Comparison between solid-state and electron tubes amplifiers

This article offers a comparative analysis of power amplification technologies, based on electron tubes (TWTA, klystrons or tetrodes) or solid-state solutions (SSPA). The first section describes the various parameters that the user is comparing: beyond the ability of one or other technology to deliver power at the required frequency, these include purchase cost, cost of ownership, reliability and operational availability, and of course, compliance with performance targets, for example in terms of bandwidth and linearity, volume and mass. Electrical efficiency at saturation and operating point will be of particular interest, as will noise performance.

We then propose a more in-depth analysis of three major application sectors where both technologies are used: radar for defense applications, where the emergence of active electronically scanned antennas is now the most important factor in the choice of technologies; particle gas pedals, where pure power requirements are particularly high, often in excess of 1 MW; and, on the other hand, satellite communications systems, which require moderately high power – in the hundred-watt class – at centimetric and millimetric frequencies, and in addition very good electrical efficiency combined with linear behavior. For each of these applications, the article explains the power requirements and the main selection criteria.

At the end of the article, readers will find a glossary of important terms used in the article, as well as a table of acronyms and symbols.