Microstrip antenna feeding from a parallel-plate dielectric waveguide: analysis and experiment

The authors use a parallel-plate dielectric waveguide (PPDW) as a substitute for a printed stripline. The PPDW consists of a rectangular dielectric strip embedded between two parallel metallic plates. The PPDW cannot be printed, but can be fabricated with relative ease using an automated machining process for lower microwave frequencies, or using a microelectronic deposition process for better dimensional accuracy for higher-frequency applications. The guiding mode of a PPDW is the fundamental TE/sub 10/ mode, which supports an electric field (equivalently, a voltage) across the parallel plates, and does not itself radiate or leak to the surrounding parallel-plate structure. Further, any parallel-plate radiation from the slot is also expected to be confined and guided by the surrounding PPDW structure due to total reflection from its outer dielectric interfaces. The PPDW is also a lower-loss waveguiding medium, preferred over a stripline for higher-frequency applications.