High-temperature ablation radome electrical performance compensation method based on array element phase adjustment

Abstract

The invention discloses a high-temperature ablation radome electrical performance compensation method based on array element phase adjustment, and the method comprises the steps: reconstructing a part of the radome, the temperature of which exceeds the ablation temperature, into an air cover when a finite element model of the high-temperature ablation radome is established based on the temperature distribution of the radome in a working environment and the data of the material attribute changing along with the temperature; therefore, the finite element model of the high-temperature ablation antenna housing is obtained. Full-wave calculation is carried out by using COMLOL to obtain the electrical performance of the array antenna loaded with the high-temperature ablation radome, and the optimal phase distribution of the array antenna in the radome is iteratively solved based on a particle swarm optimization algorithm, so that the influence of high-temperature ablation on the electrical performance of the radome is compensated. The influence of high-temperature ablation on the electrical performance of the antenna housing can be considered while the compensation precision is ensured, and the method has relatively high compensation effect and precision and is wide in applicability.

Description

Technical Field

[0001] The invention belongs to the technical field of radar antennas, and in particular relates to a method for compensating electrical performance of a high-temperature ablation antenna cover based on array element phase adjustment. Background Art

[0002] Aircraft radomes are mainly used to protect the electronic equipment inside them and prevent them from being damaged by rain, snow, wind load, lightning strikes and other flight conditions. In order to meet aerodynamic requirements, aircraft radomes are generally designed to be streamlined. This structure has a significant impact on the electrical performance of the electronic equipment inside the radome, but through excellent structural design, its electrical performance can meet the working requirements.

[0003] During the service of the aircraft, there is a severe aerodynamic heating phenomenon, which causes the temperature of the radome at the front end of the aircraft to rise sharply. When the temperature exceeds a certain limit, the radome will also burn, which will cause the material parameters and structure of the radome to change, causing good or bad effects on the electrical performance. Since it is difficult to compensate for the change in electrical performance by adjusting the structure of the radome during service, the method of adjusting the excitation phase of the antenna inside the radome is generally used to compensate for the electrical performance. This requires that a pre-adjustment plan for the phase distribution of the antenna inside the radome under various flight conditions be prepared in the early design stage of the radome, so as to improve the electrical performance of the aircraft radome during service.

[0004] At present, the research results on the influence of high-temperature ablation of antenna covers on electrical performance are different. CN111539141A discloses a method for rapid compensation of electrical performance of active phased array antennas under high-temperature ablation. The method regards electromagnetic waves as a ray emitted from the antenna radiation source point based on the geometric optics method, and then calculates the changes in amplitude and phase of the electromagnetic waves after passing through the high-temperature ablated antenna cover according to the equivalent transmission line theory, and then compensates the phase of the antenna according to the changes. Although this geometric optics compensation method based on high-frequency approximation has a fast calculation speed, it is difficult to ensure the accuracy of the calculation. The paper "Rapid Optimization of Antenna Cover Aiming Error Based on Array Element Phase Control" proposed by Wang Wei in 2015 discloses a method for rapid optimization of aiming error of antenna with cover by adjusting the excitation phase of phased array unit. Based on the particle swarm algorithm, the adjustment optimization of continuous variable phase and digital discrete phase is realized. However, when the antenna cover is heated at high temperature, the dielectric constant and loss tangent of the material will change with temperature, so that its electrical performance is difficult to guarantee. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a method for compensating the electrical performance of a high-temperature ablation antenna cover based on array element phase adjustment. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] The present invention provides a method for compensating electrical performance of a high-temperature ablation radome based on array element phase adjustment, the method comprising:

[0007] S1: Determine the structural parameters and material properties of the aircraft radome;

[0008] S2: determining the flight condition of the radome of the aircraft according to the flight curve of the aircraft;

[0009] S3: using commercial software Fluent, according to the structural parameters and flight conditions, a fluid calculation grid model of the flow field and the radome of the aircraft is established, thereby obtaining temperature distribution data of the outer surface of the radome;

[0010] S4: The temperature distribution data and material property data of the outer surface of the radome are imported into the commercial software COMLOL in the form of interpolation functions to construct a finite element model of the high-temperature ablation radome;

[0011] S5: using MATLAB, based on particle swarm optimization parameters, randomly generating the phase distribution of the antenna array in the radome, and specifying the scanning angle of the antenna array; the particle swarm optimization parameters include: the number of individuals in the optimization population and the maximum number of iterations;

[0012] S6: using commercial software COMLOL, based on the phase distribution and the scanning angle, obtaining a first far-field pattern of the array antenna, and extracting electrical performance of the array antenna from the first far-field pattern;

[0013] S7: using the commercial software COMLOL, based on the finite element model, phase distribution and scanning angle of the high temperature ablation radome, obtaining a second far-field pattern of the array antenna after the high temperature ablation radome is loaded, thereby determining the electrical performance of the array antenna after the high temperature ablation radome is loaded;

[0014] S8: establishing an optimization design model based on the phase distribution of the antenna array and the electrical performance of the array antenna after loading the high-temperature ablation radome; using the particle swarm optimization algorithm in MATLAB, iterating the optimization design model for a maximum number of iterations to obtain an optimized phase distribution of the array antenna;

[0015] S9: According to the electrical performance requirements of the antenna design, determine whether the change in the electrical performance of the optimized antenna meets the preset requirements. If so, output the optimized array antenna phase distribution; otherwise, adjust the particle swarm optimization parameters and repeat steps S5 to S9 until the preset requirements are met.

[0016] In one embodiment of the present invention, the structural parameters of the radome include:

[0017] The height, diameter, thickness of the radome and the distribution position of the array antenna inside the radome.

[0018] In one embodiment of the present invention, the material properties of the radome include:

[0019] Thermal conductivity Q, specific heat C P , the curves of dielectric constant epu and loss tangent loss changing with temperature.

[0020] In one embodiment of the present invention, the flight conditions of the radome include:

[0021] The flight altitude, flight speed and angle of attack of the radome.

[0022] In one embodiment of the present invention, the temperature distribution data and material properties of the outer surface of the radome are imported into the commercial software COMLOL in the form of an interpolation function to construct a finite element model of a high-temperature ablation radome, including:

[0023] The temperature distribution data is processed into a first data table with J rows and 3 columns using the commercial software Fluent; the format of the first data table is as follows:

[0024] (x j ,y j ,T j ), j = 1, 2, ..., J;

[0025] Where j represents the jth grid node in the fluid calculation grid model of the radome, J represents the total number of grid nodes in the fluid calculation grid model, and x j ,y j represents the coordinates of the grid nodes, T j Indicates the temperature corresponding to the jth grid node;

[0026] Data on the variation of material properties with temperature are extracted from the material properties of the radome, and the data on the variation of material properties with temperature are processed into a second data table with K rows and 2 columns; the format of the second data table is as follows:

[0027] (T k ,value k ),k=1,2,…,K;

[0028] Where k represents the kth sampling point in the temperature curve of the radome material, K represents the total number of sampling points, and T k Indicates the temperature of the sampling point, value k Indicates the material parameter value corresponding to the kth sampling point;

[0029] The first data table and the second data table are imported into the interpolation function interface of the commercial software COMLOL to construct the temperature interpolation function T(x, y), the thermal conductivity interpolation function Q(T), and the specific heat capacity interpolation function C P (T), dielectric constant interpolation function epu(T) and loss tangent interpolation function loss(T), to simulate the state of radome ablation;

[0030] In the radome material parameter setting in the commercial software COMLOL, the thermal conductivity is set to Q(T) and the specific heat capacity is set to C P (T), the dielectric constant is set to epu(T), the loss tangent is set to loss(T), and the temperature boundary condition is set to T(x,y) in the boundary condition setting to obtain the finite element model of the high-temperature ablation antenna cover.

[0031] In one embodiment of the present invention, MATLAB is used to randomly generate a phase distribution of an antenna array in a radome based on particle swarm optimization parameters, and a scanning angle of the antenna array is specified, including:

[0032] The rand function in MATLAB is used to randomly generate the phase distribution of each array unit in the antenna array inside the radome. The number of array units is equal to the number of individuals in the optimization population in the particle swarm optimization parameters. The phase distribution of the array unit ranges from [-180°, 180°], and the scanning angle of the array unit is obtained by default.

[0033] In one embodiment of the present invention, the electrical performance of the array antenna includes:

[0034] Main beam peak G0, main beam position B0, left first sidelobe level LSSL0, right first sidelobe level RSLL0 and main beam half power beamwidth HPPBW0.

[0035] In one embodiment of the present invention, the commercial software COMLOL is used to obtain the second far-field pattern of the array antenna after the high-temperature ablation radome is loaded based on the finite element model, phase distribution and scanning angle of the high-temperature ablation radome, so as to determine the electrical performance of the array antenna after the high-temperature ablation radome is loaded, including:

[0036] Using the commercial software COMLOL, based on the finite element model of the high-temperature ablation radome, the phase distribution and scanning angle of the array unit corresponding to each individual in the optimized population are simulated to obtain the second far-field pattern of the array antenna after the high-temperature ablation radome is loaded;

[0037] The COMSOL Multiphysics with MATLAB interface of the commercial software COMSOL is used for joint simulation with MATLAB to extract the main beam peak G1 after loading the high-temperature ablation radome, the main beam position B1 after loading, the left first sidelobe level LSSL1 after loading, the right first sidelobe level RSLL1 after loading, and the main beam half-power beam width HPPBW1 after loading from the second far-field pattern;

[0038] Based on the main beam peak G0, the main beam position B0, the left first sidelobe level LSSL0, the right first sidelobe level RSLL0, the main beam half-power lobe width HPPBW0, the loaded main beam peak G1, the loaded main beam position B1, the loaded left first sidelobe level LSSL1, the loaded right first sidelobe level RSLL1 and the loaded main beam half-power lobe width HPPBW1, the electrical performance of the array antenna after loading the high-temperature ablation antenna cover is obtained; wherein the electrical performance of the array antenna after loading the high-temperature ablation antenna cover includes: aiming error BSE, maximum gain loss TLM, left first sidelobe level loss TLL, right first sidelobe level loss TLR and main beam half-power lobe width loss TLB.

[0039] In one embodiment of the present invention, the optimization design model is as follows:

[0040]

[0041] Among them, φ n represents the phase distribution of the nth array element in the antenna array, BSE1 represents the aiming error caused by the radome under the specified flight condition, TLM1 represents the maximum gain loss caused by the radome under the specified flight condition, TLL1 represents the level loss of the left first sidelobe caused by the radome under the specified flight condition, TLR1 represents the level loss of the right first sidelobe caused by the radome under the specified flight condition, TLB1 represents the main beam half-power lobe width loss caused by the radome under the specified flight condition, BSE0, TLM0, TLL0, TLR0 and TLB0 represent the normalization coefficients corresponding to the electrical performance of the array antenna under the specified flight condition.

[0042] In one embodiment of the present invention, using a particle swarm optimization algorithm through MATLAB, an iterative processing process of the maximum number of iterations of the optimization design model is performed, including:

[0043] The phase distribution of all array units in the antenna array is regarded as a particle group, and each phase distribution is regarded as a particle; for each particle in the particle group, the fitness value of the particle is obtained by using the optimization design model;

[0044] The best fitness value among all particles is selected as the optimal individual fitness value. If the optimal individual fitness value is better than the optimal individual fitness value obtained in the previous iterative processing, the individual optimal position and the global optimal position of the particle swarm are updated according to the update formula, and the updated individual optimal position and the global optimal position of the particle swarm are used for the next iterative processing.

[0045] Beneficial effects of the present invention:

[0046] In the solution provided by the present invention, based on the data of the temperature distribution of the antenna cover in the working environment and the change of material properties with temperature, when establishing the finite element model of the high-temperature ablation antenna cover, the part of the antenna cover whose temperature exceeds the ablation temperature is reconstructed as an air cover, thereby obtaining the finite element model of the high-temperature ablation antenna cover. The electrical performance of the array antenna after loading the high-temperature ablation antenna cover is obtained by full-wave calculation using COMLOL, and the optimal phase distribution of the array antenna in the antenna cover is iteratively solved based on the particle swarm optimization algorithm, thereby compensating for the influence of high-temperature ablation on the electrical performance of the antenna cover. While ensuring the compensation accuracy, the influence of high-temperature ablation on the electrical performance of the antenna cover can be taken into account, and it has a high compensation effect and accuracy, and is widely applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram of the steps of a method for compensating electrical performance of a high-temperature ablation radome based on array element phase adjustment provided by an embodiment of the present invention;

[0048] Figure 2 A schematic flow chart of a method for compensating electrical performance of a high-temperature ablation radome based on array element phase adjustment provided in an embodiment of the present invention;

[0049] Figure 3 A schematic structural diagram of an aircraft radome provided by an embodiment of the present invention;

[0050] Figure 4 A schematic diagram of a finite element model of a high temperature ablation radome provided by an embodiment of the present invention;

[0051] Figure 5 A temperature distribution cloud diagram of the outer surface of a radome provided in an embodiment of the present invention;

[0052] Figure 6a-6d A schematic diagram of a curve showing data of material properties changing with temperature provided by an embodiment of the present invention;

[0053] Figure 7 A phase distribution diagram of a compensated array antenna provided by an embodiment of the present invention;

[0054] Figure 8 A directional diagram of a compensated front and rear array antenna provided by an embodiment of the present invention.

[0055] Reference numerals:

[0056] 1-radome outer surface boundary, 2-fluid calculation inflow boundary, 3-fluid calculation outlet boundary. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0058] See the schematic diagram of the steps of the method for compensating the electrical performance of the high temperature ablation antenna cover based on the phase adjustment of the array element provided in the embodiment of the present invention. Figure 1 , please refer to the corresponding flow chart Figure 2 , the following will combine Figure 1 and Figure 2 Each step of the method is introduced separately.

[0059] An embodiment of the present invention provides a method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment, which may include:

[0060] S1: Determine the structural parameters and material properties of the aircraft radome.

[0061] Specifically, the structural parameters of the radome, such as Figure 3 As shown, it may include:

[0062] The height, diameter, thickness of the radome and the distribution position of the array antenna inside the radome.

[0063] The design of the structural parameters of the radome can be based on Figure 3 The design is shown in the relevant parameters, and you can also design it according to specific needs.

[0064] The material properties of the radome can include:

[0065] Thermal conductivity Q and specific heat C of the material P , the characteristics of dielectric constant epu and loss tangent loss changing with temperature.

[0066] S2: Determine the flight condition of the radome of the aircraft according to the flight curve of the aircraft.

[0067] Specifically, the flight conditions of the radome may include:

[0068] The flight altitude, flight speed and angle of attack of the radome.

[0069] S3: Using the commercial software Fluent, a fluid calculation grid model of the flow field and the aircraft's radome is established according to the structural parameters and flight conditions, thereby obtaining the temperature distribution data of the outer surface of the radome.

[0070] Specifically, in the commercial software Fluent, a steady-state thermal analysis is performed on the aircraft radome according to the structural parameters and flight conditions, and a fluid calculation grid model of the flow field and the aircraft radome is established, such as Figure 4 As shown, the temperature distribution data of the outer surface of the radome is obtained. Figure 4 It can be seen that the fluid calculation grid model of the radome can include: the radome outer surface boundary 1, the fluid calculation inflow boundary 2 and the fluid calculation outlet boundary 3. For the corresponding radome outer surface temperature distribution cloud map, please refer to Figure 5 .

[0071] S4: The temperature distribution data of the outer surface of the radome and the data on the variation of material properties with temperature are imported into the commercial software COMLOL in the form of interpolation functions to construct a finite element model of the high-temperature ablation radome.

[0072] Specifically, for S4, it may include:

[0073] S41, extracting temperature distribution data of the outer surface of the antenna cover from the commercial software Fluent, and processing the temperature distribution data into a first data table with J rows and 3 columns; the format of the first data table is as follows:

[0074] (x j ,y j ,T j ), j = 1, 2, ..., J;

[0075] Where j represents the jth grid node in the fluid calculation grid model of the radome, J represents the total number of grid nodes in the fluid calculation grid model, and x j ,y j represents the coordinates of the grid nodes, T j Represents the temperature corresponding to the jth grid node.

[0076] S42, extracting data on the variation of material properties with temperature from the material properties of the radome, and processing the data on the variation of material properties with temperature into a second data table with K rows and 2 columns; the format of the second data table is as follows:

[0077] (T k ,value k ),k=1,2,…,K;

[0078] Where k represents the kth sampling point in the temperature curve of the radome material, K represents the total number of sampling points, and T k Indicates the temperature of the sampling point, value k It represents the material parameter value corresponding to the kth sampling point. It can be understood that the material property is a function of temperature, which will change with temperature. The material parameter value is the value corresponding to the sampling point in the material property.

[0079] For a detailed diagram of the curve of material properties changing with temperature, please refer to Figure 6a-6d ;in, Figure 6a represents the specific heat capacity C of the radome P The temperature variation curve, Figure 6b A graph showing the thermal conductivity Q of the radome as a function of temperature, Figure 6c A graph showing the change in the dielectric constant epu of the radome with temperature. Figure 6d A graph showing how the loss tangent of the radome changes with temperature.

[0080] S43, importing the first data table and the second data table into the interpolation function interface of the commercial software COMLOL, constructing the temperature interpolation function T(x, y), the thermal conductivity interpolation function Q(T), and the specific heat capacity interpolation function C P (T), dielectric constant interpolation function epu(T) and loss tangent interpolation function loss(T) are used to simulate the state of radome ablation.

[0081] Specifically, extrapolation interpolation is adopted for the dielectric constant interpolation function epu(T) and the loss tangent interpolation function loss(T), that is, when the temperature exceeds the ablation temperature, the dielectric constant is extrapolated to 1 and the loss tangent is extrapolated to 0. The part of the antenna cover whose temperature exceeds the ablation temperature is regarded as an air cover to simulate the ablation state of the antenna cover. The selected coordinate system can be the two-dimensional global coordinate system O-xy of COMSOL, and T represents the temperature variable.

[0082] S44, in the radome material parameter setting in the commercial software COMLOL, set the thermal conductivity to Q(T) and the specific heat capacity to C P (T), the dielectric constant is set to epu(T), the loss tangent is set to loss(T), and the temperature boundary condition is set to T(x,y) in the boundary condition setting to obtain the finite element model of the high-temperature ablation antenna cover.

[0083] The method for compensating the electrical properties of a high-temperature ablation radome provided in an embodiment of the present invention reconstructs the portion of the radome where the temperature exceeds the ablation temperature into an air radome based on the temperature distribution of the radome in a working environment and the data on changes in material properties with temperature, thereby obtaining a finite element model of the high-temperature ablation radome.

[0084] S5: Using MATLAB, based on the particle swarm optimization parameters, the phase distribution of the antenna array in the radome is randomly generated, and the scanning angle of the antenna array is specified; the particle swarm optimization parameters include: the number of individuals in the optimization population and the maximum number of iterations.

[0085] Specifically, for S5, using MATLAB, based on particle swarm optimization parameters, randomly generating the phase distribution of the antenna array in the radome and specifying the scanning angle of the antenna array may include:

[0086] The rand function in MATLAB is used to randomly generate the phase distribution of each array unit in the antenna array inside the radome; the number of array units is equal to the number of individuals in the optimization population in the particle swarm optimization parameters, the phase distribution of the array unit ranges from [-180°, 180°], and the scanning angle of the array unit can be obtained by preset.

[0087] It can be understood that a set of electric point dipoles can be used to represent the array antenna in the antenna cover. The dipole moment direction of each electric point dipole is parallel to the x direction, and the corresponding current is:

[0088]

[0089] Where n represents the number of the electric point dipole, A n represents the amplitude of the nth current, e represents the natural constant, j represents the imaginary unit, and N represents the total number of electric point dipoles; φ n represents the phase of the nth current, which corresponds to the phase distribution of the nth array unit.

[0090] The number of individuals and the maximum number of iterations of the optimization population in the particle swarm optimization parameters are set, and the population is randomly generated using the rand function in MATLAB. Each individual in the population corresponds to a phase distribution of an array antenna, thereby obtaining the phase distribution of each array unit in the antenna array in the radome.

[0091] S6: Using the commercial software COMLOL, based on the phase distribution and the scanning angle, the first far-field pattern of the array antenna is obtained, and the electrical performance of the array antenna is extracted from the first far-field pattern.

[0092] Specifically, for S6, it may include:

[0093] S61, using COMSOL simulation to simulate the phase distribution and scanning angle of the array unit in the array antenna corresponding to each individual in the population, to obtain a first far-field radiation pattern of the array antenna.

[0094] S62, using the COMSOL Multiphysics with MATLAB interface of the commercial software COMSOL and MATLAB co-simulation, the electrical performance of the array antenna is extracted from the first far-field pattern.

[0095] The electrical performance of the array antenna may include:

[0096] Main beam peak G0, main beam position B0, left first sidelobe level LSSL0, right first sidelobe level RSLL0 and main beam half power beamwidth HPPBW0.

[0097] S7: Using the commercial software COMLOL, based on the finite element model, phase distribution and scanning angle of the high-temperature ablation radome, the second far-field radiation pattern of the array antenna after the high-temperature ablation radome is loaded is obtained, thereby determining the electrical performance of the array antenna after the high-temperature ablation radome is loaded.

[0098] Specifically, for S7, it may include:

[0099] S71, using the commercial software COMLOL, based on the finite element model of the high-temperature ablation radome, simulates the phase distribution and scanning angle of the array unit corresponding to each individual in the optimized population to obtain the second far-field radiation pattern after the array antenna is equipped with the high-temperature ablation radome.

[0100] S72, using the COMSOL Multiphysics with MATLAB interface of the commercial software COMSOL and MATLAB joint simulation, the main beam peak G1 after loading the high-temperature ablation antenna cover, the main beam position B1 after loading, the left first sidelobe level LSSL1 after loading, the right first sidelobe level RSLL1 after loading and the main beam half-power beam width HPPBW1 after loading are extracted from the second far-field radiation pattern.

[0101] S73, based on the main beam peak G0, the main beam position B0, the left first sidelobe level LSSL0, the right first sidelobe level RSLL0, the main beam half-power lobe width HPPBW0, the loaded main beam peak G1, the loaded main beam position B1, the loaded left first sidelobe level LSSL1, the loaded right first sidelobe level RSLL1 and the loaded main beam half-power lobe width HPPBW1, obtain the electrical performance of the array antenna after loading the high-temperature ablation antenna cover; wherein the electrical performance of the array antenna after loading the high-temperature ablation antenna cover includes: aiming error BSE, maximum gain loss TLM, left first sidelobe level loss TLL, right first sidelobe level loss TLR and main beam half-power lobe width loss TLB.

[0102] Specifically, for the aiming error BSE, BSE = |B0-B1|;

[0103] For gain maximum loss TLM, TLM = |TLM0-TLM1|;

[0104] For the left first sidelobe level loss TLL, TLL = |TSLL0-TSLL1|;

[0105] For the right first sidelobe level loss TLR, TLR = |RSLL0-RSLL1|;

[0106] For the main beam half-power beamwidth loss TLB, TLB=|HPBW0-HPBW1|.

[0107] S8: Based on the phase distribution of the antenna array and the electrical performance of the array antenna after loading the high-temperature ablation radome, an optimization design model is established; the particle swarm optimization algorithm is used through MATLAB to iterate the optimization design model for the maximum number of iterations to obtain the optimized phase distribution of the array antenna.

[0108] Specifically, for S8, it may include:

[0109] S81. Establish an optimization design model based on the phase distribution of the antenna array and the electrical performance of the array antenna after loading the high-temperature ablation radome, which may include:

[0110] The phase distribution of each array element in the array antenna obtained in step S5 is used as the design variable, and the aiming error BSE, the maximum gain loss TLM, the left first sidelobe level loss TLL, the right first sidelobe level loss TLR and the main beam half-power beamwidth loss TLB obtained in step S7 are used as the design targets to establish an optimization design model. The optimization design model is as follows:

[0111]

[0112] Among them, φ n Represents the phase distribution of the nth array element in the antenna array, -180°≤φ n ≤180°, n=1,2,…,N, BSE1 represents the aiming error caused by the radome under the specified flight condition, TLM1 represents the maximum gain loss caused by the radome under the specified flight condition, TLL1 represents the left first sidelobe level loss caused by the radome under the specified flight condition, TLR1 represents the right first sidelobe level loss caused by the radome under the specified flight condition, TLB1 represents the main beam half-power beamwidth loss caused by the radome under the specified flight condition, BSE0, TLM0, TLL0, TLR0 and TLB0 represent the normalization coefficients corresponding to the electrical performance of the array antenna under the specified flight condition.

[0113] S82, using the particle swarm optimization algorithm through MATLAB, iterating the optimization design model for the maximum number of iterations to obtain the optimized array antenna phase distribution.

[0114] Specifically, using the particle swarm optimization algorithm in MATLAB, an iterative processing process of the maximum number of iterations of the optimization design model is performed, including:

[0115] The phase distribution of all array units in the antenna array is regarded as a particle group, and each phase distribution is regarded as a particle; for each particle in the particle group, the fitness value of the particle is obtained using the optimization design model;

[0116] The best fitness value among all particles is selected as the optimal individual fitness value. If the optimal individual fitness value is better than the optimal individual fitness value obtained in the previous iterative processing, the individual optimal position and the global optimal position of the particle swarm are updated according to the update formula, and the updated individual optimal position and the global optimal position of the particle swarm are used for the next iterative processing.

[0117] The particle velocity and position update formulas are standard formulas and will not be repeated here. For details, please refer to the existing related technical introduction.

[0118] It can be understood that the fitness value can be the weighted sum of the aiming error and the transmission loss, and the transmission loss can include: maximum gain loss, left first sidelobe level loss, right first sidelobe level loss and main beam half-power lobe width loss. If the maximum number of iterations is set to 200, 200 corresponding iterations will be performed in step S8 to obtain the optimized array antenna phase distribution for judgment in step S9.

[0119] S9: According to the electrical performance requirements of the antenna design, determine whether the change in the electrical performance of the optimized antenna meets the preset requirements. If so, output the optimized array antenna phase distribution; otherwise, adjust the particle swarm optimization parameters and repeat steps S5 to S9 until the preset requirements are met.

[0120] Understandable, such as Figure 2As shown, after the optimized array antenna phase distribution is obtained in step S8, step S9 needs to judge whether the electrical performance change of the optimized antenna meets the preset requirements according to the electrical performance requirements of the antenna design. If the requirements are met, it is proved that the obtained optimized array antenna phase distribution meets the requirements. At this time, the optimized array antenna phase distribution is output, and the corresponding design scheme is used as the optimal design scheme; if the requirements are not met, the particle swarm optimization parameters and / or the weights corresponding to each variable in the optimization design model can be adjusted, and steps S5 to S9 are repeated until the electrical performance change of the optimized antenna obtained in step S8 meets the preset requirements. The electrical performance change of the antenna is the electrical performance of the array antenna after the high-temperature ablation radome is loaded. The preset requirements can be aiming error BSE<0.3°, maximum gain loss TLM<0.5dB, left first sidelobe level loss TLL<1dB, right first sidelobe level loss TLR<1dB and main beam half-power beamwidth loss TLB<1°. For ease of understanding, a simulation experiment is performed on the high-temperature ablation radome electrical performance compensation method based on array element phase adjustment provided in an embodiment of the present invention to more clearly demonstrate the beneficial effects of the embodiment of the present invention.

[0121] Set simulation parameters: The structural diagram of an aircraft radome is as follows: Figure 3 As shown, the array antenna is 300mm away from the bottom of the radome, and a total of 1×16 electric point dipoles are arranged on the array surface of the array antenna, with a spacing of λ / 2, λ represents the operating wavelength, the operating frequency can be 9.4GHz, the initial phase of the array element can be uniform and in phase, and the scanning angle can be 10°; the outer wall diameter of the bottom of the radome can be 500mm, the inner wall diameter can be 467.28mm, the height can be 1000mm, the material can be quartz glass, the dielectric constant of the material at room temperature can be 3.8, and the loss tangent can be 0.0005. The flight conditions of the aircraft can be: flight altitude 10km, flight speed 7Ma, angle of attack 12°.

[0122] In the commercial software FLUENT, the aerodynamic thermal analysis of the aircraft radome is carried out. First, the fluid grid of the aircraft radome is divided, such as Figure 4 As shown, the incoming flow boundary condition is set to the pressure far field, and the outlet boundary condition is set to the pressure outlet. The incoming flow Mach number, air temperature, pressure and direction are determined by the flight speed, flight altitude and angle of attack respectively. The temperature distribution on the outer surface of the radome is obtained as shown in Figure 5 shown.

[0123] The temperature distribution data of the outer surface of the radome is extracted from the simulation results of Fluent. The data format is a data table. The first column of the table is the x-coordinate of the grid node of the radome, the second column is the y-coordinate, and the third column is the temperature value of the corresponding grid node. Figure 6a-6dThe radome material parameter curve shown is extracted as a data table. The first column is the temperature value, and the second column is the material parameter value corresponding to the current temperature. The above data table is imported into COMSOL to construct the temperature interpolation function T(x,y), thermal conductivity interpolation function Q(T), and specific heat capacity interpolation function C P (T), dielectric constant interpolation function epu(T) and loss tangent interpolation function loss(T), the dielectric constant interpolation function epu(T) and loss tangent interpolation function loss(T) are extrapolated, that is, when the temperature exceeds the ablation temperature, the dielectric constant is extrapolated to 1, and the loss tangent is extrapolated to 0. The part of the radome with a temperature exceeding the ablation temperature is regarded as an air hood to simulate the state of radome ablation. In the radome material parameter setting in the commercial software COMLOL, the thermal conductivity is set to Q(T) and the specific heat capacity is set to C P (T), the dielectric constant is set to epu(T), the loss tangent is set to loss(T), and the temperature boundary condition is set to T(x,y) in the boundary condition setting to obtain the finite element model of the high-temperature ablation antenna cover.

[0124] Initialize the phase distribution of the array antenna, use COMSOL to calculate the electrical performance of the array antenna before and after the high-temperature ablation antenna cover, use COMSOL Multiphysics with MATLAB interface to extract electrical performance indicators, build an optimization design model, and use the particle swarm optimization algorithm to solve the optimization model. The phase optimization results are as follows: Figure 7 As shown, the corresponding electrical performance indicators are shown in Table 1, a comparison of the electrical performance of the antenna cover before and after compensation.

[0125] Table 1 Comparison of electrical performance of radome before and after compensation

[0126] state BSE(°) TLM(dB) TLL(dB) TLR(dB) TLB(°) Uncompensated 1.33 0.91 2.78 4.48 0.73 Compensation 1 0.48 2.06 6.6 6.23 1.23 Compensation 2 0.02 2.14 0 0.02 0.71

[0127] Figure 7 In the above, Optimization 1 represents the phase distribution scheme obtained by the existing compensation method based on the geometric optics method, and Optimization 2 represents the phase distribution scheme obtained by the electrical performance compensation method of the high temperature ablation antenna cover based on the array element phase adjustment provided in the embodiment of the present invention. Figure 8 To compensate for the radiation patterns of the front and rear array antennas, Figure 8 The comparison of antenna patterns under the corresponding optimization methods can be seen in Figure 2.

[0128] from Figure 7It can be seen from Table 1 that the electrical performance of the high-temperature ablation radome is seriously deteriorated, which is reflected in the maximum gain loss of 0.91dB, the aiming error of 1.33°, the left first sidelobe level loss of 2.78dB, the right first sidelobe level loss of 4.48dB, and the half-power lobe width loss of 0.73°. It can be seen that the existing compensation method based on geometric optics can only make approximate compensation, and the effect is not significant. By adopting the compensation method provided by the present invention, the electrical performance indicators are well improved.

[0129] The method for compensating the electrical performance of a high-temperature ablation radome based on the phase adjustment of the array element provided in the embodiment of the present invention is based on the data of the temperature distribution of the radome in the working environment and the changes of the material properties with the temperature. When establishing the finite element model of the high-temperature ablation radome, the part of the radome whose temperature exceeds the ablation temperature is reconstructed as an air hood, thereby obtaining the finite element model of the high-temperature ablation radome. The electrical performance of the array antenna after loading the high-temperature ablation radome is obtained by full-wave calculation using COMLOL, and the optimal phase distribution of the array antenna in the radome is iteratively solved based on the particle swarm optimization algorithm, thereby compensating for the influence of high-temperature ablation on the electrical performance of the radome. While ensuring the compensation accuracy, the influence of high-temperature ablation on the electrical performance of the radome can be taken into account. It has a high compensation effect and accuracy, and is widely applicable.

[0130] It should be noted that in the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment, characterized in that: include: S1: Determine the structural parameters and material properties of the aircraft radome; S2: determining the flight condition of the radome of the aircraft according to the flight curve of the aircraft; S3: using commercial software Fluent, according to the structural parameters and flight conditions, a fluid calculation grid model of the flow field and the radome of the aircraft is established, thereby obtaining temperature distribution data of the outer surface of the radome; S4: The temperature distribution data and material property data of the outer surface of the radome are imported into the commercial software COMLOL in the form of interpolation functions to construct a finite element model of the high-temperature ablation radome; S5: using MATLAB, based on particle swarm optimization parameters, randomly generating the phase distribution of the antenna array in the radome, and specifying the scanning angle of the antenna array; the particle swarm optimization parameters include: the number of individuals in the optimization population and the maximum number of iterations; S6: using commercial software COMLOL, based on the phase distribution and the scanning angle, obtaining a first far-field pattern of the array antenna, and extracting electrical performance of the array antenna from the first far-field pattern; S7: using the commercial software COMLOL, based on the finite element model, phase distribution and scanning angle of the high temperature ablation radome, obtaining a second far-field pattern of the array antenna after the high temperature ablation radome is loaded, thereby determining the electrical performance of the array antenna after the high temperature ablation radome is loaded; S8: establishing an optimization design model based on the phase distribution of the antenna array and the electrical performance of the array antenna after loading the high-temperature ablation radome; using the particle swarm optimization algorithm in MATLAB, iterating the optimization design model for a maximum number of iterations to obtain an optimized phase distribution of the array antenna; S9: According to the electrical performance requirements of the antenna design, determine whether the change in the electrical performance of the optimized antenna meets the preset requirements. If so, output the optimized array antenna phase distribution; otherwise, adjust the particle swarm optimization parameters and repeat steps S5 to S9 until the preset requirements are met.

2. According to claim 1, a method for compensating electrical performance of a high temperature ablation antenna cover based on array element phase adjustment is characterized in that: The structural parameters of the radome include: The height, diameter, thickness of the radome and the distribution position of the array antenna inside the radome.

3. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 1, characterized in that: The material properties of the radome include: Thermal conductivity Q, specific heat C P , the curves of dielectric constant epu and loss tangent loss changing with temperature.

4. According to claim 1, a method for compensating electrical performance of a high temperature ablation antenna cover based on array element phase adjustment is characterized in that: The flight conditions of the radome include: The flight altitude, flight speed and angle of attack of the radome.

5. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 1, characterized in that: The temperature distribution data and material properties of the outer surface of the radome that change with temperature are imported into the commercial software COMLOL in the form of an interpolation function to construct a finite element model of the high-temperature ablation radome, including: The temperature distribution data is processed into a first data table with J rows and 3 columns using the commercial software Fluent; the format of the first data table is as follows: (x j ,y j ,T j ),j=1,2,…,J; Where j represents the jth grid node in the fluid calculation grid model of the radome, J represents the total number of grid nodes in the fluid calculation grid model, and x j ,y j represents the coordinates of the grid nodes, T j Indicates the temperature corresponding to the jth grid node; Data on the variation of material properties with temperature are extracted from the material properties of the radome, and the data on the variation of material properties with temperature are processed into a second data table with K rows and 2 columns; the format of the second data table is as follows: (T k ,value k ),k=1,2,…,K; Where k represents the kth sampling point in the temperature curve of the radome material, K represents the total number of sampling points, and T k Indicates the temperature of the sampling point, value k Indicates the material parameter value corresponding to the kth sampling point; The first data table and the second data table are imported into the interpolation function interface of the commercial software COMLOL to construct the temperature interpolation function T(x, y), the thermal conductivity interpolation function Q(T), and the specific heat capacity interpolation function C P (T), dielectric constant interpolation function epu(T) and loss tangent interpolation function loss(T), to simulate the state of radome ablation; In the radome material parameter setting in the commercial software COMLOL, the thermal conductivity is set to Q(T) and the specific heat capacity is set to C P (T), the dielectric constant is set to epu(T), the loss tangent is set to loss(T), and the temperature boundary condition is set to T(x,y) in the boundary condition setting to obtain the finite element model of the high-temperature ablation antenna cover.

6. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 1, characterized in that: The method of using MATLAB to randomly generate the phase distribution of the antenna array in the radome based on the particle swarm optimization parameters and specifying the scanning angle of the antenna array includes: The rand function in MATLAB is used to randomly generate the phase distribution of each array unit in the antenna array inside the radome. The number of array units is equal to the number of individuals in the optimization population in the particle swarm optimization parameters. The phase distribution of the array unit ranges from [-180°, 180°], and the scanning angle of the array unit is obtained by default.

7. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 6, characterized in that: The electrical properties of the array antenna include: Main beam peak G0, main beam position B0, left first sidelobe level LSSL0, right first sidelobe level RSLL0 and main beam half power beamwidth HPPBW0.

8. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 7, characterized in that: The method uses the commercial software COMLOL to obtain a second far-field pattern of the array antenna after the high-temperature ablation radome is loaded based on the finite element model, phase distribution and scanning angle of the high-temperature ablation radome, thereby determining the electrical performance of the array antenna after the high-temperature ablation radome is loaded, including: Using the commercial software COMLOL, based on the finite element model of the high-temperature ablation radome, the phase distribution and scanning angle of the array unit corresponding to each individual in the optimized population are simulated to obtain the second far-field pattern of the array antenna after the high-temperature ablation radome is loaded; The COMSOL Multiphysics with MATLAB interface of the commercial software COMSOL is used for joint simulation with MATLAB to extract the main beam peak G1 after loading the high-temperature ablation radome, the main beam position B1 after loading, the left first sidelobe level LSSL1 after loading, the right first sidelobe level RSLL1 after loading, and the main beam half-power beam width HPPBW1 after loading from the second far-field pattern; Based on the main beam peak G0, the main beam position B0, the left first sidelobe level LSSL0, the right first sidelobe level RSLL0, the main beam half-power lobe width HPPBW0, the loaded main beam peak G1, the loaded main beam position B1, the loaded left first sidelobe level LSSL1, the loaded right first sidelobe level RSLL1 and the loaded main beam half-power lobe width HPPBW1, the electrical performance of the array antenna after loading the high-temperature ablation antenna cover is obtained; wherein the electrical performance of the array antenna after loading the high-temperature ablation antenna cover includes: aiming error BSE, maximum gain loss TLM, left first sidelobe level loss TLL, right first sidelobe level loss TLR and main beam half-power lobe width loss TLB.

9. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 1, characterized in that: The optimization design model is as follows: Among them, φ n represents the phase distribution of the nth array element in the antenna array, BSE1 represents the aiming error caused by the radome under the specified flight condition, TLM1 represents the maximum gain loss caused by the radome under the specified flight condition, TLL1 represents the level loss of the left first sidelobe caused by the radome under the specified flight condition, TLR1 represents the level loss of the right first sidelobe caused by the radome under the specified flight condition, TLB1 represents the main beam half-power lobe width loss caused by the radome under the specified flight condition, BSE0, TLM0, TLL0, TLR0 and TLB0 represent the normalization coefficients corresponding to the electrical performance of the array antenna under the specified flight condition.

10. The method for compensating electrical performance of a high temperature ablation radome based on array element phase adjustment according to claim 1, characterized in that: The process of performing an iterative processing of the maximum number of iterations on the optimization design model using a particle swarm optimization algorithm through MATLAB includes: The phase distribution of all array units in the antenna array is regarded as a particle group, and each phase distribution is regarded as a particle; for each particle in the particle group, the fitness value of the particle is obtained by using the optimization design model; The best fitness value among all particles is selected as the optimal individual fitness value. If the optimal individual fitness value is better than the optimal individual fitness value obtained in the previous iterative processing, the individual optimal position and the global optimal position of the particle swarm are updated according to the update formula, and the updated individual optimal position and the global optimal position of the particle swarm are used for the next iterative processing.

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