Parallel-plate-waveguide-based devices for the terahertz region

In this work we present three devices based on parallel-plate-waveguides (PPWGs): a demultiplexer; a beam splitter; and an axicon. The PPWGs used in the construction of such devices are made out of stainless steel sheets and vary in longitudinal length (along the beam propagation direction) in a linear fashion. All the proposed quasi-optical elements can be easily tuned to work within different frequency ranges only by changing the spacing between the plates forming the PPWG's, making this approach attractive for the fabrication of active devices for communication applications.