A Compact 140-GHz, 150-mW High-Gain Power Amplifier MMIC in 250-nm InP HBT

We report here a compact 140-GHz, 150-mW high-gain solid-state power amplifier (SSPA) monolithic microwave integrated circuit (MMIC) demonstrated in a 250-nm InP HBT technology. It utilizes five-gain stages and two-way on-chip power combining. The amplifier measures 29.5-dB mid-band <inline-formula> <tex-math notation="LaTeX">$S_{21}$ </tex-math></inline-formula> gain and over 125-mW output power across 115–150-GHz operation. The peak 153-mW output power was measured at 140 GHz using only 2.7-mW RF input power—the associated large-signal gain is 17.5 dB with 9.8% power added efficiency (PAE). The 140-GHz OP_{1 dB} 1-dB gain compression power is 106 mW with 7.0% PAE. The dc power dissipation is 1.54 W and its size is only 0.75 mm². The 3-dB <inline-formula> <tex-math notation="LaTeX">$S_{21}$ </tex-math></inline-formula> gain roll-off is between 112 and 147 GHz. The 115–150-GHz output power variation at 0-dBm input drive is only ±0.5 dB. The peak PAE varies between 8.2% and 10.5%. This D-band result improves upon by <inline-formula> <tex-math notation="LaTeX">$2.3\times $ </tex-math></inline-formula> at 140 GHz the state-of-the-art peak RF power previously demonstrated by SSPA MMICs.