Broadband Wide-Scanning Large-Curvature Cylindrical Conformal Dipole Array Antenna With Low-Scattering Characteristics

A 1–2-GHz wide-scanning cylindrical conformal array antenna with a large curvature is proposed in this article. A novel dipole element with integrated feeding balun is proposed, featuring a bending angle of 30° in the E-plane, and a metal wall is employed to suppress common-mode resonance. Optimizations based on a cylindrical conformal subarray further improve the beam scanning ability. According to the analyses, the element large-curvature bending suppresses the edge element impedance mismatch and array beam pointing deviation. In addition, the cylindrical contour of the proposed array leads to an obvious scattering cross section reduction (SCSR) compared to flat metal ground, and the co-polarized (co-pol) SCSR is enlarged by in-band absorptions of array elements. To increase the cross-polarized (cr-pol) SCSR, a cr-pol absorbing structure terminated by a resistor is designed in the flexible impedance matching layer of a polyimide (PI) film. Consequently, the proposed conformal dipole array antenna achieves both notable co-/cr-pol in-band monostatic SCSRs, as well as the beam scanning in the E-/H-planes within ±75°/±60°. The correctness of the proposed design method is verified by the experiment on an
$8\times 6$
cylindrical conformal array prototype, and the measured results demonstrate the broadband wide-scanning performances and low-scattering characteristics.