Dielectric-filled 1 to 18 ghz coaxial slotted line

Abstract

The slotted line has, for a number of years, been one of the most useful and necessary tools in RF and microwave measurements. It was therefore felt appropriate to attempt to design an improved version, capable of broad band operation (1 to 18 GHz) with the ability of examining modulated and unmodulated wave forms. Initially, the relevant transmission line theory was reviewed with particular emphasis placed on the concepts that were to influence the actual design. The unique feature of the project, was the use of semi-rigid cable, which greatly contributed to the realisation of the two main objectives, namely low cost and accuracy. The mechanical construction proved as important as the electrical design and for this reason both topics were analysed and discussed in some detail in the text of the thesis. The approach was justified in that on the final examination, the slotted line performed satisfactorily in comparison to more expensively purchased units, over the expected frequency range without exhibiting an anomalous behaviour. Recommendations that would improve the slotted line even further were made in the Conclusions chapter, with specific attention paid to the redesigning of the probe and the tuning mechanism.