A smart millimeter-wave base station for 6G application based on programmable metasurface.

The evolution of programmable metasurfaces has yielded many exciting electromagnetic (EM) phenomena and applications in both communities of physical and information sciences. Programmable metasurfaces, also known as reconfigurable intelligent surfaces or intelligent reflecting surfaces in wireless communications, have played important roles in enhancing signal coverage and transmission quality, and in building an artificially controlled communication environment. However, most of the realistic implementations are designed in the sub-6G band with a small array scale and 1-bit phase control ability, making the performance improvement not marvelous compared with the traditional solutions.

3,3,4,4-Tetra-fluoro-1-[2-(3,3,4,4-tetra-fluoro-pyrrolidin-1-yl)phen-yl]pyrrolidine.

The asymmetric unit of the title compound, C(14)H(12)F(8)N(2), contains one tetra-fluoro-pyrrolidine system and one half-mol-ecule of benzene; the latter, together with a second heterocyclic unit, are completed by symmetry, with a twofold crystallographic axis crossing through both the middle of the bond between the C atoms bearing the heterocyclic rings and the opposite C-C bonds of the whole benzene mol-ecule. The pyrrolidine ring shows an envelope conformation with the apex at the N atom. The dihedral angle between the least-squares plane of this ring and the benzene ring is 36.

3,3,4,4-Tetra-fluoro-2,3,4,5-tetra-hydro-1,6-benzodioxocine-8-carbaldehyde.

In the title compound, C(11)H(8)F(4)O(3), the eight-membered dialk-oxy ring adopts a highly puckered conformation. In the crystal, mol-ecules are linked by weak C-H⋯O inter-actions.