A Dual-Band Dual-Mode Aperture-Shared Conformal Array with Wideband and High gain for UAV-Based Wide-Coverage Communication and Multi-Polarization Sensing

To address the demand for integrated sensing and communication (ISAC) on unmanned aerial vehicle (UAV) platforms, this paper presents a conformal aperture-shared dual-band dual-mode antenna system. A shared-aperture radiating element is developed to integrate lower-band communication in the dipole mode and higher-band sensing in an embedded dual-Vivaldi bidirectional end-fire mode within the same physical aperture. Different from conventional dual-Vivaldi configurations, a modified feeding scheme with a shared tapered transition and simplified excitation structure is introduced, which lowers the minimum operating frequency, improves the realized gain, and enables higher-band array realization under the element-spacing constraint imposed by the lower band. Furthermore, a distributed fuselage-wing conformal array architecture is developed for UAV deployment, where multiple subarrays are coordinated to simultaneously provide wide-coverage communication and directional multi-polarization sensing under limited platform space. A prototype was fabricated and measured. Experimental results show the two modes achieve relative impedance bandwidths of 105% and 103.9%, with peak gains of 9.06 dBi and 14.23 dBi, respectively. The dipole mode provides 76° × 360° quasi-omnidirectional coverage, while the Vivaldi mode supports bidirectional radiation with horizontal, vertical and ±45° linear polarizations. The proposed antenna system therefore offers a compact and effective solution for UAV-based ISAC applications.