Analysis and design of conical transmission line power combiners

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dc.contributor.advisor Meyer, P.
dc.contributor.advisor Van der Walt, P. W. De Villiers, Dirk I.L. en_ZA
dc.contributor.other University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. 2008-02-19T07:58:15Z en_ZA 2010-06-01T08:20:34Z 2008-02-19T07:58:15Z en_ZA 2010-06-01T08:20:34Z 2007-12 en_ZA
dc.description Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2007.
dc.description.abstract This dissertation presents a technique for the design of N-way conical line power combiners, which offers significant advantages over existing axially symmetric combining techniques. A full analytical study of conical transmission lines is done, and evaluated results are presented. These include a proof of the cutoff frequency equation, and plots of the field patterns, of higher order modes which are unavailable in literature. A coaxial fed conical line combiner for 10 inputs is proposed, designed and evaluated. The design technique relies on the uniform transmission line characteristics of the conical lines to eliminate the need for complex full wave optimisation, typically needed in the design of the more commonly used radial line combiners. Circuit models are instead employed to achieve a wide matched bandwidth by using optimised stepped impedance coaxial lines to feed the combining structure. The prototype developed at X-band displays more than an octave bandwidth with a return loss of better than -14.5 dB. Using tapered line matching sections increases the power handling capability of the combiner by eliminating sharp edges, and allows for tolerance insensitive manufacture of the structure by widening conductor spacings. Such a 10-way prototype is developed at X-band which displays a -18.7 dB return loss bandwidth of 47% with very low losses. A study is done to determine the limitations on the design of general N-way combiners, and the results are incorporated into the design technique. The full process is demonstrated by the design and simulation of a 30-way combiner at Ku-band which displays a simulated -20 dB return loss bandwidth of 34%. The design technique is simple to execute and requires very little full wave analysis. Results obtained with the manufactured combiners are better than those of any previously published axially symmetric combiners. en_ZA
dc.format.extent 6383629 bytes en_ZA
dc.format.mimetype application/pdf en_ZA
dc.language.iso en en_ZA
dc.publisher Stellenbosch : University of Stellenbosch
dc.subject Combiners en_ZA
dc.subject Radial combiners en_ZA
dc.subject Conical combiners en_ZA
dc.subject Conical transmission tines, en_ZA
dc.subject N-way combiners en_ZA
dc.subject Dissertations -- Electrical and electronic engineering en
dc.subject Theses -- Electrical and electronic engineering en
dc.title Analysis and design of conical transmission line power combiners en_ZA
dc.type Thesis en_ZA
dc.rights.holder University of Stellenbosch
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