A 50–80mW SSPA from 190.8–244GHz at 0.5mW Pin

A 190.8-244GHz solid-state power amplifier MMIC is presented demonstrating 50-80mW P_out at 0.5mW P_in and 1.77W P_DC. This represents >20dB of large-signal gain across 53GHz of high-power bandwidth, where PAE is 2.8-4.5%. This 3-stage amplifier has >28dB S₂₁ gain from 207-271GHz, peak 35dB S₂₁ gain at 220GHz, and >30dB S₂₁ gain from 210-238GHz and from 256-268GHz. A power-cascode cell topology is used for the PA unit cell, and 4:1 power combining of these cells achieves the RF powers claimed. By reducing the DC power of only the 1^st and 2^nd stages of the MMIC, little reduction to the saturated RF P_out is observed. At 1.27W P_DC, the MMIC demonstrates 43-78mW P_out at 0.5mW P_in over the same 190.8-244GHz bandwidth, where now the PAE is 3.3-6.1%. This work improves upon the state-of-the-art by demonstrating simultaneously higher gain by 3-8dB, increased bandwidth by 1.5× (small and large signal), increased large-signal operating frequency (past 230GHz to 244GHz), and increased PAE by 1.4 × for an SSPA at these RF output levels.