Revealing Surface Morphology and Suppression of Backward Current in Diodes Packaged With Permanent Magnet

Currently, backward current in diodes is a significant factor limiting the application of high-power microwave (HPM) devices packaged with a permanent magnet. This article experimentally observed typical morphological changes in diodes, such as the attachment morphology, micro-damage, and composition of sputtered products on the cathode rod surface caused by the backward current. Combined with particle-in-cell simulation, the connection between the backward current and typical morphological changes is revealed, illustrating the important influence of the anode on diode stability. Finally, an electrostatic shielding groove structure (ESGS) on the anode is developed from the perspective of slowing down the anode plasma movement. Experiments proved that this method can effectively suppress the backward current and improve diode stability.