Use of Titanates to Achieve a Temperature‐Stable Low‐Temperature Cofired Ceramic Dielectric for Wireless Applications

Abstract

A low‐loss and near‐zero temperature coefficient of resonant frequency ( T f ) low‐temperature cofired ceramic (LTCC) host dielectric was developed for portable consumer wireless device applications. The low T f was realized by compensating the Al 2 O 3 ‐filled‐glass dielectric with admixtures of TiO 2 (negative temperature coefficient of dielectric constant ( T ɛ )) in the starting formulation. XRD data indicated a portion of the TiO 2 in the starting formulation dissolved into the glass, and extensive formation of crystalline titanium compounds was observed via a nucleation and growth mechanism. The dissolution of TiO 2 in the glass and subsequent formation of titanium compounds was believed to result in the relatively small amount of TiO 2 required to achieve a near‐zero T f in the final sintered structure.