A 150–175-GHz 30-dB S21 Power Amplifier With 125-mW Pout and 16.2% PAE Using InP HBT

We report a five-gain-stage 150–175-GHz solid-state power amplifier (PA, SSPA) monolithic microwave integrated circuit (MMIC) having modest 20–21-dBm output power
$P_{\mathrm {out}}$
, high gain, and high power-added efficiency (PAE). The transistor technology is 250-nm InP HBT. The
$S_{21}$
gain is 31.4 ± 1.2 dB from 100 to 178 GHz. The 3-dB
$S_{21}$
bandwidth is between 96 and 181 GHz. Typical return loss values for
$\vert S_{11}\vert $
and
$\vert S_{22}\vert $
exceed 8.5 and 10 dB, respectively. The dc power is 0.72 W. Across 150–175 GHz, the saturated output power
$P_{\mathrm {sat}}$
is 106–126 mW with 16–18-dB gain and 12.5%–16.2% PAE—peak values for
$P_{\mathrm {out}}$
, gain, and PAE are at 170-GHz operation. The 1-dB gain compression
$P_{\mathrm {out}}$
(OP
$_{\mathrm {1\,dB}}$
) is 30–60 mW. Across the
$D$
-band (110–170 GHz),
$P_{\mathrm {sat}}$
is 82–126 mW with 9.1%–16.2% PAE. This work establishes a 1.62–
$1.89\times $
increase to PAE over 150–175 GHz operation at the output power and gain levels cited. It is also the highest RF output power demonstrated across the full 110–170-GHz WR6.5 waveguide band.