Studies on high power THz radiation using nanosecond pulse in oversized Relativistic Backward Wave Oscillator

To design high power oversized Relativistic Backward Wave Oscillator (RBWO) which can generate GW-level Power in THz frequency, numerical studies such as finite difference time domain (FDTD) and particle in cell (PIC) were performed. 0.1GW at 0.1THz was estimated. The Oversized BWO which means relatively wide cross-section space (oversized) to decrease power density comparing with fundamental BWO is made up of slow wave structure (SWS) of rectangular type wall radius designed to generate wave on surface with strong interaction between electron beam and wave under intense fields at 500 kV-1.5kA, 100ns pulse in the relativistic range. In the meantime, the type of THz EM waves radiated antenna is COaxial Beam Rotating Antenna (COBRA). The antenna lens is designed to be matched with the W-band frequency and the thickness of lens is decided by theoretically calculation and results of numerical methods. On the basis of the results from numerical studies, it is designed and fabricated to generate radiated 0.1GW-0.1THz for 30ns, electromagnetic wave on the range of millimeter wave through these studies.