The vast majority of microwave applications are the communication systems, radars,
environmental sensors, and medical systems. High power RF applications using microwaves
are gaining momentum, such as the Positron Emission Tomography (PET) using radioisotopes
to determine the exact location and size of a tumour. The radioisotopes required are produced
using a cyclotron powered by a high power RF source. In oncological treatment, Proton
Therapy is using high power amplifiers in combination with linear accelerating cavities or
cyclotrons to form a beam of protons to irradiate diseased tissue. On a larger scale, high power
RF sources are crucial for the successful operation of the future ESS and the High-Luminosity
Large Hadron Collider (HL-LHC) at CERN.
In this lecture, the focus is on solid-state power amplifiers as RF high power sources, a key
element of a large number of microwave applications. The ongoing research on semiconductor
technology allows foreseeing that in the frequency range of 100 to 2000 MHz, solid-state
power amplifier (SSPA) will be the dominant technology of the future, with SSPAs being more
efficient, more reliable and cost effective RF power sources.
Finally, I will introduce my own research activities in this area and describe the various
challenges we face today. I will provide some answers to the questions related to the increase
in power of RF power sources using solid-state amplifiers and to the energy efficiency
optimization for particle accelerator applications.