Communication device, communication system, and imaging system

Abstract

This communication device includes a baseband signal processing unit, an in-phase signal processing unit and a quadrature signal processing unit that modulate a data signal input from the baseband signal processing unit, and a balanced antenna provided with a first port and a second port. The communication device is provided with a first path that connects the baseband signal processing unit and the first port via the in-phase signal processing unit, and a second path that connects the baseband signal processing unit and the second port via the quadrature signal processing unit. The first port and the second port have opposite polarities. The communication device further includes a phase notification unit that generates a notification signal, in order to output the notification signal indicating phase information corresponding to a phase difference between an in-phase signal to be output via the first path and a quadrature signal to be output via the second path.

Description

Communication device, communication system, and imaging system

[0001] The present disclosure relates to a communication device, a communication system, and an imaging system.

[0002] In recent years, the 3GPP (registered trademark) (3rd Generation Partnership Project) has been formulating specifications for next-generation standards (beyond 5G and 6G). The terahertz wave band has been raised as a candidate for a radio frequency resource in 6G. Terahertz waves are electromagnetic waves having a frequency range of 10 GHz to 100 THz. Patent Document 1 discloses a method for oscillating electromagnetic waves in the terahertz wave band.

[0003] Japanese Patent Application Laid-Open No. 2017-201779

[0004] Patent Document 1 describes the generation of terahertz waves, but does not describe a configuration for use in communications.

[0005] An object of the present disclosure is to provide a technology that is advantageous for communication using high-frequency electromagnetic waves such as terahertz waves.

[0006] In view of the above problems, a communication device according to an embodiment of the present disclosure is a communication device including a baseband signal processing unit, an in-phase signal processing unit and a quadrature signal processing unit that modulate a data signal input from the baseband signal processing unit, and a balanced antenna having a first port and a second port, wherein the communication device includes a first path that connects the baseband signal processing unit and the first port via the in-phase signal processing unit, and a second path that connects the baseband signal processing unit and the second port via the quadrature signal processing unit, the first port and the second port having opposite polarities to each other, and further includes a phase notification unit that generates a notification signal to output a notification signal indicating phase information corresponding to a phase difference between an in-phase signal output via the first path and a quadrature signal output via the second path.

[0007] According to the present disclosure, it is possible to provide a technology that is advantageous for communication using high-frequency electromagnetic waves such as terahertz waves.

[0008] Other features and advantages of the present disclosure will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar components are designated by the same reference numerals.

[0009] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments of the present disclosure, and are used, together with the description, to explain the principles of the present disclosure. A diagram showing an example of the configuration of a communication device according to an embodiment. A diagram showing an example of the configuration of a communication device according to an embodiment. A diagram showing an example of the configuration of a wireless communication unit of the communication device of FIG. 1. A diagram showing an example of the configuration of a wireless communication unit of the communication device of FIG. 1. A diagram showing an example of the configuration of a wireless communication unit of the communication device of FIG. 1. A diagram showing an example of the configuration of a wireless communication unit of the communication device of FIG. 1. A diagram showing an example of the configuration of an example of a transmission waveform of the communication device of FIG. 1. A diagram showing an example of the transmission waveform of the communication device of FIG. 1. A diagram showing an example of the configuration of a modulation unit of the communication device of FIG. 1. A diagram showing an example of the configuration of a modulation unit of the communication device of FIG. 1. A diagram showing an example of the configuration of a wireless communication unit of the communication device of FIG. 1. A diagram showing an example of the configuration of a wireless communication unit of the communication device of FIG. 1. A diagram showing an example of the reception waveform of the communication device of FIG. 1. A diagram showing an example of the reception waveform of the communication device of FIG. 1. A diagram showing an example of the reception waveform of the communication device of FIG. 1. A diagram showing an example of the waveform of a notification signal of the communication device of FIG. 1. A diagram showing an example of the waveform of a notification signal of the communication device of FIG. 1. A diagram showing an example of the configuration of a demodulation unit of the communication device of FIG. 1. FIG. 2 is a diagram showing an example of the configuration of a demodulation unit of the communication device of Fig. 1. FIG. 3 is a diagram showing an example of the configuration of a wireless communication unit of the communication device of Fig. 1. FIG. 4 is a diagram showing an example of the configuration of a wireless communication unit of the communication device of Fig. 1. FIG. 5 is a diagram showing an example of the configuration of a wireless communication unit of the communication device of Fig. 1. FIG. 6 is a diagram showing an example of the configuration of a wireless communication unit of the communication device of Fig. 1. FIG. 7 is a diagram showing an example of the configuration of an imaging system using the communication device of Fig. 1. FIG. 8 is a diagram showing an example of the configuration of a communication system using the communication device of Fig. 1.

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claims. Although multiple features are described in the embodiments, not all of these multiple features are required, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0011] A communication device according to an embodiment of the present disclosure will be described with reference to Figures 1A and 1B to 13A to 13C. The configuration of functional blocks of the communication device described below is merely an example. Some (or in some cases all) of the functional blocks described may be replaced with other functional blocks that perform similar functions, some functional blocks may be omitted, or additional functional blocks may be added. Furthermore, one functional block described below may be divided into multiple functional blocks, or multiple functional blocks may be integrated into one functional block.

[0012] FIG. 1A is a functional block diagram showing an example configuration of a communication device 101 according to this embodiment. FIG. 1B is a functional block diagram showing an example configuration of a communication device 106 according to this embodiment. The communication device 101 may include a control unit 102, a storage unit 103, an application unit 104, and a wireless communication unit 105. The control unit 102 controls each component arranged in the communication device 101. The storage unit 103 stores data used in the communication device 101. The application unit 104 executes application software using the data stored in the storage unit 103. The application software may be, for example, video viewing software or game software. The wireless communication unit 105 wirelessly communicates data from the storage unit 103 and data used by the application unit 104 with an external device. The wireless communication unit 105 performs modulation processing to superimpose digital data onto an analog signal and transmits the modulated analog signal into space as electromagnetic waves. For example, the wireless communication may be public wireless communication such as 4G, 5G, or 6G, or a standard wireless communication such as WLAN, Bluetooth (registered trademark), or Zigbee. The wireless communication may also be a proprietary wireless communication based on a non-standard wireless protocol. The communication device 101 may also be referred to as a transmitting device.

[0013] The communication device 106 may include a control unit 107, a memory unit 108, an application unit 109, and a wireless communication unit 110. The control unit 107, the memory unit 108, and the application unit 109 may have the same functions as the control unit 102, the memory unit 103, and the application unit 104, respectively. For example, the control unit 107, the memory unit 108, and the application unit 109 may have the same configuration as the control unit 102, the memory unit 103, and the application unit 104, respectively. The wireless communication unit 110 receives electromagnetic waves in space and performs demodulation processing to extract digital data from the analog signals of the electromagnetic waves. The communication device 106 may also be referred to as a receiving device. The communication device 101 and the communication device 106 may constitute a communication system by transmitting and receiving data.

[0014] Next, the configuration of the wireless communication unit 105 during transmission will be described using Figures 2A to 2C. Figure 2A is a block diagram showing an example configuration of the wireless communication unit 105. The wireless communication unit 105 can include a baseband signal processing unit 201, an in-phase signal processing unit 202, a quadrature signal processing unit 203, a balanced antenna 204, and a phase notification unit 205. The in-phase signal processing unit 202 and the quadrature signal processing unit 203 configure a modulation unit 210.

[0015] The balanced antenna 204 has a positive port 206 and a negative port 207 with opposite polarities. As an example of the balanced antenna 204, a patch antenna is shown in FIG. 2B , and the voltage distribution in the vertical direction of the patch antenna shown in FIG. 2B is shown in FIG. 2C . The patch antenna, which is the balanced antenna 204, has a positive voltage region 212 in the upper half and a negative voltage region 213 in the lower half, with a center line 211 as the boundary. The balanced antenna 204 has a positive power supply port (positive port 206) in the positive voltage region 212 and a negative power supply port (negative port 207) in the negative voltage region 213. Because the positive and negative polarities of these voltages fluctuate over time, the positive and negative polarities of the above voltages and ports indicate the voltage relationship at a certain point in time for convenience. In other words, at a certain time, a negative voltage may be applied to the positive port 206 and a positive voltage may be applied to the negative port 207.

[0016] Here, in practical and design terms, it is easier to use if the positive port 206 and the negative port 207 are out of phase. However, this is not limiting. Here, "the positive port 206 and the negative port 207 are out of phase" does not only mean that the phase difference between the positive port 206 and the negative port 207 is exactly 180 degrees, but also includes cases where the phase difference is between 175 degrees and 185 degrees, such as 178 degrees or 183 degrees. Even in such cases, the effects of this embodiment can be obtained. Furthermore, "the positive port 206 and the negative port 207 are out of phase" means that the phase of the signal at the positive port 206 and the phase of the signal at the negative port 207 are in an inverse relationship with respect to the baseband signal.

[0017] The in-phase signal processing unit 202 and the quadrature signal processing unit 203 arranged in the modulation unit 210 modulate the data signal input from the baseband signal processing unit 201. The in-phase signal processing unit 202 is connected to the baseband signal processing unit 201 and the positive port 206 of the balanced antenna 204. The in-phase signal processing unit 202 is also connected to the phase notification unit 205. The quadrature signal processing unit 203 is connected to the baseband signal processing unit 201 and the negative port 207 of the balanced antenna 204. The phase notification unit 205 is connected to the in-phase signal processing unit 202 and the baseband signal processing unit 201. Here, the path connecting the baseband signal processing unit 201 and the positive port 206 of the balanced antenna 204 via the in-phase signal processing unit 202 is referred to as path 208. Similarly, the path connecting the baseband signal processing unit 201 and the negative port 207 of the balanced antenna 204 via the quadrature signal processing unit 203 is referred to as path 209.

[0018] Next, the signal processing of the wireless communication unit 105 will be described using signal waveforms generated in the baseband signal processing unit 201, the in-phase signal processing unit 202, and the quadrature signal processing unit 203. Waveforms of the transmission signals at positions (i) and (ii) shown in Fig. 2A are shown in Figs. 3B and 3C, respectively.

[0019] During transmission, digital data stored in the memory unit 103 and digital data calculated by the application unit 104 are wirelessly transmitted from the wireless communication unit 105 to an external device (e.g., a receiving device) of the communication device 101. This digital data is called a baseband signal and has, for example, a signal waveform 301 as shown in FIG. 3A. The signal waveform 301 may be a positive logic, double-current signal sequence in which a negative amplitude -A is 0 and a positive amplitude A is 1, and in the example shown in FIG. 3A, it is [10010011]. Hereinafter, an example of a positive logic, double-current signal sequence will be described, but other methods such as negative logic and a single-current signal sequence may also be used. Furthermore, in the following description, Quadrature Phase Shift Keying (QPSK) will be used as an example of modulation and demodulation for digital communication. However, this is not limited to this, and other methods may also be used.

[0020] In QPSK modulation and demodulation, the baseband signal is serial-to-parallel converted by two bits at a time by the baseband signal processing unit 201. That is, [10010011] of the signal waveform 301 is converted to

[1001] and

[0101] , and further, in this case,

[1001] is assigned to the in-phase (I) component (in-phase signal) and

[0101] is assigned to the quadrature (Q) component (quadrature signal) in the NRZ format. Figure 3B shows a signal waveform 302 of the in-phase signal before modulation and a signal waveform 303 of the quadrature signal before modulation at the position (i) shown in Figure 2A.

[0021] The in-phase signal is sent to in-phase signal processing section 202 and modulated. If the digital signal is 1 and the phase of the carrier wave is 0 degrees, and if the digital signal is 0 and the phase of the carrier wave is 180 degrees, then

[1001] of signal waveform 302 becomes an analog signal mixed with the carrier wave, as shown in signal waveform 304 in FIG. 3C. Similarly, the quadrature signal is modulated by quadrature signal processing section 203 and becomes an analog signal with signal waveform 305 as shown in FIG. 3C. Here, the carrier waves mixed into the in-phase signal and quadrature signal are cosine wave cos(2πft) and sine wave sin(2πft), which are orthogonal to each other, as will be described later.

[0022] The modulated in-phase signal (signal waveform 304) and quadrature signal (signal waveform 305) are sent to the positive port 206 and negative port 207 of the balanced antenna 204, respectively, via position (ii) shown in FIG. 2A , where they are combined and radiated from the balanced antenna 204. The quadrature signal fed to the negative port 207 is input to the negative voltage region 213 in the balanced antenna 204, and its phase is inverted in the positive voltage region 212. Therefore, the in-phase signal and the quadrature signal with the inverted phase are combined in the balanced antenna 204. The combined signal has a signal waveform 306 as shown in FIG. 3D . In other words, the combined signal radiated from the balanced antenna 204 has a signal waveform 306 having the same shape as the signal waveform obtained by combining the in-phase signal (signal waveform 304) mixed with an in-phase carrier wave and the quadrature signal (signal waveform 305) mixed with a quadrature carrier wave, but with the inverted phase.

[0023] Generally, a cosine wave cos(2πft) and a sine wave sin(2πft) are used as the in-phase carrier and quadrature carrier waves mixed into the in-phase and quadrature signals, respectively. f is the frequency of the carrier wave, and t is a time variable. Here, orthogonality means that the integral of the product of the function f(t) and the function g(t) over the entire interval is 0, i.e., the following equation 1 is satisfied:

[0024]

[0025] The cosine wave and sine wave described above satisfy equation (1). By mixing a signal with such quadrature waves and transmitting the signal, it is possible to extract the mixed signal upon reception. For example, if the in-phase signal is +1 and the quadrature signal is -1, the combined signal is cos(2πft) - sin(2πft). To extract the in-phase signal during demodulation on the receiving side, the combined signal is multiplied by the cosine wave cos(2πft) and integrated over the entire interval, as shown in equation (2). The carrier wave is a wave that repeats with a period T, and the integral over the entire interval is equal to the period T. As a result of calculating equation (2), +½, i.e., half of the in-phase signal component, can be extracted as the in-phase signal.

[0026] Similarly, the negative phase signal can be extracted by multiplying the combined signal by a sine wave sin(2πft) as in equation (3) and integrating over the entire interval, thereby extracting −½, which is half of the negative phase signal component.

[0027]

[0028] 4 and 5 show exemplary configurations for transmission, i.e., modulation, in the modulation unit 210. In the configuration shown in FIG. 4, the modulation unit 210 includes a carrier wave generation unit 400 for generating a carrier wave. The carrier wave generation unit 400 includes a carrier wave generation unit 401 and a phase shift unit 403. The in-phase signal input from the baseband signal processing unit 201 to the in-phase signal processing unit 202 via path 208 is mixed with the carrier wave generated by the carrier wave generation unit 401 and modulated. As described above, a cosine wave cos(2πft) is generally used as the carrier wave. As described above, the modulated in-phase signal has a waveform like the signal waveform 304 shown in FIG. 3C.

[0029] Meanwhile, the quadrature signal input from baseband signal processing unit 201 to quadrature signal processing unit 203 via path 209 is mixed with a signal obtained by shifting the carrier wave generated by carrier wave generation unit 401 in phase shift unit 403, and the mixed signal is modulated. The phase angle in phase shift unit 403 is typically ±90 degrees, and the phase-shifted signal becomes a sine wave sin(2πft). As described above, the modulated quadrature signal has a waveform like signal waveform 305 shown in FIG. 3C.

[0030] The carrier wave generating unit 401 arranged in the carrier wave generating unit 400 may generate a terahertz wave as a carrier wave. In other words, the frequency band of the carrier waves of the in-phase signal and the quadrature signal may be the frequency band of the terahertz wave. The carrier wave generating unit 401 may include an oscillation element such as a resonant tunneling diode (RTD) or a CMOS (Complementary Metal Oxide Semiconductor) inverter. The carrier wave is not limited to the terahertz wave band, and bands such as millimeter waves and microwaves may be used. Furthermore, the in-phase signal processing unit 202 and the quadrature signal processing unit 203 are also called mixers and may be composed of diodes, field effect transistors (FETs), etc. The phase shifting unit 403 may be composed of, for example, a line with a length of a quarter wavelength.

[0031] FIG. 5 is a diagram showing a modified example of the modulation section 210 shown in FIG. 4 . In the configuration shown in FIG. 5 , the carrier generation section 500 includes an in-phase carrier generation section 501 and a quadrature carrier generation section 503. As a result, the carrier generation section 500 is configured to independently generate carriers for the in-phase signal and the quadrature signal. In the in-phase signal processing section 202, the carrier generated by the in-phase carrier generation section 501 is mixed with the in-phase signal input via path 208 to generate a modulated in-phase signal (signal waveform 304). Similarly, in the quadrature signal processing section 203, the carrier generated by the quadrature carrier generation section 503 is mixed with the quadrature signal input via path 209 to generate a modulated quadrature signal (signal waveform 305). In the carrier generation section 500, the carrier generated by the in-phase carrier generation section 501 and the carrier generated by the quadrature carrier generation section 503 must be orthogonal.

[0032] The frequency bands of the carrier waves generated by the in-phase carrier generation unit 501 and the quadrature carrier generation unit 503 arranged in the carrier generation unit 500 may be the terahertz wave frequency band, similar to the carrier generation unit 401 arranged in the above-described carrier generation unit 400. The in-phase carrier generation unit 501 and the quadrature carrier generation unit 503 may include oscillation elements such as a resonant tunneling diode (RTD) or a CMOS (Complementary Metal Oxide Semiconductor) inverter. The carrier wave is not limited to the terahertz wave band, and bands such as millimeter waves and microwaves may also be used.

[0033] The modulation units 210 shown in Figures 4 and 5 may be connected in multiple stages. For example, a superheterodyne system in which two modulation units 210 are connected in two stages can be used. In the superheterodyne system, for example, the carrier frequency of the first stage, called the intermediate frequency, is generally set to the order of kHz or MHz, and the carrier frequency of the second stage is set to the order of GHz. Furthermore, by arranging an amplifier in each stage and amplifying the signal, communication can be stabilized.

[0034] Next, the configuration of the wireless communication unit 110 during reception will be described with reference to Fig. 6. The wireless communication unit 110 can include an antenna 601, an in-phase signal processing unit 602, an orthogonal signal processing unit 603, a baseband signal processing unit 604, a phase compensation unit 605, and a phase compensation control unit 606. The in-phase signal processing unit 602 and the orthogonal signal processing unit 603 form a demodulation unit 609. The antenna 601 may be an unbalanced antenna, for example, a monopole antenna.

[0035] An in-phase signal processing unit 602 and a quadrature signal processing unit 603 arranged in the demodulation unit 609 demodulate a data signal input from the antenna 601. The in-phase signal processing unit 602 is connected to the antenna 601 and a baseband signal processing unit 604. The in-phase signal processing unit 602 is also connected to a phase compensation control unit 606. The quadrature signal processing unit 603 is connected to the antenna 601 and a phase compensation unit 605. The phase compensation unit 605 is connected to the quadrature signal processing unit 603, the baseband signal processing unit 604, and the phase compensation control unit 606. Here, the path connecting the antenna 601 and the baseband signal processing unit 604 via the in-phase signal processing unit 602 is called a path 607. Similarly, the path connecting the antenna 601 and the baseband signal processing unit 604 via the quadrature signal processing unit 603 and the phase compensation unit 605 is called a path 608.

[0036] Next, the signal processing of the wireless communication unit 110 will be described using the signal waveforms generated in the in-phase signal processing unit 602, the quadrature signal processing unit 603, the phase compensation unit 605, and the baseband signal processing unit 604. The received signal waveforms at positions (i), (ii), and (iii) in Figure 6 correspond to Figures 7A to 7C, respectively.

[0037] During reception, digital data is received by the wireless communication unit 110 via wireless communication with an external device (e.g., a transmitting device), and the demodulated data is stored in the storage unit 108, for example, or transferred to the application unit 109. For example, a waveform identical to the signal waveform 306 of the composite signal shown in Fig. 3D, such as signal waveform 706 shown in Fig. 7D, is input from the antenna 601 to the wireless communication unit 110. In this case, it is sufficient that a positive logic, double-current signal sequence with negative amplitude -A being 0 and positive amplitude A being 1 becomes [10010011], and the signal waveform 301 shown in Fig. 3A can be restored.

[0038] The received signal received by antenna 601 from electromagnetic waves in space has signal waveform 701 shown in FIG. 7A. The received signal passes through position (i) shown in FIG. 6 and is sent to in-phase signal processing unit 602 and quadrature signal processing unit 603, respectively, for demodulation. In-phase signal processing unit 602 outputs an in-phase signal having signal waveform 702 shown in FIG. 7B, and the signal sequence of this signal waveform 702 is "1001." Quadrature signal processing unit 603 outputs a quadrature signal having signal waveform 703 shown in FIG. 7B, and the signal sequence of this signal waveform 703 is "1010." At position (iii) shown in FIG. 6, the in-phase signal (signal waveform 704) is

[1001] , the same as signal waveform 702 shown in FIG. 7B. Meanwhile, the phase of the quadrature signal is compensated in phase compensation unit 605. More specifically, phase compensation unit 605 inverts the phase of the input signal. As a result, the quadrature signal output from phase compensation unit 605 becomes signal waveform 705 shown in FIG. 7C , and the signal sequence of this signal waveform 705 is "0101." Baseband signal processing unit 604, which generates a baseband signal based on the signals input from in-phase signal processing unit 602 and quadrature signal processing unit 603, performs parallel-to-serial conversion on the in-phase signal "1001" and quadrature signal "0101." As a result, baseband signal processing unit 604 obtains the baseband signal [10010011]. This signal sequence is the same as signal waveform 301, and indicates that communication is successful between the transmitting device and the receiving device.

[0039] The wireless communication unit 105 of the communication device 101 functioning as a transmitter outputs a notification signal indicating phase information corresponding to the phase difference between the in-phase signal output via path 208 and the quadrature signal output via path 209 to the receiver. For example, a phase notification unit 205 arranged in the wireless communication unit 105 generates the notification signal. Meanwhile, in the wireless communication unit 110 of the communication device 106 functioning as a receiver, a phase compensation unit 605 compensates the phase of the quadrature signal in this embodiment based on the notification signal from among the data signals received by the antenna 601. In the communication device 106 functioning as a receiver, the notification signal is a signal indicating phase information corresponding to the phase difference between the in-phase signal demodulated by the in-phase signal processing unit 602 and the quadrature signal demodulated by the quadrature signal processing unit 603. The phase compensation unit 605 inverts the phase of the input signal based on a control signal supplied from the phase compensation control unit 606.

[0040] In this embodiment, the phase compensation unit 605 inverts the phase of the input signal, but this is not limited thereto. The phase may be advanced or delayed by an appropriate angle depending on the demodulation of various signals. Furthermore, for example, if a notification signal cannot be received, the phase compensation control unit 606 may not supply a control signal, and the phase compensation unit may not perform phase compensation. Furthermore, for example, if a notification signal cannot be received, the phase compensation control unit 606 may not supply a control signal, and the phase compensation unit may maintain the previous phase compensation state. In other words, the state according to the previously received notification signal (for example, whether the phase is inverted or not inverted) may be maintained.

[0041] The waveform of the notification signal is, for example, signal waveform 801 shown in FIG. 8A. The signal sequence of signal waveform 801 is [1000000010000000]. This functions as header 803, assuming the signal sequence [10010011] of the above-mentioned baseband signal as payload 802. In other words, this means that the notification signal is sent before or simultaneously with the data signal to be transmitted. However, this is not limited thereto. If the storage unit 108 is configured to buffer the received and demodulated baseband signal, it is also possible to transmit only the notification signal later within the buffer period. In this case, the phase notification unit 205 outputs the notification signal after a combined signal corresponding to the in-phase signal and the quadrature signal is transmitted to the receiving device.

[0042] In the wireless communication unit 105 of the communication device 101, the phase notification unit 205 connected to the in-phase signal processing unit 202 adds a signal sequence [10001000], which functions as a notification signal, to the header portion before the signal sequence

[1001] of the in-phase signal (in the above example). Because the phase notification unit 205 is not connected to the orthogonal signal processing unit 203, no signal "1" is added to the header portion of the signal sequence

[0101] of the orthogonal signal processed by the orthogonal signal processing unit 203. Therefore, in the combined signal combined by the balanced antenna 204, an analog signal corresponding to the signal sequence [1000000010000000] combined with the carrier wave is added as the header 803 before the payload 802.

[0043] In this embodiment, the phase notification unit 205 adds a signal sequence functioning as a notification signal to the header portion of the in-phase signal. However, this is not limited thereto. For example, a signal sequence [1000000010000000] may be added to the header portion of the signal supplied to the baseband signal processing unit 201 of the wireless communication unit 105. For example, the control unit 102 of the communication device 101 may function as a phase notification unit and add a signal sequence functioning as a notification signal to the header portion of the signal supplied to the baseband signal processing unit 201. Furthermore, for example, the baseband signal processing unit 201 may add a signal sequence functioning as a notification signal to the header portion of data stored in the storage unit 103 or data used in the application unit 104. In other words, the baseband signal processing unit 201 may function as a phase notification unit. In these cases, it can be said that the control unit 102 or the baseband signal processing unit 201 functioning as a phase notification unit add notification signals to the header portions of the in-phase signal and the quadrature signal. In this case, the signal sequence that functions as the notification signal is not limited to the above-mentioned signal sequence, and for example, a signal "1" may be added to the header portion of the signal sequence of the orthogonal signal.

[0044] In the wireless communication unit 110 of the communication device 106, the header 803 is processed in the wireless communication unit 110 in the same manner as the payload 802 (baseband signal). The in-phase signal processing unit 602 demodulates the signal input from the antenna 601 and outputs an in-phase signal with a signal waveform 804 shown in FIG. 8B. The signal sequence of this signal waveform 804 is [10001000]. This signal sequence functions as a notification unit 806 before a data unit 805, which is an in-phase signal of the baseband signal. The orthogonal signal processing unit 603 demodulates the signal input from the antenna 601 and outputs an orthogonal signal with a signal waveform 807 shown in FIG. 8B. The signal sequence of this signal waveform 807 is [00000000]. This signal sequence functions as an invalid unit 809 before a data unit 808, which is an orthogonal signal of the baseband signal. The phase compensation control section 606 generates a control signal using the signal sequence [10001000] from the notification section 806 as a trigger, and the phase compensation section 605 inverts the input signal in accordance with the control signal.

[0045] Here, the control signal generated by the phase compensation control unit 606 may be generated by the control unit 107 of the communication device 106. That is, the control unit 107 may function as the phase compensation control unit 606. In this case, taking into account the time required for demodulation processing, the header 803 (notification signal) may be transmitted from the transmitting device prior to the payload 802, and the notification signal may be received in advance. In this case, the phase notification unit 205 outputs the notification signal before a composite signal corresponding to the in-phase signal and the quadrature signal is transmitted to the receiving device. Furthermore, in this embodiment, the notification signal functions as a trigger (ON / OFF) for compensation in the phase compensation unit 605, but may also be a signal indicating a phase difference (angle information). Depending on the modulation / demodulation method, the notification signal may represent various information.

[0046] An example of the configuration for demodulation in the demodulator 609 is shown in FIG. 9 . This configuration is the same as the modulator 210 shown in FIG. 4 , except that low-pass filters 903 and 906 are added. Therefore, the in-phase signal processor 202 and the in-phase signal processor 602 may have similar functions and configurations. Furthermore, the quadrature signal processor 203 and the quadrature signal processor 603 may have similar functions and configurations. Furthermore, the carrier generator 400 and the carrier generator 900 may have similar functions and configurations. The low-pass filters 903 and 906 remove harmonic components from the signal obtained after mixing the carrier and the received signal, and extract the DC component. In other words, they function in the same way as the integration in the above-described equations (2) and (3).

[0047] In the configuration shown in FIG. 9 , the in-phase signal passing through path 607 is mixed with a carrier wave generated by carrier wave generation unit 901 in in-phase signal processing unit 602. By mixing a signal with the same frequency as the in-phase signal, the in-phase signal contains a DC component and a double harmonic component. The mixed in-phase signal is demodulated by passing the DC component through low-pass filter 903 to baseband signal processing unit 604. Similarly, the quadrature signal passing through path 608 is mixed with a signal obtained by shifting the phase of the carrier wave generated by carrier wave generation unit 901 in phase shift unit 904 in quadrature signal processing unit 603, and demodulated by passing through low-pass filter 906. As described above, the imparting angle in phase shift unit 904 is typically ±90 degrees. The phase-shifted signal becomes a sine wave sin(2πft). Similar to the phase shift unit 403 described above, phase shift unit 904 can be configured using, for example, a quarter-wave line.

[0048] FIG. 10 is a diagram showing a modified example of the demodulation unit 609 shown in FIG. 9 . In the configuration shown in FIG. 10 , the carrier generation unit 1000 includes an in-phase carrier generation unit 1001 and a quadrature carrier generation unit 1004. As a result, the carrier generation unit 1000 is configured to independently generate carriers for the in-phase signal and the quadrature signal. The remaining configuration may be the same as that of the demodulation unit 609 shown in FIG. 9 . As with the modulation unit 210 shown in FIG. 5 , the carrier generated by the in-phase carrier generation unit 1001 and the carrier generated by the quadrature carrier generation unit 1004 need to be orthogonal in this embodiment.

[0049] In the above description, a patch antenna is used as the balanced antenna 204 of the communication device 101, but this is not limiting. A dipole antenna, a slot antenna, a bowtie antenna, or the like may also be used as the balanced antenna 204. In addition, in the above description, a monopole antenna, which is an unbalanced antenna, is used as the antenna 601 of the communication device 106, but this is not limiting. The antenna 601 may be a balanced antenna, in which case the positive port of the balanced antenna may be directly connected to the in-phase signal processing unit 602 and the negative port of the balanced antenna may be directly connected to the quadrature signal processing unit 603.

[0050] Furthermore, the phase notification unit 205 of the communication device 101 may be connected to the quadrature signal processing unit 203. In this case, the phase compensation unit 605 may be arranged on the path 607 on which the in-phase signal processing unit 602 is arranged. The phase notification unit 205 only needs to be able to assign a notification signal to either the in-phase signal or the quadrature signal. Accordingly, the phase compensation unit 605 only needs to be arranged at least either between the in-phase signal processing unit 602 and the baseband signal processing unit 604 or between the quadrature signal processing unit 603 and the baseband signal processing unit 604. For example, the phase compensation unit 605 may be arranged both between the in-phase signal processing unit 602 and the baseband signal processing unit 604 and between the quadrature signal processing unit 603 and the baseband signal processing unit 604.

[0051] With these configurations, the effects of this embodiment can be obtained not only with QPSK as a modulation / demodulation method, but also with other PSK, such as 8PSK and QAM. When QAM is used, an amplitude compensator may be provided to compensate (adjust) the amplitude.

[0052] Each component included in the communication devices 101 and 106 may be realized by a CMOS integrated circuit (IC) using silicon or the like. Furthermore, for example, each component included in the communication device 101 may be realized by an IC using a compound semiconductor such as gallium arsenide. The communication device 101 may be configured by a combination of an IC using a semiconductor such as silicon and an IC using a compound semiconductor.

[0053] In the above-described embodiment, the communication device 101 is configured to output a notification signal via a balanced antenna 204 that emits a composite signal corresponding to an in-phase signal and a quadrature signal. Similarly, the communication device 106 is configured to receive a notification signal via an antenna 601 for receiving a data signal. However, the transmission and reception of the notification signal is not limited to this. Figures 11 and 12 show exemplary configurations in which an antenna 1101 is provided in the wireless communication unit 105, and an antenna 1201 and a phase compensation unit 1202 are provided in the wireless communication unit 110. Hereinafter, descriptions of configurations that may be similar to those described above will be omitted as appropriate, and different configurations will be mainly described.

[0054] In the configuration shown in this embodiment, consider a case where a notification signal is transmitted and received via a communication path independent of a data signal. First, the function and configuration of the wireless communication unit 105 during transmission will be described with reference to Fig. 11. As shown in Fig. 11, the wireless communication unit 105 includes an antenna 1101 connected to the phase notification unit 205, in addition to the balanced antenna 204. The antenna 1101 may be an unbalanced antenna, for example, a monopole antenna.

[0055] When transmitting a data signal, the phase notification unit 205 outputs a notification signal via the antenna 1101 when a baseband signal is supplied to the baseband signal processing unit 201. The notification signal may be, for example, equivalent to the signal waveform 801 shown in FIG. 8A . However, the notification signal does not need to be a double-stream signal sequence and may be transmitted using a wireless communication method different from that for the data signal as long as the wireless communication unit 110 (phase compensation control unit 606) can demodulate it. In other words, the frequency bands of the carrier waves of the in-phase signal and quadrature signal may be different from the frequency band of the notification signal. Similarly, on the receiving side, the frequency bands of the carrier waves of the data signal received by the antenna 601 may be different from the frequency band of the notification signal. Since the processing subsequent to signal transmission may be the same as in the above-described embodiment, a description thereof will be omitted. For example, the configuration of the modulation unit 210 may be the same as the configurations shown in FIGS. 4 and 5 .

[0056] Next, the function and configuration of the wireless communication unit 110 during reception will be described with reference to Fig. 12. As shown in Fig. 12, the wireless communication unit 110 includes an antenna 1201 connected to the phase compensation control unit 606, in addition to the antenna 601. The antenna 1201 may be an unbalanced antenna, for example, a monopole antenna.

[0057] The notification signal received by the antenna 1201 from electromagnetic waves in space is sent to the phase compensation control unit 606. The phase compensation control unit 606 generates a control signal based on the notification signal and controls either the phase compensation unit 605 or the phase compensation unit 1202 to invert the phase of the input signal. The notification signal includes information on which of the in-phase and quadrature signals to invert. The signal to be inverted may depend on the configuration of the wireless communication unit 105, such as the connection status between the in-phase signal processing unit 202 and the quadrature signal processing unit 203 and the positive port 206 and negative port 207 of the balanced antenna 204. Therefore, the notification signal may include configuration information (connection information) of the communication device 101 (wireless communication unit 105) rather than an instruction to invert the phase of the signal. If the notification signal is configuration information, the signal waveform of the signal output from the signal processing unit connected to the negative port 207 of the in-phase signal processing unit 202 and the quadrature signal processing unit 203 is inverted. The processing subsequent to receiving the signal may be the same as in the above-described embodiment, and therefore will not be described here. For example, the configuration of the demodulation unit 609 may be similar to the configurations shown in FIGS.

[0058] Here, if a wireless link can be maintained between the wireless communication unit 105 and the wireless communication unit 110 by wireless communication via the antenna 1101, there is no need to send a wireless signal again after sending the notification signal. Furthermore, if the storage unit 103 or the storage unit 108 can store a unique ID such as a MAC address, there is no need to determine a communication device with which a wireless link has been established and send a notification signal. In other words, if a link is established between the communication device 101 functioning as a transmitter and the communication device 106 functioning as a receiver, and the communication device 106 is stored in the communication history of the communication device, the communication device 101 does not need to send a notification signal to the communication device 106. In this case, the phase compensation unit 605 or the phase compensation unit 1202 of the communication device 106 may perform phase compensation based on the notification signal received from the communication device 101 stored in the communication history in accordance with the phase compensation control unit 606.

[0059] In each of the above-described embodiments, the carrier wave is generated within modulation section 210. In this case, as shown in Figures 13A to 13C, resonant tunneling diodes (RTDs) 215, 216 serving as carrier wave signal sources may be arranged near at least one of positive port 206 and negative port 207. Below, an embodiment in which carrier wave signal sources are arranged near positive port 206 and negative port 207 will be described, focusing on differences from the above, and explanations of configurations that may be similar will be omitted as appropriate.

[0060] 2, 4, and 5, in a configuration in which a carrier wave is generated within the modulator 210, a modulated signal is transmitted between the positive port 206 and the modulator 210 and between the negative port 207 and the modulator 210. During transmission, the modulated signal is attenuated. This signal attenuation increases with increasing frequency, and is particularly noticeable in the millimeter wave and terahertz wave bands.

[0061] Therefore, in this embodiment, RTDs 215 and 216 are arranged near the positive port 206 and the negative port 207 as carrier signal sources. This suppresses signal attenuation due to transmission between the positive port 206 and the modulation unit 210 and between the negative port 207 and the modulation unit 210. For example, if the positive port 206 and the negative port 207 are configured with vias, the RTDs 215 and 216 may be arranged directly below the vias, or the RTDs 215 and 216 may be connected to signal lines immediately adjacent to the vias. It can also be said that the RTD 215 is connected to a path 208 between the in-phase signal processing unit 202 and the positive port 206, and the RTD 216 is connected to a path 209 between the quadrature signal processing unit 203 and the negative port 207. 13A , the RTD 215 may be connected to a position of the path 208 between the in-phase signal processing unit 202 and the positive port 206 that is closer to the positive port 206 than the in-phase signal processing unit 202. For example, the ratio of the length of the path 208 from the in-phase signal processing unit 202 to the connection part of the RTD 215 to the length of the path 208 from the connection part of the RTD 215 to the positive port 206 may be 1:2 or more, 1:5 or more, or 1:10 or more. Similarly, the RTD 216 may be connected to a position of the path 209 between the quadrature signal processing unit 203 and the negative port 207 that is closer to the negative port 207 than the quadrature signal processing unit 203. For example, the ratio of the length of the path 209 from the quadrature signal processing unit 203 to the connection part of the RTD 216 to the length of the path 209 from the connection part of the RTD 216 to the negative port 207 may be 1:2 or more, 1:5 or more, or 1:10 or more.

[0062] Next, the principles of a signal source using a resonant tunneling diode are explained. Resonant tunneling diodes are composed of multiple different semiconductor materials, such as indium, gallium, phosphorus, and arsenic. Resonant tunneling diodes used as signal sources have a double-barrier resonant tunneling structure, which creates a negative resistance region in which current decreases with increasing applied voltage within a specific applied voltage range due to the tunneling structure. By connecting a resonator to a resonant tunneling diode having a negative resistance region and applying a voltage in the negative resistance region, the resistance component of the resonator is canceled by the negative resistance of the resonant tunneling diode, resulting in oscillation at the resonant frequency of the resonator. The resonator connected to the resonant diode may be a resonator consisting of an inductor and a capacitor, an antenna, or a stub. Resonant tunneling diodes are often used as signal sources in the terahertz wave band due to their good response, but they may also be used in other frequency bands, such as millimeter waves and microwave bands.

[0063] As described above, in this embodiment, RTDs 215 and 216 are arranged as signal sources near the positive port 206 and the negative port 207, respectively. However, the resonant frequency of the resonator (not shown) is set to be approximately equal to the resonant frequency of the carrier wave generated by the modulation unit 210. The RTDs 215 and 216 are also connected to the modulation unit 210. When the carrier wave generated by the modulation unit 210 is injected into the RTDs 215 and 216, the signal generated from the signal source using the RTDs 215 and 216 is synchronized with the carrier wave. By synchronizing with the carrier wave, in the case of transmission, the attenuated signal transmitted from the modulation unit 210 is amplified. In addition, in the case of reception, for example, a small signal received by an antenna can be amplified and transmitted to the demodulation unit. As a result, signal attenuation due to transmission between the positive port 206 and the modulation unit 210 and between the negative port 207 and the modulation unit 210 can be suppressed in both transmission and reception. Here, the RTD may be arranged at either the positive port 206 or the negative port 207, or may be arranged at the positive port 206 and the negative port 207, respectively, as shown in Figures 13A and 13B. When the RTDs 215 and 216 are arranged at the positive port 206 and the negative port 207, respectively, they may be arranged at different locations between the ports. Furthermore, when the RTDs 215 and 216 are arranged at the positive port 206 and the negative port 207, respectively, the RTDs 215 and 216 may have the same structure or different structures. Furthermore, the voltages applied to the RTDs 215 and 216 and the resonators connected thereto may have the same structure or different structures.

[0064] Next, a case where the above-described communication devices 101 and 106 are applied to a terahertz camera system (imaging system) will be described with reference to Fig. 14. The terahertz camera system 1300 includes a transmitter 1301 that emits terahertz waves TW and a detector 1302 that detects the terahertz waves TW. The terahertz camera system 1300 further includes a controller 1303 that controls the operation of the transmitter 1301 and the detector 1302 based on an external signal, and processes an image based on the detected terahertz waves or outputs the image to the outside. The above-described communication device 101 may be used as the transmitter 1301, and the above-described communication device 106 may be used as the detector 1302.

[0065] The terahertz waves TW emitted from the transmitter 1301 are reflected by the object 1305 and detected by the detector 1302. A camera system having such transmitter 1301 and detector 1302 may also be called an active camera system. Note that the above-described communication device 106 can also be used as the detector 1302 in a passive camera system that does not include the transmitter 1301 and detects the terahertz waves emitted by the object 1305.

[0066] Next, with reference to FIG. 15 , a case where the above-described communication devices 101 and 106 are applied to a communication system will be described. The communication system may be configured using a superheterodyne system or a direct conversion system, using a simple ASK modulation method or the like. A superheterodyne communication system includes, for example, an antenna 1400, an amplifier 1401, a mixer 1402, a filter 1403, a mixer 1404, a converter 1405, a digital baseband modulator / demodulator 1406, and local oscillators 1407 and 1408. In the case of a receiving device, a terahertz wave TW received via the antenna 1400 is converted into an intermediate frequency signal by the mixer 1402, then converted into a baseband signal by the mixer 1404, and the analog waveform is converted into a digital waveform by the converter 1405. The digital waveform is then demodulated at the baseband to obtain a communication signal. In the case of a transmitting device, a communication signal is modulated and then converted from a digital waveform to an analog waveform by converter 1405, and then frequency-converted via mixer 1404 and mixer 1402, and output as a terahertz wave from antenna 1400. A direct conversion communication system includes antenna 1400, amplifier 1411, mixer 1412, modulator / demodulator 1413, and local oscillator 1414. In the direct conversion system, during reception, mixer 1412 directly converts the received terahertz wave into a baseband signal, and during transmission, mixer 1412 converts the baseband signal to be transmitted into a terahertz band signal. The other configurations are the same as those of the superheterodyne system. The above-described configurations of communication devices 101 and 106 can function as a receiving device and a transmitting device in a communication system such as that shown in FIG. 15.

[0067] The technical ideas derived from this disclosure are not limited to the disclosed exemplary embodiments, but are intended to encompass various modifications to the exemplary embodiments, or the replacement of equivalent structures or functions, etc. The scope of the following claims should be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0068] This application claims priority based on Japanese Patent Application No. 2024-150228 filed on August 30, 2024, and Japanese Patent Application No. 2025-053752 filed on March 27, 2025, the entire contents of which are incorporated herein by reference.

Claims

1. A communications device comprising: a baseband signal processing unit; an in-phase signal processing unit and a quadrature signal processing unit that modulate a data signal input from the baseband signal processing unit; and a balanced antenna having a first port and a second port, wherein the communications device comprises: a first path that connects the baseband signal processing unit and the first port via the in-phase signal processing unit; and a second path that connects the baseband signal processing unit and the second port via the quadrature signal processing unit, the first port and the second port having opposite polarities; and a phase notification unit that generates a notification signal to output a notification signal indicating phase information corresponding to the phase difference between the in-phase signal output via the first path and the quadrature signal output via the second path.

2. The communication device according to claim 1, wherein the phase notification section adds the notification signal to a header portion of either the in-phase signal or the quadrature signal.

3. The communication device according to claim 1, wherein the phase notification section adds the notification signal to header portions of the in-phase signal and the quadrature signal.

4. The communication device according to claim 1, wherein the notification signal is output before or after a signal corresponding to the data signal is output.

5. A communication device according to any one of claims 1 to 4, wherein the notification signal is output via the balanced antenna.

6. A communication device according to any one of claims 1 to 4, further comprising an antenna separate from said balanced antenna for outputting said notification signal.

7. The communication device according to claim 6, wherein the frequency bands of the carrier waves of the in-phase signal and the quadrature signal are different from the frequency band of the notification signal.

8. A communication device according to any one of claims 1 to 7, characterized in that the frequency band of the carrier waves of the in-phase signal and the quadrature signal is the frequency band of terahertz waves.

9. A communication device according to any one of claims 1 to 8, characterized in that a resonant tunneling diode is connected to at least one of the first path between the in-phase signal processing unit and the first port and the second path between the quadrature signal processing unit and the second port.

10. The communication device according to claim 9, characterized in that when the resonant tunneling diode is connected to the first path between the in-phase signal processing unit and the first port, the resonant tunneling diode synchronizes with the in-phase signal processed by the in-phase signal processing unit, and when the resonant tunneling diode is connected to the second path between the quadrature signal processing unit and the second port, the resonant tunneling diode synchronizes with the quadrature signal processed by the in-phase signal processing unit.

11. A communication device comprising an antenna, an in-phase signal processing unit and a quadrature signal processing unit that demodulate a data signal input from the antenna, and a baseband signal processing unit that generates a baseband signal based on the signals input from the in-phase signal processing unit and the quadrature signal processing unit, characterized in that the communication device further comprises a phase compensation unit that receives a notification signal indicating phase information corresponding to the phase difference between an in-phase signal demodulated by the in-phase signal processing unit and a quadrature signal demodulated by the quadrature signal processing unit, of the data signal, and compensates for the phase of at least one of the in-phase signal and the quadrature signal based on the notification signal.

12. The communication device according to claim 11, wherein the phase compensation unit is arranged at least either between the in-phase signal processing unit and the baseband signal processing unit, or between the quadrature signal processing unit and the baseband signal processing unit.

13. The communication device according to claim 11 or 12, wherein the phase compensation section compensates for the phase of one of the in-phase signal and the quadrature signal.

14. The communication device according to any one of claims 11 to 13, wherein the phase compensation section inverts the phase of an input signal and outputs the inverted signal.

15. A communication device according to any one of claims 11 to 14, characterized in that, if the notification signal cannot be received, the phase compensation unit does not perform phase compensation.

16. A communication device according to any one of claims 11 to 15, characterized in that the notification signal is received via the antenna.

17. A communication device according to any one of claims 11 to 15, further comprising an antenna separate from the antenna for receiving the notification signal.

18. The communication device according to claim 17, wherein the frequency band of the carrier wave of the data signal and the frequency band of the notification signal are different from each other.

19. A communication device according to any one of claims 11 to 18, characterized in that the frequency band of the carrier wave of the data signal is the frequency band of terahertz waves.

20. A communication device according to any one of claims 11 to 19, characterized in that a resonant tunneling diode is connected at least either between the in-phase signal processing unit and the antenna or between the quadrature signal processing unit and the antenna.

21. The communication device according to claim 20, characterized in that, when the resonant tunneling diode is connected between the in-phase signal processing unit and the antenna, the resonant tunneling diode amplifies the signal received by the antenna and transmits it to the in-phase signal processing unit, and when the resonant tunneling diode is connected between the orthogonal signal processing unit and the antenna, the resonant tunneling diode amplifies the signal received by the antenna and transmits it to the in-phase signal processing unit.

22. A communication system comprising a transmitting device and a receiving device, wherein the transmitting device includes a communication device according to any one of claims 1 to 10, and the receiving device includes a communication device according to any one of claims 11 to 21.

23. The communication system described in claim 22, characterized in that the transmitting device and the receiving device each have a memory unit that stores a communication history, and when a link between the transmitting device and the receiving device is established and the receiving device is stored in the communication history of the transmitting device, the transmitting device does not transmit the notification signal to the receiving device, and the phase compensation unit of the receiving device compensates the phase based on the notification signal received from the transmitting device stored in the communication history.

24. An imaging system comprising a transmitter that emits electromagnetic waves and a detector that detects the electromagnetic waves reflected by a subject or the electromagnetic waves emitted from the subject, wherein the transmitter includes a communication device according to any one of claims 1 to 10, and the detector includes a communication device according to any one of claims 11 to 21.

Images