On peculiarities of S-parameter measurements

Measured S-parameters are a key factor in many measurement and/or modeling applications. Experience teaches that quantities that are derived from the measurements can contain spikes, and that they tend to grow with connection imperfections. In this paper, a possible theory is provided and the presence of the peaks is shown in practical measurements. The measured propagation constant (/spl gamma/((/spl omega/)) and characteristic impedance (Z/sub 0/(/spl omega/)) of a transmission line are used as an illustrative example.