可转向天线赋能空天地一体化网络:基础原理、关键挑战与未来展望OA

Space-air-ground integrated networks(SAGINs)are expected to serve as an essential infrastructure for ubiquitous connectivity,wide-area coverage,integrated sensing,and intelligent services in future sixth-generation wireless networks.However,significant differences among the space,aerial,and ground segments in terms of coverage range,mobility patterns,propagation environments,payload capabilities,and service requirements make it difficult for fixed-boresight or fixed-sector antenna systems to continuously provide effective directional support for dynamic access,relay,and backhaul links.To address this issue,this article presents a systematic discussion of rotatable antenna(RA)-empowered SAGINs.By flexibly adjusting the three-dimensional boresight orientation of antennas through mechanical rotation,electronic reconfiguration,or a hybrid mechanism without changing their physical positions,RA introduces an additional spatial degree of freedom for directional adaptation,thereby improving directional gain,extending three-dimensional coverage,enhancing the stability of access,relay,and backhaul links,and supporting cross-segment collaborative services.We first introduce the fundamental principles,typical hardware architectures,and radiation-pattern characteristics of RA.Then,we establish communication-link,sensing-task,and cross-segment service-path models for RA-empowered SAGINs,with a focus on analyzing the role of boresight control in access,relay,backhaul,and sensing coordination.We further elaborate on key challenges,including channel acquisition and predictive tracking,joint boresight control and access/handover coordination,multi-segment resource management,deployment tradeoffs,and practical implementation,and discuss potential solutions.Finally,prototype verification for air-ground collaborative communication and sensing and a simulation case study on dynamic low-Earth-orbit satellite access are presented to illustrate the application prospects of RA in intelligent,highly resilient,and cost-efficient SAGINs.