Large-signal characterization of millimeter-wave transistors using an active load-pull measurement system

An automated measurement system is described for obtaining the load-pull characteristics of high-speed transistors at millimeter-wave frequencies. The method uses 'active tuning' to vary the transistor output load impedance electronically. the large-scale characteristics of an 8-by-20- mu m permeable base transistor (PBT) have been measured with this method and applied to the design of 27-mW PBT amplifier at 40.1 GHz.<>