Development of a high-power X-band compact RF rotary joint

A high-power X-band (9.3 GHz) compact RF rotary joint has been designed, fabricated and tested in Tsinghua University. Simulation results illustrated that RF parameters (the scattering matrix) of this rotary joint keep stable in different rotation angle. Cold measurement using Vector Network Analyzer confirmed the simulation results. The maximum reflection was below -25 dB, the insertion loss was less than 0.1 dB, and the variance of output phase shifts was below 0.2 degree while rotating the joint. High-power test under a 1.6 MW X-band magnetron also showed good results. The design, cold measurement and high-power test of the RF rotary joint are presented in this paper.