A Compact High-Gain Ku-Band Multibeam Relativistic Klystron Amplifier With Low Guiding Magnetic Field

In this brief, a compact high-gain Ku-band multibeam relativistic klystron amplifier (MBRKA) is proposed to achieve high power and high efficiency with low-guiding magnetic field. A special anode structure with an inner conductor is designed to realize stable transmission of the intense relativistic multiple electron beams (IRMEBs) with low-guiding magnetic field. The compactness is realized by adopting the three cascaded double gap bunching cavities while maintaining high gain. The Ku-band MBRKA is designed to be an over mode structure to increase the power capacity. Combined with the device structure, an internal and external combined permanent magnet is designed, which can realize light permanent magnet packaging for the over mode MBRKA. The experiments were performed with a low magnetic field of 0.43 T. The output power, pulsewidth, and gain of the device were experimentally found as 630 MW, 80 ns, and 50 dB, respectively. Furthermore, the axial length between the input and output cavities is only 5.6 wavelengths.