Terahertz band gap properties by using metal slits in tapered parallel-plate waveguides

We present experimental and finite-difference time-domain simulation studies on the properties of Bragg and non-Bragg band gaps; the studies are carried out by using metal slit arrays positioned at the center of the air gaps in tapered parallel-plate waveguides. Two Bragg stop bands, with a dynamic power transmission range of about 26 dB, are observed for an air gap of 29 mu m. Two non-Bragg stop bands are observed for an air gap of 94 mu m. Using the Ey field distribution and Poynting vectors, we confirm that the Ey field leaking from the slit and the Ey field propagating from another input vanish because they are out of phase. The Bragg and non-Bragg stop bands determined in the simulations show excellent agreement with those observed experimentally. (C) 2010 American Institute of Physics. [doi:10.1063/1.3514558]