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Title: Application of computer-aided design to microstrip circuits
Author: Hosseini, N. M.
ISNI:       0000 0001 3582 1181
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1977
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The work is based on a facility which has been developed in the Department of Engineering and presently is concerned with computer correction » optimization and computer-aided design of microwave Integrated circuits. The characterization of distributed elements on microstrip, particularly for use with a computer analysis/optimization package present a considerable challenge, making the analysis of microwave circuits difficult. Here, the network analyzer, in conjunction with automatic computer corrected S-parameter measurement, is utilized to characterize the discontinuity in terms of its properties at the external terminals. Some empirical expressions have been obtained for the effects of abrupt change in centre conductors of microstrip lines. The generally accepted numerical techniques for evaluating microstrip parameters In conjunction with the computer-aided design packages are no longer useful. The reason for this is that a numerical routine has to be called upon numerous times, which makes it impossible in an optimization program. This was initially overcome by developing an algorithm, which allows for the evaluation of conductor and dielectric losses, as well as dispersion effects. While the use of good analysis programs were essential, the limited capabilities associated with fast analysis algorithms often significantly reduce the efficiency of the design procedure. An algorithm was then developed to evaluate the two-port parameters of a multi-terminal circuit , which halves the number of Iterations In comparison with conventional -nodal analysis routines. It was therefore decided to include junction parasitics and the above parameters in the optimization work. First some modifications were made on current optimization methods to be adopted for the design of microwave integrated circuits. Two programs were then developed, one applied to the design of several amplifiers on microstrip, utilizing gallium arsenide F.E.T.'s as well as bipolar transistors. The other program is used to characterize two-port active as well as passive devices. Initially a preliminary circuit was designed using a unilateral device model. Optimization was used to modify the circuit performance to meet the desired specification, by varying the element values. It was then possible to construct such-an optimized circuit with the confidence that it would perform in a manner close to that which was predicted.
Supervisor: Not available Sponsor: Science Research Council ; Vizārat-i ʻUlūm, Taḥqīqāt va Fannāvarī, Iran
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General) ; TK Electrical engineering. Electronics Nuclear engineering