WO2019220637A1 - Wireless communication device and wireless communication system - Google Patents

Wireless communication device and wireless communication system Download PDF

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Publication number
WO2019220637A1
WO2019220637A1 PCT/JP2018/019362 JP2018019362W WO2019220637A1 WO 2019220637 A1 WO2019220637 A1 WO 2019220637A1 JP 2018019362 W JP2018019362 W JP 2018019362W WO 2019220637 A1 WO2019220637 A1 WO 2019220637A1
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Prior art keywords
signal
wireless communication
reflector
terminal
reflection coefficient
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PCT/JP2018/019362
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French (fr)
Japanese (ja)
Inventor
裕翔 榊
安藤　暢彦
大塚　浩志
田島　賢一
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三菱電機株式会社
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Priority to JP2018549591A priority Critical patent/JP6472583B1/en
Priority to PCT/JP2018/019362 priority patent/WO2019220637A1/en
Publication of WO2019220637A1 publication Critical patent/WO2019220637A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/59—Responders; Transponders
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
    • H04B5/40—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by components specially adapted for near-field transmission
    • H04B5/48—Transceivers

Definitions

  • the present invention relates to a wireless communication technique for performing data communication by a backscatter (backscatter) modulation method.
  • a data receiver transmits a radio frequency (RF) signal including a carrier component
  • the data transmitter transmits an RF signal received from the data receiver.
  • a modulated wave signal is generated by reflecting and modulating the received RF signal in accordance with a bit string of transmission data to be received and transmitted to the data receiver.
  • the data transmitter transmits the modulated wave signal to the data receiver.
  • the data receiver receives the modulated wave signal from the data transmitter, the data receiver can reconstruct the transmission data by performing demodulation processing and signal processing on the received modulated wave signal.
  • the data transmitter generates a modulated wave signal using the power of the received RF signal, and thus can operate with low power consumption.
  • the modulation of the received RF signal in the data transmitter is based on a digital modulation method such as amplitude-shift keying (ASK) or phase-shift keying (Phase-Shift Keying, PSK). This is done by changing the impedance of the load circuit connected to the output terminal.
  • ASK amplitude-shift keying
  • PSK Phase-shift keying
  • Non-Patent Document 1 discloses a configuration of an RFID tag that performs modulation based on QPSK or quaternary QAM.
  • the RFID tag load circuit includes four reflectors having impedances respectively corresponding to four symbol points in a QPSK or quaternary QAM constellation, and an RF switch circuit that switches the reflectors according to transmission data. Have.
  • the impedance of these reflectors is designed to reflect the received RF signal with different reflection coefficients.
  • Non-Patent Document 1 in order to realize modulation based on QPSK or quaternary QAM (number of symbols: 4), the same number as the number of symbols of the constellation. 4 reflectors and an RF switch circuit for switching these reflectors must be provided. Therefore, in order to realize modulation based on 16-value QAM (number of symbols: 16), it is necessary to provide 16 reflectors and an RF switch circuit for switching these reflectors. Furthermore, 64-value QAM (number of symbols) is required. In order to realize the modulation based on: 64), it is necessary to provide 64 reflectors and an RF switch circuit for switching these reflectors.
  • an object of the present invention is to provide a radio communication apparatus and a radio communication system capable of suppressing an increase in circuit scale accompanying an increase in the number of symbols in a constellation of a multilevel modulation scheme even in a configuration of a backscatter modulation scheme. Is to provide.
  • a wireless communication apparatus distributes power of a high-frequency signal received by an antenna element and supplies a first reception signal and a second reception signal to its own first input / output terminal and second input / output terminal.
  • a modulated wave signal to be transmitted from the antenna element is generated by combining the power of the first reflected signal for the first received signal and the second reflected signal for the second received signal.
  • the first reflected signal by reflecting and modulating the first received signal with a first reflection coefficient determined in accordance with the first variable impedance.
  • the second reflector that generates the second reflected signal, the first control signal that defines the first variable impedance, and the second variable based on a transmission symbol sequence that is generated according to a predetermined multilevel modulation method
  • a load control unit that generates a second control signal for determining impedance.
  • the first reflector includes a first transmission line having one end connected to the first input / output terminal, and a pair of controlled terminals respectively connected to the other end of the first transmission line and a bias voltage source.
  • first transistor having a control terminal for receiving the first control signal
  • the second reflector having one end connected to the second input / output terminal, and the first transmission
  • a second transmission line having an electrical length different from the electrical length of the line, a pair of controlled terminals respectively connected to the other end of the second transmission line and another bias voltage source, and the second transmission line
  • a second transistor having a control terminal for receiving a control signal.
  • FIG. 1 It is a block diagram which shows the structural example of the radio
  • FIG. 6 is a diagram illustrating a configuration example of a second reflector in the first embodiment.
  • FIG. It is a figure which shows schematically the transmission line which has electric length (phi). It is a complex top view which shows the example of the reflection coefficient for implement
  • 4 is a diagram illustrating a configuration example of a first reflector in the first embodiment.
  • FIG. It is a figure which shows the structural example of the 2nd reflector in Embodiment 2.
  • FIG. 1 is a block diagram showing a configuration example of a wireless communication system 1 according to the first embodiment of the present invention.
  • a wireless communication system 1 shown in FIG. 1 includes a wireless communication device 10 that operates as a data reception device, and a wireless communication device 20 that operates as a data transmission device (transponder) in accordance with a backscatter modulation method. Yes.
  • the wireless communication device 10 transmits a radio frequency (RF) signal Cw including a carrier wave component toward the wireless communication device 20.
  • RF radio frequency
  • the wireless communication device 20 responds to the RF signal Cw. That is, the wireless communication device 20 can generate a modulated wave signal Mw including transmission data using the power of the RF signal Cw and transmit the modulated wave signal Mw toward the wireless communication device 10.
  • the wireless communication device 10 operating as a data receiving device includes an antenna element A1, a communication control unit 11, a PLL (Phase Locked Loop) circuit 12, a transmission circuit 13, a directional coupler 14, and a reception circuit. 15 and a demodulator 16.
  • the hardware configuration of the communication control unit 11 and the demodulator 16 is, for example, a semiconductor integrated circuit such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated i Circuit), or FPGA (Field-Programmable Gate Array) or a plurality of semiconductor integrated circuits. It can be realized by a processor.
  • the hardware configuration of the communication control unit 11 and the demodulator 16 may be realized by one or a plurality of processors including an arithmetic device such as a CPU (Central Processing Unit) that executes a program code of software or firmware.
  • a CPU Central Processing Unit
  • the PLL circuit 12 operates under the control of the communication control unit 11 and generates a local signal having a carrier frequency in a high frequency band such as a microwave band or a UHF (Ultra High Frequency) band.
  • the PLL circuit 12 supplies the local signal to the transmission circuit 13 and the reception circuit 15, respectively.
  • the transmission circuit 13 operates under the control of the communication control unit 11 and generates an RF signal Cw for transmission using the local signal. Further, the transmission circuit 13 supplies the RF signal Cw to the antenna element A1 via the directional coupler 14.
  • the directional coupler 14 can be configured using, for example, a known circulator.
  • the wireless communication device 10 When the wireless communication device 10 receives the modulated wave signal Mw from the wireless communication device 20, the modulated wave signal Mw propagates from the antenna element A1 to the receiving circuit 15 via the directional coupler 14.
  • the receiving circuit 15 converts the modulated wave signal Mw into a baseband received signal (in-phase signal and quadrature signal) using the local signal supplied from the PLL circuit 12 according to a known direct conversion method, and these basebands. It can be configured as a circuit for supplying the received signal to the demodulator 16.
  • the demodulator 16 performs digital demodulation on the baseband received signal in accordance with a multi-level modulation method such as quadrature-amplitude modulation (QAM) adopted in the wireless communication system 1, and reconstructs transmission data.
  • QAM quadrature-amplitude modulation
  • the transmission data is supplied to the communication control unit 11.
  • the wireless communication device 20 responds to an RF signal Cw from the wireless communication device 10 and is an individual such as a person, a product, or a logistics material.
  • information for processing encryption information for example, a secret key, a public key, or electronic signature data
  • the communication control unit 11 can use the reconfigured transmission data for various purposes (for example, employee management, product inventory management, individual authentication, or decryption of encrypted information). It is.
  • the wireless communication device 20 that operates as a data transmission device includes an antenna element A2, a power distributor 21, a load control unit 22, a first reflector 23, a second reflector 24, and transmission data.
  • a storage unit 25 and a modulator 26 are provided.
  • the hardware configurations of the load control unit 22 and the modulator 26 can be realized by, for example, one or a plurality of processors having a semiconductor integrated circuit such as a DSP, ASIC, or FPGA.
  • the hardware configuration of the load control unit 22 and the modulator 26 may be realized by one or a plurality of processors including an arithmetic device such as a CPU that executes a program code of software or firmware.
  • the transmission data storage unit 25 includes a nonvolatile memory (not shown) that stores a bit string of the transmission data TD, and a read circuit that outputs the transmission data TD read from the nonvolatile memory to the modulator 26. ing.
  • the power distributor 21 is a high-frequency circuit that distributes power of the RF signal Cw received by the antenna element A2 and outputs two-channel received RF signals Cw1 and Cw2. That is, the power distributor 21 divides the power of the RF signal Cw input from the antenna element A2 into two equal parts, and the received RF signal Cw1 (first received signal) having half the power of the RF signal Cw is self-divided. At the same time, the received RF signal Cw2 (second received signal) having half the power of the RF signal Cw is output from the first input / output terminal of the first input / output terminal. Output to the second reflector 24. The received RF signals Cw1 and Cw2 have the same phase.
  • the first reflector 23 is a load circuit having a variable impedance Z 1 (first variable impedance) determined according to the control signal GC1 (first control signal), and a single control signal that transmits the control signal CG1.
  • the load control unit 22 is connected via a line.
  • the first reflector 23 generates the reflected signal Mw1 (first reflected signal) by reflecting the received RF signal Cw1 with a first reflection coefficient ⁇ 1 determined according to the variable impedance Z 1 and modulating the received RF signal Cw1 in multiple stages. To do.
  • the received RF signal Cw1 is modulated by changing at least one of the amplitude and phase of the received RF signal Cw1.
  • the reflected signal Mw1 propagates from the first reflector 23 to the first input / output terminal of the power distributor 21.
  • the first reflection coefficient ⁇ 1 is a voltage reflection coefficient when the first reflector 23 side is viewed from the first input / output terminal of the power distributor 21.
  • the first reflection coefficient ⁇ 1 is a reflection that returns from the load to the first input / output terminal with respect to the voltage of the received wave (received RF signal Cw1) propagating from the first input / output terminal to the load (first reflector 23). It is defined as the voltage ratio of the wave (reflected signal Mw1). In general, it is known that the voltage reflection coefficient has a one-to-one correspondence with the impedance of the load.
  • Such a first reflection coefficient ⁇ 1 is expressed by the following equation (1), for example.
  • ⁇ 1 is the phase of the first reflection coefficient ⁇ 1
  • ⁇ 1 is the magnitude of the first reflection coefficient ⁇ 1
  • j is an imaginary unit.
  • the second reflector 24 is a load circuit having a variable impedance Z 2 (second variable impedance) determined according to the control signal GC2 (second control signal), and is a single circuit that transmits the control signal GC2.
  • the load control unit 22 is connected via a control signal line.
  • the second reflector 24, generates a reflected signal Mw2 (second reflected signal) by reflects the received RF signal Cw2 second reflection coefficient gamma 2 determined in accordance with the variable impedance Z 2, and is modulated in multiple steps To do.
  • the received RF signal Cw2 is modulated by changing at least one of the amplitude and phase of the received RF signal Cw2.
  • the reflected signal Mw2 propagates from the second reflector 24 to the second input / output terminal of the power distributor 21.
  • the second reflection coefficient ⁇ 2 is a voltage reflection coefficient when the second reflector 24, which is a load, is viewed from the second input / output end of the power distributor 21.
  • the second reflection coefficient ⁇ 2 is a reflected wave returning from the load (second reflector 24) to the second input / output terminal with respect to the voltage of the received wave (received RF signal Cw2) propagating from the second input / output terminal to the load. It is defined as the voltage ratio of (reflected signal Mw2).
  • Such a second reflection coefficient ⁇ 2 is expressed by the following equation (2), for example.
  • ⁇ 2 is the phase of the second reflection coefficient ⁇ 2
  • ⁇ 2 is the magnitude of the second reflection coefficient ⁇ 2 .
  • the power distributor 21 combines the reflected signals Mw1 and Mw2 input from the first reflector 23 and the second reflector 24, respectively, to generate a modulated wave signal Mw.
  • the modulated wave signal Mw is transmitted from the antenna element A2 toward the wireless communication device 10.
  • the combined reflection coefficient ⁇ sum when the power distributor 21 side is viewed from the antenna element A2 is expressed by the following equation (3), for example.
  • Equation (3) Re [ ⁇ sum ] is the real part of the combined reflection coefficient ⁇ sum
  • Im [ ⁇ sum ] is the imaginary part of the combined reflection coefficient ⁇ sum
  • the real part Re [ ⁇ sum ] and the imaginary part Im [ ⁇ sum ] are expressed by the following equations (4) and (5).
  • the first reflection coefficient ⁇ 1 and the second reflection coefficient ⁇ 2 have an orthogonal relationship.
  • the first reflection coefficient ⁇ 1 and the second reflection coefficient ⁇ 2 are expressed by complex numbers
  • the first reflection coefficient ⁇ 1 and the second reflection coefficient ⁇ 2 are orthogonal to each other on the complex plane.
  • FIG. 2 is a complex plan view showing examples of the first reflection coefficient ⁇ 1 , the second reflection coefficient ⁇ 2, and the combined reflection coefficient ⁇ sum .
  • the horizontal axis ⁇ r represents the normalized real part
  • the vertical axis ⁇ i represents the normalized imaginary part.
  • a modulator 26 shown in FIG. 1 generates a transmission symbol sequence by performing primary modulation on a bit sequence (data bit sequence) of transmission data TD in accordance with a constellation of a predetermined multi-level modulation scheme such as multi-level QAM.
  • FIG. 3 is a diagram illustrating an example of a constellation when 16-value QAM (number of symbols: 16) is adopted as the multi-level modulation method.
  • the horizontal axis (I axis) represents the in-phase component
  • the vertical axis (Q axis) represents the quadrature component.
  • the load control unit 22 individually controls the load impedance states of the first reflector 23 and the second reflector 24, so that the load impedance state of the entire set of the first reflector 23 and the second reflector 24 is as follows. It is possible to generate the same number of states as the number of symbols in the constellation of the multi-level modulation system (16 points in the case of 16-level QAM). In other words, the load control unit 22 generates the same number of combined reflection coefficients ⁇ sum as the number of symbols of the constellation by individually controlling the load impedance states of the first reflector 23 and the second reflector 24. Is possible.
  • N reflection coefficient values ⁇ 1,1 ,..., ⁇ 1, N N is an integer of 2 or more
  • the second reflection coefficient ⁇ 2 Assuming that M reflection coefficient values ⁇ 2,1 ,..., ⁇ 2, M (M is an integer equal to or greater than 2) can be set as values, the value of the combined reflection coefficient ⁇ sum is an N ⁇ M pattern.
  • the reflection coefficient value can be set.
  • FIG. 4A and 4B are complex plan views showing examples of the first reflection coefficient ⁇ 1 and the second reflection coefficient ⁇ 2 for realizing 16-value QAM.
  • the first reflection coefficient ⁇ 1 may take any one of four reflection coefficient values ⁇ 1,1 , ⁇ 1,2 , ⁇ 1,3 , ⁇ 1,4.
  • Figure 5 is a data bit value corresponding to each transmission symbol is a diagram showing an example of a correspondence between the first reflection coefficient gamma 1 and the second reflection coefficient gamma 2.
  • FIG. 6 is a diagram illustrating a configuration example of the first reflector 23
  • FIG. 7 is a diagram illustrating a configuration example of the second reflector 24.
  • the first reflector 23 includes a transmission line 33 (first transmission line) having one end connected to the first input / output end of the power distributor 21 and the other end of the transmission line 33. And a field effect transistor 31 connected to the.
  • the transmission line 33 has an electrical length ⁇ (unit: radians) between both ends of the transmission line 33 with reference to the carrier frequency of the RF signal Cw.
  • the field effect transistor 31 includes a gate terminal 31g that is a control terminal that receives the control signal GC1, a drain terminal 31d that is a controlled terminal connected to the other end of the transmission line 33, and a bias voltage source that supplies a DC voltage.
  • This is a variable impedance element having a source terminal 31 s which is a controlled terminal directly connected to 32.
  • the field effect transistor 31 is designed to operate in a linear region in accordance with the voltage of the control signal GC1, that is, the control voltage. Therefore, the load control unit 22 variably controls the impedance (mainly resistance value) of the field effect transistor 31 in multiple stages by supplying a control voltage corresponding to each bit value of the transmission symbol string to the gate terminal 31g. can do.
  • the reflection coefficient when the transmission line 50 side is viewed from one end 50 b of the transmission line 50 is represented by ⁇ b , and transmission is performed from the other end 50 a of the transmission line 50.
  • the line 50 side denote the reflection coefficient when seen opposite side gamma a.
  • the reflection coefficient ⁇ b is generally expressed by the following equation (7) using the absolute value
  • the field effect transistor 31 extends from the reflection surface 1 ⁇ at the position of the drain terminal 31d.
  • the reflection coefficient when viewed from the side is represented by ⁇ 1 ⁇ .
  • the first reflection coefficient ⁇ 1 is expressed by the following equation (8) using the reflection coefficient ⁇ 1 ⁇ .
  • the second reflector 24 includes a transmission line 43 (second transmission line) having one end connected to the second input / output end of the power distributor 21, and the transmission line 43. And a field effect transistor 41 connected to the other end.
  • the transmission line 43 has an electrical length ⁇ + ⁇ / 4 (unit: radians) between both ends of the transmission line 43 with reference to the carrier frequency of the RF signal Cw.
  • the field effect transistor 41 includes a gate terminal 41g that is a control terminal that receives a control signal GC2, a drain terminal 41d that is a controlled terminal connected to the other end of the transmission line 43, and a bias voltage source that supplies a DC voltage.
  • 42 is a variable impedance element having a source terminal 41 s which is a controlled terminal directly connected to 42.
  • the field effect transistor 41 is designed to operate in a linear region according to the voltage of the control signal GC2, that is, the control voltage. Therefore, the load control unit 22 variably controls the impedance (mainly resistance value) of the field effect transistor 41 in multiple stages by supplying a control voltage corresponding to each bit value of the transmission symbol string to the gate terminal 41g. can do.
  • the second reflection coefficient gamma 2 As viewed through the transmission line 43 side from the output end of the second reflector 24 beta, reflection when the reflecting surface 2 ⁇ at the position of the drain terminal 41d viewed field effect transistor 41 side The coefficient is represented by ⁇ 2 ⁇ .
  • the second reflection coefficient ⁇ 2 is expressed by the following equation (9) using the reflection coefficient ⁇ 2 ⁇ .
  • FIG. 9 is a complex plan view showing an example of reflection coefficients ⁇ 1 ⁇ and ⁇ 2 ⁇ for realizing 16-value QAM.
  • four reflection coefficient value gamma l [alpha] as the value of the reflection coefficient ⁇ 1 ⁇ , 1, ..., ⁇ 1 ⁇ , 4 are possible settings, as the value of the second reflection coefficient gamma 2.beta, four of the reflection coefficient value ⁇ 2 ⁇ , 1, ..., ⁇ 2 ⁇ , 4 are possible settings.
  • the relationship between the values ⁇ 2,1 , ⁇ 2,2 , ⁇ 2,3 , ⁇ 2,4 of the reflection coefficient ⁇ 2 can be set as shown in the following equations (11) to (14), for example. is there.
  • FIG. 10 is a diagram illustrating an example of a correspondence relationship among the data bit value, the first reflection coefficient ⁇ 1 , the reflection coefficient ⁇ 1 ⁇ , the second reflection coefficient ⁇ 2, and the reflection coefficient ⁇ 2 ⁇ corresponding to each transmission symbol.
  • the load control unit 22 sets the reflection coefficients ⁇ 1 ⁇ and ⁇ 2 ⁇ using the 16 patterns of FIG. 10 to cause the first reflector 23 and the second reflector 24 to perform modulation based on 16-value QAM. it can.
  • the first reflector 23 includes the transmission line 33 having one end connected to the first input / output end of the power distributor 21 and the transmission line 33.
  • a field effect transistor 31 connected to the other end of the line 33.
  • the field effect transistor 31 includes a gate terminal 31g that receives the control signal GC1; a drain terminal 31d connected to the other end of the transmission line 33; A source terminal 31 s connected to the bias voltage source 32.
  • the second reflector 24 includes a transmission line 43 having one end connected to the second input / output end of the power distributor 21 and an electric field connected to the other end of the transmission line 43.
  • the field effect transistor 41 includes a gate terminal 41 g that receives the control signal GC 2, a drain terminal 41 d connected to the other end of the transmission line 43, and a source terminal connected to the bias voltage source 42. 41s.
  • the electrical lengths of the transmission lines 33 and 43 are set to be different from each other.
  • the load control unit 22 Based on the transmission symbol sequence generated by the modulator 26, the load control unit 22 generates control signals GC1 and GC2 that respectively determine the variable impedances Z 1 and Z 2 of the first reflector 23 and the second reflector 24 in multiple stages. Can be generated. Therefore, even when the number of symbols of the constellation of the multi-level modulation method is large, it is possible to provide the wireless communication device 20 having a small circuit scale.
  • Non-Patent Document 1 requires the same number of reflectors as the number of symbols in the constellation of the multi-level modulation method, and an RF switch circuit for switching these reflectors. Therefore, as the number of symbols in the constellation of the multi-level modulation system increases, the circuit configuration becomes larger.
  • the wireless communication device 20 according to the present embodiment an increase in circuit scale associated with an increase in the number of constellation symbols can be suppressed. Can be manufactured.
  • the transmission line 33 of the first reflector 23 is provided between the drain terminal 31d of the field effect transistor 31 operating as a variable impedance element and the input / output end ⁇ of the first reflector 23 (FIG. 6).
  • the transmission line 43 of the second reflector 24 is provided between the drain terminal 41d of the field effect transistor 41 operating as a variable impedance element and the input / output end ⁇ of the second reflector 24 (FIG. 7). ).
  • the electrical lengths of the transmission lines 33 and 43 are different from each other. For this reason, the load control unit 22 can variably control the load impedance state of the entire set of the first reflector 23 and the second reflector 24 in multiple steps only by using the two control signals GC1 and GC2. it can.
  • FIG. 11 is a block diagram illustrating a configuration example of the wireless communication device 20A according to the second embodiment.
  • a wireless communication device 20A shown in FIG. 11 operates as a data transmission device, and includes an antenna element A2, a power distributor 21, a load control unit 22A, a first reflector 23A, a second reflector 24A, a transmission data storage unit 25, and A modulator 26 is provided.
  • the configuration of the wireless communication device 20A is the same as the configuration of the wireless communication device 20 illustrated in FIG. 1 except for the load control unit 22A, the first reflector 23A, and the second reflector 24A.
  • the first reflector 23A of the present embodiment is a load circuit having a variable impedance Z 1 (first variable impedance) determined according to a control signal BC1 (first control signal), and transmits the control signal BC1. It is connected to the load control unit 22A through a single control signal line. Like the first reflector 23 of the first embodiment, the first reflector 23A may reflects the received RF signal Cw1 in the first reflection coefficient gamma 1 determined in accordance with the variable impedance Z 1, and is modulated in multiple steps Thus, the reflection signal Mw1 (first reflection signal) is generated.
  • FIG. 12 is a diagram illustrating a configuration example of the first reflector 23A.
  • the first reflector 23 ⁇ / b> A includes a transmission line 33 (first transmission line) having one end connected to the first input / output end of the power distributor 21 and the other end of the transmission line 33.
  • a bipolar transistor 61 connected to.
  • the bipolar transistor 61 is directly connected to a base terminal 61b that is a control terminal that receives the control signal BC1, an emitter terminal 61e that is a controlled terminal connected to the other end of the transmission line 33, and a bias voltage source 32A.
  • This is a variable impedance element having a collector terminal 61c which is a controlled terminal.
  • the load control unit 22A increases the impedance (mainly resistance value) of the bipolar transistor 61 by supplying a control signal BC1 corresponding to each bit value of the transmission symbol sequence generated by the modulator 26 to the base terminal 61b. It can be variably controlled in stages.
  • the second reflector 24A is a load circuit having a variable impedance Z 2 (second variable impedance) determined according to the control signal BC2 (second control signal), and is a single circuit that transmits the control signal BC2.
  • the load control unit 22A is connected via a control signal line. Similar to the second reflector 24 of the first embodiment, the second reflector 24A reflects the received RF signal Cw2 with a second reflection coefficient ⁇ 2 determined according to the variable impedance Z 2 and modulates it in multiple steps. Thus, the reflection signal Mw2 (second reflection signal) is generated.
  • FIG. 13 is a diagram illustrating a configuration example of the second reflector 24A.
  • the second reflector 24 ⁇ / b> A includes a transmission line 43 (second transmission line) having one end connected to the second input / output end of the power distributor 21 and the other end of the transmission line 43.
  • a bipolar transistor 71 connected to the.
  • the bipolar transistor 71 is directly connected to a base terminal 71b that is a control terminal that receives the control signal BC2, an emitter terminal 71e that is a controlled terminal connected to the other end of the transmission line 43, and a bias voltage source 42A.
  • This is a variable impedance element having a collector terminal 71c which is a controlled terminal.
  • the load control unit 22A increases the impedance (mainly, the resistance value) of the bipolar transistor 71 by supplying a control signal BC2 corresponding to each bit value of the transmission symbol sequence generated by the modulator 26 to the base terminal 71b. It can be variably controlled in stages.
  • the power distributor 21 combines the reflected signals Mw1 and Mw2 input from the first reflector 23A and the second reflector 24A, respectively, to generate a modulated wave signal Mw.
  • the modulated wave signal Mw is transmitted from the antenna element A2 toward the wireless communication device 10.
  • the bipolar transistor 61 of the first reflector 23A and the bipolar transistor 71 of the second reflector 24A have the same characteristics. Therefore, the reflection coefficient ⁇ 1 ⁇ when viewed from the reflection surface 1 ⁇ at the position of the emitter terminal 61e is the same as the reflection coefficient ⁇ 2 ⁇ when viewed from the reflection surface 2 ⁇ at the position of the emitter terminal 71e.
  • the load control unit 22A sets the reflection coefficients ⁇ 1 ⁇ and ⁇ 2 ⁇ to perform modulation based on a multi-level modulation scheme such as 16-value QAM and the second reflector 23A and the second reflector 23A. It can be performed by the reflector 24A.
  • the first reflector 23A includes the transmission line 33 having one end connected to the first input / output end of the power distributor 21, and the transmission line 33.
  • a bipolar transistor 61 connected to the other end of the line 33.
  • the bipolar transistor 61 includes a base terminal 61b that receives the control signal BC1, an emitter terminal 61e connected to the other end of the transmission line 33, and a bias voltage. And a collector terminal 61c connected to the source 32A.
  • the second reflector 24 ⁇ / b> A includes a transmission line 43 having one end connected to the second input / output end of the power distributor 21 and a bipolar connected to the other end of the transmission line 43.
  • the bipolar transistor 71 includes a base terminal 71b that receives the control signal BC2, an emitter terminal 71e connected to the other end of the transmission line 43, and a collector terminal 71c connected to the bias voltage source 42A. have.
  • the load control unit 22A Based on the transmission symbol sequence generated by the modulator 26, the load control unit 22A generates control signals BC1 and BC2 that determine the variable impedances Z 1 and Z 2 of the first reflector 23A and the second reflector 24A in multiple stages, respectively. Can be generated. Therefore, even when the number of symbols of the constellation of the multilevel modulation system is large, it is possible to provide the radio communication device 20A having a small circuit scale. In addition, since an increase in circuit scale accompanying an increase in the number of constellation symbols can be suppressed, a small RFID tag can be manufactured at a lower cost than a conventional RFID tag.
  • the transmission line 33 of the first reflector 23A is provided between the emitter terminal 61e of the bipolar transistor 61 operating as a variable impedance element and the input / output end ⁇ of the first reflector 23A (FIG. 12).
  • the transmission line 43 of the second reflector 24A is provided between the emitter terminal 71e of the bipolar transistor 71 operating as a variable impedance element and the input / output end ⁇ of the second reflector 24 (FIG. 13).
  • the electrical lengths of the transmission lines 33 and 43 are different from each other. For this reason, the load control unit 22A can variably control the load impedance state of the entire set of the first reflector 23A and the second reflector 24A in multiple stages only by using the two control signals BC1 and BC2. it can.
  • phase of the first reflection coefficient ⁇ 1 and the phase of the second reflection coefficient ⁇ 2 in Embodiments 1 and 2 have an orthogonal relationship, but the present invention is not limited to this. It is only necessary that the phase of the first reflection coefficient ⁇ 1 is different from the phase of the second reflection coefficient ⁇ 2 .
  • the multi-level modulation method adopted in the first and second embodiments is not limited to 16-value QAM.
  • 16-value QAM for example, QPSK (Quadrature Phase Shift Keying), ⁇ / 4 shift QPSK, 64-value QAM, or 256-value QAM may be employed.
  • first and second embodiments can be freely combined, any constituent element of each embodiment can be modified, or any constituent element of each embodiment can be omitted.
  • the wireless communication apparatus and the wireless communication system according to the present invention operate in the backscatter modulation scheme, and can realize a simple and small circuit configuration even if the number of constellations in the multilevel modulation scheme is large. It is suitable for a small and lightweight data transmission device that operates with low power consumption, such as an RFID tag.

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Abstract

This wireless communication device (20) comprises: a first reflector (23) which generates a first reflected signal (Mw1) by reflecting and modulating a first received signal (Cw1) at a first reflection coefficient (Γ1); a second reflector (24) which generates a second reflected signal (Mw2) by reflecting and modulating a second received signal (Cw2) at a second reflection coefficient (Γ2); and a load control unit (22) which, on the basis of a transmission symbol string, generates a control signal (GC1) determining the variable impedance of the first reflector (23) and a control signal (GC2) determining the variable impedance of the second reflector (24). The first reflector (23) and the second reflector (24) each include a transmission line and a transistor. Said transistor has: a pair of to-be-controlled terminals that are respectively connected to said transmission line and a bias voltage source; and a control terminal having a control signal (GC1 or GC2) as an input.

Description

無線通信装置および無線通信システムWireless communication apparatus and wireless communication system
　本発明は、バックスキャッタ（後方散乱）変調方式によりデータ通信を行う無線通信技術に関する。 The present invention relates to a wireless communication technique for performing data communication by a backscatter (backscatter) modulation method.
　バックスキャッタ変調（ｂａｃｋｓｃａｔｔｅｒ　ｍｏｄｕｌａｔｉｏｎ）方式を採用する無線通信システムでは、データ受信機が搬送波成分を含む高周波（Ｒａｄｉｏ　Ｆｒｅｑｕｅｎｃｙ，ＲＦ）信号を送信すると、データ送信機は、データ受信機から到来したＲＦ信号を受信し、データ受信機に送信すべき送信データのビット列に応じて、当該受信ＲＦ信号を反射かつ変調することによって変調波信号を生成する。データ送信機は、その変調波信号をデータ受信機に送信する。データ受信機は、データ送信機から変調波信号を受信すると、当該受信された変調波信号に復調処理および信号処理を施すことで送信データを再構成することができる。このようにデータ送信機は、受信ＲＦ信号の電力を利用して変調波信号を生成するので、低消費電力で動作することができる。ここで、データ送信機における受信ＲＦ信号の変調は、振幅偏移変調（Ａｍｐｌｉｔｕｄｅ－Ｓｈｉｆｔ　Ｋｅｙｉｎｇ，ＡＳＫ）または位相偏移変調（Ｐｈａｓｅ－Ｓｈｉｆｔ　Ｋｅｙｉｎｇ，ＰＳＫ）などのディジタル変調方式に基づき、アンテナの入出力端に接続された負荷回路のインピーダンスを変化させることによって行われる。 In a wireless communication system employing a backscatter modulation method, when a data receiver transmits a radio frequency (RF) signal including a carrier component, the data transmitter transmits an RF signal received from the data receiver. A modulated wave signal is generated by reflecting and modulating the received RF signal in accordance with a bit string of transmission data to be received and transmitted to the data receiver. The data transmitter transmits the modulated wave signal to the data receiver. When the data receiver receives the modulated wave signal from the data transmitter, the data receiver can reconstruct the transmission data by performing demodulation processing and signal processing on the received modulated wave signal. As described above, the data transmitter generates a modulated wave signal using the power of the received RF signal, and thus can operate with low power consumption. Here, the modulation of the received RF signal in the data transmitter is based on a digital modulation method such as amplitude-shift keying (ASK) or phase-shift keying (Phase-Shift Keying, PSK). This is done by changing the impedance of the load circuit connected to the output terminal.
　このようなバックスキャッタ変調方式は、ＲＦタグあるいはＲＦＩＤタグと呼ばれる無線通信機の通信方式として広く採用されている。たとえば、下記の非特許文献１には、ＱＰＳＫまたは４値ＱＡＭに基づいた変調を行うＲＦＩＤタグの構成が開示されている。このＲＦＩＤタグの負荷回路は、ＱＰＳＫまたは４値ＱＡＭのコンステレーションにおける４個のシンボル点にそれぞれ対応するインピーダンスを有する４個の反射器と、送信データに応じて反射器を切り替えるＲＦスイッチ回路とを有する。それら反射器のインピーダンスは、互いに異なる反射係数で受信ＲＦ信号を反射させるように設計される。 Such a backscatter modulation method is widely adopted as a communication method of a wireless communication device called an RF tag or an RFID tag. For example, the following Non-Patent Document 1 discloses a configuration of an RFID tag that performs modulation based on QPSK or quaternary QAM. The RFID tag load circuit includes four reflectors having impedances respectively corresponding to four symbol points in a QPSK or quaternary QAM constellation, and an RF switch circuit that switches the reflectors according to transmission data. Have. The impedance of these reflectors is designed to reflect the received RF signal with different reflection coefficients.
　上記のとおり、非特許文献１に開示されている無線通信機（ＲＦＩＤタグ）では、ＱＰＳＫまたは４値ＱＡＭ（シンボル数：４）に基づく変調を実現するために、当該コンステレーションのシンボル数と同数の４個の反射器と、これら反射器を切り替えるＲＦスイッチ回路とを設ける必要がある。このため、１６値ＱＡＭ（シンボル数：１６）に基づく変調を実現するには、１６個の反射器とこれら反射器を切り替えるＲＦスイッチ回路とを設ける必要があり、さらに、６４値ＱＡＭ（シンボル数：６４）に基づく変調を実現するには、６４個の反射器とこれら反射器を切り替えるＲＦスイッチ回路とを設ける必要がある。しかしながら、そのように多値変調方式のコンステレーションのシンボル数と同数の反射器と、これら反射器を切り替えるＲＦスイッチ回路とを必要とするＲＦＩＤタグでは、その回路構成が大規模化し、消費電力の増大と製造コストの増大を招くという課題がある。 As described above, in the wireless communication device (RFID tag) disclosed in Non-Patent Document 1, in order to realize modulation based on QPSK or quaternary QAM (number of symbols: 4), the same number as the number of symbols of the constellation. 4 reflectors and an RF switch circuit for switching these reflectors must be provided. Therefore, in order to realize modulation based on 16-value QAM (number of symbols: 16), it is necessary to provide 16 reflectors and an RF switch circuit for switching these reflectors. Furthermore, 64-value QAM (number of symbols) is required. In order to realize the modulation based on: 64), it is necessary to provide 64 reflectors and an RF switch circuit for switching these reflectors. However, in an RFID tag that requires the same number of reflectors as the number of symbols in the constellation of the multi-level modulation method and an RF switch circuit that switches these reflectors, the circuit configuration becomes large and power consumption is reduced. There is a problem of increasing the manufacturing cost.
　上記に鑑みて本発明の目的は、バックスキャッタ変調方式の構成でも、多値変調方式のコンステレーションのシンボル数増大に伴う回路規模の増大を抑制することを可能とする無線通信装置および無線通信システムを提供することである。 In view of the above, an object of the present invention is to provide a radio communication apparatus and a radio communication system capable of suppressing an increase in circuit scale accompanying an increase in the number of symbols in a constellation of a multilevel modulation scheme even in a configuration of a backscatter modulation scheme. Is to provide.
　本発明の一態様による無線通信装置は、アンテナ素子で受信された高周波信号を電力分配して第１の受信信号および第２の受信信号を自己の第１の入出力端および第２の入出力端からそれぞれ出力し、前記第１の受信信号に対する第１の反射信号と前記第２の受信信号に対する第２の反射信号とを電力合成して前記アンテナ素子から送信されるべき変調波信号を生成する電力分配器と、第１の可変インピーダンスを有し、前記第１の可変インピーダンスに応じて定まる第１反射係数で前記第１の受信信号を反射かつ変調させることによって前記第１の反射信号を生成する第１反射器と、第２の可変インピーダンスを有し、前記第２の可変インピーダンスに応じて定まる第２反射係数で前記第２の受信信号を反射かつ変調させることによって前記第２の反射信号を生成する第２反射器と、所定の多値変調方式に従って生成された送信シンボル列に基づき、前記第１の可変インピーダンスを定める第１の制御信号と前記第２の可変インピーダンスを定める第２の制御信号とを生成する負荷制御部とを備える。前記第１反射器は、前記第１の入出力端に一端が接続された第１の伝送線路と、前記第１の伝送線路の他端およびバイアス電圧源にそれぞれ接続された一対の被制御端子を有するとともに前記第１の制御信号を入力とする制御端子を有する第１のトランジスタとを含み、前記第２反射器は、前記第２の入出力端に一端が接続され、前記第１の伝送線路の電気長とは異なる電気長を有する第２の伝送線路と、前記第２の伝送線路の他端および他のバイアス電圧源にそれぞれ接続された一対の被制御端子を有するとともに前記第２の制御信号を入力とする制御端子を有する第２のトランジスタとを含む。 A wireless communication apparatus according to an aspect of the present invention distributes power of a high-frequency signal received by an antenna element and supplies a first reception signal and a second reception signal to its own first input / output terminal and second input / output terminal. A modulated wave signal to be transmitted from the antenna element is generated by combining the power of the first reflected signal for the first received signal and the second reflected signal for the second received signal. The first reflected signal by reflecting and modulating the first received signal with a first reflection coefficient determined in accordance with the first variable impedance. A first reflector to be generated, and a second variable impedance, wherein the second received signal is reflected and modulated by a second reflection coefficient determined according to the second variable impedance. The second reflector that generates the second reflected signal, the first control signal that defines the first variable impedance, and the second variable based on a transmission symbol sequence that is generated according to a predetermined multilevel modulation method A load control unit that generates a second control signal for determining impedance. The first reflector includes a first transmission line having one end connected to the first input / output terminal, and a pair of controlled terminals respectively connected to the other end of the first transmission line and a bias voltage source. And a first transistor having a control terminal for receiving the first control signal, the second reflector having one end connected to the second input / output terminal, and the first transmission A second transmission line having an electrical length different from the electrical length of the line, a pair of controlled terminals respectively connected to the other end of the second transmission line and another bias voltage source, and the second transmission line And a second transistor having a control terminal for receiving a control signal.
　本発明によれば、多値変調方式のコンステレーションのシンボル数増大に伴う回路規模の増大を抑制することができる。 According to the present invention, it is possible to suppress an increase in circuit scale accompanying an increase in the number of symbols in a constellation of a multilevel modulation system.
本発明に係る実施の形態１である無線通信システムの構成例を示すブロック図である。It is a block diagram which shows the structural example of the radio | wireless communications system which is Embodiment 1 which concerns on this invention. 第１反射係数，第２反射係数および合成反射係数の例を示す複素平面図である。It is a complex plan view showing an example of the first reflection coefficient, the second reflection coefficient, and the combined reflection coefficient. １６値ＱＡＭのコンステレーションのシンボル点を示す図である。It is a figure which shows the symbol point of the constellation of 16 value QAM. 図４Ａおよび図４Ｂは、１６値ＱＡＭを実現するための第１反射係数と第２反射係数の例を示す複素平面図である。4A and 4B are complex plan views illustrating examples of the first reflection coefficient and the second reflection coefficient for realizing 16-value QAM. 各送信シンボルに対応するデータビット値、第１反射係数および第２反射係数の間の対応関係の例を示す図である。It is a figure which shows the example of the correspondence between the data bit value corresponding to each transmission symbol, a 1st reflection coefficient, and a 2nd reflection coefficient. 実施の形態１における第１反射器の構成例を示す図である。4 is a diagram illustrating a configuration example of a first reflector in the first embodiment. FIG. 実施の形態１における第２反射器の構成例を示す図である。6 is a diagram illustrating a configuration example of a second reflector in the first embodiment. FIG. 電気長φを有する伝送線路を概略的に示す図である。It is a figure which shows schematically the transmission line which has electric length (phi). １６値ＱＡＭを実現するための反射係数の例を示す複素平面図である。It is a complex top view which shows the example of the reflection coefficient for implement | achieving 16 value QAM. 各送信シンボルに対応するデータビット値と各種反射係数との間の対応関係の例を示す図である。It is a figure which shows the example of the correspondence between the data bit value corresponding to each transmission symbol, and various reflection coefficients. 本発明に係る実施の形態２における無線通信装置の構成例を示すブロック図である。It is a block diagram which shows the structural example of the radio | wireless communication apparatus in Embodiment 2 which concerns on this invention. 実施の形態１における第１反射器の構成例を示す図である。4 is a diagram illustrating a configuration example of a first reflector in the first embodiment. FIG. 実施の形態２における第２反射器の構成例を示す図である。It is a figure which shows the structural example of the 2nd reflector in Embodiment 2. FIG.
　以下、図面を参照しつつ、本発明に係る実施の形態について詳細に説明する。なお、図面全体において同一符号を付された構成要素は、同一構成および同一機能を有するものとする。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the component to which the same code | symbol was attached | subjected in the whole drawing shall have the same structure and the same function.
実施の形態１．
　図１は、本発明に係る実施の形態１である無線通信システム１の構成例を示すブロック図である。図１に示される無線通信システム１は、データ受信装置として動作する無線通信装置１０と、バックスキャッタ変調（ｂａｃｋｓｃａｔｔｅｒ　ｍｏｄｕｌａｔｉｏｎ）方式に従ってデータ送信装置（トランスポンダ）として動作する無線通信装置２０とで構成されている。無線通信装置１０は、搬送波成分を含む高周波（ＲＦ）信号Ｃｗを無線通信装置２０に向けて送信する。無線通信装置２０は、無線通信装置１０からＲＦ信号Ｃｗを受信すると、当該ＲＦ信号Ｃｗに応答する。すなわち、無線通信装置２０は、ＲＦ信号Ｃｗの電力を利用して送信データを含む変調波信号Ｍｗを生成し、当該変調波信号Ｍｗを無線通信装置１０に向けて送信することができる。 Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration example of a wireless communication system 1 according to the first embodiment of the present invention. A wireless communication system 1 shown in FIG. 1 includes a wireless communication device 10 that operates as a data reception device, and a wireless communication device 20 that operates as a data transmission device (transponder) in accordance with a backscatter modulation method. Yes. The wireless communication device 10 transmits a radio frequency (RF) signal Cw including a carrier wave component toward the wireless communication device 20. When receiving the RF signal Cw from the wireless communication device 10, the wireless communication device 20 responds to the RF signal Cw. That is, the wireless communication device 20 can generate a modulated wave signal Mw including transmission data using the power of the RF signal Cw and transmit the modulated wave signal Mw toward the wireless communication device 10.
　データ受信装置として動作する無線通信装置１０は、図１に示されるように、アンテナ素子Ａ１、通信制御部１１、ＰＬＬ（Ｐｈａｓｅ　Ｌｏｃｋｅｄ　Ｌｏｏｐ）回路１２、送信回路１３、方向性結合器１４、受信回路１５および復調器１６を備えている。通信制御部１１および復調器１６のハードウェア構成は、たとえば、ＤＳＰ（Ｄｉｇｉｔａｌ　Ｓｉｇｎａｌ　Ｐｒｏｃｅｓｓｏｒ），ＡＳＩＣ（Ａｐｐｌｉｃａｔｉｏｎ  Ｓｐｅｃｉｆｉｃ  Ｉｎｔｅｇｒａｔｅｄ  Ｃｉｒｃｕｉｔ）またはＦＰＧＡ（Ｆｉｅｌｄ－Ｐｒｏｇｒａｍｍａｂｌｅ　Ｇａｔｅ　Ａｒｒａｙ）などの半導体集積回路を有する単数または複数のプロセッサで実現可能である。あるいは、通信制御部１１および復調器１６のハードウェア構成は、ソフトウェアまたはファームウェアのプログラムコードを実行する、ＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）などの演算装置を含む単数または複数のプロセッサで実現されてもよい。 As shown in FIG. 1, the wireless communication device 10 operating as a data receiving device includes an antenna element A1, a communication control unit 11, a PLL (Phase Locked Loop) circuit 12, a transmission circuit 13, a directional coupler 14, and a reception circuit. 15 and a demodulator 16. The hardware configuration of the communication control unit 11 and the demodulator 16 is, for example, a semiconductor integrated circuit such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated ｉ Circuit), or FPGA (Field-Programmable Gate Array) or a plurality of semiconductor integrated circuits. It can be realized by a processor. Alternatively, the hardware configuration of the communication control unit 11 and the demodulator 16 may be realized by one or a plurality of processors including an arithmetic device such as a CPU (Central Processing Unit) that executes a program code of software or firmware.
　ＰＬＬ回路１２は、通信制御部１１による制御を受けて動作し、マイクロ波帯またはＵＨＦ（Ｕｌｔｒａ　Ｈｉｇｈ　Ｆｒｅｑｕｅｎｃｙ）帯などの高周波帯における搬送波周波数を有する局部信号を生成する。ＰＬＬ回路１２は、当該局部信号を送信回路１３と受信回路１５とにそれぞれ供給する。送信回路１３は、通信制御部１１による制御を受けて動作し、当該局部信号を用いて送信用のＲＦ信号Ｃｗを生成する。また、送信回路１３は、当該ＲＦ信号Ｃｗを方向性結合器１４を介してアンテナ素子Ａ１に供給する。方向性結合器１４は、たとえば、公知のサーキュレータを用いて構成可能である。 The PLL circuit 12 operates under the control of the communication control unit 11 and generates a local signal having a carrier frequency in a high frequency band such as a microwave band or a UHF (Ultra High Frequency) band. The PLL circuit 12 supplies the local signal to the transmission circuit 13 and the reception circuit 15, respectively. The transmission circuit 13 operates under the control of the communication control unit 11 and generates an RF signal Cw for transmission using the local signal. Further, the transmission circuit 13 supplies the RF signal Cw to the antenna element A1 via the directional coupler 14. The directional coupler 14 can be configured using, for example, a known circulator.
　無線通信装置１０が無線通信装置２０から変調波信号Ｍｗを受信すると、変調波信号Ｍｗは、アンテナ素子Ａ１から方向性結合器１４を介して受信回路１５に伝播する。たとえば、受信回路１５は、公知のダイレクトコンバージョン方式に従い、ＰＬＬ回路１２から供給された局部信号を用いて変調波信号Ｍｗをベースバンド受信信号（同相信号と直交信号）に変換し、これらベースバンド受信信号を復調器１６に供給する回路として構成可能である。復調器１６は、無線通信システム１で採用されている直交振幅変調（Ｑｕａｄｒａｔｕｒｅ－Ａｍｐｌｉｔｕｄｅ　Ｍｏｄｕｌａｔｉｏｎ，ＱＡＭ）などの多値変調方式に従い、ベースバンド受信信号にディジタル復調を施して送信データを再構成し、当該送信データを通信制御部１１に供給する。たとえば、無線通信システム１がＲＦＩＤシステム（Ｒａｄｉｏ　Ｆｒｅｑｕｅｎｃｙ　ＩＤｅｎｔｉｆｉｃａｔｉｏｎ　ｓｙｓｔｅｍ）に適用される場合、無線通信装置２０は、無線通信装置１０からのＲＦ信号Ｃｗに応答して、人，商品もしくは物流資材などの個体を表す識別情報、または、暗号化情報を処理するための情報（たとえば、秘密鍵，公開鍵もしくは電子署名データ）を送信データとして送信することができる。無線通信装置１０では、通信制御部１１は、再構成された送信データを、各種目的（たとえば、社員管理、商品の在庫管理、個体認証もしくは暗号化情報の復号）のために使用することが可能である。 When the wireless communication device 10 receives the modulated wave signal Mw from the wireless communication device 20, the modulated wave signal Mw propagates from the antenna element A1 to the receiving circuit 15 via the directional coupler 14. For example, the receiving circuit 15 converts the modulated wave signal Mw into a baseband received signal (in-phase signal and quadrature signal) using the local signal supplied from the PLL circuit 12 according to a known direct conversion method, and these basebands. It can be configured as a circuit for supplying the received signal to the demodulator 16. The demodulator 16 performs digital demodulation on the baseband received signal in accordance with a multi-level modulation method such as quadrature-amplitude modulation (QAM) adopted in the wireless communication system 1, and reconstructs transmission data. The transmission data is supplied to the communication control unit 11. For example, when the wireless communication system 1 is applied to an RFID system (Radio Frequency IDentification system), the wireless communication device 20 responds to an RF signal Cw from the wireless communication device 10 and is an individual such as a person, a product, or a logistics material. Or information for processing encryption information (for example, a secret key, a public key, or electronic signature data) can be transmitted as transmission data. In the wireless communication apparatus 10, the communication control unit 11 can use the reconfigured transmission data for various purposes (for example, employee management, product inventory management, individual authentication, or decryption of encrypted information). It is.
　一方、データ送信装置として動作する無線通信装置２０は、図１に示されるように、アンテナ素子Ａ２、電力分配器２１、負荷制御部２２、第１反射器２３、第２反射器２４、送信データ記憶部２５および変調器２６を備えている。負荷制御部２２および変調器２６のハードウェア構成は、たとえば、ＤＳＰ，ＡＳＩＣまたはＦＰＧＡなどの半導体集積回路を有する単数または複数のプロセッサによって実現可能である。あるいは、負荷制御部２２および変調器２６のハードウェア構成は、ソフトウェアまたはファームウェアのプログラムコードを実行する、ＣＰＵなどの演算装置を含む単数または複数のプロセッサで実現されてもよい。送信データ記憶部２５は、送信データＴＤのビット列を記憶する不揮発性メモリ（図示せず）と、当該不揮発性メモリから読み出された送信データＴＤを変調器２６に出力する読み出し回路とで構成されている。 On the other hand, as shown in FIG. 1, the wireless communication device 20 that operates as a data transmission device includes an antenna element A2, a power distributor 21, a load control unit 22, a first reflector 23, a second reflector 24, and transmission data. A storage unit 25 and a modulator 26 are provided. The hardware configurations of the load control unit 22 and the modulator 26 can be realized by, for example, one or a plurality of processors having a semiconductor integrated circuit such as a DSP, ASIC, or FPGA. Alternatively, the hardware configuration of the load control unit 22 and the modulator 26 may be realized by one or a plurality of processors including an arithmetic device such as a CPU that executes a program code of software or firmware. The transmission data storage unit 25 includes a nonvolatile memory (not shown) that stores a bit string of the transmission data TD, and a read circuit that outputs the transmission data TD read from the nonvolatile memory to the modulator 26. ing.
　電力分配器２１は、アンテナ素子Ａ２で受信されたＲＦ信号Ｃｗを電力分配して２チャンネルの受信ＲＦ信号Ｃｗ１，Ｃｗ２を出力する高周波回路である。すなわち、電力分配器２１は、アンテナ素子Ａ２から入力されたＲＦ信号Ｃｗの電力を２等分し、ＲＦ信号Ｃｗの電力の半分の電力を有する受信ＲＦ信号Ｃｗ１（第１の受信信号）を自己の第１の入出力端から第１反射器２３に出力すると同時に、ＲＦ信号Ｃｗの電力の半分の電力を有する受信ＲＦ信号Ｃｗ２（第２の受信信号）を自己の第２の入出力端から第２反射器２４に出力する。受信ＲＦ信号Ｃｗ１，Ｃｗ２の位相は互いに同相である。 The power distributor 21 is a high-frequency circuit that distributes power of the RF signal Cw received by the antenna element A2 and outputs two-channel received RF signals Cw1 and Cw2. That is, the power distributor 21 divides the power of the RF signal Cw input from the antenna element A2 into two equal parts, and the received RF signal Cw1 (first received signal) having half the power of the RF signal Cw is self-divided. At the same time, the received RF signal Cw2 (second received signal) having half the power of the RF signal Cw is output from the first input / output terminal of the first input / output terminal. Output to the second reflector 24. The received RF signals Cw1 and Cw2 have the same phase.
　第１反射器２３は、制御信号ＧＣ１（第１の制御信号）に応じて定まる可変インピーダンスＺ１（第１の可変インピーダンス）を有する負荷回路であり、制御信号ＣＧ１を伝達する単一の制御信号線を介して負荷制御部２２と接続されている。第１反射器２３は、可変インピーダンスＺ１に応じて定まる第１反射係数Γ１で受信ＲＦ信号Ｃｗ１を反射させ、かつ多段階で変調させることによって反射信号Ｍｗ１（第１の反射信号）を生成する。受信ＲＦ信号Ｃｗ１の変調は、受信ＲＦ信号Ｃｗ１の振幅および位相の少なくとも一方を変化させることによって行われる。反射信号Ｍｗ１は、第１反射器２３から電力分配器２１の第１の入出力端に伝播する。 The first reflector 23 is a load circuit having a variable impedance Z 1 (first variable impedance) determined according to the control signal GC1 (first control signal), and a single control signal that transmits the control signal CG1. The load control unit 22 is connected via a line. The first reflector 23 generates the reflected signal Mw1 (first reflected signal) by reflecting the received RF signal Cw1 with a first reflection coefficient Γ 1 determined according to the variable impedance Z 1 and modulating the received RF signal Cw1 in multiple stages. To do. The received RF signal Cw1 is modulated by changing at least one of the amplitude and phase of the received RF signal Cw1. The reflected signal Mw1 propagates from the first reflector 23 to the first input / output terminal of the power distributor 21.
　第１反射係数Γ１は、電力分配器２１の第１の入出力端から第１反射器２３側をみたときの電圧反射係数である。第１反射係数Γ１は、第１の入出力端から負荷（第１反射器２３）へ伝播する受信波（受信ＲＦ信号Ｃｗ１）の電圧に対する、当該負荷から第１の入出力端へ戻る反射波（反射信号Ｍｗ１）の電圧の比率として定義される。一般に、電圧反射係数は、負荷のインピーダンスと一対一で対応することが知られている。 The first reflection coefficient Γ 1 is a voltage reflection coefficient when the first reflector 23 side is viewed from the first input / output terminal of the power distributor 21. The first reflection coefficient Γ 1 is a reflection that returns from the load to the first input / output terminal with respect to the voltage of the received wave (received RF signal Cw1) propagating from the first input / output terminal to the load (first reflector 23). It is defined as the voltage ratio of the wave (reflected signal Mw1). In general, it is known that the voltage reflection coefficient has a one-to-one correspondence with the impedance of the load.
　このような第１反射係数Γ１は、たとえば、次式（１）で表される。

Figure JPOXMLDOC01-appb-I000001
　ここで、θ１は、第１反射係数Γ１の位相、γ１は、第１反射係数Γ１の大きさ、ｊは、虚数単位である。 Such a first reflection coefficient Γ 1 is expressed by the following equation (1), for example.

Figure JPOXMLDOC01-appb-I000001
Here, θ 1 is the phase of the first reflection coefficient Γ 1 , γ 1 is the magnitude of the first reflection coefficient Γ 1 , and j is an imaginary unit.
　一方、第２反射器２４は、制御信号ＧＣ２（第２の制御信号）に応じて定まる可変インピーダンスＺ２（第２の可変インピーダンス）を有する負荷回路であり、制御信号ＧＣ２を伝達する単一の制御信号線を介して負荷制御部２２と接続されている。第２反射器２４は、可変インピーダンスＺ２に応じて定まる第２反射係数Γ２で受信ＲＦ信号Ｃｗ２を反射させ、かつ多段階で変調させることによって反射信号Ｍｗ２（第２の反射信号）を生成する。受信ＲＦ信号Ｃｗ２の変調は、受信ＲＦ信号Ｃｗ２の振幅および位相のうちの少なくとも一方を変化させることによって行われる。反射信号Ｍｗ２は、第２反射器２４から電力分配器２１の第２の入出力端に伝播する。 On the other hand, the second reflector 24 is a load circuit having a variable impedance Z 2 (second variable impedance) determined according to the control signal GC2 (second control signal), and is a single circuit that transmits the control signal GC2. The load control unit 22 is connected via a control signal line. The second reflector 24, generates a reflected signal Mw2 (second reflected signal) by reflects the received RF signal Cw2 second reflection coefficient gamma 2 determined in accordance with the variable impedance Z 2, and is modulated in multiple steps To do. The received RF signal Cw2 is modulated by changing at least one of the amplitude and phase of the received RF signal Cw2. The reflected signal Mw2 propagates from the second reflector 24 to the second input / output terminal of the power distributor 21.
　第１反射係数Γ１と同様に、第２反射係数Γ２は、電力分配器２１の第２の入出力端から、負荷である第２反射器２４側をみたときの電圧反射係数である。第２反射係数Γ２は、第２の入出力端から負荷へ伝播する受信波（受信ＲＦ信号Ｃｗ２）の電圧に対する、負荷（第２反射器２４）から第２の入出力端へ戻る反射波（反射信号Ｍｗ２）の電圧の比率として定義される。 Similar to the first reflection coefficient Γ 1 , the second reflection coefficient Γ 2 is a voltage reflection coefficient when the second reflector 24, which is a load, is viewed from the second input / output end of the power distributor 21. The second reflection coefficient Γ 2 is a reflected wave returning from the load (second reflector 24) to the second input / output terminal with respect to the voltage of the received wave (received RF signal Cw2) propagating from the second input / output terminal to the load. It is defined as the voltage ratio of (reflected signal Mw2).
　このような第２反射係数Γ２は、たとえば、次式（２）で表される。

Figure JPOXMLDOC01-appb-I000002
　ここで、θ２は、第２反射係数Γ２の位相、γ２は、第２反射係数Γ２の大きさである。 Such a second reflection coefficient Γ 2 is expressed by the following equation (2), for example.

Figure JPOXMLDOC01-appb-I000002
Here, θ 2 is the phase of the second reflection coefficient Γ 2 , and γ 2 is the magnitude of the second reflection coefficient Γ 2 .
　電力分配器２１は、第１反射器２３および第２反射器２４からそれぞれ入力された反射信号Ｍｗ１，Ｍｗ２を電力合成して変調波信号Ｍｗを生成する。変調波信号Ｍｗは、アンテナ素子Ａ２から無線通信装置１０に向けて送信される。 The power distributor 21 combines the reflected signals Mw1 and Mw2 input from the first reflector 23 and the second reflector 24, respectively, to generate a modulated wave signal Mw. The modulated wave signal Mw is transmitted from the antenna element A2 toward the wireless communication device 10.
　アンテナ素子Ａ２から電力分配器２１側をみたときの合成反射係数Γｓｕｍは、たとえば、次式（３）で表される。

Figure JPOXMLDOC01-appb-I000003
The combined reflection coefficient Γ sum when the power distributor 21 side is viewed from the antenna element A2 is expressed by the following equation (3), for example.

Figure JPOXMLDOC01-appb-I000003
　式（３）において、Ｒｅ［Γｓｕｍ］は、合成反射係数Γｓｕｍの実数部であり、Ｉｍ［Γｓｕｍ］は、合成反射係数Γｓｕｍの虚数部である。実数部Ｒｅ［Γｓｕｍ］と虚数部Ｉｍ［Γｓｕｍ］は、次式（４），（５）で表される。

Figure JPOXMLDOC01-appb-I000004
In Equation (3), Re [Γ sum ] is the real part of the combined reflection coefficient Γ sum , and Im [Γ sum ] is the imaginary part of the combined reflection coefficient Γ sum . The real part Re [Γ sum ] and the imaginary part Im [Γ sum ] are expressed by the following equations (4) and (5).

Figure JPOXMLDOC01-appb-I000004
　本実施の形態では、第１反射係数Γ１と第２反射係数Γ２とは直交関係を有する。言い換えれば、第１反射係数Γ１と第２反射係数Γ２とが複素数で表現されるとき、第１反射係数Γ１と第２反射係数Γ２とは複素平面上で互いに直交する。図２は、第１反射係数Γ１，第２反射係数Γ２および合成反射係数Γｓｕｍの例を示す複素平面図である。図２において、横軸Γｒは、正規化された実数部を表し、縦軸Γｉは、正規化された虚数部を表している。 In the present embodiment, the first reflection coefficient Γ 1 and the second reflection coefficient Γ 2 have an orthogonal relationship. In other words, when the first reflection coefficient Γ 1 and the second reflection coefficient Γ 2 are expressed by complex numbers, the first reflection coefficient Γ 1 and the second reflection coefficient Γ 2 are orthogonal to each other on the complex plane. FIG. 2 is a complex plan view showing examples of the first reflection coefficient Γ 1 , the second reflection coefficient Γ 2, and the combined reflection coefficient Γ sum . In FIG. 2, the horizontal axis Γr represents the normalized real part, and the vertical axis Γi represents the normalized imaginary part.
　第１反射係数Γ１と第２反射係数Γ２との直交関係の例として、θ１＝０、θ２－θ１＝π／２（９０°）の場合が考えられる。この場合の合成反射係数Γｓｕｍは、次式（６）で表される。

Figure JPOXMLDOC01-appb-I000005
As an example of the orthogonal relationship between the first reflection coefficient Γ 1 and the second reflection coefficient Γ 2 , a case where θ 1 = 0 and θ 2 −θ 1 = π / 2 (90 °) can be considered. The combined reflection coefficient Γ sum in this case is expressed by the following equation (6).

Figure JPOXMLDOC01-appb-I000005
　図１に示される変調器２６は、多値ＱＡＭなどの所定の多値変調方式のコンステレーションに従い、送信データＴＤのビット列（データビット列）に一次変調を施して送信シンボル列を生成するディジタル変調回路である。図３は、多値変調方式として１６値ＱＡＭ（シンボル数：１６）が採用された場合のコンステレーション（ｃｏｎｓｔｅｌｌａｔｉｏｎ）の例を示す図である。図３において、横軸（Ｉ軸）は同相成分を、縦軸（Ｑ軸）は直交位相成分をそれぞれ表している。図３に示されるコンステレーションは、４×４点（＝１６点）の送信シンボルからなる（１送信シンボル当たり４ビット）。 A modulator 26 shown in FIG. 1 generates a transmission symbol sequence by performing primary modulation on a bit sequence (data bit sequence) of transmission data TD in accordance with a constellation of a predetermined multi-level modulation scheme such as multi-level QAM. It is. FIG. 3 is a diagram illustrating an example of a constellation when 16-value QAM (number of symbols: 16) is adopted as the multi-level modulation method. In FIG. 3, the horizontal axis (I axis) represents the in-phase component, and the vertical axis (Q axis) represents the quadrature component. The constellation shown in FIG. 3 includes 4 × 4 points (= 16 points) of transmission symbols (4 bits per transmission symbol).
　負荷制御部２２は、第１反射器２３および第２反射器２４の負荷インピーダンス状態を個別に制御することにより、第１反射器２３と第２反射器２４との組全体の負荷インピーダンス状態として、多値変調方式のコンステレーションのシンボル数（１６値ＱＡＭの場合は１６点）と同数の状態を発生させることができる。言い換えれば、負荷制御部２２は、第１反射器２３および第２反射器２４の負荷インピーダンス状態を個別に制御することにより、当該コンステレーションのシンボル数と同数の合成反射係数Γｓｕｍを発生させることが可能である。たとえば、第１反射係数Γ１の値として、Ｎ個の反射係数値Γ１，１、…、Γ１，Ｎ（Ｎは２以上の整数）が設定可能であり、第２反射係数Γ２の値として、Ｍ個の反射係数値Γ２，１、…、Γ２，Ｍ（Ｍは２以上の整数）が設定可能であるとすれば、合成反射係数Γｓｕｍの値としてＮ×Ｍパターンの反射係数値が設定可能である。 The load control unit 22 individually controls the load impedance states of the first reflector 23 and the second reflector 24, so that the load impedance state of the entire set of the first reflector 23 and the second reflector 24 is as follows. It is possible to generate the same number of states as the number of symbols in the constellation of the multi-level modulation system (16 points in the case of 16-level QAM). In other words, the load control unit 22 generates the same number of combined reflection coefficients Γ sum as the number of symbols of the constellation by individually controlling the load impedance states of the first reflector 23 and the second reflector 24. Is possible. For example, as the value of the first reflection coefficient Γ 1 , N reflection coefficient values Γ 1,1 ,..., Γ 1, N (N is an integer of 2 or more) can be set, and the second reflection coefficient Γ 2 Assuming that M reflection coefficient values Γ 2,1 ,..., Γ 2, M (M is an integer equal to or greater than 2) can be set as values, the value of the combined reflection coefficient Γ sum is an N × M pattern. The reflection coefficient value can be set.
　図４Ａおよび図４Ｂは、１６値ＱＡＭを実現するための第１反射係数Γ１と第２反射係数Γ２の例を示す複素平面図である。図４Ａに示されるように、第１反射係数Γ１は、４個の反射係数値Γ１，１、Γ１，２、Γ１，３、Γ１，４のいずれかの値をとることができ、図４Ｂに示されるように第２反射係数Γ２は、４個の反射係数値Γ２，１、Γ２，２、Γ２，３、Γ２，４のいずれかの値をとることができる。したがって、１６値ＱＡＭのコンステレーションのシンボル数と同数の４×４パターン（＝１６パターン）の合成反射係数Γｓｕｍの値が設定可能である。図５は、各送信シンボルに対応するデータビット値、第１反射係数Γ１および第２反射係数Γ２の間の対応関係の例を示す図である。 4A and 4B are complex plan views showing examples of the first reflection coefficient Γ 1 and the second reflection coefficient Γ 2 for realizing 16-value QAM. As shown in FIG. 4A, the first reflection coefficient Γ 1 may take any one of four reflection coefficient values Γ 1,1 , Γ 1,2 , Γ 1,3 , Γ 1,4. As shown in FIG. 4B, the second reflection coefficient Γ 2 has one of four reflection coefficient values Γ 2,1 , Γ 2,2 , Γ 2,3 , Γ 2,4. Can do. Therefore, it is possible to set the value of the combined reflection coefficient Γ sum of 4 × 4 patterns (= 16 patterns) equal to the number of symbols of the 16-value QAM constellation. Figure 5 is a data bit value corresponding to each transmission symbol is a diagram showing an example of a correspondence between the first reflection coefficient gamma 1 and the second reflection coefficient gamma 2.
　次に、図６および図７を参照しつつ、本実施の形態における第１反射器２３および第２反射器２４の構成について説明する。図６は、第１反射器２３の構成例を示す図であり、図７は、第２反射器２４の構成例を示す図である。 Next, the configuration of the first reflector 23 and the second reflector 24 in the present embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram illustrating a configuration example of the first reflector 23, and FIG. 7 is a diagram illustrating a configuration example of the second reflector 24.
　図６に示されるように第１反射器２３は、電力分配器２１の第１の入出力端に一端が接続された伝送線路３３（第１の伝送線路）と、当該伝送線路３３の他端に接続された電界効果トランジスタ３１とを含む。伝送線路３３は、ＲＦ信号Ｃｗの搬送波周波数を基準として、当該伝送線路３３の両端間に電気長θ（単位：ラジアン）を有する。 As shown in FIG. 6, the first reflector 23 includes a transmission line 33 (first transmission line) having one end connected to the first input / output end of the power distributor 21 and the other end of the transmission line 33. And a field effect transistor 31 connected to the. The transmission line 33 has an electrical length θ (unit: radians) between both ends of the transmission line 33 with reference to the carrier frequency of the RF signal Cw.
　電界効果トランジスタ３１は、制御信号ＧＣ１を入力とする制御端子であるゲート端子３１ｇと、伝送線路３３の他端に接続された被制御端子であるドレイン端子３１ｄと、直流電圧を供給するバイアス電圧源３２に直接接続された被制御端子であるソース端子３１ｓとを有する可変インピーダンス素子である。電界効果トランジスタ３１は、制御信号ＧＣ１の電圧すなわち制御電圧に応じて線形領域で動作するように設計されている。よって、負荷制御部２２は、送信シンボル列の各ビット値に応じた制御電圧をゲート端子３１ｇに供給することによって、電界効果トランジスタ３１のインピーダンス（主に、抵抗値）を多段階で可変に制御することができる。 The field effect transistor 31 includes a gate terminal 31g that is a control terminal that receives the control signal GC1, a drain terminal 31d that is a controlled terminal connected to the other end of the transmission line 33, and a bias voltage source that supplies a DC voltage. This is a variable impedance element having a source terminal 31 s which is a controlled terminal directly connected to 32. The field effect transistor 31 is designed to operate in a linear region in accordance with the voltage of the control signal GC1, that is, the control voltage. Therefore, the load control unit 22 variably controls the impedance (mainly resistance value) of the field effect transistor 31 in multiple stages by supplying a control voltage corresponding to each bit value of the transmission symbol string to the gate terminal 31g. can do.
　図８に示されるような電気長φを有する伝送線路５０について、伝送線路５０の一端５０ｂから伝送線路５０側をみたときの反射係数をΓｂで表し、伝送線路５０の他端５０ａから、伝送線路５０側とは逆側をみたときの反射係数をΓａで表すものとする。このとき、一般に、反射係数Γｂは、反射係数Γａの絶対値｜Γａ｜を用いて次式（７）で表現される。

Figure JPOXMLDOC01-appb-I000006
For the transmission line 50 having the electrical length φ as shown in FIG. 8, the reflection coefficient when the transmission line 50 side is viewed from one end 50 b of the transmission line 50 is represented by Γ b , and transmission is performed from the other end 50 a of the transmission line 50. the line 50 side denote the reflection coefficient when seen opposite side gamma a. At this time, the reflection coefficient Γ b is generally expressed by the following equation (7) using the absolute value | Γ a | of the reflection coefficient Γ a .

Figure JPOXMLDOC01-appb-I000006
　図６を参照すると、第１反射器２３の入出力端部αから伝送線路３３側をみたときの第１反射係数Γ１に対し、ドレイン端子３１ｄの位置での反射面１αから電界効果トランジスタ３１側をみたときの反射係数をΓ１αで表すものとする。このとき、第１反射係数Γ１は、反射係数Γ１αを用いて次式（８）で表現される。

Figure JPOXMLDOC01-appb-I000007
Referring to FIG. 6, with respect to the first reflection coefficient Γ 1 when the transmission line 33 side is viewed from the input / output end α of the first reflector 23, the field effect transistor 31 extends from the reflection surface 1α at the position of the drain terminal 31d. The reflection coefficient when viewed from the side is represented by Γ 1α . At this time, the first reflection coefficient Γ 1 is expressed by the following equation (8) using the reflection coefficient Γ 1α .

Figure JPOXMLDOC01-appb-I000007
　一方、図７に示されるように第２反射器２４は、電力分配器２１の第２の入出力端に一端が接続された伝送線路４３（第２の伝送線路）と、当該伝送線路４３の他端に接続された電界効果トランジスタ４１とを含む。伝送線路４３は、ＲＦ信号Ｃｗの搬送波周波数を基準として、当該伝送線路４３の両端間に電気長θ＋π／４（単位：ラジアン）を有する。 On the other hand, as shown in FIG. 7, the second reflector 24 includes a transmission line 43 (second transmission line) having one end connected to the second input / output end of the power distributor 21, and the transmission line 43. And a field effect transistor 41 connected to the other end. The transmission line 43 has an electrical length θ + π / 4 (unit: radians) between both ends of the transmission line 43 with reference to the carrier frequency of the RF signal Cw.
　電界効果トランジスタ４１は、制御信号ＧＣ２を入力とする制御端子であるゲート端子４１ｇと、伝送線路４３の他端に接続された被制御端子であるドレイン端子４１ｄと、直流電圧を供給するバイアス電圧源４２に直接接続された被制御端子であるソース端子４１ｓとを有する可変インピーダンス素子である。電界効果トランジスタ４１は、制御信号ＧＣ２の電圧すなわち制御電圧に応じて線形領域で動作するように設計されている。よって、負荷制御部２２は、送信シンボル列の各ビット値に応じた制御電圧をゲート端子４１ｇに供給することによって、電界効果トランジスタ４１のインピーダンス（主に、抵抗値）を多段階で可変に制御することができる。 The field effect transistor 41 includes a gate terminal 41g that is a control terminal that receives a control signal GC2, a drain terminal 41d that is a controlled terminal connected to the other end of the transmission line 43, and a bias voltage source that supplies a DC voltage. 42 is a variable impedance element having a source terminal 41 s which is a controlled terminal directly connected to 42. The field effect transistor 41 is designed to operate in a linear region according to the voltage of the control signal GC2, that is, the control voltage. Therefore, the load control unit 22 variably controls the impedance (mainly resistance value) of the field effect transistor 41 in multiple stages by supplying a control voltage corresponding to each bit value of the transmission symbol string to the gate terminal 41g. can do.
　第２反射器２４の入出力端部βから伝送線路４３側をみたときの第２反射係数Γ２に対し、ドレイン端子４１ｄの位置での反射面２βから電界効果トランジスタ４１側をみたときの反射係数をΓ２βで表すものとする。このとき、第２反射係数Γ２は、反射係数Γ２βを用いて次式（９）で表現される。

Figure JPOXMLDOC01-appb-I000008
With respect to the second reflection coefficient gamma 2 as viewed through the transmission line 43 side from the output end of the second reflector 24 beta, reflection when the reflecting surface 2β at the position of the drain terminal 41d viewed field effect transistor 41 side The coefficient is represented by Γ 2β . At this time, the second reflection coefficient Γ 2 is expressed by the following equation (9) using the reflection coefficient Γ 2β .

Figure JPOXMLDOC01-appb-I000008
　本実施の形態では、第１反射器２３の電界効果トランジスタ３１と第２反射器２４の電界効果トランジスタ４１とは同一の特性を有する。このため、電界効果トランジスタ３１，４１のゲート端子３１ｇ，４１ｇに印加される制御電圧が等しい場合、反射係数Γ１α，Γ２βは同一である。たとえば、同一の製造プロセスで製造された、同一ゲート長を有する２個の電界効果トランジスタ３１，４１を使用することで、電界効果トランジスタ３１，４１の特性を同一のものとすることができる。よって、Γ１α＝Γ２βの関係を考慮して、上式（８），（９）から次式（１０）が導出される。

Figure JPOXMLDOC01-appb-I000009
In the present embodiment, the field effect transistor 31 of the first reflector 23 and the field effect transistor 41 of the second reflector 24 have the same characteristics. Therefore, when the control voltages applied to the gate terminals 31g and 41g of the field effect transistors 31 and 41 are equal, the reflection coefficients Γ 1α and Γ 2β are the same. For example, by using two field effect transistors 31 and 41 having the same gate length manufactured by the same manufacturing process, the characteristics of the field effect transistors 31 and 41 can be made the same. Therefore, the following equation (10) is derived from the above equations (8) and (9) in consideration of the relationship of Γ 1α = Γ 2β .

Figure JPOXMLDOC01-appb-I000009
　図９は、１６値ＱＡＭを実現するための反射係数Γ１α，Γ２βの例を示す複素平面図である。図９に示されるように、反射係数Γ１αの値として４個の反射係数値Γ１α，１、…、Γ１α，４が設定可能であり、第２反射係数Γ２βの値として、４個の反射係数値Γ２β，１、…、Γ２β，４が設定可能である。 FIG. 9 is a complex plan view showing an example of reflection coefficients Γ 1α and Γ 2β for realizing 16-value QAM. As shown in FIG. 9, four reflection coefficient value gamma l [alpha] as the value of the reflection coefficient Γ 1α, 1, ..., Γ 1α, 4 are possible settings, as the value of the second reflection coefficient gamma 2.beta, four of the reflection coefficient value Γ 2β, 1, ..., Γ 2β, 4 are possible settings.
　この場合、式（１０）に従い、図４Ａに示した第１反射係数Γ１の値Γ１，１、Γ１，２、Γ１，３、Γ１，４と、図４Ｂに示した第２反射係数Γ２の値Γ２，１、Γ２，２、Γ２，３、Γ２，４との間の関係は、たとえば、次式（１１）～（１４）に示すように設定可能である。

Figure JPOXMLDOC01-appb-I000010
In this case, according to the equation (10), the values Γ 1,1 , Γ 1,2 , Γ 1,3 , Γ 1,4 of the first reflection coefficient Γ 1 shown in FIG. 4A and the second values shown in FIG. The relationship between the values Γ 2,1 , Γ 2,2 , Γ 2,3 , Γ 2,4 of the reflection coefficient Γ 2 can be set as shown in the following equations (11) to (14), for example. is there.

Figure JPOXMLDOC01-appb-I000010
　図１０は、各送信シンボルに対応するデータビット値、第１反射係数Γ１、反射係数Γ１α、第２反射係数Γ２および反射係数Γ２βの間の対応関係の例を示す図である。負荷制御部２２は、図１０の１６パターンを用いて反射係数Γ１α，Γ２βを設定することにより、１６値ＱＡＭに基づく変調を第１反射器２３および第２反射器２４に実行させることができる。 FIG. 10 is a diagram illustrating an example of a correspondence relationship among the data bit value, the first reflection coefficient Γ 1 , the reflection coefficient Γ 1α , the second reflection coefficient Γ 2, and the reflection coefficient Γ 2β corresponding to each transmission symbol. The load control unit 22 sets the reflection coefficients Γ 1α and Γ 2β using the 16 patterns of FIG. 10 to cause the first reflector 23 and the second reflector 24 to perform modulation based on 16-value QAM. it can.
　以上に説明したとおり、実施の形態１では、図６に示したように第１反射器２３は、電力分配器２１の第１の入出力端に一端が接続された伝送線路３３と、この伝送線路３３の他端に接続された電界効果トランジスタ３１とを含み、電界効果トランジスタ３１は、制御信号ＧＣ１を入力とするゲート端子３１ｇと、伝送線路３３の他端に接続されたドレイン端子３１ｄと、バイアス電圧源３２に接続されたソース端子３１ｓとを有する。また、図７に示したように第２反射器２４は、電力分配器２１の第２の入出力端に一端が接続された伝送線路４３と、この伝送線路４３の他端に接続された電界効果トランジスタ４１とを含み、電界効果トランジスタ４１は、制御信号ＧＣ２を入力とするゲート端子４１ｇと、伝送線路４３の他端に接続されたドレイン端子４１ｄと、バイアス電圧源４２に接続されたソース端子４１ｓとを有している。伝送線路３３，４３の電気長は互いに異なるように設定されている。負荷制御部２２は、変調器２６で生成された送信シンボル列に基づき、第１反射器２３および第２反射器２４の可変インピーダンスＺ１，Ｚ２をそれぞれ多段階で定める制御信号ＧＣ１，ＧＣ２を生成することができる。したがって、多値変調方式のコンステレーションのシンボル数が多くても、小回路規模の無線通信装置２０を提供することができる。 As described above, in the first embodiment, as shown in FIG. 6, the first reflector 23 includes the transmission line 33 having one end connected to the first input / output end of the power distributor 21 and the transmission line 33. A field effect transistor 31 connected to the other end of the line 33. The field effect transistor 31 includes a gate terminal 31g that receives the control signal GC1; a drain terminal 31d connected to the other end of the transmission line 33; A source terminal 31 s connected to the bias voltage source 32. As shown in FIG. 7, the second reflector 24 includes a transmission line 43 having one end connected to the second input / output end of the power distributor 21 and an electric field connected to the other end of the transmission line 43. The field effect transistor 41 includes a gate terminal 41 g that receives the control signal GC 2, a drain terminal 41 d connected to the other end of the transmission line 43, and a source terminal connected to the bias voltage source 42. 41s. The electrical lengths of the transmission lines 33 and 43 are set to be different from each other. Based on the transmission symbol sequence generated by the modulator 26, the load control unit 22 generates control signals GC1 and GC2 that respectively determine the variable impedances Z 1 and Z 2 of the first reflector 23 and the second reflector 24 in multiple stages. Can be generated. Therefore, even when the number of symbols of the constellation of the multi-level modulation method is large, it is possible to provide the wireless communication device 20 having a small circuit scale.
　上述のとおり、非特許文献１に開示されている従来のＲＦＩＤタグでは、多値変調方式のコンステレーションのシンボル数と同数の反射器と、これら反射器を切り替えるＲＦスイッチ回路とが必要となることから、多値変調方式のコンステレーションのシンボル数が多くなると、回路構成が大規模化する。これに対し、本実施の形態の無線通信装置２０では、コンステレーションのシンボル数増大に伴う回路規模の増大を抑制することができるので、従来のＲＦＩＤタグと比べると、低コストで小型のＲＦＩＤタグを製造することが可能である。 As described above, the conventional RFID tag disclosed in Non-Patent Document 1 requires the same number of reflectors as the number of symbols in the constellation of the multi-level modulation method, and an RF switch circuit for switching these reflectors. Therefore, as the number of symbols in the constellation of the multi-level modulation system increases, the circuit configuration becomes larger. On the other hand, in the wireless communication device 20 according to the present embodiment, an increase in circuit scale associated with an increase in the number of constellation symbols can be suppressed. Can be manufactured.
　また、第１反射器２３の伝送線路３３は、可変インピーダンス素子として動作する電界効果トランジスタ３１のドレイン端子３１ｄと第１反射器２３の入出力端部αとの間に設けられており（図６）、第２反射器２４の伝送線路４３は、可変インピーダンス素子として動作する電界効果トランジスタ４１のドレイン端子４１ｄと第２反射器２４の入出力端部βとの間に設けられている（図７）。伝送線路３３，４３の電気長は互いに異なる。このため、負荷制御部２２は、２本の制御信号ＧＣ１，ＧＣ２を用いるだけで、第１反射器２３および第２反射器２４の組全体の負荷インピーダンス状態を多段階で可変に制御することができる。第１反射器２３および第２反射器２４の負荷インピーダンス状態を制御するために、さらなるスイッチ回路を設ける必要がなく、また、制御信号ＧＣ１，ＧＣ２を伝達する制御信号線以外の、さらなる制御信号線を配線する必要がない。よって、シンプルで小規模な回路構成を実現することができる。 The transmission line 33 of the first reflector 23 is provided between the drain terminal 31d of the field effect transistor 31 operating as a variable impedance element and the input / output end α of the first reflector 23 (FIG. 6). The transmission line 43 of the second reflector 24 is provided between the drain terminal 41d of the field effect transistor 41 operating as a variable impedance element and the input / output end β of the second reflector 24 (FIG. 7). ). The electrical lengths of the transmission lines 33 and 43 are different from each other. For this reason, the load control unit 22 can variably control the load impedance state of the entire set of the first reflector 23 and the second reflector 24 in multiple steps only by using the two control signals GC1 and GC2. it can. In order to control the load impedance state of the first reflector 23 and the second reflector 24, it is not necessary to provide a further switch circuit, and further control signal lines other than the control signal lines for transmitting the control signals GC1 and GC2 are provided. There is no need to wire. Therefore, a simple and small-scale circuit configuration can be realized.
実施の形態２．
　次に、本発明に係る実施の形態２である無線通信システムについて説明する。図１１は、実施の形態２における無線通信装置２０Ａの構成例を示すブロック図である。図１１に示される無線通信装置２０Ａは、データ送信装置として動作し、アンテナ素子Ａ２、電力分配器２１、負荷制御部２２Ａ、第１反射器２３Ａ、第２反射器２４Ａ、送信データ記憶部２５および変調器２６を備えている。無線通信装置２０Ａの構成は、負荷制御部２２Ａ、第１反射器２３Ａおよび第２反射器２４Ａを除き、図１に示した無線通信装置２０の構成と同じである。 Embodiment 2. FIG.
Next, a radio communication system according to the second embodiment of the present invention will be described. FIG. 11 is a block diagram illustrating a configuration example of the wireless communication device 20A according to the second embodiment. A wireless communication device 20A shown in FIG. 11 operates as a data transmission device, and includes an antenna element A2, a power distributor 21, a load control unit 22A, a first reflector 23A, a second reflector 24A, a transmission data storage unit 25, and A modulator 26 is provided. The configuration of the wireless communication device 20A is the same as the configuration of the wireless communication device 20 illustrated in FIG. 1 except for the load control unit 22A, the first reflector 23A, and the second reflector 24A.
　本実施の形態の第１反射器２３Ａは、制御信号ＢＣ１（第１の制御信号）に応じて定まる可変インピーダンスＺ１（第１の可変インピーダンス）を有する負荷回路であり、制御信号ＢＣ１を伝達する単一の制御信号線を介して負荷制御部２２Ａと接続されている。実施の形態１の第１反射器２３と同様に、第１反射器２３Ａは、可変インピーダンスＺ１に応じて定まる第１反射係数Γ１で受信ＲＦ信号Ｃｗ１を反射させ、かつ多段階で変調させることによって反射信号Ｍｗ１（第１の反射信号）を生成する。 The first reflector 23A of the present embodiment is a load circuit having a variable impedance Z 1 (first variable impedance) determined according to a control signal BC1 (first control signal), and transmits the control signal BC1. It is connected to the load control unit 22A through a single control signal line. Like the first reflector 23 of the first embodiment, the first reflector 23A may reflects the received RF signal Cw1 in the first reflection coefficient gamma 1 determined in accordance with the variable impedance Z 1, and is modulated in multiple steps Thus, the reflection signal Mw1 (first reflection signal) is generated.
　図１２は、第１反射器２３Ａの構成例を示す図である。図１２に示されるように第１反射器２３Ａは、電力分配器２１の第１の入出力端に一端が接続された伝送線路３３（第１の伝送線路）と、当該伝送線路３３の他端に接続されたバイポーラトランジスタ６１とを含む。バイポーラトランジスタ６１は、制御信号ＢＣ１を入力とする制御端子であるベース端子６１ｂと、伝送線路３３の他端に接続された被制御端子であるエミッタ端子６１ｅと、バイアス電圧源３２Ａに直接接続された被制御端子であるコレクタ端子６１ｃとを有する可変インピーダンス素子である。負荷制御部２２Ａは、変調器２６で生成された送信シンボル列の各ビット値に応じた制御信号ＢＣ１をベース端子６１ｂに供給することによって、バイポーラトランジスタ６１のインピーダンス（主に、抵抗値）を多段階で可変に制御することができる。 FIG. 12 is a diagram illustrating a configuration example of the first reflector 23A. As shown in FIG. 12, the first reflector 23 </ b> A includes a transmission line 33 (first transmission line) having one end connected to the first input / output end of the power distributor 21 and the other end of the transmission line 33. And a bipolar transistor 61 connected to. The bipolar transistor 61 is directly connected to a base terminal 61b that is a control terminal that receives the control signal BC1, an emitter terminal 61e that is a controlled terminal connected to the other end of the transmission line 33, and a bias voltage source 32A. This is a variable impedance element having a collector terminal 61c which is a controlled terminal. The load control unit 22A increases the impedance (mainly resistance value) of the bipolar transistor 61 by supplying a control signal BC1 corresponding to each bit value of the transmission symbol sequence generated by the modulator 26 to the base terminal 61b. It can be variably controlled in stages.
　一方、第２反射器２４Ａは、制御信号ＢＣ２（第２の制御信号）に応じて定まる可変インピーダンスＺ２（第２の可変インピーダンス）を有する負荷回路であり、制御信号ＢＣ２を伝達する単一の制御信号線を介して負荷制御部２２Ａと接続されている。実施の形態１の第２反射器２４と同様に、第２反射器２４Ａは、可変インピーダンスＺ２に応じて定まる第２反射係数Γ２で受信ＲＦ信号Ｃｗ２を反射させ、かつ多段階で変調させることによって反射信号Ｍｗ２（第２の反射信号）を生成する。 On the other hand, the second reflector 24A is a load circuit having a variable impedance Z 2 (second variable impedance) determined according to the control signal BC2 (second control signal), and is a single circuit that transmits the control signal BC2. The load control unit 22A is connected via a control signal line. Similar to the second reflector 24 of the first embodiment, the second reflector 24A reflects the received RF signal Cw2 with a second reflection coefficient Γ 2 determined according to the variable impedance Z 2 and modulates it in multiple steps. Thus, the reflection signal Mw2 (second reflection signal) is generated.
　図１３は、第２反射器２４Ａの構成例を示す図である。図１３に示されるように第２反射器２４Ａは、電力分配器２１の第２の入出力端に一端が接続された伝送線路４３（第２の伝送線路）と、当該伝送線路４３の他端に接続されたバイポーラトランジスタ７１とを含む。バイポーラトランジスタ７１は、制御信号ＢＣ２を入力とする制御端子であるベース端子７１ｂと、伝送線路４３の他端に接続された被制御端子であるエミッタ端子７１ｅと、バイアス電圧源４２Ａに直接接続された被制御端子であるコレクタ端子７１ｃとを有する可変インピーダンス素子である。負荷制御部２２Ａは、変調器２６で生成された送信シンボル列の各ビット値に応じた制御信号ＢＣ２をベース端子７１ｂに供給することによって、バイポーラトランジスタ７１のインピーダンス（主に、抵抗値）を多段階で可変に制御することができる。 FIG. 13 is a diagram illustrating a configuration example of the second reflector 24A. As shown in FIG. 13, the second reflector 24 </ b> A includes a transmission line 43 (second transmission line) having one end connected to the second input / output end of the power distributor 21 and the other end of the transmission line 43. And a bipolar transistor 71 connected to the. The bipolar transistor 71 is directly connected to a base terminal 71b that is a control terminal that receives the control signal BC2, an emitter terminal 71e that is a controlled terminal connected to the other end of the transmission line 43, and a bias voltage source 42A. This is a variable impedance element having a collector terminal 71c which is a controlled terminal. The load control unit 22A increases the impedance (mainly, the resistance value) of the bipolar transistor 71 by supplying a control signal BC2 corresponding to each bit value of the transmission symbol sequence generated by the modulator 26 to the base terminal 71b. It can be variably controlled in stages.
　電力分配器２１は、第１反射器２３Ａおよび第２反射器２４Ａからそれぞれ入力された反射信号Ｍｗ１，Ｍｗ２を電力合成して変調波信号Ｍｗを生成する。変調波信号Ｍｗは、アンテナ素子Ａ２から無線通信装置１０に向けて送信される。 The power distributor 21 combines the reflected signals Mw1 and Mw2 input from the first reflector 23A and the second reflector 24A, respectively, to generate a modulated wave signal Mw. The modulated wave signal Mw is transmitted from the antenna element A2 toward the wireless communication device 10.
　本実施の形態では、第１反射器２３Ａのバイポーラトランジスタ６１と第２反射器２４Ａのバイポーラトランジスタ７１とは同一の特性を有する。このため、エミッタ端子６１ｅの位置での反射面１αからみたときの反射係数Γ１αと、エミッタ端子７１ｅの位置での反射面２βからみたときの反射係数Γ２βとは、同一である。実施の形態１の場合と同様に、負荷制御部２２Ａは、反射係数Γ１α，Γ２βを設定することにより、１６値ＱＡＭなどの多値変調方式に基づく変調を第１反射器２３Ａおよび第２反射器２４Ａに実行させることができる。 In the present embodiment, the bipolar transistor 61 of the first reflector 23A and the bipolar transistor 71 of the second reflector 24A have the same characteristics. Therefore, the reflection coefficient Γ 1α when viewed from the reflection surface 1α at the position of the emitter terminal 61e is the same as the reflection coefficient Γ 2β when viewed from the reflection surface 2β at the position of the emitter terminal 71e. As in the case of the first embodiment, the load control unit 22A sets the reflection coefficients Γ 1α and Γ 2β to perform modulation based on a multi-level modulation scheme such as 16-value QAM and the second reflector 23A and the second reflector 23A. It can be performed by the reflector 24A.
　以上に説明したとおり、実施の形態２では、図１２に示したように第１反射器２３Ａは、電力分配器２１の第１の入出力端に一端が接続された伝送線路３３と、この伝送線路３３の他端に接続されたバイポーラトランジスタ６１とを含み、バイポーラトランジスタ６１は、制御信号ＢＣ１を入力とするベース端子６１ｂと、伝送線路３３の他端に接続されたエミッタ端子６１ｅと、バイアス電圧源３２Ａに接続されたコレクタ端子６１ｃとを有する。また、図１３に示したように第２反射器２４Ａは、電力分配器２１の第２の入出力端に一端が接続された伝送線路４３と、この伝送線路４３の他端に接続されたバイポーラトランジスタ７１とを含み、バイポーラトランジスタ７１は、制御信号ＢＣ２を入力とするベース端子７１ｂと、伝送線路４３の他端に接続されたエミッタ端子７１ｅと、バイアス電圧源４２Ａに接続されたコレクタ端子７１ｃとを有している。負荷制御部２２Ａは、変調器２６で生成された送信シンボル列に基づき、第１反射器２３Ａおよび第２反射器２４Ａの可変インピーダンスＺ１，Ｚ２をそれぞれ多段階で定める制御信号ＢＣ１，ＢＣ２を生成することができる。したがって、多値変調方式のコンステレーションのシンボル数が多くても、小回路規模の無線通信装置２０Ａを提供することができる。また、コンステレーションのシンボル数増大に伴う回路規模の増大を抑制することができるので、従来のＲＦＩＤタグと比べると、低コストで小型のＲＦＩＤタグを製造することが可能である。 As described above, in the second embodiment, as shown in FIG. 12, the first reflector 23A includes the transmission line 33 having one end connected to the first input / output end of the power distributor 21, and the transmission line 33. A bipolar transistor 61 connected to the other end of the line 33. The bipolar transistor 61 includes a base terminal 61b that receives the control signal BC1, an emitter terminal 61e connected to the other end of the transmission line 33, and a bias voltage. And a collector terminal 61c connected to the source 32A. As shown in FIG. 13, the second reflector 24 </ b> A includes a transmission line 43 having one end connected to the second input / output end of the power distributor 21 and a bipolar connected to the other end of the transmission line 43. The bipolar transistor 71 includes a base terminal 71b that receives the control signal BC2, an emitter terminal 71e connected to the other end of the transmission line 43, and a collector terminal 71c connected to the bias voltage source 42A. have. Based on the transmission symbol sequence generated by the modulator 26, the load control unit 22A generates control signals BC1 and BC2 that determine the variable impedances Z 1 and Z 2 of the first reflector 23A and the second reflector 24A in multiple stages, respectively. Can be generated. Therefore, even when the number of symbols of the constellation of the multilevel modulation system is large, it is possible to provide the radio communication device 20A having a small circuit scale. In addition, since an increase in circuit scale accompanying an increase in the number of constellation symbols can be suppressed, a small RFID tag can be manufactured at a lower cost than a conventional RFID tag.
　また、第１反射器２３Ａの伝送線路３３は、可変インピーダンス素子として動作するバイポーラトランジスタ６１のエミッタ端子６１ｅと第１反射器２３Ａの入出力端部αとの間に設けられており（図１２）、第２反射器２４Ａの伝送線路４３は、可変インピーダンス素子として動作するバイポーラトランジスタ７１のエミッタ端子７１ｅと第２反射器２４の入出力端部βとの間に設けられている（図１３）。伝送線路３３，４３の電気長は互いに異なる。このため、負荷制御部２２Ａは、２本の制御信号ＢＣ１，ＢＣ２を用いるだけで、第１反射器２３Ａおよび第２反射器２４Ａの組全体の負荷インピーダンス状態を多段階で可変に制御することができる。第１反射器２３Ａおよび第２反射器２４Ａの負荷インピーダンス状態を制御するために、さらなるスイッチ回路を設ける必要がなく、また、制御信号ＢＣ１，ＢＣ２を伝達する制御信号線以外の、さらなる制御信号線を配線する必要がない。よって、シンプルで小規模な回路構成を実現することができる。 The transmission line 33 of the first reflector 23A is provided between the emitter terminal 61e of the bipolar transistor 61 operating as a variable impedance element and the input / output end α of the first reflector 23A (FIG. 12). The transmission line 43 of the second reflector 24A is provided between the emitter terminal 71e of the bipolar transistor 71 operating as a variable impedance element and the input / output end β of the second reflector 24 (FIG. 13). The electrical lengths of the transmission lines 33 and 43 are different from each other. For this reason, the load control unit 22A can variably control the load impedance state of the entire set of the first reflector 23A and the second reflector 24A in multiple stages only by using the two control signals BC1 and BC2. it can. In order to control the load impedance states of the first reflector 23A and the second reflector 24A, it is not necessary to provide a further switch circuit, and further control signal lines other than the control signal lines for transmitting the control signals BC1 and BC2 There is no need to wire. Therefore, a simple and small-scale circuit configuration can be realized.
　以上、図面を参照して本発明に係る種々の実施の形態について述べたが、これら実施の形態は本発明の例示であり、これら実施の形態以外の様々な形態を採用することもできる。たとえば、実施の形態１，２における第１反射係数Γ１の位相と第２反射係数Γ２の位相とは直交関係を有することが好ましいが、これに限定されるものではない。第１反射係数Γ１の位相と第２反射係数Γ２の位相とが相違していればよい。 Although various embodiments according to the present invention have been described above with reference to the drawings, these embodiments are examples of the present invention, and various forms other than these embodiments can be adopted. For example, it is preferable that the phase of the first reflection coefficient Γ 1 and the phase of the second reflection coefficient Γ 2 in Embodiments 1 and 2 have an orthogonal relationship, but the present invention is not limited to this. It is only necessary that the phase of the first reflection coefficient Γ 1 is different from the phase of the second reflection coefficient Γ 2 .
　また、実施の形態１，２で採用される多値変調方式は、１６値ＱＡＭに限定されるものではない。１６値ＱＡＭに代えて、たとえば、ＱＰＳＫ（Ｑｕａｄｒａｔｕｒｅ　Ｐｈａｓｅ　Ｓｈｉｆｔ　Ｋｅｙｉｎｇ）、π／４シフトＱＰＳＫ、６４値ＱＡＭまたは２５６値ＱＡＭが採用されてもよい。 Further, the multi-level modulation method adopted in the first and second embodiments is not limited to 16-value QAM. Instead of 16-value QAM, for example, QPSK (Quadrature Phase Shift Keying), π / 4 shift QPSK, 64-value QAM, or 256-value QAM may be employed.
　本発明の範囲内において、上記実施の形態１，２の自由な組み合わせ、各実施の形態の任意の構成要素の変形、または各実施の形態の任意の構成要素の省略が可能である。 Within the scope of the present invention, the above-described first and second embodiments can be freely combined, any constituent element of each embodiment can be modified, or any constituent element of each embodiment can be omitted.
　本発明に係る無線通信装置および無線通信システムは、バックスキャッタ変調方式で動作し、多値変調方式のコンステレーションのシンボル数が多くても、シンプルで小規模な回路構成を実現することができるので、ＲＦＩＤタグなどの、低消費電力で動作する小型かつ軽量なデータ送信装置に適している。 The wireless communication apparatus and the wireless communication system according to the present invention operate in the backscatter modulation scheme, and can realize a simple and small circuit configuration even if the number of constellations in the multilevel modulation scheme is large. It is suitable for a small and lightweight data transmission device that operates with low power consumption, such as an RFID tag.
　Ａ１，Ａ２　アンテナ素子、１　無線通信システム、１０　無線通信装置、１１　通信制御部、１２　ＰＬＬ回路、１３　送信回路、１４　方向性結合器、１５　受信回路、１６　復調器、２０，２０Ａ　無線通信装置、２１　電力分配器、２２，２２Ａ　負荷制御部、２３，２３Ａ　第１反射器、２４，２４Ａ　第２反射器、２５　送信データ記憶部、２６　変調器、３１，４１　電界効果トランジスタ、３２，３２Ａ，４２，４２Ａ　バイアス電圧源、３３，４３，５０　伝送線路、６１，７１　バイポーラトランジスタ。 A1, A2 antenna element, 1 wireless communication system, 10 wireless communication device, 11 communication control unit, 12 PLL circuit, 13 transmission circuit, 14 directional coupler, 15 reception circuit, 16 demodulator, 20, 20A wireless communication device, 21, power divider, 22, 22A, load controller, 23, 23A, first reflector, 24, 24A, second reflector, 25, transmission data storage, 26 modulator, 31, 41, field effect transistor, 32, 32A, 42 , 42A bias voltage source, 33, 43, 50 transmission line, 61, 71 bipolar transistor.

Claims (9)

  1. 　アンテナ素子で受信された高周波信号を電力分配して第１の受信信号および第２の受信信号を自己の第１の入出力端および第２の入出力端からそれぞれ出力し、前記第１の受信信号に対する第１の反射信号と前記第２の受信信号に対する第２の反射信号とを電力合成して前記アンテナ素子から送信されるべき変調波信号を生成する電力分配器と、
    　第１の可変インピーダンスを有し、前記第１の可変インピーダンスに応じて定まる第１反射係数で前記第１の受信信号を反射かつ変調させることによって前記第１の反射信号を生成する第１反射器と、
    　第２の可変インピーダンスを有し、前記第２の可変インピーダンスに応じて定まる第２反射係数で前記第２の受信信号を反射かつ変調させることによって前記第２の反射信号を生成する第２反射器と、
    　所定の多値変調方式に従って生成された送信シンボル列に基づき、前記第１の可変インピーダンスを定める第１の制御信号と前記第２の可変インピーダンスを定める第２の制御信号とを生成する負荷制御部と
    を備え、
    　前記第１反射器は、
    　前記第１の入出力端に一端が接続された第１の伝送線路と、
    　前記第１の伝送線路の他端およびバイアス電圧源にそれぞれ接続された一対の被制御端子を有するとともに前記第１の制御信号を入力とする制御端子を有する第１のトランジスタとを含み、
    　前記第２反射器は、
    　前記第２の入出力端に一端が接続され、前記第１の伝送線路の電気長とは異なる電気長を有する第２の伝送線路と、
    　前記第２の伝送線路の他端および他のバイアス電圧源にそれぞれ接続された一対の被制御端子を有するとともに前記第２の制御信号を入力とする制御端子を有する第２のトランジスタとを含む、
    ことを特徴とする無線通信装置。     The first reception signal and the second reception signal are respectively output from the first input / output terminal and the second input / output terminal of the first high-frequency signal received by the antenna element, and the first reception signal is output. A power divider that generates a modulated wave signal to be transmitted from the antenna element by combining the power of the first reflected signal with respect to the signal and the second reflected signal with respect to the second received signal;
    A first reflector having a first variable impedance and generating the first reflected signal by reflecting and modulating the first received signal with a first reflection coefficient determined according to the first variable impedance When,
    A second reflector having a second variable impedance and generating the second reflected signal by reflecting and modulating the second received signal with a second reflection coefficient determined according to the second variable impedance. When,
    A load control unit that generates a first control signal that defines the first variable impedance and a second control signal that defines the second variable impedance based on a transmission symbol sequence generated according to a predetermined multilevel modulation scheme And
    The first reflector includes:
    A first transmission line having one end connected to the first input / output end;
    A first transistor having a pair of controlled terminals respectively connected to the other end of the first transmission line and a bias voltage source and having a control terminal for receiving the first control signal;
    The second reflector is
    A second transmission line having one end connected to the second input / output end and having an electrical length different from the electrical length of the first transmission line;
    A second transistor having a pair of controlled terminals respectively connected to the other end of the second transmission line and another bias voltage source and having a control terminal for inputting the second control signal;
    A wireless communication apparatus.
  2. 　請求項１記載の無線通信装置であって、前記負荷制御部は、前記第１のトランジスタのインピーダンスを多段階で可変に制御し、かつ前記第２のトランジスタのインピーダンスを多段階で可変に制御することを特徴とする無線通信装置。 2. The wireless communication apparatus according to claim 1, wherein the load control unit variably controls the impedance of the first transistor in multiple stages and variably controls the impedance of the second transistor in multiple stages. A wireless communication apparatus.
  3. 　請求項１または請求項２記載の無線通信装置であって、前記第１の伝送線路の電気長と前記第２の伝送線路の電気長とは、前記高周波信号の搬送波周波数を基準としてπ／４だけ互いにずれていることを特徴とする無線通信装置。 3. The wireless communication device according to claim 1, wherein an electrical length of the first transmission line and an electrical length of the second transmission line are π / 4 based on a carrier frequency of the high-frequency signal. A wireless communication device characterized in that they are offset from each other only.
  4. 　請求項３記載の無線通信装置であって、前記第１反射係数と前記第２反射係数とが直交関係を有することを特徴とする無線通信装置。 4. The wireless communication apparatus according to claim 3, wherein the first reflection coefficient and the second reflection coefficient have an orthogonal relationship.
  5. 　請求項１または請求項２記載の無線通信装置であって、
    　前記負荷制御部から前記第１のトランジスタの当該制御端子へ前記第１の制御信号を伝達する単一の制御信号線と、
    　前記負荷制御部から前記第２のトランジスタの当該制御端子へ前記第２の制御信号を伝達する単一の制御信号線と
    をさらに備えることを特徴とする無線通信装置。     The wireless communication device according to claim 1 or 2,
    A single control signal line for transmitting the first control signal from the load controller to the control terminal of the first transistor;
    A wireless communication device further comprising: a single control signal line for transmitting the second control signal from the load control unit to the control terminal of the second transistor.
  6. 　請求項１または請求項２記載の無線通信装置であって、前記第１のトランジスタおよび前記第２のトランジスタは、前記制御端子としてゲート端子を有し、前記被制御端子としてソース端子およびドレイン端子を有する電界効果トランジスタであることを特徴とする無線通信装置。 3. The wireless communication apparatus according to claim 1, wherein the first transistor and the second transistor have a gate terminal as the control terminal, and have a source terminal and a drain terminal as the controlled terminal. A wireless communication device comprising a field effect transistor.
  7. 　請求項１または請求項２記載の無線通信装置であって、前記第１のトランジスタおよび前記第２のトランジスタは、前記制御端子としてベース端子を有し、前記被制御端子としてコレクタ端子およびエミッタ端子を有するバイポーラトランジスタであることを特徴とする無線通信装置。 3. The wireless communication apparatus according to claim 1, wherein the first transistor and the second transistor have a base terminal as the control terminal, and a collector terminal and an emitter terminal as the controlled terminal. A wireless communication device comprising a bipolar transistor.
  8. 　請求項１または請求項２記載の無線通信装置であって、前記所定の多値変調方式のコンスタレーションに従い、データビット列に一次変調を施して前記送信シンボル列を生成する変調器をさらに備えることを特徴とする無線通信装置。 3. The radio communication apparatus according to claim 1, further comprising a modulator that performs primary modulation on a data bit string to generate the transmission symbol string in accordance with a constellation of the predetermined multilevel modulation scheme. A wireless communication device.
  9. 　請求項１から請求項８のうちのいずれか１項記載の無線通信装置と、
    　前記高周波信号を前記無線通信装置に向けて送信するデータ受信装置と
    を備え、
    　前記無線通信装置は、前記高周波信号に応答して前記変調波信号を送信し、
    　前記データ受信装置は、前記無線通信装置から前記変調波信号を受信する、
    ことを特徴とする無線通信システム。     A wireless communication device according to any one of claims 1 to 8,
    A data receiving device that transmits the high-frequency signal toward the wireless communication device;
    The wireless communication device transmits the modulated wave signal in response to the high-frequency signal,
    The data receiving device receives the modulated wave signal from the wireless communication device;
    A wireless communication system.
PCT/JP2018/019362 2018-05-18 2018-05-18 Wireless communication device and wireless communication system WO2019220637A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008104025A (en) * 2006-10-19 2008-05-01 Sony Corp Radio communication apparatus
JP2009232372A (en) * 2008-03-25 2009-10-08 Sony Corp Communication system and communication apparatus
JP2015525033A (en) * 2012-07-11 2015-08-27 タグ−コム インコーポレイテッド Transmission device for wireless devices

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008104025A (en) * 2006-10-19 2008-05-01 Sony Corp Radio communication apparatus
JP2009232372A (en) * 2008-03-25 2009-10-08 Sony Corp Communication system and communication apparatus
JP2015525033A (en) * 2012-07-11 2015-08-27 タグ−コム インコーポレイテッド Transmission device for wireless devices

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