Evaluation of dielectric properties of the barium titanium silicate (Ba2TiSi2O8) for microwave applications

This work presents the dielectric properties of Ba2TiSi2O8 in the Radiofrequency (RF) and Microwave (MW) regions. X-ray diffraction analysis showed that the material was obtained as a single-phase without the presence of spurious phases. Complex impedance spectroscopy demonstrated that there was no significant change of permittivity with temperature, whereas the dielectric loss was less than 1. Nyquist diagrams were modelled through an equivalent circuit using two associations of R-CPE related to the grain and the grain boundary effects. The MW analysis showed epsilon '(r) = 11.01 and tan delta = 4.55 x 10(-2), values that are close to the results obtained in the RF region. Moreover, the tau(f) value for Ba2TiSi2O8 was equal to - 47 ppm/degrees C which is close to the values adequate for a microwave device application. The numerical simulation demonstrated the operation of the material as a Dielectric Resonator Antenna (DRA), where a reflection coefficient below - 10 dB, a realised gain of 6.739 dBi, a bandwidth of 452.96 MHz and a radiation efficiency around 100% were observed. The results indicate that Ba2TiSi2O8 would be an interesting candidate in microwave operating devices in the C-band, as well as in devices operating in RF.