Evolution of wide band array designs

For wide array antennas, four types of radiators (array elements) can be considered. These include the long Vivaldi tapered notch, flared dipole (“bunny-ear”), connected dipoles or long slots (“Thumbtack” for dual-pol), and low profile elements backed by high impedance magnetic ground plane. Phased array is a periodic structure characterized by certain band pass features defined by its lattice and radiator geometry. However, radiator design is actually a “transformer” design aimed to match TR module and electronics´ low impedance (25~50 ohms) to free space´s 377 ohm wave impedance with minimum reflection in a large array. This impedance ladder can be partitioned in different ways, resulting in different radiator designs. An overview on the evolution of wide band radiators and array designs at Raytheon SAS is presented.