Abstract: A window/seal and a satellite ground station antenna using the window/seal. A window/seal for a circular waveguide includes a right-circular cylindrical window having an axis, an annular recess surrounding and coaxial with the cylindrical window, and an annular rib surrounding and coaxial with the annular recess. An outer diameter of the annular rib is configured to fit closely within an inside diameter of the circular waveguide.

Abstract: A mechanism to connect first and second circular waveguides. A first member includes two or more pins extending radially from a body, the first waveguide coaxial with the body and terminating at a first port at an end face of the body. A second member has a cavity coaxial with the second waveguide and configured to fit over the first member, the second waveguide terminating at a second port within the cavity. Slots disposed around a perimeter of the cavity engage the two or more pins. A cap fits over the second member, the cap including L-shaped slots to engage the two or more pins extending through the slots of the second connecting member. A wave spring between an inside surface of the cap and a shoulder of the second member urges the second port towards the first port when the cap is engaged with the two or more pins.

Abstract: An antenna may include a primary reflector having a ring focus; a feed body along an axis of the primary reflector, the feed body including a circular waveguide coaxial with the axis of the primary reflector; a sub-reflector disposed facing an end of the circular waveguide; and a generally cylindrical stem extending from a center of the sub-reflector into the circular waveguide to form a section of annular waveguide. A sub-reflector support may mechanically connect a perimeter of the sub-reflector and an outside surface of the feed body. The sub-reflector, the stem, and the feed body may be collectively configured to couple microwave energy between the annular waveguide and the primary reflector.

Abstract: An ortho-mode transducer may include a cylindrical common waveguide terminating in a common port, a rectangular vertical branch waveguide in-line with the cylindrical common waveguide and terminating in a vertical port, and a rectangular horizontal branch waveguide normal to the common waveguide and terminating in a horizontal port. The vertical branch waveguide may be configured to couple a first linearly polarized mode from the vertical port to the common waveguide. The horizontal branch waveguide may be configured to couple a second linearly polarized mode, orthogonal to the first linearly polarized mode, from the horizontal port to the common waveguide. A portion of the vertical branch waveguide may overlap a portion of the cylindrical common waveguide. A septum may span the vertical branch waveguide proximate to the overlapping portions of the vertical branch waveguide and the common waveguide. A rectangular symmetry cavity may be opposed to the horizontal branch waveguide.

Abstract: An antenna may include a primary reflector having a ring focus; a feed body along an axis of the primary reflector, the feed body including a circular waveguide coaxial with the axis of the primary reflector; a sub-reflector disposed facing an end of the circular waveguide; and a generally cylindrical stem extending from a center of the sub-reflector into the circular waveguide to form a section of annular waveguide. A sub-reflector support may mechanically connect a perimeter of the sub-reflector and an outside surface of the feed body. The sub-reflector, the stem, and the feed body may be collectively configured to couple microwave energy between the annular waveguide and the primary reflector.

Abstract: A polarization converter may include an annular waveguide comprising an inner conductor having an outer surface and an outer conductor having an inner surface coaxial with the outer surface of the inner conductor. A plurality of loading structures may be disposed within the annular waveguide to form a plurality of regions within the annular waveguide including an alternating sequence of high phase shift regions and low phase shift regions along a direction of propagation of an electromagnetic wave. The plurality of loading structures may be configured to introduce a predetermined relative phase shift between orthogonally polarized first and second components of the electromagnetic wave for a predetermined operating frequency band. The plurality of loading structures may be further configured to suppress propagation of one or more higher order modes in the annular waveguide over the operating frequency band.

Abstract: An ortho-mode transducer may include a common waveguide terminating in a common port. A horizontal branch waveguide may terminate in a horizontal port. The horizontal branch waveguide may couple a first linearly polarized mode from the horizontal port to the common waveguide. The horizontal branch waveguide may comprise one or more ridged waveguide segments. A vertical branch waveguide may terminate in a vertical port opposed to the horizontal port. The vertical branch waveguide may couple a second linearly polarized mode from the vertical port to the common waveguide, the second linearly polarized mode orthogonal to the first linearly polarized mode.

Abstract: A feed network may include a cylindrical common waveguide terminating in a common port and an orthomode transducer having a first port for coupling a first linearly polarized mode to the cylindrical common waveguide and a second port for coupling a second linearly polarized mode to the cylindrical common waveguide, the second linearly polarized mode orthogonal to the first linearly polarized mode. A filter-polarizer element may be disposed within the cylindrical common waveguide. The filter-polarizer element may be rotatable about an axis of the cylindrical common waveguide. The filter-polarizer element may be configured to cause a predetermined relative phase shift between a first signal and a second signal propagating in the cylindrical common waveguide. The filter-polarizer element may be further configured to suppress propagation of at least one undesired mode in the cylindrical common waveguide.

Abstract: An ortho-mode transducer may include a cylindrical common waveguide terminating in a common port, a rectangular vertical branch waveguide in-line with the cylindrical common waveguide and terminating in a vertical port, and a rectangular horizontal branch waveguide normal to the common waveguide and terminating in a horizontal port. The vertical branch waveguide may be configured to couple a first linearly polarized mode from the vertical port to the common waveguide. The horizontal branch waveguide may be configured to couple a second linearly polarized mode, orthogonal to the first linearly polarized mode, from the horizontal port to the common waveguide. A portion of the vertical branch waveguide may overlap a portion of the cylindrical common waveguide. A septum may span the vertical branch waveguide proximate to the overlapping portions of the vertical branch waveguide and the common waveguide. A rectangular symmetry cavity may be opposed to the horizontal branch waveguide.

Abstract: There is disclosed an ortho-mode transducer fabricated as a single piece. The ortho-mode transducer may include a first surface having an aperture defining a common port, a second surface having an aperture defining a vertical port, and a third surface having an aperture defining a horizontal port. The second and third surfaces may be essentially parallel and normal to the first surface. A common waveguide may coupled to the common port, the common waveguide supporting orthogonal vertical and horizontal modes. A vertical branching waveguide may couple the vertical mode between the vertical port and the common waveguide while rejecting the horizontal mode. A horizontal branching waveguide may couple the horizontal mode between the horizontal port and the common waveguide while rejecting the vertical mode.

Abstract: An ortho-mode transducer may include an annular common waveguide defined by an outside surface of an inner conductor and an inside surface of an outer conductor, the outside surface and the inside surface concentric about a waveguide axis. A first port may couple a first TE11 mode to the annular common waveguide. A second port may couple a second TE11 mode to the annular common waveguide, the second TE11 mode orthogonal to the first TE11 mode. A TEM probe may suppress resonance of a TEM mode within the annular common waveguide.

Abstract: There is disclosed a linear polarization to circular polarization converter. An outside surface of an inner conductor may be coaxial with the inside surface of an outer conductor. First and second diametrically opposed fins may extend outward from the outer surface of the inner conductor. Each of the first and second fins may include a conductive fin and a dielectric fin.

Abstract: There is disclosed an ortho-mode transducer. An annular common waveguide may be defined by an outside surface of an inner conductor and an inside surface of an outer conductor, the outside surface and the inside surface concentric about a waveguide axis. A first port may couple a first TE11 mode to the annular common waveguide. A second port may couple a second TE11 mode to the annular common waveguide, the second TE11 mode orthogonal to the first TE11 mode. A first back-short may be disposed adjacent to the first port. A second back-short may be disposed on the outside surface of the inner conductor between the first port and the second port.

Abstract: There is disclosed a feed network including a circular common waveguide having an axis and terminating in a common port and a first port for coupling a first linearly polarized mode to the circular common waveguide. A phase shifting element may be disposed within the circular waveguide. The phase shifting element may be adapted to cause a predetermined phase shift between a first signal and a second signal propagating in the common waveguide. The phase shifting element may be rotatable about the axis of the common waveguide.

Abstract: There is disclosed a linear polarization to circular polarization converter. An outside surface of an inner conductor may be coaxial with the inside surface of an outer conductor. First and second diametrically opposed conductive fins may extend outward from the outer surface of the inner conductor. First and second dielectric fins may be interlocked with the first and second conductive fins, respectively.

Abstract: A wide-band feed for a reflector antenna that provides a sum and a difference radiation pattern for tracking and for the transmission or reception of data. The feed utilizes two coaxially located, coaxial waveguides. The inner coaxial waveguide supports propagation of the TE11 mode and produces a sum radiation pattern. The outer coaxial waveguide supports propagation of the TE21 mode and produces a difference radiation pattern. The dimensions of the inner and outer waveguides are selected such that the dispersions of the TE11 mode in the inner coaxial waveguide and the TE21 mode in the outer coaxial waveguide are the same. Coaxial chokes located near the open ends of the wave guide modify the impedance match to free space of the fields within the waveguides and modify the radiation patterns generated by the waveguides. Probes within the waveguides generate the respective modes.