ELECTRON-GUN WITH FIELD-EMISSION ARRAY CATHODES FOR VACUUM MICROWAVE DEVICES

Based on computer simulation, the possibility is studied for the creation of electron guns with multielectrode field-emission array cathodes (MFEAC) for vacuum microwave devices. In comparison with the known Spindt field-emission cathode of the diode type, MFEACs provide low levels of electrons transverse velocities on cathode. Two additional electrodes separated with thin dielectric films are employed in MFEAC: One of the electrodes (focusing) is electrically connected to a emitter, and the second one (accelerating) is connected to an extracting electrode. All the electrodes in MFEAC jointly make up electrostatic lens, which focuses microbeams coming from point emitters. The technique is presented for computer simulation of microbeam formation processes in MFEACs cell and in electron gun with MFEAC; the optimum sizes of the MFEAC cell are specified, providing the suppression of electron's transverse velocities. The results are described for the simulation of electron gun for a miniature multiple-beam klystron with 100 W output average power in the short-wave section of cm-wavelength range.