It is important to keep the following in mind when selecting an amplifier for EMC testing:
Technology - In general EMC amplifiers are based on various technologies and functionality.
Solid state amplifiers’ design involves the biasing of RF transistors (primarily MOSFETs). Alternatively, TWT (Traveling Wave Tube) amplifiers are a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range.
The choice of technology used is dependent on many factors. For high frequency applications (above 1 GHz) utilizing high power (above 100 W or so), a TWT would be the only choice currently available. High power, low frequency applications will utilize solid state technology. Additionally, some amplifiers will use solid state technology above 1 GHz, but power output will be lower than that of a TWT. It is all dependent on what your application requires.
In addition to choosing the appropriate technology, it is important to consider how the signal will be amplified. A CW amplifier continuously amplifies any signal introduced into its input, as long as it is within the operational range of the amplifier. This includes both continuous wave signals and modulated signals. Pulse amplifiers, however, will only amplify a signal introduced at the input when an additional pulsed signal is applied to a pulse input, resulting in a gating-type function for pulsed applications.