Microwave dielectric properties of Ca(Li1/4Nb3/4)O3–CaTiO3 ceramic systems

The microwave dielectric properties of Ca(Li1/4Nb3/4)O3–CaTiO3 ceramics have been investigated with regard to calcination temperature and the amount of CaTiO3 additive. Ca(Li1/4Nb3/4)O3 ceramics with an orthorhombic crystal structure can be synthesized by the conventional mixed oxide method by calcining at 750 °C and sintering at 1275 °C. The dielectric constant (ɛr), quality factor (Q × f0) and temperature coefficient of resonant frequency (τf) for Ca(Li1/4Nb3/4)O3 ceramics are 26, 13,000 GHz and −49 ± 2 ppm/°C, respectively. With increase in the CaTiO3 content, ɛr and τf are increased and the quality factor decreased due to the solid-solution formation between Ca(Li1/4Nb3/4)O3 and CaTiO3. The 0.7Ca(Li1/4Nb3/4)O3–0.3CaTiO3 ceramic exhibits ɛr of 44, quality factor (Q × f0) of 12,000 GHz and τf of −9 ± 1 ppm/°C.