Calibrating a Six-Port Reflectometer Using Three Known Loads

A technique for calibrating an arbitrary six-port network using nine unknown loads and three known loads is described. The technique is similar to the self-calibration technique first developed by Engen. However, it uses full six-port to four-port reduction so that it is quite insensitive to errors, The theory is illustrated with typical measurement results showing an accuracy of better than 1.0% achievable without optimization of the six-port to four-port reduction constants.