A conformal symplectic multi-resolution time-domain method with ADE-PML

2021 ◽  
pp. 1-14
Author(s):  
Guanghua Wu ◽  
Yawen Liu ◽  
Bo Zhang
Keyword(s):  
Cross Section ◽  
Time Domain ◽  
Effective Dielectric Constant ◽  
Resolution Time ◽  
Dielectric Sphere ◽  
Tunnel Model ◽  
Perfect Matched Layer ◽  
Difference Time ◽  
Cross Section Distribution ◽  
Good Agreement

In this paper, the conformal finite-difference time-domain (CFDTD) technique and the concept of effective dielectric constant are applied to symplectic multi-resolution time-domain (SMRTD) algorithm based on Daubechies scaling functions, resulting in a conformal SMRTD (C-SMRTD) method. Moreover, a novel implementation of perfect matched layer with auxiliary differential equation (ADE-PML) is presented for the SMRTD method. Numerical results of the radar cross section (RCS) of a dielectric sphere verify the effectiveness of the C-SMRTD method, which shows good agreement with the results derived by analytical methods. It is also shown that the accuracy of the C-SMRTD method has been significantly improved compared with the MRTD method with step approximation, and the proposed method has an advantage over CFDTD at saving the CPU time and memory. Furthermore, a vault-top tunnel model is established with the proposed method, and the characteristic of the field cross-section distribution of the electromagnetic pulse (EMP) propagation in the tunnel model is also presented and discussed.

Focusing Technique for Holographic Subsurface Radar Based on Image Entropy

2021 ◽  
Vol 36 (4) ◽  
pp. 373-378
Author(s):  
Haewon Jung ◽  
Dal-Jae Yun ◽  
Hoon Kang
Keyword(s):  
Numerical Simulation ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Software Package ◽  
Reconstruction Algorithm ◽  
Simulation Software ◽  
Material Information ◽  
Difference Time ◽  
Actual Depth ◽  
Good Agreement

An image focusing method for holographic subsurface radar (HSR) is proposed herein. HSR is increasingly being utilized to survey objects buried at shallow depths and the acquired signals are converted into an image by a reconstruction algorithm. However, that algorithm requires actual depth and material information or depends on human decisions. In this paper, an entropy-based image focusing technique is proposed and validated by numerical simulation software package based on finite-difference time-domain method and experiment. The resulting images show good agreement with the actual positions and shapes of the targets.

scholarly journals Size Determination of Polystyrene Sub-Microspheres Using Transmission Spectroscopy

2020 ◽  
Vol 10 (15) ◽  
pp. 5232
Author(s):  
Tien Van Nguyen ◽  
Linh The Pham ◽  
Khuyen Xuan Bui ◽  
Lien Ha Thi Nghiem ◽  
Nghia Trong Nguyen ◽  
...  
Keyword(s):  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Simulation ◽  
Transmission Spectra ◽  
Experimental Transmission ◽  
Straightforward Method ◽  
Quartz Substrates ◽  
Difference Time ◽  
Good Agreement

Nano/micro polystyrene (PS) beads have found many applications in different fields spanning from drug delivery, bio-diagnostics, and hybrid plasmonics to advanced photonics. The sizes of the PS beads are an important parameter, especially in plasmonic and photonic experiments. In this work, we demonstrate a quick and straightforward method to estimate the diameters of sub-microspheres (0.2 μm to 0.8 μm) using the transmission spectra of a close-packed monolayer of polystyrene beads on glass or quartz substrates. Experimental transmission spectra of the PS monolayers were verified against finite-difference time-domain (FDTD) simulation and showed good agreement. The effects of the substrates on the transmission spectra and, hence, the accuracy of the method were also studied by simulation, which showed that common transparent substrates only cause minor deviation of the PS bead sizes calculated by the proposed method.

scholarly journals The Alternating Direction Implicit Body of Revolution Multiresolution Time Domain Method with Convolution Perfect Matched Layer

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Chen Yiwang ◽  
Ni Jiazheng ◽  
Liu Yawen ◽  
Dong Xiaohua ◽  
Zhang Pin
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Three Dimension ◽  
Body Of Revolution ◽  
Alternating Direction Implicit ◽  
Alternating Direction ◽  
Perfect Matched Layer ◽  
Difference Time

Overmuch memory and time of CPU have been taken by multiresolution time domain (MRTD) method in three-dimension issues. In order to solve this problem, the alternating direction implicit body of revolution multiresolution time domain (ADI-BOR-MRTD) scheme is presented. Firstly, based on body of revolution finite difference time domain (BOR-FDTD) method, equations of body of revolution multiresolution time domain (BOR-MRTD) method are implemented. Then alternating direction implicit (ADI) is introduced into BOR-MRTD method. Lastly, convolution perfect matched layer (CPML) is applied for ADI-BOR-MRTD method. Numerical results demonstrate that ADI-BOR-MRTD method saves more memory and time of CPU than FDTD and MRTD methods.

scholarly journals A Compact Wideband Stacked Antenna for the Tri-Band GPS Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Maher M. Abd Elrazzak ◽  
M. F. Alsharekh
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Patch Antenna ◽  
Finite Difference Time Domain ◽  
Dielectric Materials ◽  
Scattering Parameters ◽  
High Permittivity ◽  
Perfect Matched Layer ◽  
Difference Time ◽  
Stacked Patch Antenna

A compact wideband stacked patch antenna is presented for the applications of GPS systems. This antenna covers the L1, L2, and L5 GPS bands of operating frequencies 1.575, 1.227, and 1.176 GHz, respectively. High permittivity dielectric materials are used to minimize the antenna dimensions. The obtained antenna is of dimensions  mm. To verify the design, the time dependence field distribution, the scattering parameters, and the radiation pattern are presented. The scattering parameters show that the antenna operates at the GPS frequencies with lower than  dB. The finite difference time domain (FDTM) with the perfect matched layer (PML) is used in the present analysis.

Improvement of the Stability of Convolutional Perfect Matched Layer Based on Finite Difference Time-domain Algorithm

2017 ◽  
Vol 46 (8) ◽  
pp. 826001
Author(s):  
谢国大 XIE Guo-da ◽  
黄志祥 HUANG Zhi-xiang ◽  
王丽华 WANG Li-hua ◽  
吴先良 WU Xian-liang
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Perfect Matched Layer ◽  
The Stability ◽  
Difference Time
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