Frequency-Doubling Millimeter-Wave Amplifier

We propose the experimental investigation of a frequency-doubling millimeter-wave amplifier (MWA) that has diverse applications such as short-wavelength radiation sources for sensors and associated systems. The MWA is proposed as a very compact, light-weight RF source in which an electron beam is injected into a deflection cavity operating at the drive frequency. A transverse magnetic field produces a "wiggled" beam which is then collimated and bunched at twice the drive frequency. These bunches are next passed through an electron-gain section (MTI dynode) composed of a very thin foil ("approx" 3um) of a high secondary electron yield material (such as diamond). The foil operates in the transmission mode and is designed to provide an electron gain of "approx" 50. The high-current bunches are accelerated and injected into an output cavity that operates in a TM010 mode at a frequency that is twice the drive frequency. Phase I is aimed at detailed analysis and 3-dimensional particle-in-cell studies to establish credible estimates of output power, efficiency, gain, and other key parameters leading to the construction of an operating device under Phase II.