Communication equipment and communication 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 or demodulate an input signal, a balanced antenna having a first port and a second port, and a phase compensation unit that outputs a signal with the phase of the input signal compensated, 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 having opposite polarities, and the phase compensation unit being located in the baseband signal processing unit, the first path, or the second path.

Description

Technical Field

[0004] ,

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[0001] The present invention relates to a communication device and a communication 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 waveband 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 for oscillating electromagnetic waves in the terahertz waveband.

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 a quadrature signal processing unit that modulate or demodulate an input signal; a balanced antenna having a first port and a second port; and a phase compensation unit that outputs a signal with the phase of the input signal compensated, 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 quadrature signal processing unit, wherein the first port and the second port have opposite polarities, and the phase compensation unit is arranged in the baseband signal processing unit, the first path, or 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 / demodulation section of a communication device. [Figure 5] Figure 1 shows an example of the configuration of the modulation / demodulation section of a communication device. [Figure 6] Figure 1 shows an example of a received waveform from a communication device. [Figure 7] Figure 1 shows an example of the configuration of the modulation / demodulation section of a communication device. [Figure 8] Figure 1 shows an example of the configuration of the modulation / demodulation section of a communication device. [Figure 9] Figure 1 shows an example of the configuration of the wireless communication section of the communication device and an example of a transmitted waveform. [Figure 10] Figure 1 shows an example of a received waveform from a communication device. [Figure 11]Figure 1 shows an example of the configuration of the wireless communication section of the communication device and an example of a transmitted waveform. [Figure 12] Figure 1 shows an example of a received waveform from a 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 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 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 with other functional blocks that perform similar functions, some functional blocks may be omitted, or 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] Figure 1 is a functional block diagram showing an example configuration of the communication device 101 in 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 of 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 transmits the data from the storage unit 103 and the data used by the application unit 104 to external devices. The wireless communication unit 105 performs modulation processing to superimpose digital data onto an analog signal and transmits the modulated analog signal as an electromagnetic wave into space. The wireless communication unit 105 also receives the electromagnetic wave in space and performs demodulation processing to extract digital data from the analog signal of the electromagnetic wave. For example, wireless communication may be public wireless networks such as 4G, 5G, and 6G, or standard wireless communication such as WLAN, Bluetooth®, and Zigbee. Alternatively, wireless communication may be a proprietary wireless communication based on a non-standard wireless protocol.

[0012] Next, the configuration of the wireless communication unit 105 described above will be explained using Figures 2(a) to 2(c). Figure 2(a) is a block diagram showing an example configuration of the wireless communication unit 105. The wireless communication unit 105 may include a baseband signal processing unit 201, a common-mode signal processing unit 202, a quadrature signal processing unit 203, a balanced antenna 204, and a phase compensation unit 205. The common-mode signal processing unit 202 and the quadrature signal processing unit 203 constitute the modulation / demodulation unit 210.

[0013] 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 positive and negative of these voltages vary with time, the positive and negative of the above voltages and ports are shown for 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.

[0014] Here, in terms of practical use and design, it is easier to use when the positive port 206 and the negative port 207 are in opposite phases. However, it is not limited to this. Here, the fact that the positive port 206 and the negative port 207 are in opposite phases not only means that the phase difference between the positive port 206 and the negative port 207 is exactly 180 degrees, but also includes cases where it is, for example, between 175 degrees and 185 degrees such as 178 degrees or 183 degrees. Even in such cases, the effects of the present embodiment can be obtained. Also, the fact that the positive port 206 and the negative port 207 are in opposite phases means that, based on the baseband signal, 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. Details will be described later.

[0015] The in-phase signal processing unit 202 and the quadrature signal processing unit 203 arranged in the demodulation and modulation unit 210 perform modulation or demodulation of the input signal. 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 quadrature signal processing unit 203 is connected to the phase compensation unit 205 and the negative port 207 of the balanced antenna 204. 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 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.

[0016] In the configuration shown in Fig. 2(a), the phase compensation unit 205 is arranged in path 209. More specifically, the phase compensation unit 205 is arranged between the baseband signal processing unit 201 and the quadrature signal processing unit 203. As will be described later, the phase compensation unit 205 outputs a signal with the phase of the input signal compensated.

[0017] Next, the signal processing of the wireless communication unit 105 will be described using the signal waveforms generated in each of the baseband signal processing unit 201, the in-phase signal processing unit 202, the quadrature signal processing unit 203, and the phase compensation unit 205. First, the processing of the wireless communication unit 105 when transmitting a signal will be described. The waveforms of the transmission signals at positions (i), (ii), and (iii) shown in Fig. 2(a) are shown in Figs. 3(b), 3(c), and 3(d), respectively.

[0018] Digital data from the memory unit 103 and digital data calculated by the application unit 104 are wirelessly transmitted from the wireless communication unit 105 to external devices of the communication device 101. This digital data is called a baseband signal and has a waveform such as the baseband signal 301 shown in Figure 3(a). The baseband signal 301 may be a signal sequence of positive logic, double-current, with negative amplitude -A set to 0 and positive amplitude A set to 1, and in the example shown in Figure 3(a), it is [10010011]. Hereafter, the explanation will use the example of positive logic, double-current, but other methods such as negative logic or single-current may also be used. In addition, 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 methods may be used.

[0019] In QPSK modulation and demodulation, the baseband signal processing unit 201 performs serial-to-parallel conversion of the input baseband signal 301 two bits at a time. That is, the baseband signal 301[10010011] is converted into

[1001] and

[0101] . Furthermore, in this 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 waveforms of the common-mode signal 302 and the quadrature signal 303 at position (i) in Figure 2(a).

[0020] At position (ii) shown in Figure 2(a), the common-mode signal 304 remains unchanged from the common-mode signal 302 in Figure 3(b), as shown in Figure 3(c), and is

[1001] . On the other hand, the orthogonal signal 305 changes from

[0101] to

[1010] as the phase of the signal is inverted in the phase compensation unit 205, as shown in Figure 3(c).

[0021] The common-mode signal 304 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, the rectangular signal

[1001] of the common-mode signal 304 is mixed with the carrier to become the analog common-mode signal 306, as shown in Figure 3(d). Similarly, the quadrature signal 305 is modulated by the quadrature signal processing unit 203 to become the analog quadrature signal 307, as shown in Figure 3(d). Here, the carriers mixed into the common-mode signal 306 and the quadrature signal 307, respectively, are a cosine wave cos(2πft) and a sine wave sin(2πft), which are orthogonal to each other, as will be described later.

[0022] The modulated common-mode signal 306 and quadrature signal 307 are sent to the positive port 206 and negative port 207 of the balanced antenna 204, which have opposite polarities, respectively, and are combined and radiated by the balanced antenna 204. The quadrature signal 307 fed to the negative port 207 is input to the negative voltage region 213 within the balanced antenna 204, so its phase is inverted in the positive voltage region 212. Therefore, the common-mode signal 306 and the phase-inverted quadrature signal 307 are combined in the balanced antenna 204. The waveform of the combined signal 308 is as shown in Figure 3(e).

[0023] Thus, when transmitting a signal, the phase of the in-phase signal 306 input to the positive port 206 via path 208 is relative to the phase of the baseband signal 301 input to the baseband signal processing unit 201, and the phase of the quadrature signal 307 input to the negative port 207 via path 208 is relative to the phase of the baseband signal 301, and these are in opposite phase relationships. When the quadrature signal 307 is combined with the in-phase signal 306 by the balanced antenna 204, the phases are inverted again. As a result, a combined signal 308 in which the phases of the in-phase signal 306 and the quadrature signal 307 are aligned is combined and radiated from the balanced antenna 204.

[0024] The combined signal 308 transmitted from the balanced antenna 204 has the same shape as the waveform obtained by mixing the common-mode signal 302 and the quadrature signal 303 with the common-mode carrier and quadrature carrier, respectively, and then combining the mixed common-mode signal and quadrature signal. Generally, the cosine wave cos(2πft) and the sine wave sin(2πft) are used as the common-mode carrier and quadrature carrier, respectively, which are mixed with the common-mode signal and quadrature signal. f is the frequency of the carrier wave, 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 0, that is, it satisfies equation 1 below.

[0025]

number

[0026] 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.

[0027]

number

[0028] Similarly, the inverted phase signal can be obtained by multiplying the composite signal by a sine wave sin(2πft) as shown in equation (3) and integrating over the entire interval, thereby extracting half of the inverted phase signal component, which is -1 / 2.

[0029]

number

[0030] Figure 4 shows an example configuration for transmission, i.e., modulation, in the modulation / demodulation unit 210. As shown in Figure 4, the modulation / demodulation 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 common-mode signal processing unit 202 processes the common-mode signal 304 input via the path 208 according to the carrier wave generated by the carrier wave generator 401. In other words, in the common-mode signal processing unit 202, the common-mode signal 304 is mixed with the carrier wave input from the carrier wave generator 401 and modulated. As described above, a cosine wave cos(2πft) is generally used as the carrier wave. The waveform of the modulated common-mode signal 306 is as shown in Figure 3(d), as described above.

[0031] The orthogonal signal processing unit 203 processes the orthogonal signal 305 input via path 209 according to the carrier wave generated by the carrier wave generation unit 401 and phase-shifted by the phase shift unit 403. In other words, in the in-phase signal processing unit 202, the in-phase signal 304 is mixed with the carrier wave input from the carrier wave generation unit 401 via the phase shift unit 403 and modulated. The phase shift in the phase shift unit 403 is typically ±90 degrees, and the carrier wave input to the orthogonal signal processing unit 203 becomes a sine wave sin(2πft). The waveform of the modulated orthogonal signal 307 is as shown in Figure 3(d), as described above.

[0032] The carrier wave generator 401, located in the carrier wave generation unit 400, may generate terahertz waves as the carrier wave. 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 band; millimeter waves or microwaves 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.

[0033] Figure 5 shows a modified example of the modulation / demodulation 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 the in-phase signal and the quadrature signal. In the in-phase signal processing unit 202, the carrier wave generated by the in-phase carrier wave generation unit 501 of the carrier wave generation unit 500 and the in-phase signal 304 input via path 208 are mixed to generate the in-phase signal 306 shown in Figure 3(d). Similarly, in the quadrature signal processing unit 203, the carrier wave generated by the quadrature carrier wave generation unit 503 of the carrier wave generation unit 500 and the quadrature signal 305 input via path 209 are mixed to generate the quadrature signal 307 shown in Figure 3(d). The carrier wave generated by the in-phase carrier wave generator 501 and the carrier wave generated by the orthogonal carrier wave generator 503 must be orthogonal.

[0034] The in-phase carrier generation unit 501 and the orthogonal carrier generation unit 503, arranged in the carrier wave generation unit 500, may generate terahertz waves as carrier waves, similar to the carrier wave generation unit 401 arranged in the carrier wave generation unit 400 described above. The in-phase carrier generation unit 501 and the orthogonal carrier generation unit 503 may be equipped with oscillation elements such as resonant tunneling diodes (RTDs) or CMOS inverters. The carrier wave is not limited to the terahertz wave band; it may also use bands such as millimeter waves or microwaves.

[0035] The modulation / demodulation unit 210 shown in Figures 4 and 5 may be connected in multiple stages. For example, a superheterodyne configuration can be used, where two modulation / demodulation units 210 are connected in stages. For instance, the carrier frequency of the first stage, called the intermediate frequency, can be on the order of kHz or MHz, and the carrier frequency of the second stage can be on the order of GHz. Furthermore, by placing amplifiers in each stage to amplify the signal, communication can be stabilized.

[0036] Next, the processing of the wireless communication unit 105 when receiving a signal will be described. The balanced antenna 204 receives electromagnetic waves from space. The waveform of this received signal 601 is, for example, the waveform shown in Figure 6(a), and is the same as the composite signal 308 shown in Figure 3(e). The waveform of the common-mode signal 602 output on the positive port 206 side (position (iii) in Figure 2(a)) is the waveform shown in Figure 6(b), and is the same as the waveform of the received signal 601 shown in Figure 6(a). On the other hand, the waveform of the orthogonal signal 603 output on the negative port 207 side (position (iii) in Figure 2(a)) is the waveform shown in Figure 6(b), and is a waveform that is the polarity inverted of the waveform of the received signal 601 shown in Figure 6(a). These common-mode signal 602 and orthogonal signal 603 are input to the common-mode signal processing unit 202 and the orthogonal signal processing unit 203, respectively.

[0037] Figure 7 shows an example configuration for the modulation / demodulation unit 210, i.e., for reception, i.e., demodulation. Compared to the modulation configuration shown in Figure 4, the demodulation configuration adds low-pass filters 703 and 706 to the common-mode signal processing unit 202 and the quadrature signal processing unit 203, respectively. In the common-mode signal processing unit 202 and the quadrature signal processing unit 203, the carrier wave is mixed with the common-mode signal 602 and the quadrature signal 603, and then the signal passes through the low-pass filters 703 and 706. The low-pass filters 703 and 706 remove the harmonic components of the signal after mixing the carrier wave and the received signal, and extract the DC component. That is, they function similarly to the integrals in equations (2) and (3).

[0038] The common-mode signal processing unit 202 processes the common-mode signal 602 input via path 208 according to the carrier wave generated by the carrier wave generation unit 401. In other words, in the common-mode signal processing unit 202, the common-mode signal 602 is mixed with the carrier wave input from the carrier wave generation unit 401. The common-mode signal 602 comes to contain a DC component and a second harmonic component as a result of mixing it with a signal of the same frequency as the common-mode signal. The mixed signal is demodulated by the low-pass filter 703, which allows only the DC component to pass through, and the waveform of the common-mode signal 602 becomes a waveform like the common-mode signal 604 shown in Figure 6(c). Similarly, the quadrature signal processing unit 203 processes the quadrature signal 603 input via path 209 according to the carrier wave generated by the carrier wave generation unit 401 and phase-shifted by the phase-shifting unit 403. In other words, in the orthogonal signal processing unit 203, the orthogonal signal 603 is mixed with the carrier wave input from the carrier wave generation unit 401 via the phase shift unit 403. The mixed signal is demodulated by the low-pass filter 706, which allows only the DC component to pass through, and the waveform of the orthogonal signal 603 becomes a waveform like the orthogonal signal 605 shown in Figure 6(c). As mentioned above, the phase shift in the phase shift unit 403 is typically ±90 degrees.

[0039] Figure 8 shows a modified example of the modulation / demodulation unit 210 shown in Figure 7. In the configuration shown in Figure 8, similar to the configuration shown in Figure 5 during modulation, the carrier wave generation unit 500 includes an in-phase carrier wave generation unit 501 and a quadrature carrier wave generation unit 503. As a result, the carrier wave generation unit 500 is configured to independently generate carrier waves for the in-phase signal and the quadrature signal. Also, similar to the configuration shown in Figure 7, low-pass filters 803 and 806 are added to the in-phase signal processing unit 202 and the quadrature signal processing unit 203, respectively. In the in-phase signal processing unit 202 and the quadrature signal processing unit 203, the carrier wave is mixed with the in-phase signal 602 and the quadrature signal 603, and then the signal passes through the low-pass filters 803 and 806.

[0040] In the configuration shown in Figure 8, the common-mode signal 602 is mixed with the carrier wave generated by the common-mode carrier wave generator 501 in the common-mode signal processing unit 202 and passes through the low-pass filter 803 to become the common-mode signal 604 shown in Figure 6(c). Similarly, the quadrature signal 603 is mixed with the carrier wave generated by the quadrature carrier wave generator 503 in the quadrature signal processing unit 203 and passes through the low-pass filter 806 to become the quadrature signal 605 shown in Figure 6(c). Similar to the modulation configuration shown in Figure 5, the carrier wave generated by the common-mode carrier wave generator 501 and the carrier wave generated by the quadrature carrier wave generator 503 must be orthogonal.

[0041] As shown in Figures 7 and 8, the quadrature signal 605 demodulated by the modulation / demodulation unit 210 is further phase-inverted by the phase compensation unit 205. Therefore, at position (i) in Figure 2(a), the waveform of the quadrature signal 607 becomes the waveform shown in Figure 6(d). The common-mode signal 606 at position (i) in Figure 2(a) has the same shape as the common-mode signal 604 at position (ii) in Figure 2(a). Next, the common-mode signal 606 and the quadrature signal 607 are converted to parallel-serial in the baseband signal processing unit 201 to obtain the baseband signal 608. The baseband signal 608 is the same signal sequence as the baseband signal 301 described above, indicating that communication is possible between the transmitting device and the receiving device.

[0042] Thus, when receiving a signal, the in-phase signal 602 input from the positive port 206 to the path 208 and the orthogonal signal 603 input from the negative port 207 to the path 209 are in opposite phase with respect to the phase of the baseband signal 608 output from the baseband signal processing unit 201 after demodulation. However, the phase is compensated (inverted) by the phase compensation unit 205, allowing the wireless communication unit 105 to demodulate the baseband signal 608 from the received signal 601.

[0043] Up to this point, it has been explained that a patch antenna is used as the balanced antenna 204, but the balanced antenna 204 is not limited to a patch antenna. A dipole antenna, slot antenna, bowtie antenna, etc., may also be used as the balanced antenna 204. Furthermore, the phase compensation unit 205 is not limited to being located in the path 209.

[0044] In this embodiment, the phase compensation unit 205 is located in path 209. However, it is not limited to this, and the phase compensation unit 205 may be located in path 208, more specifically, between the baseband signal processing unit 201 and the in-phase signal processing unit 202. The phase compensation unit 205 only needs to be capable of compensating (inverting) the phase of either the signal passing through path 208 or the signal passing through path 209.

[0045] Furthermore, although QPSK was used as an example of the modulation / demodulation method in this explanation, the effects of this embodiment can also be obtained with other PSKs, such as 8PSK or QAM. When using QAM, an amplitude compensation unit may be provided to compensate (adjust) the amplitude of the signal. The amplitude compensation unit may be provided in both path 208 and path 209.

[0046] Each component of the communication device 101 may be realized by a CMOS IC (Integrated Circuit) made of silicon or the like. Alternatively, each component of the communication device 101 may be realized by an IC made of a compound semiconductor 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.

[0047] Furthermore, a reverse current prevention unit may be provided between the common-mode signal processing unit 202 and the positive port 206 of the balanced antenna 204 to prevent signals passing through path 209 from being input to the common-mode signal processing unit 202. Similarly, a reverse current prevention unit may be provided between the quadrature signal processing unit 203 and the negative port 207 of the balanced antenna 204 to prevent signals passing through path 208 from being input to the quadrature signal processing unit 203. The reverse current prevention unit can be implemented by a circulator, a rat race, or the like.

[0048] As described above, a phase compensation unit 205 is placed in one of the paths 208 and 209 from the baseband signal processing unit 201 to the positive port 206 and negative port 207 of the balanced antenna 204 to compensate for the phase of the signal. This enables communication using the positive port 206 and negative port 207 of the balanced antenna 204.

[0049] In the above-described embodiment, a phase compensation unit 205 was placed between the baseband signal processing unit 201 and the quadrature signal processing unit 203 (or common-mode signal processing unit 202). However, the embodiment is not limited to this, and as shown in Figure 9(a), the phase compensation unit 205 may be provided inside the baseband signal processing unit 201. The following description will focus on the differences from the above, and explanations of configurations that may be similar will be omitted as appropriate.

[0050] In the configuration shown in Figure 9(a), consider the case where a baseband signal 901[10010011], which is the same sequence of "0"s and "1"s as the baseband signal 301 described above, is transmitted, as shown in Figure 9(b). The phase compensation unit 205 located in the baseband signal processing unit 201 inverts the even bits of data in the baseband signal 901. The inverted signal 902 is [11000110] as shown in Figure 9(b). This inverted signal 902[11000110] is converted from serial to parallel in the baseband signal processing unit 201 and assigned to the in-phase (I) component (in-phase signal) and the quadrature (Q) component (quadrature signal), and sent to paths 208 and 209, respectively. The waveforms of the in-phase signal 903 and the quadrature signal 904 at position (i) in Figure 9(a) are the waveforms shown in Figure 9(c), and are the same as the waveforms of the in-phase signal 304 and the quadrature signal 305 described above. Next, the in-phase signal 903 and the quadrature signal 904 are modulated in the in-phase signal processing unit 202 and the quadrature signal processing unit 203. The processing in the in-phase signal processing unit 202 and the quadrature signal processing unit 203 may be the same as described above, so the explanation is omitted. The waveforms of the modulated in-phase signal 905 and quadrature signal 906 at position (ii) in Figure 9(a) are the waveforms shown in Figure 9(d), respectively, and are the same as the waveforms of the in-phase signal 306 and quadrature signal 307 described above. The waveform of the combined signal 907 transmitted from the balanced antenna 204 is the waveform shown in Figure 9(e), and the same signal as the combined signal 308 described above is transmitted. Furthermore, the configuration of the modulation / demodulation unit 210 may be the same as in Figures 4 and 5 described above, so the explanation is omitted.

[0051] Next, the processing of the wireless communication unit 105 when receiving a signal in the configuration shown in Figure 9(a) will be explained. The configuration of the modulation / demodulation unit 210 may be the same as that shown in Figures 7 and 8 above, so its explanation will be omitted.

[0052] The balanced antenna 204 of the communication device 101 receives electromagnetic waves from space. The waveform of the received signal 1001 is the waveform shown in Figure 10(a), and is the same waveform as the composite signal 907. The waveforms of the common-mode signal 1002 and the quadrature signal 1003 at position (ii) in Figure 9(a) are the waveforms shown in Figure 10(b), and are the same as the waveforms of the common-mode signal 602 and the quadrature signal 603 described above. The common-mode signal 1002 is the signal that passes through path 208, and the quadrature signal 1003 is the signal that passes through path 209.

[0053] The common-mode signal 1002 and the quadrature signal 1003 are mixed with the carrier wave in the common-mode signal processing unit 202 and the quadrature signal processing unit 203, and demodulated by passing through the low-pass filters 703, 706, 803, and 806. The processing in the common-mode signal processing unit 202 and the quadrature signal processing unit 203 is the same as described above. As a result, the common-mode signal 1004 and the quadrature signal 1005 are obtained at position (i) in Figure 9(a).

[0054] Next, the phase compensation unit 205 located in the baseband signal processing unit 201 inverts the phase of the orthogonal signal 1005 to obtain the orthogonal signal 1007 shown in Figure 10(d). The in-phase signal 1006 shown in Figure 10(d) is the same as the in-phase signal 1004. The baseband signal processing unit 201 performs a parallel-to-serial conversion on the in-phase signal 1006 and the orthogonal signal 1007. This yields the baseband signal 1008, [10010011]. The baseband signal 1008 is the same signal sequence as the baseband signal 901 described above, indicating that communication is possible between the transmitting and receiving devices.

[0055] In this embodiment, the phase compensation unit 205 was described as compensating (inverting) the phase of orthogonal signals. That is, the phase compensation unit 205 was described as inverting the phase of the signal output from the baseband signal processing unit 201 to path 209 and the signal input from path 209 to the baseband signal processing unit 201. However, it is not limited to this, and the phase compensation unit 205 may also compensate (invert) the phase of common-mode signals. That is, the phase compensation unit 205 may also invert the phase of the signal output from the baseband signal processing unit 201 to path 208 and the signal input from path 208 to the baseband signal processing unit 201. The phase compensation unit 205 only needs to be able to compensate (invert) the phase of either the signal passing through path 208 or the signal passing through path 209.

[0056] In each of the embodiments described above, the phase compensation unit 205 compensates for the phase of the common-mode or quadrature signal before modulation or after demodulation. However, the timing of phase compensation is not limited to this. The phase compensation unit 205 may compensate for the phase of the common-mode or quadrature signal after modulation or before demodulation. In the configuration shown in Figure 11(a), the phase compensation unit 205 is located between the quadrature signal processing unit 203 on the path 209 and the negative port 207 of the balanced antenna 204. The following description will focus on the differences from those described above, and descriptions of configurations that may be similar will be omitted as appropriate.

[0057] In the configuration shown in Figure 11(a), we consider the case where the baseband signal 1101, [10010011], shown in Figure 11(b), which is a sequence of "0"s and "1"s, the same as the baseband signal 301 described above, is transmitted. The waveforms of the transmitted signals at positions (i), (ii), and (iii) shown in Figure 11(a) are shown in Figures 11(c), 11(d), and 11(e), respectively.

[0058] The baseband signal 1101 is converted from serial to parallel in the baseband signal processing unit 201 and assigned to a common-mode (I) component (common-mode signal) and a quadrature (Q) component (quadrature signal), which are sent to paths 208 and 209, respectively. The waveforms of the common-mode signal 1102 and quadrature signal 1103 at position (i) in Figure 11(a) are the waveforms shown in Figure 9(c). The common-mode signal 1102 and quadrature signal 1103 are modulated in the modulation / demodulation unit 210 to become the common-mode signal 1104 and quadrature signal 1105 as shown in Figure 11(d). The configuration and processing of the common-mode signal processing unit 202 and the quadrature signal processing unit 203 (modulation / demodulation unit 210) may be the same as described above, so a description is omitted.

[0059] The orthogonal signal 1105 is further phase-compensated by the phase compensation unit 205. Here, we describe the case where the positive port 206 and negative port 207 of the balanced antenna 204 have a phase difference of 180 degrees, as shown in Figures 2(b) and 2(c). In this case, the phase compensation is inverted by 180 degrees, and the orthogonal signal 1107, as shown in Figure 11(e), is obtained from the orthogonal signal 1105. The waveform of the common-mode signal 1106 at position (iii) in Figure 11(a) is the same waveform as the common-mode signal 1104 at position (ii). The common-mode signal 1106 and the orthogonal signal 1107 are combined in the balanced antenna 204 and transmitted from the balanced antenna 204 as the combined signal 1108 shown in Figure 11(f). The waveform of the combined signal 1108 is the same waveform as the combined signals 308 and 907 described above.

[0060] Next, the processing of the wireless communication unit 105 when receiving a signal in the configuration shown in Figure 11(a) will be described. The received signal waveform is shown in Figure 12. The waveforms of the received signals in (i), (ii), and (iii) shown in Figure 11(a) are shown in Figures 12(d), 12(c), and 12(b), respectively.

[0061] The balanced antenna 204 of the communication device 101 receives electromagnetic waves from space. The waveform of the received signal 1201 is the waveform shown in Figure 12(a), and is the same waveform as the composite signal 1108. The waveforms of the common-mode signal 1202 and the orthogonal signal 1203 at position (iii) in Figure 11(a) are the waveforms shown in Figure 12(b), and are the same waveforms as the common-mode signals 602 and 100 and the orthogonal signals 603 and 1003 described above. The common-mode signal 1202 is the signal that passes through path 208, and the orthogonal signal 1203 is the signal that passes through path 209.

[0062] Next, the orthogonal signal 1203 passing through path 209 is phase-compensated by the phase compensation unit 205, in this case by 180 degrees, i.e., inverted. As a result, the orthogonal signal 1205 shown in Figure 12(c) is obtained. The waveform of the common-mode signal 1204 passing through path 208 is the same as the waveform of the common-mode signal 1202 at position (iii) at position (ii). The common-mode signal 1204 and the orthogonal signal 1205 are demodulated in the common-mode signal processing unit 202 and the orthogonal signal processing unit 203 (modulation / demodulation unit 210), respectively, to obtain the common-mode signal 1206 and the orthogonal signal 1207. The configuration and processing of the common-mode signal processing unit 202 and the orthogonal signal processing unit 203 (modulation / demodulation unit 210) may be the same as described above, so a description is omitted.

[0063] The common-mode signal 1206 and the orthogonal signal 1207 are converted to parallel-serial format in the baseband signal processing unit 201 to obtain the baseband signal 1208 [10010011]. The baseband signal 1208 is the same signal sequence as the baseband signal 1101 described above, indicating that communication is possible between the transmitting and receiving devices.

[0064] Phase compensation in the phase compensation unit 205 can be implemented, for example, in a high-frequency signal transmission line. When the phase of the signal is inverted as described above, the phase compensation unit 205 can be implemented by using a transmission line with a length that is an odd multiple of approximately half a wavelength of the carrier wave generated by the carrier wave generation units 400 and 500. In practice, using the shortest transmission line, approximately half a wavelength, reduces the wiring area. For example, in the case of a carrier wave with a frequency of 300 GHz, one wavelength is approximately 1 mm. When mounting such a transmission line on a dielectric substrate, the wavelength should be chosen considering the dielectric constant of the dielectric and the transmission line structure. Also, for example, if the phase difference between the positive port 206 and the negative port 207 of the balanced antenna 204 is not 180 degrees (not in opposite phase), for example, if the phase difference between the positive port 206 and the negative port 207 is 150 degrees, the transmission line length should be set according to the phase difference to be compensated. This allows for compensation of the signal phase.

[0065] In the configuration shown in Figure 11(a), the phase compensation unit 205 is located between the orthogonal signal processing unit 203 on path 209 and the negative port 207 of the balanced antenna 204. However, it is not limited to this configuration, and the phase compensation unit 205 may also be located between the common-mode signal processing unit 202 on path 208 and the positive port 206 of the balanced antenna 204. The phase compensation unit 205 only needs to be capable of compensating (inverting) the phase of either the signal passing through path 208 or the signal passing through path 209.

[0066] Furthermore, as described above, the modulation / demodulation units 210 may be connected in multiple stages. For example, in the case of a superheterodyne system in which two modulation / demodulation units 210 are connected in stages, a phase compensation unit 205 may be placed between the two modulation / demodulation units 210 to compensate for the phase of the signal in the intermediate frequency band.

[0067] In each of the embodiments described above, the carrier wave is generated within the modulation / demodulation unit 210. In this case, as shown in Figure 13, resonant tunneling diodes (RTDs) 214 and 215, 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.

[0068] As shown in Figures 2, 9, and 11, in a configuration where a carrier wave is generated within the modulation / demodulation unit 210, a modulated signal is transmitted between the positive port 206 and the modulation / demodulation unit 210, and between the negative port 207 and the modulation / demodulation unit 210. While the signal is transmitted, this modulated signal is attenuated. This signal attenuation becomes larger in the higher frequency band, and is particularly noticeable in the millimeter-wave and terahertz-wave bands.

[0069] Therefore, in this embodiment, RTDs 214 and 215 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 / demodulation unit 210, and between the negative port 207 and the modulation / demodulation unit 210. For example, if the positive port 206 and the negative port 207 are configured as vias, RTDs 214 and 215 may be arranged directly below the vias, or RTDs 214 and 215 may be connected to the signal line closest to the vias. It can also be said that RTD 214 is connected to the path 208 between the common-mode signal processing unit 202 and the positive port 206, and RTD 215 is connected to the path 209 between the quadrature signal processing unit 203 and the negative port 207. As shown in Figure 13, RTD214 may be connected to a position closer to the positive port 206 than to the common-mode signal processing unit 202 within the path 208 between the common-mode signal processing unit 202 and the positive port 206. For example, the ratio of the length of path 208 from the common-mode signal processing unit 202 to the connection point of RTD214 to the length of path 208 from the connection point of RTD214 to the positive port 206 may be 1:2 or greater, 1:5 or greater, or 1:10 or greater. Similarly, RTD215 may be connected to a position closer to the negative port 207 than to the orthogonal signal processing unit 203 within the path 209 between the orthogonal signal processing unit 203 and the negative port 207. For example, the ratio of the length of path 209 from the orthogonal signal processing unit 203 to the connection point of RTD215 to the length of path 209 from the connection point of RTD215 to the negative port 207 may be 1:2 or greater, 1:5 or greater, or 1:10 or greater.

[0070] 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.

[0071] In this embodiment, as described above, RTDs 214 and 215 are placed near the positive port 206 and negative port 207 as signal sources. 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 / demodulation unit 210. RTDs 214 and 215 are connected to the modulation / demodulation unit 210, and the carrier wave generated by the modulation / demodulation unit 210 is injected into RTDs 214 and 215, so that the signals generated from the signal sources using RTDs 214 and 215 are synchronized with the carrier wave. By synchronizing with the carrier wave, in the case of transmission, the signal transmitted from the modulation / demodulation unit 210 and attenuated is amplified, and in the case of reception, the small signal received by the antenna is amplified and transmitted to the modulation / demodulation unit 210. As a result, signal attenuation due to transmission between the positive port 206 and the modulation / demodulation unit 210, and between the negative port 207 and the modulation / demodulation 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 214 and 215 are located in the positive port 206 and the negative port 207, their locations may differ between ports. Also, when RTDs 214 and 215 are located in the positive port 206 and the negative port 207, RTDs 214 and 215 may be RTDs of the same structure or RTDs of different structures. Furthermore, the voltage applied to RTDs 214 and 215 and the resonators connected to them may be the same configuration or different configurations.

[0072] Next, with reference to Figure 14, the case in which the above-described communication device 101 is 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. Each of the above configurations of the communication device 101 can function as a receiving device and a transmitting device in a communication system as shown in Figure 14.

[0073] The disclosures herein include the following communication devices and communication systems:

[0074] (Item 1) A communication device comprising a baseband signal processing unit, a common-mode signal processing unit and a quadrature signal processing unit that modulate or demodulate an input signal, a balanced antenna having a first port and a second port, and a phase compensation unit that outputs a signal with the phase of the input signal compensated, 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 orthogonal signal processing unit. The first port and the second port have opposite polarities. The communication device is characterized in that the phase compensation unit is arranged in the baseband signal processing unit, the first path, or the second path.

[0075] (Item 2) The communication device according to item 1, characterized in that the phase compensation unit compensates for the phase of either the signal passing through the first path or the signal passing through the second path.

[0076] (Item 3) The communication device according to item 1 or 2, characterized in that the phase compensation unit is arranged in the first path or the second path and inverts the phase of the input signal.

[0077] (Item 4) The communication device according to item 3, characterized in that the phase compensation unit is arranged between the baseband signal processing unit and the in-phase signal processing unit, or between the baseband signal processing unit and the quadrature signal processing unit.

[0078] (Item 5) The communication device according to item 3, characterized in that the phase compensation unit is arranged between the in-phase signal processing unit and the first port, or between the quadrature signal processing unit and the second port.

[0079] (Item 6) It further includes a carrier wave generation unit that generates a carrier wave, The in-phase signal processing unit and the quadrature signal processing unit each process the signals input to them according to the carrier wave. The communication device according to item 5, characterized in that the phase compensation unit is a transmission line with a length that is an odd multiple of half the wavelength of the carrier wave.

[0080] (Item 7) The aforementioned phase compensation unit, It is located in the aforementioned baseband signal processing unit, The phase of the signal output from the baseband signal processing unit to the first path and the phase of the signal input from the first path to the baseband signal processing unit are inverted, or The communication device according to item 1 or 2, characterized in that it inverts the phase of the signal output from the baseband signal processing unit to the second path and the phase of the signal input from the second path to the baseband signal processing unit.

[0081] (Item 8) It further includes a carrier wave generation unit that generates a carrier wave, The communication device according to item 7, characterized in that the in-phase signal processing unit and the orthogonal signal processing unit each process the signals input to them according to the carrier wave.

[0082] (Item 9) The communication device according to item 6 or 8, characterized in that the carrier wave generation unit generates terahertz waves.

[0083] (Item 10) The communication device according to any one of items 6, 8, and 9, characterized in that the carrier wave generation unit includes a resonant tunneling diode or a CMOS inverter.

[0084] (Item 11) When transmitting a signal, the phase of the signal input to the first port via the first path is in an inverse phase relationship with respect to the phase of the first baseband signal input to the baseband signal processing unit, and the phase of the signal input to the second port via the second path is in an inverse phase relationship with respect to the phase of the first baseband signal. A communication device according to any one of items 1 to 10, characterized in that, when receiving a signal, the phase of the signal input from the first port to the first path is in an inverse phase relationship with respect to the phase of the second baseband signal output from the baseband signal processing unit, and the phase of the signal input from the second port to the second path is in an inverse phase relationship with respect to the phase of the second baseband signal.

[0085] (Item 12) The communication device according to any one of items 1 to 11, characterized in that the balanced antenna includes a patch antenna, a dipole antenna, a slot antenna, or a bowtie antenna.

[0086] (Item 13) A communication device according to any one of items 1 to 12, further comprising at least one of the following: a first reverse current prevention unit disposed between the in-phase signal processing unit and the first port to prevent signals passing through the second path from being input to the in-phase signal processing unit; and a second reverse current prevention unit disposed between the orthogonal signal processing unit and the second port to prevent signals passing through the first path from being input to the orthogonal signal processing unit.

[0087] (Item 14) The communication device according to any one of items 1 to 13, further comprising an amplitude compensation unit for compensating the amplitude of a signal in the first path and the second path, respectively.

[0088] (Item 15) A communication device according to any one of items 1 to 14, 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.

[0089] (Item 16) 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 15, characterized in that when the resonant tunneling diode is connected to the second path between the orthogonal signal processing unit and the second port, the resonant tunneling diode synchronizes with the orthogonal signal processed by the common-mode signal processing unit.

[0090] (Item 17) A communication system comprising a transmitting device and a receiving device, A communication system characterized in that at least one of the transmitting device and the receiving device includes a communication device described in any one of items 1 to 16.

[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: Communication device, 201: Baseband signal processing unit, 202: Common-mode signal processing unit, 203: Quadrature signal processing unit, 204: Balanced antenna, 205: Phase compensation unit, 206: Positive port, 207: Negative port, 208, 209: Path

Claims

1. A communication device comprising a baseband signal processing unit, a common-mode signal processing unit and a quadrature signal processing unit that modulate or demodulate an input signal, a balanced antenna having a first port and a second port, and a phase compensation unit that outputs a signal with the phase of the input signal compensated, 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. The communication device is characterized in that the phase compensation unit is arranged in the baseband signal processing unit, the first path, or the second path.

2. The communication device according to claim 1, characterized in that the phase compensation unit compensates for the phase of either the signal passing through the first path or the signal passing through the second path.

3. The communication device according to claim 1, wherein the phase compensation unit is arranged in the first path or the second path and inverts the phase of the input signal.

4. The communication device according to claim 3, characterized in that the phase compensation unit is arranged between the baseband signal processing unit and the in-phase signal processing unit, or between the baseband signal processing unit and the orthogonal signal processing unit.

5. The communication device according to claim 3, characterized in that the phase compensation unit is disposed between the in-phase signal processing unit and the first port, or between the orthogonal signal processing unit and the second port.

6. It further includes a carrier wave generation unit that generates a carrier wave, The in-phase signal processing unit and the quadrature signal processing unit each process the signals input to them according to the carrier wave. The communication device according to claim 5, characterized in that the phase compensation unit is a transmission line with a length that is an odd multiple of half the wavelength of the carrier wave.

7. The aforementioned phase compensation unit, It is located in the aforementioned baseband signal processing unit, The phase of the signal output from the baseband signal processing unit to the first path and the phase of the signal input from the first path to the baseband signal processing unit are inverted, or The communication device according to claim 1, characterized in that the phase of the signal output from the baseband signal processing unit to the second path and the phase of the signal input from the second path to the baseband signal processing unit are inverted.

8. It further includes a carrier wave generation unit that generates a carrier wave, The communication device according to claim 7, characterized in that the in-phase signal processing unit and the orthogonal signal processing unit each process signals input according to the carrier wave.

9. The communication device according to claim 6, characterized in that the carrier wave generation unit generates terahertz waves.

10. The communication device according to claim 6, characterized in that the carrier wave generation unit includes a resonant tunneling diode or a CMOS inverter.

11. When transmitting a signal, the phase of the signal input to the first port via the first path is in an inverse phase relationship with respect to the phase of the first baseband signal input to the baseband signal processing unit, and the phase of the signal input to the second port via the second path is in an inverse phase relationship with respect to the phase of the first baseband signal. The communication device according to claim 1, characterized in that, when receiving a signal, the phase of the signal input from the first port to the first path is in an inverse phase relationship with respect to the phase of the second baseband signal output from the baseband signal processing unit, and the phase of the signal input from the second port to the second path is in an inverse phase relationship with respect to the phase of the second baseband signal.

12. The communication device according to claim 1, characterized in that the balanced antenna includes a patch antenna, a dipole antenna, a slot antenna, or a bowtie antenna.

13. The communication device according to claim 1, further comprising at least one of the following: a first reverse current prevention unit disposed between the in-phase signal processing unit and the first port to prevent signals passing through the second path from being input to the in-phase signal processing unit; and a second reverse current prevention unit disposed between the orthogonal signal processing unit and the second port to prevent signals passing through the first path from being input to the orthogonal signal processing unit.

14. The communication device according to claim 1, further comprising amplitude compensation units for compensating the amplitude of signals in the first path and the second path, respectively.

15. 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.

16. 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 15, characterized in that when the resonant tunneling diode is connected to the second path between the orthogonal signal processing unit and the second port, the resonant tunneling diode synchronizes with the orthogonal signal processed by the common-mode signal processing unit.

17. A communication system comprising a transmitting device and a receiving device, A communication system characterized in that at least one of the transmitting device and the receiving device includes a communication device according to any one of claims 1 to 16.

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