2. Comparison for a few critical applications

Figure 5 shows, from a bird's-eye view, the fields of application for one or other power amplification technology (solid-state or tube). For most low-power applications (less than a few dozen kilowatts at low frequencies, less than a few hundred watts above a few GHz), solid state is the obvious choice: mobile telephony (handsets and other portable devices, of course, but also base stations (links to mobiles and microwave links), FM and TV radio transmitters, MRI scanner transmitters (three applications that used tubes a few years ago)... Others are satisfied only with tubes, when the megawatt class is reached or exceeded. Here, we'll focus on the middle ground, where most of the debate is taking place in 2018: radar,...