GaN Based S-Band 500W Solid State Power Amplifier (SSPA) Module for Troposcatter Communications

Abstract

S-Band Troposcatter communication requires a linear high power 2 kW SSPA. The desired SSPA needs to be realized by phase combining 500 W Power Amplifier Modules (PAMs). The paper provides the design and development of a GaN based wideband Solid State Power Amplifier (SSPA) PAM module with RF output 500 watts or +57dBm. The system utilizes modular design approach using 300W SSPA Pallet as the basic building block. The amplifier device Cree GaN HEMT CGH21240F, in class-AB bias, was selected for realization of basic amplifier. The I/p and O/p matching circuits were designed and simulated in ADS software. 30 mil Rogers RO4350 substrate was used for fabrication of PCBs. The output RF power up to +57 dBm and good linearity with Power Added Efficiency (PAE) around 40 percent was achieved.