For the receiver, broad bandwidth, low noise and high linearity are required. Among them are the linearity of transmitters, broad bandwidth and high output power. High-speed radio hardware of wireless communications needs several technical aspects to be considered. Although, some applications can be supported by the present mobile networks, it is clear that we need to increase the operating frequency from the currently used 4G and experimental 5G bands to the terahertz bands (0.1–10 THz) of 6G to satisfy mobile broadband communication in the future. The low relative dielectric permittivity ( ε r = 1.19 ± 0.01 at 300 GHz and ε r = 1.17 ± 0.01 at 2.0 THz) and corresponding loss tangent (tan δ= 0.011 ± 0.001 at 300 GHz and tan δ = 0.011 ± 0.001 at 2.0 THz) of the composite films are exploited in substrates for radio frequency filter structures designed for 300 GHz operation.īecause of the growing number of wireless communication devices and the increasing demand for faster data traffic, the currently used frequency bands are already or soon becoming congested. To be able to produce substrates with sufficient mechanical integrity, the nanoshells of SiO2 were reinforced with cellulose nanofibers resulting in a porous composite of very low mass density (0.19 ± 0.02 g cm −3), which is easy to press and mold to form films or slabs. The hollow nanospheres of amorphous SiO 2 with outstanding electromagnetic properties were obtained by a template-assisted Stöber process, in which a thin shell of silica is grown on polystyrene nanospheres first, and then the polymer core is burned off in a subsequent step. In this work, a porous composite of silica nanoshells and cellulose nanofibers is demonstrated as a suitable candidate of dielectric substrates to be used in future 6G frequency bands. The continuously increasing demand for faster data traffic of our telecommunication devices requires new and better materials and devices that operate at higher frequencies than today.

6g antenna