A 21-26-GHz SiGe bipolar power amplifier MMIC

A three-stage 21-26-GHz medium-power amplifier fabricated in f(T) = 120 GHz 0.2 mu m SiGe HET technology has 19 dB small-signal gain and 15 dB gain at maximum output power. It delivers 23 dBm, 19.75% PAE at 22 GHz, and 24 dBin, 13% PAE at 24 GHz. The differential common-base topology extends the supply to BVCEO of the transistors (1.8 V). New on-chip components, such as on-chip interconnects with floating differential shields, and self-shielding four-way power combining/dividing baluns provide inter-stage coupling and single-ended I/O interfaces at the input and output. The 2.45 x 2.45 mm(2) MMIC was mounted as a flipchip and tested without a heatsink.