Transmission circuits and composite transmission circuits

Abstract

This transmission circuit comprises: a plurality of impedance circuits each having a different impedance; a plurality of switch elements, one of which is connected to each of the plurality of impedance circuits; a compensation circuit connected to each of the plurality of switch elements and selectively adding a capacitance value and a resistance value to the transmission circuit; and a control circuit configured to control opening and closing of the plurality of switch elements. The control circuit is configured to selectively change the opening and closing of the plurality of switch elements so as to control the reflection coefficient of the output terminal on the antenna side to rotate in the complex plane.

Description

[Technical field]

[0001] The present disclosure relates to a transmission circuit and a composite transmission circuit. [Background technology]

[0002] A backscattering method is known as a data communication method for wireless communication devices. For example, Patent Document 1 discloses a technique for realizing a single sideband by suppressing either an upper sideband (USB) signal or a lower sideband (LSB) signal using a splitter / combiner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-323223 A Summary of the Invention

[0004] A transmission circuit according to one embodiment of the present disclosure is a transmission circuit configured to be connected to an antenna, the transmission circuit including a plurality of impedance circuits each having a different impedance, a plurality of switch elements, one of which is connected to each of the plurality of impedance circuits, a compensation circuit connected to each of the plurality of switch elements and selectively adding a capacitance value and a resistance value to the transmission circuit, and a control circuit configured to control the opening and closing of the plurality of switch elements, the control circuit being configured to selectively change the opening and closing of the plurality of switch elements to control the reflection coefficient of the output terminal on the antenna side to rotate in a complex plane.

[0005] A composite transmission circuit according to one embodiment of the present disclosure is a composite transmission circuit configured to be connected to an antenna, the composite transmission circuit including at least a first transmission circuit having a first characteristic related to a capacitance value and a resistance value, a second transmission circuit having a second characteristic related to the capacitance value and the resistance value that is different from the first characteristic, and a third transmission circuit having a third characteristic related to the capacitance value and the resistance value that is different from the first characteristic and the second characteristic. The composite transmission circuit includes a switch control circuit configured to selectively connect the first transmission circuit, the second transmission circuit, and the third transmission circuit to the antenna, each of the first transmission circuit, the second transmission circuit, and the third transmission circuit including a plurality of impedance circuits each having a different impedance, a plurality of switch elements, one of which is connected to each of the plurality of impedance circuits, and a control circuit configured to control the opening and closing of the plurality of switch elements. The control circuit is configured to selectively change the opening and closing of the plurality of switch elements to control the reflection coefficient of the output terminal on the antenna side to rotate in a complex plane. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a wireless communication device according to the first embodiment. [Diagram 2] FIG. 2 is a diagram for explaining a method for controlling the rotation of impedance on a complex plane according to the first embodiment. [Figure 3A] FIG. 3A is a diagram for explaining a change in a backscatter signal. [Figure 3B] FIG. 3B is a diagram for explaining a change in the backscatter signal. [Figure 3C] FIG. 3C is a diagram for explaining a change in the backscatter signal. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of a transmission circuit according to the first embodiment. [Diagram 5] FIG. 5 is a diagram for explaining a method of rotating and controlling the reflection coefficient on a complex plane according to the first embodiment. [Figure 6]FIG. 6 is a block diagram showing an example of the configuration of a wireless communication device according to the second embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the configuration of a transmission circuit according to the second embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of the compensation circuit according to the second embodiment. [Figure 9] FIG. 9 is a block diagram showing an example of the configuration of a wireless communication device according to the third embodiment. [Figure 10] FIG. 10 is a diagram for explaining an example of the configuration of the composite transmission circuit according to the third embodiment. [Figure 11] FIG. 11 is a diagram for explaining a method of rotating and controlling the reflection coefficient on a complex plane according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes a configuration in which each embodiment is combined. In the following embodiments, the same parts are denoted by the same reference numerals, and duplicated descriptions are omitted.

[0008] [First embodiment] The configuration of the wireless communication device according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the wireless communication device according to the embodiment.

[0009] 1, the wireless communication device 1 includes an antenna 10, a BPF (Band Pass Filter) 11, an RFBS (Radio Frequency Back Scatter) device 20, a control device 30, and a sensor 40. The wireless communication device 1 is a communication device configured to perform wireless communication using a backscatter method such as RFID.

[0010] The antenna 10 is configured to receive a signal transmitted to the wireless communication device 1. The antenna 10 is configured to transmit radio waves toward the outside of the wireless communication device 1. The BPF 11 is a filter configured to pass a signal in a desired frequency band.

[0011] The RFBS device 20 includes a high frequency switch 21, an amplifier 22, a demodulator 23, an oscillator 24, an LPF (Low Pass Filter) 25, an LPF 26, a control circuit 27, and a transmission circuit 28. The RFBS device 20 is a wireless communication device that supports backscattering data communication. In backscattering data communication, communication is performed by utilizing the reflection of transmitted radio waves.

[0012] The high frequency switch 21 is configured to switch the connection between the antenna 10 and a transmission circuit system or a reception circuit system. The high frequency switch 21 is configured to be able to connect the transmission circuit system to the antenna 10. The wireless communication device 1 is configured to transmit when the antenna 10 is connected to the transmission circuit system. The high frequency switch 21 is configured to be able to connect the reception circuit system to the antenna 10. The transmission circuit system includes an oscillator 24, an LPF 25, an LPF 26, a control circuit 27, and a transmission circuit 28. The reception circuit system includes an amplifier 22 and a demodulator 23.

[0013] The amplifier 22 is configured to amplify and output a signal received from the antenna 10. The amplifier 22 is configured to output the amplified signal to the demodulation unit 23. The demodulation unit 23 is configured to perform demodulation processing on the input signal. The demodulation unit 23 is configured to demodulate the signal received from the amplifier 22. For example, the demodulation unit 23 is configured to perform demodulation processing on the signal received from the amplifier 22 (a modulated signal such as ASK (Amplitude Shift Keying)).

[0014] The control device 30 is realized, for example, by a processor or the like executing a program stored therein using a RAM (Random Access Memory) or the like as a working area. The control device 30 may be a controller. The control device 30 may be realized, for example, by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 30 may be realized by a combination of software and hardware.

[0015] The control device 30 is configured to output serial data S1 to the control circuit 27 via the LPF 25. The serial data S1 is based on output data from the sensor 40. The control device 30 outputs serial data S2 to the control circuit 27 via the LPF 26. The serial data S2 is based on output data from the sensor 40. The serial data S1 has a phase difference of approximately 90° with respect to the serial data S2.

[0016] The control device 30 is configured to output a control signal S3 to the control circuit 27. The control signal S3 can be used to suppress either the USB signal or the LSB signal relative to the carrier signal. The control device 30 is configured to output a control signal S4 to the oscillator 24. The control signal S4 can be used to control a channel used for communication.

[0017] The sensor 40 is configured to detect various physical quantities. There is no particular limit to the physical quantities detected by the sensor 40. The sensor 40 may include, for example, one or both of a temperature sensor configured to detect the temperature around the wireless communication device 1 and an acceleration sensor configured to detect acceleration occurring in the wireless communication device 1. The sensor 40 may include other sensors.

[0018] The oscillator 24 is configured to generate an oscillation signal of a predetermined frequency. The oscillator 24 is configured to generate an oscillation signal S5 in accordance with a control signal S4. The oscillator 24 is configured to generate an oscillation signal S6 that is 90° out of phase with the oscillation signal S5.

[0019] The control circuit 27 is configured to control the transmission circuit 28. The control circuit 27 is configured to control the transmission circuit 28 so as to adjust the impedance value of the transmission circuit 28 based on the serial data S1, the serial data S2, and the control signal S3. The control circuit 27 is configured to change the impedance of the transmission circuit 28. Due to the change in impedance, the reflection coefficient of the output terminal on the antenna 10 side rotates in the complex plane. The control circuit 27 is configured to change the impedance of the transmission circuit 28 and control the reflection coefficient of the output terminal to rotate in the complex plane. For example, the control circuit 27 is configured to control the impedance of the transmission circuit 28 so as to reduce the USB signal or LSB signal relative to the carrier signal in the reflected signal (hereinafter also referred to as the backscatter signal) to realize a single sideband.

[0020] A method in which the control circuit 27 controls the reflection coefficient of the output terminal of the transmission circuit 28 on the antenna 10 side so as to rotate on the complex plane of the polar chart will be described using the polar chart (polar coordinates) in Fig. 2. Fig. 2 is a diagram for explaining a method in which the control circuit 27 changes the impedance of the transmission circuit 28 and controls so as to rotate the reflection coefficient of the output terminal.

[0021] Figure 2 shows the change in reflection coefficient Γ due to the change in impedance on a polar chart. Impedance is calculated by the following formula (1). In formula (1), Z is impedance, R is resistance, j is an imaginary number, ω is angular frequency, L is inductance, and C is capacitance. Z = R + j(ωL-1 / ωC) (1)

[0022] The reflection coefficient Γ can be expressed by the following equation: Γ=(Z-Z0) / (Z+Z0) (2) Here, Z0 is the impedance of the antenna 10 or the BPF 11.

[0023] The control circuit 27 selects and controls the impedance Z to control the reflection coefficient Γ to rotate around a reference point. The reference point includes the origin, but is not limited to the origin, and includes any point. The closer the reference point is to the origin, the more likely it is that the transmission circuit will obtain a signal that is closer to the ideal. The more the transmission circuit is controlled to rotate in a circle around the reference point, the more likely it is that the signal will be closer to the ideal. In terms of a Smith chart, the lower semicircular area indicates capacitive properties, and the upper half indicates inductive properties. Changes on the real axis represent changes in resistance value.

[0024] The control circuit 27 can selectively control a plurality of impedances included in the transmission circuit 28. For example, the control circuit 27 is configured to control the impedance of the transmission circuit 28 in increments of 45°, i.e., 0°, 45°, 90°, 135°, 180°, −135°, −90°, and −45°. The control circuit 27 is configured to be able to control the impedance of the transmission circuit 28 to rotate discretely by sequentially changing the impedance. The control circuit 27 causes the reflection coefficient Γ to rotate discretely in response to the discrete rotation of the impedance.

[0025] The control circuit 27 is configured to be able to change the impedance in a counterclockwise direction by changing the impedance of the transmission circuit 28. The control circuit 27 is configured to be able to change the reflection coefficient Γ in a counterclockwise direction by rotating the impedance in a counterclockwise direction. When the control of the reflection coefficient is in a counterclockwise direction, the reflected signal for the RF (Radio Frequency) is only a USB (Upper Side Band) signal. When the control is performed so that the reflection coefficient is in a clockwise direction, only a LSB (Lower Side Band) signal is obtained. At that time, the frequency of the reflected signal is a frequency detuned by the rotation speed frequency from the RF signal frequency. Using FIG. 3A, FIG. 3B, and FIG. 3C, some examples of changes in the backscatter signal caused by changing the impedance and controlling the reflection coefficient will be described.

[0026] FIG. 3A is a diagram showing a frequency spectrum for explaining the state of a backscatter signal when the control circuit 27 controls only the resistance component of the impedance and changes the reflection coefficient Γ on the real axis of the polar chart (FIG. 2). The horizontal axis shows frequency, and the vertical axis shows the intensity of the RF signal and the reflected signal. FIG. 3A shows a carrier signal 51, a USB signal 52, and an LSB signal 53. When the resistance component is controlled, the reflection coefficient Γ is controlled to either 0° or 180° on the real axis. When the reflection coefficient Γ is controlled by changing the impedance only with the resistance component, as shown in FIG. 3A, for example, when switching from 0° to 180°, a right-handed signal component and a left-handed signal component are inherent. Due to the existence of signal components of two rotation directions, the USB signal 52 and the LSB signal 53 appear simultaneously, and it is not possible to selectively suppress only one of the signals. As a result, an SSB signal cannot be obtained by controlling only the resistance component.

[0027] FIG. 3B is a diagram showing a frequency spectrum for explaining the change in the backscatter signal when the control circuit 27 changes the inductance / capacitance of the impedance to control the locus of the reflection coefficient Γ to draw a circle. The horizontal axis indicates the frequency, and the vertical axis indicates the intensity of the RF signal and the reflected signal. Based on the formulas (1) and (2), the control circuit 27 can control the impedance to rotate counterclockwise by controlling the value of the inductance. At this time, the impedance rotates counterclockwise, for example, from 0° to 45°, 90°, and 135°. The control circuit 27 can further control the impedance to rotate counterclockwise by controlling the value of the capacitance. At this time, the impedance rotates counterclockwise, for example, from 180° to -135°, -90°, and -45°. As shown in FIG. 3B, the control circuit 27 can reflect the transmitted RF signal so as to suppress the LSB signal 53 by controlling the impedance to rotate counterclockwise. In other words, the control circuit 27 can obtain a backscattered signal converted into SSB in the USB signal 52 by controlling the impedance to rotate counterclockwise.

[0028] FIG. 3C is a diagram showing a frequency spectrum for explaining the change in the backscatter signal when the control circuit 27 changes the capacitance / inductance of the impedance and controls the locus of the reflection coefficient Γ to draw a circle. The horizontal axis indicates the frequency, and the vertical axis indicates the intensity of the RF signal and the reflected signal. Based on the formulas (1) and (2), the control circuit 27 can control the impedance to rotate clockwise by controlling the value of the capacitance. At this time, the impedance rotates clockwise, for example, from 0° to −45°, −90°, and −135°. The control circuit 27 can further control the impedance to rotate clockwise by controlling the value of the inductance. At this time, the impedance rotates clockwise, for example, from 180°, 135°, 90°, and 45°. As shown in FIG. 3C, the control circuit 27 can reflect the transmitted RF signal so as to suppress the USB signal 52 by controlling the impedance to rotate clockwise. In other words, the control circuit 27 can obtain the backscattered signal converted into SSB as the LSB signal 53 by controlling the clockwise rotation of the impedance.

[0029] The transmission circuit 28 is disposed at the front end of the wireless communication device 1. The transmission circuit 28 is a circuit configured to perform backscatter communication in which a transmitted radio wave is reflected as a backscatter signal. The transmission circuit 28 is configured to be connected to the antenna 10. The transmission circuit 28 includes a plurality of impedance circuits each having a different impedance. Each of the plurality of impedance circuits includes a switch element. The switch element is configured to switch the connection of the impedance circuit. The control circuit 27 is configured to switch the connection of the plurality of impedance circuits by controlling the plurality of switch elements. The control circuit 27 is configured to control the impedance of the transmission circuit 28 by controlling the plurality of switch elements.

[0030] [Transmission circuit configuration] The configuration of the transmission circuit according to the first embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining an example of the configuration of the transmission circuit according to the first embodiment.

[0031] 4, transmission circuit 28 includes capacitor circuits 1201 to 1203. Capacitor circuits 1201 to 1203 include signal sources 1401 to 1403 and switch elements 1501 to 1503, respectively. When there is no need to particularly distinguish between switch elements 1501 to 1503, they may be collectively referred to as switch element 150.

[0032] The capacitor circuits 1201 to 1203 are electrically connected to each other by a signal line 101. The signal line 101 is electrically connected to an input / output terminal 102. The capacitor circuits 1201 to 1203 are circuits used when controlling the reflection coefficient to rotate clockwise or counterclockwise between -135° to -90° and between -90° to 0° on a complex plane (polar chart).

[0033] The capacitor circuit 1201 includes a signal source 1401, a switch element 1501, and a capacitor C1. The signal source 1401 indicates a signal source to which a control signal is supplied from the control circuit 27. The signal source 1401 is configured to output a control signal to the switch element 1501 to control the opening and closing operation of the switch element 1501. The switch element 1501 has one input terminal connected to the signal source 1401 and the other input terminal connected to a reference potential. The reference potential will be described as being ground, but the present disclosure is not limited thereto. The switch element 1501 is configured to switch between a closed state and an open state according to a control signal from the signal source 1401.

[0034] The signal line 101 is electrically connected to one end of the switch element 1501, and one end of the capacitor C1 is electrically connected to the other end. The other end of the capacitor C1 is connected to a reference potential. In this case, the switch element 1501 is configured to electrically connect the signal line 101 and the capacitor C1 when in a closed state. The switch element 1501 is configured to electrically separate the signal line 101 and the capacitor C1 when in an open state. When the signal line 101 and the capacitor C1 are electrically connected, the capacitance of the capacitor C1 is added to the impedance of the transmission circuit 28. That is, the reactance component of the impedance of the transmission circuit 28 changes when the capacitance of the capacitor C1 is added.

[0035] The capacitor circuit 1202 includes a signal source 1402, a switch element 1502, and a capacitor C2. The signal source 1402 indicates a signal source to which a control signal is supplied from the control circuit 27. The signal source 1402 is configured to output a control signal to the switch element 1502 to control the opening and closing operation of the switch element 1502. The switch element 1502 has one input terminal connected to the signal source 1402 and the other input terminal connected to a reference potential. The reference potential will be described as being ground, but the present disclosure is not limited thereto. The switch element 1502 is configured to switch between a closed state and an open state according to a control signal from the signal source 1402.

[0036] The signal line 101 is electrically connected to one end of the switch element 1502, and one end of the capacitor C2 is electrically connected to the other end. The other end of the capacitor C2 is connected to a reference potential. In this case, the switch element 1502 is configured to electrically connect the signal line 101 and the capacitor C2 when in a closed state. The switch element 1502 is configured to electrically separate the signal line 101 and the capacitor C2 when in an open state. When the signal line 101 and the capacitor C2 are electrically connected, the capacitance of the capacitor C2 is added to the impedance of the transmission circuit 28. That is, the reactance component of the impedance of the transmission circuit 28 changes when the capacitance of the capacitor C2 is added.

[0037] The capacitor circuit 1203 includes a signal source 1403, a switch element 1503, and a capacitor C3. The signal source 1403 indicates a signal source to which a control signal is supplied from the control circuit 27. The signal source 1403 is configured to output a control signal to the switch element 1503 to control the opening and closing operation of the switch element 1503. The switch element 1503 has one input terminal connected to the signal source 1403 and the other input terminal connected to a reference potential. Although the reference potential is described as being the ground, the present disclosure is not limited to this. The switch element 1503 is configured to switch between a closed state and an open state according to a control signal from the signal source 1403. Note that one or more of the capacitor circuits among the capacitor circuits 1201 to 1203 may include one or more electric elements among a plurality of inductor elements and a plurality of resistor elements.

[0038] The signal line 101 is electrically connected to one end of the switch element 1503, and one end of the capacitor C3 is electrically connected to the other end. The other end of the capacitor C3 is connected to a reference potential. In this case, the switch element 1503 is configured to electrically connect the signal line 101 and the capacitor C3 when in a closed state. The switch element 1503 is configured to electrically separate the signal line 101 and the capacitor C3 when in an open state. When the signal line 101 and the capacitor C3 are electrically connected, the capacitance of the capacitor C3 is added to the impedance of the transmission circuit 28. That is, the reactance component of the impedance of the transmission circuit 28 changes when the capacitance of the capacitor C3 is added.

[0039] The control circuit 27 can control the impedance of the transmission circuit 28 to rotate on the complex plane by controlling the open / closed states of each of the switch elements 1501 to 1503. The control circuit 27 can control the impedance of the transmission circuit 28 to rotate on the complex plane by closing any one of the switch elements 1501 to 1503 or opening all of the switch elements. The control circuit 27 may be capable of controlling the impedance of the transmission circuit 28 to rotate on the complex plane by opening a plurality of the switch elements 1501 to 1503.

[0040] When all the switch elements 1501 to 1503 are in an open state, the impedance of the transmission circuit 28 is located at 0° on the complex plane. When only the switch element 1501 is in a closed state, the impedance of the transmission circuit 28 is located at -45°. When only the switch element 1502 is in a closed state, the impedance of the transmission circuit 28 is located at -90°. When only the switch element 1503 is in a closed state, the impedance of the transmission circuit 28 is located at -135°. That is, the control circuit 27 can control the position of the impedance at four points on the complex plane by controlling the switch elements 1501 to 1503. The capacitor circuits 1201 to 1203 can be configured to rotate and control the impedance between -135° to -90° and between -90° to 0°. The control circuit 27 is configured to sequentially close only one of the switch elements 1501, 1502, and 1503 to perform clockwise rotation control of the impedance of the transmission circuit 28. The control circuit 27 is configured to sequentially close only one of the switch elements 1503, 1502, and 1501 to perform counterclockwise rotation control of the impedance of the transmission circuit 28.

[0041] A method for performing rotation control of the impedance on a complex plane in the transmission circuit according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining a method for performing rotation control of the reflection coefficient on a complex plane according to the first embodiment.

[0042] 5, the transmission circuit 28 (capacitor circuits 1201 to 1203) shown in FIG 4 may be integrated into an integrated circuit as a capacitor IC 160. In this case, the capacitor IC 160 is configured to be connected to either the phase shifter 170 or the signal line 180 by switching the changeover switch element 190 by the changeover switch control circuit 200.

[0043] The phase shifter 170 includes a capacitor, an inductor, and another capacitor (not shown). The phase shifter 170 is a phase shifter that shifts the phase of an input signal by 90° and outputs the signal.

[0044] The changeover switch control circuit 200 controls the changeover switch element 190 to connect the capacitor IC160 and the signal line 180 when controlling the impedance to rotate between 0° to −90° and between −90° to −135°.

[0045] When controlling the impedance to rotate between 45° to 90° and between 90° to 180°, the changeover switch control circuit 200 controls the changeover switch element 190 to connect the capacitor IC160 and the phase shifter 170. By connecting the capacitor IC160 and the phase shifter 170, the position of the impedance on the complex plane can be controlled at eight points. In this way, by forming the device into an integrated circuit, a configuration advantageous for miniaturization can be achieved. In this embodiment, the control circuit 27 and the changeover switch control circuit 200 may be integrally configured.

[0046] [Second embodiment] The configuration of the wireless communication device according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a block diagram showing an example of the configuration of the wireless communication device according to the second embodiment.

[0047] 6, the wireless communication device 1A is different from the wireless communication device 1 shown in FIG 1 in that the control device 30A is configured to output a control signal S7 to the transmission circuit 28A of the RFBS device 20A. The control signal S7 is a control signal used to control a compensation circuit, which will be described later, that compensates for the capacitance value and resistance value of the capacitor circuit 120.

[0048] [Transmission circuit configuration] The configuration of the transmission circuit according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining an example of the configuration of the transmission circuit according to the second embodiment.

[0049] 7, transmission circuit 28A differs from transmission circuit 28 shown in Fig. 4 in that capacitor circuits 120A1 to 120A3 include compensation circuits 3001 to 3003 instead of switch elements 1501 to 1503 and capacitors C1 to C3, respectively. When there is no need to particularly distinguish between compensation circuits 3001 to 3003, they may be collectively referred to as compensation circuit 300.

[0050] The compensation circuit 300 is configured to add a capacitance value and a resistance value to the capacitor circuit 120A. The compensation circuit 300 is configured so that the capacitance value and the resistance value can be changed by a control signal from the control device 30A.

[0051] [Compensation circuit configuration] The configuration of the compensation circuit according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram for explaining an example of the configuration of the compensation circuit according to the second embodiment.

[0052] As shown in FIG. 8, the compensation circuit 300 includes a capacitance selector 310, a resistance selector 320, an AND gate circuit 331 to an AND gate circuit 338, capacitance transistors 341 to 348, capacitors 351 to 358, and compensation transistors 361 to 368. When it is not necessary to distinguish between the AND gate circuit 331 to the AND gate circuit 338, they may be collectively referred to as an AND gate circuit 330. When it is not necessary to distinguish between the capacitance transistors 341 to 348, they may be collectively referred to as a capacitance transistor 340. When it is not necessary to distinguish between the capacitors 351 to 358, they may be collectively referred to as a capacitor 350. When it is not necessary to distinguish between the compensation transistors 361 to 368, they may be collectively referred to as a compensation transistor 360.

[0053] The capacitance selector 310 includes a first input terminal 311, a second input terminal 312, and a third input terminal 313. The capacitance selector 310 is configured so that a control signal S7 from the control device 30A is input to the first input terminal 311 to the third input terminal 313. That is, the capacitance selector 310 is a 3-bit selector. In the second embodiment, the capacitance selector 310 is described as being a 3-bit selector, but the present disclosure is not limited to this. The number of bits of the capacitance selector 310 may be any number.

[0054] The capacitance selector 310 includes a first output terminal to an eighth output terminal. The first output terminal to the eighth output terminal of the capacitance selector 310 are electrically connected to one input terminal of the AND gate circuit 331 to the AND gate circuit 338, respectively. The capacitance selector 310 is configured to selectively output a control signal to one input terminal of the AND gate circuit 331 to the AND gate circuit 338 in accordance with a control signal S7 input to the first input terminal 311 to the third input terminal 313.

[0055] The resistor selector 320 includes a first input terminal 321, a second input terminal 322, and a third input terminal 323. The resistor selector 320 is configured so that a control signal S7 from the control device 30A is input to the first input terminal 321 to the third input terminal 323. That is, the resistor selector 320 is a 3-bit selector. In the second embodiment, the resistor selector 320 is described as being a 3-bit selector, but the present disclosure is not limited to this. The number of bits of the resistor selector 320 may be any number.

[0056] The AND gate circuit 331 to the AND gate circuit 338 have one input terminal electrically connected to the first output terminal to the eighth output terminal of the capacitance selector 310, respectively. The AND gate circuit 331 to the AND gate circuit 338 have the other input terminal electrically connected to the input terminal 301. The input terminal 301 is configured so that a control signal is input from the signal source 140. The AND gate circuit 331 to the AND gate circuit 338 have output terminals electrically connected to the gate terminals of the capacitance transistors 341 to 348, respectively.

[0057] The AND gate circuit 330 is configured to output a high-level output signal when a high-level control signal is input to both one input terminal and the other input terminal. The capacitance selector 310 is configured to constantly output a high-level control signal to at least one input terminal of the AND gate circuit 331. The signal source 140 is configured to output a control signal to the other input terminal of the AND gate circuit 330.

[0058] The capacitance transistors 341 to 348 are, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), but are not limited to this.

[0059] The gate terminals of the capacitance transistors 341 to 348 are electrically connected to the output terminals of the AND gate circuits 331 to 338, respectively. The drain terminals of the capacitance transistors 341 to 348 are electrically connected to the output terminal 302, respectively. The source terminals of the capacitance transistors 341 to 348 are electrically connected to one terminal of the capacitors 351 to 358, respectively.

[0060] The capacitance transistor 340 switches from an open state to a closed state when a high-level output signal is input to the gate terminal from the AND gate circuit 330. When the capacitance transistor 340 switches from an open state to a closed state, the capacitor 350 is electrically connected to the output terminal 302. As a result, the capacitance of the capacitor 350 is added to the capacitor circuit 120A.

[0061] One terminal of each of the capacitors 351 to 358 is electrically connected to the source terminal of the capacitance transistor 341 to 348. The other terminal of each of the capacitors 351 to 358 is electrically connected to the drain terminal of the compensation transistor 361 to 368.

[0062] For example, when the target capacitance value of the capacitor circuit 120A is C [pF (picofarad)], the capacitance value of the capacitor 351 may be 0.7 C [pF]. The capacitance values ​​of the capacitors 352 to 358 may be 0.1 C [pF].

[0063] The compensation circuit 300 is configured to selectively add capacitance values ​​of 0.7C to 1.4C to the transmission circuit 28A in increments of 0.1C from a reference capacitance value of 0.7C by sequentially controlling the capacitance transistors 341 to 348 to be turned on. Specifically, when only the capacitance transistor 341 is in a closed state, 0.7C is added to the transmission circuit 28A, and when the capacitance transistors 341 and 342 are in an on state, 0.8C is added to the transmission circuit 28A. That is, in the second embodiment, the capacitance value to be added to the capacitor circuit 120A can be arbitrarily selected between 0.7C and 1.4C.

[0064] The compensation transistors 361 to 368 are configured such that their gate terminals are electrically connected to the first to eighth output terminals of the resistor selector 320, respectively. The compensation transistors 361 to 368 are configured such that their drain terminals are electrically connected to the other terminals of the capacitors 351 to 358, respectively. The compensation transistors 361 to 368 are configured such that their source terminals are electrically connected to a reference potential. The reference potential is, for example, but is not limited to, the ground.

[0065] The compensation transistor 360 switches from an open state to a closed state when a high-level output signal is input to the gate signal from the resistance selector 320. When the compensation transistor 360 switches from an open state to a closed state, the parasitic resistance of the compensation transistor 360 is added to the capacitance transistor 340. In other words, the compensation circuit 300 is configured to selectively add the parasitic resistances of the compensation transistors 361 to 368 to the capacitance transistors 341 to 348, respectively.

[0066] The capacitance transistors 341 to 348 each have a parasitic resistance. It is expected that the characteristics of the transmission circuit 28A may change depending on the variation in the resistance values ​​of the parasitic resistances of the capacitance transistors 341 to 348. Therefore, by selectively adding the resistance values ​​of the parasitic resistances of the compensation transistors 361 to 368 depending on the resistance values ​​of the parasitic resistances of the capacitance transistors 341 to 348, it is possible to compensate for the influence of a particular variation.

[0067] The method of controlling the rotation of impedance according to the second embodiment is the same as the method according to the first embodiment, and therefore a description thereof will be omitted.

[0068] As described above, in the second embodiment, a capacitance value and a resistance value can be selectively added to the transmission circuit 28A. This makes it possible to compensate for the influence on the characteristics caused by the variations in the capacitance value and resistance value of the capacitor circuit 120A.

[0069] [Third embodiment] The configuration of the wireless communication device according to the third embodiment will be described with reference to Fig. 9. Fig. 9 is a block diagram showing an example of the configuration of the wireless communication device according to the third embodiment.

[0070] 9, the wireless communication device 1B differs from the wireless communication device 1 shown in Fig. 1 in that it includes a composite transmission circuit 400 and that a control device 30B is configured to output a control signal S8 to the composite transmission circuit 400. The composite transmission circuit 400 is configured to include a plurality of transmission circuits.

[0071] [Complex transmission circuit] The configuration of the composite transmission circuit according to the third embodiment will be described with reference to Fig. 10. Fig. 10 is a diagram for explaining an example of the configuration of the composite transmission circuit according to the third embodiment.

[0072] As shown in FIG. 10, the composite transmission circuit 400 includes a first transmission circuit 28B, a second transmission circuit 28C, a third transmission circuit 28D, and a switch circuit 410.

[0073] The first transmission circuit 28B includes capacitor circuits 120B1 to 120B3. The capacitor circuits 120B1 to 120B3 include signal sources 140B1 to 140B3, switch elements 150B1 to 150B3, and capacitors C11B to C13B, respectively. The capacitor circuits 120B1 to 120B3 are electrically connected to each other by a signal line 101B. The signal line 101B is electrically connected to an input / output terminal 102B. The specific configurations of the capacitor circuits 120B1 to 120B3 are similar to those of the transmission circuit 28 shown in FIG. 4, and therefore will not be described.

[0074] The second transmission circuit 28C includes capacitor circuits 120C1 to 120C3. The capacitor circuits 120C1 to 120C3 include signal sources 140C1 to 140C3, switch elements 150C1 to 150C3, and capacitors C11C to C13C, respectively. The capacitor circuits 120C1 to 120C3 are electrically connected to each other by a signal line 101C. The signal line 101C is electrically connected to an input / output terminal 102C. The specific configurations of the capacitor circuits 120C1 to 120C3 are similar to those of the transmission circuit 28 shown in FIG. 4, and therefore will not be described.

[0075] The third transmission circuit 28D includes capacitor circuits 120D1 to 120D3. The capacitor circuits 120D1 to 120D3 include signal sources 140D1 to 140D3, switch elements 150D1 to 150D3, and capacitors C11D to C13D, respectively. The capacitor circuits 120D1 to 120D3 are electrically connected to each other by a signal line 101D. The signal line 101D is electrically connected to an input / output terminal 102D. The specific configurations of the capacitor circuits 120D1 to 120D3 are similar to those of the transmission circuit 28 shown in FIG. 4, and therefore will not be described.

[0076] The first transmission circuit 28B, the second transmission circuit 28C, and the third transmission circuit 28D each have different characteristics with respect to capacitance and resistance.

[0077] The first transmission circuit 28B is, for example, a transmission circuit having a characteristic of a center value in design values. Specifically, the first transmission circuit 28B is a transmission circuit having a capacitance value, a resistance value, and a characteristic value of the switch element 150B (transistor) having a characteristic of a center value in design values. The center value characteristic is also called a first characteristic.

[0078] The second transmission circuit 28C is, for example, a transmission circuit having characteristics of the upper limit value of the design value. Specifically, the second transmission circuit 28C is a transmission circuit in which the capacitance value, resistance value, and characteristic value of the switch element 150C (transistor) have characteristics of the upper limit value of the design value. The characteristics of the upper limit value are also called second characteristics.

[0079] The third transmission circuit 28D is, for example, a transmission circuit having characteristics of the lower limit of the design value. Specifically, the third transmission circuit 28D is a transmission circuit in which the capacitance value, resistance value, and characteristic value of the switch element 150D (transistor) have characteristics of the lower limit of the design value. The characteristics of the lower limit are also called the third characteristics.

[0080] The switch circuit 410 includes an input / output terminal 411. The input / output terminal 411 is electrically connected to the high-frequency switch 21 shown in FIG.

[0081] The switch circuit 410 is configured to electrically connect any one of the input / output terminal 102B, the input / output terminal 102C, and the input / output terminal 102D to the input / output terminal 411. That is, the switch circuit 410 is configured to electrically connect any one of the first transmission circuit 28B, the second transmission circuit 28C, and the third transmission circuit 28D to the antenna 10. The switch circuit 410 is configured to electrically connect any one of the first transmission circuit 28B, the second transmission circuit 28C, and the third transmission circuit 28D to the antenna 10 in accordance with, for example, a control signal S8 from the control device 30B. The control device 30B is a type of switch control unit.

[0082] The control device 30B performs control in accordance with the overall characteristics of the wireless communication device 1B so as to electrically connect any one of the first transmission circuit 28B, the second transmission circuit 28C, and the third transmission circuit 28D to the antenna 10. The control device 30B may dynamically change the transmission circuit to be electrically connected to the high-frequency switch 21 after electrically connecting any one of the first transmission circuit 28B, the second transmission circuit 28C, and the third transmission circuit 28D to the antenna 10.

[0083] In the third embodiment, the composite transmission circuit 400 has been described as including three transmission circuits, but the present disclosure is not limited thereto. The composite transmission circuit 400 may include, for example, two transmission circuits, one having a center value of the design value and one having an upper limit value or a lower limit value. The composite transmission circuit 400 may include, for example, two transmission circuits, one having an upper limit value and one having a lower limit value of the design value. The composite transmission circuit 400 may include, for example, 27 transmission circuits designed with combinations of the upper limit value, center value, and lower limit value of the characteristic values ​​of the capacitance value, resistance value, and switch element.

[0084] A method for performing rotation control of the impedance on a complex plane in the transmission circuit according to the third embodiment will be described with reference to Fig. 11. Fig. 11 is a diagram for explaining a method for performing rotation control of the reflection coefficient on a complex plane according to the third embodiment.

[0085] As shown in Fig. 11, the composite transmission circuit 400 shown in Fig. 10 may be integrated into a composite capacitor IC500 for use. In this case, the composite capacitor IC500 is configured to be connected to either the phase shifter 170 or the signal line 180 by switching the changeover switch element 190 by the changeover switch control circuit 200.

[0086] The multiple transmission circuits included in the composite capacitor IC500 are configured such that any one of the multiple transmission circuits is electrically connected to the input / output terminal 104 in response to a control signal S8 from the control device 30B, for example.

[0087] The method of controlling the rotation of impedance according to the third embodiment is the same as the method according to the first embodiment, and therefore a description thereof will be omitted.

[0088] As described above, the third embodiment can perform control so that one of the first transmission circuit 28B, the second transmission circuit 28C, and the third transmission circuit 28D, each of which has different characteristics, is electrically connected to the antenna 10 in accordance with the overall characteristics of the wireless communication device 1B. This makes it possible for the third embodiment to compensate for variations in characteristics during manufacturing of the wireless communication device 1B.

[0089] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. The above-mentioned components include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-mentioned components can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the gist of the above-mentioned embodiments. [Explanation of symbols]

[0090] 1. Wireless communication devices 10 Antennas 11 BPF 20 RFBS Devices 21 High Frequency Switch 22 Amplifier 23 Demodulation section 24 Oscillator 25,26 LPF 27 Control circuit 28 Transmission Circuit 30 Control device 40 Sensors 120 Capacitor Circuit 140 Signal source 150 Switching element 160 Capacitor IC 170 Phase shifter 200 Changeover switch control circuit 300 compensation circuit 310 Capacity Selector 320 Resistor Selector 330 AND Gate Circuit 340 Capacitive Transistor 350 Capacitor 360 Compensation transistor

Claims

1. A transmission circuit configured to be connected to an antenna, The transmission circuit includes: A plurality of impedance circuits each having a different impedance; a plurality of switch elements, any one of which is connected to each of the plurality of impedance circuits; a compensation circuit connected to each of the plurality of switch elements and selectively adding a capacitance value and a resistance value to the transmission circuit; A control circuit configured to control opening and closing of the plurality of switch elements, The control circuit is configured to selectively change the opening and closing of the plurality of switch elements to control so as to rotate the reflection coefficient of the output terminal on the antenna side in a complex plane.

2. 2. The transmission circuit according to claim 1, The compensation circuit includes a plurality of capacitors selectively connected to the impedance circuit, and a plurality of resistive elements selectively connected to the impedance circuit.

3. 3. The transmission circuit according to claim 2, The control circuit is configured to selectively connect the plurality of capacitors and the resistance element to the impedance circuit according to a capacitance value and a resistance value of the transmission circuit.

4. 4. The transmission circuit according to claim 1, A transmission circuit, wherein the plurality of impedance circuits include a plurality of inductor circuits configured to adjust an inductance among reactance components of impedance.

5. 4. The transmission circuit according to claim 1, A transmission circuit, wherein the plurality of impedance circuits include a plurality of capacitor circuits configured to adjust a capacitance among reactance components of impedance.

6. 1. A composite transmission circuit configured to couple to an antenna, comprising: The composite transmission circuit includes: a first transmission circuit having a first characteristic related to a capacitance value and a resistance value; a second transmission circuit having a second characteristic different from the first characteristic with respect to a capacitance value and a resistance value; a third transmission circuit having a third characteristic different from the first characteristic and the second characteristic with respect to a capacitance value and a resistance value; a switch control circuit configured to selectively connect the first transmission circuit, the second transmission circuit, and the third transmission circuit to the antenna; Each of the first transmission circuit, the second transmission circuit, and the third transmission circuit is A plurality of impedance circuits each having a different impedance; a plurality of switch elements, any one of which is connected to each of the plurality of impedance circuits; A control circuit configured to control opening and closing of the plurality of switch elements, The control circuit is configured to selectively change the opening and closing of the plurality of switch elements to control the reflection coefficient of the output terminal on the antenna side to rotate in a complex plane. Composite transmission circuit.

7. 7. The composite transmission circuit according to claim 6, the switch control circuit is configured to selectively connect the first transmission circuit, the second transmission circuit, and the third transmission circuit to the antenna depending on the degree of variation of the first characteristic, the second characteristic, and the third characteristic.

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