Design of an X-Band Gigawatt Multibeam Relativistic Klystron Amplifier

To achieve gigawatt-level amplification output radiation in X-band, an X-band coaxial multibeam relativistic klystron amplifier is designed. When the diode voltage and diode current are increased to obtain higher output power, higher modes can seriously degrade Klystron performance and cause pulse shortening. Special measures are introduced in the device to suppress the higher mode excitation and avoid pulse shortening. Finally, pulse shortening is avoided in the coaxial multibeam relativistic Klystron amplifier. Output power of 2.1 GW with an efficiency of 40% is obtained in the particle-in-cell simulation when driven microwave power is only several kilowatts.