Microwave dielectric ceramics in the Sr1–𝑥Ba𝑥Ca4Nb4TiO17 (0 ≤ 𝑥 ≤ 0.75) composition series were fabricated via a solid-state mixed oxide route. All the compositions formed single phase in Sr1–𝑥Ba𝑥Ca4Nb4TiO17 (0 ≤ 𝑥 ≤ 0.75) solid solutions within the detection limit of in-house X-ray diffraction (XRD). The sintered microstructure of these ceramics comprised densely packed elongated and plate-like grains. The dielectric properties varied linearly with 𝑥. Relative permittivity (𝜀r) increased from 47.2 to 54.5, unloaded quality factor multiplying the resonant frequency (𝑄u 𝑓o) decreased from 11,984 to 9345 GHz and temperature coefficient of resonant frequency (𝜏f) increased from –78.6 to 20 ppm/°C with an increase in x from 0 to 0.75. In the present study, 𝜀r ≈ 51.6, 𝑄u 𝑓o ≈ 10,160 GHz (5.37 GHz) and 𝜏f ≈ –13.5 ppm/°C were achieved for Sr0.5Ba0.5Ca4Nb4TiO17 (𝑥 = 0.5) ceramics.
Volume 44, 2021
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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