Communication devices, communication systems, and imaging systems

Abstract

This technology provides advantages for communications using high-frequency electromagnetic waves such as terahertz waves. [Solution] A communication device comprising a baseband signal processing unit, a common-mode 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 device comprises a first path connecting the baseband signal processing unit and the first port via the common-mode signal processing unit, and a second path connecting the baseband signal processing unit and the second port via the quadrature signal processing unit, the first port and the second port being opposite in polarity to each other, and further comprising a phase notification unit that generates a notification signal in order to output a notification signal indicating phase information corresponding to the phase difference between the common-mode signal output via the first path and the quadrature signal output via the second path.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 describes oscillating terahertz waves, but does not describe a configuration for use in communication.

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

Means for Solving the Problems

[0006] In view of the above problems, a communication device according to an embodiment of the present invention is a communication device comprising: a baseband signal processing unit; a common-mode signal processing unit and an orthogonal 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 comprises: a first path connecting the baseband signal processing unit and the first port via the common-mode signal processing unit; and a second path connecting the baseband signal processing unit and the second port via the orthogonal signal processing unit, wherein the first port and the second port have opposite polarities, and further comprises a phase notification unit that generates a notification signal in order to output a notification signal indicating phase information corresponding to the phase difference between a common-mode signal output via the first path and an orthogonal signal output via the second path. [Effects of the Invention]

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

[0008] [Figure 1] A diagram showing an example configuration of the communication device according to this embodiment. [Figure 2] Figure 1 shows an example of the configuration of the wireless communication section of the communication device. [Figure 3] Figure 1 shows an example of the transmission waveform of a communication device. [Figure 4] Figure 1 shows an example of the configuration of the modulation section of the communication device. [Figure 5] Figure 1 shows an example of the configuration of the modulation section of the communication device. [Figure 6] Figure 1 shows an example of the configuration of the wireless communication section of the communication device. [Figure 7] Figure 1 shows an example of a received waveform from a communication device. [Figure 8] Figure 1 shows an example of the waveform of a notification signal from a communication device. [Figure 9] Figure 1 shows an example of the configuration of the demodulation unit of the communication device. [Figure 10] Figure 1 shows an example of the configuration of the demodulation unit of the communication device. [Figure 11] Figure 1 shows an example of the configuration of the wireless communication section of the communication device. [Figure 12] Figure 1 shows an example of the configuration of the wireless communication section of the communication device. [Figure 13] Figure 1 shows an example of the configuration of the wireless communication section of the communication device. [Figure 14] Figure 1 shows an example of the configuration of an imaging system using a communication device. [Figure 15] Figure 1 shows an example of a communication system configuration using the communication device shown in Figure 1. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] A communication device according to an embodiment of the present disclosure will be described with reference to Figures 1(a), 1(b) to 13. The configuration of the functional blocks of the communication device described below is merely an example. Some (and possibly all) of the functional blocks described may be replaced by other functional blocks that perform similar functions, some functional blocks may be omitted, and further functional blocks may be added. In addition, one functional block shown in the following description may be divided into multiple functional blocks, or multiple functional blocks may be integrated into one functional block.

[0011] FIG. 1(a) is a functional block diagram showing a configuration example of the communication device 101 in the present embodiment. FIG. 1(b) is a functional block diagram showing a configuration example of the communication device 106 in the present 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 performs wireless communication with an external device using the data in the storage unit 103 and the data used by the application unit 104. The wireless communication unit 105 performs modulation processing to place digital data on an analog signal and transmits the modulated analog signal as an electromagnetic wave in space. For example, the wireless communication may be public wireless such as 4G, 5G, 6G, or wireless communication based on standard specifications such as WLAN, Bluetooth (registered trademark), and Zigbee. Also, the wireless communication may be unique wireless communication based on a wireless protocol that is not a standard specification. The communication device 101 may also be called a transmitting device.

[0012] The communication device 106 may include a control unit 107, a storage unit 108, an application unit 109, and a wireless communication unit 110. The control unit 107, the storage unit 108, and the application unit 109 may have functions similar to those of the control unit 102, the storage unit 103, and the application unit 104, respectively. For example, the control unit 107, the storage unit 108, and the application unit 109 may have configurations similar to those of the control unit 102, the storage unit 103, and the application unit 104, respectively. The wireless communication unit 110 receives an electromagnetic wave in space and performs demodulation processing to extract digital data from the analog signal of the electromagnetic wave. The communication device 106 may also be called a receiving device. The communication device 101 and the communication device 106 may constitute a communication system by performing transmission and reception.

[0013] Next, the configuration of the wireless communication unit 105 during transmission will be described with reference to FIGS. 2(a) to 2(c). FIG. 2(a) is a block diagram showing a configuration example of the wireless communication unit 105. The wireless communication unit 105 may include a baseband signal processing unit 201, a cosine signal processing unit 202, a sine signal processing unit 203, a balanced antenna 204, and a phase notification unit 205. The cosine signal processing unit 202 and the sine signal processing unit 203 constitute a modulation unit 210.

[0014] The balanced antenna 204 includes 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. 2(b), and the voltage distribution in the vertical direction of the patch antenna shown in FIG. 2(b) is shown in FIG. 2(c). 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 the center line 211 as the boundary. The balanced antenna 204 includes 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. Since the polarities of these voltages vary with time, the polarities of the above voltages and ports indicate the voltage relationship at a certain point for convenience. That is, 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.

[0015] Here, in terms of practical use and design, it is easier to use when the positive port 206 and the negative port 207 have opposite phases. However, it is not limited to this. Here, the fact that the positive port 206 and the negative port 207 have opposite phases not only indicates 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, for example, 178 degrees, 183 degrees, etc., within the range from 175 degrees to 185 degrees. Even in such cases, the effects of this embodiment can be obtained. Also, the fact that the positive port 206 and the negative port 207 have opposite phases means that, based on the baseband signal, the phases of the signals at the positive port 206 and the negative port 207 are in an inverse relationship.

[0016] The common-mode signal processing unit 202 and the quadrature signal processing unit 203, located in the modulation unit 210, modulate the data signal input from the baseband signal processing unit 201. The common-mode signal processing unit 202 is connected to the baseband signal processing unit 201 and the positive port 206 of the balanced antenna 204. The common-mode 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 common-mode 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 common-mode signal processing unit 202 is called 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 called path 209.

[0017] Next, the signal processing of the wireless communication unit 105 will be explained using the signal waveforms generated in the baseband signal processing unit 201, the common-mode signal processing unit 202, and the quadrature signal processing unit 203, respectively. The waveforms of the transmitted signals at positions (i) and (ii) shown in Figure 2(a) are shown in Figures 3(b) and 3(c), respectively.

[0018] During transmission, digital data from the storage 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 a signal waveform 301, for example, as shown in Figure 3(a). The signal waveform 301 may be a positive logic, double-current signal sequence with negative amplitude -A as 0 and positive amplitude A as 1, and in the example shown in Figure 3(a), it is [10010011]. Hereafter, the explanation will use the example of a positive logic, double-current system, but other systems such as negative logic or single-current systems may also be used. Furthermore, in the following explanation, Quadrature Phase Shift Keying (QPSK) will be used as an example of modulation / demodulation for digital communication. However, it is not limited to this, and other systems may be used.

[0019] In QPSK modulation and demodulation, the baseband signal is converted serial-to-parallel in 2-bit increments by the baseband signal processing unit 201. That is, [10010011] in the signal waveform 301 is converted to

[1001] and

[0101] , and further, in the NRZ method,

[1001] is assigned to the common-mode (I) component (common-mode signal) and

[0101] to the quadrature (Q) component (quadrature signal). Figure 3(b) shows the signal waveform 302 of the common-mode signal before modulation and the signal waveform 303 of the quadrature signal before modulation at position (i) shown in Figure 2(a).

[0020] The common-mode signal is sent to the common-mode signal processing unit 202 and modulated. If the digital signal is 1, the carrier phase is 0 degrees, and if the digital signal is 0, the carrier phase is 180 degrees. Then,

[1001] in the signal waveform 302 becomes an analog signal mixed with the carrier, as shown in the signal waveform 304 in Figure 3(c). Similarly, the quadrature signal is modulated in the quadrature signal processing unit 203 and becomes an analog signal with the signal waveform 305 as shown in Figure 3(c). Here, the carrier waves mixed with the common-mode signal and the quadrature signal are a cosine wave cos(2πft) and a sine wave sin(2πft), which are orthogonal to each other, as will be described later.

[0021] The modulated common-mode 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 via position (ii) shown in Figure 2(a), where they are combined and radiated. The quadrature signal fed to the negative port 207 is input to the negative voltage region 213 within the balanced antenna 204, causing the phase to be inverted in the positive voltage region 212. Therefore, the common-mode signal and the phase-inverted quadrature signal are combined in the balanced antenna 204. The combined signal becomes the signal waveform 306 shown in Figure 3(d). In other words, the combined signal radiated from the balanced antenna 204 has the same shape as the signal waveform 306 obtained by combining the common-mode signal (signal waveform 304), which is a mixture of common-mode carriers, and the phase-inverted signal of the quadrature signal (signal waveform 305), which is a mixture of quadrature carriers.

[0022] Generally, cosine waves cos(2πft) and sine waves sin(2πft) are used as the common-mode carrier and quadrature carrier, respectively, when mixed with common-mode and quadrature signals. f is the carrier frequency, and t is the time variable. Here, quadrature means that the integral of the product of the function f(t) and the function g(t) over the entire interval is zero, i.e., it satisfies equation 1 below.

[0023]

number

[0024] The cosine wave and sine wave described above satisfy equation (1). By mixing signals with such orthogonal waves and transmitting them, it becomes possible to extract the mixed signal at reception. For example, if the common-mode signal is +1 and the orthogonal signal is -1, the combined signal will be cos(2πft) - sin(2πft). In demodulation at the receiving end, to extract the common-mode signal, the combined signal is multiplied by the cosine wave cos(2πft) as shown in equation (2), and integrated over the entire interval. The carrier wave is a wave that repeats with period T, and the integral over the entire interval is equivalent to period T. As a result of the calculation in equation (2), +1 / 2, or half of the common-mode signal component, can be extracted as the common-mode signal.

[0025]

number

[0026]

number

[0027] An example configuration for transmission, i.e., modulation, in the modulation unit 210 is shown in Figures 4 and 5. In the configuration shown in Figure 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 generator 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 generator 401 and modulated. As described above, a cosine wave cos(2πft) is generally used as the carrier wave. The modulated in-phase signal has a waveform like the signal waveform 304 shown in Figure 3(c), as described above.

[0028] On the other hand, the orthogonal signal input from the baseband signal processing unit 201 to the orthogonal signal processing unit 203 via path 209 is mixed with the signal obtained by shifting the carrier wave generated by the carrier wave generation unit 401 in the phase shift unit 403, and modulated. The input angle in the phase shift unit 403 is typically ±90 degrees, and the phase-shifted signal becomes a sine wave sin(2πft). The modulated orthogonal signal has a waveform like the signal waveform 305 shown in Figure 3(c), as described above.

[0029] The carrier wave generator 401, located in the carrier wave generation unit 400, may generate a terahertz wave as the carrier wave. In other words, the frequency band of the carrier waves for the common-mode and quadrature signals may be the terahertz wave frequency band. The carrier wave generator 401 may include an oscillator 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; millimeter waves or microwave bands may also be used. The common-mode signal processing unit 202 and the quadrature signal processing unit 203 are also called mixers and may be composed of diodes or field effect transistors (FETs). The phase shift unit 403 may be composed of, for example, a transmission line with a length of one-quarter wavelength.

[0030] Figure 5 shows a modified example of the modulation unit 210 shown in Figure 4. In the configuration shown in Figure 5, the carrier wave generation unit 500 includes an in-phase carrier wave generation unit 501 and a quadrature carrier wave generation unit 503. Thus, the carrier wave generation unit 500 is configured to independently generate carrier waves for in-phase signals and quadrature signals. In the in-phase signal processing unit 202, the carrier wave generated by the in-phase carrier wave generation unit 501 and the in-phase signal input via path 208 are mixed to generate a modulated in-phase signal (signal waveform 304). Similarly, in the quadrature signal processing unit 203, the carrier wave generated by the quadrature carrier wave generation unit 503 and the quadrature signal input via path 209 are mixed to generate a modulated quadrature signal (signal waveform 305). In the carrier wave generation unit 500, the carrier wave generated by the in-phase carrier wave generation unit 501 and the carrier wave generated by the quadrature carrier wave generation unit 503 must be orthogonal.

[0031] The frequency bands of the carrier waves generated by the in-phase carrier wave generator 501 and the orthogonal carrier wave generator 503, respectively, arranged in the carrier wave generation unit 500, may be in the terahertz frequency band, similar to the carrier wave generator 401 arranged in the carrier wave generation unit 400 described above. The in-phase carrier wave generator 501 and the orthogonal carrier wave generator 503 may be equipped with oscillation elements such as resonant tunneling diodes (RTDs) or CMOS (Complementary Metal Oxide Semiconductor) inverters. The carrier wave is not limited to the terahertz band; it may also use bands such as millimeter waves or microwaves.

[0032] The modulation units 210 shown in Figures 4 and 5 may be connected in multiple stages. For example, a superheterodyne system can be used, which connects two modulation units 210 in stages. In a superheterodyne system, it is common to set the carrier frequency of the first stage, called the intermediate frequency, to the order of kHz or MHz, and the carrier frequency of the second stage to the order of GHz. Furthermore, by placing amplifiers in each stage and amplifying the signal, communication can be stabilized.

[0033] Next, the configuration of the wireless communication unit 110 during reception will be explained using Figure 6. The wireless communication unit 110 may include an antenna 601, a common-mode signal processing unit 602, a quadrature signal processing unit 603, a baseband signal processing unit 604, a phase compensation unit 605, and a phase compensation control unit 606. The common-mode signal processing unit 602 and the quadrature signal processing unit 603 constitute the demodulation unit 609. The antenna 601 may be an unbalanced antenna, for example, a monopole antenna.

[0034] The common-mode signal processing unit 602 and the quadrature signal processing unit 603, located in the demodulation unit 609, demodulate the data signal input from the antenna 601. The common-mode signal processing unit 602 is connected to the antenna 601 and the baseband signal processing unit 604. The common-mode signal processing unit 602 is also connected to the phase compensation control unit 606. The quadrature signal processing unit 603 is connected to the antenna 601 and the 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 common-mode signal processing unit 602 is called 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 path 608.

[0035] Next, the signal processing of the wireless communication unit 110 will be explained using the signal waveforms generated in the common-mode signal processing unit 602, the quadrature signal processing unit 603, the phase compensation unit 605, and the baseband signal processing unit 604, respectively. The received signal waveforms at positions (i), (ii), and (iii) in Figure 6 correspond to Figures 7(a) to 7(c), respectively.

[0036] During reception, the digital data received and demodulated by the wireless communication unit 110 via wireless communication with an external device (e.g., a transmitting device) is stored in, for example, the storage unit 108, or passed to the application unit 109. For example, the same waveform as the combined signal waveform 306 shown in Figure 3(d), as the signal waveform 706 shown in Figure 7(d), is input from the antenna 601 to the wireless communication unit 110. In this case, it is sufficient that the signal waveform 301 shown in Figure 3(a) can be reconstructed by a positive logic, double-current signal sequence [10010011], where negative amplitude -A is 0 and positive amplitude A is 1.

[0037] The received signal from the electromagnetic waves in space, as received by antenna 601, is the signal waveform 701 shown in Figure 7(a). The received signal passes through position (i) shown in Figure 6 and is sent to the common-mode signal processing unit 602 and the quadrature signal processing unit 603, respectively, for demodulation. The common-mode signal processing unit 602 outputs the common-mode signal of signal waveform 702 shown in Figure 7(b), and the signal sequence of this signal waveform 702 is "1001". The quadrature signal processing unit 603 outputs the quadrature signal of signal waveform 703 shown in Figure 7(b), and the signal sequence of this signal waveform 703 is "1010". At position (iii) shown in Figure 6, the common-mode signal (signal waveform 704) remains unchanged from the signal waveform 702 shown in Figure 7(b), and is "1001". On the other hand, the phase of the quadrature signal is compensated in the phase compensation unit 605. More specifically, the phase compensation unit 605 inverts the phase of the input signal. As a result, the orthogonal signal output from the phase compensation unit 605 becomes the signal waveform 705 shown in Figure 7(c), and the signal sequence of this signal waveform 705 is "0101". The baseband signal processing unit 604, which generates a baseband signal based on the signals input from the common-phase signal processing unit 602 and the orthogonal signal processing unit 603, performs a parallel-to-serial conversion of the common-phase signal "1001" and the orthogonal signal "0101". As a result, the baseband signal processing unit 604 obtains the baseband signal [10010011]. This signal sequence is the same as the signal waveform 301, indicating that communication is possible between the transmitting device and the receiving device.

[0038] The wireless communication unit 105 of the communication device 101, which functions as a transmitter, outputs a notification signal to the receiving device that indicates phase information corresponding to the phase difference between the common-mode signal output via path 208 and the orthogonal signal output via path 209. For example, a phase notification unit 205 located in the wireless communication unit 105 generates the notification signal. On the other hand, in the wireless communication unit 110 of the communication device 106, which functions as a receiving device, the phase compensation unit 605 compensates the phase of the orthogonal signal in this embodiment based on the notification signal among the data signals received by the antenna 601. In the communication device 106, which functions as a receiving device, the notification signal is a signal that indicates phase information corresponding to the phase difference between the common-mode signal demodulated by the common-mode signal processing unit 602 and the orthogonal signal demodulated by the orthogonal signal processing unit 603. The phase compensation unit 605 inverts the phase of the input signal based on the control signal supplied from the phase compensation control unit 606.

[0039] In this embodiment, the phase compensation unit 605 inverts the phase of the input signal, but is not limited to this; it may advance or delay the phase 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 does not supply a control signal, and the phase compensation unit does not have to perform phase compensation. Also, for example, if a notification signal cannot be received, the phase compensation control unit 606 does not supply a control signal, and the phase compensation unit maintains the previous phase compensation state. In other words, it may maintain a state that follows the previously received notification signal (for example, inverting the phase or not inverting the phase).

[0040] The waveform of the notification signal is, for example, the signal waveform 801 shown in Figure 8(a). The signal sequence of signal waveform 801 is [1000000010000000]. This functions as a header 803 when the signal sequence [10010011] of the baseband signal mentioned above is used as the payload 802. In other words, the notification signal is sent before or simultaneously with the data signal to be transmitted. However, this is not the only option; if the storage unit 108 can buffer the received and demodulated baseband signal, it is also possible to transmit only the notification signal later within the buffer period. In that case, the phase notification unit 205 will output the notification signal after the combined signal corresponding to the in-phase signal and the quadrature signal has been transmitted to the receiving device.

[0041] In the wireless communication unit 105 of the communication device 101, the phase notification unit 205, connected to the common-phase signal processing unit 202, adds a signal sequence [10001000] that functions as a notification signal to the header portion before the signal sequence

[1001] of the common-phase signal (in the example above). Since the phase notification unit 205 is not connected to the orthogonal signal processing unit 203, the signal "1" is not added to the header portion of the signal sequence

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

[0042] In this embodiment, the phase notification unit 205 adds a signal sequence that functions as a notification signal to the header portion of the in-phase signal. However, it is not limited to this, and for example, the 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 that functions as a notification signal to the header portion of the signal supplied to the baseband signal processing unit 201. Alternatively, for example, the baseband signal processing unit 201 may add a signal sequence that functions as a notification signal to the header portion of the signal for data 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 also be said that the control unit 102 or the baseband signal processing unit 201, which functions as a phase notification unit, adds a notification signal to the header portion of the in-phase signal and the orthogonal signal. Furthermore, in that case, the signal sequence that functions as a notification signal is not limited to the signal sequence described above; for example, a "1" signal may be added to the header portion of an orthogonal signal sequence.

[0043] 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 way as the payload 802 (baseband signal). The common-mode signal processing unit 602 demodulates the signal input from the antenna 601 and outputs the common-mode signal of the signal waveform 804 shown in Figure 8(b). The signal sequence of this signal waveform 804 is [10001000]. This signal sequence functions as a notification unit 806 before the data unit 805, which is the common-mode signal of the baseband signal. The orthogonal signal processing unit 603 demodulates the signal input from the antenna 601 and outputs the orthogonal signal of the signal waveform 807 shown in Figure 8(b). The signal sequence of this signal waveform 807 is [00000000]. This signal sequence functions as a nullable unit 809 before the data unit 808, which is the orthogonal signal of the baseband signal. The phase compensation control unit 606 generates a control signal triggered by the signal sequence [10001000] from the notification unit 806, and the phase compensation unit 605 inverts the input signal according to the control signal.

[0044] Here, the control signal generated by the phase compensation control unit 606 described above may be generated by the control unit 107 of the communication device 106. In other words, the control unit 107 may function as the phase compensation control unit 606. In that case, considering 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 that case, the phase notification unit 205 will output the notification signal before the combined signal corresponding to the in-phase signal and the orthogonal signal is transmitted to the receiving device. In this embodiment, the notification signal functions as a trigger (ON / OFF) for compensation in the phase compensation unit 605, but it may also be a signal indicating the phase difference (angle information). Depending on the modulation / demodulation method, the notification signal can represent various types of information.

[0045] Figure 9 shows an example configuration for demodulation in the demodulation unit 609. The modulation unit 210 shown in Figure 4 is further configured with low-pass filters 903 and 906. Therefore, the common-mode signal processing unit 202 and the common-mode signal processing unit 602 may have similar functions and configurations. Similarly, the quadrature signal processing unit 203 and the quadrature signal processing unit 603 may have similar functions and configurations. Furthermore, the carrier wave generation unit 400 and the carrier wave generation unit 900 may have similar functions and configurations. The low-pass filters 903 and 906 remove harmonic components from the signal after mixing the carrier wave and the received signal, extracting the DC component. In other words, they function similarly to the integrals in equations (2) and (3) described above.

[0046] In the configuration shown in Figure 9, the in-phase signal passing through path 607 is mixed with the carrier wave generated by the carrier wave generator 901 and the in-phase signal processing unit 602. By mixing signals of the same frequency as the in-phase signal, the in-phase signal comes to contain a DC component and a second harmonic component. The mixed in-phase signal is demodulated by passing the DC component through the low-pass filter 903 to the baseband signal processing unit 604. Similarly, the quadrature signal passing through path 608 is mixed with the signal obtained by shifting the phase of the carrier wave generated by the carrier wave generator 901 in the phase-shifting unit 904 and the quadrature signal processing unit 603, and demodulated by passing through the low-pass filter 906. The phase shifting angle in the phase-shifting unit 904 is generally ±90 degrees, as described above. The phase-shifted signal becomes a sine wave sin(2πft). The phase-shifting unit 904 can be configured using, for example, a quarter-wavelength transmission line, similar to the phase-shifting unit 403 described above.

[0047] Figure 10 shows a modified example of the demodulation unit 609 shown in Figure 9. In the configuration shown in Figure 10, the carrier wave generation unit 1000 includes an in-phase carrier wave generation unit 1001 and a quadrature carrier wave generation unit 1004. Thus, the carrier wave generation unit 1000 is configured to independently generate carrier waves for the in-phase signal and the quadrature signal. The other configurations may be the same as those of the demodulation unit 609 shown in Figure 9. Similar to the modulation unit 210 shown in Figure 5, the carrier wave generated by the in-phase carrier wave generation unit 1001 and the carrier wave generated by the quadrature carrier wave generation unit 1004 must be orthogonal in this embodiment.

[0048] As described above, a patch antenna is used as the balanced antenna 204 of the communication device 101, but it is not limited to this. A dipole antenna, slot antenna, bowtie antenna, etc., may also be used as the balanced antenna 204. Also, as described above, a monopole antenna, which is an unbalanced antenna, is used as the antenna 601 of the communication device 106, but it is not limited to this. Antenna 601 may also be a balanced antenna, in which case the positive port of the balanced antenna may be directly connected to the common-mode signal processing unit 602, and the negative port of the balanced antenna may be directly connected to the orthogonal signal processing unit 603.

[0049] Furthermore, the phase notification unit 205 of the communication device 101 may be connected to the orthogonal signal processing unit 203. In that case, the phase compensation unit 605 may be located in the path 607 where the common-phase signal processing unit 602 is located. The phase notification unit 205 only needs to be able to assign a notification signal to either the common-phase signal or the orthogonal signal. Accordingly, the phase compensation unit 605 only needs to be located between the common-phase signal processing unit 602 and the baseband signal processing unit 604, and between the orthogonal signal processing unit 603 and the baseband signal processing unit 604. For example, the phase compensation unit 605 may be located both between the common-phase signal processing unit 602 and the baseband signal processing unit 604, and between the orthogonal signal processing unit 603 and the baseband signal processing unit 604.

[0050] With these configurations, the effects of this embodiment can be obtained not only with QPSK as a modulation / demodulation method, but also with other PSKs, such as 8PSK and QAM. When using QAM, an amplitude compensation unit may be provided to compensate (adjust) the amplitude.

[0051] Each component of the communication devices 101 and 106 may be implemented using CMOS ICs (Integrated Circuits) made of silicon or the like. Alternatively, for example, each component of the communication device 101 may be implemented using ICs made of compound semiconductors such as gallium arsenide. The communication device 101 may be composed of a combination of ICs made of semiconductors such as silicon and ICs made of compound semiconductors.

[0052] In the above-described embodiment, the communication device 101 is shown to output a notification signal via a balanced antenna 204 that radiates a combined signal corresponding to the common-mode signal and the orthogonal signal. Similarly, the communication device 106 is shown to receive a notification signal via an antenna 601 for receiving data signals. However, the transmission and reception of notification signals are not limited to these. Figures 11 and 12 show an example configuration in which the wireless communication unit 105 is provided with an antenna 1101, and the wireless communication unit 110 is provided with an antenna 1201 and a phase compensation unit 1202. Hereafter, explanations of configurations that may be the same as described above will be omitted as appropriate, and the focus will be on different configurations.

[0053] In the configuration shown in this embodiment, let us consider the case where notification signals are transmitted and received via a communication path independent of the data signals. First, the function and configuration of the wireless communication unit 105 during transmission will be explained using Figure 11. As shown in Figure 11, the wireless communication unit 105 includes an antenna 1101 connected to the phase notification unit 205, separate from the balanced antenna 204. The antenna 1101 may be an unbalanced antenna, for example, a monopole antenna.

[0054] When transmitting a data signal, the phase notification unit 205 outputs a notification signal via the antenna 1101, triggered by the supply of a baseband signal to the baseband signal processing unit 201. The notification signal may be equivalent to, for example, the signal waveform 801 shown in Figure 8(a). However, the notification signal does not need to be a double-current signal sequence; it may be transmitted using a different wireless communication method than 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 common-mode and quadrature signals may be different from the frequency band of the notification signal. Similarly, on the receiving side, the frequency bands of the carrier wave of the data signal received by the antenna 601 may be different from the frequency band of the notification signal. The processing after transmitting the signal may be the same as in the embodiments described above, so the explanation is omitted. For example, the configuration of the modulation unit 210 may be the same as the configuration shown in Figures 4 and 5.

[0055] Next, the functions and configuration of the wireless communication unit 110 during reception will be explained using Figure 12. As shown in Figure 12, the wireless communication unit 110 includes an antenna 1201 connected to the phase compensation control unit 606, separate from the antenna 601. The antenna 1201 may be an unbalanced antenna, for example, a monopole antenna.

[0056] The notification signal received by antenna 1201 from electromagnetic waves in space is sent to phase compensation control unit 606. Based on the notification signal, the phase compensation control unit 606 generates a control 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 the signal whose phase is to be inverted, among the common-mode signal and quadrature signal. The signal to be inverted may depend on the configuration of the wireless communication unit 105, such as the connection status between the common-mode 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 not be an instruction to invert the phase of the signal, but may include configuration information (connection information) of the communication device 101 (wireless communication unit 105). 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 common-mode signal processing unit 202 and the quadrature signal processing unit 203 is inverted. The processing after receiving the signal may be the same as in the embodiment described above, so the explanation is omitted. For example, the configuration of the demodulation unit 609 may be similar to the configuration shown in Figures 9 and 10.

[0057] Here, if a wireless link is maintained between the wireless communication unit 105 and the wireless communication unit 110 via wireless communication through the antenna 1101, it is not necessary to send another wireless signal after sending a notification signal. Also, if the storage unit 103 or storage unit 108 can store a unique ID such as a MAC address, it is not necessary to determine which communication device has previously established a wireless link and send a notification signal. In other words, if a link is established between the communication device 101, which functions as a transmitter, and the communication device 106, which functions 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 that case, the phase compensation unit 605 or 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, according to the phase compensation control unit 606.

[0058] In each of the embodiments described above, the carrier wave is generated within the modulation unit 210. In this case, as shown in Figure 13, resonant tunneling diodes (RTDs) 215 and 216, which serve as carrier signal sources, may be arranged near at least one of the positive port 206 and the negative port 207. Hereinafter, embodiments in which the carrier signal sources are arranged near the positive port 206 and the negative port 207 will be described, focusing on the differences from those described above, and descriptions of configurations that may be similar will be omitted as appropriate.

[0059] As shown in Figures 2, 4, and 5, in a configuration where a carrier wave is generated within the modulation unit 210, the modulated signal is transmitted between the positive port 206 and the modulation unit 210, and between the negative port 207 and the modulation unit 210. While the signal is transmitted, this modulated signal is attenuated. This signal attenuation becomes larger in the higher frequency bands, and is particularly noticeable in the millimeter-wave and terahertz-wave bands.

[0060] Therefore, in this embodiment, RTDs 215 and 216 are arranged as carrier signal sources near the positive port 206 and the negative port 207. 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 as vias, RTDs 215 and 216 may be arranged directly below the vias, or RTDs 215 and 216 may be connected to the signal line closest to the vias. It can also be said that RTD 215 is connected to the path 208 between the common-mode signal processing unit 202 and the positive port 206, and RTD 216 is connected to the path 209 between the quadrature signal processing unit 203 and the negative port 207. As shown in Figure 13, RTD 215 may be connected to a position in the path 208 between the common-mode signal processing unit 202 and the positive port 206 that is closer to the positive port 206 than to the common-mode signal processing unit 202. For example, the ratio of the length of the path 208 from the common-mode signal processing unit 202 to the connection point of the RTD215 to the length of the path 208 from the connection point of the RTD215 to the positive port 206 may be 1:2 or greater, 1:5 or greater, or 1:10 or greater. Similarly, the RTD216 may be connected to a position in the path 209 between the orthogonal signal processing unit 203 and the negative port 207 that is closer to the negative port 207 than to the orthogonal signal processing unit 203. For example, the ratio of the length of the path 209 from the orthogonal signal processing unit 203 to the connection point of the RTD216 to the length of the path 209 from the connection point of the RTD216 to the negative port 207 may be 1:2 or greater, 1:5 or greater, or 1:10 or greater.

[0061] Next, the principle of a signal source using a resonant tunneling diode will be explained. A resonant tunneling diode is composed of several different semiconductor materials such as indium, gallium, phosphorus, and arsenic. A resonant tunneling diode used as a signal source has a double-barrier resonant tunnel structure, and due to the tunnel structure, it has a negative resistance region in which the current decreases with increasing applied voltage in a specific applied voltage range. By connecting a resonator to a resonant tunneling diode with a negative resistance region and applying a voltage in the negative resistance region, the resistance component of the resonator is canceled out by the negative resistance of the resonant tunneling diode, causing oscillation at the resonant frequency of the resonator. The resonator connected to the resonant diode may be composed of an inductor and a capacitor, an antenna, or a stub. Because resonant tunneling diodes have good responsiveness, they are often used as signal sources in the terahertz wave band, but they may also be used in other frequency bands, for example, in the millimeter wave or microwave band.

[0062] In this embodiment, as described above, RTDs 215 and 216 are placed as signal sources near the positive port 206 and negative port 207. The resonant frequency of the resonator (not shown) is set to be approximately the same as the resonant frequency of the carrier wave generated by the modulation unit 210. RTDs 215 and 216 are connected to the modulation unit 210, and the carrier wave generated by the modulation unit 210 is injected into RTDs 215 and 216, so that the signals generated from the signal sources using RTDs 215 and 216 are synchronized with the carrier wave. By synchronizing with the carrier wave, in the case of transmission, the signal transmitted from the modulation unit 210 and attenuated is amplified. Also, for example, in the case of reception, the small signal received by the 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 located in either the positive port 206 or the negative port 207, or it may be located in both the positive port 206 and the negative port 207, as shown in Figure 13. When RTDs 215 and 216 are located in the positive port 206 and the negative port 207, their locations on the ports may differ. Also, when RTDs 215 and 216 are located in the positive port 206 and the negative port 207, RTDs 215 and 216 may be RTDs of the same structure or RTDs of different structures. Furthermore, the voltage applied to RTDs 215 and 216 and the resonators connected to them may be the same configuration or different configurations.

[0063] Next, with reference to Figure 14, the case in which the above-described communication devices 101 and 106 are applied to a terahertz camera system (imaging system) will be explained. The terahertz camera system 1300 has a transmitter 1301 that emits terahertz waves TW and a detection unit 1302 that detects terahertz waves TW. Furthermore, the terahertz camera system 1300 has a control unit 1303 that controls the operation of the transmitter 1301 and the detection unit 1302 based on an external signal, processes an image based on the detected terahertz waves, or outputs it to the outside. The above-described communication device 101 may be used as the transmitter 1301, or the above-described communication device 106 may be used as the detection unit 1302.

[0064] The terahertz wave TW emitted from the transmitter 1301 is reflected by the subject 1305 and detected by the detection unit 1302. A camera system having such a transmitter 1301 and detection unit 1302 can also be called an active camera system. In addition, even in a passive camera system that does not have a transmitter 1301 and detects terahertz waves emitted by the subject 1305, the above-described communication device 106 can be used as the detection unit 1302.

[0065] Next, with reference to Figure 15, the case in which the above-described communication devices 101 and 106 are applied to a communication system will be explained. As a communication system, configurations such as a superheterodyne system or a direct conversion system are envisioned, using a simple ASK modulation scheme. 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, the terahertz wave TW received via the antenna 1400 is converted to an intermediate frequency signal by the mixer 1402, then converted to a baseband signal by the mixer 1404, and the analog waveform is converted to a digital waveform by the converter 1405. Then, the digital waveform is demodulated in the baseband to obtain a communication signal. In the case of a transmitting device, after the communication signal is modulated, it is converted from a digital waveform to an analog waveform by a converter 1405, then frequency-converted via mixers 1404 and 1402, and output as a terahertz wave from antenna 1400. The 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, the received terahertz wave is directly converted into a baseband signal by mixer 1412, and during transmission, the baseband signal to be transmitted is converted into a terahertz signal by mixer 1412. The other configurations are the same as those of the superheterodyne system. The above configurations of communication devices 101 and 106 can function as a receiving device and a transmitting device in a communication system as shown in Figure 15.

[0066] The disclosures herein include the following communication devices, communication systems, and imaging systems.

[0067] (Item 1) A communication device comprising a baseband signal processing unit, an in-mode signal processing unit and an orthogonal signal processing unit that modulate data signals input from the baseband signal processing unit, and a balanced antenna having a first port and a second port, The system includes a first path connecting the baseband signal processing unit and the first port via the in-phase signal processing unit, and a second path connecting 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. A communication device further comprising a phase notification unit that generates a notification signal in order to output a notification signal indicating phase information corresponding to the phase difference between a common-mode signal output via the first path and an orthogonal signal output via the second path.

[0068] (Item 2) The communication device according to item 1, characterized in that the phase notification unit adds the notification signal to the header portion of either the in-phase signal or the orthogonal signal.

[0069] (Item 3) The communication device according to item 1, characterized in that the phase notification unit adds the notification signal to the header portion of the in-phase signal and the orthogonal signal.

[0070] (Item 4) The communication device according to item 1, characterized in that the notification signal is output before or after the output of a signal corresponding to the data signal.

[0071] (Item 5) A communication device according to any one of items 1 to 4, characterized in that the notification signal is output via the balanced antenna.

[0072] (Item 6) The communication device according to any one of items 1 to 4, further comprising an antenna other than the balanced antenna for outputting the notification signal.

[0073] (Item 7) The communication device according to item 6, characterized in that the frequency bands of the carriers of the in-phase signal and the orthogonal signal and the frequency band of the notification signal are different from each other.

[0074] (Item 8) A communication device according to any one of items 1 to 7, characterized in that the frequency bands of the carrier waves of the in-phase signal and the quadrature signal are in the terahertz frequency band.

[0075] (Item 9) A communication device according to any one of items 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.

[0076] (Item 10) When the resonant tunneling diode is connected to the first path between the common-mode signal processing unit and the first port, the resonant tunneling diode synchronizes with the common-mode signal processed by the common-mode signal processing unit. The communication device according to item 9, characterized in that when the resonant tunnel diode is connected to the second path between the orthogonal signal processing unit and the second port, the resonant tunnel diode synchronizes with the orthogonal signal processed by the common-mode signal processing unit.

[0077] (Item 11) A communication device comprising: an antenna; a common-mode signal processing unit and a quadrature signal processing unit that demodulate data signals input from the antenna; and a baseband signal processing unit that generates a baseband signal based on signals input from the common-mode signal processing unit and the quadrature signal processing unit, A communication device further comprising a phase compensation unit that receives a notification signal indicating phase information corresponding to the phase difference between the in-phase signal demodulated by the in-phase signal processing unit and the quadrature signal demodulated by the quadrature signal processing unit from the data signal, and compensates the phase of at least one of the in-phase signal and the quadrature signal based on the notification signal.

[0078] (Item 12) The communication device according to item 11, characterized in that the phase compensation unit is located between the in-phase signal processing unit and the baseband signal processing unit, and between the quadrature signal processing unit and the baseband signal processing unit, at least one of the two.

[0079] (Item 13) The communication device according to item 11 or 12, characterized in that the phase compensation unit compensates for the phase of one of the in-phase signal and the orthogonal signal.

[0080] (Item 14) The communication device according to any one of items 11 to 13, characterized in that the phase compensation unit inverts the phase of the input signal and outputs it.

[0081] (Item 15) A communication device according to any one of items 11 to 14, characterized in that, if the notification signal cannot be received, the phase compensation unit does not perform phase compensation.

[0082] (Item 16) A communication device according to any one of items 11 to 15, characterized in that it receives the notification signal via the antenna.

[0083] (Item 17) A communication device according to any one of items 11 to 15, further comprising an antenna other than the antenna for receiving the notification signal.

[0084] (Item 18) The communication device according to item 17, characterized in that the frequency band of the carrier wave of the data signal and the frequency band of the notification signal are different from each other.

[0085] (Item 19) A communication device according to any one of items 11 to 18, characterized in that the frequency band of the carrier wave of the data signal is in the terahertz wave frequency band.

[0086] (Item 20) A communication device according to any one of items 11 to 19, characterized in that a resonant tunneling diode is connected between the in-phase signal processing unit and the antenna, and between the orthogonal signal processing unit and the antenna.

[0087] (Item 21) When the resonant tunneling diode is connected between the common-mode signal processing unit and the antenna, the resonant tunneling diode amplifies the signal received by the antenna and transmits it to the common-mode signal processing unit. The communication device according to item 20, characterized in that 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 common-mode signal processing unit.

[0088] (Item 22) A communication system comprising a transmitting device and a receiving device, The transmitting device includes a communication device described in any one of items 1 through 10. The receiving device is characterized by including a communication device described in any one of items 11 to 21.

[0089] (Item 23) The transmitting device and the receiving device each include a storage unit for storing communication history. When a link is established between the transmitting device and the receiving device, 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. The communication system according to item 22, characterized in that the phase compensation unit of the receiving device performs phase compensation based on the notification signal received from the transmitting device stored in the communication history.

[0090] (Item 24) An imaging system comprising a transmitter that emits electromagnetic waves, and a detection unit that detects the electromagnetic waves reflected by the subject or electromagnetic waves emitted from the subject, The transmitting unit includes a communication device described in any one of items 1 to 10. The imaging system is characterized in that the detection unit includes a communication device described in any one of items 11 to 21.

[0091] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0092] 101,106: Communication equipment; 201,604: Baseband signal processing unit; 202,602: Common-mode signal processing unit; 203,603: Quadrature signal processing unit; 204: Balanced antenna; 206: Positive port; 207: Negative port; 208,209: Path; 601: Antenna; 605: Phase compensation unit

Claims

1. A communication device comprising a baseband signal processing unit, an in-mode signal processing unit and an orthogonal signal processing unit that modulate data signals input from the baseband signal processing unit, and a balanced antenna having a first port and a second port, The system includes a first path connecting the baseband signal processing unit and the first port via the in-phase signal processing unit, and a second path connecting 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. A communication device further comprising a phase notification unit that generates a notification signal in order to output a notification signal indicating phase information corresponding to the phase difference between a common-mode signal output via the first path and an orthogonal signal output via the second path.

2. The communication device according to claim 1, characterized in that the phase notification unit adds the notification signal to the header portion of either the in-phase signal or the orthogonal signal.

3. The communication device according to claim 1, characterized in that the phase notification unit adds the notification signal to the header portion of the common-mode signal and the orthogonal signal.

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

5. The communication device according to claim 1, characterized in that the notification signal is output via the balanced antenna.

6. The communication device according to claim 1, further comprising an antenna other than the balanced antenna for outputting the notification signal.

7. The communication device according to claim 6, characterized in that the frequency bands of the carriers of the in-phase signal and the orthogonal signal and the frequency band of the notification signal are different from each other.

8. The communication device according to claim 1, characterized in that the frequency bands of the carrier waves of the in-phase signal and the orthogonal signal are in the terahertz wave frequency band.

9. The communication device according to claim 1, 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. When the resonant tunneling diode is connected to the first path between the common-mode signal processing unit and the first port, the resonant tunneling diode synchronizes with the common-mode signal processed by the common-mode signal processing unit. The communication device according to claim 9, characterized in that when the resonant tunnel diode is connected to the second path between the orthogonal signal processing unit and the second port, the resonant tunnel diode synchronizes with the orthogonal signal processed by the common-mode signal processing unit.

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

13. The communication device according to claim 11, characterized in that the phase compensation unit compensates for the phase of one of the in-phase signal and the orthogonal signal.

14. The communication device according to claim 11, characterized in that the phase compensation unit inverts the phase of the input signal and outputs it.

15. The communication device according to claim 11, characterized in that if the notification signal cannot be received, the phase compensation unit does not perform phase compensation.

16. The communication device according to claim 11, characterized in that it receives the notification signal via the antenna.

17. The communication device according to claim 11, further comprising an antenna other than the antenna for receiving the notification signal.

18. The communication device according to claim 17, characterized in that 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. The communication device according to claim 11, characterized in that the frequency band of the carrier wave of the data signal is in the terahertz wave frequency band.

20. The communication device according to claim 11, characterized in that a resonant tunneling diode is connected between the in-phase signal processing unit and the antenna, and between the orthogonal signal processing unit and the antenna, at least one of the two.

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

22. A communication system comprising a transmitting device and a receiving device, The transmitting device includes the communication device described in any one of claims 1 to 10. The communication system is characterized in that the receiving device includes the communication device described in any one of claims 11 to 21.

23. The transmitting device and the receiving device each include a storage unit for storing communication history. When a link is established between the transmitting device and the receiving device, 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. The communication system according to claim 22, characterized in that the phase compensation unit of the receiving device performs phase compensation 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 detection unit that detects the electromagnetic waves reflected by the subject or electromagnetic waves emitted from the subject, The transmitting unit includes the communication device described in any one of claims 1 to 10. The imaging system is characterized in that the detection unit includes the communication device described in any one of claims 11 to 21.

Images