A 9:1 Bandwidth Low-Profile Tightly Coupled Dipole Array with Compact Matching Network

An ultra-wideband low-profile tightly coupled dipole array is proposed in this paper. The antenna element is fed through a folded divider to achieve a low-profile characteristic. A Marchand balun is employed to accomplish the transformation of unbalanced feeding ports and unmatched impedance, simultaneously. A resistive sheet (
$200\Omega$
/square) is utilized to widen the operation bandwidth. Besides, the element contains a wide angle impedance matching layer (WAIM) for a broader scan angle. Simulation results show that this antenna can operate within a 9:1 bandwidth (2-18GHz) with
$\text{VSWR} < 3.3$
, and ±45° scan in E- and H-plane with a relatively high radiation efficiency. The overall profile is 12.4mm (
$0.74\lambda_{\text{high}}$
), which makes the antenna suitable for the application of special radar platforms.