Computer-Aided Experimental Characterisation of Microstrip-to-Coaxial Transitions

This paper proposes a novel circuit model for microstrip-to-coaxial transitions and describes a versatile computer-aided experimental technique to determine the model parameters. Only one simple test structure is needed: a two-port consisting of a length of uniform microstrip line connected at both ends to a transition of the type to be characterised. The determination of the model parameters is based upon measured values of the transmission coefficient of this two-port. The method is illustrated for a common SMA microstrip launcher.