Experimental Investigation of Calcium-Doped Zinc Aluminate Nanoparticles as a Promising Material for Microwave Applications.

Abstract

Miniaturization of microstrip patch antennas (MPAs) is vital in applications such as wireless networks, mobile devices, global positioning satellites, and upcoming wireless terminals. This miniaturization has led to a demand for new materials with higher permittivity compared to the existing ones. Zinc aluminate (ZnAl2O4) ceramic is an exceptional and versatile material in this context, thanks to its high dielectric permittivity and low tangent loss, making it suitable for microwave applications. This article explores the feasibility of sol-gel-prepared Ca-doped ZnAl2O4 ceramic nanoparticles to be useful in fabricating a MPA. These nanoparticles were examined using X-ray diffraction, which confirmed their polycrystalline structure, and the morphological investigation evidenced the spherical grains having a mean diameter of 16 nm. The dielectric permittivity of the ZnAl2O4Ca nanoparticles is 21.11, with a tangential loss of 0.0247. A prototype MPA made by using Ca-doped ZnAl2O4 nanoparticles showed a return loss of -20.92 dB at a resonance frequency of 6.8 GHz with a bandwidth of 600 MHz. These results indicate that Ca-doped ZnAl2O4 ceramic nanoparticles possess exceptional dielectric characteristics, which make them a promising candidate for MPA applications.