Solid-State Ultra-High Power Amplifier Modules Based on 100 V RF GaN Technology for LINACS Operating at 325 and 650 MHz

Radiofrequency power sources are needed for high gradient high beam current linear accelerators capable of accelerating protons and ions to several GeV. Frequency of operation is 650 and 325 MHz. Both pulsed and continuous-wave applications are of interest. In this research work ultra high power solid-state radiofrequency sources are proposed operating at the stated frequencies of interest. The approach employs high voltage Gallium Nitride radiofrequency transistors operating at 100 V or higher to achieve 5-kilowatts continuous-wave and 10-kilowatts pulsed power level in a small form factor that reduces the required number of combiners and related losses to achieve Mega-Watts power levels. The design will employ harmonic tuning techniques as used in class E, F and inverse F power amplifiers to achieve >70% efficiency and assembly techniques that overcome heat dissipation in such high power density systems. Design and build large radiofrequency Gallium Nitride building blocks transistors rated at 600 W continuous-wave when operating at 100 V and 1-kW pulsed when operating at 150 V. For operation at 325 and 650 MHz these high voltage radiofrequency Gallium Nitride devices will feature 1 micron gate length needed for good phase and mismatch stability. The transistors will be characterized at the two frequencies of interest to demonstrate successful operation. The technology identified as suitable for high efficiency power source in particle accelerators can also be applied in several other industrial, scientific and medical applications such as microwave sintering, radiofrequency and microwave ablation, oil percolation, MRI scanners and Nuclear Magnetic Resonance spectrometers, etc… The high efficiency of these devices also translates into reduced electrical power consumption and lower cost of operation.