Constant magnetic field structure

The invention discloses a constant magnetic field structure which is characterized by comprising a first magnet and a second magnet oppositely arranged. A distance is reserved between the first magnetand the second magnet, and a constant magnetic field area for containing a workpiece is formed between the first magnet and the second magnet. The constant magnetic field structure can effectively focus strip-shaped electron beams such as a traveling wave tube, a klystron and a backward wave tube, and can also focus cylindrical electron beams and the like. 本发明公开了一种恒磁场结构，其特征在于：包括相对布置的第一磁体和第二磁体，第一磁体和第二磁体之间具有距离，第一磁体和第二磁体之间形成容纳工作件的恒磁场区。本发明的恒磁场结构，可以有效地为行波管、速调管、返波管等带状电子注聚焦同时也可以为圆柱形等形状的电子注聚焦。