Development of a compact X-band variable-ratio RF power splitter

A novel X-band (11.424 GHz) radio frequency (RF) power splitter has been designed, fabricated and tested at Tsinghua University. With E-bend waveguide structures and a modified concave bottom polarizer introduced in this work, a compact geometry is achieved. The RF power division ratio of two output ports can be adjusted arbitrarily by changing the position of a short circuit piston, controlled by a servo motor precisely. The input port maintains a good match at any output ratio. The parameters are optimized to acquire high RF power transmission capacity and large bandwidth. The cold test indicated that the max input reflection is -33.1 dB and the max output transmissions are -0.07 dB and -0.12 dB respectively, which agrees with the simulation results well. The high-power test was operated on Tsinghua High Power Test Stand. After days of conditioning, the RF power splitter can be operated steadily at 53 MW 250 ns input power with 20 Hz repetition frequency.