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A SuperNEC implementation of model besed parameter estimation by interpolating the method of moments impedance matrix

SuperNEC is a method of moments (MoM) electromagnetic eld solver based on the Numerical
Electromagnetics Code (NEC). Much of the simulation time can be attributed to
the lling of the impedance matrix, which is performed at each frequency point of interest.
Impedance matrix interpolation methods have been implemented in SuperNEC to reduce
the computational time required to ll the impedance matrix [Z]. Elements in [Z] vary predictably
over frequency and can be approximated by a second order polynomial. A second
improved method is implemented where the dominant frequency variation term is removed
prior to calculating the tting function. A method of determining the optimum sample range
relative to simulation range and maximum interaction distance has been developed. Given
the correct choice of sample range the mean error in the MoM solution is less than 10% over
the frequency range and the input impedance can be reproduced with good agreement over
a wide bandwith. Improvement in the simulation e ciency of 1.7 times can be expected if
su cient frequency points are of interest to account for the computational time required to
sample the matrix and determine tting function coe cients. This method has been applied
to a dipole antenna, an LPDA and a horn antenna. To increase the simulation bandwidth
and retain an acceptable level of accuracy, the bandwidth is split into multiple sub-bands.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/5877
Date09 December 2008
CreatorsO'Leary, Neil Iain
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Formatapplication/pdf, application/pdf

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