Frequency Selective Surface Network for In-Phase Ground Plane Reflections in Tightly Coupled Dipole Arrays

There is strong interest in improving the performance of Perfectly Electric Conductor (PEC) backed arrays to achieve wider bandwidths and near theoretical gain. This is challenging due to the well-known size-gain-bandwidth compromise. Indeed, the presence of a ground plane has limited antenna bandwidth until the development of Tightly Coupled Dipole Arrays (TCDA). TCDAs have allowed optimal bandwidth by reducing the Bode-Fano limits. In this paper, we introduce an approach to further increase the bandwidth using Frequency Selective Surfaces (FSS). The integration of such FSS network within a dual-polarized TCDA led to a 29:1 impedance bandwidth and scanning up to 60° at $\text{VSWR} \ < \ 3$ (E-Plane) with an average efficiency of 80%. This large bandwidth was achieved by suppressing ground plane resonances.