Abstract: A semi-flexible double-ridge waveguide comprises a corrugated tube formed into a special dumbbell-shaped cross-section defined by parameters which are conveniently optimized to realize improved power-handling capability as well as improved attenuation and VSWR factors across extended dominant-mode operational bandwidths. The dumbbell-shaped cross-section efficiently removes the problems typically associated with the use of conventional rigid waveguide, including difficulty of installation as well as the need for precise alignment of components, by combining flexibility and ease of manufacture, even for long lengths of waveguide, through use of a continuous, uncomplicated and relatively inexpensive process.The dumbbell-shaped cross-section is totally devoid of corners and other abrupt protrusions and is defined by a geometric equation in which specific parameters can be correlatively optiminzed to improve desired electrical properties of the waveguide.

Abstract: A dual band circular polarizer for simultaneously transforming two to four linearly polarized waves of two different frequency bands into two to four circularly polarized waves, and vice versa, the polarizer comprising a waveguide of circular or square cross-sectional shape dimensioned to simultaneously propagate signals in two different frequency bands and two arrays of conductive elements, each array comprising a pair of diametrically opposed rows of conductive elements extending inwardly from the walls of the waveguide.

Abstract: A waveguide connection comprising the combination of a rectangular waveguide, an elliptical waveguide having a cutoff frequency and impedance different from those of said rectangular waveguide, an inhomogeneous stepped transformer joining said rectangular waveguide to said elliptical waveguide, said transformer having multiple sections all of which have inside dimensions small enough to cutoff the first excitable higher order mode in a preselected frequency band, each section of said transformer having a transverse cross-section defined by the equation: (2x/a).sup.p +(2y/b).sup.

Abstract: A multi-port, multi-frequency combiner comprising a main waveguide having a cross-section in the shape of a right-angle parallelogram and dimensioned to simultaneously propagate co-polarized signals in different frequency bands and at least one signal that is orthogonally polarized with respect to the co-polarized signals, at least a portion of the waveguide being overmoded; a plurality of junctions spaced along the length of the main waveguide for coupling selected signals in the different frequency bands in and out of the waveguide, at least one of the junctions being located in an overmoded portion of the waveguide, each of the junctions having an unbalanced or pseudo-balanced feed with only a single side-arm waveguide for transmitting and receiving the signals; and filtering means disposed within the main waveguide and operatively associated with each junction therein for signals in the highest frequency band, the filtering means having (1) a stopband characteristic for coupling signals in the highest fre