A Four-Port Automatic Network Analyzer

A four-port automatic network analyzer has been built for the 8-12 GHz range. An essential feature of this analyzer [1] compared with the six-port systems [2-3] is that only one detector is used, and an electrically adjustable short circuit is added as a reference object. A computer program has been developed which is written in Basic for a small desk-top computer (HP 85) to handle measurement data, adjust the short circuit and present the results. Calibration can be done automatically once for all. Measurements over the range of 8-12 GHz, including presentation, can be done in about half a minute. Results within 1 percent of magnitude and 2 degrees of phase are demonstrated.