Adnan Alhaj Hasan

Physics-informed neural networks (PINNs) have developed from residual constrained neural approximations into a heterogeneous family of scientific computing formulations, combining governing equations, observations, numerical operators, and optimization. This review examines how formulation, training, and evaluation interact within an integrated computational methodology. A structured and iterative review assembled 853 records from Scopus, IEEE Xplore, ScienceDirect, MDPI, reference tracing, and topic-specific searches; 514 references are cited in the revised manuscript. The review analyzes representation, physics enforcement, differentiation, collocation, loss construction, optimization, architectural and theoretical developments, and multidimensional evaluation. The analysis shows that reliability depends on these coupled choices and that no universal architecture, optimizer, enforcement strategy, or sampling strategy exists. An evidence-linked co-design framework, qualitative design-performance dependency matrix, and failure-mode diagnostic map are therefore developed to connect design choices with performance and guide redesign. Low prediction or residual error alone does not establish conservation, stability, robustness, uncertainty calibration, or computational efficiency. The open PINN Review Atlas links the synthesis to evidence, metrics, mathematical formulations, and related data as an interactive resource to help researchers explore the field and support future studies. PINNs are likely to serve as problem-dependent trainable components of hybrid scientific computing workflows rather than universal replacements for traditional numerical solvers.

Problem statement. Traditional UHF-band horn antennas are typically heavy and bulky, which limits their application in systems with strict size and mass constraints. The transformation of solid metal antennas into wire-grid (WG) and sparse wire-grid structures has been shown to effectively reduce mass and wind load, but practical verification of the optimal current grid approximation (OCGA) methodology and its modifications for generating such structures remains insufficient. Aim. To summarize recently published and new results to provide a general OCGA-based methodology and to experimentally verify this methodology with different grid element elimination tolerances (GEET) to generate actual sparse WG horn antenna structures in the UHF band. Results. A pyramidal horn antenna operating in the UHF band was used to validate the proposed methodology. Various sparse WG structures were fabricated with GEET=5, 10, 25, 40% using OCGA and its modification. The experimental results showed strong agreement between the sparse and original WG structures in terms of reflection coefficient, gain, and radiation patterns. The generated sparse WG antennas demonstrated a mass reduction by 1.04–1.41 times relative to the original WG design and by 6.70–9.23 times relative to the solid structure, while maintaining acceptable performance. The wind load acting on the sparse WG structures was also reduced by 1.02–1.45 times compared with the WG antenna and by 5.25–7.45 times compared with the solid one. Practical significance. The proposed methodology enables the design and fabrication of lightweight, low-cost, and weather-resistant horn antennas without significant degradation of antenna performance. The results can be applied to various types of antennas and scatterers operating in different frequency bands, making the approach suitable for modern satellite, radar, and telecommunication systems where mass and structural resistance are critical.

In this letter, the solid structure of a UHF-band horn antenna is transformed into a sparse wire-grid structure. The novelty of this work is that for the first time the actual sparse wire-grid structure was generated by applying Optimal Current Grid Approximation and its modifications to the original wire-grid structure. We present the antenna design details and experimental measurements of the antenna characteristics for these wire-grid structures. Comparative analysis of the antenna characteristics obtained by simulation and experiment shows that the original and sparse wire-grid structures are in good agreement with each other and with the solid structure. The generated sparse wire-grid structure is by 1.41 times less heavy than the original wire-grid structure and by 9.23 times - than the solid structure. The results of this work demonstrate the effectiveness of Optimal Current Grid Approximation and its modifications in generating sparse wire-grid structures with significantly less mass than the original wire-grid structures, as well as solid structures while maintaining the antenna performance.

Wide use of radioelectronic systems requires more complex antennas. Determining the location of the excitation source (feed) in a complex antenna structure plays an important role and depends on many factors. Currently, this choice is often made based on the designer experience and requires careful modeling and analysis. One of the popular methods used in such programs is the characteristic mode analysis (CMA). However, previous CMA-based studies that determine the source location often considered the excitation of low-order modes. In this paper, we present an algorithm to determine the optimal source location in a wire grid antenna that excites all modes reasonably well. This algorithm is based on the product of characteristic current and modal significance to obtain the maximum possible current distribution along the an-tenna wires and radiation field. The proposed algorithm is tested here on the example of dipole and conical spiral structures in the frequency ranges of 0.1–1 GHz and 9–11 GHz, respectively, and verified by the method of moments.

The reduction in mass and surface of antennas and scattering structures is an important task in designing electromagnetic devices. To solve this task, we present a novel algorithm based on the optimal current grid approximation for generating sparse scattering structures and evaluating their effectiveness. The main contributions of the work include analyzing the performance of the optimal current grid approximation and its modifications in generating sparse antennas, as well as demonstrating the effectiveness of the algorithm in generating sparse scattering structures using a scattering plate and corner reflectors as an example. To validate the accuracy of the algorithm, we compared the scattering properties of the obtained sparse scattering structures. The results show that the algorithm worked accurately and effectively in generating sparse scattering structures while reducing their mass and surface.

The rapid advancement of telecommunication systems demands antennas with reduced mass and size. Wire-grid structures serve as effective alternatives to traditional solid metal antennas by significantly reducing their mass. The Optimal Current Grid Approximation recently proposed approach has introduced sparse wire-grid structures with further mass reduction but poses fabrication challenges, prompting modified approaches. However, the previously proposed modified approaches only focused on overcoming the difficulties in fabrication, without considering the current distribution, resulting in structures with characteristics different from those of the original wire-grid structure. To overcome these limitations, we propose the “Maximum Current-based” Optimal Current Grid Approximation, a novel approach that selectively reconnects wires with maximum current, improving the radiation performance of the sparse structure and aligning antenna characteristics more closely to those of the original wire-grid structure. Applied to a UHF-horn antenna, the sparse structures generated using the proposed approach were analyzed and their antenna characteristics were compared with those of the sparse structures obtained using other approaches and the original wire-grid structure, which in turn were compared with those from previous studies obtained numerically by different methods and experimentally for solid antenna prototypes. The performed comparative analysis confirmed that the proposed approach generates sparse wire-grid structures with antenna characteristics closer to those of the original wire-grid than other approaches, demonstrating its effectiveness. In addition, based on the simulation results, the sparse wire-grid structure is generated to verify the effectiveness of the proposed approach. The obtained experimental results demonstrate the effectiveness of the proposed approach in generating sparse wire-grid antenna with mass 1.41 times less than the original wire-grid antenna and 7.63 times less than the solid antenna while maintaining the required characteristics.

The reduction of mass and surface of antennas and scattering structures is an important task in designing electromagnetic devices. To solve this task, we present a novel algorithm based on the optimal current grid approximation (OCGA) for generating sparse scattering structures and evaluating their effectiveness. The main contributions of the work include analyzing the performance of the OCGA and its modifications in generating sparse antennas, as well as demonstrating the effectiveness of the algorithm in generating sparse scattering structures using a scattering plate as an example. To validate the accuracy of the algorithm, we compared the scattering properties of the obtained sparse scattering structures. The results show that the algorithm worked accurately and effectively in generating sparse scattering structures while reducing their mass and surface.

Сравнение измеренных частотных характеристик печатных плат с модальным резервированием до и после отказа при разных температурах

This paper focuses on antenna modeling using wire-grid and surface triangulation as two of the most commonly used MoM-based approaches in this field. A comprehensive overview is provided for each of them, including their history, applications, and limitations. The mathematical background of these approaches is briefly presented. Two working algorithms were developed and described in detail, along with their implementations using acceleration techniques. The wire-grid-based algorithm enables modeling of arbitrary antenna solid structures using their equivalent grid of wires according to a specific modeling recommendation proposed in earlier work. On the other hand, the surface triangulation-based algorithm enables calculation of antenna characteristics using a novel excitation source model. Additionally, a new mesh generator based on the combined use of the considered algorithms is developed. These algorithms were used to estimate the characteristics of several antenna types with different levels of complexity. The algorithms computational complexities were also obtained. The results obtained using these algorithms were compared with those obtained using the finite difference time domain numerical method, as well as those calculated analytically and measured. The analysis and comparisons were performed on the example of a rectangle spiral, a spiral, rounded bow-tie planar antennas, biconical, and horn antennas. Furthermore, the validity of the proposed algorithms is verified using the Monte Carlo methodology.