Large parabolic antenna surface shape precision measurement and phase compensation system based on metasurface

Abstract

The invention, which relates to the technical field of radio astronomy, provides a metasurface-based large-scale parabolic antenna surface shape precision measurement and phase compensation system comprising an antenna module, a metasurface module and a data processing module. The antenna module is used for transmitting the received electromagnetic beam to the metasurface module; the metasurface module is used for receiving the target voltage information transmitted by the data processing module and adjusting the phase of the electromagnetic beam according to the target voltage information, and the target voltage information is obtained by converting compensation phase information corresponding to the power information of the electromagnetic beam by the data processing module. According to the system, high-precision and rapid surface shape precision measurement can be realized, and rapid surface shape compensation is also realized.

Description

Technical Field

[0001] This invention relates to the field of radio astronomy, specifically to a system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface. Background Technology

[0002] With the development of radio astronomy, large parabolic antennas are widely used in lunar-Earth communication, deep space exploration, and other fields. This has placed higher demands on the efficiency and directivity of these antennas. Large parabolic antennas are susceptible to influences from factors including their own weight, solar radiation temperature, and environmental wind loads, leading to a discrepancy between the actual and ideal surface shape of the antenna reflector. The magnitude of this discrepancy is measured by surface shape accuracy. Surface shape accuracy determines the antenna efficiency and the highest operating frequency. Therefore, it is necessary to measure the surface shape and adjust the reflector panel's orientation based on the measurement results to improve surface shape accuracy, thereby meeting the antenna efficiency and frequency requirements.

[0003] There are three main factors affecting antenna surface shape accuracy: gravity, solar radiation, and wind load. Among these, the antenna's own gravity is a steady-state factor; the surface shape accuracy under gravity is only related to the antenna's elevation angle. On windless nights, photogrammetry, microwave holography, laser scanning, or wavefront perturbation methods can be used to obtain the surface shape accuracy at different elevation angles from 0 to 90°, thereby constructing a deformation model of the reflector surface under the influence of gravity. However, for antenna surface shape accuracy affected by non-steady-state environmental factors such as solar radiation temperature and wind load, traditional photogrammetry, microwave holography, and wavefront perturbation methods are time-consuming, and the measurement speed cannot keep up with the rate of change in surface shape accuracy. Therefore, it is difficult to construct a deformation model of the reflector surface under the influence of solar radiation temperature and environmental wind load. To address the need for rapid measurement of antenna surface shape accuracy under the influence of solar radiation temperature and wind load, this technical field is researching and applying methods such as laser scanning, multi-camera photogrammetry, and microwave holography based on phased array feeds.

[0004] Laser scanning utilizes a laser scanner to emit a laser beam to scan the reflective surface of an antenna, and obtains surface shape data by receiving the reflected signals to calculate accuracy. This method has drawbacks: measurement error increases with scanning distance, and the accuracy of surface shape measurement is significantly affected by factors such as rain, fog, and haze.

[0005] Traditional photogrammetry involves capturing images of target points on the antenna reflector surface using a camera, then calculating the three-dimensional coordinates of these points using photogrammetric algorithms to assess surface accuracy. This method can significantly improve measurement speed by employing multi-camera photogrammetry. However, it is also limited by the ranging accuracy of the cameras and is greatly affected by rain, fog, and haze. Furthermore, because the cameras need to be mounted on the edge of the reflector surface or on support legs, this method is also constrained by the spatial dimensions of the telescope structure, including the reflector surface and support legs, as well as the stability of these structures under environmental wind loads.

[0006] Traditional microwave holography measures the far-field of the antenna and performs a two-dimensional Fourier transform to obtain the aperture field. The surface shape accuracy is then calculated based on the quantitative relationship between the aperture field phase distribution and the reflector surface shape variation. This process requires scanning the antenna's far-field, making it time-consuming. Microwave holography based on a phased array feed can instantaneously obtain focal plane field information, enabling rapid measurement of surface shape accuracy. This method achieves comparable measurement accuracy to traditional microwave holography and is more suitable for fixed-focus antennas. However, this phased array feed-based method suffers from in-array interference within the feed element and exhibits larger measurement errors for antennas with relatively small focal diameters. Summary of the Invention

[0007] This invention provides a system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface, comprising an antenna module, a metasurface module, and a data processing module. The antenna module transmits the received electromagnetic beam into the metasurface module. The metasurface module receives the target voltage information transmitted by the data processing module and adjusts the phase of the electromagnetic beam according to the target voltage information, wherein the target voltage information is obtained by the data processing module through conversion of the compensation phase information corresponding to the power information of the electromagnetic beam.

[0008] In the above scheme, the antenna module includes a parabolic antenna and a beam waveguide. The parabolic antenna includes a parabolic primary reflector and a parabolic secondary reflector. The parabolic secondary reflector is located at the focal point of the parabolic primary reflector. The parabolic primary reflector is used to focus the received electromagnetic beam onto the parabolic secondary reflector. The parabolic secondary reflector is used to transmit the electromagnetic beam to the metasurface module through the beam waveguide.

[0009] In the above scheme, the antenna module also includes a feed parabolic surface, a feed antenna, and a power meter. The feed antenna and the power meter are connected by a feed cable. The feed parabolic surface is used to receive the electromagnetic beam emitted by the metasurface module and reflected by multiple planar mirrors, and transmits the electromagnetic beam to the feed antenna. The feed antenna is used to transmit the received electromagnetic beam to the power meter. The power meter is used to convert the received electromagnetic beam into an electrical signal and display the power information.

[0010] In the above scheme, the metasurface module includes a metasurface array and a power supply control submodule, which are connected by a power supply cable. The metasurface array is used to reflect the electromagnetic beam received from the parabolic sub-reflector to the feed parabolic surface through multiple planar mirrors. The metasurface array is used to receive the control DC voltage transmitted by the power supply control submodule through the power supply cable.

[0011] In the above scheme, the metasurface array includes multiple metasurface units, and the feed cables include multiple feed cables, with each pair of feed cables corresponding to one metasurface unit; after receiving the control DC voltage transmitted by the feed control submodule, the multiple metasurface units perform instantaneous phase adjustment on the received electromagnetic beam and reflect the phase-modulated electromagnetic beam.

[0012] In the above scheme, the power supply control submodule is used to convert the target voltage information received from the data processing module into a fixed control DC voltage.

[0013] In the above scheme, the data processing module includes a microprocessor and a computing device. The power meter, microprocessor, and computing device are connected in sequence via a power supply cable. The microprocessor is connected to the power supply control submodule via the power supply cable. The microprocessor is used to receive power information sent by the power meter and send the generated initial voltage information and power information to the computing device. The computing device is used to generate compensation phase information based on the initial voltage information and power information and feed it back to the microprocessor.

[0014] In the above scheme, the microprocessor is used to convert the compensation phase information into target voltage information and transmit it to the power supply control submodule via the power supply cable.

[0015] In the above scheme, the computing device is used to adjust the compensation phase information when it determines that the power value in the power information is less than a preset threshold.

[0016] In the above scheme, the computing device is also used to calculate and display the surface accuracy value and compensation phase information based on the initial voltage information and power information.

[0017] The technical solutions of the embodiments of the present invention have at least the following beneficial effects:

[0018] (1) This system can quickly and accurately obtain antenna surface parameters, which is an effective solution to improve antenna efficiency. It overcomes the problems of reduced accuracy due to ambient light and rain / snow interference, long measurement time, and inability to compensate for power in the current mainstream antenna surface measurement methods.

[0019] (2) This system changes the optical path by setting metasurface elements to alter the phase, effectively adding a Zernike polynomial deformation to the antenna based on the original deformation. This achieves the same effect as wavefront perturbation achieved by Zernike polynomial deformation, which is orthogonal to the main surface loading. This avoids the waiting time of the actuator and achieves high measurement accuracy. Furthermore, since the metasurface elements can actively change the phase of the wave in the middle of the wave path, the phase distribution that needs to be supplemented can be deduced from the Zernike polynomial result, thereby achieving surface shape compensation and improving antenna efficiency.

[0020] (3) The system can achieve high precision and fast surface shape accuracy measurement, while also realizing fast surface shape compensation. It is a technical solution that integrates surface shape accuracy measurement and surface shape compensation, providing a high-quality and high-efficiency surface shape error elimination method for large parabolic antenna panels. Attached Figure Description

[0021] Figure 1 The schematic diagram illustrates a structural block diagram of a large parabolic antenna surface shape accuracy measurement and phase compensation system based on metasurface according to an embodiment of the present invention;

[0022] Figure 2 The diagram schematically shows a front view of a large beam waveguide parabolic antenna containing a metasurface, assuming electromagnetic wave incidence according to an embodiment of the present invention.

[0023] Figure 3 A schematic side view of a large beam waveguide parabolic antenna containing a metasurface, assuming electromagnetic wave incident according to an embodiment of the present invention, is shown.

[0024] Figure 4 The illustration schematically shows a global view of a large beam waveguide parabolic antenna containing a metasurface, with electromagnetic waves incident on it according to an embodiment of the present invention.

[0025] Figure 5 A schematic diagram of the coordinate system of the parabolic principal reflecting surface according to an embodiment of the present invention is shown.

[0026] Figure 6 A flowchart illustrating the determination of orthogonal basis functions or Zernike polynomials according to an embodiment of the present invention is shown schematically.

[0027] Figure 7 A flowchart illustrating the algorithm for calculating surface shape error and phase compensation value according to an embodiment of the present invention is shown.

[0028] Figure 8 A schematic diagram of the aperture surface wavefront of the parabolic primary reflector according to an embodiment of the present invention is shown.

[0029] Figure 9 A schematic diagram illustrating the received power of a parabolic antenna according to an embodiment of the present invention is shown. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0031] Figure 1 The diagram schematically illustrates a structural block diagram of a large parabolic antenna surface shape accuracy measurement and phase compensation system based on a metasurface according to an embodiment of the present invention. Figure 2The diagram schematically shows a front view of a large beam waveguide parabolic antenna containing a metasurface, assuming electromagnetic wave incidence according to an embodiment of the present invention. Figure 3 A schematic side view of a large beam waveguide parabolic antenna containing a metasurface, assuming electromagnetic wave incidence according to an embodiment of the present invention, is shown. Figure 4 The illustration schematically shows a global view of a large beam waveguide parabolic antenna containing a metasurface, with electromagnetic waves incident on it according to an embodiment of the present invention.

[0032] Please refer to the following for details. Figure 1 The system includes an antenna module 1, a metasurface module 2, and a data processing module 3. In an embodiment of the present invention, the antenna module 1 is used to transmit the received electromagnetic beam into the metasurface module 2; the metasurface module 2 is used to receive the target voltage information transmitted by the data processing module 3, and to adjust the phase of the electromagnetic beam according to the target voltage information, wherein the target voltage information is obtained by the data processing module 3 by converting the compensated phase information corresponding to the power information of the electromagnetic beam.

[0033] like Figure 1 As shown, antenna module 1 includes a parabolic antenna 15 and a beam waveguide 4. The parabolic antenna 15 includes a parabolic primary reflector 5 and a parabolic secondary reflector 6, with the secondary reflector 6 located at the focal point of the primary reflector 5. The primary reflector 5 focuses the received electromagnetic beam onto the secondary reflector 6, while the secondary reflector 6 transmits the electromagnetic beam through the beam waveguide 4 into the metasurface module 2.

[0034] Furthermore, such as Figure 1 As shown, antenna module 1 also includes a parabolic feed surface 14, a feed antenna 7, and a power meter 8. The feed antenna 7 and the power meter 8 are connected by a feed cable. The parabolic feed surface 14 receives the electromagnetic beam emitted by the metasurface module 2 and reflected by multiple planar mirrors, and transmits the electromagnetic beam to the feed antenna 7. The feed antenna 7 transmits the received electromagnetic beam to the power meter 8. The power meter 8 converts the received electromagnetic beam into an electrical signal and displays power information.

[0035] For example, the parabolic antenna 15 can be a front-fed parabolic antenna, a rear-fed parabolic antenna, or an offset-fed parabolic antenna, etc. The parabolic antenna 15 focuses electromagnetic waves to the focal point of the parabola.

[0036] For example, the beam waveguide 4 section is a device that converts the electromagnetic waves collected by the main reflector of the parabolic antenna into plane waves for transmission. The beam waveguide section places a beam waveguide mirror at the focal point of the parabolic surface to convert the electromagnetic waves into plane waves for transmission to the metasurface section. After passing through the metasurface section, the plane waves, in the form of plane waves, pass through multiple plane reflectors and then enter the feed antenna.

[0037] For example, the feed antenna 7 is used to receive and transmit processed electromagnetic waves and convert the electromagnetic waves into electrical signals. The feed antenna 7 can be a phased array or a horn antenna.

[0038] For example, the power meter 8 is a device used to measure and display the power of electromagnetic wave energy received by the feed antenna.

[0039] Based on the above, please combine Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, when electromagnetic waves are incident on antenna module 1, X1 and X2 are two axially incident electromagnetic waves (here, axial incident means the incident direction is perpendicular to the aperture surface of the parabolic main reflector 5). These two electromagnetic waves converge at focal point 17 after being reflected by the parabolic main reflector 5, parabolic sub-reflector 6, metasurface module 2, first plane mirror 12, second plane mirror 16, and feed parabolic surface 14. The reflection points of the electromagnetic waves on the parabolic main reflector 5, parabolic sub-reflector 6, metasurface module 2, first plane mirror 12, second plane mirror 16, and feed parabolic surface 14 can be denoted as P3, P4, P5, P6, P7, and P8, which correspond one-to-one with each other. The phase center of the feed receiving the electromagnetic waves coincides with focal point 17.

[0040] Furthermore, when the antenna module 1 transmits electromagnetic waves, the electromagnetic waves are emitted from the focal point 17 and reflected by the feed parabolic surface 14, the second plane reflector 16, the first plane reflector 12, the metasurface module 2, the parabolic sub-reflector 6, and the parabolic main reflector 5, pointing towards the target sky region.

[0041] Understandably, when the parabolic principal reflector 5 is not deformed, the electromagnetic wave beams X1 and X2 travel the same distance from the focal point 17 to the aperture of the parabolic principal reflector 5. Therefore, upon reaching the aperture of the parabolic principal reflector 5, the wavefront of the electromagnetic wave is an equiphase surface. When the parabolic principal reflector 5 is deformed, the electromagnetic wave beams X1 and X2 travel different distances, and the wavefront of the electromagnetic wave is distorted.

[0042] For example, assuming that the parabolic primary reflector 5 is deformed only at a certain point P3, then by compensating for the deformation at the corresponding position on the electromagnetic wave propagation path (e.g., P3, or the corresponding point P4 on the parabolic secondary reflector 6, or the corresponding point P5 on the metasurface module 2, or the corresponding point P6 on the first plane mirror 12, or the corresponding point P7 on the second plane mirror 16, or the corresponding point P8 on the feed parabolic surface 14), the aperture surface wavefront of the parabolic primary reflector 5 can be restored to an equiphase surface.

[0043] To compensate for deformation, the traditional method involves installing actuators behind the parabolic main reflector frame; around 2000 actuators can be installed for a 100-meter antenna. Alternatively, actuators can be installed behind the plane mirror frame; plane mirrors are generally less than ten meters in size, allowing for around 100 actuators. The disadvantages of the traditional method are that the actuator assembly is heavy, significantly increasing the overall weight of the antenna module and limiting the number of actuators that can be installed. The limited number of actuators restricts the number of control points needed to generate target disturbances during surface shape error measurement, thus leading to lower measurement accuracy.

[0044] In an embodiment of the present invention, a metasurface module is proposed to electronically and rapidly adjust the reflection phase by replacing the actuator on the back frame of the parabolic primary reflector with a metasurface.

[0045] The following describes in detail the metasurface module, the data processing module, and the process by which the metasurface module adjusts the electromagnetic beam phase based on the target voltage information provided by the data processing module.

[0046] like Figure 1 As shown, in an embodiment of the present invention, the metasurface module 2 includes a metasurface array 11 and a power supply control submodule 13, which are connected by a power supply cable. The metasurface array 11 is used to reflect the electromagnetic beam received from the parabolic sub-reflector 6 through multiple planar mirrors to the feed parabolic surface 14; the metasurface array 11 is used to receive the control DC voltage transmitted by the power supply control submodule 13 via the power supply cable.

[0047] Furthermore, such as Figure 1 As shown, the metasurface array 11 includes multiple metasurface units 111, and multiple feed cables are included, with each pair of feed cables corresponding to one metasurface unit 111. After receiving the control DC voltage transmitted by the feed control submodule 13, the multiple metasurface units 111 perform instantaneous phase adjustment on the received electromagnetic beam and reflect the phase-modulated electromagnetic beam.

[0048] For example, the metasurface array 11 can be a reflective metasurface array or a transmissive metasurface array. The phase change units on the metasurface unit 111 can be devices such as microelectromechanical systems, varactor diodes, varactor tubes, or diodes that change their impedance values ​​through voltage.

[0049] In an embodiment of the present invention, the power supply control submodule 13 is used to convert the target voltage information received from the data processing module 3 into a fixed control DC voltage.

[0050] For example, the power supply control submodule 13 controls the phase of the metasurface unit with a DC voltage. The power supply control submodule 13 consists of two parts: a power supply cable and a control board. The power supply cable is used to apply a DC voltage to the phase change unit on the metasurface unit, thereby controlling the degree of phase change. The control board is used to receive the target voltage information from the data processing module 3 and convert it into a DC voltage to power the metasurface unit.

[0051] For example, the power supply control submodule 13 can typically be a hardware integrated circuit board built from independent components, amplifiers, and MCUs.

[0052] Please continue reading. Figure 1 The data processing module 3 includes a microprocessor 9 and a computing device 10. The power meter 8, the microprocessor 9 and the computing device 10 are connected in sequence via a power supply cable. The microprocessor 9 is connected to the power supply control submodule 13 via a power supply cable.

[0053] In an embodiment of the present invention, the microprocessor 9 is used to receive power information sent by the power meter 8, and send the generated initial voltage information and power information to the computing device 10. The computing device 10 is used to generate compensation phase information based on the initial voltage information and power information and feed it back to the microprocessor 9.

[0054] Understandably, the microprocessor 9 processes the power meter's power data and outputs the initial voltage value, thus achieving the digital-to-analog conversion function.

[0055] In an embodiment of the present invention, the computing device 10 is used to adjust the compensation phase information when it is determined that the power value in the power information is less than a preset threshold.

[0056] Understandably, the computing device 10 calculates and displays the surface accuracy value and compensated phase information based on the initial voltage and power information. For example, the compensated phase information can be determined by comparing whether the power is at its maximum value. Furthermore, the computing device 10 feeds the compensated phase information back to the microprocessor 9. Finally, the microprocessor 9 converts the compensated phase information into target voltage information and transmits it to the power supply control submodule 13 via the power supply cable.

[0057] Based on the above, it can be understood that the parabolic main reflector 5 of the parabolic antenna focuses the received electromagnetic waves onto the parabolic sub-reflector 6. The parabolic sub-reflector 6 transmits the electromagnetic waves as parallel waves through the beam waveguide 4 to the metasurface array 11. The metasurface array 11 changes the phase of the signal in the electromagnetic waves and transmits them to the feed parabolic surface 14 through multiple second plane mirrors 16. The feed parabolic surface 14 focuses the electromagnetic waves into the feed antenna 7. The feed antenna 7 converts the electromagnetic waves into electrical signals, which are displayed and measured by the power meter 8. The power meter 8 sends the power information to the microprocessor 9. The microprocessor 9 receives the power information sent by the power meter 8 and sends the generated initial voltage information and power information to the computing device 10. The computing device 10 generates compensation phase information based on the initial voltage information and power information and feeds it back to the microprocessor 9. The microprocessor 9 converts the compensation phase information into target voltage information and transmits it to the feed control submodule 13 through the feed cable. Finally, the power supply control submodule 13 converts the target voltage information into a fixed control DC voltage, and controls the phase value of the metasurface unit to change the phase of the electromagnetic wave in the form of DC voltage.

[0058] It is also understandable that the computing device 10 continuously adjusts the phase information through algorithms, thereby causing the phase of the electromagnetic wave to change continuously, ultimately causing the power displayed by the power meter 8 to reach its maximum value.

[0059] Through embodiments of the present invention, a metasurface module and a data processing module are proposed. By replacing the actuator on the back frame of the parabolic primary reflector with a metasurface, the reflection phase can be adjusted electronically and quickly. This not only significantly shortens the measurement time of the wavefront perturbation method and achieves higher measurement accuracy, but also improves antenna efficiency by changing the phase distribution to compensate for the deformation of the reflector.

[0060] The following is a detailed description of the principle of using metasurfaces to achieve accurate measurement of the surface shape and phase compensation of large parabolic antennas.

[0061] Figure 5 A schematic diagram of the coordinate system of the parabolic principal reflecting surface according to an embodiment of the present invention is shown. Figure 6 A flowchart illustrating the determination of orthogonal basis functions or Zernike polynomials according to an embodiment of the present invention is shown. Figure 7 A flowchart illustrating the algorithm for calculating the polar phase compensation value of surface shape error according to an embodiment of the present invention is shown. Figure 8 A schematic diagram of the aperture surface wavefront of the parabolic primary reflector according to an embodiment of the present invention is shown. Figure 9 A schematic diagram illustrating the received power of a parabolic antenna according to an embodiment of the present invention is shown.

[0062] Understandably, if metasurfaces are used, tens of thousands of metasurface elements can be arranged within a range of ten meters. Many of these metasurface elements are lightweight and can be used to adjust the reflection phase. The specific number of arrangeable metasurface elements can be roughly estimated as follows: the shortest operating wavelength of the antenna is λ, and the size of the metasurface element is the sub-operating wavelength. Therefore, if the area of ​​the original plane mirror with the actuator is A, then the number of metasurface elements > A / λ. 2 With a minimum operating wavelength of 10mm and a reflective area of ​​9πm², it can achieve this. 2 For example, theoretically more than 200,000 metasurface units can be arranged.

[0063] Please combine Figure 2 and Figure 5 As shown, taking the ideal condition (i.e., when the parabolic primary reflector is not deformed), the geometric center O of the aperture surface (the edge of which is a circle) of the parabolic primary reflector 5 is taken as the origin. The axis passing through the origin O and perpendicular to the aperture surface of the parabolic primary reflector 5 is taken as the Z-axis, with the positive direction of the Z-axis pointing from the antenna to the sky. An arbitrary ray originating from the origin O and pointing towards the edge of the aperture of the parabolic primary reflector 5 is taken as the X-axis. The Y-axis is determined according to the right-hand screw rule, as shown in the figure. The positive direction of the Y-axis is indicated by pointing from outside the paper to inside the paper, while the direction from inside the paper to outside the paper is usually indicated by... express.

[0064] Due to the influence of gravity, sunlight, wind, and other factors, the parabolic principal reflector 5 deforms. Before deformation, in the aforementioned coordinate system, the surface shape of the parabolic principal reflector 5 can be represented by z1(x,y); after deformation, the surface shape of the parabolic principal reflector 5 can be represented by z2(x,y); therefore, the surface shape error distribution of the parabolic principal reflector 5 is δ(x,y) = z2(x,y) - z1(x,y). Representing x and y in polar coordinates (ρ,θ), the surface shape error distribution of the parabolic principal reflector 5 becomes... ρ is the polar radius, θ is the polar angle; x = ρcosθ, y = ρsinθ.

[0065] here It can be achieved through a series of mutually orthogonal basis functions. To indicate, that is (1)

[0066] Among them, a n is the weighting coefficient of the orthogonal basis functions, the integration region S is the entire parabolic principal reflector 5, and N is the total number of orthogonal basis functions used. In the above equation (1), the first expression represents the surface shape error of the parabolic principal reflector 5 as the sum of N orthogonal basis functions; the second expression defines the pairwise orthogonality of the basis functions. Orthogonal basis function f nThe specific expression for (ρ,θ) is not unique. One type of orthogonal basis function that meets the practical needs of reflector antenna engineering is the Zernike polynomial, which can be expressed as:

[0067] (2)

[0068] Where k is the order of the polynomial, and its value ranges from 0 to positive integers; l is the frequency, l = k-2m, k and l have the same parity, and k ≥ | l |.

[0069] For example, when k=0 and l=0, the orthogonal basis function f n (ρ,θ) or Zernike polynomial The specific expression is 1;

[0070] When k=1 and l=-1, the orthogonal basis function f n (ρ,θ) or Zernike polynomial The specific expression is ρsinθ;

[0071] When k=1 and l=1, the orthogonal basis function f n (ρ,θ) or Zernike polynomial The specific expression is ρcosθ;

[0072] When k=2 and l=-2, the orthogonal basis function f n (ρ,θ) or Zernike polynomial The specific expression is ρ 2 sin(2θ);

[0073] When k=2 and l=0, the orthogonal basis function f n (ρ,θ) or Zernike polynomial The specific expression is 2ρ 2 -1;

[0074] When k=2 and l=2, the orthogonal basis function f n (ρ,θ) or Zernike polynomial The specific expression is ρ 2 cos(2θ);

[0075] If the sum of the above six orthogonal basis functions is used to represent the surface shape error distribution of the parabolic principal reflector 5, then the total number of orthogonal basis functions used is N=6. Since these six orthogonal basis functions have been determined, when representing the surface shape error, it is only necessary to solve for the coefficients a1, a2, a3, a4, a5, and a6 before each orthogonal basis function. Figure 6 As shown, in order to f n (ρ,θ) and In a one-to-one correspondence, let N = [max(k) + 1][max(k) + 2] / 2; where max(k) represents the maximum value of k. k starts from 0 and increments by 1; l starts from -k and increments by 2 until l = k; n starts from 1, and for each pair (k, l, n) formed, the value of n is incremented by 1 until n = N.

[0076] Specifically, please combine Figure 7 As shown in the algorithm flowchart, from the perspective of antenna transmission mode, the metasurface part is used to effectively add a Zernike polynomial deformation to the main reflector on the basis of the original deformation. By altering the optical path, the aperture surface wavefront can be disturbed. The resulting perturbation leads to an error in the principal reflecting surface shape. It can be represented as

[0077] (3)

[0078] In the formula, the orthogonal basis functions (which are also Zernike polynomials) f i (ρ,θ) are known quantities, γ i It is the disturbance coefficient.

[0079] The perturbation coefficient can be positive or negative, and it increases from its minimum value to its maximum value, with an increment step size dγ. i The parameters can be quickly set using the corresponding voltage or current parameters. The minimum value can be -λ, and the maximum value can be λ. Generally, the smaller the step size of the perturbation coefficient increase, the better the accuracy of the measured surface shape. Compared to actuators that modify the step size mechanically, metasurfaces can modify the step size at smaller intervals and at a faster speed using electronic adjustment.

[0080] like Figure 8 As shown, when the orthogonal basis functions f i The perturbation coefficient γ of (ρ, θ) i = -a i At this point, the antenna surface accuracy (i.e., the root mean square error RMS) reaches its minimum. According to the Ruze formula (here, the Ruze formula is used in antenna engineering to describe the influence of random errors on the surface of a parabolic antenna on the antenna gain), the antenna gain or power G(γ) at this time is minimized. i () Reaching its maximum, such as the antenna's received power Figure 9 As shown, the expression is:

[0081] (4)

[0082] Where G0 is the antenna gain or power when the reflector is undeformed, and λ is the operating wavelength for surface shape measurement.

[0083] Based on the above, it can be understood that by measuring the changes in antenna gain or power under different amplitude disturbances, the gain (power) disturbance coefficient curve G(γ) can be solved. i The maximum value of ) can be used to obtain the weighting coefficients a before each Zernike polynomial. n Thus, the surface shape error distribution of the main reflecting surface is obtained. Surface shape accuracy (RMS) and compensation phase value.

[0084] Through embodiments of the present invention, metasurface elements can be used to alter the optical path by adding a Zernike polynomial deformation to the antenna based on its original deformation, thereby achieving the same effect as wavefront perturbation achieved by Zernike polynomial deformation orthogonal to the main surface loading. This avoids the actuator's waiting time for loading and achieves high measurement accuracy. Since the metasurface element can actively change the wave phase in the middle of the wavepath, the required phase distribution can be inferred from the Zernike polynomial result, thus achieving surface shape compensation and improving antenna efficiency.

[0085] Through the embodiments of the present invention, the system can achieve high precision and rapid measurement of surface shape accuracy, while also realizing rapid surface shape compensation. It is a technical solution that integrates surface shape accuracy measurement and surface shape compensation, providing a high-quality and high-efficiency method for eliminating surface shape errors for large parabolic antenna panels.

[0086] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0087] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0088] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface, characterized in that, It includes an antenna module (1), a metasurface module (2), and a data processing module (3); The antenna module (1) is used to transmit the received electromagnetic beam into the metasurface module (2); The metasurface module (2) is used to receive the target voltage information transmitted by the data processing module (3) and adjust the phase of the electromagnetic beam according to the target voltage information, wherein the target voltage information is obtained by the data processing module (3) based on the compensation phase information corresponding to the power information of the electromagnetic beam.

2. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 1, characterized in that, The antenna module (1) includes a parabolic antenna (15) and a beam waveguide (4). The parabolic antenna (15) includes a parabolic primary reflector (5) and a parabolic secondary reflector (6). The parabolic secondary reflector (6) is located at the focal point of the parabolic primary reflector (5). The parabolic primary reflector (5) is used to focus the received electromagnetic beam onto the parabolic secondary reflector (6). The parabolic sub-reflector (6) is used to transmit the electromagnetic beam through the beam waveguide (4) into the metasurface module (2).

3. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 2, characterized in that, The antenna module (1) further includes a feed parabolic surface (14), a feed antenna (7), and a power meter (8), wherein the feed antenna (7) and the power meter (8) are connected by a feed cable; The feed parabolic surface (14) is used to receive the electromagnetic beam emitted by the metasurface module (2) and reflected by multiple planar mirrors, and to transmit the electromagnetic beam to the feed antenna (7). The feed antenna (7) is used to transmit the received electromagnetic beam to the power meter (8). The power meter (8) is used to convert the received electromagnetic beam into an electrical signal and display power information.

4. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 2, characterized in that, The metasurface module (2) includes a metasurface array (11) and a power supply control submodule (13), which are connected by a power supply cable. The metasurface array (11) is used to reflect the electromagnetic beam received from the parabolic sub-reflector (6) to the feed parabolic surface (14) through multiple planar mirrors. The metasurface array (11) is used to receive the control DC voltage transmitted by the power supply control submodule (13) via the power supply cable.

5. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 4, characterized in that, The metasurface array (11) includes multiple metasurface units (111), and the feed cables include multiple feed cables, with each pair of feed cables corresponding to one metasurface unit (111). After receiving the control DC voltage transmitted by the power supply control submodule (13), the multiple metasurface units (111) perform instantaneous phase adjustment on the received electromagnetic beam and reflect the phase-modulated electromagnetic beam.

6. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 4, characterized in that, The power supply control submodule (13) is used to convert the target voltage information received from the data processing module (3) into a fixed control DC voltage.

7. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 4, characterized in that, The data processing module (3) includes a microprocessor (9) and a computing device (10). The power meter (8), the microprocessor (9) and the computing device (10) are connected in sequence via a power supply cable. The microprocessor (9) is connected to the power supply control submodule (13) via a power supply cable. The microprocessor (9) is used to receive power information sent by the power meter (8) and send the generated initial voltage information and the power information to the computing device (10). The computing device (10) is used to generate compensation phase information based on the initial voltage information and power information and feed it back to the microprocessor (9).

8. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 7, characterized in that, The microprocessor (9) is used to convert the compensation phase information into target voltage information and transmit it to the power supply control submodule (13) via the power supply cable.

9. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 7, characterized in that, The computing device (10) is used to adjust the compensation phase information when it is determined that the power value in the power information is less than a preset threshold.

10. The system for measuring the surface shape accuracy and phase compensation of a large parabolic antenna based on a metasurface according to claim 7, characterized in that, The computing device (10) is also used to calculate and display the surface accuracy value and compensation phase information based on the initial voltage information and power information.

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