Performance of Weakly Relativistic Oversized Backward Wave Oscillators

Abstract

Performance of oversized backward wave oscillators (BWOs) is investigated. Due to the axial mode operation, there exists a critical value of beam energy for the oscillation, i.e., a starting energy. The output power depends on the beam radius and voltage. The maximum output powers are above 100 kW (K-band) and above 50 kW (Q-band). The corresponding quality factor Pf ² is about 6×10⁴ [kW·GHz²]. By changing the condition at the SWS end, an enhanced performance of the K-band oversized BWO is observed in a low magnetic field region about 0.4 T.