A 1-W Ka-band power amplifier using 0.15-μm InGaAs/GaAs E-mode pHEMT technology

This article presents a 1-W Ka-band power amplifier using 0.15-mu m InGaAs/GaAs enhancement-mode pHEMT technology. We have introduced a method to obtain the required output power through the characteristics of the unit transistor provided by the manufacturer. At first, the PA circuit is designed to effectively combine the output signals of eight unit transistors. From the measurement results, 28.5 dBm output was obtained at 28 GHz and the maximum efficiency was reached to 25%. In order to achieve 1-W output power, two power amplifiers were connected in parallel using T-junction line combiner. Finally, an output power of 30.1 dBm was obtained. At the same time, the PA efficiency is 14.1%. As a result of linearity verification, we confirmed that this power amplifier has the ACLR characteristics of less than -30 dBc up to 23.3 dBm output.