VANA evaluation via a multi-state termination

In a series of former papers, a number of applications for a multi-state termination in the microwave range were described. This paper will consider the application to the accuracy evaluation of a vector automatic network analyzer (VANA) in greater detail, and give experimental results. The technique was applied to a commercially available VANA and, over the frequency range of 2-18 GHz yielded the following results. In a simulated measurement application, the projected measurement errors were mostly below 0.001 in the magnitude of the unknown /spl Gamma/, although occasional errors of a half percent were also noted. In one case, however, errors as large as 10% were observed which indicated a serious but intermittent malfunction of the VANA. It was also possible to demonstrate the general stability of the multi-state termination and also to recognize a small instability in one of its states.