Investigation of photonic crystal structure for staggered double grating slow wave structure

A staggered double grid (SDG) slow wave structure (SWS) loaded with photonic crystals (PhC) operating at 220GHz is designed, and the problem of decreasing the dispersion caused by PhC is studied in this paper. In this paper the effects of the filling ratio and period of photonic crystals on the dispersion curve are presented and the SDG SWS loaded with PhC is designed. By observing the S parameter, it can operate stably at 220GHz, and the transmission loss is less than - 20dB. Compared with the traditional SDG SWS, this structure overcomes the mode competition and improves the stability of traveling wave tube (TWT).