Investigation of Microstrip Meander-Line Traveling-Wave Tube Using EBG Ground Plane

A novel electromagnetic bandgap meander-line (EBG-ML) slow-wave structure (SWS) is proposed for improvement of the interaction impedance and reduction of circuit attenuation by in-phase reflection of EBG for traveling-wave tube applications. With high on-axis interaction impedance, the EBG-ML SWS can interact with a low-current-density electron beam. The backward-wave mode of EBG-ML SWS can be suppressed by the transmission stopband of EBG. Particle-in-cell simulations are carried out for the proposed structure with a sheet beam source. The simulation results show that a 50% improved interaction impedance and a 20% reduced circuit attenuation of EBG-ML SWS can be achieved, in comparison with those of traditional ML SWS. With a small input signal, the RF efficiency of EBG-ML is improved by 137.5% over that of the ML SWS.