Temperature measurements of a high-power microwave feedhorn window

Temperature measurements of a high-power microwave feedhorn window during transmitter operation at 365 kW CW and 8.5 GHz made using an imaging infrared radiometer are discussed. The window under investigation was constructed of HTP-6, a high-thermal-performance material developed to shield the Shuttle Orbiter from the heat of reentry. The measurement technique is described and experimental results are presented. The window performed adequately at 365 kW CW with a center temperature of 475°C. The tests verify that HTP-6 can be used as a window material or a support structure in high-power waveguide at power densities of 1.47 kW/cm² for extended periods of time, with no change in its mechanical characteristics