The Hybrid Continuous Spectrum of the Inset Dielectric Guide and its Application to Rectangular Waveguide to I.D.G. Transitions

The potential of the Inset Dielectric Guide,(I.D.G.), for both transmission and antenna applications has previously been demonstrated The analysis of discontinuities in the guide, particularly strongly radiating discontinuities requires a knowledge of its complete modal spectrum. The non-separable nature of the guide cross-section has to date, only permitted an approximation to the continuous mode spectrum to be formulated. The objective of this paper is to derive the hybrid continuous spectrum of the I.D.G., an example of an open non-separable waveguide, using a field matching approach. As an example of its use, we analyse rectangular waveguide to I.D.G. transitions achieving good correlation with experimental data.