Ka-band Extended Interaction Klystron Research Articles

High-power Ka-band Extended Interaction Klystron Design Based on Internal Coupling Cavity

High-power Ka-band Extended Interaction Klystron Design Based on Internal Coupling Cavity

Design of a Hollow-Beam Electron Optics System With Control Focus Electrodes

The design of a hollow electron beam (HEB) electron optics system for a 10-kW Ka-band extended interaction klystron is presented. To lower the maximum cathode current density and realize the fast switch of the current emission, an HEB with two focus electrodes (FEs) is chosen, which attains to a high area compression ratio of over 100. A 25-kV, 2.5-A beam is produced by a curved spherical segment cathode with the area of 0.321 cm2 and an average beam loading of 8 A/cm2, namely, the high area compression ratio is necessary to reduce the cathode emission current density. The HEB with an area compression ratio of 105 can propagate 40 mm long with good laminarity confined by a 0.7-T uniform magnetic field. The beam current can be quickly shut off when the voltages of the FEs are biased to −4100 V. The results were simulated with two simulation codes: EGUN and OPERA 3-D. A sensitivity analysis with respect to critical parameters such as the displacement of FE1 and FE2 in the radial direction is provided. The simulation results of OPERA 3-D/SCALA and EGUN show an excellent agreement.

DESIGN ON KA-BAND FILTER LOADED THREE-GAP COUPLED OUTPUT CAVITIES

The extended interaction klystron(EIK) consists of several reentrant multi-gap coupled cavities.The demand for high-power microwave sources in the millimeter-wave region promotes the development of a Ka-band extended interaction klystron(EIK).In this study,the real part of the impedance of the three-gap coupled output cavities composed by three uniform gap cavities was derived by using the equivalent circuit theory and field analysis method,respectively.The basic parameters of the broad band output circuit were obtained by using equivalent circuit theory.Filter loaded three-gap coupled output cavities with band width of 4.6% were designed by using field analysis method.It lays a solid foundation for the development of the broad band EIK.