Substrate integrated image guide (SIIG) - A planar dielectric waveguide technology for millimeter-wave applications

A synthesized version of the standard dielectric image guide, called the substrate integrated image guide (SIIG), is proposed and presented. It provides numerous advantages related to fabrication precision, design flexibility, and assembly cost, whereas it still retains the low-loss properties of its conventional counterpart in the millimeter-wave range. This is achieved by artificially lowering the effective dielectric permittivity around a guiding channel through cutting a periodic pattern of air holes in a single high-permittivity substrate. In this way, entire circuits including millimeter-wave components can be fabricated and assembled subsequently by a lamination process. Details on the propagation properties of the SIIG and design rules are presented. Two different simulation approaches, which have proven useful for analysis are described, and theoretical results are validated by measurements of fabricated prototypes. It is shown that guide attenuation values as low as 35 dB/m or 0.07 dB/lambda(g) at 94 GHz can be obtained in practice with high-resistivity silicon as a substrate material.