Solid state amplifiers are being increasingly used instead of electronic vacuum tubes to feed accelerating cavities with radio frequency power in the 100 kW range. Power is obtained from the combination of hundreds of transistor amplifier modules.

SSPAs offer a cost effective alternative to traditional traveling wave based amplifiers. Typically available at lower power levels, SSPAs can offer an alternative to TWTs for narrow band applications. While the basic functionality of the amplifier is the same in a high power solid state amplifier, multiple devices are combined into unit building blocks or power modules which, in turn, are combined to develop the needed gain and power. The network is fed by a high current, low voltage supply and, similar to TWTAs, added control and protection circuitry is usually incorporated into the amplifier.