A Miniaturized 0.5-Watt Q-band 0.25-μm GaAs PHEMT High Power Amplifier MMIC

The performance of a very compact power amplifier MMIC for Q-band applications is reported. Using a 4-inch 0.25-μm GaAs power PHEMT process, this 4-stage amplifier achieved a linear gain of 19 dB over the 36 to 45 GHz frequency range, with an output power at 1-dB gain compression of 26 dBm (P
_-1dB
=400 mW), and a saturated output power of 0.5 Watt (P
_sat
=27 dBm), for a chip size of only 2.25 mm
²
(1.25 × 1.8 mm
²
). Compared to state-of-the-art power amplifier MMICs operating in the 36-43 GHz frequency range, the combined output power- and gain- densities per chip area are nearly a factor two higher, namely 220 mW/mm
²
and 8.5 dB/mm,sup>2.