Improved high Q value of (1 − x)Ca(Mg1/3Ta2/3)O3–xCa0.8Sm0.4/3TiO3 solid solution with zero temperature coefficient of resonant frequency

High-relative-permittivity and low-loss ceramics in the (1 − x)Ca(Mg1/3Ta2/3)O3–xCa0.8Sm0.4/3TiO3 system have been prepared by the conventional solid state route and their microwave dielectric properties have been investigated. (1 − x)Ca(Mg1/3Ta2/3)O3–xCa0.8Sm0.4/3TiO3 solid solution exhibited orthorhombic crystal structures for all compositions. A rapid grain growth is observed at temperatures higher than 1450 °C, which would lead to a decrease in the density and the Q × f of the ceramics. A near-zero temperature coefficient of resonant frequency can be achieved for Ca(Mg1/3Ta2/3)O3 with the addition of Ca0.8Sm0.4/3TiO3. The temperature coefficient of resonant frequency increases with increasing Ca0.8Sm0.4/3TiO3 content and tunes through zero at x = 0.45. Specimen using 0.55Ca(Mg1/3Ta2/3)O3–0.45Ca0.8Sm0.4/3TiO3 possesses an excellent combination of microwave dielectric properties: ɛr ∼ 44.96, Q × f ∼ 41,700 GHz (where f = 6.6 GHz, is the resonant frequency) and τf value of 0 ppm/°C. It is proposed as a suitable candidate material for today's 3G passive components and small-sized GPS patch antennas.