City Research Online

Abstract

The properties of coupled microstrip lines are investigated with the aim of improving the performance of microstrip proximity directional couplers. A closely related transmission line structure termed, for convenience, a microstrip/slot line combination, is also investigated. This supports two dominant modes, easily made degenerate by the addition of a second lowloss high dielectric material. ‘the investigation is followed by the construction of an experimental 3 dB coupler, based upon the microstrip/slot line structure.

Ring resonators are used to measure the normalised guide wavelengths of the modes of the transmission line structures. For coupled microstrip lines the dispersions of the even- and odd~modes are shown to be approximately linear between 1 and 12 GHz, and well characterised by recent theoretical analyses. The normalised guide wavelengths of the dominant modes of the microstrip/slot line combination are also measured using ring resonators.

A new method of measuring the characteristic impedance of transmission lines is presented, and has been used to measure the frequency dependence of the characteristic impedance of microstrip limes. he characteristic impedances of the dominant modes of the microstrip/slot line combination are also determined.

The theoretical analysis of the microstrip transmission line is also studied with attention on the ability and ease at which available methods could analyse the more complex microstrip/slot line combination. The recent Least Square technique applied to mode matching solutions is tested on L-shaped waveguides and ‘then applied to the microstrip problem in a way more general than was previously carried out. {E, in addition to M solutions are given for the L-shaped waveguide.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments:	School of Policy & Global Affairs > Department of Sociology & Criminology School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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