A microelectromechanical microwave vacuum tube device is disclosed. The device consists of a cathode formed on a substrate, the cathode comprising electron emitters. A cathode emission control grid is also attached to the device substrate. The device further includes an output structure where amplified microwave power is removed from the device. In the device, the cathode surface and the grid surface are substantially parallel to each other and substantially perpendicular to the substrate. One of either the cathode, the grid, or both the cathode and the grid, are attached to the device substrate by one or more flexural members. The device further comprises an anode that is substantially parallel to the cathode surface and the grid surface.