Design of RF window for 42 GHz, 200kW gyrotron

This paper deals with the design of RF window for 42 GHz, 200 kW high power gyrotron. The simulation of RF window for 42 GHz gyrotron has been carried out using the Ansoft HFSS and CST microwave studio. In 42 GHz gyrotron double disc of diameter 85 mm and thickness 3.2 mm sapphire window and spacing (Coolant FC-75) of discs 2.7 mm has been used in the simulation. The return loss (S11) and insertion loss (S21) of the 42 GHz gyrotron window have been found as -47.3 dB and -0.04 dB respectively. The return loss and insertion loss of the S-band window have been found as -27.3 dB and -0.07 dB respectively at cylindrical waveguide length 33 mm. The simulated result has also been validated through experimental results for S-band window.