Advanced Packaging of Conformal Wideband Antennas for UAVs With Optimized RCS Reduction

This article presents an advanced packaging architecture for conformal wideband antennas intended for unmanned aerial vehicles (UAVs), with specific emphasis on Vehicle-to-Everything (V2X) connectivity and radar cross-section (RCS) reduction. The proposed design employs a cavity-embedded Vivaldi antenna, where conformal behavior is achieved through a curvature-matched machined cylindrical cavity and Rohacell support. The antenna is engineered to operate across 2-18 GHz, providing wideband coverage suitable for multi-functional UAV communication and sensing. The packaged structure enhances the realized gain (5-12 dBi across the band) and achieves a significant RCS reduction down to –18 dBsm, facilitating improved survivability and reduced detectability in radar-monitored environments. Fabricated on a RO4350B substrate, the antenna maintains a compact footprint of 0.45λ₀ × 0.34λ₀ × 0.0016λ₀ at 2 GHz and is optimized for aerodynamic compatibility with UAV fuselage contours. Comprehensive full-wave simulations and measurements validate the performance of the integrated antenna–cavity assembly in terms of impedance bandwidth, radiation characteristics, and scattering behavior. The presented packaging approach demonstrates a robust pathway for UAV-centric wideband antenna integration, offering improved radiation stability, reduced signature, and compatibility with next-generation V2X communication systems.