Microwave Dielectric Properties of V₂O₅–Doped (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ Ceramic System

Abstract

The microwave dielectric properties of V₂O₅–doped (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ ceramic system prepared by the conventional solid-state method were investigated with a view to their potential for mobile communication. The X-ray diffraction peaks of (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ shifted to higher angles as x increased from 0.4 to 0.7. The X-ray diffraction patterns of the 0.4La(Mg_0.5Sn_0.5)O_3–0.6CaTiO₃ revealed no significant variation of phase with sintering temperatures. The average grain size of the 0.4La(Mg_0.5Sn_0.5)O_3–0.6CaTiO₃ increased from 3.1 to 8.6 μm as the sintering temperature increased from 1400 to 1550°C. The dielectric constant increased from 28.5 to 48.7 and the quality factor (Q × f) decreased from 46,800 to 22,900 GHz for (1-x)La(Mg_0.5Sn_0.5)O₃-xCaTiO₃ as x increased from 0.4 to 0.7 that were sintered at 1550°C for 4h. The average value of temperature coefficient of resonant frequency (τ_f ) increased from −56 to +46 ppm/°C as x increased 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.