This week's announcement by HEICO Corporation, that it had added noted TWTA and microwave power module (MPM) supplier dB Control to its Electronic Technologies Group, was something of a vote of confidence in that aging but trusted technology, vacuum electronics. Such devices as traveling-wave tubes (TWTs), klystrons, and magnetrons were core components in the earliest of microwave military systems and continue to be widely used in military and aerospace applications to this day.

Although users of vacuum-electronic devices in commercial broadcast, industrial, and even military applications have long read reports about the demise of this technology, it continues to thrive, even with growing claims of higher power levels from exotic semiconductor processes, such as silicon carbide (SiC) and gallium nitride (GaN) transistors. But what is the truth of how much power is really available from each technology at different frequencies, and which ratings refer to continuous-wave (CW) and which to pulsed power levels (and at what duty cycles)? For those interested, some of the answers will appear in an exclusive report in a special military electronics supplement in the March issue of Microwaves & RF.