Recent advances in the design of precision coaxial standards and components

Significant advances in precision coaxial standards and components have come with the introduction of precision coaxial connectors and the development of highly accurate impedance-measuring techniques. These advances include dielectric supports with extremely small interface discontinuities, contacting members that are insensitive to mechanical tolerances, calculable air-line impedance standards of very high absolute accuracy, reference impedance terminations that retain their nominal dc values to very high frequencies, smooth diametral transitions that are essentially free of local disturbances, and a novel impedance-matching tuner. The theory, design and applications of the advances outlined are the subject of this paper.