Wideband Wide-Scanning Phased Array in Triangular Lattice With Electromagnetic Bandgap Structures

A phased array in a triangular lattice, with a large element spacing, wide band, and wide scan angle, is investigated in this letter. The array is designed based on a connected backed-cavity antenna element. Scan blindness is observed for this triangular lattice array when the beam scans in the E-plane due to large element spacing, which provides a suitable propagation condition for the leaky surface waves in the array aperture. Therefore, compact electromagnetic bandgap (EBG) structures are loaded in the array element to suppress the leaky surface waves and then remove the E-plane scan blindness for the largest impedance bandwidth. The bandwidths close to the theoretical values are achieved as the beam is scanned in the E- and H-planes, for the given element spacing. The validity of design is verified by fabricating a 13 × 5 prototype, the measured results are in good agreement with the full-wave simulations.