Abstract: Two or three conductor coplanar transmission lines and lossy coplanar resistive films are formed on a surface of a substrate. The resistive film dimensions and resistivity are selected to suppress various spurious electromagnetic modes within and around the substrate. The resistive films may be positioned along the outer edges of the transmission lines or between the transmission line conductors. The resistive film may have regular spaced openings for producing an average resistivity different than that of a continuous resistive film. In one embodiment, a signal conductor has a serpentine shape and resistive film elements are positioned between adjacent sections of the signal conductor. In another embodiment, interdigitated resistive film elements extend between transmission line conductors.

Abstract: A transition is provided for interfacing a coplanar waveguide with a three dimensional microwave waveguide. The transition includes three coplanar conductors that are formed integrally with and extend from the coplanar waveguide. The transition extends into the microwave waveguide through a slot, with the plane of the transition being perpendicular to the direction of propagation of the electric field in the waveguide. The center conductor of the transition is a patch whose width increases. The other two conductors are attached to the side conductors of the coplanar waveguide and to the exterior of the waveguide. They flank the patch and have curved edges complementary to those of the patch. The gaps are initially narrow, and become wider gradually. Further, as each guide steers the electric field while changing direction by 90.degree., it rotates the orientation of the electric field vector by the same amount.

Abstract: An appliance is provided for installation within the mouth of an individual to prevent obstruction of the natural airway of the individual and to enhance natural ventilation during sleep. The appliance is hollow and constructed of material which is custom-molded to the user. An external negative air supply is provided which connects to a tube extending from the appliance and draws air from the hollow appliance creating a partial vacuum in the user's retroglossal area urging the user's tongue and soft palate away from the user's posterior pharyngeal wall and thereby opening an airway to the user's nasal cavity. A sensor provides control information to the negative air supply by sensing relative pressure in the user's oral cavity. The natural breathing cycle is thus facilitated but not controlled by the appliance.