Analytical and Experimental Study of Multilayer Dielectric Rod Waveguides

This article presents a comprehensive study of the design and performance of a multilayer dielectric rod waveguide (MDRW) with a rectangular cross section. The design is comprised of a high permittivity core encased by a low permittivity cladding. A mathematical model is proposed to predict the fundamental mode cutoff frequency in terms of the core dimensions and the core and cladding permittivity. The model is useful for design purposes and it offers an excellent match to full-wave electromagnetic (EM) simulation results. The MDRW performance is measured for the extended Ku-band (10-18 GHz) considering straight and bent waveguides with different radius of curvatures. The particular multilayer configuration shows a 16.7% and 24% extension of the 1 dB low-band cutoff frequency for a 10×10 mm2and 20×20 mm2cladding area, respectively, when compared to a single layer dielectric rod waveguide (DRW) design of the same core dimensions. MDRW bends also exhibit a significant reduction of the 1 dB low-band cutoff frequency from 20% to 40% when compared to single-layer designs, for the different radius of curvature bends.