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.