AR’s 20S6G18A and 40S6G18B are self-contained, air-cooled, broadband, Class A solid-state amplifiers designed for applications where instantaneous bandwidth, high gain and linearity are required. The Model 20S6G18A, when used with a sweep generator, will provide a minimum of 20 W of RF output power instantaneously from 6 to 18 GHz, while the 40S version delivers 40 W.

These instruments are suitable for radiated immunity testing, TWTA replacements, and EW applications. 

20S6G18A
https://www.arworld.us/html/18200.asp?id=1320

40S6G18B
https://www.arworld.us/html/18200.asp?id=1343