Investigation of higher-order modes in finite-width parallel-plate waveguide

Abstract

Transverse electric modes in finite-width parallel-plate waveguides were described and investigated. Electric and magnetic field components of the modes were evaluated, assuming that boundaries at both sides of the parallel-plate waveguide were perfect magnetic conductors. The existence of the modes was verified by simulation, experimental measurement of a parallel-plate waveguide cavity. As the cut-off frequencies of the reported transverse modes are lower than even those of TE1 and TM1 modes, which are generally considered the lowest, the characteristics of the transverse modes must be considered before using parallel-plate waveguides. Changes in the modes due to imperfect boundaries were also studied.