit 14 includes a CPU 15, a memory 16, and an input / output unit 17, and is configured by connecting the display unit 3, the key operation unit 4, and the RF tag control unit 8 described above. The CPU 15 outputs a data communication command to the RF tag control unit 8 so as to modulate transmission data and radiate a radio wave having a predetermined frequency from the dielectric antenna 7 or a predetermined frequency captured by the dielectric antenna 7. An RF communication process is performed in which the RF tag control unit 8 performs a receiving operation for demodulating radio waves and extracting received data. Further, the CPU 15 outputs a display command to the display unit 3 to perform display processing for displaying various display information on the display unit 3 or according to the user operating the key operation unit 4. When an operation signal is input from 4, an operation reception process for receiving the input operation signal is performed. Various electronic components constituting the processing unit 14 are mounted on the surface of the multilayer substrate 5. The predetermined frequency of the radio wave radiated and captured by the dielectric antenna 7 is, for example, 952 to 954 [MHz].

In the configuration described above, one end portion of the conductor wire 13 is connected to one end portion of the ground layer 11 in the longitudinal direction, and the sum of the longitudinal dimension of the ground layer 11 and the longitudinal dimension of the conductor wire 13 is determined as the dielectric antenna 7. The dielectric antenna 7 is mounted on the multilayer substrate 5 at a position corresponding to the upper end side of the ground layer 11 with a size equivalent to one half of the wavelength of the radio wave radiated and captured by This is based on the following reasons. That is, the inventor considered the ground layer 11 as a metal plate and measured the following (1) and (2) regarding the relationship between the dielectric antenna and the metal plate. The central portion in the longitudinal direction of the ground layer 11 here indicates a range having a certain width.
(1) Change in gain of V polarization (vertical polarization) when the length (dimension in the longitudinal direction) of the metal plate is changed (2) Change the distance from the center of the metal plate to the dielectric antenna Change of V polarization gain

  FIG. 4 shows measurement conditions (a) and measurement results (b) in (1) described above, where the width of the metal plate is “40 mm”, the distance from the back surface of the dielectric antenna to the metal plate is “5 mm”, The change of the gain of the V polarization when the length of the metal plate is changed from “40 to 200 mm” when the distance from the end of the metal plate to the center position of the dielectric antenna is “25 mm” is shown. Yes. As is apparent from this measurement result, it is understood that the gain of the V polarization is the best when the length of the metal plate is “about 145 mm”. The length of this metal plate, “about 145 mm”, is a value close to one-half the wavelength of the radio wave of 952 to 954 [MHz], for example, a predetermined frequency radiated and captured by the dielectric antenna 7.

  FIG. 5 shows the measurement conditions (a) and measurement results (b) in (2) above. The width of the metal plate is “40 mm”, the length of the metal plate is “140 mm”, and from the back of the dielectric antenna. When the distance to the metal plate is “5 mm”, the change in the gain of the V polarization when the distance from the center position of the metal plate to the center position of the dielectric antenna is changed by “−50 to 0 mm” is shown. ing. As is clear from this measurement result, when the distance from the center position of the metal plate to the center position of the dielectric antenna is “0 mm” (the closer the center position of the dielectric antenna is to the center position of the metal plate), V It can be seen that the polarization gain is the best. This is because the dielectric antenna is mounted at the center of the metal plate, so that the metal plate functions most efficiently as a reflector that reflects radio waves radiated from the dielectric antenna, and is directly radiated from the dielectric antenna. This is because the gain is efficiently increased by combining the radio wave and the radio wave radiated from the dielectric antenna and reflected by the metal plate most efficiently.

  Based on the measurement results shown above, in this embodiment, in order to eliminate the size restriction of the dielectric antenna 7 in the handheld RF tag read / write device 1, a conductor wire is formed at one end in the longitudinal direction of the ground layer 11. 13 is connected, and the sum of the dimension in the longitudinal direction of the ground layer 11 and the dimension in the longitudinal direction of the conductor wire 13 corresponds to half the wavelength of the radio wave radiated and captured by the dielectric antenna 7. The dielectric antenna 7 is mounted on the multilayer substrate 5 at a position corresponding to the upper end side of the ground layer 11.

  Next, the inventor examined the shape of the conductor wire connected to the metal plate. First, the inventor measured the relationship between the length of the metal plate and the gain. FIG. 6 shows measurement conditions (a) and measurement results (b). The width of the metal plate is “40 mm”, the distance from the back surface of the dielectric antenna to the metal plate is “5 mm”, and from the end of the metal plate. When the distance to the center position of the dielectric antenna is “70 mm”, the change in the gain of the V polarization when the length of the metal plate is changed is shown. As is apparent from this measurement result, it is understood that the gain of the V polarization is the best when the length of the metal plate is “140 to 160 mm”. In the following, the width of the metal plate is “40 mm”, the length of the metal plate is “90 mm”, the distance from the back surface of the dielectric antenna to the metal plate is “5 mm”, and the center of the dielectric antenna from the end of the metal plate The shape of the conductor wire was examined on the condition that the distance to the position was “70 mm”.

  7 and 8 show changes in the gain of the V polarization when the connection position of the linear conductor wire is changed when the linear conductor wire is connected to the end of the metal plate. 7 (a) and 7 (b) show measurement conditions and measurement results when the connection position of the linear conductor wire is set to the left and right ends, and FIGS. 7 (c) and 7 (d) show the linear conductor wire. 8A and 8B show the measurement conditions and measurement results when the connection positions of the linear conductor wires are at the left and right ends. FIG. 8C shows a comparison of measurement results. As is apparent from this measurement result, the gain is increased in proportion to the length of the conductor wire regardless of the connection position of the straight conductor wire, and the length of the linear conductor wire is “55 mm”. That is, when the sum of the length of the metal plate and the length of the linear conductor wire is “145 mm”, it can be seen that the gain is equivalent to the target value described above, and the linear conductor wire functions as a reflector. You can see that Further, it can be seen that the configuration in which the linear conductor wire is connected to the left and right ends of the metal plate has a slightly higher gain than the other, but the gain is not greatly different regardless of the connection position.

  9 and 10 show the case where the connection position of the L-shaped conductor wire is changed with the entire length of the conductor wire being fixed to “55 mm” when the L-shaped conductor wire is connected to the end of the metal plate. The change of the gain of V polarization is shown. FIGS. 9A and 9B show measurement conditions and measurement results when the connection position of the L-shaped conductor wire is set to the left and right ends. FIGS. 9C and 9D show the L-shaped conductor wire. FIGS. 10A and 10B show the measurement conditions and measurement results when the connection position of the conductor wire is in the center, and FIGS. 10A and 10B show the measurement conditions when the connection position of the L-shaped conductor wire is at the left and right ends. The measurement results are shown, and FIG. 10C shows a comparison of the measurement results. As is apparent from this measurement result, as in the case of connecting the linear conductor wire described above, the length of the L-shaped conductor wire is proportional to the length in the longitudinal direction regardless of the connection position of the L-shaped conductor wire. If the gain is improved and the total length of the L-shaped conductor wire is “55 mm”, that is, if the sum of the length of the metal plate and the total length of the L-shaped conductor wire is “145 mm”, the folding In the range where the bending position exceeds “5 mm” from the end of the metal plate, it can be seen that the gain is equivalent to the above-mentioned target value regardless of the bending position, and the L-shaped conductor wire functions as a reflecting plate. I understand that.

  FIG. 11 shows a comparison of measurement results when a linear conductor wire is connected to the end of the metal plate and when an L-shaped conductor wire is connected to the end of the metal plate. FIG. 11 (a) shows a comparison of measurement results when the connection position of the conductor wire is at one end of the left and right, and FIG. 11 (b) shows a comparison of measurement results when the connection position of the conductor wire is at the center. FIG. 11 (c) shows a comparison of measurement results when the connection positions of the conductor wires are at both the left and right ends. As is apparent from this measurement result, in any case, when connecting the linear conductor wire to the end of the metal plate and connecting the L-shaped conductor wire to the end of the metal plate, In the case of connecting the L-shaped conductor wire, the longitudinal dimension of the conductor member occupied by the conductor wire can be shortened compared to the case of connecting the linear conductor wire, and the longitudinal dimension of the entire device can be reduced. Can be shortened.

  FIG. 12 shows a change in the gain of the V polarization when the L shape is changed. 12 (a) and 12 (b) show measurement conditions and measurements when the L-shape (the length from one end of the conductor wire to the bent portion and the length from the bent portion to the other end) is changed. Results are shown. In any case, the gain is as described above when the length of the conductor wire is “65 mm”, that is, when the sum of the length of the metal plate and the length of the L-shaped conductor wire is “155 mm”. It turns out that it is equivalent to a target value, and it turns out that the L-shaped conductor wire is functioning as a reflecting plate. It can also be seen that the gain is constant around the target value described above when the length from one end of the conductor wire to the bent portion is “35 mm” or more. Note that when the length from one end of the conductor wire to the bent portion is “15 mm” or less, the length from the bent portion to the other end exceeds “40 mm”. It will protrude in the width direction.

  FIG. 13 shows the change in the gain of the V polarization when the meander-shaped conductor wire is connected to the end portion of the metal plate and the length of the conductor wire is changed with the meander-shaped width and interval constant. ing. FIGS. 13A and 13B show measurement conditions and measurement results when the length of the conductor wire is changed when the meander-shaped width is “40 mm” and the interval is “5 mm”. As is apparent from this measurement result, the gain is as described above when the length of the conductor wire is “80 to 90 mm”, that is, when the open end of the conductor wire is “10 mm” from the end of the metal plate. It can be seen that although it is about 0.5 dB lower than the target value, it is substantially equivalent. It can also be seen that the same or better effect can be obtained when the conductor wire is L-shaped.

  FIG. 14 shows a change in the gain of the V polarization when the interval between the meander shapes is changed. FIGS. 14A to 14C show measurement conditions and measurement results when the interval is changed when the meander width is “40 mm”. As is apparent from the measurement results, when the meander-shaped interval is “15 mm”, the gain is maximum when the length of the conductor wire is “60 mm” and exceeds the above-described target value. However, it can be seen that when the meander-shaped interval is reduced, the length of the conductor wire at the maximum gain is increased, and the maximum value of the gain is also decreased. It can also be seen that the maximum gain value converges to “less than 8 dB” as the meander interval increases. It can also be seen that when the meander-shaped interval is reduced, the length of the conductor wire at the time of maximum gain converges to “90 mm”, but the maximum value of gain is lower than “less than 8 dB”, which is meaningless for practical use. It turns out that it is.

  15 to 17 show changes in the gain of the V polarization when the meander shape is arranged in the vertical direction and the width is changed. FIGS. 15A and 15B show measurement conditions and measurement results when the length of the conductor wire is changed when the width of the meander shape is “25 mm” and the interval is “10 mm”. 15 (c) and 15 (d) show measurement conditions and measurement results when the length of the conductor wire is changed when the width of the meander shape is “20 mm” and the interval is “10 mm”. FIGS. 16A and 16B show measurement conditions and measurement results when the length of the conductor wire is changed when the width of the meander shape is “15 mm” and the interval is “10 mm”. c) and (d) show measurement conditions and measurement results when the length of the conductor wire is changed when the meander-shaped width is “10 mm” and the interval is “10 mm”. FIG. Comparison of results is shown. As is apparent from this measurement result, it can be seen that there is no tendency when the width of the meander shape is changed. Also in this case, it can be seen that an effect equal to or greater than that obtained with the L-shaped conductor wire can be obtained.

  FIG. 18 shows a change in the gain of the V polarization when the meander shape is arranged in the vertical direction and the interval is changed. FIGS. 18A to 18C show measurement conditions and measurement results when the length of the conductor wire is changed when the meander width is “20 mm” and the interval is “5 mm” or “10 mm”. ing. As is apparent from this measurement result, it is understood that there is no tendency when the meander shape interval is changed.

  FIG. 19 shows a change in gain when the conductor wire is extended to the back surface of the metal plate. As is apparent from this measurement result, it is understood that the gain is not improved when the dielectric antenna is disposed at a position invisible (overlapping position) from the front direction of the dielectric antenna.

  In order to evaluate the effect of connecting the conductor wire to the metal plate in FIG. 20, when the length of the metal plate is changed, when the L-shaped conductor wire is connected, the meander-shaped conductor wire is connected. The change of the gain of V polarization at the time is shown. As is clear from this measurement result, it can be seen that when the length of the metal plate is changed, the gain decreases as the length of the metal plate decreases. On the other hand, the L-shaped conductor wire or meander shape is reduced. It is understood that the gain does not decrease when the entire length (length in the longitudinal direction from the end of the metal plate to the end of the conductor wire) exceeds “100 mm” when the conductor wires are connected.

In the above description, the conductor wire is connected to only one end of the metal plate. However, the same effect can be obtained with respect to the embodiment in which the conductor wire is connected to both ends of the metal plate.
As described above, according to the first embodiment, in the RF tag read / write device 1, the longitudinal dimension of the ground layer 11 provided on the back surface side of the dielectric antenna 7 is radiated by the dielectric antenna 7. One end is connected to one end in the longitudinal direction of the ground layer 11 and the other end is open when the dimension is shorter than one half the wavelength of the captured radio wave. The conductor wire 13 is provided, and the sum of the dimension in the longitudinal direction of the ground layer 11 and the dimension of the entire length of the conductor wire 13 is a dimension corresponding to half the wavelength of the radio wave radiated and captured by the dielectric antenna 7. Since it is configured, the ground layer 11 and the conductor wire 13 can function as a reflecting plate that reflects the radio wave radiated from the dielectric antenna 7, and the radio wave directly radiated from the dielectric antenna 7 and the dielectric antenna 7 It is possible to increase the gain by causing the synthesis and is emitted is reflected by the ground layer 11 and the conductor line 13 waves. Thereby, even when the size of the dielectric antenna 7 is restricted due to the restriction of the area of the ground layer 11, a desired communication distance can be appropriately ensured.

  Even if the conductor wire 13 is configured in an L shape or a meander shape, an effect equal to or greater than that in the linear shape can be obtained. Therefore, the conductor wire 13 does not necessarily have to be configured in a linear shape, and the conductor pattern 13 is formed in an L shape. By configuring in the shape or meander shape, the longitudinal dimension of the ground layer occupied by the conductor wire 13 can be shortened, and the longitudinal dimension of the entire apparatus can be shortened. Further, the dielectric antenna 7 has a dimension corresponding to a quarter of the wavelength of the radio wave radiated and captured by the dielectric antenna 7 from the other end of the ground layer 11 in the longitudinal direction or the other end of the conductor wire 13. Since the dielectric antenna 7 is disposed at the center of the reflector, the ground layer 11 and the conductor wire 13 are more appropriately used as a reflector that reflects radio waves radiated from the dielectric antenna 7 by disposing the dielectric antenna 7 in the center of the reflector. Can function. Furthermore, the overall length in the longitudinal direction can be further shortened, and the entire apparatus can be reduced in size.

(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. In the second embodiment, a wing antenna unit is added to the first embodiment described above.

  21A and 21B show plan views of the RF tag read / write device, and FIG. 21C shows a longitudinal side view of the RF tag read / write device. The housing 22 of the RF tag read / write device 21 has a head portion 22a and a grip portion 22b having the same width, the head portion 22a is provided with a display portion 23, and the grip portion 22b includes the first portion described above. The key operation unit 4 described in the embodiment is provided. A multilayer substrate 24 as a main substrate is provided inside the housing 22, and the dielectric antenna 7 and the RF tag control unit described in the first embodiment are provided on one surface portion of the multilayer substrate 24. 8 is implemented.

  The multi-layer substrate 24 is formed by laminating a flat plate-shaped ground layer 25 (conductor member in the present invention) and a flat plate-shaped power supply layer in the same manner as the multi-layer substrate 5 described in the first embodiment. In addition, one end portion of the conductor wire 26 is connected to one end portion (upper end portion in FIG. 21) of the ground layer 25 in the longitudinal direction, and the other end portion of the conductor wire 26 is open.

  In the second embodiment, the ground layer 25 is provided with a wing antenna portion 27 (a wing conductor member referred to in the present invention) in a symmetrical manner in a bilaterally symmetrical manner. The wing antenna unit 27 is rotatable between a retracted state in which the wing antenna unit 27 is stored along the longitudinal direction of the housing 22 and an unfolded state in which the tip side protrudes from the housing 22. The dimension (indicated by “L3” in FIG. 21) is a dimension corresponding to half the wavelength of the radio wave radiated and captured by the dielectric antenna 7. This is based on the following reasons. That is, the inventor measured the axial ratio of the shape of the wing antenna part.

  FIG. 22 shows measurement conditions (a) and measurement results (b). The width of the metal plate is “40 mm”, the length of the metal plate is “140 mm”, and the distance from the back surface of the dielectric antenna to the metal plate is as follows. A change in the axial ratio when the shape of the wing antenna portion (the horizontal dimension d and the vertical dimension e) is changed at “5 mm” is shown. As is apparent from this measurement result, it is understood that the axial ratio is the best (the axial ratio is close to “1 (0 dB)”) when the lateral dimension of the wing antenna portion is “about 120 mm”. The horizontal dimension “about 120 mm” of the wing antenna portion is a value close to one-half the wavelength of a radio wave of, for example, 952 to 954 [MHz], which is a predetermined frequency radiated and captured by the dielectric antenna.

  In this case, if the axial ratio deviates significantly from “1”, the RF tag read / write device 21 has a direction in which data can be read / written and a direction in which data cannot be read / written, so the axial ratio becomes “1”. The closer one is desirable. In the present embodiment, the horizontal dimension of the wing antenna unit 27 is set to a value close to one half of the wavelength of the radio wave of 952 to 954 [MHz], which is a predetermined frequency that is radiated and captured by the dielectric antenna 7. Thus, the axial ratio is set to a value close to “1 (0 dB)”, and the user can read and write data without being aware of the direction of the RF tag read / write device 21, thereby improving usability.

  As described above, according to the second embodiment, since the wing antenna unit 27 is provided in the RF tag read / write device 21, the radio waves radiated from the dielectric antenna 7 through the ground layer 25 and the conductor wire 26 are transmitted. In addition to functioning as a reflecting plate that reflects, the wing antenna unit 37 can also function as a reflecting plate that reflects radio waves radiated from the dielectric antenna 7. The gain can be further increased by combining the radio waves radiated from the dielectric antenna 7 and reflected by the ground layer 11, the conductor wire 13, and the wing antenna portion 27. Further, since the size of the wing antenna portion 27 is set to a size corresponding to one half of the wavelength of the radio wave radiated and captured by the dielectric antenna 7, the axial ratio is set to approximately “1 (0 dB)”. Therefore, data can be appropriately read from and written to the RF tag regardless of the orientation of the RF tag read / write device 21, and the usability can be improved.

  Further, since the wing antenna unit 27 is configured to be rotatable between the retracted state and the deployed state, the wing antenna unit 27 is rotated to the retracted state when data is not read from or written to the RF tag, Thus, it is only necessary to rotate the wing antenna portion 27 to the unfolded state only when reading and writing data, and the usability can be improved.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
The RF tag read / write device is not limited to a dedicated device for reading / writing data from / to the RF tag, and may be a portable terminal such as a mobile phone or a portable information terminal incorporating a module for reading / writing data from / to the RF tag. good. In addition, the RF tag read / write device may be fixed and used.

  In the drawings, 1 is an RF tag read / write device, 5 is a multilayer substrate, 7 is a dielectric antenna, 8 is an RF tag control unit (RF tag control means), 9 is a dielectric, 10 is an antenna element, and 11 is a ground layer (conductor). Member), 12 is a power supply layer, 13 is a conductor wire, 21 is an RF tag read / write device, 25 is a ground layer (conductor member), 26 is a conductor wire, and 27 is a wing antenna part (blade conductor member).

Claims (9)

A dielectric antenna in which an antenna element is mounted on the top surface of the dielectric;
RF tag control means for reading and writing data to and from the RF tag via radio waves radiated and captured by the antenna element of the dielectric antenna;
The dielectric antenna is provided on the back side of the dielectric antenna so that the antenna element is located on the opposite side of the radiation direction of radiating radio waves, and the longitudinal dimension is radiated by the antenna element of the dielectric antenna. A conductor member having a dimension shorter than a dimension corresponding to half the wavelength of the radio wave to be captured;
A conductor wire having one end connected to one end in the longitudinal direction of the conductor member and the other end opened;
The sum of the length in the longitudinal direction of the conductor member and the length of the entire length of the conductor wire is configured to correspond to a half of the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna. An RF tag read / write device characterized by that. The RF tag read / write device according to claim 1,
The conductor wire has one or more bent portions so as to have one or more parallel portions parallel to the longitudinal direction of the conductor member and one or more vertical portions perpendicular to the longitudinal direction of the conductor member. An RF tag read / write device having a shape. The RF tag read / write device according to claim 2,
The RF tag read / write device according to claim 1, wherein the conductor wire is formed in a meander shape having two or more vertical portions perpendicular to a longitudinal direction of the conductor member. The RF tag read / write device according to claim 3,
The RF tag read / write device, wherein the conductor wire is configured such that a distance between vertical portions is a predetermined distance or more. The RF tag read / write device according to any one of claims 1 to 4,
The dielectric antenna is equivalent to a quarter of the wavelength of the radio wave radiated and captured by the antenna element of the dielectric antenna from the other end in the longitudinal direction of the conductor member or the other end of the conductor wire. An RF tag read / write device, wherein the device is arranged at a position separated by a dimension to be measured. The RF tag read / write device according to any one of claims 1 to 5,
The dielectric antenna is mounted on a multilayer substrate having a flat plate shape,
The RF tag read / write device according to claim 1, wherein the conductor member is composed of a conductor layer that forms one of a number of layers in the multilayer substrate. The RF tag read / write device according to claim 6,
The RF tag read / write device, wherein the conductor layer is composed of a ground layer or a power supply layer. The RF tag read / write device according to any one of claims 1 to 7,
A wing conductor member configured to have a size corresponding to a half of a wavelength of a radio wave radiated and captured by the antenna element of the dielectric antenna;
The RF tag read / write device, wherein the conductor member and the wing conductor member are arranged so that a longitudinal direction of the conductor member and a longitudinal direction of the wing conductor member are orthogonal to each other. The RF tag read / write device according to claim 8,
The wing conductor member is rotatable between a retracted state and an unfolded state, and is configured to extend along the longitudinal direction of the conductor member in the retracted state, and with respect to the longitudinal direction of the conductor member in the unfolded state The RF tag read / write device is configured to have a size corresponding to a half of the wavelength of a radio wave radiated and captured by the antenna element of the dielectric antenna in a direction perpendicular to the antenna element.

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