Chan, Auc Fai (2006) The finite difference time domain method for computational electromagnetics. [USQ Project]

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Abstract
Three computer programs are presented in this dissertation. The first one is a onedimensional
(1D) program, simulating a sinusoidal signal propagating along the xaxis.
The second one is a twodimensional (2D) program, simulating radiation from a
narrow slit. The third one is also a 2D program, which is a simulation of a Time
Domain Reflectometer (TDR) probe.
A graphical user interface (GUI) is included in the 1D program, which makes the
computer program userfriendly. A flowchart with details is included in the
appendices.
When applying FDTD to problems where solution regions are unbounded, difficulty
arises. Since no computers can store unlimited amount of data, it is necessary to
somehow, limit the solution regions. Mur’s firstorder absorbing boundary condition
(ABC) is a method to achieve this. The derivation of Mur’s ABC is given in details in
Chapter Four, and implemented in the 1D program. This program serves as an
introduction to FDTD.
The 2D program simulating radiation from a narrow slit has two interesting aspects.
The perfectly matched layer (PML) is expected to absorb all electromagnetic (EM)
waves. No EM waves are supposed to pass through a perfect electric conductor
(PEC). Surprisingly, EM waves do penerate through the connecting points between
PEC and PML. The reason and solution for this ‘leakage’ are given in this
dissertation. Also one might find it a bit confusing to observe that in this program, the
xcomponent of electric field seems to be propagating along the ydirection. The
clarification is given in this dissertation.
TDR can be used to measure the amount of moisture in soil. In the TDR program, it is
required to simulate a 2D model of a TDR probe of given geometry, and to specify
the time constant of a raised cosine function. A plane wave using the raised cosine
function is then introduced into the TDR probe.
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Item Type:  USQ Project 

Refereed:  No 
Item Status:  Live Archive 
Faculty / Department / School:  Historic  Faculty of Engineering and Surveying  Department of Electrical, Electronic and Computer Engineering 
Date Deposited:  11 Oct 2007 01:05 
Last Modified:  02 Jul 2013 22:44 
Uncontrolled Keywords:  1D, 2D, time domain reflectometer (TDR); graphical user interface (GUI); perfectly matched layer (PML); computational electromagnetic; finite difference time domain (FDTD); finite element method (FEM); perfect electric conductor (PEC) 
Fields of Research :  08 Information and Computing Sciences > 0803 Computer Software > 080309 Software Engineering 09 Engineering > 0906 Electrical and Electronic Engineering > 090699 Electrical and Electronic Engineering not elsewhere classified 
URI:  http://eprints.usq.edu.au/id/eprint/2404 
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