Very wideband operation of twin-layer inset dielectric guide

An inset dielectric guide (IDG) with a multilayer dielectric filling is studied, using the transverse resonance diffraction, technique. The convergence and numeric efficiency of the analysis are good, and comparisons with experimental measurements of phase constant show the validity of the data produced. Those aspects of the IDG structure that limit its monomode bandwidth when it is filled with a single dielectric are investigated. It is shown how the monomode bandwidth of such an IDG may be made greater than that of rectangular metal waveguide by appropriate choice of aspect ratio. It is also shown how the simple use of two dielectric layers in the IDG slot can yield a guide whose monomode bandwidth is 66%, which is much greater than the typical operating bandwidth of a standard double ridge waveguide (40%). In the maximum bandwidth configuration, variation in the position of the boundary between the dielectrics produces little change in bandwidth. Hence, it appears that multilayer IDG is an attractive transmission media for wideband applications at both microwave and millimeter-wave frequencies