The high-current electron beam in the over-mode waveguide had driven the many kinds of microwave modes, it is very significant to study the high power microwave by measuring the microwave mode.

Results EBCT had the advantage of high speed in scanning and high resolving power of time without mechanical abrasion due to the using of electron beam.

As a convenient and cheap cathode, velvet can emit intensive electron beam and is widely used in high power electron devices.