ASYMPTOTIC METHODS OF ANALYSIS IN ELECTRODYNAMICS

Author(s):  
И.А. Баранников ◽  
К.А. Бердников ◽  
Е.А. Ищенко ◽  
С.М. Фёдоров

Рассматривается метод геометрической дифракции и физической оптики, который является одним из самых точных и эффективных для решения крупных электродинамических задач. Для анализа характеристик процесса приводится его математическое описание, а также для сравнения с ним приведено описание метода конечного интегрирования, который является наиболее популярным и эффективным для малых объектов. Так показано, что применение метода МКИ невозможно для крупных объектов, так как в процессе сеточного разбиения происходит создание слишком большого числа ячеек для расчета, что значительно усложняет процедуру анализа. Для оценки эффективности и точности метода было произведено моделирование антенного элемента, который установлен на корабле-носителе. Так, характеристики излучателя рассчитывались с использованием метода конечного интегрирования, после чего характеристики диаграмм направленности передавались в проект с кораблем, затем производилось моделирование с использованием метода SBR. Итоговые результаты моделирования показали высокую эффективность и точность метода, а возможность установки шага сканирования позволяет управлять временем моделирования, однако стоит учитывать, что слишком большой шаг приводит к снижению точности анализа The article discusses the method of geometric diffraction and physical optics, which is one of the most accurate and effective for solving large electrodynamic problems. To analyze the characteristics of the process, we give its mathematical description and, for comparison, a description of the final integration method, which is the most popular and effective for small objects. Thus, we show that the application of the MCI method is impossible for large objects since in the process of grid division, too many cells are created for the calculation, which significantly complicates the analysis procedure. To assess the effectiveness and accuracy of the method, we simulated the antenna element, which is installed on the carrier ship. We calculated the characteristics of the emitter using the method of finite integration, after which we transferred the characteristics of the radiation patterns to the project with the ship, then we carried out the simulation using the SBR method. The final results of modeling showed high efficiency and accuracy of the method, and the ability to set the scanning step allows you to control the simulation time, however, it should be borne in mind that too large a step leads to a decrease in the accuracy of the analysis.

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Mohammad Asif Zaman ◽  
Md. Abdul Matin

A physical optics based method is presented for calculation of monostatic Radar Cross-Section (RCS) of a shell-shaped projectile. The projectile is modeled using differential geometry. The paper presents a detailed analysis procedure for RCS formulation using physical optics (PO) method. The shortcomings of the PO method in predicting accurate surface current density near the shadow boundaries are highlighted. A Fourier transform-based filtering method is proposed to remove the discontinuities in the approximated surface current density. The modified current density is used to formulate the scattered field and RCS. Numerical results are presented comparing the proposed method with conventional PO method. The results are also compared with published results of similar objects and found to be in good agreement.


2000 ◽  
Vol 7 (4) ◽  
pp. 209-216 ◽  
Author(s):  
J.H. Lin ◽  
D.K. Sun ◽  
W.X. Zhong ◽  
W.S. Zhang

For structures subjected to stationary or evolutionary white/colored random noise, their various response variances satisfy algebraic or differential Lyapunov equations. The solution of these Lyapunov equations used to be very difficult. A precise integration method is proposed in the present paper, which solves such Lyapunov equations accurately and very efficiently.


Author(s):  
I. F. Kupryashkin ◽  
K. Yu. Zavodskyh

Introduction. Computer-aided design systems for microwave devices are an effective tool for assessing the backscattering characteristics of complex-shaped objects. However, these calculations are often associated with significant computational costs, especially at large values of the ratio of the characteristic dimensions of the object to the wavelength. The use of asymptotic methods in combination with the mesh coarsening of object partition can significantly reduce these costs. However, in each practical case, this leads to a deterioration in the accuracy of the estimates obtained, which is hard to predict.Aim. Comparative assessment of the results of modeling the scattering field in the CAD of microwave devices using various methods for calculating and detailing the object model in the decimeter and centimeter wavelength ranges.Materials and methods. The research object was an anti-tank guided missile FGM-148 Javelin. The scattering field of Altair FEKO microwave devices was modeled in CAD using the methods of moments and physical optics in the frequency range from 1 to 10 GHz and angles from 0 to 180°. A comparison of one-dimensional backscatter diagrams and radar images obtained using these methods was carried out.Results. For the class of objects under consideration, the method of physical optics provides acceptable accuracy at frequencies of 5 GHz and higher with a step of partitioning the model surface of the order of one centimeter and a total calculation duration of the order of several minutes (Intel Core i5-4460 PC / 3.2 GHz / 8 MB RAM). At lower frequencies, acceptable accuracy and a similar calculation duration are achieved when calculating by the method of moments and a partitioning step of about 20 cm. The possibility of using the Altair FEKO CAD system for modeling radar images of objects with a resolution of at least 20 cm is demonstrated.Conclusion. The results obtained complement the well-known studies in the field of comparative assessment of the time and accuracy characteristics of various methods for calculating the scattering field of objects in the CAD of microwave devices.


2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Guang Sun ◽  
Yi Liu ◽  
Taolin Liu ◽  
Hu Yang

In this paper, a compact, wideband, and high-efficiency substrate integrated waveguide (SIW) feeding cavity-backed aperture-coupled magneto-electric (ME) dipole antenna element and its array are proposed. Firstly, an SIW cavity-backed and a modified bowtie dipole are designed for the antenna element which makes it possess a high gain and wide impedance bandwidth. The antenna element covers an impedance bandwidth of 66.3% from 10.7 to 21.3 GHz with a peak gain of 10.3 dBi. Secondly, a 4 × 4 array is designed using the proposed antenna element. And a full-corporate substrate integrated waveguide feeding network is introduced to excite the array elements for the antenna application with wide bandwidth and high efficiency. For validation, a prototype of 4 × 4 array is fabricated by standard printed circuit board (PCB) facilities and further measured. The measured −10 dB impedance bandwidth of the proposed 4 × 4 antenna array is 30% (12.75–17.25 GHz) with its gain being 18.2–20.9 dBi within the entire band. The measured maximum aperture efficiency of the antenna array is 94% at 14.92 GHz. Notably, the measured results agree well with simulations, and it shows great advantages over other similar antennas on efficiency and bandwidth.


2020 ◽  
Vol 68 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Oleg A. Iupikov ◽  
William Hallberg ◽  
Rob Maaskant ◽  
Christian Fager ◽  
Robert Rehammar ◽  
...  

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