Analysis and design of connected slot arrays with artificial dielectrics

Abstract

Connected arrays of slots loaded with artificial dielectric layers have been proposed to realize wideband phased arrays with large scan capability. The role of the artificial dielectric superstrate is to provide a wide angle impedance matching transformation from the impedance at the feeding port of the unit cell to the free space impedance. This wideband transformer also reduces the negative effects of the ground plane on the impedance matching. Unlike dielectric superstrates, artificial dielectrics can avoid the propagation of surface waves and the occurrence of scan blindness over very wide scan volumes and large frequency ranges. The analytical method used for the modeling of the unit cell is described. The analysis is based on closed-form expressions for both the connected array and the artificial dielectric, thus it can be used to simulate the main array parameters with minimal computation resources. The method is then used to design a 5:1 connected array with scanning capability up to 60 degrees in all azimuthal directions.