Abstract: A deployable aperture reflector for use in antennas to reflect an RF electromagnetic signal of a predetermined signal frequency band includes a deployable aperture structure deployable between a stowed aperture configuration and a deployed aperture configuration. The aperture structure includes a plurality of rigid members connecting to one another to support an RF reflective assembly when in the deployed aperture configuration. The RF reflective assembly includes a plurality of faceted cells adjacent one another that form an assembly mechanical shape approximating an optimal desired electrical surface shape. Each faceted cell includes at least one layer carrying RF resonant elements thereon that electrically compensate a difference between the assembly mechanical shape and the optimal desired electrical surface shape.

Abstract: An electromagnetic bandgap device is mountable on a RF disturbing structure of an antenna to minimize signal field disturbance imparted thereby. The RF disturbing structure is oriented in a direction substantially parallel to a path of travel of an antenna signal and located within a field covered by the signal transmitted by a feed. The bandgap device comprises a plurality of RF perturbing elements connected to the RF disturbing structure and spaced apart from one another in the direction substantially parallel to the signal path. The perturbing elements are positioned, configured and sized to direct a disturbed portion of the signal away therefrom to reduce field disturbance generated by the disturbed signal portion interacting with an undisturbed portion of the antenna signal.

Abstract: A device for modifying electromagnetic illumination of a reflector aperture defined by a reflector surface is mounted in front of the reflector aperture in a spaced apart relationship relative to the reflector surface. The device at least partially covers the reflector aperture and provides an illumination control means for at least partially and selectively modifying electromagnetic illumination of the reflector aperture. The device may include a membrane-like substrate that is substantially transparent to electromagnetic radiation. A supporting member may support the substrate in the spaced apart relationship relative to the reflector surface.

Abstract: A multimode horn used to feed an antenna includes a generally tapered wall for transmitting and/or receiving an electromagnetic signal there through. The wall flares radially outwardly from a throat section to an aperture and defines an internal surface having a plurality of discontinuities. The geometry of the discontinuities are configured and sized to alter the dominant mode, which conveys the communications signal, into a higher order symmetrical mode content to achieve a balance between a plurality of communications performance parameters of the antenna over a pre-determined frequency range of the signal. The discontinuities are also designed to match the horn impedance for the modes of the communications signal and for an asymmetrical mode content of a simultaneously propagating tracking signal.

Abstract: An electromagnetic bandgap device is mountable on a RF disturbing structure of an antenna to minimize signal field disturbance imparted thereby. The RF disturbing structure is oriented in a direction substantially parallel to a path of travel of an antenna signal and located within a field covered by the signal transmitted by a feed. The bandgap device comprises a plurality of RF perturbing elements connected to the RF disturbing structure and spaced apart from one another in the direction substantially parallel to the signal path. The perturbing elements are positioned, configured and sized to direct a disturbed portion of the signal away therefrom to reduce field disturbance generated by the disturbed signal portion interacting with an undisturbed portion of the antenna signal.

Abstract: A device for modifying electromagnetic illumination of a reflector aperture defined by a reflector surface is mounted in front of the reflector aperture in a spaced apart relationship relative to the reflector surface. The device at least partially covers the reflector aperture and provides an illumination control means for at least partially and selectively modifying electromagnetic illumination of the reflector aperture. The device may include a membrane-like substrate that is substantially transparent to electromagnetic radiation. A supporting member may support the substrate in the spaced apart relationship relative to the reflector surface.

Abstract: A steerable antenna allows transmission of an electromagnetic signal between a fixed feed source or an image thereof and a target moving within an antenna coverage region. The peak gain of the signal beam varies as a function of the target position following a desired signal gain profile. The antenna includes a reflector defining a reflector surface for reflecting the signal between the feed source or its image and the target. The reflector surface defines a focal point, a center point and a normal axis perpendicular to the reflector surface at the center point. The normal axis and the feed axis intersecting the center point and the feed source or its image define a common offset plane. An elevation rotary actuator rotates the reflector about a rotation axis perpendicular to the offset plane adjacent to the center point so that the antenna provides a nominal signal gain profile over the coverage region.

Abstract: A steerable antenna allows transmission of an electromagnetic signal between a fixed feed source or an image thereof and a target moving within an antenna coverage region. The peak gain of the signal beam varies as a function of the target position following a desired signal gain profile. The antenna includes a reflector defining a reflector surface for reflecting the signal between the feed source or its image and the target. The reflector surface defines a focal point, a center point and a normal axis perpendicular to the reflector surface at the center point. The normal axis and the feed axis intersecting the center point and the feed source or its image define a common offset plane. An elevation rotary actuator rotates the reflector about a rotation axis perpendicular to the offset plane adjacent to the center point so that the antenna provides a nominal signal gain profile over the coverage region.

Abstract: A steerable antenna system for transmitting and/or receiving an electromagnetic signal to a relatively moving target includes a hyperbolic subreflector secured to a frame rotatably mounted on a support structure via a first motor and a feed source located at a first focus of the subreflector for illuminating the same. The source, fixed to the structure, has a source axis pointing at the subreflector. A parabolic reflector having a focus in common with the second focus of the subreflector to transfer the signal between the same and a planar reflector is secured to the frame and has a beam axis. The planar reflector having a normal axis intersecting the beam axis with an angle is rotatably mounted on the frame via a second motor to transfer the signal between the parabolic reflector and the target. The system may include a controller connected to the motors to control the system to steer at the target anywhere within a full spherical angular range.

Abstract: A multimode horn used to feed an antenna includes a generally conical wall for transmitting and/or receiving an electromagnetic signal there through. The wall flares radially outwardly from a throat section to an aperture and defines an internal surface having a plurality of discontinuities formed thereon and made out of electrically conductive material. The geometry of the discontinuities are configured and sized for altering the higher order mode content of the signal to achieve a balance between a plurality of performance parameters of the antenna over at least one pre-determined frequency range of the signal. The discontinuities are selected from the group consisting of local smooth profile, step, corrugation and choke.

Abstract: A multimode horn used to feed an antenna includes a generally hollowed conical structure for transmitting and/or receiving an electromagnetic signal there through. The structure flaring radially outwardly from a throat section to an aperture has a pre-determined size and an internal wall with a plurality of discontinuities for altering the mode content of the signal to achieve a balance between a plurality of performance parameters of the antenna over a pre-determined frequency range of the signal. At least one performance parameter is from the group of horn on-axis directivity, horn pattern beamwidth, antenna illumination edge-taper, antenna illumination profile and antenna spill-over losses. The discontinuities are a combination of different local smooth profiles and/or steps and/or corrugations and/or chokes.