A Broadband Extended Interaction Klystron Based on Multimode Operation

A novel broadband multimode extended interaction klystron (EIK) circuit is proposed to overcome the bandwidth limitation of the conventional single-mode EIK. The uniform-gap and stagger-gap extended interaction circuits are comparatively studied; the multimode operation is demonstrated; stability and feasibility of this multimode circuit are analyzed. A −3-dB bandwidth of 860 MHz (2.51% relative bandwidth) in
Ka
-band is predicted by a particle-in-cell simulation. Meanwhile, comparative study on the uniform-gap and stagger-gap circuits also explains the working mechanism of the conventional single-mode (
${\pi } $
mode) stagger-gap circuit.