A +27 dBm Psat 27 dB Gain W-Band Power Amplifier in $0.1 \ \mu \mathrm{m}$ GaAs

In this work a W-Band power amplifier is presented in $\pmb{0.1 \ \mu\mathrm{m}}$ GaAs pHEMT. The amplifier is composed of $\pmb{1\times 4}$ and $\pmb{1\times 8}$ driving stages for high gain and of three successive $\pmb{1\times 8}$ power stages for high power. The stages were designed using a developed generic unconditionally stable unit cell. The output combiner was designed very efficiently with only 0.75 dB insertion loss to present each active device with $\mathbf{Z_{opt}}$. The amplifier has a small-signal gain above 25 dB and more than 26 dBm $\mathrm{P}_{\mathrm{sat}}$ over 93–102 GHz. Due to the chosen topology, the amplifier presents a rapid saturation achieving almost $\mathrm{P}_{\mathrm{sat}}$ after 6 dB compression. The PA demonstrates a peak output power of 27.3 dBm between 96–98 GHz. The measured PAE is around 12% over 93–102 GHz. It is the first power amplifier in GaAs demonstrating 0.5W of output power above 90GHz. The chip size is $\pmb{3\times 3\ \mathrm{mm}^{2}}$ including pads.