Multi-MW 22.8 GHz Harmonic Multiplier

High-power radio frequency (RF) sources with frequencies between 17 and 34 GHz are required to achieve high acceleration gradients (of the order of 150 MV/m) in warm (room temperature) accelerator structures, so as to allow the design of a future multi-TeV electron-positron collider. This project will develop a 50-MW phase-stable source at 22.8 GHz as a second-harmonic frequency multiplier, using drive power at 11.4 GHz derived from an existing SLAC klystron. By using an existing electron gun and modulator, rather developing them anew, the project should be able to realize its goals within the time and budgetary limitations of an SBIR project. The frequency multiplier to be designed (Phase I), built and tested (Phase II) is to be a two-cavity device in which a pencil beam is energized by cyclotron resonance acceleration in the first (dipole) cavity. The device then will transfer its added energy at the second harmonic in the second (quadrupole) cavity. Simulations have shown that the efficiency for power transfer between the two frequencies can be over 95%, thus allowing 48 MW of pulsed power at 22.8 GHz to be generated when the device is driven by 50 MW at 11.4 GHz. Commercial Applications and other Benefits as described by the awardee: The use of harmonic multiplication, for the generation of RF power at frequencies where no commercial source exists, should open up markets for radar and communications, and for other industrial and military uses of high-power microwaves.