Investigation on the strong-coupling multiple-gap cavities for the W-band sheet beam extended interaction klystron

A novel type of strong-coupling five-gap extended output cavity is investigated for the W-band SBEIK to verify its resonant advantages of mode separation, gap fields coupling and RF energy exporting etc. And the degeneracy mode competition for the strong-coupling five-gap cavity is studied due to its axial period structures. The result shows that the frequency interval between the work mode and vicinal non-working mode is above 600MHz, which is higher enough than the required 100MHz bandwidth for the SBEIK. Then, the 3D PIC simulation software is used to calculate the beam-wave interaction for the strong-coupling five-gap extended output cavity, the expected high output is observed with the corresponding performance and favorable stability.