Synthesis and investigation of dielectric ceramic nanoparticles for microstrip patch antenna applications

Zinc aluminate (ZnAl₂O₄) is a well-recognized ceramic demanded in several microwave applications. Further, the addition of dielectric materials in ZnAl₂O₄ improved its dielectric properties, which is promising for the realization of a microstrip patch antenna. This article reports the investigation of ZnAl₂O₄TiO₂ (ZAT) dielectric ceramic nanoparticles synthesized by the sol-gel process. The X-ray diffraction analysis revealed the crystalline nature of the prepared nanoparticles, with a tetragonal structure of anatase-, and rutile-TiO₂ phases coexisting with the cubic phase of ZnAl₂O₄. The estimated crystallite size of the dielectric ceramic is 13.3 nm. Transmission electron microscopy (TEM) micrographs demonstrated the spherical grains with their mean diameter of 14.75 nm, whereas the selected-area electron diffraction (SAED) pattern endorsed the crystallinity of the sample. Raman measurement revealed the vibrational modes in accordance with the TiO₂ and ZnAl₂O₄ compounds. The dielectric properties of the ZAT sample showed the dielectric permittivity in the range of 22.12-21.63, with its minimum loss from 0.056 to 0.041. Finally, a prototype microstrip antenna was fabricated using the prepared nanoparticles, which demonstrated a return loss of - 30.72 dB at the resonant frequency of 4.85 GHz with its bandwidth of 830 MHz.