A high‐power, coherent, W‐band (94 GHz) millimeter‐wave radar has been developed at the Naval Research Laboratory. This radar, named WARLOC, employs a 100 kW peak power, 10 kW average power gyro‐klystron as the final power amplifier, an overmoded transmission line system, and a quasi‐optical duplexer, together with a high gain antenna, four‐channel receiver, and state‐of‐the‐art signal processing. The gyro‐amplifiers and the implementation in the WARLOC radar will be described. © 2003 American Institute of Physics