Effects of Air Gap and Finite Metal Plate Width on NRD Guide

A potentially serious problem that may arise with nonradiative dielectric ( NRD ) guide circuitry is described. First, a small unwanted air gap would generate a leaky hybrid mode that could produce cross talk between components of a circuit, and, second, if the plate width were also finite another type of leaky mode would be created similar to the well-known channel guide leaky mode. Under appropriate circumstances, this additional mode would couple to the leaky NRD guide mode and seriously complicate the performance characteristics of the NRD guide.