An 890 mW stacked power amplifier using SiGe HBTs for X-band multifunctional chips

This paper presents a stacked power amplifier (PA) for X-band multifunctional chips using 0.13-μm SiGe HBTs. To achieve high output power, two 5-stacked PAs with optimum inter-stage matching networks are combined with Wilkinson power combiners. Furthermore, a 3-stacked amplifier is used as the driving amplifier to increase the gain of the whole PA. During on-chip measurements, the X-band stacked PA achieves peak output power of 890 mW and maximum power added efficiency (PAE) of 17.8 %. The chip area is 1.9 × 1.4 mm² including the testing pads. To the authors´ knowledge, our proposed PA achieves the highest output power at X-band with a silicon-based technology.