RF and Microwave Electrical Properties Study 
of the Magneto-Dielectric Resonator Antenna of the Matrix Composite [SrFe12O19 (SFO)1−x-BiFeO3(BFO)x]
AbstractsIn this work, we prepared ceramic composites based on SrFe12O19 (SFO)-BiFeO3 (BFO) strontium hexaferrite. The SFO and BFO were synthesized by the solid-state reaction method, and we used both x-ray diffraction and infrared spectroscopy for structural characterization of the composite matrix. The electrical and dielectric properties were measured in the radiofrequency range by using Impedance Spectroscopy, and the Nyquist plots were fitted by equivalent circuits. For the microwave range, we used the Hakki–Coleman method, and we also studied the thermal stability of the composite. The resonator cylinders were fabricated using a mixture of SFO and BFO, with BFO concentrations of 20 wt.%, 40 wt.% and 60 wt.%, named SB20, SB40 and SB60, respectively. The insertion of BFO improved the thermal stability of the material and the composite permittivity. These composites were tested as dielectric resonator antenna, which presented reflection coefficients below − 10 dB, gain above 4.9 dBi and efficiency above 67%.