A dielectric waveguide for propagating electromagnetic signals includes a cladding and an electrically conductive shield. The cladding has a body composed of a first dielectric material. The body defines a core region therethrough that is filled with a second dielectric material different than the first dielectric material. The cladding further includes at least two ribs extending from an outer surface of the body to distal ends. The shield engages the distal ends of the ribs and peripherally surrounds the cladding such that air gaps are defined radially between the outer surface of the body and an interior surface of the shield.