Feeding of a wideband Superstrate-Enhanced Substrate Loaded Array

In a recent paper, the authors presented a Superstrate-Enhanced Substrate-Loaded Array (SESLA) for scanning array systems demanding extreme (> 10 : 1) bandwidth. For proper operation, the SESLA requires balanced feeding, a significant challenge given its large bandwidth. In this paper a version of the SESLA with an integrated feed is presented. The design uses a stripline-based Marchand balun, allowing interface with a 50Ω unbalanced line. The optimized version of the array is demonstrated to operate across a 13.9 : 1 bandwidth under broadside scan (VSWR <; 2.4) and across a 13.3 : 1 bandwidth (VSWR <; 3) when scanned to 45° in the E- and H-planes.