THz and Sub-THz MEMS-Fabricated Klystron Amplifier

Exploitation of the THz radio frequency regime (>100 GHz) is seriously hampered by the relative dearth of compact, efficient sources. We propose to extend the klystron RF amplifier, with its high power and efficiency, to the THz regime through the use of MEMS based fabrication techniques developed for micro-turbine and micro-rocket applications. We predict power density of approximately 20 W/cc, a power efficiency of greater than 1%, capable of supporting a 7x7 array on a 1 cm square die. Phase 1 of this multiphase effort will fabricate the basic klystron structure including electron source, drift tube, resonators, input and output waveguides, and collector to demonstrate the fidelity of the fabrication approaches. The silicon sections will be formed using deep reactive ion etching methods. The copper sections will be built with laminated copper. We will demonstrate the sub-micron dimensional tolerances required for the 200 GHz device to operate as designed. The fabricated device will be sectioned and measured to support 3-D simulations to confirm performance with as-fabricated dimensions. Phase II will extend the technology to higher frequencies (350-650 GHz) with more efficient structures. This leads to commercially useful working amplifiers for a broad set of applications.