Terahertz adaptive power control method and system based on bias control modulator

Abstract

The application discloses a terahertz adaptive power control method and system based on a bias control modulator, relates to the technical field of terahertz wireless communication, and solves the technical problem that the prior art cannot actively control the radio frequency front-end power in real time, at a high speed and without loss under a complex dynamic channel environment; the application comprises the following steps: setting a terahertz modulator at a receiving end of a terahertz link; after a receiving antenna of the receiving end receives a terahertz signal, the terahertz signal is adaptively attenuated by the terahertz modulator, so that the power of the terahertz signal is at a target power; the target power is a power range in which the performance of the terahertz link is best after testing; while the power is stable, the application ensures that the throughput and the bit error rate performance of the communication link are not affected.

Description

Technical Field

[0001] This invention relates to the field of terahertz wireless communication technology, and more specifically to a terahertz adaptive power control method and system based on a bias-controlled modulator. Background Technology

[0002] Terahertz (THz) frequency bands (0.1 THz - 10 THz) are a core technology direction for future sixth-generation mobile communication (6G), offering transmission rates on the order of Tbps thanks to their extremely wide spectrum resources. However, in practical terahertz wireless transmission links, signals are highly susceptible to severe environmental factors. Due to the extremely short wavelength of terahertz waves, they face severe path loss during atmospheric transmission, resonant absorption by oxygen and water vapor, and atmospheric fading caused by weather changes. Furthermore, because terahertz beams are extremely narrow, even slight displacements or pointing deviations between the communicating parties can cause drastic fluctuations in received power.

[0003] At the receiver hardware level, terahertz RF front-end devices exhibit high input power sensitivity:

[0004] 1. Limited Dynamic Range: In pursuit of extremely low noise figures, terahertz LNAs typically operate in the voltage-sensitive region, resulting in a narrow linear input power range. When a sudden high-power signal occurs due to interference or shortened distance in the link, the LNA will quickly enter the strongly nonlinear saturation region, causing severe gain compression and third-order intermodulation distortion, leading to rotation and dispersion in the communication constellation diagram.

[0005] 2. Risk of physical damage: Terahertz front-end devices are mostly based on advanced nanoscale Schottky junctions or ultra-short channel HEMT processes, which have extremely low power tolerance. Overload power may directly cause the junctions inside the chip to break down, resulting in irreversible physical damage. Moreover, such core devices are expensive and difficult to replace.

[0006] Existing solutions and their limitations:

[0007] 1. Mechanical waveguide attenuators: Although they have a large adjustment range, they rely on stepper motors to adjust mechanical dimensions, and their response speed is mostly in the second range. They cannot track fast fading in the millisecond range. In addition, they are bulky and subject to mechanical wear, making them unsuitable for mobile communication platforms.

[0008] 2. Baseband Automatic Gain Control (AGC): Primarily performs gain compensation in the digital domain. While it can stabilize the baseband signal amplitude, it cannot change the physical fact that the RF front-end LNA has already saturated or burned out. It is a reactive compensation and lacks substantial protection for the analog front-end.

[0009] 3. Traditional intermediate frequency attenuation scheme: The adjustment unit is placed after the downconversion. Although it can stabilize the intermediate frequency output, it still cannot solve the nonlinear distortion problem of RF front-end devices under large signal input.

[0010] Therefore, how to actively control the power of the radio frequency front-end in real time, at high speed and without loss in complex dynamic channel environments has become a key challenge for the engineering implementation of terahertz communication. Summary of the Invention

[0011] To address the problems existing in the prior art, this invention provides a terahertz adaptive power control method and system based on a bias-controlled modulator. This solves the technical problem that existing technologies cannot actively manage RF front-end power in real-time, at high speed, and without loss in complex dynamic channel environments. When the channel environment changes, the spatial loss of the channel is most affected. This invention responds to channel changes by detecting these changes and adjusting the modulator's bias voltage to regulate its attenuation value.

[0012] A terahertz adaptive power control method based on a bias-controlled modulator includes:

[0013] A terahertz modulator is set at the receiving end of the terahertz link. After the receiving antenna at the receiving end receives the terahertz signal, the terahertz modulator adaptively attenuates the terahertz signal so that the power of the terahertz signal is at the target power, which is the power that optimizes the overall performance of the terahertz link as determined by test analysis.

[0014] Furthermore, the adaptive attenuation of the terahertz signal by the terahertz modulator includes: determining the real-time power of the terahertz signal output by the receiver, calculating the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, determining the bias voltage based on the deviation, inputting the bias voltage to the DC bias control terminal of the terahertz modulator, and adjusting the transmission attenuation of the terahertz wave so that the terahertz signal output by the receiver is stabilized at the target power.

[0015] Further, determining the bias voltage based on the deviation includes: determining whether the deviation exceeds the tolerance range; if it does, first determining the amount of RF transmission attenuation required to offset the deviation, and then searching in reverse in the bias-attenuation mapping lookup table of the terahertz modulator obtained from the test to find the bias voltage corresponding to the amount of RF transmission attenuation.

[0016] Furthermore, the determination of the power deviation-bias voltage lookup table includes: determining the operating frequency of the terahertz link, determining the terahertz modulator with the operating frequency as the center frequency, scanning the bias voltage of the terahertz modulator, using a vector network analyzer to characterize the change curve of the RF transmission coefficient under different bias voltages, obtaining the corresponding RF transmission attenuation under different bias voltages, and constructing and solidifying a nonlinear bias-attenuation mapping relationship lookup table.

[0017] A terahertz adaptive power control system based on a bias-controlled modulator includes a terahertz modulator and a closed-loop feedback unit. The terahertz modulator is located at the receiving end of the terahertz link, serving as the next-stage device after the receiving antenna, and adjusts the power of the terahertz signal just entering the receiving end. The closed-loop feedback unit includes functions for detecting the real-time power of the terahertz signal output from the receiving end, calculating the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, determining a bias voltage based on the deviation, and inputting the bias voltage to the DC bias control terminal of the terahertz modulator to adjust the transmission attenuation of the terahertz wave, so that the terahertz signal output from the receiving end is stabilized at the target power.

[0018] Furthermore, the closed-loop feedback unit includes a power detection module, a microprocessor, and a digital-to-analog converter connected in sequence. The power detection module is used to detect the real-time power of the terahertz signal output by the receiver. The microprocessor is used to calculate the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, and to determine the bias voltage based on the deviation. The digital-to-analog converter is used to convert the output of the microprocessor into a digital-to-analog signal and then input it to the DC bias control port of the terahertz modulator.

[0019] Furthermore, the microprocessor has a pre-defined bias-attenuation mapping lookup table for the terahertz modulator. It first determines whether the deviation exceeds the tolerance range. If it does, it first determines the amount of radio frequency transmission attenuation required to offset the deviation, and then searches in reverse in the bias-attenuation mapping lookup table of the terahertz modulator to find the bias voltage corresponding to the amount of radio frequency transmission attenuation.

[0020] The beneficial effects of this invention include:

[0021] 1. This invention deploys a bias-controlled terahertz modulator at the radio frequency front end between the receiving antenna and the low-noise amplifier (LNA). This pre-gated architecture can directly reduce the signal amplitude through physical absorption before the high-energy signal enters the amplification circuit, effectively preventing breakdown damage to the sensitive nanoscale Schottky junctions in the LNA and subsequent mixer caused by large-amplitude pulse signals generated by sudden changes in the link environment.

[0022] Furthermore, by using real-time pre-attenuation, the LNA is ensured to always operate in the optimal linear region, effectively suppressing gain compression and third-order intermodulation distortion caused by signal overload. This solves the inherent problem of terahertz receivers being prone to saturation and difficult to protect from the hardware topology.

[0023] 2. This invention employs a negative feedback control algorithm based on a self-developed voltage-attenuation mapping lookup table (LUT), achieving a balance between dynamic response and control accuracy. Experimental data shows that the system can cover a range of drastic input power fluctuations exceeding 18 dB and compress them to the target power level. Furthermore, through precise compensation of the modulator's nonlinear characteristics using the LUT, the system can strictly control the intermediate frequency power fluctuation range at the receiving end within ±0.3 dB. This high-precision power locking capability provides an extremely stable quantization environment for the subsequent analog-to-digital converter (ADC), significantly improving the system's demodulation efficiency.

[0024] 3. The bias-controlled modulator used in this invention exhibits excellent signal fidelity when implementing wide-range attenuation: due to its superior voltage-controlled linearity over a wide bandwidth of 1.1-1.7 GHz, the modulation process introduces almost no additional phase or amplitude noise. Experimental results show that during full-range modulation, the system's signal-to-noise ratio (SNR) remains stable around 24 dB, and the error vector amplitude (EVM) of the 4-QAM modulated signal consistently remains below 7%. This means that this invention ensures that the throughput and bit error rate performance of the communication link are not affected while stabilizing power.

[0025] 4. Unlike mechanical waveguide attenuators with second-level response, the electronically controlled bias adjustment scheme of this invention has extremely low response delay and can track fast fading caused by rapid movement or blockage in real time. Furthermore, the all-solid-state Schottky component has a compact structure and no mechanical moving parts, which greatly improves the deployment life and reliability of the system on complex mobile platforms such as drones and airborne communications, which are subject to vibration and shock. This provides a mature technical path for the engineering application of future 6G terahertz communication.

[0026] 5. The bias-controlled control logic designed in this invention has strong frequency mobility. By replacing the waveguide components in the corresponding frequency band, the adaptive algorithm and closed-loop architecture of this invention can be quickly applied to terahertz communication systems at 220 GHz, 300 GHz, and even higher frequency bands, demonstrating extremely high industrial applicability. Attached Figure Description

[0027] Figure 1 This is a flowchart of a terahertz adaptive power control method based on a bias-controlled modulator, which is involved in the embodiments of this application.

[0028] Figure 2This is a diagram of the architecture of a terahertz adaptive power control system based on a bias control modulator, as described in an embodiment of this application.

[0029] Figure 3 This is a graph showing the static characteristics (S21 as a function of bias voltage) of the modulator transmission parameters involved in the embodiments of this application.

[0030] Figure 4 This diagram shows the verification effect of the adaptive link attenuation adjustment on the receiver power control in the embodiments of this application.

[0031] Figure 5 This is a signal-to-noise ratio and constellation diagram analysis of the system involved in the power dynamic adjustment process according to the embodiments of this application; Figure 5 (a) shows the changes in the signal-to-noise ratio of the received signal after link adaptive attenuation adjustment under different transmit power conditions. Figure 5 (b) is a constellation diagram of the received signal when the transmit power is low, showing the signal power and bit error rate. Figure 5 (c) is the constellation diagram of the received signal when the transmit power is at a high level, showing the signal power and bit error rate. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] Example 1

[0034] The following is in conjunction with the appendix Figure 1 Specific embodiments of the present invention will be described in detail;

[0035] A terahertz adaptive power control method based on a bias-controlled modulator includes:

[0036] A terahertz modulator is set at the receiving end of the terahertz link. After the receiving antenna at the receiving end receives the terahertz signal, the terahertz modulator adaptively attenuates the terahertz signal so that the power of the terahertz signal is at the target power, which is the power that optimizes the overall performance of the terahertz link as determined by test analysis.

[0037] The adaptive attenuation of the terahertz signal by the terahertz modulator includes: determining the real-time power of the terahertz signal output by the receiver, calculating the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, determining the bias voltage based on the deviation, inputting the bias voltage to the DC bias control terminal of the terahertz modulator, and adjusting the transmission attenuation of the terahertz wave so that the terahertz signal output by the receiver is stabilized at the target power.

[0038] The step of determining the bias voltage based on the deviation includes: determining whether the deviation exceeds the tolerance range; if it does, first determining the amount of RF transmission attenuation required to offset the deviation, and then searching in reverse in the bias-attenuation mapping table of the terahertz modulator obtained from the test to find the bias voltage corresponding to the amount of RF transmission attenuation.

[0039] The determination of the power deviation-bias voltage lookup table includes: determining the operating frequency of the terahertz link, determining the terahertz modulator with the operating frequency as the center frequency, scanning the bias voltage of the terahertz modulator, using a vector network analyzer to characterize the change curve of the RF transmission coefficient under different bias voltages, obtaining the corresponding RF transmission attenuation under different bias voltages, and constructing and solidifying a nonlinear bias-attenuation mapping lookup table.

[0040] Specifically, the implementation process is as follows:

[0041] Based on the power balance equation for terahertz links: Design; among which For the intermediate frequency power at the receiving end, This refers to the intermediate frequency power at the transmitting end. For the system's inherent gain, For dynamic path loss, For the modulator at the bias voltage The physical attenuation. Specifically, as follows: Figure 1 As shown, it includes the following steps:

[0042] Step S1: Scan the bias voltage of the terahertz modulator, covering the dynamic range from 0 V to 1 V. Use a vector network analyzer to characterize the frequency characteristics, i.e., the change curve of the RF transmission coefficient, under different bias voltages. Obtain the RF transmission attenuation corresponding to different bias voltages, and construct and solidify a nonlinear bias-attenuation mapping lookup table (LUT).

[0043] Step S2: The terahertz link enters dynamic communication mode. The receiving antenna of the receiving module captures the terahertz wave, processes it, and outputs it. The power detection module continuously detects the output terahertz signal in real time and extracts the actual received intermediate frequency power at the current moment. .

[0044] Step S3: Collect the data With respect to the preset safe target power threshold of the RF front end Perform differential operations to quantify the power deviation of the current link caused by environmental fading. The convergence and bit error rate of the constellation diagram were tested under different receiver powers to determine the optimal receiver power as the security target power threshold. The optimal receiver power enables the link to achieve the best performance, including convergence, bit error rate, and signal-to-noise ratio.

[0045] Step S4: Determine the absolute value of the power deviation. Whether it exceeds the preset steady-state dead zone tolerance range, which in this embodiment is ±0.3 dB. If it exceeds, then... To compensate for the target, a reverse search is performed in the pre-stored LUT lookup table to find a bias voltage that can accurately offset the link fluctuation. Using a lookup table method instead of real-time nonlinear function calculation ensures extremely low computational latency for the microprocessor. The steady-state dead-zone tolerance range is determined by the power fluctuation range during the testing process. This fluctuation range has little impact on the performance.

[0046] Step S5: Update the new bias voltage The signal is then converted from digital to analog and output to the DC bias control terminal of the terahertz modulator. The modulator instantaneously changes the impedance characteristics of its internal components based on the new bias voltage, physically adjusting the transmission attenuation of the terahertz wave, causing the signal power input to the LNA to drop and stabilize at a certain level. Nearby, a closed-loop adaptive power compensation cycle is completed.

[0047] In another embodiment, a terahertz adaptive power control system based on a bias-controlled modulator is disclosed, comprising a terahertz modulator and a closed-loop feedback unit. The terahertz modulator is located at the receiving end of a terahertz link as a next-stage device of the receiving antenna, adjusting the power of the terahertz signal just entering the receiving end. The closed-loop feedback unit includes functions for detecting the real-time power of the terahertz signal output from the receiving end, calculating the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, determining a bias voltage based on the deviation, and inputting the bias voltage to the DC bias control terminal of the terahertz modulator to adjust the transmission attenuation of the terahertz wave, thereby stabilizing the terahertz signal output from the receiving end at the target power.

[0048] The closed-loop feedback unit includes a power detection module, a microprocessor, and a digital-to-analog converter connected in sequence. The power detection module is used to detect the real-time power of the terahertz signal output by the receiver. The microprocessor is used to calculate the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, and to determine the bias voltage based on the deviation. The digital-to-analog converter is used to convert the output of the microprocessor into a digital-to-analog signal and then input it to the DC bias control port of the terahertz modulator.

[0049] The microprocessor has a pre-set bias-attenuation mapping lookup table for the terahertz modulator. It first determines whether the deviation exceeds the tolerance range. If it does, it first determines the amount of RF transmission attenuation required to offset the deviation, and then searches in reverse in the bias-attenuation mapping lookup table for the terahertz modulator to find the bias voltage corresponding to the amount of RF transmission attenuation.

[0050] Specifically, the terahertz link in this application is as follows: Figure 2 As shown, the system includes a signal transmission chain and a signal receiving chain. The signal transmission chain comprises a first driving signal source (140GHz / 8), a first frequency multiplier power amplifier, an up-conversion mixer, a final-stage power amplifier, and a high-gain directional transmitting antenna, all electrically connected in sequence. The first driving signal source outputs a local oscillator signal. The 140 GHz up-conversion mixer is connected to the baseband and performs up-conversion mixing on the frequency multiplied local oscillator signal and the intermediate frequency signal input from the baseband. The mixed signal is then amplified by the power amplifier and boosted to the terahertz band before being radiated into free space through the directional antenna.

[0051] The signal receiving chain includes a receiving antenna, a terahertz modulator, a low-noise amplifier, and a down-conversion mixer connected in sequence. The down-conversion mixer is also connected to a baseband and a second frequency-doubled power amplifier source. The second frequency-doubled power amplifier source is connected to a second drive signal source (139GHz / 8). The local oscillator signal output by the second drive signal source is multiplied by the second frequency-doubled power amplifier source and then input to the down-conversion mixer. The terahertz signal received by the receiving antenna is passed through a bias-controlled terahertz modulator and a low-noise amplifier in sequence and then input to the down-conversion mixer. The down-conversion mixer performs down-conversion mixing on the received terahertz signal and the local oscillator signal and outputs an intermediate frequency signal to the baseband.

[0052] Both the first and second frequency multiplier power amplifier sources use AMC5585. The upconverter mixer is a 140GHz upconverter mixer, and the downconverter mixer is a 140GHz downconverter mixer.

[0053] The input terminal of the power detection module is connected to the output terminal of the downconverter mixer, the output terminal of the power detection module is connected to the input terminal of the microprocessor, and the output terminal of the microprocessor is connected to the DC bias control port of the terahertz modulator via a digital-to-analog converter.

[0054] The bias-controlled terahertz modulator has an RF input terminal, an RF output terminal, and a DC bias control port. The RF input terminal is directly connected to the receiving antenna via a standard WR-06 waveguide flange, and the RF output terminal is directly connected to the input terminal of the low-noise amplifier. In the system, the bias-controlled terahertz modulator acts as an adaptive attenuation gate, adjusting the bias voltage by detecting the received power to adaptively attenuate the signal, performing physical-level amplitude modulation before the RF signal enters the sensitive LNA.

[0055] The technical details and experimental effects of the present invention will be further described below with reference to the embodiments and system-level experimental data.

[0056] This system adopts a 140GHz high-bandwidth terahertz communication architecture. The hardware interfaces at both the transceiver and receiver ends use standard WR-06 waveguide packages to reduce transmission loss in the ultra-high frequency band, and are integrated on a precision pan-tilt unit with multi-degree-of-freedom adjustment capabilities to ensure that the antenna beam main lobe is perfectly aligned.

[0057] During the system deployment phase, the modulator's static characteristics were characterized, and a LUT table was constructed. Vector Network Analyzer (VNA) testing showed that, as Figure 3 As shown, as the bias voltage increases from 0V to 1V, the device exhibits a dynamic monotonic attenuation capability of more than 15dB at the center frequency of 1.4GHz.

[0058] In the experimental verification of the system's adaptive control, a target power threshold of -35.5dBm was preset. Drastic fluctuations in link power were then simulated (by gradually increasing the transmit power from -36dBm to -18dBm, a span of 18dB). At this point, the microprocessor detected the change, quickly looked up the mapping table, and drove the bias voltage of the terahertz modulator from 0V to 1V, causing its corresponding attenuation to increase synchronously from -4dB to -23.17dB. Experimental results showed that the adaptively adjusted receiver intermediate frequency power remained stable, with fluctuations precisely controlled within ±0.3dB. Specifically, as shown below... Figure 4 As shown. Based on Figure 4 The test data is shown in the table below, which illustrates the decision-making logic of the algorithm under different transmit power conditions:

[0059] Table 1. Bias voltage decision logic under different transmit power conditions.

[0060]

[0061] like Figure 5 As shown, Figure 5 (a) shows the changes in the signal-to-noise ratio of the received signal after link adaptive attenuation adjustment under different transmit power conditions. Figure 5(b) is a constellation diagram of the received signal when the transmit power is low, showing the signal power and bit error rate. Figure 5 (c) shows the constellation diagram of the received signal when the transmit power is at a high level, along with the signal power and bit error rate. As can be seen from the figure, during this wide-range dynamic adjustment period, in the communication quality assessment, even when the system is in the maximum attenuation state (1V bias), the 4-QAM constellation diagram still converges well, the EVM (RMS) index remains between 6.13% and 6.90% (both far below the 17.5% limit), and the signal-to-noise ratio (SNR) remains stable around 24dB. This experimentally verifies that when this invention is used as a high-performance solid-state continuously variable attenuator, it can achieve precise and real-time control of terahertz link power without sacrificing SNR and bit error rate performance. In summary, this invention not only verifies the superior performance of solid-state terahertz modulators as adaptive attenuation actuators but also provides important algorithmic support for the intelligent link management of future terahertz communication systems.

[0062] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A terahertz adaptive power control method based on a bias-controlled modulator, characterized in that, include: A terahertz modulator is set at the receiving end of the terahertz link. After the receiving antenna at the receiving end receives the terahertz signal, the terahertz modulator adaptively attenuates the terahertz signal so that the power of the terahertz signal is at the target power.

2. The terahertz adaptive power control method based on a bias-controlled modulator according to claim 1, characterized in that, The adaptive attenuation of the terahertz signal by the terahertz modulator includes: determining the real-time power of the terahertz signal output by the receiver, calculating the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, determining the bias voltage based on the deviation, inputting the bias voltage to the DC bias control terminal of the terahertz modulator, and adjusting the transmission attenuation of the terahertz wave so that the terahertz signal output by the receiver is stabilized at the target power.

3. The terahertz adaptive power control method based on a bias-controlled modulator according to claim 2, characterized in that, The step of determining the bias voltage based on the deviation includes: determining whether the deviation exceeds the tolerance range; if it does, first determining the amount of RF transmission attenuation required to offset the deviation, and then searching in reverse in the bias-attenuation mapping table of the terahertz modulator obtained from the test to find the bias voltage corresponding to the amount of RF transmission attenuation.

4. The terahertz adaptive power control method based on a bias-controlled modulator according to claim 3, characterized in that, The determination of the power deviation-bias voltage lookup table includes: determining the operating frequency of the terahertz link, determining the terahertz modulator with the operating frequency as the center frequency, scanning the bias voltage of the terahertz modulator, using a vector network analyzer to characterize the change curve of the RF transmission coefficient under different bias voltages, obtaining the corresponding RF transmission attenuation under different bias voltages, and constructing and solidifying a nonlinear bias-attenuation mapping lookup table.

5. A terahertz adaptive power control system based on a bias-controlled modulator, characterized in that, The device includes a terahertz modulator and a closed-loop feedback unit. The terahertz modulator is located at the receiving end of the terahertz link and serves as the next-stage device after the receiving antenna. It adjusts the power of the terahertz signal that just enters the receiving end. The closed-loop feedback unit includes a function to detect the real-time power of the terahertz signal output from the receiving end, calculate the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, determine the bias voltage based on the deviation, and input the bias voltage to the DC bias control terminal of the terahertz modulator to adjust the transmission attenuation of the terahertz wave, so that the terahertz signal output from the receiving end is stabilized at the target power.

6. The terahertz adaptive power control system based on a bias-controlled modulator according to claim 5, characterized in that, The closed-loop feedback unit includes a power detection module, a microprocessor, and a digital-to-analog converter connected in sequence. The power detection module is used to detect the real-time power of the terahertz signal output by the receiver. The microprocessor is used to calculate the deviation between the real-time power and the target power as the power fluctuation affected by channel changes, and to determine the bias voltage based on the deviation. The digital-to-analog converter is used to convert the output of the microprocessor into a digital-to-analog signal and then input it to the DC bias control port of the terahertz modulator.

7. The terahertz adaptive power control system based on a bias-controlled modulator according to claim 6, characterized in that, The microprocessor has a pre-set bias-attenuation mapping lookup table for the terahertz modulator. It first determines whether the deviation exceeds the tolerance range. If it does, it first determines the amount of RF transmission attenuation required to offset the deviation, and then searches in reverse in the bias-attenuation mapping lookup table for the terahertz modulator to find the bias voltage corresponding to the amount of RF transmission attenuation.

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