Masters Theses

Abstract

"The history of the multi-section quarter-wave transformer is traced from its beginnings with lumped-element ladder networks in the l 930's. Starting with the geometric mean formula from quarter-wave transformer theory, and insisting on small reflections at the input, a formula is developed for choosing the step impedances of a multi-section quarter-wave transformer. Bandwidth and ripple of a multi-section quarter-wave transformer frequency response are investigated through computer simulation of transformers designed using this formula and found to be directly related. Bandwidth is found to be directly related to the number of sections, and inversely related to the relative mismatch which the transformer must overcome. Ripple is found to be directly related to both the number of steps and the relative mismatch. A sensitivity analysis is done to simulate errors in the fabrication of a three-section transformer in microstrip. Both three-section and four-section transformers are designed, using the formula developed, and constructed for a frequency of 2 GHz using low-loss microstrip substrate. Fabrication errors cause the measured responses of these transformers to differ from their design responses. The experimental responses are predicted through computer simulation using actual measured step widths. These predicted responses agree with the measured responses. The frequency response of the microwave chip resistor used to terminate the experimental transformers is investigated. The importance of good impedance matching in microwave testing is pointed out with a graphic example"--Abstract, p. iii

Advisor(s)

Stanley V. Marshall

Committee Member(s)

Edward A. Wilson
Lee J. Bain

Department(s)

Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Spring 1990

Pagination

xi, 93 pages

Note about bibliography

Includes bibliographical references (pages 91-92)

Rights

© 1990 Alan Richard Webber, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 6039

Print OCLC #

22448914

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