Improvement of Shaped Conductive Backfill Material for Grounding Systems

2021 ◽  
Vol 36 (4) ◽  
pp. 442-449
Author(s):  
Run Xiong ◽  
Qin Yin ◽  
Wen Yang ◽  
Yan Liu ◽  
Jun Li
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Outer Layer ◽  
Finite Difference Time Domain ◽  
Main Body ◽  
Grounding Resistance ◽  
Backfill Material ◽  
In Series ◽  
Fdtd Simulations ◽  
Difference Time

In this paper, some improvements have been proposed for low resistance shaped conductive backfill material (SCBM) based on finite-difference time-domain (FDTD) simulations in grounding systems. It is found SCBM can be produced by conjunction of several layers with conductivity decreasing gradually from inner layer to outer layer, and smooth conductivity reduction between layers would lead to a better grounding performance. It is also found cuboid shape is a much more efficient shape than cube and cylinder shapes for SCBM, and holes can be made on the SCBM’s main body. It suggested to bury SCBM vertically when ground soil permits, otherwise bury SCBM horizontally and deeper burying depth would result in smaller grounding resistance. Results show it is not needed to connect the SCBMs one by one tightly in series SCBM, and some distances is allowed without dramatically increasing grounding resistance.

Finite-Difference Time-Domain Simulation of Microwave Sintering in A Variable-Frequency Multimode Cavity

1996 ◽  
Vol 430 ◽  
Author(s):  
Mikel J White ◽  
Steven F. Dillon ◽  
Magdy F. Iskander ◽  
Hal D. Kimrey
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Microwave Sintering ◽  
Single Frequency ◽  
Frequency Variation ◽  
Variable Frequency ◽  
Frequency Range ◽  
Fdtd Simulations ◽  
Difference Time

AbstractThere have been recent indications that variable-frequency microwave sintering of ceramics provides several advantages over single-frequency sintering, including more uniform heating, particularly for larger samples. The Finite-Difference Time-Domain (FDTD) code at the University of Utah was modified and used to simulate microwave sintering using variable frequencies and was coupled with a heat-transfer code to provide a dynamic simulation of this new microwave sintering process. This paper summarizes results from the FDTD simulations of sintering in a variable-frequency cavity. FDTD simulations were run in 100-MHz steps to account for the frequency variation in the electromagnetic fields in the multimode cavity. It is shown that a variable-frequency system does improve the heating uniformity when the proper frequency range is chosen. Specifically, for a single ceramic sample (4 × 4 × 6 cm3), and for a variable-frequency range from f = 2.5 GHz to f = 3.2 GHz, the temperature distribution pattern was much more uniform than the heating pattern achieved when using a single-frequency sintering system at f = 2.45 GHz.

Quantifying Sub-gridding Errors in Standard and Hybrid Higher Order 2D FDTD Simulations

2021 ◽  
Vol 35 (11) ◽  
pp. 1428-1429
Author(s):  
Madison Le ◽  
Mohammed Hadi ◽  
Atef Elsherbeni
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Contrast Ratio ◽  
Higher Order ◽  
Fdtd Simulation ◽  
Fdtd Simulations ◽  
2D Fdtd ◽  
Difference Time

Sub-gridding errors for a 2D Finite-Difference Time-Domain (FDTD) simulation are compared for both the standard FDTD and Hybrid higher order FDTD cases. Subgridding contrast ratios of 1:3, 1:9, 1:15, and 1:27 are considered and analyzed. A correlation is seen between the increase of contrast ratio with the increase of sub-gridding errors for both standard and hybrid cases. However, a trend of errors reduction when using hybrid formulations over standard formulations is apparent for each contrast ratio.

scholarly journals Finite-Difference Time Domain Techniques Applied to Electromagnetic Wave Interactions with Inhomogeneous Plasma Structures

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Julio L. Nicolini ◽  
José Ricardo Bergmann
Keyword(s):  
Electromagnetic Wave ◽  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Inhomogeneous Plasma ◽  
Computational Cost ◽  
Transient Effects ◽  
Plasma Properties ◽  
Fdtd Simulations ◽  
Difference Time

Motivated by the emerging field of plasma antennas, electromagnetic wave propagation in and scattering by inhomogeneous plasma structures are studied through finite-difference time domain (FDTD) techniques. These techniques have been widely used in the past to study propagation near or through the ionosphere, and their extension to plasma devices such as antenna elements is a natural development. Simulation results in this work are validated with comparisons to solutions obtained by eigenfunction expansion techniques well supported by the literature and are shown to have an excellent agreement. The advantages of using FDTD simulations for this type of investigation are also outlined; in particular, FDTD simulations allow for field solutions to be developed at lower computational cost and greater resolution than equivalent eigenfunction methods for inhomogeneous plasmas and are applicable to arbitrary plasma properties such as spatially or time-varying inhomogeneities and collision frequencies, as well as allowing transient effects to be studied as the field solutions are obtained in the time domain.

Effective Excitation of Superfocusing Surface Plasmons using Phase Controlled Waveguide Modes

2009 ◽  
Vol 1182 ◽  
Author(s):  
Kazuhiro Yamamoto ◽  
Kazuyoshi Kurihara ◽  
Junichi Takahara ◽  
Akira Otomo
Keyword(s):  
Numerical Analysis ◽  
Finite Difference ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Practical Method ◽  
Dielectric Waveguides ◽  
Waveguide Modes ◽  
Fdtd Simulations ◽  
Difference Time ◽  
Effective Excitation

AbstractWe propose more practical method to realize the superfocusing modes based on waveguide structures, and present a numerical analysis these structures using the finite-difference time-domain (FDTD) simulations. For metallic wedged structure coupled to dielectric waveguides, we investigate a method of controlling superfocusing by changing the phase of waveguide modes.

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