This work presents a set of algorithmic and architectural improvements to the Physical Optics (PO) method, aimed at enhancing its applicability to industrial-scale electromagnetic simulations. Building on previous research in diffraction modeling, relational databases-specifically PostgreSQL with its geospatial extension PostGIS-have been adopted to manage large volumes of geometric and intermediate data efficiently. The Gordon integral has been implemented natively in C within the database engine, significantly reducing computation time. Additionally, native spatial indexing and memory-aware data structures have enabled the simulation of complex scenarios on standard desktop hardware. An interpolation strategy has been introduced to accelerate ISAR image generation, allowing the reuse of previously computed integrals under small variations in frequency and scattering direction. The proposed framework eliminates memory bottlenecks and improves scalability, demonstrating its effectiveness through radar cross-section (RCS) and ISAR benchmarks. These results confirm the viability of database-driven PO simulations for real-world applications.

This paper presents recent enhancements of the RL-GO solver in Simcenter Feko, achieving significant improvements in computational efficiency and numerical accuracy. The proposed improvements reduce simulation runtimes, in some cases by up to two orders of magnitude, while maintaining high-fidelity results. Key enhancements include a more efficient ray-beam strategy and an adaptive integration method driven solely by geometric criteria. These improvements are validated through representative examples, confirming the robustness and scalability of the enhanced RL-GO solver.

This paper presents a deep learning approach for direction-of-arrival (DOA) estimation using convolutional neural networks (CNNs). Building upon recent advances in neural architectures for signal processing, we propose a CNN model that directly estimates incident angles from raw temporal samples collected by non-uniform linear antenna arrays. The network is trained using synthetic data generated under varying conditions, including different numbers of signal sources and signal-to-noise ratios (SNRs). The proposed architecture demonstrates high accuracy in both single-source and multi-source scenarios, with robustness to noise and array geometry variations. Experimental results show that increasing the training dataset size significantly improves performance in complex environments. The model maintains reliable performance across SNR levels ranging from 30dB to 0dB. These findings highlight the potential of CNN-based methods for scalable and accurate DOA estimation in real-world applications.

This paper describes some of the new features in the commercial electromagnetic software Altair Feko. These include more versatile ground treatment, RL-GO (ray launching geometrical optics) performance improvements, and combined MoM/MTL extensions.

A new ray-tracing acceleration technique is presented for electromagnetic simulation problems using the Uniform Theory of Diffraction and meshes of planar facets. The innovation involves using relational databases to accurately store spatial information, enabling spatial indexing through space partitioning with R-trees. This technique effectively reduces the computational cost of several critical phases, including the shadowing test. Additionally, there are multiple advantages to utilizing this technology, such as automated memory and disk management along with a query planner that organizes the instructions automatically. Direct rays, multiple reflections, multiple transmissions, simple diffraction, and combinations of these effects have been implemented in PostgreSQL and its spatial library PostGIS. Compared to traditional techniques that employ Angular Z-Buffer acceleration and store information solely in RAM using a lowlevel language, this approach decreases memory usage by more than 90% in complex scenarios. It also shows a decrease in execution time by more than half when the scenario is sufficiently complex.

When applying the Uniform Theory of Diffraction asymptotic technique, the ray-tracing computational step is the most intensive in terms of computer resources and execution time. This step consists of calculating every possible ray path between a source and an observation point. The second step consists of calculating the electromagnetic contribution of each path, and is generally negligible in relation to the first one.

This paper describes some of the latest features in the commercial electromagnetic software Altair Feko. These include the impedance sheet formulation to model multilayer frequency selective surface (FSS) radomes and coatings, method-of-moments (MoM) hybridised with faceted uniform theory of diffraction (UTD), shooting and bouncing rays (SBR) hybridised with standard ray tracing (SRT), and MLFMM parallel efficiency improvements.

A new Faceted UTD solver as implemented in Altair Feko is introduced here. The solver is based on UTD (Uniform Theory of Diffraction) applied to planar and arbitrarily convex curved surfaces meshed with planar triangles. It is most suitable for antenna placement applications in the high frequency regime.

This article presents a technique for the computation of the monostatic radar cross section of complex objects based on a combination of macro-basis functions (MBFs) and the multilevel fast multipole algorithm. An initial pool of excitation-independent MBFs is first obtained, generating the corresponding reduced coupling matrix as well as the multipole data. For each excitation, ray-tracing processing is performed, extracting a number of critical points that are used to obtain a mask that allows to dynamically select the basis functions to be considered in the analysis. This strategy allows a noticeable reduction in the size of the problems with minimal CPU-time preprocessing overhead.

A comparison between Ma-Rokhlin-Wandzura (MRW) and double exponential (DE) quadrature rules for numerical integration of method of moments (MoM) matrix entries with singular behavior is presented for multilayer periodic structures. Non Uniform Rational B-Splines (NURBS) modelling of the layout surfaces is implemented to provide high-order description of the geometry. The comparison is carried out in order to show that quadrature rule is more suitable for MoM matrix computation in terms of sampling, accuracy of computation of MoM matrix, and CPU time consumption. The comparison of CPU time consumption shows that the numerical integration with MRW samples is roughly 15 times faster than that numerical integration using DE samples for results with similar accuracies. These promising results encourage to carry out a comparison with results obtained in previous works where a specialized approach for the specific analysis of split rings geometries was carried out. This previous approach uses spectral MoM version with specific entire domain basis function with edge singularities defined on split ring geometry. Thus, the previous approach provides accurate results with low CPU time consumption to be compared. The comparison shows that CPU time consumption obtained by MRW samples is similar to the CPU time consumption required by the previous work of specific analysis of split rings geometries. The fact that similar CPU time consumptions are obtained by MRW quadrature rules for modelling of general planar geometries and by the specialized approach for split ring geometry provides an assessment for the usage of the MRW quadrature rules and NURBS modelling. This fact provides an efficient tool for analysis of reflectarray elements with general planar layout geometries, which is suitable for reflectarray designs under local periodicity assumption where a huge number of periodic multilayer structures have to be analyzed.

In recent years, the characteristic basis function method has been developed as an efficient approach for the solution of large electromagnetic radiation or scattering problems. According to this technique, the currents over the scenario under analysis are defined using a set of pre-computed characteristic basis functions, associated with a number of blocks into which the geometry is partitioned. This involves some computational advantages due to the reduction of the number of unknowns compared to conventional approaches. However, additional pre-processing time is introduced due to the computation of the CBFs and the reduced coupling matrix. A novel strategy is presented in this study in order to accelerate the generation of the reduced matrix, based on the application of the multilevel fast multipole algorithm.

This letter presents an efficient approach for the electromagnetic analysis of complex scenarios involving transmitting antennas moving along predetermined trajectories. In order to efficiently reduce the size of the problem for each position of the antenna, we propose a technique based on macro basis functions that are dynamically generated using a ray-tracing analysis. The multilevel fast multipole algorithm is also included in order to reduce the memory consumption and speed up the solution process. Some representative test cases serve to validate the efficiency and performance of the proposed approach.

An evaluation of monostatic radar cross section (RCS) response in the near-field range was performed for several targets with different and complex topologies. The main objective was to provide and validate an efficient tool based on electromagnetic (EM) simulations to characterize a traffic scenario. Thus, a novel method based on the combination of geometrical theory of diffraction (GTD) and physical optics (PO) was used to estimate RCS, and the results were compared with the method of moments (MoM) methodology. The simulations were experimentally validated using a commercial vehicular frequency-modulated continuous wave (FMCW) radar at 24 GHz. With this simple measurement system, RCS measurements can be made using an easier and cheaper process to obtain RCS response in the near-field range, which is the most usual situation for traffic applications. A reasonable agreement between the measurements and the EM simulations was observed, validating the proposed methodology in order to efficiently characterize the RCS of targets typically found in real traffic scenarios.

A novel approach for the analysis and design of radomes is presented. It uses full domain macro-basis functions obtained from the Characteristic Basis Function Method (CBFM), for modeling the radome structure. The presented approach can be used to analyze arbitrary-shaped radome antennas with several material layers composed by different thickness and different dielectrics. Some cases of study are presented in order to validate the new method.

The multilevel fast multipole algorithm is a popular technique that enables the efficient solution of the method of moments (MoM) matrix equations. In this work, the authors address the adaptation of this method to the compute unified device architecture (CUDA), a relatively new computing infrastructure provided by NVIDIA, and the authors take into account some of the limitations that appear when the geometry under analysis becomes too large to fit into the memory of graphics processing units.

This document presents a numerical approach for the solution of large electromagnetic problems using a preliminary ray-tracing analysis in order to determine the number of high-level macro-basis functions to be assigned to each block. It is especially tailored to problems with multiple sources or excitations. We provide expressions to update the threshold levels for the truncation of the number of Macro Basis Functions based exclusively on the position of the sources or including their radiation pattern.

In this work, a computer tool for the simulation of the responses of Frequency Modulated-Continuous Wave radar systems in Urban Traffic Scenes is presented. The radar echoes including frequency shifts due to distance and object speeds are computed using a new hybrid technique that combines Method of Moments, Physical Optics and Geometrical Theory of Diffraction. Arbitrarily time-shaped radar sequences can be set for obtaining output parameters like Doppler Spectrum, beat signals in frequency and time domains, distances and speeds of echoes, etc. The technique is efficient and accurate for solving the electrically large and multiscale problem that appears in the simulation of these systems in urban complex scenarios. Representative results are presented.

It is presented a new hybrid technique combining Method of Moments, Physical Optics and Geometrical Theory of Diffraction for the analysis of the vehicle to vehicle and vehicle to infraestructure radio-wave channel in urban traffic scenes. The technique is efficient and accurate for solving the electrically large and multiscale problem that appears in the analyses of these channels. Representative results and cross validations are presented.