Broadband Characterization of Silicate Materials for Potential 5G/6G Applications

This paper provides a broadband dielectric characterization of different silicate substrates up to 115 GHz, to fill the gap of the properties of different kinds of glasses in a broad part of the mm-wave spectrum. Both the internal structure (crystalline or amorphous) and the chemistry of the substrates has an influence in the permittivity and loss tangent of the material. Quartz and sapphire are crystalline materials that exhibit low loss in the mm-wave frequency range. Amorphous silicates generally have higher loss values than crystalline materials, and within the glasses, the level of impurities added also affects the dielectric loss. Several characterization techniques have been employed to cover a broad frequency band. The limitations of the different characterization techniques are also included. Once the dielectric properties of substrates are characterized, a metasurface has been designed and fabricated at 100 GHz to increase the reflection in window glass and provide coverage on areas that would otherwise be shadowed. The measurement results are in good agreement with the simulations.