Extremely large-scale multiple-input-multiple-output (XL-MIMO) is promising to meet the high rate requirements for future 6G. To realize efficient precoding, accurate channel state information essential. Existing estimation algorithms with low pilot overhead heavily rely on sparsity in angular domain, which achieved by classical far-field planar-wavefront assumption. However, due non-negligible...

According to the electromagnetic uniqueness theorem, radiation behavior of an antenna under test (AUT) can be recovered from measurements two tangential components its radiated fields on enclosing surface. In practice, conducted in radiating near-field (NF) AUT utilize probe antennas finite size. Thus, instead discrete field values, spatially blurred signals are acquired. The influence compensa...

Reinforced concrete (RC) frame structures with open first stories and masonry infill walls at the upper are very common in seismic areas. Under strong earthquakes, most of energy dissipation demand imposed by earthquake concentrates story, this eventually leads building to collapse. A efficient cost-effective solution for upgrading type structure consists installing hysteretic dampers story. Th...