A Study on MgO-Ta₂O₅ System Ceramics for Microwave Component Application

Abstract

In this study, the microwave dielectric properties of the Mg₄Ta₂O₉ and Mg₅Ta₄O₁₅ ceramics with composition ratio and sintering temperature were investigated and the dielectric resonators with these ceramics were simulated. TiO₂ was doped in the Mg₄Ta₂O₉ ceramics for improvement of temperature property. The (1-x)Mg₄Ta₂O₉-xTiO₂ and Mg₅Ta₄O₁₅ ceramics were prepared by solid-state reaction method. According to the X-ray diffraction data, the (1-x)Mg₄Ta₂O₉-xTiO₂ ceramics had main phase of the Mg₄Ta₂O₉ and MgTi₂O₅ peaks were appeared by additions of TiO₂. In the Mg₅Ta₄O₁₅ ceramics, the Mg₄Ta₂O₉ and MgTa₂O₆ phase were coexisted and Mg₅Ta₄O₁₅ phase was appeared with increments of sintering temperature. Microwave dielectric properties of (1-x)Mg₄Ta₂O₉-xTiO₂ ceramics were affected by MgTi₂O₅ and TiO₂ phase. The quality factor had a little decrement compared to pure Mg₄Ta₂O₉, but there was excellent improvement in TCRF by addition of TiO₂. Densifications of the Mg₄Ta₂O₉ and MgTa₂O₆ and existence of the Mg₅Ta₄O₁₅ phase had influence on the microwave dielectric properties of the Mg₅Ta₄O₁₅ ceramics. Dielectric constant, quality factor and TCRF of the (1-x)Mg₄Ta₂O₉-xTiO₂ and Mg₅Ta₄O₁₅ ceramics sintered at 1450°C were 11.56-22.5, 24980-186410GHz, -36.02-+19.72ppm/°C and 8.2, 89473GHz, -10.91ppm/°C, respectively. ADS was used for simulation of DR. The simulated DR with the 0.5Mg₄Ta₂O₉-0.5TiO₂ and Mg₅Ta₄O₁₅ ceramics had the S₂₁ of -35.034dB at 11.97GHz and -28.493 dB at 10.50GHz, respectively.