Key Technologies in 6G SAGS IoT: Shape-Adaptive Antenna and Radar-Communication Integration

6G will integrate the physical and digital worlds, and ubiquitous 6G service will seamlessly reach users worldwide. The concept of space-air-ground integrated networks has been proposed to integrate these three subnetworks homogenously. However, the ocean accounts for about 71 percent of the global area, and underwater networks play an important role in the defense field and the construction of the intelligent marine Internet of Things. To seize future development opportunities, this article introduces the space-air-ground-sea integrated network (SAGSIN) and related technologies, including the shape-adaptive antenna and radar-communication integration. The proposed shape-adaptive antenna is made of flexible materials, thereby allowing its physical shape to be changed in real time and for a specific radiation beam to be formed according to the functional requirements. The requirements and feasibility of radar communication integration are also analyzed comprehensively, and a detailed analysis and simulation verification are carried out for UAV detection.