1.    Determine the frequency range of operation needed, sometimes more than one amplifier is required.

2.    Determine if you need a Pulse or CW type of Amplifier.
Example: HIRF EMC applications require High Power Pulse Amplifiers

3.    Determine the minimum acceptable linear or saturated power needed from the amplifier. Harmonics should be considered based on the frequency range.
Example: As you go up in frequency antenna gain improves so a lower power amplifier may be acceptable but the higher gain of the antenna may affect the Harmonic Level.

4.    Assess the system losses between the amplifier and the Antenna/DUT.
Example: If the test setup has 6dB of losses then the Amplifier power needs to be 6dBm higher.

5.    Some modulations if required for the test application, would require a higher power amplifier.
Example: When performing an 80% AM modulation test the amplifier needs to have 5.1dBm of margin to accommodate the peak.

6.    Antennas, Cables, DUT’s & Rooms have cumulative VSWR, it is best to allocate for some power margin.
Example: working into a 2:1 requires 12% more forward power.

7.    Consider the application, is this a single test or will it be used repetitively.

8.    Consider your desired RF connection types and locations to be optimal for your application.

9.    Also consider if automation will be used so the appropriate remote capability is included.