Simulation of a G-band sheet beam backward wave oscillator with double staggered metallic rod array

Backward wave oscillators (BWO) are promising high-power portable radiation sources in the terahertz frequency range. A G-band (140-220 GHz) sheet beam BWO based on a double staggered metallic rod array as the slow wave structure (SWS) has been designed and presented in this paper. The novel SWS allowed extension of the interaction area for the sheet beam with a uniform electric field if the height of the rod array is properly chosen. This could alleviate beam instability problems in the sheet beam transportation and potential parasitic oscillations. Moreover, a relatively broad bandwidth can be achieved due to its special dispersive properties. Particle-in-cell simulation had predicted that the G-band sheet beam BWO with the improved non-uniform double staggered metallic rod array can achieve output power of over 110 W in a continuous frequency tuning range of 186.3-227.2 GHz (relative bandwidth 20%) with a maximum electronic efficiency of 2.8% by using a 200 mA sheet beam and adjusting the beam voltage from 20 to 40 kV