Abstract: A system for properly illuminating a toll collection zone without illuminating any areas outside the toll collection zone in which vehicles may be found, while minimizing lost tolls due to shadowing of shorter vehicles by taller vehicles. In one embodiment, a linear array antenna is configured to illuminate a rectangular collection zone from a point offset from the center of the roadway. The linear array antenna is configured to produce an asymmetric antenna pattern providing RF illumination over the rectangular collection zone sufficient for reliable reading of vehicle RF tags in the collection zone, and which also minimizes spillover of RF power outside the collection zone.

Abstract: A system for properly illuminating a toll collection zone without illuminating any areas outside the toll collection zone in which vehicles may be found, while minimizing lost tolls due to shadowing of shorter vehicles by taller vehicles. In one embodiment, a linear array antenna is configured to illuminate a rectangular collection zone from a point offset from the center of the roadway. The linear array antenna is configured to produce an asymmetric antenna pattern providing RF illumination over the rectangular collection zone sufficient for reliable reading of vehicle RF tags in the collection zone, and which also minimizes spillover of RF power outside the collection zone.

Abstract: The present invention relates to active electronically scanned array antennas. A thin, low cost design is provided by coupling electromagnetic energy into periodically driven long slots (205) using circulators with integrated probes (107). The long slots (205) are formed as grooves (114) in a conductive base plate (103), each groove (114) bracketed on both sides by conductive strips (108). The circulators with integrated probes (107) are installed between the conductive strips (108) and the base plate (103), to reduce fabrication costs of the machined parts and to facilitate the making of connections between the circulators and the antenna electronics. The probes (128) protrude partway into the slots (205) and provide coupling to waves propagating in free space.

Abstract: The present invention relates to active electronically scanned array antennas. A thin, low cost design is provided by coupling electromagnetic energy into periodically driven long slots (205) using circulators with integrated probes (107). The long slots (205) are formed as grooves (114) in a conductive base plate (103), each groove (114) bracketed on both sides by conductive strips (108). The circulators with integrated probes (107) are installed between the conductive strips (108) and the base plate (103), to reduce fabrication costs of the machined parts and to facilitate the making of connections between the circulators and the antenna electronics. The probes (128) protrude partway into the slots (205) and provide coupling to waves propagating in free space.

Abstract: An antenna system includes an array of notch radiators, arranged in aligned rows on longitudinal axes to define a series of troughs between adjacent notch radiator rows within an aperture area, each notch radiator including a tip region. A plurality of surface/traveling wave suppressors fabricated of microwave energy absorbing material is disposed in the troughs, so that a longest suppressor dimension is transverse or nearly transverse to the array face and so that a suppressor surface is transverse or nearly transverse to the longitudinal axes.

Abstract: An antenna system includes an array of notch radiators, arranged in aligned rows on longitudinal axes to define a series of troughs between adjacent notch radiator rows within an aperture area, each notch radiator including a tip region. A plurality of surface/traveling wave suppressors fabricated of microwave energy absorbing material is disposed in the troughs, so that a longest suppressor dimension is transverse or nearly transverse to the array face and so that a suppressor surface is transverse or nearly transverse to the longitudinal axes.

Abstract: A very low reflection transition with tightly controlled variability between a rectangular coaxial transmission line and a microstrip transmission line. The microstrip ground plane is extended under the transition region to form the transition ground plane. The upper portion of the dielectric of the rectangular coaxial transmission line is removed at the transition region, together with the upper portion of the center conductor. The spacing between the transition center conductor and the ground plane is reduced in relation to the spacing between the rectangular coaxial line center conductor and outer conductive shield. A tuning cavity is formed in the transition ground plane beneath the transition center conductor.