Microwave Dielectric Properties of (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ Ceramic System

Abstract

In this study, the microwave dielectric properties of (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ ceramic system prepared by the conventional solid-state method have been investigated for application in mobile communication. It was found that the diffraction peaks of (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ ceramic system shift to higher angles as x increases from 0.4 to 0.7. It was also found that the X-ray diffraction patterns of the 0.4La(Mg_0.5Sn_0.5)O₃-0.6CaTiO₃ ceramics exhibited no significant phase difference at different sintering temperatures. The average grain size of the 0.4La(Mg_0.5Sn_0.5)O₃-0.6CaTiO₃ ceramics increases from 2.0 to 4.1 μm as the sintering temperature increased from 1250 to 1400°C. The dielectric constant increased from 27.7 to 49.4 and the quality factor (Q × f) decreased from 12,600 to 3,200 GHz for (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ ceramic system as the x value increases from 0.4 to 0.7 sintered at 1400°C for 4h. The average value of temperature coefficient of resonant frequency () increased from −65 to +46 ppm/°C as the x value increases from 0.4 to 0.7.

Keywords:

• Ceramics
• Sintering
• Dielectric response
• Scanning electron microscopy
• X-ray diffraction

Acknowledgment

This work was supported by the National Science Council of the Republic of China under Grant NSC 98-2622-E-262-003-CC3.

Communicated by Dr. George W. Taylor