Terahertz traveling wave tube amplifiers as high-power local oscillators for large heterodyne receiver arrays

The size of existing and projected submillimeter heterodyne receiver arrays is rapidly increasing. As receiver arrays grow ever larger, the local oscillator power they require increases as well. We have developed Terahertz (THz) Traveling Wave Tube Amplifiers (TWTA) that promise to provide more than enough power in the 200 to 700 GHz frequency range to pump the largest arrays being planned for submillimeter telescopes. This technology combines revolutionary carbon nanotube cathodes and electron gun design with unique software modeling and micro-fabrication capabilities. We review key enabling technologies that make this breakthrough possible, present the design, realization, computer models and preliminary results of the THz TWT we have fabricated at 220 and 350 GHz