Investigation of a Low-Profile Ultra-Wideband Tightly Coupled Dipole Array

The investigation of a low-profile wideband and two-dimensional wide-scanning tightly coupled dipole array (TCDA) is presented. The array is designed without wide angle impedance matching (WAIM) layer for the sake of low-profile and a compact wideband integrated balun is implemented to feed the array aperture. Parasitic rectangular strips etched on each side of the dipole are utilized to improve the radiation performances in the H-plane, which is orthogonal to the current excited direction that is tightly coupled. An 8 × 8 planar prototype array was fabricated and measured. The array is able to achieve 4:1 impedance bandwidth with active VSWR <; 3.1 in the E-plane while scanning up to ±60° and active VSWR <; 3.0 in the H-plane while scanning up to ±40°, respectively. Meanwhile, the measured cross polarization level of the prototype is less than -20 dB along principal planes scanning.