Wideband Wide-Scanning Planar Triangular-Lattice Phased Array With Substrate-Integrated Cavity-Backed U-Slot Patches

A compact wideband and wide-scanning planar triangular-lattice phased array is proposed. The proposed element is a U-slot microstrip antenna surrounded by a substrate-integrated cavity (SIC) structure fed by a 50 Ω coaxial cable. The scan blindness is effectively shifted out of the operation band as the SIC structure obstructs the surface wave and mutual coupling. The proposed array is arranged in a triangular lattice with fewer elements than a rectangular one. A 4×8 planar array prototype is fabricated and measured over X-band. The antenna provides a bandwidth of over 30% frequency range under ±60° scanning in all azimuth planes.