Recent developments in microfabrication have produced new opportunities in vacuum electronics.The variety of microfabrication applications in vacuum electronics is steadily growing.The impressive achievements are field emitter arrays(FEAs) for cold cathodes.A new class of microfabricated vacuum electron devices or "μVED" will make the microwave/millimeter wave tubes miniature and low costs.They will also work in terahertz frequency with power output up to 1W.