Circuit model based optimization of ultra-wideband arrays

Circuit models are proposed as an optimization tool for designing ultra-wideband tightly coupled arrays. Past approaches have provided rudimentary equivalent circuits for the current sheet array (CSA) by modeling the capacitively coupled dipoles using simple lumped elements. In this paper, we extend the model to include higher order circuits (lumped and distributed) around the wideband antenna feed. The optimized antenna is shown to deliver as much as 5.7:1 impedance bandwidth, achieved by adding a series inductor and a shunt capacitor to the feed of the coupled dipole array. Corresponding impedance curves obtained via the full wave simulation are in good agreement with the equivalent circuit.