Electroscanning radiometer device based on metasurface coded antenna

Abstract

The application provides an electric scanning radiometer device based on a metasurface coding antenna, comprising: a metasurface coding antenna unit, a receiving end of the metasurface coding antenna unit receiving microwave radiation signals from a target scene; a radiometer receiving channel connected with an output end of the metasurface coding antenna unit, receiving the microwave radiation signals and outputting stable radiation power signals; an AD collector connected with an output end of the radiometer receiving channel, receiving the radiation power signals and converting the radiation power signals into digital signals; a computer connected with an output end of the AD collector, receiving and storing the digital signals and performing imaging processing according to the digital signals; and the computer is also connected with a control end of the metasurface coding antenna unit, and transmits a beam scanning angle instruction to the metasurface coding antenna unit. The coding phased electric scanning mode of the application has the advantages of fast scanning speed, simple and light system structure and economical cost compared with the existing real-aperture radiometer device.

Description

Technical Field

[0001] This invention relates to the field of radiometer technology, and more specifically, to an electrically scanned radiometer based on a metasurface coded antenna. Background Technology

[0002] A radiometer is a passive testing instrument used to measure the microwave radiation energy of an object, and it is widely used in remote sensing, radio astronomy, and other fields. With advancements in sensor technology and signal processing technology, modern radiometers have not only seen significant improvements in sensitivity and accuracy, but also in portability, data recording capabilities, and wireless transmission functions. High-precision radiometers have become indispensable tools. Among them, the real-aperture radiometer is used to measure the power of the microwave thermal radiation signal generated by the observed scene and the target itself. By measuring data from the observed scene and target in the horizontal and vertical directions, it enables the reconstruction and imaging of the radiation brightness and temperature distribution of the observed scene and target.

[0003] Currently, the typical components of a real aperture radiometer device that is widely used both domestically and internationally include a real aperture radiometer antenna, a receiving channel, and an AD acquisition unit, all mounted and fixed on a mechanical turntable. The mechanical turntable is controlled by a computer to achieve two-dimensional scanning measurements of the observation scene in the horizontal and vertical directions by the real aperture radiometer (antenna + receiving channel). The measurement data from the AD acquisition unit is processed to reconstruct the radiation brightness temperature distribution of the observation scene.

[0004] Based on the aforementioned development status, the applicant discovered that existing real aperture radiometer devices still have significant errors. Research revealed that these errors are primarily caused by the traditional real aperture radiometer device's requirement to use a mechanical turntable for two-dimensional mechanical scanning of the observation scene and target to reconstruct the radiation brightness temperature distribution. This introduces mechanical errors from the turntable during the imaging measurement process, resulting in degraded image quality. Furthermore, the mechanical scanning device also complicates the real aperture radiometer device and increases imaging measurement time. Summary of the Invention

[0005] The present invention aims to solve at least one of the aforementioned technical problems existing in the prior art.

[0006] Therefore, the present invention provides an electrically scanned radiometer device based on a metasurface coded antenna.

[0007] This invention provides an electrically scanned radiometer device based on a metasurface coded antenna, comprising:

[0008] A metasurface coded antenna unit has a receiving end, an output end, and a control end. The receiving end of the metasurface coded antenna unit receives microwave radiation signals from a target scene.

[0009] The radiometer receiving channel is connected to the output terminal of the metasurface coded antenna unit, receives the microwave radiation signal, processes the microwave radiation signal, and outputs a stable radiation power signal.

[0010] The AD acquisition unit is connected to the output terminal of the radiometer receiving channel, receives the radiation power signal and converts the radiation power signal into a digital signal;

[0011] A computer is connected to the output terminal of the AD acquisition unit to receive and store the digital signals and perform imaging processing based on the digital signals. The computer is also connected to the control terminal of the metasurface coded antenna unit to transmit beam scanning angle commands to the metasurface coded antenna unit. The beam scanning angle commands are used to control the beam pointing of the metasurface coded antenna unit in the horizontal and vertical directions for adjustment and electronic scanning.

[0012] The electrically scanned radiometer device based on a metasurface coded antenna according to the above-described technical solution of the present invention may further have the following additional technical features:

[0013] In the above technical solution, the metasurface coded antenna element includes:

[0014] A transmissive metasurface coded array antenna has a receiving end, an output end, and a control end. The receiving end of the transmissive metasurface coded array antenna serves as the receiving end of a metasurface coded antenna element, and the output end of the transmissive metasurface coded array antenna serves as the output end of a metasurface coded antenna element.

[0015] A voltage control module has an input terminal and an output terminal, wherein the output terminal of the voltage control module is coupled to the control terminal of the transmissive metasurface coded array antenna;

[0016] The encoding control module has an input terminal and an output terminal. The input terminal of the encoding control module is connected to a computer to receive the beam scanning angle command, and the output terminal of the encoding control module is coupled to the input terminal of the voltage control module.

[0017] The encoding control module controls the output voltage of the voltage control module according to the received beam scanning angle command, thereby realizing the adjustment and electrical scanning of the beam pointing of the transmissive metasurface encoded array antenna in the horizontal and vertical directions.

[0018] In the above technical solution, the radiometer receiving channel includes:

[0019] A radio frequency amplifier, coupled to the output of the transmissive metasurface coded array antenna, is used to amplify the millimeter-wave signal received by the antenna.

[0020] A square-law detector, connected to the radio frequency amplifier, is used to convert the amplified millimeter-wave signal into a DC signal;

[0021] A low-pass filter, connected to the square-law detector, is used to filter out high-frequency noise in the output signal of the square-law detector.

[0022] An integrator, connected to the low-pass filter, is used to integrate the signal output by the low-pass filter to obtain the radiated power signal.

[0023] In the above technical solution, during the beam scanning of the target scene, when the beam of the transmissive metasurface coded array antenna is tuned to a specified angle, the coding control module will send a signal to the computer that the beam has been tuned. At this time, the computer will control the AD acquisition unit to collect and store the radiation power signal output by the radiometer receiving channel.

[0024] The above technical solution also includes:

[0025] An image display unit, connected to the computer, is used to display the imaging processing results.

[0026] In the above technical solution, the radio frequency amplifier is a low-noise amplifier with a noise figure of less than 4dB and a gain of more than 20dB, so as to minimize the noise introduced by the microwave radiation signal during the amplification process and improve the sensitivity of the system.

[0027] In the above technical solution, the square-law detector uses a Schottky diode, which has high linearity and low insertion loss, and can accurately convert the amplified millimeter-wave signal into a DC signal, reducing signal distortion.

[0028] In the above technical solution, the cutoff frequency of the low-pass filter is 1MHz, and the out-of-band rejection is greater than 30dB, which can effectively filter out high-frequency noise and ensure that the signal processed by the integrator is smooth and stable.

[0029] In the above technical solution, the integration time of the integrator is adjustable, ranging from 1μs to 20μs, to adapt to the radiation signal intensity of different target scenarios and improve the signal-to-noise ratio and response speed of the measurement.

[0030] In the above technical solution, the encoding control module is implemented using a field-programmable gate array, which can quickly respond to the beam scanning angle command of the computer and accurately control the output voltage of the voltage control module to achieve high-precision beam pointing control.

[0031] In summary, due to the adoption of the above-mentioned technical features, the beneficial effects of the present invention are:

[0032] The electronically scanned radiometer device based on a metasurface coded antenna provided by this invention can effectively solve the problems of measurement error, long measurement time and system complexity caused by mechanical turntable in existing solid aperture radiometer devices. Compared with existing solid aperture radiometer devices, the coded phased electronic scanning method of this invention has the advantages of fast scanning speed, simple and lightweight system structure and economical cost.

[0033] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0035] Figure 1 This is a schematic diagram of an electrically scanned radiometer device based on a metasurface coded antenna according to an embodiment of the present invention.

[0036] in, Figure 1 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0037] 1. Transmissive metasurface coded array antenna; 2. Voltage control module; 3. Encoding control module; 4. RF amplifier; 5. Square-law detector; 6. Low-pass filter; 7. Integrator; 8. AD acquisition unit; 9. Computer; 10. Image display unit. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0040] The following reference Figure 1 This describes an electrically scanned radiometer device based on a metasurface coded antenna provided according to some embodiments of the present invention.

[0041] Some embodiments of this application provide an electrically scanned radiometer device based on a metasurface coded antenna.

[0042] like Figure 1As shown, the first embodiment of the present invention proposes an electrically scanned radiometer device based on a metasurface coded antenna, comprising: a metasurface coded antenna unit, a radiometer receiving channel, an AD acquisition unit 8, and a computer 9.

[0043] The metasurface coded antenna unit has a receiving end, an output end, and a control end. The receiving end of the metasurface coded antenna unit receives microwave radiation signals from the target scene. It should be noted that the metasurface coded antenna unit is used to implement coded phased electronic scanning.

[0044] The radiometer receiving channel is connected to the output terminal of the metasurface coded antenna unit, receives the microwave radiation signal, processes the microwave radiation signal, and outputs a stable radiation power signal.

[0045] The AD acquisition unit 8 is connected to the output terminal of the radiometer receiving channel, receives the radiation power signal, and converts the radiation power signal into a digital signal.

[0046] Computer 9 is connected to the output terminal of AD acquisition unit 8, receives and stores the digital signal, and performs imaging processing based on the digital signal; computer 9 is also connected to the control terminal of the metasurface coded antenna unit, and transmits beam scanning angle command to the metasurface coded antenna unit. The beam scanning angle command is used to control the beam pointing of the metasurface coded antenna unit in the horizontal and vertical directions for adjustment and electronic scanning.

[0047] In some embodiments, the metasurface coded antenna unit includes a transmissive metasurface coded array antenna 1, a voltage control module 2, and a coding control module 3.

[0048] The transmissive metasurface coded array antenna 1 has a receiving end, an output end, and a control end. The receiving end of the transmissive metasurface coded array antenna 1 serves as the receiving end of a metasurface coded antenna element, and the output end of the transmissive metasurface coded array antenna 1 serves as the output end of a metasurface coded antenna element. Specifically, the transmissive metasurface coded array antenna 1 utilizes the properties of a metasurface to control the propagation of electromagnetic waves. The transmissive metasurface coded array antenna 1 controls the transmission phase of electromagnetic waves through a coding sequence, thereby achieving functions such as beam directionality, focusing, or multi-beam generation. This antenna features high gain, high sensitivity, thinness, and reconfigurability, making it suitable for applications with limited space.

[0049] The voltage control module 2 has an input terminal and an output terminal, and the output terminal of the voltage control module 2 is coupled to the control terminal of the transmissive metasurface coded array antenna 1.

[0050] The encoding control module 3 has an input terminal and an output terminal. The input terminal of the encoding control module 3 is connected to the computer 9 to receive the beam scanning angle command. The output terminal of the encoding control module 3 is coupled to the input terminal of the voltage control module 2.

[0051] In this embodiment, the encoding control module 3 controls the output voltage of the voltage control module 2 according to the received beam scanning angle command, thereby realizing the adjustment and electrical scanning of the beam pointing of the transmissive metasurface encoded array antenna 1 in the horizontal and vertical directions.

[0052] In some embodiments, during beam scanning of the target scene, when the beam of the transmissive metasurface coded array antenna 1 is tuned to a specified angle, the coding control module 3 sends a signal to the computer 9 indicating that the beam has been tuned. At this time, the computer 9 controls the AD acquisition unit 8 to acquire and store the radiated power signal output from the radiometer receiving channel. The above measurement process is repeated until the AD acquisition unit 8 completes the acquisition of the signal corresponding to the scanned area of ​​the target scene, after which the computer 9 performs imaging processing on the stored data.

[0053] In some embodiments, the electronically scanned radiometer device further includes an image display unit 10, which is connected to the computer 9 and is used to display imaging processing results. In one specific embodiment, the image display unit 10 is configured as a high-definition display.

[0054] In some embodiments, continue reading Figure 1 The radiometer receiving channel includes: a radio frequency amplifier 4, a square-law detector 5, a low-pass filter 6, and an integrator 7.

[0055] Radio frequency (RF) amplifier 4, coupled to the output of the transmissive metasurface coded array antenna 1, amplifies the millimeter-wave signal received by the antenna. Specifically, the main function of RF amplifier 4 is to amplify the weak RF signal received from the antenna to a sufficient level for effective processing by subsequent circuitry. It typically has high gain and a low noise figure to ensure that excessive noise is not introduced during signal amplification, thereby guaranteeing system sensitivity. In one specific embodiment, RF amplifier 4 is a low-noise amplifier with a noise figure less than 4 dB and a gain greater than 20 dB to minimize noise introduced during microwave radiation signal amplification and improve system sensitivity.

[0056] The square-law detector 5 is connected to the radio frequency amplifier 4 and is used to convert the amplified millimeter-wave signal into a DC signal. Specifically, the square-law detector 5 converts the amplitude information of the radio frequency signal into a DC voltage or current signal. It extracts the power information of the signal through squaring operations, thereby realizing the measurement of radiated power. In the radiometer, the square-law detector 5 converts the amplified radio frequency signal into a DC signal for subsequent processing by the integrator 7. The output signal of the square-law detector 5 fluctuates rapidly, so it needs to be smoothed by the integrator 7. In a specific embodiment, the square-law detector 5 uses a Schottky diode, which has high linearity and low insertion loss, and can accurately convert the amplified millimeter-wave signal into a DC signal, reducing signal distortion.

[0057] Low-pass filter 6 is connected to the square-law detector 5 and is used to filter out high-frequency noise in the output signal of the square-law detector 5. Specifically, the function of low-pass filter 6 is to filter out high-frequency noise and unwanted high-frequency components, retaining only the low-frequency signal. It ensures that the detected signal is smooth before processing by integrator 7, thereby improving the signal-to-noise ratio. In the radiometer receiving channel, low-pass filter 6 filters out high-frequency noise in the output signal of square-law detector 5, making the signal smoother and facilitating integration processing by integrator 7. In a specific embodiment, the cutoff frequency of low-pass filter 6 is 1MHz, and the out-of-band rejection is greater than 30dB, which can effectively filter out high-frequency noise and ensure that the signal processed by integrator 7 is smooth and stable.

[0058] Integrator 7 is connected to the low-pass filter 6 and is used to integrate the signal output by the low-pass filter 6 to obtain the radiated power signal. Specifically, the function of integrator 7 is to integrate the signal output by the low-pass filter 6 over time, thereby obtaining the average value over a certain time range. Integrator 7 can effectively reduce short-term signal fluctuations and improve measurement stability and signal-to-noise ratio. In the radiometer, integrator 7 integrates the signal output by the low-pass filter 6 to obtain the average value of the radiated power. The integration time affects the measurement accuracy and response speed; a longer integration time can improve the signal-to-noise ratio but will reduce the system's response speed. In a specific embodiment, the integration time of integrator 7 is adjustable, ranging from 1 μs to 20 μs, to adapt to the radiated signal intensity of different target scenarios and improve the measurement signal-to-noise ratio and response speed.

[0059] In some embodiments, the encoding control module 3 is implemented using a field-programmable gate array (FPGA), which can quickly respond to the beam scanning angle command of the computer 9 and precisely control the output voltage of the voltage control module 2 to achieve high-precision beam pointing control.

[0060] In this specification, the illustrative expressions of the terms used do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention shall be included within the scope of protection of this invention.

Claims

1. An electrically scanned radiometer device based on a metasurface coded antenna, characterized in that, include: A metasurface coded antenna unit has a receiving end, an output end, and a control end. The receiving end of the metasurface coded antenna unit receives microwave radiation signals from a target scene. The radiometer receiving channel is connected to the output terminal of the metasurface coded antenna unit, receives the microwave radiation signal, processes the microwave radiation signal, and outputs a stable radiation power signal. The AD acquisition unit is connected to the output terminal of the radiometer receiving channel, receives the radiation power signal and converts the radiation power signal into a digital signal; A computer is connected to the output terminal of the AD acquisition unit to receive and store the digital signals and perform imaging processing based on the digital signals; the computer is also connected to the control terminal of the metasurface coded antenna unit to transmit beam scanning angle commands to the metasurface coded antenna unit, the beam scanning angle commands being used to control the beam pointing of the metasurface coded antenna unit in the horizontal and vertical directions for adjustment and electronic scanning. The metasurface coded antenna element includes: A transmissive metasurface coded array antenna has a receiving end, an output end, and a control end. The receiving end of the transmissive metasurface coded array antenna serves as the receiving end of a metasurface coded antenna element, and the output end of the transmissive metasurface coded array antenna serves as the output end of a metasurface coded antenna element. A voltage control module has an input terminal and an output terminal, wherein the output terminal of the voltage control module is coupled to the control terminal of the transmissive metasurface coded array antenna; The encoding control module has an input terminal and an output terminal. The input terminal of the encoding control module is connected to a computer to receive the beam scanning angle command, and the output terminal of the encoding control module is coupled to the input terminal of the voltage control module. The encoding control module controls the output voltage of the voltage control module according to the received beam scanning angle command, thereby realizing the adjustment and electrical scanning of the beam pointing of the transmissive metasurface encoded array antenna in the horizontal and vertical directions. The radiometer receiving channel includes: A radio frequency amplifier, coupled to the output of the transmissive metasurface coded array antenna, is used to amplify the millimeter-wave signal received by the antenna. A square-law detector, connected to the radio frequency amplifier, is used to convert the amplified millimeter-wave signal into a DC signal; A low-pass filter, connected to the square-law detector, is used to filter out high-frequency noise in the output signal of the square-law detector. An integrator, connected to the low-pass filter, is used to integrate the signal output by the low-pass filter to obtain the radiated power signal. During the beam scanning of the target scene, when the beam of the transmissive metasurface coded array antenna is tuned to a specified angle, the coding control module will send a signal to the computer that the beam has been tuned. At this time, the computer will control the AD acquisition unit to collect and store the radiation power signal output by the radiometer receiving channel.

2. The electrically scanned radiometer device based on a metasurface coded antenna according to claim 1, characterized in that, Also includes: An image display unit, connected to the computer, is used to display the imaging processing results.

3. The electrically scanned radiometer device based on a metasurface coded antenna according to claim 1, characterized in that, The radio frequency amplifier is a low-noise amplifier with a noise figure of less than 4dB and a gain of more than 20dB.

4. The electrically scanned radiometer device based on a metasurface coded antenna according to claim 1, characterized in that, The square-law detector uses a Schottky diode.

5. The electrically scanned radiometer device based on a metasurface coded antenna according to claim 1, characterized in that, The low-pass filter has a cutoff frequency of 1MHz and an out-of-band rejection greater than 30dB.

6. The electrically scanned radiometer device based on a metasurface coded antenna according to claim 1, characterized in that, The integration time of the integrator is adjustable, ranging from 1 μs to 20 μs.

7. The electrically scanned radiometer device based on a metasurface coded antenna according to claim 1, characterized in that, The encoding control module is implemented using a field-programmable gate array (FPGA).

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