Eigenmode analysis of metal photonic band gap cavity for gyrotron operating in higher order mode

Abstract

In the present paper, a systematic analysis has been presented for designing a PBG cavity operating in a higher order mode.In particular, a 35 GHz photonic band gap cavity has been designed for TE 341 mode of operation and eigenmode analysis has been presented to ensure the device operation in desired mode with all possible mode competition.Two dimensional structure of triangular lattice has been used for modelling of PBG cavity.In order to obtain the structure band gap information, dispersion characteristics has been calculated using standard Yee cell based finite difference time domain (FDTD) method.With the global band gap, mode map has been calculated to demonstrate the occurrence of all possible modes in the PBG cavity.The usefulness of mode map has been illustrated to design the RF cavity using PBG structure replacing the conventional tapered wall cylindrical waveguide cavity used in gyro devices to achieve the single mode operation.