A 650-GHz Backward Wave Oscillator Based on Axial Loaded Double Defected-Photonic Crystal SWS

Axial loaded Double Defected Photonic Crystal (ADD-PC) with a cylindrical beam channel is introduced as a slow-wave structure (SWS) for backward wave oscillator (BWO) source design. The structural and the geometrical dimensions of the proposed SWS for submillimeter wave regime are realizable using the modern microfabrication processes. Starting from the basic design; the dispersion diagram, the modal phase velocity, and the beam interaction impedance are calculated. The effect of fabrication tolerance on both the operating frequency and the beam interaction impedance is also discussed. Using a custom built numerical electron beam-wave interaction algorithm, the electromagnetic field generation supported by the ADD-PC SWS is analyzed thoroughly. Simulation results indicate that with the proposed BWO, an output power of almost 8 W at 650 GHz with 1.8% conversion efficiency can be achieved.