A six-port network analyzer load-pull system for active load tuning

An experimental six-port network analyzer has been used as a load-pull system in an active load tuning configuration. It is shown that by using a dual six-port reflectometer and an appropriate calibration procedure, it is possible to measure at the same reference plane the ratio between the incident and reflected waves and the power flow at the output of the test transistor. Using these two values the simulated load impedance seen by a transistor and the microwave power delivered to the simulated load are calculated. Experimental results on microwave transistor characterization confirm the validity of this method. This technique uses less hardware than conventional methods, and presents a comparable accuracy to conventional techniques