Planar Slot-Line Slow-Wave Structure of a V-band Backward Wave Oscillator

A planar slot-line slow-wave structure (SWS) is proposed for a V-band backward oscillator (BWO). Consisting of only a metal sheet with a meander slot line and a metal shell, the proposed SWS is very simple to fabricate and assemble by using laser cutting and welding. High frequency characteristics and transmission properties of the proposed SWS have been investigated. According to results from particle-in-cell (PIC) simulations, this structure can produce 42.1 $\mathbf{W}$ of output power at 59.4 GHz. Additionally, it has a wide voltage tuning range of 8.2 $\mathbf{kV}$ and a 23% frequency tuning range with a central frequency of 56.5 GHz.