A 1-watt 10-GHz bipolar transistor

The design parameters of a 1-W 10-GHz X-band silicon bipolar transistor are discussed in relation to the incorporation of state-of-the-art process technology such as electron beam lithography. Transistor design is evaluated in terms of power gain requirement, limitations on saturated power density, and maximum allowable thermal dissipation. The techniques used to combine power in a single package at 10 GHz are outlined. DC characterization data are related to 8, 10, and 12 GHz performance data obtained by using a coaxial tuner specially designed for the task. The demonstration of a 1-W CW at 10 GHz with 4.5 dB gain and 20% power-added efficiency points to many new areas for investigation. With the advances in process technology and circuit techniques, the silicon bipolar transistor is expected to become another important solid-state source in X-band power generation and amplification.