Magnetron sputtering of Al on hollow glass microspheres and its effects on the dielectric properties of artificial dielectric materials

The hollow glass microspheres were coated with Al by DC magnetron sputtering. XRD and SEM were used to investigate the structure and morphology of the microspheres coated with Al，respectively. The hollow glass microspheres coated and uncoated with Al，as well as the polymer binder were used to prepare the artificial dielectric materials，and the dielectric properties at 8.2~12.4 GHz were measured with a network vector analyzer. The results show that the hollow glass microspheres could be coated with Al film by a magnetron sputtering，and the Al films are combined well with the microsphere substrates. At the same addition amount of the microspheres coated with Al，the dielectric constant of the artificial dielectric materials increases with the thickness of Al film. Meanwhile，keeping the thickness of Al film constant，the dielectric constant of the artificial dielectric materials increases with the addition amount of microspheres coated with Al. The artificial dielectric material has a low dielectric loss of less 3 than 0.02 and a low density of no greater than 0.8g/cm.