RF windows of low reflectivity and absorption for high average power gyroklystrons

The major subjects of RF window design for high average power gyroklystron are to reduce there reflectivity and absorption power in order to enhance its stability and protect output window. In this paper, the window´s reflection and absorption are analyzed in detail. As an example, a sapphire window of 9 mm in diameter and 1.459 mm in thickness for 34 GHz, TE01 gyroklystron is presented. Its reflectivity is less than 1% if process error is within 2%, and its absorbing power is about 5 W while the output average power is 20 kW.