Nonlinear Measurements of a Microwave Time-Varying Load

When a high power microwave load is changing in time due to either microwave heating effect, or an environmental weathering effect, or a manual tuning of the load at high power level, or a manual sweeping of microwave power, the changing complex impedance (both magnitude and phase) is generally very difficult to monitored in real time. This paper reports an experimental result of the real-time nonlinear measurements of a standard time varying load operated at medium high power levels. The technique used is a well developed three-probe automatic impedance tracking measurement system. The real time nonlinear measurement capacity of the system is seen to be excellent. The error of measurements when the power level is changed while the load is kept constant is estimated to be within a few percents.