A 1.5 KW L-Band All GaN High-Efficiency Solid State Power Amplifier for Pulsed Applications

This paper describes the design and fabrication of a 1500 watts multi-stage L-band RF solid-state power amplifier (SSPA). The basic approach is to use 50-volt Gallium Nitride High Electron Mobility Transistors (GaN-HEMT) for all the stages to ease the requirements for DC power supply, and a step towards the integration into a single chip. So, the main structure of the proposed power amplifying chain is to use 2-parallel connected 800-watt PAs to provide the required output level preceded with a multi-stage cascaded driver to provide the required gain and the power level required by the output stage. A 5-watt amplifier plays the role of a pre-amplifier stage, followed by a 30-watt PA, and finally, a 100-watt PA was employed to generate the necessary power level required to deliver the power stage. The implemented solid state power amplifier chain achieves 1.5 KW total output power, 57 dB power gain associated with total power added efficiency (PAE) of more than 50% when derived with a pulsed input signal with a duty cycle of 5% and pulse duration of $100\ \mu\text{sec}$.