Dispersion-free and low-loss propagation of THz signals in a metallic slit waveguide

In this paper, a metallic waveguide concept that combines dispersion-free and low-loss propagation characteristics with two-dimensional mode confinement over a broad frequency range. Waveguide consists of two planar arranged metalized slabs of 300 mum thickness separated by a 270 mum wide slit. The width a of each slab in x-direction is 20 mm and is considered as quasi-infinite in terms of the propagating mode. The considered transmission signal is the fundamental TEM mode propagating along the slit in z-direction with the main field component in x-direction. For the evaluation of propagation characteristics and field distribution we apply a commercially available Maxwell solver software package based on the finite element method with a non-uniform adaptive mesh optimization routine. We plot the electric field amplitude at the waveguide's cross-section at 0.5 THz. At this frequency more than 60% of the guided power is confined within an area not exceeding one wavelength around the slit.