Structure decomposition technique and impedance matrix interpolation for efficient broad band analysis by method of moments

2007 ◽  
Author(s):  
M. Surma ◽  
D. Wojcik
Keyword(s):  
Method Of Moments ◽  
Broad Band ◽  
Impedance Matrix ◽  
Decomposition Technique ◽  
Structure Decomposition ◽  
Matrix Interpolation

Improved MoM-PO-Based Technique for Wideband Analysis of Antennas around Large Platforms

2012 ◽  
Vol 629 ◽  
pp. 646-648
Author(s):  
Ji Ma ◽  
Shu Xi Gong ◽  
Qian Wang
Keyword(s):  
Frequency Response ◽  
Method Of Moments ◽  
Hybrid Method ◽  
Wide Band ◽  
Numerical Results ◽  
Physical Optics ◽  
Impedance Matrix ◽  
Mutual Impedance ◽  
Interpolation Technique ◽  
Matrix Interpolation

An improved wide-band analysis which combines the hybrid method of moments-physical optics (MoM-PO) formula with impedance matrix interpolation technique for antennas around large platforms is presented. The algorithm proposed in this paper interpolated the mutual impedance matrix between MoM and PO regions rather than the MoM self-matrix. This practice can result in more accurate frequency response than the conventional approach. Sample numerical results demonstrate the capability of the algorithm.

scholarly journals Combination of MLFMA and ACA to Accelerate Computation of Scattering from Underground Targets

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Zhiwei Liu ◽  
Dan Tang ◽  
Zhanyang Zhang ◽  
Yueyuan Zhang ◽  
Xiaoli Wang ◽  
...  
Keyword(s):  
Integral Equation ◽  
Nondestructive Evaluation ◽  
Method Of Moments ◽  
Impedance Matrix ◽  
Computation Complexity ◽  
Surface Integral ◽  
Efficient Simulation ◽  
Urban Construction ◽  
Multilevel Fast Multipole Algorithm ◽  
Fast Multipole Algorithm

Electromagnetic nondestructive evaluation of underground targets is of great significance for the safety of urban construction. Based on the accurate and efficient simulation of scattering, we can detect the underground targets successfully. As one of the most popular numerical methods in electromagnetics, surface integral equations solved by method of moments (MoM) are used to simulate the scattering from underground targets in this paper. The integral equation is discretized by RWG basis and Galerkin testing. Multilevel fast multipole algorithm (MLFMA) is used to decrease the computation complexity and memory cost. However, the octree used in MLFMA is not applied for rough surfaces and targets together; both the surface and target need to construct octree separately. Since the combination of MLFMA and ACA can build a more efficient method to compute scattering from underground targets, adaptive cross approximation (ACA) is used to compress the impedance matrix instead of MLFMA for the coupling action between the rough surface and target. That is to say that, when calculating the scattering of two targets, target self-interaction is suitable for MLFMA calculation and the coupling between targets is approximated by ACA. Numerical results demonstrate the accuracy and efficiency of our proposed method.

scholarly journals Comparison of Wavelet Packet and Wavelet in Solving Arbitrary Array of Parallel Wires Integral Equations in Electromagnetics

2020 ◽  
Vol 9 (3) ◽  
pp. 8-14
Author(s):  
M. Bayjja ◽  
G. Alsharahi ◽  
M. Aghoutane ◽  
N. A. Touhami
Keyword(s):  
Integral Equation ◽  
Method Of Moments ◽  
Direct Method ◽  
Wavelet Packet ◽  
Dense Matrix ◽  
Impedance Matrix ◽  
Electric Field Integral Equation ◽  
Electromagnetic Problems ◽  
Number Of Zeros ◽  
Wavelet Packet Transformation

In this paper, wavelets transformation (WT) and wavelet packet transformation (WPT) are used in solving, by the method of moments, a semicircular array of parallel wires electric field integral equation.  First, the integral equation is solved by applying the direct method of moments via point-matching procedure, results in a linear system with a dense matrix.  Therefore, wavelet transformation and wavelet packet transformation are used to sparsify the impedance matrix, using two categories of wavelets functions, Biorthogonal (bior2.2) and Orthogonal (db4) wavelets.  The far-field scattering patterns and the comparison between wavelets transformation and wavelet packet transformation in term number of zeros in impedance matrix and CPU Time reduction are presented. Numerical results are presented to identify which technique is best suited to solve such scattering electromagnetic problems and compared with published results.

scholarly journals Dynamic RCS Estimation according to Drone Movement Using the MoM and Far-Field Approximation

2021 ◽  
Vol 21 (4) ◽  
pp. 322-328
Author(s):  
Dong-Yeob Lee ◽  
Jae-In Lee ◽  
Dong-Wook Seo
Keyword(s):  
Fourier Transform ◽  
Cross Section ◽  
Method Of Moments ◽  
Iterative Process ◽  
Rotation Angle ◽  
Field Approximation ◽  
Far Field ◽  
Impedance Matrix ◽  
The Matrix ◽  
The Fourier Transform

Micro-Doppler signatures from the rotating propellers of a drone can be utilized to distinguish the drone from clutter or airborne organisms with similar radar cross section (RCS) levels, such as birds and bats. To obtain the micro-Doppler signatures of a drone, calculation or measurement of the electric field scattered from the rotating propellers is essential. In this paper, using the relative angle concept and far-field approximation, we propose a way to rapidly estimate the dynamic RCS of a drone with several propellers according to its movement. In addition, based on the fact that the shape of the propeller does not change even if it rotates, we construct an impedance matrix only once and apply the matrix to the method of moments instead of the iterative process of calculating the impedance matrix and inverse matrix for each rotation angle of the propeller. Finally, by using the Fourier transform of the results from the proposed method, the rotation frequencies of the propellers according to the movement of the drone can be obtained.

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