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:
An antenna array includes a plurality of radiating elements disposed on a layer that is situated above an egg crate structure that is formed of interconnected dielectric panels. In some embodiments, balun circuitry is disposed on at least some of the dielectric panels of the egg crate structure for use in feeding corresponding radiating elements of the array in a balanced manner. Ground plane blocks may also be coupled to some or all of the dielectric panels to provide circuit shielding and/or to form a ground plane for the array antenna.
Abstract:
An antenna array includes a plurality of radiating elements disposed on a layer that is situated above an egg crate structure that is formed of interconnected dielectric panels. In some embodiments, balun circuitry is disposed on at least some of the dielectric panels of the egg crate structure for use in feeding corresponding radiating elements of the array in a balanced manner. Ground plane blocks may also be coupled to some or all of the dielectric panels to provide circuit shielding and/or to form a ground plane for the array antenna.