The invention belongs to an oval sheet
beam electron gun, which is used with a travelling
wave tube, a backward
wave tube and the like. The oval sheet
beam electron gun comprises a shell, an
electric heating wire in the shell, a
cathode component, a focusing
electrode component and an
anode, wherein an emitting surface of a
cathode head of the
cathode component is a plane, the focusing
electrode component comprises a pyramidal focusing hole, and the
anode is positioned at an output port of the shell and provided with an
anode hole which is a cylindroid hole. The cathode head is made of
lanthanum hexaboride, the emitting surface of the cathode head is modified into a plane, a pyramidal hole with a rectangular axial section is used as the focusing hole, and the cylindroid hole is used as the anode hole, so that the oval sheet
beam electron gun has the advantages that the oval sheet beam
electron gun is simple in structure and convenient in
processing, the precision is easy to be guaranteed, devices are easy to be miniaturized, the production cost is low, current emitted by the cathode head is high in density, operation frequency of the devices and
current density of
electron beams can be improved effectively, the
electron gun is high in output efficiency and long in service life, and the like. The defects of complex structure, low
current density and unevenness of the electron beams, high evaporativity and short service life of the cathode in operation at high temperature, and the like in the prior art can be overcome.