Trends in microwave tube technology and markets past and future

The mini-tube TWT were products clearly motivated by markets which could be reasonably predicted and assessed. Today, the 'Vacuum Electronics Devices' (VED) industry, at least in the US, is entirely market driven. The inroads of solid-state devices continue to undercut sales not only in current applications, but, interestingly, also in future ones, for which no proven solid-state devices exist. The VEDs manufactured with solid-state technology, will find a niche market in millimeter-wave sources. In any case, it is not clear whether renewed growth in VEDs in likely to be spurred by new technology, developed with the limited government or private support now available in most countries, or a clear vision of developing markets.