Circuit Design of A High Power, S-Band Eighteen-Beam Klystron

Circuit design for a high-power fundamental-mode multiple-beam klystron (MBK) is presented. This S-band circuit will be powered with a 42 kV, 41.6A, eighteen-beam electron gun currently under development. The circuit is comprised of six cavities. Three of which have two gaps to achieve desired gain and bandwidth in a reasonably short circuit length. Simulations with MAGIC-3D indicate peak RF power of 740 kW and 3-dB instantaneous bandwidth of> 11% is feasible in a circuit length of approximately 22 cm. Electronic efficiency and gain are 42% and 34-dB, respectively.