A 4-W X-band compact coplanar high-power amplifier MMIC with 18-dB gain and 25% PAE

The performance of a compact coplanar microwave monolithic integrated circuit (MMIC) amplifier with high output power in the X-band is presented. Based on our 0.3-/spl mu/m gate-length GaAs power pseudomorphic high electron mobility transistor (PHEMT) process on 4-in wafer, this two-stage amplifier, having a chip size of 16 mm/sup 2/, averages 4-W continuous-wave (CW) and 25% mean power-added efficiency (PAE) in the X-band, with more than 18-dB linear gain. Peak output powers of P/sub -1dB/=36.3dBm (4.3 W) and P/sub sat/ of 36.9 dBm (4.9 W) at 10 GHz with a PAE of 50% were also measured. Compared to previously reported X-band coplanar high-power amplifiers, this represents a chip size reduction of 20%, comparable to the size of compact state-of-the-art microstrip power amplifiers.