6 results about "Computational electromagnetics" patented technology

This invention belongs to the field of computational electromagnetics numerical simulation and provides a simulation method for electromagnetic scattering of thin-coated targets based on Schur complement preconditions. First, for the IBC scattering target to be solved, equivalent surface current and equivalent surface magnetic current are introduced as independent unknowns. The electromagnetic scattering solution equation is established using SDIE and then discretized. Next, the impedance matrix is ​​decomposed into near-field and far-field matrices using an octree structure. For the near-field matrix, key operator sub-blocks are explicitly assembled and extracted. Then, approximate operators in block diagonal form and Schur complement operators are constructed and approximately inverted. Simultaneously, the diagonal product of intermediate blocks is pre-calculated and stored based on the approximate operators. Finally, the constructed preconditions are applied to the GMRES iterative solver. When the iteration error reaches the preset convergence criterion, the current and magnetic current distributions on the target surface are output. Further calculations of radiation characteristic parameters such as the target's radar cross section are then performed, achieving low-cost, high-efficiency, and easily parallelizable electromagnetic simulation solutions.

The application belongs to the technical field of computational electromagnetics, and discloses a numerical calculation method for simulating electromagnetic wave propagation characteristics in time-varying plasma, which is a three-dimensional Newton-HIE-FDTD method for efficiently simulating electromagnetic wave propagation in time-varying plasma based on a mixed explicit-implicit finite-difference time-domain method and Newton's second law of motion. The method inherits the advantages of the Newton-ADE-FDTD method, accurately represents the time-varying electron density through the time derivative, and can accurately capture the rich dynamic characteristics of the time-varying plasma. On this basis, the method also integrates the advantages of the HIE-FDTD method, so that the time step of the algorithm is only restricted by the grid size in two directions. Compared with other simulation methods based on time-varying plasma, the method is more efficient in calculation, and is particularly suitable for the analysis and simulation of electromagnetic wave propagation characteristics in time-varying plasma.

This invention belongs to the field of numerical simulation in computational electromagnetics, specifically a non-uniform conformal FDTD method based on submesh technology. This invention introduces non-uniform conformal geometric corrections within the submesh to achieve high-precision fitting of curved surface boundaries, reducing step approximation errors and improving the accuracy of field calculations near the boundaries. At the master-submesh interface, a bidirectional coupling transfer is established that simultaneously satisfies line integral conservation and flux conservation, avoiding disruption of the conservation relationships required by the non-uniform conformal FDTD method. This effectively suppresses numerical reflections at the interface, reduces energy non-physical errors, and improves long-term stability. Furthermore, by using fine meshes only in the neighborhood of local microstructures and coordinating with time sub-cycle progression, global mesh refinement and the global time step being limited by the smallest unit are avoided, significantly reducing storage and computation time overhead while maintaining accuracy. This invention balances geometric modeling accuracy, interface stability, and computational efficiency, and has high engineering application value.

The application discloses a target echo classification method and system based on multi-modal data fusion, relates to the technical field of computational electromagnetics, and solves the technical problems of classification accuracy reduction of a model in a noise environment, limited generalization ability, and large performance fluctuation when the distribution of modal data changes; the weight of each feature is analyzed when modeling the time sequence dependence of BiLSTM, global information is reserved through cross-modal fusion after the features are removed, cross fusion focuses on key discriminant features after the features are removed, and both can take into account information integrity and calculation efficiency. The contribution of different modal features to the classification result is dynamically adjusted through the hidden state of GRU. If some modal data is missing, the original fusion path can still use other modal information, and the screening fusion path can depend on the key features of the remaining modal. The balance between redundant feature reservation and key feature screening can reduce the sensitivity of the model to specific noise patterns.

The application discloses a PIN diode modeling and simulation method based on LP-CDI-FDTD, belongs to the field of computational electromagnetics, microwave technology and circuit simulation, and comprises the following steps: firstly, an equivalent lumped parameter model of a semiconductor device is established, and a voltage-current relationship thereof is obtained; then, the relationship is converted into an equivalent current density, and is embedded into a Maxwell curl equation according to the relationship between an electric field and a voltage, so as to construct an electromagnetic-circuit coupling equation set; further, a leapfrog compliant divergence unconditional stable time domain finite difference method is adopted to discretize the coupling equation set, and a discrete updating equation is obtained; finally, iterative calculation is carried out according to the equation, and electromagnetic fields and device states are synchronously updated. The method realizes the inherent strong coupling between full-wave electromagnetic fields and semiconductor physical processes, and breaks through the time step restriction caused by a CFL condition in traditional methods by using the unconditional stability of the algorithm, so that the calculation efficiency can be significantly improved when simulating a device containing a fine structure.

The application relates to a SAR waveform design method combined with electromagnetic characteristics and K-means clustering, comprising the following steps: obtaining target scattering characteristic data based on a computational electromagnetic technique; constructing a signal model of a SAR one-dimensional range image based on the target scattering characteristic data; constructing a target function representing SAR waveform design by taking a signal-to-clutter ratio as an optimization criterion based on the signal model; constructing an original mathematical model of a SAR waveform design optimization problem by applying a constant modulus constraint and a similarity constraint to the target function; and converting the original mathematical model into a convex optimization problem and finally iteratively solving the convex optimization problem to obtain a SAR waveform. The application improves the dark weak target detection capability through azimuth angle domain scattering feature grouping and robust optimization.