Volcano-structured Double-gated Field Emitter Arrays; Emission Characteristics and Applications

Volcano-structured double-gated field emitter arrays (VDG-FEAs) have realized both highly focusing electron beam and high emission current. The prototype image sensor using Spindt-type VDG-FEA has obtained a reproduced image with uniform image intensity without magnetic focusing. we describe a compact image sensor using the VDG-FEA. We are developing a 300 GHz band traveling wave tube (TWT) using a thermal cathode. We believe that the VDG-FEA is a promising cathode for the 300 GHz TWT in the future.