JP4305420B2 - Interrogator - Google Patents

Description

  The present invention relates to an interrogator used in a wireless tag detection system that detects a wireless tag that performs wireless communication of information with the outside.

  RFID (Radio Frequency Identification) that reads / writes information of a wireless tag by transmitting and receiving an inquiry and receiving a response from a reader / writer as an interrogator to a small wireless tag as a responder The system is known.

  For example, a wireless tag circuit element included in a label-like wireless tag includes an IC circuit unit that stores predetermined wireless tag information and an antenna that is connected to the IC circuit unit and transmits / receives information. The IC circuit unit demodulates and interprets the signal received by the antenna, modulates and reflects the received carrier wave based on the information signal stored in the memory, and returns it to the interrogator via the antenna.

  At this time, in order to perform demodulation processing in wireless communication as described above with high sensitivity, conventionally, a technique for controlling directivity (particularly, main lobe) by an interrogator antenna has been used. In general, in wireless communication between the interrogator and the RFID circuit element, the communication sensitivity is best when the polarization plane direction of the antenna on the interrogator side and the polarization plane direction of the RFID tag circuit element match. , The communication sensitivity becomes lower as the deviation occurs. Therefore, a method for variably controlling the main lobe and the polarization plane of the interrogator antenna has been proposed (see, for example, Patent Document 1).

In this conventional interrogator, the interrogation signal output from the antenna is reflected by the variable radio wave reflector and transmitted to the wireless tag. At this time, the propagation direction (main lobe) of the interrogated signal is appropriately set by changing the shape or position of the reflecting surface of the variable radio wave reflecting plate by the reflecting plate changing means. In addition, the interrogator antenna has two dipole antennas and phase shifters that are orthogonal to each other, and each dipole antenna has a phase difference of 90 degrees from the phase shifter. Both a response signal transmitted by waves and a response signal transmitted by circularly polarized waves can be received. The variable control of the main lobe and the polarization plane enables reliable communication with the wireless tag regardless of the existence direction and attitude of the wireless tag that is the subject of the interrogator reading (search). It is illustrated.
JP 2003-298465 A

  In the above prior art, the direction of the main lobe can be set variably, and the polarization plane can also correspond to a plurality of modes. However, for the polarization plane, it is only possible to switch between linearly polarized waves and circularly polarized waves, and because circularly polarized waves are used for radio tags that normally have a linear antenna such as a dipole antenna, There is a drawback that the communication distance becomes relatively short (in other words, communication becomes impossible when the communication distance becomes long).

  An object of the present invention is to provide an interrogator that can reliably perform wireless communication with a wireless tag circuit element regardless of the posture of the wireless tag even at a relatively long distance.

The first invention is an antenna means for performing wireless communication with the RFID tag circuit element to be interrogated, a main lobe control means for repeatedly changing the direction or position of the main lobe by the antenna means, and the main lobe control means When the direction or position of the main lobe of the antenna means changes due to, the plane of polarization of the antenna means during wireless communication is changed so that a plurality of modes are possible at least in the same main lobe direction or position. It has tag attitude | position detection means which detects the attitude | position direction of the said RFID tag circuit element according to the communication result of a polarization plane control means and the said RFID tag circuit element via the said antenna means.

In general, in wireless communication between antennas, the communication sensitivity is high when the planes of polarization of both are in a parallel relationship, and the communication sensitivity decreases as they become non-parallel and have a crossing angle. Utilizing this property, in the first invention of this application, the tag orientation detection means is in accordance with the result of communication with the RFID tag circuit element by the antenna means, and the polarization plane of the RFID tag circuit element is determined by the antenna means as the communication is better. Assuming that the direction of polarization plane is nearly parallel, the orientation direction of the RFID circuit element can be detected.

According to a second invention, there is provided signal strength detection means for detecting the signal strength received from the antenna means in the first invention, wherein the tag attitude detection means is configured to detect the wireless signal based on a detection result of the signal strength detection means. It is characterized by detecting the orientation direction of the tag circuit element.

  As the signal strength detected by the signal strength detection means is larger, the tag orientation detection means regards that the polarization plane of the RFID tag circuit element is substantially parallel to the polarization plane direction of the antenna means, and thereby the orientation direction of the RFID tag circuit element ( Including the posture of the affixed article).

According to a third invention, there is provided storage means for storing a plurality of signal intensity values respectively detected by the signal intensity detection means in a plurality of different polarization planes in the second invention, wherein the tag attitude detection means is the memory The posture direction of the RFID circuit element is detected according to the mode of the polarization plane that gives the maximum signal intensity value stored in the means.

  When the signal strength detected by the signal strength detection means is the largest, the polarization plane of the RFID circuit element is closest to the direction of the polarization plane of the antenna means. The orientation direction of the RFID tag circuit element can be detected by storing and extracting the maximum one and determining the polarization plane direction.

According to a fourth aspect of the present invention, the tag according to any one of the first to third aspects of the present invention, according to a communication result with the position correcting RFID circuit element disposed in a predetermined target communication area via the antenna means. Data correction means for correcting detection reference data of the posture detection means is provided.

  For example, a position correction RFID circuit element is arranged in advance at a certain position within a predetermined target communication area, and when it communicates with this, detection reference data on the interrogator side (reference position for specifying position and direction) Or the reference direction or the like is corrected by the data correction unit, the tag posture detection unit can detect the tag posture direction with high accuracy and with less error.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the invention, the wireless communication is performed according to a result of communication with the output setting RFID tag circuit element disposed in a predetermined target communication area via the antenna unit. It has the transmission control means which controls the transmission signal output at the time of communication, It is characterized by the above-mentioned.

  For example, an output setting RFID tag circuit element is disposed in advance in a predetermined position such as an extension of a predetermined target communication area, and at least the transmission control means can perform good communication with the output setting RFID tag circuit element. By controlling the transmission signal output, the entire target communication area can be reliably set as the communicable area.

In a sixth aspect based on the fifth aspect , the transmission control means performs transmission during the wireless communication according to the direction or position of the main lobe changed by the main lobe control means based on the shape of the target communication area. The signal output is changed.

  For example, based on the shape of the target communication area, the output setting RFID circuit element is arranged at the position where the distance from the antenna means is the smallest or the position where the distance from the antenna means is the maximum, The transmission control means controls the transmission signal output so that good communication can be performed without excess or deficiency according to the difference in distance, so that it is possible to reliably communicate over the entire target communication area while preventing wasteful power consumption. It can be an area.

  [0040]

  [0041]

A seventh invention is characterized in that, in any one of the first to sixth inventions, the antenna means is a Yagi antenna having both a transmitting antenna function and a receiving antenna function.

  Even when using a Yagi antenna that also serves for transmission and reception, combining the main lobe repetitive change operation and the change operation of the polarization plane, by matching the polarization plane with the Yagi antenna and the RFID circuit element with high probability, Wireless communication with the RFID tag circuit element can be reliably performed even at a relatively long distance.

  According to the present invention, wireless communication with a wireless tag circuit element can be performed with high sensitivity regardless of the posture of the wireless tag even at a relatively long distance.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. This embodiment is an example in which the present invention is applied to, for example, a floor monitor in a building, and performs a main lobe repetitive change operation and a polarization plane change operation, which will be described later, by a mechanical configuration.

  FIG. 1 is a system configuration diagram showing an outline of a wireless tag detection system using a reader according to the present embodiment.

  In FIG. 1, this wireless tag detection system S includes a reader 100 that is an interrogator for detecting a wireless tag in a floor FL of a predetermined area, and an appropriate communication network (line, wireless). Etc.) It is composed of an operation / display device (management server) 500 connected by NW. An instruction signal or the like by an operation input in the management server 500 is output to the reader 100 via the communication network NW, and a detection signal or the like for the detection (search) target wireless tag T is output from the reader 100 to the management server 500. .

  The management server 500 is composed of, for example, a personal computer, and includes an operation unit (operation unit), a display unit, a CPU, a ROM, a RAM, and the like. The operation unit includes appropriate keys, buttons, switches, pads, and the like as operation input means, and can perform various operation inputs related to display, search, and the like.

  FIG. 2 is a side view of the external appearance of the reader 100 in a state installed on the side wall of the floor FL as seen from the side.

  In FIG. 2, the reader 100 includes a fixed main body 101 that includes a control unit that will be described later and is directly fixed to the side wall WL, a support shaft 102 that is fixedly projected from the fixed main body 101, and the support shaft 102. An angle adjustment hinge 103 provided at the tip of the head and a swinging drive (direction drive means, main lobe control means) 107. The swinging driver 107 is provided between the fixed shaft 104 connected to the angle adjusting hinge 103, the rotating shaft 105 arranged in series with the fixed shaft 104, and the fixed shaft 104 and the rotating shaft 105. And a swinging motor 106 capable of rotationally driving the two shafts 104 and 105 relatively around the axis.

  The reader 100 also includes an antenna rotation shaft 108 provided in an arrangement orthogonal to the rotation shaft 105, an antenna rotator (rotation drive means, polarization plane control means) 110 fixed to the tip of the rotation shaft 105, An antenna rotation motor 109 provided inside the antenna rotator 110 and capable of rotating the antenna rotation shaft 108 about its axis, and a radiator (details will be described later) arranged perpendicular to the tip of the antenna rotation shaft 108. The antenna (device side antenna, antenna means) 111 is fixed.

  The angle adjustment hinge 103 can be fixed at an arbitrary angle by rotating the fixed shaft 104 of the swinging driver 107 so as to face up and down. In the example shown in FIG. The shaft 108 is fixed at an angle that makes the posture substantially horizontal.

  In the swinging driver 107, the swinging motor 106 is connected between the fixed shaft 104 and the rotating shaft 105 through a gear mechanism (not shown), for example, and the swinging motor 106 is connected to the inside of the fixed main body 101. The antenna rotator 110 and the antenna 111 are swung in any rotation direction (around the axis of the rotation shaft 105) via a rotation shaft 105 by a control signal input from a control unit described later provided in (See FIG. 3 shown later).

  The antenna rotator 110 is formed, for example, in a cylindrical shape as a whole and has an antenna rotation shaft 108 protruding from the center of one end surface thereof. An antenna rotation motor 109 inside the antenna rotator 110 is, for example, a control unit described later. The antenna rotation shaft 108 is rotationally driven through a gear mechanism (not shown) in accordance with a control signal from.

  FIG. 3 is a top view of the reader 100 installed on the side wall of the floor FL as viewed from the direction III in FIG.

  In FIG. 3, the antenna rotator 110 and the antenna 111 are driven to swing by the swing driver 107 indicated by a broken line, so that the main lobe M of the antenna 111 is rotated around the rotation axis of the swing driver 107 (in FIG. 3). The head is continuously driven in the swing direction (A rotation direction) (= repetitive change operation of the swing behavior of the main lobe M).

  FIG. 4 is a front view of the reader 100 installed on the side wall of the floor FL as seen from the direction IV in FIG.

  In FIG. 4, the antenna 111 in this example includes a radiator 111a composed of a centrally fed half-wave dipole, and a waveguide 111b and a reflector 111c arranged in parallel so as to sandwich the radiator 111a. It is a three-element type Yagi antenna having one by one, and the director 111b, the radiator 111a and the reflector 111c are integrally fixed by the same supporter (conductor shaft) 111d at each central portion. The central feeding portion 111a is orthogonally fixed to the antenna rotation shaft 108 of the antenna rotator 110. With such a configuration using the Yagi antenna, the direction of the main lobe M (directivity direction) by the antenna 111 is positioned on a straight line parallel to the axis of the antenna rotation shaft 108. Further, an electric field (an example of the direction is represented by E. Refer to FIG. 8 to be described later) is generated across the propagation direction of the radio wave radiated from the antenna 111 including the director 111b, the radiator 111a, and the reflector 111c. In this example, the polarization plane H that is a plane including the vibration direction of the electric field is a plane including the radiator 111a, the waveguide 111b, and the reflector 111c (in other words, the polarization direction is parallel to the radiator 111a). (See FIGS. 2 and 3). The figure conceptually shows the polarization plane H. Note that the Yagi antenna is shown as an example of the antenna 111, but the antenna 111 is not limited to this as long as it has directivity. For example, a planar antenna such as a patch antenna may be used.

  Further, the antenna rotation shaft 108 (see FIG. 3) and the antenna 111 are driven to rotate around the axis of the antenna rotation shaft 108 by driving the antenna rotation motor 109 provided in the antenna rotator 110 (see FIG. 3). Thus, the direction of the polarization plane H radiated from the antenna 111 is rotated (= polarization plane changing operation) so as to switch to one of two angular positions that differ by 90 ° around the axis of the antenna rotation axis 108.

  FIG. 5 is a functional block diagram showing a functional configuration of the reader 100. Parts equivalent to those in FIGS. 2 to 4 are given the same reference numerals, and description thereof will be omitted as appropriate.

  In FIG. 5, in this example, control signals for driving are output to the swing motor 106 and the antenna rotation motor 109, respectively, inside the fixed main body portion 101 that is directly fixed to the side wall of the floor FL, and the antenna 111 is provided. The control part 120 which performs communication control via is provided.

  The control unit 120 includes a CPU (Central Processing Unit) 121, a network communication control unit 122 that controls signal exchange via the network NW, a memory 123 including, for example, a RAM and a ROM, and a command from the CPU 121. In response to this, the swing motor driving unit 124 that outputs a control signal to the swing motor 106 provided in the swing drive unit 107, and the antenna provided in the antenna rotator 110 in response to a command from the CPU 121. An antenna rotation motor driving unit 125 that outputs a control signal to the rotation motor 109 and an RF communication control unit 140 that performs communication control with the antenna 151 provided in the wireless tag T via the antenna 111 are provided. The rotation angle of the swing motor 106 and the antenna rotation motor 109 is controlled by known rotation angle control, such as detecting the rotation angle using a rotary encoder or using a stepping motor for the motor itself. Just do it.

  FIG. 6 is a block showing an example of the functional configuration of the RFID circuit element To including the antenna 151 provided in the RFID tag T attached to the article / member or the like to be searched by the reader 100 described above. FIG.

  In FIG. 6, the RFID circuit element To is connected to the reader 151 and the antenna 151 (tag-side antenna) for transmitting and receiving signals in a non-contact manner using a high frequency such as UHF band or microwave band, and the antenna 151. IC circuit unit 150.

  The IC circuit unit 150 includes a rectification unit 152 that rectifies the carrier wave received by the antenna 151, and a power source unit 153 that accumulates energy of the carrier wave rectified by the rectification unit 152 and serves as a driving power source for the IC circuit unit 150. A clock extraction unit 154 that extracts a clock signal from the carrier wave received by the antenna 151 and supplies the clock signal to a control unit (described later) 157; a memory unit 155 that functions as an information storage unit that can store a predetermined information signal; A modulation / demodulation unit 156 connected to the antenna 151, and a control unit 157 for controlling the operation of the RFID circuit element To via the rectification unit 152, the clock extraction unit 154, the modulation / demodulation unit 156, and the like are provided. .

  The modem unit 156 demodulates the communication signal received from the antenna of the reader 100 (described later) received by the antenna 151, and receives the carrier wave received from the antenna of the reader 100 based on the return signal from the control unit 157. Modulated reflection.

  The control unit 157 interprets the received signal demodulated by the modulation / demodulation unit 156, generates a return signal based on the information signal stored in the memory unit 155, and performs basic control such as returning by the modulation / demodulation unit 156. Execute proper control.

  The clock extraction unit 154 extracts a clock component from the received signal and extracts the clock to the control unit 157, and supplies the control unit 157 with a clock corresponding to the speed of the clock component of the received signal.

  FIG. 7 is a functional block diagram showing the detailed configuration of the RF communication control unit 140 together with the antenna 111.

  In FIG. 7, the antenna 111 is composed of a single Yagi antenna serving as both a transmission antenna and a reception antenna.

  The RF communication control unit 140 has access to the information (RFID tag information) of the IC circuit unit 150 of the RFID circuit element To via the antenna 111 (reading or writing). Access information for reading out information by processing a signal read from the IC circuit unit 150 of the RFID circuit element To and accessing the IC circuit unit 150 of the RFID circuit element To Is connected to the CPU 121 including the function of generating.

  The transmission unit 212 transmits a signal to the RFID circuit element To through the antenna 111, and accesses (reads / writes) the RFID tag information of the IC circuit unit 150 of the RFID circuit element To. And a carrier wave generated by the carrier wave generator based on a signal supplied from the CPU 121 (in this example, amplitude modulation based on a “TX_ASK” signal from the CPU 121). Transmission multiplier circuit 216 (in the case of “TX_ASK signal”, an amplification factor variable amplifier or the like may be used), and a modulated wave modulated by transmission multiplier circuit 216 is amplified (in this example, “TX_PWR” signal from CPU 121) And a transmission amplifier 217 that amplifies the amplification factor). The carrier wave generated by the carrier wave generation unit is preferably set to a frequency of 300 MHz or more, preferably near 900 MHz or near 2.45 GHz, and the output of the transmission amplifier 217 is transmitted to the antenna via the transmission / reception separator 214. 111 is supplied to the IC circuit unit 150 of the RFID circuit element To.

  The reception unit 213 receives the first reception multiplication circuit 218 that multiplies the reflected wave from the RFID circuit element To received by the antenna 111 and passed through the transmission / reception separator 214 and the carrier wave generated by the carrier wave generation unit, and the reception thereof. A first bandpass filter 219 for extracting only a signal of a necessary band from the output of the first multiplication circuit 218, a reception first amplifier 221 for amplifying the output of the first bandpass filter 219, and the reception first amplifier A first limiter 220 that further amplifies the output of 221 and converts it into a digital signal, a reflected wave from the RFID circuit element To that is received by the antenna 111 and passed through the transmission / reception separator 214, and generated after being generated by the carrier wave generation unit. A reception second multiplication circuit 222 that multiplies the carrier whose phase is delayed by 90 ° by the phase shifter 227, and its reception second multiplication circuit 2 2, a second band pass filter 223 for extracting only a signal of a necessary band from the output of 2, a reception second amplifier 225 for amplifying the output of the second band pass filter 223, and an output of the reception second amplifier 225. Further, a second limiter 224 that amplifies and converts it into a digital signal is provided. The signal “RXS-I” output from the first limiter 220 and the signal “RXS-Q” output from the second limiter 224 are input to the CPU 121 and processed.

  The outputs of the reception first amplifier 221 and the reception second amplifier 225 are also input to an RSSI (Received Signal Strength Indicator) circuit 226 (signal intensity detection means), and a signal “RSSI” indicating the intensity of these signals is input to the CPU 121. Is input. In this manner, the RF communication control unit 140 of the reader 100 according to the present embodiment demodulates the reflected wave from the RFID circuit element To by IQ orthogonal demodulation.

  The CPU 121 is a so-called microcomputer, and although not shown in detail, the CPU 121 is composed of a central processing unit such as a CPU, a ROM, a RAM, and the like, and is a program stored in advance in the ROM using the temporary storage function of the RAM. The signal processing is performed according to the above. The CPU 121 inputs a received signal from the receiving unit 213 described above, performs predetermined arithmetic processing, and outputs an amplification control signal, a modulation control signal, and the like to the transmitting unit 212 described above.

  The CPU 121 exchanges information with a route server (not shown), another terminal, a general-purpose computer, an information server, and the like via, for example, the network communication control unit 122 (or another input / output interface). It may be configured as possible.

In the above configuration, the most significant feature of the reader 100 of the present embodiment is that the direction of the main lobe M by the antenna 111 is repeatedly changed by the swing driver 107, and at this time, at least the same by the antenna rotator 110. The mode of the polarization plane H (rotation angle in this example) of the antenna 111 is changed so that a plurality of modes are possible in the direction of the main lobe M.

  Particularly in this embodiment, in conjunction with one unit in the repetitive operation of the swing behavior of the swing driver 107, the antenna rotator 110 changes the direction of the polarization plane H of the antenna 111 to a predetermined first direction. The two directions (modes) of the second direction substantially orthogonal to the first direction are sequentially switched. FIG. 8 is a diagram schematically showing a combination of the swing behavior and the antenna rotation operation performed by the reader 100 of the present embodiment, and FIG. 8A is a diagram showing the swing behavior in one direction. FIG. 8B is a diagram showing the swing behavior in the reverse direction. In addition, in order to avoid the complexity of illustration, only the antenna rotator 110, the antenna rotation shaft 108, and the antenna 111 are shown, and illustration of other members is omitted.

  In FIG. 8 (a), in the forward path as one direction of the swing behavior, the radiator 111a of the Yagi antenna 111 is in a vertical direction (front and back directions in the drawing). Thus, the plane of polarization H from the antenna 111 is a plane including the radiator 111a in the vertical direction. By performing the above-described swinging behavior in the forward direction in this state, the main lobe M, which is the directing direction of wireless communication, can reach a wide substantially fan-shaped range, and in this range, the polarization plane of the tag-side antenna 151 is substantially the same. The plane of polarization substantially coincides with the RFID circuit element To having the same vertical orientation, and high communication sensitivity can be ensured.

  Then, after finishing the forward swing motion, the antenna 111 is rotated by 90 ° by the antenna rotator 110 so that the radiator 111a of the antenna 111 is in a lateral direction (a direction parallel to the paper surface in the drawing). Thus, the plane of polarization H from the antenna 111 is a plane including the radiator 111a in the lateral direction. In this state, by performing the backward swing motion shown in FIG. 8B, the main lobe M can reach a wide range as in the forward path, and in this range, the tag side antenna 151 The plane of polarization substantially coincides with the RFID circuit element To whose polarization plane is substantially the same in the lateral direction, and high communication sensitivity can be ensured.

As described above, in the reader 100 of the present embodiment, when performing wireless communication with the RFID tag circuit element To that is the question via the antenna 111, the direction of the main lobe M of the antenna 111 is first determined by the swing driver 107. It is changed repeatedly. The Repeated changing operation can be reach over a relatively wide range of the main lobe M, also allows suppressing the RFID circuit element To located relatively far distance communicable area. At this time, the polarization plane H of the antenna 111 is changed by the antenna rotator 110, and at least a plurality of different polarization planes in the same main lobe direction (in the above example, the polarization plane H including the radiator 111a in the vertical direction). And two modes of the polarization plane H including the radiator 111a in the horizontal direction are realized.

  Thereby, even if the polarization plane coincides between the antenna 111 and the antenna 151 provided in the RFID tag circuit element To of the RFID tag T in one aspect, the antenna 111 and the wireless There is a high possibility that the plane of polarization of the tag circuit element To and the antenna 151 can coincide with each other, and good communication sensitivity can be ensured. As described above, by combining the repetitive changing operation of the main lobe M and the changing operation of the polarization plane H, regardless of the posture of the wireless tag T (or an article to which the wireless tag T is attached), and at a relatively far distance. Even if it exists, radio | wireless communication with the radio | wireless tag circuit element To can be performed reliably.

  In the present embodiment, in particular, the antenna rotator 110 changes the mode (direction) of the polarization plane H of the antenna 111 substantially in synchronization with one unit of the repetitive operation of the swing driver 107 (outward path and backward path). Thus, the repetitive changing operation of the main lobe M and the changing operation of the polarization plane H are combined in an interlocking manner, and the polarization plane can be matched with the antenna 111 and the RFID circuit element To with high probability.

  In this embodiment, in particular, the antenna rotator 110 has a polarization plane H at the time of wireless communication of the antenna 111 with a plurality of predetermined modes (in this example, the polarization plane including the radiator 111a in the vertical direction). H and two modes of polarization plane H including radiator 111a in the horizontal direction) are sequentially switched to change the polarization plane coincidence with RFID circuit element To while sequentially switching polarization plane H of antenna 111. It is possible to search and match the polarization planes with high probability.

  The first embodiment can be variously modified without departing from the spirit and technical idea of the present invention. Hereinafter, such modifications will be described in order.

(1-1) When the main lobe is repeatedly changed by parallel movement In the first embodiment, the main lobe M is repeatedly changed by the swinging behavior of the antenna 111. However, the present invention is not limited to this. The main lobe M may be repeatedly changed by the parallel movement of the antenna 111.

  FIG. 9 is a diagram schematically showing a translation operation and an antenna rotation operation of a modification in which the main lobe is repeatedly changed by translation, and FIG. 9A is a diagram showing the translation operation in one direction. FIG. 9B is a view showing the parallel movement operation in the reverse direction, and corresponds to FIG. 8 in the first embodiment. In addition, in order to avoid the complexity of illustration, only the antenna rotator 110, the antenna rotation shaft 108, and the antenna 111 are shown, and illustration of other members is omitted.

  In FIG. 9A, in the forward path as one direction of the parallel movement operation, the attitude of the radiator 111a of the Yagi antenna 111 in the vertical direction (the direction toward the front and the substantially back side in the drawing). Thus, the plane of polarization H from the antenna 111 is defined as a plane (first direction) including the radiator 111a in the vertical direction. Then, after completing the parallel movement operation of the forward path, the antenna 111 is rotated by 90 ° by the antenna rotator 110 so that the radiator 111a of the antenna 111 is in a horizontal direction (a direction substantially parallel to the paper surface in the drawing). Thus, the plane of polarization H from the antenna 111 is set as a plane (second direction) including the radiator 111a in the lateral direction. Although not particularly illustrated, the parallel movement operation of the antenna rotator 110 can be performed using a known actuator such as a slider using a feed screw or a linear motor.

  In the present modification, the linear main lobe M, which is the directing direction of the wireless communication, can reach a wide rectangular range by the parallel movement operation of the round-trip path, and within the rectangular range as in the first embodiment. Thus, the polarization plane H of the antenna 111 and the polarization plane of the RFID circuit element To can be matched with high probability. As a result, wireless communication with the RFID circuit element To can be reliably performed regardless of the attitude of the RFID tag T (or an article to which the RFID tag T is attached) and even at a relatively long distance.

(1-2) When the main lobe is repetitively changed by the swiveling behavior of the lap In the first embodiment, the repetitive changing operation of the main lobe M is performed by the swinging behavior of the antenna 111. For example, the repetitive change operation of the main lobe M may be performed by, for example, the orbital swing motion.

  FIG. 10 is an external side view of a modified example of the reader 300 in which the main lobe M is repeatedly changed according to the swivel behavior, and corresponds to FIG. 2 in the first embodiment. Parts equivalent to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  In FIG. 10, the main body fixing portion 301 of the reader 300 of this modification is fixedly installed on the ceiling RF of the floor FL, and the antenna rotator 110 includes two pairs of rotating shafts 302 and 303 arranged orthogonally and one ring. It is installed on the main body fixing portion 301 via a known universal joint (305) 305. In addition, a circling head swing motor 306 is provided at the center of the main body fixing portion 301, and the antenna rotator 110 is disposed in an inclined posture direction on the end surface opposite to the side from which the antenna rotation shaft 108 protrudes. Further, the rotation direction of the rotation shaft 306 is connected to the rotating shaft 306 via the link 307 so that the antenna rotating shaft 108 is arranged at a certain elevation angle with respect to the wall surface (horizontal plane) of the ceiling RF. .

  In the above configuration, the orbital swing motor (main lobe control means) 308 is configured by the orbital swing motor 306, the universal joint 305, and the link 307. According to this orbital swinging driver 308, the mainlobe M positioned in the extending direction of the antenna rotation shaft 108 is fixed to the wall surface of the ceiling FR by continuously rotating the orbital swinging motor 306 in one direction. It is possible to perform a repetitive change operation by the orbital swinging behavior over the entire circumference (360 °) while forming the elevation angle.

  The antenna 111 is rotated by 90 ° by the antenna rotator 110 every time the turning motion of the main lobe M makes one rotation (360 °) (in the above example, the first direction is shifted by 90 ° from the second direction). Direction → first direction shifted by 90 ° →...) The direction of the radiator 111 a of the Yagi antenna 111 and its polarization plane H are switched.

In the present modification, the direction or position of the main lobe M is repeatedly changed by using the orbital swing behavior in one direction (clockwise or counterclockwise) by the orbital swing driver 308 as described above. A repetitive change can be realized that repeats the same main lobe direction many times (eg, with the same period). As in the first embodiment, the polarization plane H of the antenna 111 and the polarization plane of the RFID circuit element To can be matched with high probability.

  In this modification, the antenna 111 is rotated by 90 ° by the antenna rotator 110 every time the swivel behavior of the main lobe M makes one rotation (360 °), and the radiator 111a of the Yagi antenna 111 and its polarization plane The direction of H is switched, but the present invention is not limited to this, and the attitude of the antenna 111 (in other words, the direction of the polarization plane H) is changed by 90 ° at a timing other than the rotation of the main lobe M by one revolution (360 °). You may make it switch. In that case, the swivel behavior and polarization plane of the main lobe M are covered so that the entire swivel azimuth of the main lobe M can be covered with both polarization planes H in the first direction and the second direction 90 degrees different from each other. What is necessary is just to set so that the change operation of H may be repeated.

(1-3) When changing the transmission signal output during wireless communication according to the shape of the target communication area In the first embodiment, over the entire behavior range of the swing behavior (circular swing motion) of the main lobe M. Although wireless communication is always performed with the same transmission signal output, the present invention is not limited to this, and the output value may be changed according to the shape of the target communication area.

  FIG. 11 is a diagram for explaining a state in which the transmission signal output during wireless communication is controlled based on the shape of the floor FL surrounded by walls on all four sides as a target communication region. FIG. FIG. 11B is a diagram illustrating a state in which the main lobe M reaches the wall surface at a short distance. In the illustrated example, a case is shown in which the reader 300 according to the second modified example installed on the ceiling RF of the floor FL and performing the swivel behavior of the main lobe M is used.

  In FIG. 11A, the reader 300 installed on the ceiling RF of the floor FL turns the main lobe M toward the lower corner CN surrounded by the floor surface of the floor FL and two orthogonal side walls by the orbital swing behavior. It is in a state. At this time, the main lobe M from the reader 300 reaches the wall surface at a relatively long distance, and a relatively high transmission signal output is required to make the communicable area up to the lower corner CN.

  In FIG. 11B, the reader 300 is in a state in which the main lobe M is directed in a direction orthogonal to the side wall WL closest to the reader 300 due to the circling head swing behavior. At this time, the main lobe M from the reader 300 reaches the wall surface at a relatively short distance, and the reachable portion at the wall surface WL can be made a communicable area with a relatively low transmission signal output. .

  In this modification, when performing output control according to the target communication area shape as described above, an output setting RFID circuit element ToP (not shown) for performing output setting is provided at a predetermined location in the target communication area. (For example, in the above example, it is provided on the side wall WL or the lower corner CN), and the transmission signal output at the time of wireless communication is controlled (= transmission control means) according to the communication result with respect to the output setting RFID circuit element ToP.

  Here, the RFID tag circuit element ToP for output setting is arranged in advance such that its orientation is determined so that the polarization plane of the tag-side antenna 151 coincides with the polarization plane H of the apparatus-side antenna of the reader 300. The reader 300 secures an output value so that at least good communication with the output setting RFID circuit element ToP can be performed, and the reader 300 is relatively far from the reader 300 like the lower corner CN as shown above. When the main lobe M is directed to a distant position, a relatively large transmission signal is output. When the main lobe M is directed to a position relatively close to the reader 300 such as the wall surface WL, a relatively small transmission signal is output.

  As described above, in the normal floor, when the main lobe M is repeatedly changed, the distance from the antenna 111 to the boundary (floor wall surface) of the target communication area is almost always changed. Variable control of the transmission signal output to allow good communication without excess or deficiency according to the difference prevents wasteful power consumption and ensures communication over the entire target communication area (the entire circumference of the swivel behavior) It can be an area. At this time, by setting the output setting RFID circuit element ToP provided at an appropriate location as described above as a transmission target, it is possible to perform more reliable communication without waste of output. Needless to say, the transmission signal output may be controlled by executing a program reflecting the shape.

( 1-4 ) Others In the above embodiment, the antenna rotation motor 109 rotationally drives the antenna rotation shaft 108 to change the mode of the polarization plane H by the antenna 111 (in this example). I can't. That is, for example, the support member of the antenna rotation shaft 108 such as the antenna rotator 110 itself may be rotationally driven by an appropriate driving unit, and thereby the aspect of the polarization plane H may be changed. In this case, the same effect is obtained. Further, in the above embodiment, the direction of the main lobe M by the antenna 111 is changed by rotating the antenna rotator 110 itself by the driving force of the swing motor 106, but the present invention is not limited to this. That is, only the antenna rotating shaft 108 or the antenna 111 may be driven to swing by an appropriate driving unit, and thereby the direction of the main lobe M may be changed. In this case, the same effect is obtained.

  Next, a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the repetitive changing operation of the main lobe M and the changing operation of the polarization plane H are performed by an electrical configuration. In each figure, the same reference numerals are given to the same parts as those in the first embodiment, and the description will be omitted as appropriate.

  FIG. 12 is a functional block diagram showing details of the functional configuration of the reader 400 of the present embodiment, and corresponds to FIG. 5 in the first embodiment.

  In FIG. 12, the reader 400 includes a control unit 120 and an antenna (antenna means) 130.

  The control unit 120 includes a CPU 121, a network communication control unit 122, a memory 123 (storage means), and an RF communication control unit 140 ′ that performs communication control with the antenna 151 provided in the wireless tag T via the antenna 130. ing.

  FIG. 13 is a functional block diagram showing detailed configurations of the RF communication control unit 140 ′ and the antenna 130, and corresponds to FIG. 7 of the first embodiment.

  In FIG. 13, an antenna 130 includes one transmission antenna (antenna element) 10 and a plurality (eight in this example) of reception antennas (antenna elements) 11A, 11B, 11C, 11D, 11E, 11F, 11G, and 11H ( However, in order to prevent complications, some parts are omitted, and the same applies hereinafter. Each of the receiving antennas 11A to 11H is composed of a dual-purpose antenna (microstrip antenna) in which two antennas are integrally formed so that polarization planes orthogonal to each other can be electrically switched. A polarization plane changeover switch (switching means, polarization plane control means) 12 that is switched by a switching signal from the CPU 121 is provided.

  The RF communication control unit 140 ′ receives information (wireless tag information) of the IC circuit unit 150 of the RFID circuit element To via the transmitting antenna 10 and the receiving antennas 11A, 11B, 11C, 11D, 11E, 11F, 11G, and 11H. Phase control units (control means, main lobe) for transmitting unit 212 and receiving unit 213 for accessing (reading or writing) and receiving antennas 11A, 11B, 11C, 11D, 11E, 11F, 11G, and 11H, respectively. Control means) 203A, 203B, 203C, 203D, 203E, 203F, 203G, 203H and a multiplexer 205 for adding outputs from these phase control units 203A to 203H, and an IC circuit of the RFID circuit element To Processing the signal read from the unit 150 to read information And it is connected to the CPU121 comprising the function of generating the access information for accessing to the IC circuit part 150 of the RFID circuit element To.

  The phase control units 203A, 203B, 203C, 203D, 203E, 203F, 203G, and 203H receive the phase control signal from the CPU 121, and receive antennas 11A, 11B, 11C, 11D, 11E, 11F, 11G, and 11H in response thereto. The phase shifters 206A, 206B, 206C, 206D, 206E, 206F, 206G, and 206H for variably setting the phase of the received radio signal at the input signal from the CPU 121 and the phase shifters 206A, 206B, Variable gain amplifiers 208A, 208B, 208C, 208D, 208E, 208F, 208G that variably amplify signals input from 206C, 206D, 206E, 206F, 206G, 206H and output the signals to the multiplexer 205. , 208H with .

  The transmission unit 212 transmits a signal to the RFID circuit element To via the transmission antenna 10, and is equivalent to the transmission unit 212 in FIG.

  The receiving unit 213 is substantially the same as the receiving unit 213 in FIG. 7, and is different in that it is received by the receiving antennas 11A, 11B, 11C, 11D, 11E, 11F, 11G, and 11H and the phase control unit 203A. , 203B, 203C, 203D, 203E, 203F, 203G, and 203H, the reflected wave from the RFID circuit element To that is multiplexed by the multiplexer 205 is generated by the reception first multiplier circuit 218 by the carrier wave generation unit. It is the point that multiplies with the carrier wave.

  Further, the CPU 121 performs a predetermined calculation process after inputting the reception signal from the reception unit 213 described above, and performs the amplification control signal and the modulation control signal to the transmission unit 212 described above, and the phase to the phase control units 203A to 203H. A control signal, a switching signal to the polarization plane changeover switch 12 of each of the receiving antennas (shared antennas) 11A to 11H, and the like are output.

  Hereinafter, dual-purpose antennas constituting the reception antennas 11A to 11H will be described in detail.

  FIG. 14A is a side view showing the detailed structure of the dual-purpose antenna, and FIG. 14B is a cross-sectional view thereof. 14 (a) and 14 (b), the dual-purpose antenna 11 includes a microstrip antenna element 11a on one side (upper side in the figure) and a ground plane 11b on the other side (lower side in the figure). A dielectric 11c is provided in the middle so as to be sandwiched between the two.

  Through holes 11ba and 11ca are provided at two locations in the radial direction of the ground plane 11b and the dielectric 11c, respectively. A microstrip line 50 serving as a feed line to the dual-purpose antenna 11 having one end connected to the RF communication control unit 140 ′ (see FIG. 15 described later) is connected to the polarization plane changeover switch 12, and this polarization plane changeover switch. Two feed lines 50A connected so as to branch from 12 are extended and connected to feed points P1 and P2 provided at two locations of the microstrip antenna element 11a through through holes 11ba and 11ca, respectively. Yes.

  FIG. 15A is a perspective view illustrating the schematic top surface structure of the microstrip antenna element 11a and the dielectric 11c, and FIG. 15B is a perspective view illustrating the schematic bottom surface structure of the ground plane 11b. FIG. 15C is an explanatory diagram showing the electrical connection relationship between the dual-purpose antenna 11 and the RF communication control unit 140 ′.

  15A to 15C, on the antenna element 11a, the first polarization for causing the dual antenna 11 to have the first polarization plane Hh in one direction as the two feeding points P described above. A wave feed point P1 and a second polarization feed point P2 for causing the dual antenna 11 to generate a second polarization plane Hv in a direction orthogonal to the first polarization plane Hh are provided.

  The polarization plane changeover switch 12 included in each dual-purpose antenna 11 constitutes a first polarization plane Hh in a predetermined direction when switched to the first polarization side in FIG. A signal is received with high sensitivity from the RFID circuit element To constituting the signal, and is guided from the first polarization feed point P1 to the phase control unit 203 via the polarization plane changeover switch 12. On the other hand, the polarization plane changeover switch 12 constitutes a second polarization plane Hv in a direction orthogonal to the first polarization plane Hh when switched to the second polarization side in FIG. A signal is received with high sensitivity from the RFID circuit element To that constitutes the plane of polarization of the direction, and is guided from the second polarization feed point P2 to the phase control unit 203 via the plane of polarization switch 12.

  According to such dual-purpose antenna 11, the first polarization plane Hh generated by feeding to the first polarization feed point P1 is the second polarization plane Hv generated by feeding to the second polarization feed point P2. And substantially orthogonal to each other.

  FIG. 16 is a flowchart showing a control procedure performed by the CPU 121 provided in the control unit 120 of the reader 400 in order to perform monitoring (detection of the wireless tag T) in the floor FL as described above.

  In FIG. 16, when the operation start instruction signal transmitted from the management server 500 (see FIG. 1) to the reader 400 is input to the CPU 121 via the network NW and the network communication control unit 122, this flow is started.

  First, in step S101, a switching signal is output to the polarization plane changeover switch 12 of each reception antenna 11A to 11H, and the polarization plane of each reception antenna 11A to 11H is set to the first polarization plane Hh.

  Next, the process proceeds to step 102 where the main lobe direction angle θ is set to the initial angle θa. Here, the reader 400 performs so-called phased array control in which the direction of the main lobe M (= direction of reception directivity) of each of the reception antennas 11A to 11H is changed to a single direction while searching. It is. At this time, an angle in the main lobe direction (hereinafter, referred to as a main lobe direction angle as appropriate) from a certain reference position (for example, 0 ° in the right direction from the front as viewed from the reader 400) is defined as θ. The initial angle θa is changed every predetermined increment θSTEP.

  Then, the process proceeds to step S103. In step S103, the phases related to the receiving antennas 11A, 11B, 11C, 11D, 11E, 11F, 11G, and 11H are determined according to the value of the main lobe direction angle θ, and the phase control signal corresponding thereto is sent to the phase control unit 203A. , 203B, 203C, 203D, 203E, 203F, 203G, 203H.

  Specifically, in general, the phase difference of the received signal between adjacent antenna elements of the received radio wave is expressed as (2) where d is the interval between adjacent receive antenna elements, λ is the wavelength of the received radio wave, and θ is the main lobe direction angle. Since π · d · cos θ) / λ, the corresponding phase difference is given to the phase control units 203A to 203H, respectively.

  Thereafter, in step S104, a call signal for the search target RFID tag T from the transmission antenna 10 under the condition that the phases of the reception antennas 11A to 11H are set as described above (in other words, the main lobe direction angle θ is set). The ScrollID signal is output. Specifically, a “TX_ASK” signal is generated and output to the transmission multiplication circuit 216, and the corresponding amplitude modulation is performed in the transmission multiplication circuit 216 to become a “Scroll ID” signal as access information. On the other hand, the CPU 121 generates a “TX_PWR” signal and outputs it to the transmission amplifier 217. The transmission amplifier 217 performs signal amplification at an amplification factor based on the “TX_PWR” signal, and is finally transmitted via the transmission antenna 10. A reply from the RFID circuit element To of the target RFID tag T is urged.

  Thereafter, in step S105, a response signal (= reply signal; wireless tag information such as tag identification information) transmitted from the wireless tag circuit element To of the wireless tag T to be searched in response to the “Scroll ID” signal is received. The signals are received from the antennas 11 </ b> A to 11 </ b> H, the phases are controlled by the phase control units 203 </ b> A to 203 </ b> H, and are taken in via the multiplexer 205 and the receiving unit 213. The received signal strength signal “RSSI” from the RSSI circuit 226 at this time is input, and the value is stored in the memory 123 in step S106.

  In step S107, θ is set in advance as a final value when the main lobe direction angle θ is sequentially changed (for example, when the reader 400 performs a two-round search in the circumferential direction, θEND = θa + 720 °, four rounds) In the case of searching, it is determined whether or not it becomes equal to θEND = θa + 1440 ° or the like. Since θ = θa at first, the determination is not satisfied, and the routine goes to Step S108.

  In step S108, whether θ is an angle obtained by adding an integral multiple of 360 ° (n × 360 °: n = integer) to the initial angle θa, that is, whether the reader 400 has just made n turns in the circumferential direction. If the determination is normal, the process proceeds to step S110. If the determination is satisfied, a switching signal is output to the polarization plane changeover switches 12 of the receiving antennas 11A to 11H in step S109. The wavefront is switched (switching from the first polarization plane Hh to the second polarization plane Hv, or from the second polarization plane Hv to the first polarization plane Hh), and the process proceeds to step S110. In step S110, only a predetermined θSTEP (for example, a value obtained by dividing 360 ° such as θSTEP = 15 ° by an integer) is added, the process returns to step S102, and the same procedure is repeated.

  In this way, steps S103 to S110 are repeated, and θSTEP is added to the θ value in small increments, and the main lobe direction angle θ is maintained while maintaining the direction of the main lobe (directivity) M generated by all the receiving antennas 11A to 11H in a single direction. , And each time the direction of the main lobe M is rotated n times (in this example), the polarization planes of the receiving antennas 11A to 11H are simultaneously switched to the polarization planes orthogonal to the signal transmission, The reception signal is stored each time the reception is repeated.

  In this way, the reader 400 changes the main lobe direction angle θ while adding θSTEP from the initial angle θa, so that the search is performed by shifting (rotating) the main lobe direction angle by θSTEP. Here, by performing a search of at least two rounds (θEND ≧ θa + 720 °), each receiving antenna can be searched for at least one round in the first polarization plane and the second polarization plane. If θ = θEND, the determination in step S107 is satisfied, and the routine goes to step S111.

  In step S111, the directivity direction (tag direction) θT in which the wireless tag T exists (relative to the reader 400) is determined based on the signal strength stored in step S108 during the repetition (for example, the most signal) The main lobe direction angle direction was high intensity).

  Thereafter, the process proceeds to step S112, a tag position information signal including the tag direction θT as tag position information is transmitted to the management server 500 via the network 122 communication unit and the communication network NW, and this flow is finished.

  As described above, in the reader 400 of the present embodiment, the CPU 121 electrically controls, for example, phase shifts and amplitudes of the reception signals at the plurality of reception antennas 11A to 11H, and the mains by the plurality of reception antennas 11A to 11H. The direction or position of the lobe M is changed repeatedly (in this example, rotationally). Since the main lobe M can reach a relatively wide range by this repeated change operation, the RFID circuit element To located at a relatively far distance can be accommodated in the communicable area. At this time, the dual-purpose antennas 11 constituting each of the receiving antennas 11A to 11H are previously provided with a plurality of antennas having different polarization planes, and are switched by the polarization plane changeover switch 12 to selectively use the polarization plane directions as antennas. Are switched, a plurality of different polarization planes (in the above example, two modes of the first polarization plane Hh and the second polarization plane Hv) are realized at least in the same main lobe direction (or position).

  As a result, even in one aspect (first polarization plane Hh in the above example), even if the polarization planes of the antenna 111 and the antenna 151 provided in the RFID tag circuit element To of the RFID tag T are not sufficiently matched. In the other mode (the second polarization plane Hv in the above example), there is a high possibility that the polarization planes of the antenna 111 and the antenna 151 of the RFID tag circuit element To can coincide with each other, thereby ensuring good communication sensitivity. Can do. As described above, by combining the repetitive changing operation of the main lobe M and the changing operation of the polarization plane H, regardless of the posture of the wireless tag T (or an article to which the wireless tag T is attached), and at a relatively far distance. Even if it exists, radio | wireless communication with the RFID circuit element To can be performed reliably.

  In the second embodiment, various modifications can be made without departing from the spirit and technical idea of the second embodiment. Hereinafter, such modifications will be described in order.

(2-1) When detecting the orientation direction of the RFID circuit element To to be detected That is, according to the communication result with the RFID circuit element To via the device-side antenna 130 of the second embodiment, for example, the RFID tag The posture direction of the circuit element To may be detected (= tag posture detection means).

  In general, in wireless communication between antennas, communication sensitivity is high when the polarization planes of both antennas are in parallel relation, and the communication sensitivity decreases as they become non-parallel and have a crossing angle. Using this property, depending on the communication result of the antenna 130 with the RFID circuit element To, the better the communication is (for example, the greater the signal strength of the RSSI circuit 226), the more the polarization plane of the RFID circuit element To is the antenna. Since it can be considered that the direction of polarization plane 130 is nearly parallel, the orientation direction (including the orientation of the attached item) of the RFID circuit element To can be detected based on this.

  Specifically, when executing the flow shown in FIG. 16, a plurality of received signal intensity values respectively detected by the RSSI circuit 226 in a plurality of different polarization plane modes (polarization plane directions) are stored in the memory 123. . Therefore, the received signal intensity value in each of the plurality of polarization plane modes (in the above example, for example, the received signal intensity value maximized at the first polarization plane Hh and the received signal intensity maximized at the second polarization plane Hv). Intensity values) are compared, and the direction of the polarization plane giving the largest one is determined. When the received signal strength is the highest, the plane of polarization of the RFID circuit element To is closest to the direction of the plane of polarization of the antenna 130. It is possible to detect the orientation direction.

(2-2) When performing position detection correction using a RFID circuit element In other words, for example, position correction to a certain position in a predetermined target communication area in advance (a place where precise position measurement has been completed by another method) A wireless tag circuit element ToL is disposed. Then, communication with the RFID circuit element ToL for position correction is performed from the reader side, and position detection data of the RFID circuit element ToL detected on the reader side (reference position and reference direction when specifying the position and direction, etc.) Then, the position measurement data on the reader side is corrected so as to match the position measurement data measured precisely and match the position measurement data (= data correction means). Thereby, the tag attitude | position detection means demonstrated in the modification of said (2-1) can detect the tag attitude | position direction with few errors with high precision.

(2-3) Others In the second embodiment, the polarization plane is switched in more posture directions than the antennas that form two orthogonal polarization planes such as the dual-purpose antenna (reception antenna) 11. By using an antenna that can be configured, it is possible to more reliably perform wireless communication with the RFID circuit element To even at a relatively long distance. Also, in the modified examples of (2-1) and (2-2) above, in more posture directions than the antennas that form two orthogonal polarization planes such as the dual-purpose antenna (receiving antenna) 11. By using an antenna that can be configured by switching the polarization plane, there is an effect that the tag orientation direction can be detected with less error and with high accuracy.

  Further, in the second embodiment, the phase shift control units 203A to 203H hold the directivity by the antenna element so as to increase only in one direction, and control to transmit to the wireless tag T while sequentially changing the direction. Although the case where the phased array control is performed has been described, the present invention is not limited to this. In other words, based on the received signal at each antenna element, adaptive array control for controlling the directivity by each antenna element so as to optimize the reception sensitivity from the communication target (wireless tag T), etc. Directivity control may be performed. In this case, the same effect is obtained.

  It should be noted that the modified examples according to the two embodiments described above can be combined as appropriate regardless of the distinction between the embodiments.

  In the above description, the case where information is read from the IC circuit unit 150 of the RFID circuit element To has been described as an example. However, the present invention is not limited to this, and the RFID circuit element To capable of writing information is provided. The present invention may be applied to the wireless tag information communication device of the wireless tag T. In this case, the same effect is obtained.

  It is assumed that the “Scroll All ID” signal, the “Scroll ID” signal, and the like used above comply with the specifications established by EPC global. EPC global is a non-profit corporation established jointly by the International EAN Association, which is an international organization of distribution codes, and the United Code Code Council (UCC), which is an American distribution code organization. Note that signals conforming to other standards may be used as long as they perform the same function.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1 is a system configuration diagram showing an outline of a wireless tag detection system using a reader according to a first embodiment of the present invention. It is the side view which looked at the external appearance of the reader in the state installed in the side wall of the floor from the side. FIG. 3 is a top view of the reader installed on the side wall of the floor as viewed from the direction III in FIG. 2. It is the front view which looked at the leader of the state installed in the side wall of the floor from the IV direction in FIG. It is a notional block diagram showing the detailed structure of a reader. It is a block diagram showing an example of a functional structure of the radio | wireless tag circuit element with which the radio | wireless tag attached to the articles | goods and member etc. which are the search objects of a reader | leader was equipped. It is a functional block diagram showing the detailed structure of a RF communication control part. It is the figure which showed typically the combination of the swing behavior and antenna rotation operation which are performed by the reader of 1st Embodiment. It is the figure which showed typically the translation operation | movement and antenna rotation operation | movement of the modification which makes the main lobe change operation | movement repeatedly by translation. It is an external appearance side view of the reader | leader of the modification which makes a main lobe change operation | movement repeatedly by a circular head swing behavior. It is a figure explaining a mode that the transmission signal output at the time of radio | wireless communication is controlled based on the shape by making into a target communication area the floor enclosed by the wall on all sides. It is a functional block diagram showing the detail of the functional structure of the reader of 2nd Embodiment. It is a functional block diagram showing the detailed structure of a RF communication control part and an antenna. It is the side view and sectional drawing showing the detailed structure of a combined use antenna. It is the perspective view showing the upper surface schematic structure of a combined use antenna, and explanatory drawing showing electrical connection relation. It is a flowchart showing the control procedure which CPU provided in the control part of the reader | leader performs in order to monitor in a floor.

Explanation of symbols

10 Transmitting antenna (antenna means)
11A to H Receiving antenna, dual-purpose antenna (antenna means)
12 Polarization plane changeover switch (Polarization plane control means)
100 reader (interrogator)
107 Swing drive (main lobe control means)
110 Antenna rotator (polarization plane control means)
111 antenna (antenna means, Yagi antenna)
123 Memory (storage means)
130 Antenna (antenna means)
300 Reader (Interrogator)
308 Orbital swing drive (main lobe control means)
400 Reader (Interrogator)
500 Management server FL floor (target communication area)
S wireless tag detection system T wireless tag To wireless tag circuit element

Claims (7)

Antenna means for performing wireless communication with the RFID tag circuit element to be interrogated;
Main lobe control means for repeatedly changing the direction or position of the main lobe by the antenna means;
When the direction or position of the main lobe of the antenna means is changed by the main lobe control means, at least during the wireless communication of the antenna means so that a plurality of modes are possible in the same direction or position of the main lobe. A polarization control means for changing the polarization plane;
An interrogator comprising tag orientation detection means for detecting the orientation direction of the RFID circuit element in accordance with a result of communication with the RFID circuit element via the antenna means. The interrogator of claim 1 ,
Signal strength detection means for detecting the signal strength received from the antenna means;
The interrogator characterized in that the tag orientation detection means detects the orientation direction of the RFID circuit element based on the detection result of the signal strength detection means. The interrogator according to claim 2 ,
Storage means for storing a plurality of signal intensity values respectively detected by the signal intensity detection means in different polarization planes;
The tag orientation detection means detects the orientation direction of the RFID circuit element in accordance with the aspect of the polarization plane that gives the maximum signal intensity value stored in the storage means. Interrogator to ask. The interrogator according to any one of claims 1 to 3 ,
Data correction means for correcting the detection reference data of the tag attitude detection means according to the result of communication with the position correction RFID circuit element arranged in the predetermined target communication area via the antenna means. A characteristic interrogator. The interrogator according to any one of claims 1 to 4 ,
It has a transmission control means for controlling the transmission signal output at the time of the wireless communication according to the communication result with the power setting RFID circuit element arranged in the predetermined target communication area via the antenna means. Interrogator. The interrogator according to claim 5 ,
The transmission control means changes the transmission signal output during the wireless communication according to the direction or position of the main lobe changed by the main lobe control means based on the shape of the target communication area. vessel. The interrogator according to any one of claims 1 to 6 ,
The interrogator is a Yagi antenna having a transmitting antenna function and a receiving antenna function.

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