A 3-Watt Q-Band GaAs pHEMT Power Amplifier MMIC For High Temperature Operation

A three-stage Q-band pHEMT power amplifier for 42-46GHz operation has been designed and built. The conservative stage peripheries of 2.64:5.28:7.68mm were chosen to ensure high temperature operation. Although designed for a nominal bias of 5.5V and 170mA/mm, the amplifier operates with biases of 2-6V and 65-190mA/mm. Record powers for this frequency range have been obtained. Biased at 6V and 170mA/mm the amplifier provided 4W of power at 20% efficiency over 42.5-43GHz at 30degC, and an average of 3W with 17% efficiency over 43.5-45.5GHz at 90degC. At 5.5V and 128mA/mm an average power of 3W with 20% efficiency was obtained over 43.5-45.5GHz at room temperature