Development of a 500 MHz high power solid state power amplifier based on GaN transistors

The adoption of Solid State Power Amplifier (SSPA) is rapidly increasing in major accelerators worldwide, replacing tube amplifiers such as Klystron and IoT. This study aimed to develop a High-Power RF system for Multipurpose Synchrotron Radiation Accelerators and to design and implement a GaN transistor-based SSPA. Through this research, we verified control performance equivalent to that of a 150 kW SSPA and successfully developed a prototype of a 5 kW RF module. Experimental results confirmed that the GaN transistor-based SSPA provides high efficiency and stable performance in the 500 MHz band, and based on this, we established a performance assurance plan for the 150 kW SSPA. This study demonstrates that GaN devices can effectively replace LDMOS devices with similar performance and competitiveness in the RF applications operating in the 500 MHz frequency range, which has traditionally been dominated by LDMOS. These results have significant implications for enhancing the performance and efficiency of High-Power RF systems and are expected to greatly expand the potential applications of GaN-based SSPA in various scientific and industrial research fields.