JP6546382B2 - RFID system - Google Patents

Description

  The present invention relates to an antenna device suitable for wireless communication with an RFID tag, and an RFID system that reads information from the RFID tag using the antenna device.

  Conventionally, in order to prevent the product from being stolen in a store etc., an RFID tag is attached to the product, and the reader acquires identification information (ID) from the RFID tag via an antenna device installed at the entrance of the store. Thus, an RFID system is known that can automatically detect a customer who is attempting to take out a product illegally from a store (see, for example, Patent Document 1).

Unexamined-Japanese-Patent No. 2004-295599

  In this type of RFID system, in order to detect an RFID tag passing through a desired area such as a doorway, the antenna apparatus having directivity is used, and the radiation direction of the radio wave from the antenna apparatus is made to correspond to the detection range. There is a need.

  Therefore, when the antenna device is installed or when the detection range is changed due to remodeling etc. in the store, the radiation direction of the radio wave from the antenna device is adjusted, but the antenna device is installed at a high place such as a ceiling Therefore, when adjusting the radiation direction, it is difficult for the user to hold the antenna device by hand and physically change the direction.

  The present invention has been made in view of these problems, and after installation on a ceiling or the like, an antenna device capable of easily adjusting the radiation direction of radio waves by remote control, and an RFID system using the antenna device Intended to be provided.

The antenna device according to claim 1, which has been made to achieve such an object,
A plurality of antenna parts arranged at predetermined intervals so that the radiation directions are the same;
A signal combining unit that combines outputs from the plurality of antenna units;
A phase adjustment unit that adjusts at least one of the outputs from the respective antenna units synthesized by the signal synthesis unit;
By adjusting the phase difference of the output from each of the antenna units synthesized by the signal synthesis unit via the phase adjustment unit according to the command signal input from the outside, the direction of synthesized radiation by the plurality of antenna units Control unit to set
It is characterized by having.

The invention according to claim 2 is the antenna apparatus according to claim 1 in which
The plurality of antenna units are formed of planar antennas, and are housed in the case of the antenna device so that the radiation direction is inclined at the same angle with respect to the installation surface of the antenna device on the installation object It is characterized by

Also, in the antenna device according to the third aspect of the present invention, in the antenna device according to the first aspect,
Each of the plurality of antenna units is configured by a planar antenna formed on a different substrate,
In each case, the planar antennas have the same distance from the installation surface to the installation object of the antenna device in the case of the antenna device, and the radiation direction is inclined at a predetermined angle with respect to the installation surface , It is characterized by being stored.

In the antenna device according to the third aspect of the present invention, in the antenna device according to the third aspect,
The lengths of signal paths from the planar antennas to the signal combining unit are combined by the signal combining unit when the amount of phase adjustment by the phase adjusting unit disposed on the signal path is zero. It is characterized in that the output from each planar antenna is set to be in phase.

The invention according to claim 5 is the antenna device according to any one of claims 2 to 4.
Each of the planar antennas is accommodated in the case via a support portion capable of adjusting an inclination angle with respect to the installation surface.

In the antenna device according to the sixth aspect of the present invention, in the antenna device according to any one of the first to fifth aspects,
A wireless communication unit for performing short distance wireless communication with an external wireless terminal;
The control unit may change the combined radiation direction in accordance with the command signal when the command signal is received by the wireless communication unit.

On the other hand, the RFID system according to claim 7 is
The antenna device according to claim 6,
A reading device for reading information from the RFID by transmitting and receiving radio waves to and from the RFID tag via the antenna device;
An information distribution device for distributing information to portable terminals around the antenna device via a wireless communication unit of the antenna device;
It is characterized by having.

  The antenna apparatus according to claim 1 comprises: a plurality of antenna units arranged at predetermined intervals such that the radiation directions are in the same direction; a signal combining unit combining the outputs from the plurality of antenna units; A phase adjustment unit and a control unit are provided.

  The phase adjustment unit is for adjusting the phase difference of the outputs from the respective antenna units synthesized by the signal synthesis unit by adjusting the phase of at least one of the outputs from the plurality of antenna units. .

  Then, the control unit adjusts the phase difference of the output from each antenna unit synthesized by the signal synthesis unit through the phase adjustment unit according to the command signal input from the outside, thereby synthesizing the plurality of antenna units. Set the radiation direction.

  Therefore, according to the antenna device of the present invention, by transmitting a command signal to the control unit after installation, the radiation direction of the radio wave from the antenna device (the combined radiation direction can be obtained without physically changing the direction of the antenna device. ) Can be adjusted.

  Therefore, when the antenna device of the present invention is used as an antenna device of the above-described RFID system, when the antenna device is installed on a ceiling, or when the detection range of the RFID tag by the antenna device changes after installation, the antenna device It will be possible to easily adjust the radiation direction of radio waves from.

  Here, the plurality of antenna units constituting the antenna device may be any unit capable of transmitting and receiving radio waves to and from the RFID tag, but it is desirable to reduce the weight in consideration of installation work on a ceiling or the like. And for this purpose, it is good to make each antenna part into a plane antenna constituted by forming an antenna pattern in a substrate.

  In addition, as described in Patent Document 1, in the antenna device for an RFID tag, the radiation direction of the radio wave needs to obliquely cross the detection target region through which the RFID tag passes in the vertical direction. For this reason, when the antenna unit is configured by a planar antenna, it is necessary to arrange the opening surface of the planar antenna so as to be inclined with respect to the horizontal plane.

  For this reason, in the antenna device of the present invention, as described in claim 2, a plurality of antenna units are formed by planar antennas, and the radiation directions from the respective planar antennas are to the installation object of the antenna device. It is preferable that the antenna device be housed in the case of the antenna device so as to be inclined at the same angle with respect to the installation surface.

  The reason why the radiation directions from the planar antennas are inclined at the same angle with respect to the installation plane of the antenna apparatus is to make the radiation directions of radio waves from the planar antennas be the same direction. The inclination angles do not have to be exactly the same, and even if they differ by several degrees, there is no practical problem.

  That is, in the present invention, there is no practical problem if the radiation directions of the radio waves from the plurality of antenna units are substantially the same direction, and the antenna units are configured by plane antennas and the radiation directions from the respective plane antennas are installed. In the case of inclining with respect to the surface, the inclining angles may be made substantially the same.

  On the other hand, in the case where a plurality of antenna units are configured as plane antennas in this way, each plane antenna may be formed on the same substrate, but if this is done, the case of accommodating these respective antenna units When the height is increased and the antenna device is installed on the ceiling, the antenna device greatly protrudes from the ceiling.

  That is, when the plurality of antenna units are configured by a plurality of planar antennas formed on the same substrate, and the opening surface of each planar antenna is arranged to be inclined with respect to the horizontal plane, the height direction of the case of the antenna device If the length becomes long and it is installed on an installation object such as a ceiling, the amount of protrusion from the installation object becomes large and the appearance becomes worse.

  Therefore, when a plurality of antenna units are formed by planar antennas, as described in claim 3, each antenna unit is formed by planar antennas formed on different substrates, and each planar antenna is formed. Are stored in the case of the antenna device so that the distance from the installation surface to the installation object of the antenna device is the same and the radiation direction is inclined at a predetermined angle with respect to the installation surface. Good.

  That is, in this case, for example, when the antenna device is fixed to a ceiling, the height from the ceiling of each planar antenna (the planar antenna forming each antenna unit is formed on a common substrate) In other words, the downward length can be shortened.

Therefore, when the antenna device is fixed to the ceiling, the amount of protrusion of the antenna device from the ceiling can be reduced, and the antenna device can be arranged in a good appearance.
When the antenna device is configured in this way, the radiation directions of the radio waves from the respective planar antennas can be matched, but the length of the radiation path along the radiation direction is the deviation of the aperture plane of the two planar antennas. It will be different by the amount of

  Therefore, when the antenna device is configured as described in claim 3, as in claim 4, the length of the signal path from each planar antenna to the signal combining unit is on the signal path. When the amount of phase adjustment by the phase adjustment unit disposed in is zero, it is preferable to set in advance such that the outputs from the planar antennas synthesized by the signal synthesis unit are in phase.

  That is, in this case, the phase adjustment unit does not have to be used for adjusting the length of the signal path generated with the arrangement of each planar antenna, but is used only for adjusting the radiation direction of the radio wave from the antenna device. be able to. For this reason, the phase adjustable range by the phase adjusting unit can be reduced, and the configuration of the phase adjusting unit can be simplified.

  In the antenna device according to any one of claims 2 to 4, as in the fifth aspect, each planar antenna can be adjusted so that the inclination angle with respect to the installation surface on the installation object can be adjusted. It is good to store in the case via the unit.

  In this way, when the antenna device is installed on a ceiling or the like, the radiation direction of the radio wave from the antenna device is roughly adjusted by adjusting the inclination angle of the antenna portion with respect to the case installation surface via the support portion. It is possible to

For this reason, after installation of an antenna device, adjustment work of a radiation direction of an electric wave can be performed more easily, and usability of an antenna device can be improved.
Further, by utilizing the support portion, the radiation direction of the radio wave from the antenna device can be changed beyond the phase adjustable range by the phase adjustment unit, so that the adjustable range of the radiation direction can be wider. It is possible to extend the usable range of the antenna device.

  Next, the control unit only needs to be able to input a command signal for adjusting the radiation direction from the outside, and may be connected by wire to a command device that generates the command signal. However, in this case, at the time of installation of the antenna device, it is necessary to simultaneously perform operations such as installation of the command device and connection of the antenna device and the command device.

  Therefore, as described in claim 6, the antenna device according to the present invention includes a wireless communication unit that performs short distance wireless communication with an external wireless terminal, and the control unit receives an instruction signal from the wireless communication unit. When received, it may be configured to change the synthetic radiation direction in accordance with the command signal.

  That is, in this case, there is no need to perform operations such as installation of the command device and connection of the antenna device and the command device at the time of installation of the antenna device, and the radiation direction can be easily adjusted using the wireless terminal. Will be able to

  On the other hand, the RFID system according to claim 7 comprises not only a reader for reading out information from the RFID by transmitting and receiving radio waves to and from the RFID tag via the antenna device according to claim 6, but also an antenna. An information distribution apparatus is provided that distributes information to portable terminals around the antenna apparatus via a wireless communication unit of the apparatus.

  For this reason, according to the RFID system of the present invention, not only can theft monitoring of a product attached with an RFID tag be performed in a store etc., but also using the wireless communication unit provided in the antenna device Etc. can be distributed to surrounding portable terminals, and the application of the antenna device can be expanded.

It is a perspective view showing the appearance of the antenna device of an embodiment. It is a perspective view showing the internal configuration of the antenna device of an embodiment. It is explanatory drawing showing the radiation direction of the electromagnetic wave from two antenna parts in a case. It is a top view showing the wiring pattern of the circuit board stored in a case. It is a circuit diagram showing the circuit structure of the variable phase shifter mounted in the circuit board of FIG. It is an explanatory view showing directivity characteristics of an antenna device of an embodiment. It is a block diagram showing the composition of the whole RFID system constituted using an antenna device. It is explanatory drawing showing the display screen (a) and direction adjustment procedure (b) of a portable terminal at the time of antenna direction adjustment. It is a circuit diagram showing the other structural example of a variable phase shifter. The support part which made it possible to adjust the radiation direction manually is represented, (a) is a perspective view of the support part which supported the antenna part, (b) is the front view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The antenna device 2 of the present embodiment is installed at an entrance of a store and the like, and used to monitor illegal take-out (theft) of a product, and as shown in FIG. 2, an RDID attached to the product. It has two antenna units 10 and 20 for transmitting and receiving radio waves to and from the tag.

  As shown in FIG. 1 and FIG. 2, the two antenna units 10 and 20 have a disk-shaped base 5 and a lid that is assembled so as to cover the base 5 with one opening end closed. 6 and is housed in a cylindrical case 4.

  Here, the cover 6 of the case 4 is formed of a synthetic resin capable of transmitting radio waves. Further, the base portion 5 is made of synthetic resin or metal, and a plurality of foot portions 8 are provided on the surface (rear surface) opposite to the surface (front surface) on which the lid portion 6 is put. There is.

The foot portion 8 is provided so as to be parallel to the ceiling or wall surface which is the installation object of the antenna device 2 and screwed to the ceiling or wall surface.
As shown in FIG. 2, each of the two antenna units 10 and 20 forms two rectangular conductor patterns on one side of a rectangular double-sided board at intervals along the longitudinal direction of the board, as shown in FIG. It is comprised by making the back surface of a board | substrate into a ground pattern.

And the signal wire penetrated from the back of a double-sided board to a predetermined | prescribed feeding point is connected to two conductor patterns of each antenna part 10 and 20, respectively.
That is, in each of the antenna units 10 and 20, the two conductor patterns respectively constitute two patch antennas 12, 14 and 22 and 24 which are planar antennas.

  Then, as shown in FIG. 3, each of the antenna units 10 and 20 is fixed to the support units 16 and 26 protruding from the front surface of the base unit 5 at both ends in the longitudinal direction of the double-sided board. The substrate surface of the double-sided substrate (in other words, the opening surfaces of the patch antennas 12, 14 and 22, 24) is the plate surface of the base portion 5 of the case 4 (in other words, the installation surface of the installation object of the antenna device 2) ) Is assembled to the base 5 so as to form a predetermined angle α (for example, 45 degrees).

  Further, the heights of the support portions 16 and 26 from the base portion 5 are the same, and the respective antenna portions 10 and 20 are provided with the substrate surface of the double-sided board via the support portions 16 and 26 (in other words, patch antenna 12 And 22 and the opening surfaces of the patch antennas 14 and 24 are parallel to one another.

  For this reason, as shown in FIG. 3, the radiation directions (specifically, the radiation beam central axis) X of the four patch antennas 12, 14, 22, 24 configured by the two antenna units 10, 20 are mutually different. It will be parallel and turn in the same direction.

Next, the circuit board 30 is fixed to the front surface of the base unit 5, and the antenna units 10 and 20 are disposed on the upper side of the circuit substrate 30 opposite to the base unit 5. There is.
The circuit board 30 forms a synthesis circuit by forming a circuit pattern (microstrip line) for synthesizing the reception signals from the respective patch antennas 12, 14, 22, 24 on one side of the double-sided board. There is.

As shown in FIG. 4, the circuit board 30 includes input terminals T12, T14, T22, and T24, and three signal combining units 32, 34, and 36 formed in a circuit pattern.
The input terminals T12, T14, T22, and T24 are for inputting received signals from the patch antennas 12, 14, 22, and 24, respectively.

  Further, the signal combining unit 32 is for combining the received signals from the patch antennas 12 and 14 as the received signal from the antenna unit 10, and the signal combining unit 34 includes the received signal from the antenna unit 20, It is for synthesizing the reception signals from the patch antennas 22 and 24.

  The circuit pattern from the input terminal T12 to the output end of the signal combining unit 32 and the circuit pattern from the input terminal T14 to the output end of the signal combining unit 32 are each for the central axis passing through the output end of the signal combining unit 32. It is formed to be axially symmetrical.

  Similarly, the circuit pattern from the input terminal T22 to the output end of the signal combining unit 34 and the circuit pattern from the input terminal T44 to the output end of the signal combining unit 34 respectively pass through the output end of the signal combining unit 34 It is formed to be axially symmetrical with respect to the axis.

  The signal path 31 extending from the input terminals T12 and T14 to the signal combining unit 32 is set to be longer than the signal path 33 extending from the input terminals T22 and T24 to the signal combining unit 34.

  This is because, as shown in FIG. 3, the propagation paths of radio waves from the X direction received by the patch antennas 12 and 14 are compared with the propagation paths of radio waves from the X direction received by the patch antennas 22 and 24. This is because the length L, which is the positional deviation amount of each of the antenna units 10 and 20 in the X direction, is shortened.

  That is, the respective antenna units 10 and 20 are arranged at the same height position with an interval so that the substrate surface makes a predetermined angle α with the base unit 5. Therefore, when the transmission radio waves from the transmission source in the X direction as viewed from the antenna device 2 are received by each of the antenna units 10 and 20, the length L and the wavelength of the reception signal are added to the reception signal. A determined phase difference will occur.

  Therefore, in the present embodiment, the length of the signal path (wiring pattern) from the input terminals T12 and T14 to the signal combining unit 32 is lengthened by the delay time corresponding to the phase difference, and thereby each signal combining unit 32. , 34 to be in phase.

In FIG. 4, the wiring pattern 35 provided at an interval to the signal path 31 is for forming a capacitance component for transmission impedance adjustment.
The signal paths 37 and 38 from the signal combining units 32 and 34 to the output end of the signal combining unit 36 are formed to be axially symmetrical with respect to the central axis passing through the output end of the signal combining unit 36, Among these, the signal path 37 on the antenna unit 10 side is partially disconnected in the vicinity of the signal combining unit 32.

The variable phase shifter 40 is mounted on the cut portion so that the phase of the reception signal passing through the signal path 37 can be adjusted according to the control voltage (direct current) Vc.
Therefore, the circuit board 30 is provided with a voltage input terminal Tdc for inputting the control voltage Vc, and a voltage input path for transmitting the control voltage Vc inputted to the voltage input terminal Tdc to the variable phase shifter 40. A (wiring pattern) 39 is also provided.

In the present embodiment, the variable phase shifter 40 is configured by a hybrid type variable phase shifter shown in FIG.
That is, the variable phase shifter 40 includes an input terminal 41 connected to the output terminal of the signal combining unit 32, an output terminal 42 connected to the signal path 37, and a voltage input terminal 56 connected to the voltage input path 39. .

  Then, a hybrid circuit configured by the first filters 45 and 46 and the second filters 47 and 48 via the direct current blocking portions 43 and 44 that block direct current signal components at the input terminal 41 and the output terminal 42. It is connected. The direct current shutoff portions 43 and 44 are configured by coupling capacitors and the like.

  The hybrid circuit forms a bridge circuit by the first filters 45 and 46 and the second filters 47 and 48, and one end of each of the first filters 45 and 46 is connected to the input terminal 41 and the output terminal 42. It is connected to the other end of the direct current shutoff portions 43 and 44.

  Further, the second filter 47 is disposed to connect the DC blocking portions 43 and 44 side end portions of the first filters 45 and 46, and the second filter 48 is configured to connect the DC blocking portions 43 of the first filters 45 and 46, It is arranged to connect the opposite end to 44.

  The first filters 45 and 46 are filters matched to the characteristic impedance Z0 of the wiring pattern on the circuit board 30 and matched to the characteristic impedance Z0, and in the present embodiment, a low pass filter (LPF) through which the reception signal can pass. Is configured as.

  The second filters 47 and 48 are filters matched to 1/1/2 impedance of the characteristic impedance Z0 (that is, Z0 / √2), and in the present embodiment, a low pass filter (LPF) through which the received signal can pass. Is configured as.

  Note that the first filters 45 and 46 and the second filters 47 and 48 have the impedances set as described above, and if the received signal can pass, even if it is a high pass filter (HPF), a band pass filter (BPF) may be sufficient.

  In the hybrid circuit configured in this way, the ports 2 and 3 are terminated at the characteristic impedance Z0, with the end opposite to the DC blocking portion 43 or 44 of the first filter 45 or 46 as the port 2 or 3 Then, the reception signal input from the input terminal 41 through the DC blocking unit 43 is divided into two and output from each of the ports 2 and 3, and from the port 4 which is the end on the DC blocking unit 44 side of the first filter 46. The received signal is never output.

On the other hand, when reflecting members are provided at the ports 2 and 3, signals reflected at the ports 2 and 3 appear at the port 4 and are outputted from the output terminal 42 through the DC blocking unit 44.
Therefore, in the present embodiment, low-pass filters (LPFs) 49 and 50 are provided as reflection members at end portions of the first filters 45 and 46 as ports 2 and 3 opposite to the DC blocking portions 43 and 44, By adjusting the filter characteristics, the phase of the received signal output from the output terminal 42 is adjusted.

  That is, the LPFs 49, 50 respectively have coils 51, 52 connected to the ends of the first filters 45, 46 opposite to the DC blocking portions 43, 44, and varicaps 53 for grounding the coils 51 to the ground line. , 54 and.

  Therefore, by adjusting the voltages applied to the varicaps 53 and 54, the LPFs 49 and 50 can change their capacitances to adjust the phase of the reception signal output from the output terminal 42.

  The control voltage Vc input to the voltage input terminal 56 is used as the voltage for phase adjustment, and the variable phase shifter 40 uses DC as an input circuit for applying the control voltage Vc to the LPFs 49 and 50. A direct current filter 57 is provided which passes signal components and blocks unnecessary high frequency signal components.

  The DC filter 57 includes a choke coil 58 provided in series between the voltage input terminal 56 and the end of the first filter 46 opposite to the DC blocking portion 44, the voltage input terminal 56, and the ground line. It is comprised by the capacitor | condenser 59 provided between.

The control voltage Vc input via the DC filter 57 is directly applied to the LPF 50 and is applied to the LPF 49 via the second filter (LPF) 48.
Further, in the LPFs 49 and 50, the characteristics of the coils 51 and 52 and the varicaps 53 and 54 are substantially open when the control voltage Vc is zero, so that the received signal is totally reflected with a phase difference of zero, and the control voltage Vc is Are set so that the received signal is reflected with a phase difference as

  Therefore, in the antenna device 2 of the present embodiment, when the control voltage Vc is zero, the phase difference of the reception signals from the respective antenna units 10 and 20 input to the signal combining unit 36 becomes substantially zero, and the antenna The radiation direction of the radio wave from the device 2 is the X direction which is determined by the mounting angle α of the respective antenna units 10 and 20 to the base unit 5. And, in this case, the radiation characteristic from the antenna device 2 when the antenna device 2 is attached to the ceiling becomes the reference characteristic of the beam center: about 225 degrees, as shown by the solid line in FIG.

  On the other hand, when the control voltage Vc is raised from zero, a phase difference occurs in the reception signals from the respective antenna units 10 and 20 input to the signal combining unit 36, and the radiation characteristic from the antenna unit 10 is generated by the phase difference. However, as shown by a dotted line in FIG. 6, the angle is lower than the reference characteristic.

  That is, when the antenna device 2 of this embodiment is mounted on a ceiling, the radiation characteristic thereof is directed downward by further increasing the inclination of the beam central axis from the reference characteristic in which the beam central axis is inclined by a predetermined angle α from the ceiling The tilt angle can be adjusted by the voltage value of the control voltage Vc, as indicated by a dotted line in FIG.

  Next, since the antenna device 2 of the present embodiment is installed at the entrance of a store or the like to prevent theft of goods and is used to transmit and receive radio waves with the RDID tag attached to the goods. The output terminal Tout of the circuit board 30 is connected to the RFID reader 62 shown in FIG. 7 via a coaxial cable.

  The RFID reader 62 transmits a signal for activating the RFID tag 60 to the monitoring area corresponding to the radiation characteristic via the antenna device 2, and the antenna device receives the signal transmitted from the RFID tag 60 that has received the signal. Receiving via 2 is to detect that the goods have been taken out to the monitoring area.

  In addition, an alarm device 64 is connected to the RFID reader 62, and when the RFID reader 62 detects that the product has been taken out to the monitoring area, it is notified to the store clerk or security guard via the alarm device 64. Inform.

  In addition, since it is necessary to adjust the monitoring area by the antenna device 2 when the antenna device 2 is installed or the shop is remodeled, for example, a plurality of the back sides of the base portion 5 of the antenna device 2 are used. The direction adjusting device 70 shown in FIG. 7 is assembled in the space surrounded by the foot 8.

  The direction adjusting device 70 uses a battery 72 serving as a power supply for driving the internal circuit, a booster circuit 74 for boosting the battery voltage to a predetermined voltage, and a control voltage Vc using the voltage boosted by the booster circuit 74. And a voltage variable circuit 76 for generating

  In addition, the direction adjustment device 70 performs wireless communication with the surrounding portable terminals (smartphones, tablets, etc.) using “Bluetooth (registered trademark)” which is one of the short distance wireless communication methods. A module 78 is provided.

  Then, when the wireless communication module 78 receives a command signal for adjusting the antenna direction from the portable terminal 66 for direction adjustment, the wireless communication module 78 controls the voltage variable circuit 76 according to the set value included in the command signal. The control voltage Vc corresponding to the set value is output.

For this reason, the radiation direction of the radio wave from the antenna device 2 can be arbitrarily set using the portable terminal 66 for direction adjustment which the installer or administrator of the antenna device 2 possesses.
The mobile terminal 66 for direction adjustment is a general mobile terminal (smartphone, tablet, etc.) with an application (program) for direction adjustment installed, and the application is activated to display the mobile terminal 66. By displaying the screen for direction adjustment illustrated in FIG. 8A on the unit, the radiation direction of the radio wave from the antenna device 2 can be adjusted.

  That is, the display screen illustrated in FIG. 8A includes a “connect” button for connecting a communication line with the wireless communication module 78, a “cut off” button for disconnecting the communication line, and radiation to the wireless communication module 78. “Output” button for transmitting the set value of direction, “1” to “6” selection buttons for selecting the set value from among a plurality of preset voltage values, and the control voltage Vc as the set value And a display area 67 for displaying the current setting value of the radiation direction or the setting value changed by the user.

  Then, when the user operates the “connect” button with the touch panel provided in the display unit of the portable terminal 66, the control circuit (microcomputer) in the portable terminal 66 performs the radiation direction setting process shown in FIG. Run.

  In this radiation direction setting process, a connection request is transmitted to the wireless communication module 78 of the antenna device 2 in S110 (S represents a step), and the communication line with the wireless communication module 78 is connected in the subsequent S120. If the communication line is not connected, S110 is executed again to wait for connection (so-called pairing) to the wireless communication module 78.

  When it is determined in S120 that the communication line is connected, the process proceeds to S130, the present setting value in the radiation direction is acquired from the wireless communication module 78, and the acquired setting value is displayed in the display area 67. Do.

  Next, in S140, whether or not the user operates the selection buttons “1” to “6” or inputs the control voltage Vc to the voltage input area 68 to set the radiation direction. To judge.

Then, if there is no setting input, the determination processing of S140 is executed again to wait for the user to make a setting input.
If it is determined in S140 that a setting input has been made, the display of the setting value is updated by displaying the setting value corresponding to the input in the display area 67, and the process returns to S140.

As a result, in the display area 67, the current radiation direction of the antenna device 2 or the setting value indicating the radiation direction changed by the user is displayed.
Also, in this state, when the user operates the “output” button, the setting value displayed in the display area 67 is transmitted to the wireless communication module 78, and when the user operates the “disconnect” button, the wireless communication module Disconnect the communication line with 78.

  Then, the wireless communication module 78 controls the voltage variable circuit 76 in accordance with the set value transmitted from the portable terminal 66 and causes the voltage variable circuit 76 to output the control voltage Vc corresponding to the set value. The person can set the radiation direction of the radio wave from the antenna device 2 via the portable terminal 66 arbitrarily.

Further, in the system shown in FIG. 7, the advertisement delivery server 80 is connected to the wireless communication module 78 via a wired or wireless communication line (for example, a LAN).
The advertisement distribution server 80 uses the wireless communication module 78 to transmit information from the store where the antenna device 2 is installed, event information at facilities around the terminal, and other information around the mobile terminals targeted for advertisement distribution. 79 for delivery.

  The portable terminal 79 targeted for advertisement distribution is a portable terminal on which an application for acquiring the guidance information from the advertisement distribution server 80 is activated, and the wireless communication module 78 executes the application by executing the application. In response to the identification information for connection (pairing) transmitted from the portable terminal 79, the communication line with the portable terminal 79 is connected, and predetermined information is distributed.

  As described above, in the antenna device 2 of the present embodiment, the two antenna units 10 and 20 disposed at predetermined intervals so that the radiation directions are the same direction, and the two antenna units 10 and 20 And a circuit board 30 for synthesizing the output from the circuit.

  Then, on the circuit board 30, a wiring pattern consisting of microstrip lines is formed so that the outputs from the respective antenna units 10 and 20 can be synthesized in phase by the signal synthesis unit 36, and from one antenna unit 10 A variable phase shifter 40 is provided on the wiring pattern leading to the signal combining unit 36.

  Therefore, according to the antenna device 2 of the present embodiment, using the variable phase shifter 40, a phase difference is generated in the output from each of the antenna units 10 and 20 combined by the signal combining unit 36. Thus, it is possible to change the combined radiation direction (that is, the radiation direction of the radio wave from the antenna device 2) by the two antenna units 10 and 20.

  Therefore, according to the antenna device 2 of the present embodiment, when the antenna device 2 is installed on the ceiling, or when the area to be monitored of the RFID tag 60 changes after installation, the radiation direction of the radio wave from the antenna device 2 Can be changed to make the radiation direction correspond to the monitoring area.

  Further, in order to adjust the radiation direction, the antenna device 2 of the present embodiment is provided with a direction adjustment device 70 provided with a wireless communication module 78. For this reason, the radiation direction of the antenna device 2 can be easily set and changed without physically changing the direction of the antenna device 2 by using the mobile terminal 66 for direction adjustment.

  Moreover, in the antenna apparatus 2, although the antenna parts 10 and 20 are comprised with the planar antenna which consists of patch antennas, these each antenna parts 10 and 20 are each comprised using a different board | substrate.

  Further, each of the antenna units 10 and 20 has the same distance from the ceiling as the installation object to the base unit 5 of the antenna device 2, and the radiation direction is inclined at a predetermined angle α with respect to the installation surface It is arranged to do.

  Therefore, as compared with the case where the antenna units 10 and 20 are formed on the same substrate and provided in the base 5 of the case 4 so that the radiation direction is inclined at a predetermined angle α with respect to the installation surface of the installation object The protrusion amount from the installation object (in other words, the height of the case 4) can be reduced. Therefore, the antenna device 2 of the present embodiment can be miniaturized, and the appearance of the antenna device 2 mounted on a ceiling that is an installation object can be improved.

  In the antenna device 2 of the present embodiment, the radiation surface of each of the antenna units 10 and 20 is inclined at a predetermined angle α with respect to the base portion 5 of the case 4 (which is the installation surface of the installation object). Instead, when the amount of phase adjustment by the variable phase shifter 40 is zero, the wiring pattern is formed such that the reception signals from the respective antenna units 10 and 20 are input to the signal synthesis unit 36 in phase.

This is in order to minimize the variable range of the radiation direction to be changed by the amount of phase shift by the variable phase shifter 40 based on the tilt angle α of the antenna units 10 and 20.
That is, when the phase adjustable range by the variable phase shifter 40 is increased, the passing loss of the received signal when passing through the variable phase shifter 40 is also increased, and a desired antenna gain can not be realized.

  Therefore, in the present embodiment, in order to be able to change the radiation direction of the antenna device 2 by suppressing the phase adjustable range in the variable phase shifter 40 to the necessary minimum, it is configured as described above. .

  Further, in the present embodiment, by connecting the advertisement distribution server 80 to the wireless communication module 78 in the direction adjustment device 70 provided in the antenna device 2, the advertisement distribution server 80 can transmit surrounding information via the wireless communication module 78. The predetermined information can be distributed to the portable terminal 79.

  Therefore, according to the present embodiment, not only can theft monitoring of a product attached with an RFID tag be performed in a store or the like, but also the wireless communication module 78 provided in the antenna device 2 can be effectively used. .

In the present embodiment, the variable phase shifter 40 corresponds to the phase adjustment unit of the present invention, and the direction adjustment device corresponds to the control unit of the present invention.
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various aspect can be taken in the range which does not deviate from the summary of this invention.

  For example, in the above embodiment, the variable phase shifter 40, which is the main part of the present invention, has been described as being configured by the hybrid variable phase shifter shown in FIG. 5, but as illustrated in FIG. The variable phase shifter 40 can also be configured as a phase shifter using the λ / 4 strip line 82.

  The variable phase shifter 40 shown in FIG. 9 is a strip serving as a transmission path of a reception signal between the input terminal 41 and the λ / 4 strip line 82 and between the λ / 4 strip line 82 and the output terminal 42. It is configured by connecting at lines 81 and 83 and connecting LC parallel resonant circuits 86 and 87 at both ends of the λ / 4 strip line 82 via high impedance strip lines 84 and 85.

  The LC parallel resonant circuits 86 and 87 are each a well-known circuit configured by connecting a coil and a capacitor in parallel, and one end of the coil and the capacitor is connected to the stripline 84, 85 and the other end is grounded. It is grounded to the line.

  The variable phase shifter 40 shown in FIG. 9 uses the varicaps 88 and 89 as the capacitors of the LC parallel resonant circuits 86 and 87, and adjusts the capacitance with the control voltage Vc, thereby removing the strip lines 81 to 83. The phase of the received signal transmitted from the input terminal 41 to the output terminal 42 can be adjusted via

  For this reason, in the variable phase shifter 40 shown in FIG. 9 as well as the variable phase shifter 40 shown in FIG. As an input circuit of the present invention, a DC filter 57 is provided which passes a DC signal component and cuts off an unnecessary high frequency signal component.

  At the control voltage Vc input to the LC parallel resonance circuits 86 and 87 via the choke coil 58 in the DC filter 57, the coils in the LC parallel resonance circuits 86 and 87, the LC parallel resonance circuit 86, In order to prevent the flow of direct current to the strip lines 84 and 85 connected to 87, a capacitor for blocking direct current is provided.

  Next, in the above embodiment, the support portions 16 and 26 for assembling the antenna portions 10 and 20 to the base portion 5 are provided so as to protrude from the front surface of the base portion 5, and the antenna portion is provided Although 10 and 20 were explained as what is fixed, support parts 16 and 26 may be constituted as shown in FIG.

  That is, the support parts 16 and 26 shown in FIG. 10 are comprised by two members, the fixed member 90 protrudingly provided by the base 5, and the movable member 92 fixed to the antenna part 10. As shown in FIG. The movable member 92 is provided rotatably with respect to the fixed member 90 via the fixed shaft 94. Further, the movable member 92 is formed with an arc-shaped long hole 96 centered on the fixed shaft 94, and a screw 98 screwed into the screw hole of the fixed member 90 is inserted into the long hole 96. ing.

  Therefore, each of the support portions 16 and 26 shown in FIG. 10 can rotate the movable member 92 about the fixed shaft 94 by loosening the tightening of the screw 98, and by tightening the screw 98, the movable member 92 can be rotated. It can be fixed to the fixing member 90 at a predetermined angle.

  Therefore, if the antenna units 10 and 20 are fixed to the base unit 5 using the support units 16 and 26 shown in FIG. 10, the inclination angle α of the antenna units 10 and 20 with respect to the base unit 5 is changed. As a result, the radiation direction (reference direction) of the antenna device 2 when the phase shift amount of the variable phase shifter 40 is zero can be set arbitrarily.

Therefore, after installation of the antenna device 2, adjustment work of the radiation direction of a radio wave can be performed more easily, and usability of the antenna device can be improved.
Next, in the above embodiment, two patch antennas 12, 14 and 22, 24 are provided in the antenna units 10, 20, respectively, and the reception signals from these patch antennas 12, 14 and 22, 24 are in phase. By combining, they are taken in as received signals from the respective antenna units 10 and 20.

This is to increase the gain of the antenna units 10 and 20, and each of the antenna units 10 and 20 may be configured by one antenna element.
Further, in the above embodiment, the antenna device 2 includes the two antenna units 10 and 20, and the variable phase shifter 40 is provided in the signal path 37 from the antenna unit 10, and the phase of the signal flowing through the signal path 37 Although the radiation direction (the combined radiation direction) of the radio wave from the antenna device 2 can be varied by making the adjustment possible, the number of antenna parts provided in the antenna device 2 may be three or more.

  Further, the variable phase shifter may be provided in the signal path from all the antenna units constituting the antenna device 2 or provided in the signal path of a part of the antenna units constituting the antenna device 2 May be

  Further, in the above embodiment, the antenna units 10 and 20 constituting the antenna device 2 have been described as being configured by planar antennas configured using different substrates, but a plurality of antennas constituting the antenna device The unit may be configured by a planar antenna formed on the same substrate.

  Further, the plurality of antenna units need not necessarily be configured as flat antennas, and may be configured as, for example, an antenna provided with a director and / or a reflector (or both) for the radiator. That is, the antenna part should just have directivity.

  DESCRIPTION OF SYMBOLS 2 ... Antenna apparatus, 4 ... Case, 5 ... Base part, 6 ... Lid part, 8 ... Foot part, 10, 20 ... Antenna part, 12, 14, 22, 24 ... Patch antenna, 16 ... Support part, 30 ... Circuit board 31, 33, 33, 37: Signal path, 32, 34, 36: Signal combining portion 35: Wiring pattern 39: Voltage input path 40: Variable phase shifter 43, 44: DC blocking portion 45, 46 ... 1st filter, 47, 48 ... 2nd filter, 49, 50 ... LPF, 53, 54 ... Varicap, 56 ... Voltage input terminal, 57 ... DC filter, 60 ... RFID tag, 62 ... RFID reader, 64: alarm device, 66, 79: portable terminal, 70: direction adjustment device, 72: battery, 74: boost circuit, 76: voltage variable circuit, 78: wireless communication module, 80: advertisement distribution server, 82: λ / 4 Strip ray , 81,83,84,85 ... stripline, 86, 87 ... parallel resonant circuit, 88, 89 ... varicap, 90 ... fixing member, 92 ... movable member.

Claims (3)

A plurality of antenna units arranged at predetermined intervals so that the radiation directions are the same, a signal combining unit combining outputs from the plurality of antenna units, and the respective antenna units combined by the signal combining unit Of the outputs from the respective antenna units that are combined by the signal combining unit via the phase adjustment unit according to the phase adjustment unit that adjusts at least one of the outputs from A control unit configured to set a combined radiation direction by the plurality of antenna units by adjusting a phase difference, and a wireless communication unit configured to perform short distance wireless communication with an external wireless terminal, and the wireless communication unit An antenna device configured to cause the control unit to change the combined radiation direction according to the command signal when the command signal is received;
A reading device for reading information from the RFID tag by transmitting and receiving radio waves to and from the RFID tag via the antenna device;
An information distribution device for distributing information to portable terminals around the antenna device via a wireless communication unit of the antenna device;
An RFID system characterized by comprising:   In the antenna device, each of the plurality of antenna units is formed of a planar antenna formed on a different substrate,
  In each case, the planar antennas have the same distance from the installation surface to the installation object of the antenna device in the case of the antenna device, and the radiation direction is inclined at the same angle with respect to the installation surface , Is housed,
  The lengths of signal paths from the planar antennas to the signal combining unit are combined by the signal combining unit when the amount of phase adjustment by the phase adjusting unit disposed on the signal path is zero. The RFID system according to claim 1, characterized in that the outputs from each planar antenna are set to be in phase.   The RFID system according to claim 2, wherein each of the planar antennas is housed in the case via a support capable of adjusting an inclination angle with respect to the installation surface.