Preparation and microwave dielectric properties of Li3(Mg0.92Zn0.08)2NbO6–Ba3(VO4)2 composite ceramics for LTCC applications

• Microwave properties of ϵr ∼ 16.3, Q × f ∼ 50,084 GHz and τf ∼ 1.5 ppm/°C are achieved.
• The τf value of the LMZN ceramic can be adjusted to near zero by adding BV.
• The LMZN–BV composite ceramic can be well sintered at a relatively low temperature.
• The composite ceramic has a good chemical compatibility with Ag electrode.

In this work, the (1 − x)Li3(Mg0.92Zn0.08)2NbO6–xBa3(VO4)2 (x = 0.1–0.35) ceramics were prepared via a conventional solid state reaction route. The phase composition, microstructure and microwave dielectric properties were investigated by an X-ray diffractometer (XRD), a scanning electron microscope and a network analyzer. The XRD results indicated that the Li3(Mg0.92Zn0.08)2NbO6 and Ba3(VO4)2 phases could well coexist without forming any secondary phases. The dielectric constant (ϵr) and quality factor (Q × f) values of the Li3(Mg0.92Zn0.08)2NbO6 ceramic decreased with the addition of Ba3(VO4)2 phase, however its temperature coefficient of resonant frequency (τf) value was improved significantly. Excellent microwave dielectric properties of ϵr ∼ 16.3, Q × f ∼ 50,084 GHz (at 8.64 GHz) and τf ∼ 1.5 ppm/°C were achieved for the x = 0.3 sample when sintered at 950 °C for 4 h. The chemical compatibility with Ag electrode indicated that the 0.7Li3(Mg0.92Zn0.08)2NbO6–0.3Ba3(VO4)2 composite ceramic would be a promising material for the low temperature cofired ceramic applications.

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