The Influence of Production Conditions of ВаO – Sm₂ – O₃ – 4TiO₄ Ceramic Materials on the Formation of Microwave Properties

A frequency-dependent ceramic material with high temperature stability of the resonant frequency has been obtained, which guarantees stable operation of devices based on it when temperatures change. The article presents the results of the influence of the production conditions on the microstructure and dielectric properties, as well as on the microwave parameters of ceramics. The solid-phase synthesis method was used to obtain the material. The synthesis was carried out at a temperature of 1000 °C for 2 h with subsequent thermal firing. It is shown that the optimal microwave properties of BaSm2Ti4O12 ceramics are obtained at sintering temperatures in the range of 1360–1380 °C. It is established that by changing the sintering temperature, the dielectric permeability of the ceramic material can be increased almost twice. The resonant frequencies of ceramics for various sintering temperature regimes were determined experimentally. The resonant frequencies of the materials range from 6.7 to 8.9 GHz. It is found that the quality factor of the ceramic material near the resonant frequencies significantly depends on the operating temperatures. At operating temperatures above 40 °C, a decrease in the quality factor of the ceramic material by 22–30 % is observed. By studying the frequency dependencies of the real and imaginary parts of the dielectric permittivity of the ceramics under study, possible polarization mechanisms were established. It is shown that the resonant nature of the dielectric permittivity dispersion is characteristic of the 100–900 MHz frequency range. At gigahertz frequencies, dipole and migration polarization prevail. Due to their properties in the gigahertz frequency range, the ceramics obtained can be used for the manufacture of substrates for microstrip antennas and microwave circuits, as well as for dielectric resonator antennas and components of satellite and mobile communication systems.

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