An Ultra-wideband GaAs pHEMT Distributed Power Amplifier

A 0.5-7 GHz power amplifier (PA) is designed and fabricated in a 0.15 μm GaAs pHEMT process in this paper. To achieve a broadband power performance, this PA implements a nonuniform distributed amplifier configuration with four amplifying cells. Meanwhile, the transistor-stacking technology is applied in this PA to enhance the wideband power gain. Biasing with a 12 V drain voltage, this PA shows the measurement results of about 1-watt output power in the frequency range of 0.5-7 GHz with corresponding power added efficiency of 18-24%. The measured S-parameters show a very flat gain (S
₂₁
) of 14±0.4 dB, a maximum input return loss (S
₁₁
) of -16 dB, a maximum output return loss (S
₂₂
) of -11 dB. The chip occupies a small chip size of 3×2.5 mm
²
.