4. Other electronic tube families

Other tubes are being researched to extract very high peak power, some of which may well have major market potential. It's impossible to describe them here; we'll just mention a few.

The best-known are amplifiers derived from the gyrotron principle. Gyroklystrons and gyroTWTs are designed for applications requiring hundreds of kW _c between 20 and 140 GHz, mainly trajectory radar. The peniotron is a variant of the gyrotron, which makes do with weaker magnetic fields, hence its interest.

Russian researchers have come up with other CRM tubes where the beam follows a helical trajectory synchronized with a circularly polarized wave. But unlike gyrotrons and other gyroklystrons, the electrons remain monokinetic: there is no bunching. The advantage of this is very high efficiency (75% class), since...