Abstract: A multi-tone multi-band tunable millimeter-wave synthesizer is provided. In some embodiments, the multi-tone multi-band tunable millimeter-wave synthesizer is configured to simultaneously generate multiple frequency tones for space-borne beacon transmitter for atmospheric radio wave propagation studies. The apparatus includes a comb generator, which puts out evenly spaced harmonic frequencies of the input signal, which are coherent, tunable, and the number of tones or combs is scalable over a wide range of frequencies. These harmonics or tones are amplified to the power level needed for radio wave propagation studies. The amplified signals are transmitted as beacon signals from a satellite to a ground receiving station.

Abstract: A multibeam, electrostatically focused klystron includes a plurality of conductive members, ones of which are recessed to provide input and output sections of microwave cavities, wherein focusing voltage is applied between those sections. The conductive members are either spaced along the path of multiple beams, or stacked in insulated relation, in either case being supported by glass rods within a glass envelope.