Microwave dielectric properties and low-temperature cofiring of BaTe ₄O ₉ with aluminum metal electrode

Polycrystalline BaTe4O9 ceramic compound was investigated as a promising microwave dielectric compound for low-temperature cofired ceramics (LTCC) applications. The binary phase BaTe4O9 was synthesized and subsequently densified over the temperature range of only 500°-550°C, which allows for low-temperature cofiring with aluminum metal. The dielectric properties of BaTe4O9 ceramics sintered at 550°C for 2 h were determined in the microwave region of 12-14 GHz. The dielectric constant and Q×f product obtained were 17.5 and 54 700 GHz at 12 GHz, respectively. The temperature coefficient of resonance frequency showed a negative value of -90 ppm°C. In terms of its evaluation for LTCC, the BaTe4O9 composition was found to be chemically compatible and successfully cofired with highly conductive aluminum electrode, while maintaining good electrical performance.