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 $8 \times8$ planar prototype array was fabricated and measured. The array is able to achieve 4:1 impedance bandwidth with active VSWR $\lt/p\gt\lt3.1$ in the E-plane while scanning up to ±60° and active VSWR $\lt/p\gt\lt3.0$ in the H-plane while scanning up to ±45°, respectively. Meanwhile, the measured cross polarization level of the prototype is less than −20 dB along principal planes scanning.