X-band high power GaN power amplifier design and implementation

Işık, Ali İlker
High frequency power amplifiers play a crucial role in design, development and overall performance of wireless communication systems. Demanding requirements of the power amplifiers require improvements in output power, efficiency and bandwidth. GaN devices attract high frequency power amplifier designers due to the superior material characteristics of GaN. In this thesis, a power amplifier operating at X-band is designed and realized using a GaN discrete bare die transistor. It provides over 15 W output power and 30% PAE in continuous wave(CW) operation and 20 W output power and 40% PAE in pulsed operation. Moreover, AM/AM and AM/PM measurements are also done for both operation modes to better understand nonlinearities of GaN devices and compare CW and pulsed modes. Furthermore, pulse phase stability and spectrum behavior of the PA are also measured to evaluate the PA from a system point of view. Nonlinear and EM simulations are performed using CST Microwave Studio and AWR Microwave Office together with the nonlinear model provided by the supplier of the transistor die.