A novel BWO with photonic band gap structure

A novel back-ward wave oscillator (BWO) with photonic band gap (PBG) structure is proposed. The PBG structure offers mode-confining and choosing mechanisms, restraining the lower modes and making the BWO operate at the higher modes. With the method of numerical simulation, a single TM03-like mode is obtained at Ka band in a triangular lattice dielectric PBG structure with the medium cylinder radius 0.12 cm, the distance between the nearest rods 0.31 cm, and the permittivity 4.0. The complete dispersive characteristic of electromagnetic modes is obtained. During 36~40 GHz, the device can operate in back-wave situation with the period of 0.4 cm.