High-efficiency X-band GaInP/GaAs HBT MMIC power amplifier for stable long pulse and CW operation

We report on the design and fabrication of high-efficiency monolithic X-band power amplifiers using a well optimized GaInP/GaAs heterojunction bipolar transistor (HBT) technology. Ballast resistors have been introduced to each emitter finger to avoid completely the current collapse effect and thus enabling long pulse and continuous wave (CW) operation. The amplifiers are designed for operation at moderate current densities to reduce junction temperature and to improve reliability. State-of-the-art performances with maximum output powers of 9 W with a power-added efficiency (PAE) of 42 % and peak power-added efficiencies of 45 % have been achieved at 10 GHz under critical long pulse conditions (pulse width=100 /spl mu/s, duty cycle=10 %). To our knowledge these results represent the best performance of any GaInP/GaAs HBT MMIC power amplifier considering efficiency, output power, operation frequency, and pulse conditions.