Micro Vacuum Backward Wave Oscillator Terahertz Source

A sweeping and scanning system uses four micro-scale backward wave oscillator (MBWO) sources to cover the 170 - 800 GHz range. The MBWOs use high current density edge emitter cold cathodes to emit a sheet beam over a micromachined slow wave structure. A beam energy homogenizing structure increases efficiency compared with thermionic BWOs and reduces the need for magnetic confinement of the beam. Shared magnets and power supplies, and the improved efficiency of the MBWO, reduce the size and power of the system to well under 1/10 that of conventional systems. Continuous tuning or locking within and MBWO are accomplished by controlling the beam voltage with a phase lock loop control system. The control system also provides instantaneous switching between bands.