Design and Simulation Investigations of an X-Band Klystron-Like Relativistic Backward Wave Oscillator With Dual Modulation Cavities

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-band klystron-like relativistic backward wave oscillator (RBWO) has been designed and studied for its efficiency enhancement by implementing triple extraction and dual modulation cavities. The proposed dual modulation cavities klystron-like RBWO have been modeled in a finite-difference time-domain (FDTD)-based particle-in-cell (PIC) code to illustrate its beam–wave interaction behavior and to study the effect upon the fundamental harmonic current and growth of axial electric field. The PIC simulation of klystron-like RBWO operating at the magnetic field of ~2.9 T predicted an RF output power ~2.79 GW with operating frequency ~9.5 GHz and the power conversion efficiency ~73% without the shortening of the pulse up to ~300 ns of simulation time.