Abstract: A brake control system of the present disclosure includes an accelerometer coupled to an axle. A brake control unit is configured to receive an axle acceleration signal indicative of an axle acceleration from the accelerometer, and decrease a braking command pressure in response to the axle acceleration being greater than a threshold acceleration value.

Abstract: A reflectarray antenna system includes an antenna feed configured to at least one of transmit and receive a wireless signal occupying a frequency band. The system also includes a reflector having a reflectarray. The reflectarray includes a plurality of reflectarray elements, where each of the reflectarray elements includes a dipole element. The dipole element of at least a portion of the plurality of reflectarray elements comprises a crossed-dipole portion and a looped-dipole portion. The plurality of reflectarray elements can be configured to selectively phase-delay the wireless signal to provide the wireless signal as a coherent beam.

Abstract: A reflectarray antenna includes a plurality of antenna conductors patterned on two or more planar surfaces. The antenna conductors include a first set of antenna conductors having a geometric arrangement to beamform and radiate a first wireless signal over a first frequency band. A second set of antenna conductors have a geometric arrangement to beamform and radiate a second wireless signal over a second frequency band that is distinct from the first frequency band. The first set of antenna conductors are formed on the two or more planar surfaces to enable operation at the first frequency band. The second set of antenna conductors are formed on the two or more planar surfaces to enable the second frequency band.

Abstract: A planar reflectarray system provides for bandwidth broadening by employing a tunable (amplitude and phase) feed array. The tunable feed array is adjustable in amplitude and phase to compensate for aberrations by enabling feed re-focusing and field matching. The techniques modestly increase the size of the feed array and use active tuning to effectively correct for de-focusing when operating reflectarrays at frequencies away from the tuned center frequency.

Abstract: A reflectarray antenna includes a plurality of antenna conductors patterned on two or more planar surfaces. The antenna conductors include a first set of antenna conductors having a geometric arrangement to beamform and radiate a first wireless signal over a first frequency band. A second set of antenna conductors have a geometric arrangement to beamform and radiate a second wireless signal over a second frequency band that is distinct from the first frequency band. The first set of antenna conductors are formed on the two or more planar surfaces to enable operation at the first frequency band. The second set of antenna conductors are formed on the two or more planar surfaces to enable the second frequency band.

Abstract: A planar reflectarray system provides for bandwidth broadening by employing a tunable (amplitude and phase) feed array. The tunable feed array is adjustable in amplitude and phase to compensate for aberrations by enabling feed re-focusing and field matching. The techniques modestly increase the size of the feed array and use active tuning to effectively correct for de-focusing when operating reflectarrays at frequencies away from the tuned center frequency.

Abstract: A reflectarray antenna system includes an antenna feed configured to at least one of transmit and receive a wireless signal occupying a frequency band. The system also includes a reflector having a reflectarray. The reflectarray includes a plurality of reflectarray elements, where each of the reflectarray elements includes a dipole element. The dipole element of at least a portion of the plurality of reflectarray elements comprises a crossed-dipole portion and a looped-dipole portion. The plurality of reflectarray elements can be configured to selectively phase-delay the wireless signal to provide the wireless signal as a coherent beam.

Abstract: One embodiment describes a reflectarray antenna system. The system includes an antenna feed configured to at least one of transmit and receive a wireless signal occupying a frequency band. The system also includes a reflector comprising a reflectarray. The reflectarray includes a plurality of reflectarray elements, where each of the reflectarray elements includes a dipole element. The dipole element of at least a portion of the plurality of reflectarray elements comprises a crossed-dipole portion and a looped-dipole portion. The plurality of reflectarray elements can be configured to selectively phase-delay the wireless signal to provide the wireless signal as a coherent beam.

Abstract: One embodiment describes a reflectarray antenna system. The system includes an antenna feed configured to at least one of transmit and receive a wireless signal occupying a frequency band. The system also includes a reflector comprising a reflectarray. The reflectarray includes a plurality of reflectarray elements, where each of the reflectarray elements includes a dipole element. The dipole element of at least a portion of the plurality of reflectarray elements comprises a crossed-dipole portion and a looped-dipole portion. The plurality of reflectarray elements can be configured to selectively phase-delay the wireless signal to provide the wireless signal as a coherent beam.

Abstract: A method and apparatus for improving polarization purity of a reflectarray that eliminates cross-coupling between orthogonal polarizations. A first embodiment of the present invention is a grid layer that separates two layers of orthogonal dipole elements. A second embodiment of the present invention is a reflectarray having an array of dipole elements in which each dipole element is gridded to prevent cross-coupling between orthogonal polarizations.

Abstract: A reflectarray antenna for achieving increased dynamic phase range has a plurality of dipole elements positioned across the antenna surface. The elements include a single dipole element having a predetermined length that is approximately proportional to the dynamic phase range through which the first dipole element can reflect. The elements also include a coupled dipole element which comprises a longer dipole and a shorter dipole. The longer dipole and the shorter dipole are positioned on the reflectarray surface such that they are spaced a predetermined distance apart.

Abstract: A method for shaping reflected radio frequency signals includes geometrically shaping a reflector surface of an antenna to focus the beam, and reflectively shaping the reflector surface with phasing elements that emulate geometric shaping to configure the beam to a predetermined shape. In the preferred embodiment, the antenna comprises a geosynchronous satellite antenna conveying signals from a wave guide horn to or from a predetermined geographic area on earth. The use of a parabolic-approaching surface of reflectarray phasing elements for shaping the beam substantially improves the beam pattern bandwidth over the performance of previously known shaped beam reflectarrays.