Ba4Al2Ti10O27 based glass ceramic as dielectric in high frequency applications

Abstract

Glass ceramics obtained via a true glassy phase are homogeneous and pore free, which makes them interesting for electronic applications, especially in the GHz frequency range. We discuss the glass-ceramic system with Ba4Al2Ti10O27 as the main crystalline phase and show material properties, including dielectric properties measured up to 110 GHz. Application examples are shown for filters and antennas in the GHz frequency range. The extremely high material homogeneity makes very precise manufacturing possible and enables MHz accuracy and reproducibility in GHz applications. The high linearity of the material properties is shown as well and makes high power applications, e.g., in cell phone base stations, possible. Also, applications in the MHz range are discussed.

Crystallization of LiNbO3 and NaNbO3 in niobiosilicate glass–ceramics

“…As such, glass–ceramics offer a unique processing route to explore anisotropic properties in an inherently isotropic glass matrix. They have been realized in a number of applications, including dental implants, 1 kitchenware, 2 transparent ballistic armor, 3 and high frequency dielectrics 2,4,5 …”

“…They have been realized in a number of applications, including dental implants, 1 kitchenware, 2 transparent ballistic armor, 3 and high frequency dielectrics. 2,4,5 More recently, there has been increasing interest in ferroelectric glass-ceramics for their anisotropic properties, including ferroelectricity, piezoelectricity, and second harmonic generation. 6 LiNbO 3 is a ferroelectric crystal of great interest due to its low dielectric and acoustic loss, high temperature stability (Curie temperature ∼1210 • C), and large pyroelectric and piezoelectric coefficients.…”