Type of Document	Dissertation
Author	Fidanboylu, Kemal M.
URN	etd-08082007-120136
Title	Time domain synthesis applied to modeling of microwave structures and material characterization
Degree	PhD
Department	Electrical Engineering
Advisory Committee	Advisor Name Title Riad, Sedki Mohamed Committee Chair Besieris, Ioannis M. Committee Member Elshabini-Riad, Aicha A. Committee Member Herdman, Terry L. Committee Member Vanlandingham, Hugh F. Committee Member
Keywords	Microwave devices
Date of Defense	1991-05-15
Availability	restricted
Abstract In this dissertation a new time domain approach for the determination of material properties such as the complex permittivity and the complex permeability in a stripline geometry is presented. The new technique uses both Time Domain Reflectometry (TDR) and Time Domain Transmission (TDT) measurements for determining an optimum frequency dependent lossy transmission line model for the stripline under test. The optimization is done in the time domain by comparing the experimental TDR and TDT response waveforms with the simulated ones using a non-linear least squares fit. The conventional optimization algorithms have shown to be inefficient in this specific application. In this dissertation an efficient optimization algorithm which has been developed to suit this application is also presented. In general, the material properties in a stripline under test are related with the geometrical parameters of the line through complicated integral expressions. Using the proposed approach, the use of complicated integral expressions are avoided. The material properties such as the complex permittivity and the complex permeability are determined from the optimum lossy transmission line model. For this purpose, the frequency behavior of the line parameters have to be known beforehand in the form of causal mathematical models. The literature survey shows that, no causal model exists for the complex permittivity of thick film and polymer materials. The dissertation proposes a new causal model for this purpose.
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