HiFIVE: High Frequency Integrated Vacuum Electronics

The millimeter wave (MMW) and sub-MMW part of the spectrum is of interest to DoD. Several relevant DoD and commercial applications including high-bandwidth communications, collision-avoidance radar, security screening, and high resolution imaging; and this region of the spectrum remains largely unexploited due to the challenges in accessing upper MMW and sub-MMW frequencies.

Vacuum electronic devices are frequently used as high power amplifiers at frequencies approaching the MMW and sub-MMW part of the spectrum. Traditional vacuum electronic devices are custom-built using numerous discrete components. For a vacuum electronics device to operate at MMW and sub-MMW frequencies and remain compact they must be highly integrated and fabricated by utilizing state-of-the-art micromachining techniques.

The objective of the High Frequency Integrated Vacuum Electronics (HiFIVE) program is to develop an integrated, microfabricated vacuum electronic (VE) high-power amplifier (HPA) circuit for use in high-bandwidth, high-power transmitters. The program will demonstrate operation of such a circuit over a 5 GHz frequency band centered at 220 GHz. The HiFIVE program is pursuing innovative technologies and approaches in several areas including high current density cathodes, high-power electron beam transport, and microfabrication of an interaction structure to enable an integrated, microfabricated vacuum electronic (VE) high power amplifier (HPA) circuit. There are two main areas of development: the necessary circuit elements to achieve a compact high-performance 220 GHz VE HPA, and the design, construction and demonstration of the high power amplifier and its demonstration.