Research & Developments for Millimeter-Wave Dielectric Forsterite with Low Dielectric Constant, High $Q$, and Zero Temperature Coefficient of Resonant Frequency

• Published in: Japanese Journal of Applied Physics 2013-09, Vol.52 (9), p.09KH02-09KH02-4
• Main Authors: Tsunooka, Tsutomu, Ando, Minato, Suzuki, Sadahiko, Yasufuku, Yoshitoyo, Ohsato, Hitoshi
• Format: Article
• Language: English
• Subjects: Adjustment; Ceramics; Dielectric constant; Forsterite; Raw materials; Resonant frequencies; Rutile; Tuning; Zero temperature coefficient
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.52.09KH02

Forsterite Mg 2 SiO 4 is a candidate for millimeter-wave dielectrics because of its high $Q$ and low dielectric constant $\varepsilon_{\text{r}}$. Commercial forsterite has been improved with a high $Q$ of 240,000 GHz using high-purity and fine raw materials, and the temperature coefficient of resonant frequency ($\mathit{TCf}$) can also be adjusted to near-zero ppm/°C by adding 24 wt % rutile compared with that in a previous study. In this study, the $\mathit{TCf}$, $\mathit{TC}\varepsilon$, and $\varepsilon_{\text{r}}$ of forsterite ceramics with rutile added are studied for the tuning conditions. Zero ppm/°C $\mathit{TCf}$ of the forsterite with 30 and 25 wt % rutile added was achieved at 1200 °C for 2.5 and 2.25 h, respectively. The $\varepsilon_{\text{r}}$ values of the near-zero $\mathit{TCf}$ forsterite with 30 and 25 wt % rutile added are 11.3 and 10.2, respectively.