Analysis of Ohmic loss due to non-ideal boundary in relativistic backward wave oscillator

Radio frequency Ohmic loss due to non-ideal conductor boundaries seriously limits the performance of electronic devices. In this paper, the Ohmic losses of two simple models are calculated by particle-in-cell (PIC) simulation, which is also verified by theoretical calculation. Thereafter, based on PIC simulation, we have studied the variation of the Ohmic losses of relativistic backward wave oscillators (RBWOs) with operating frequency and material conductivity. The PIC simulation results show that as the frequency advances, the Ohmic losses of RBWOs deteriorate sharply. The power loss becomes non-negligible when compared with the output power. The loss-power ratio of a V-band RBWO made of stainless steel is over 25%. The non-negligible Ohmic loss can explain to some extent that the difference between the simulated and the experimental output power of the RBWO becomes apparent as the working frequency increases.