Dielectric characterisation and numerical investigation of SrBi2Nb2O9–Bi2O3 composites for applications in microwave range

Abstract

We present a study of the dielectric properties and behaviour of dielectric resonator antennas (DRAs) based on SrBi2Nb2O9 (SBN)-Bi2O3 composites. X-ray diffraction is used for structural characterisation of the samples and it indicates the formation of a new phase after the addition of Bi2O3. The temperature coefficient of resonant frequency (τ f) is measured and the results demonstrate that the increment of Bi2O3 improves the thermal stability of the composites from −345.62 to −235.02 ppm/°C. For the dielectric properties, it is observed that Bi2O3 additions cause the formation of new phases, which present higher dielectric ϵ’ than SBN. Our numerical simulations show that the materials operate as DRAs and that SBN-Bi2O3 composites could be potential candidates for DRAs operating in the S band.