Dielectric property and polarization mechanism of sodium silicate glass in GHz–THz range

Abstract

Glass is a candidate of dielectric materials for high-frequency communication technologies, and it is important to clarify the dielectric function of glass in GHz–THz range. In this study, the complex permittivities of silica glass and sodium silicate glasses were measured at 0.5–15 THz using terahertz time-domain spectroscopy and terahertz spectroscopic ellipsometer systems. The dielectric permittivity and loss of silica glass were extremely low in the GHz band, whereas those of sodium silicate glasses were relatively high in the GHz band. The dielectric dispersion at frequencies lower than 9 THz became larger with increasing Na content, and the dispersion greatly affected the dielectric permittivity and loss in the GHz band. Molecular dynamics simulations indicated that vibrations and migrations of Na ions occur in the frequency range of GHz to THz, and the dielectric dispersion at frequencies below 9 THz is due to the vibrations and migrations of Na ions, which are easily moved by an electric field. These results suggested that glass materials with a low amount of alkali metal ions are required when glass materials are applied as a high-frequency dielectric material.

Analysis of the Dielectric Properties of Alkali-Free Aluminoborosilicate Glasses by Considering the Contributions of Electronic and Ionic Polarizabilities in the GHz Frequency Range

“…The low dielectric property shortens propagation delay and mitigates signal loss and also leverages larger device geometries that decrease sensitivity to fabrication tolerances. Investigations on the dielectric property are essential for understanding the glass structure as it relates to the polarizability of constituent ions forming the glass [ 9 , 10 , 11 , 12 , 13 ]. Moreover, they can provide insight into the chemical structure of the glass at GHz frequencies, where the electronic and ionic mechanisms contribute to the polarizability.…”

“…In this connection, the characterization of the dielectric properties of glass materials in the GHz frequency range has gained growing interest in designing new glass compositions for use in printed circuit boards (PCBs) as a reinforcing material for high-speed data transmission applications. Since the dielectric constant (ε) is calculated based on the polarizability and density of glasses through the Clausius–Mossotti (CM) equation [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ], the investigation of polarizability characteristics such as dielectric polarizability (α D ), oxide ion polarizability (α O2− ), and optical basicity (Λ) is important for understanding the dielectric responses of glasses in the GHz frequency region. The dielectric properties of glasses are also influenced by the low-frequency (GHz–THz) and the high-frequency (optical) modes [ 9 , 10 , 11 , 12 , 14 , 15 , 16 ].…”

“…Since the dielectric constant (ε) is calculated based on the polarizability and density of glasses through the Clausius–Mossotti (CM) equation [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ], the investigation of polarizability characteristics such as dielectric polarizability (α D ), oxide ion polarizability (α O2− ), and optical basicity (Λ) is important for understanding the dielectric responses of glasses in the GHz frequency region. The dielectric properties of glasses are also influenced by the low-frequency (GHz–THz) and the high-frequency (optical) modes [ 9 , 10 , 11 , 12 , 14 , 15 , 16 ]. The dielectric constant at a GHz frequency is a result of contributions from the electronic and ionic polarizabilities, whereas the dielectric constant at an optical frequency is a result of contribution from the electronic polarizability [ 7 , 14 , 15 , 16 ].…”

Dielectric response and polarization mechanism of alkali silicate glasses in gigahertz to terahertz frequency range

“…Furthermore, we measured the dielectric responses up to the terahertz range to evaluate the dielectric properties at different gigahertz bands and to understand how the gigahertz dielectric properties of the glasses were affected by the dielectric responses in the terahertz range. 17 The complex permittivity in the gigahertz range is often measured using an electrical resonance technique that is applicable below 300 GHz. 18 By contrast, the complex permittivity in the terahertz range is usually estimated via infrared reflectance and transmittance 19 ; however, glasses are often opaque in the terahertz range, which prevents the transmittance from being accurately determined.…”

“…To identify the effects of alkali‐metal ions on the dielectric properties, we examined five types of alkali‐silicate glass: 70SiO 2 ‐30Li 2 O, 70SiO 2 ‐30Na 2 O, 70SiO 2 ‐30K 2 O, 70SiO 2 ‐30Rb 2 O, and 70SiO 2 ‐30Cs 2 O. Furthermore, we measured the dielectric responses up to the terahertz range to evaluate the dielectric properties at different gigahertz bands and to understand how the gigahertz dielectric properties of the glasses were affected by the dielectric responses in the terahertz range 17 …”