A model for slot-coupled nonradiative dielectric waveguide and microstrip line

Abstract

The nonradiative dielectric (NRD) waveguide provides a low-loss, planar transmission medium into the millimeter-wave region of the spectrum. A number of passive and active devices utilizing this waveguide have been demonstrated in the past. Its use in hybrid designs, containing other transmission lines, can be facilitated through the introduction of appropriate transitions and interconnections. The objective of this article is to present an engineering model for one such transition, namely the NRD-to-microstrip line coupler. The two media are coupled by means of a slot-aperture in a common ground plate. The fields of the NRD waveguide are represented in a complete spectrum of modes, permitting rigorous derivation of the associated Green function. The final results are stated in the form of an equivalent circuit suitable for inclusion in CAD procedures. Envisioned applications for this component include multilevel circuits requiring connections from an NRD waveguide network to a layer containing microstrip-fed devices or radiators. Published 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE7: 388–396, 1997