Synthesis and characterization of metal-ferrite nanoparticles based flexible substrate for microwave sensing

Abstract

Synthesis and characterization of nanoparticles have become the spotlight of research in the material science field due to their tuneable, efficient, and sustainable properties for sensing technologies. Metal-ferrite compositions show potential for different microwave applications due to their unique structural and magnetic properties. State- of-the-art research on conventional microwave substrates shows inherent limitations of limited flexibility, limited adaptability to irregular surfaces, and decreased efficacy in complex sensing environments. These limitations motivate the development of flexible substrates that promise improved flexibility, conformability to non-standard surfaces, and performance in multifaceted sensing environments. This research aims to bridge the gap between the inherent characteristics of metal-ferrite-based nanoparticles and their practical performance, focusing on creating flexible metamaterials for microwave chemical sensing. This research focuses on synthesizing and characterizing two metal- ferrite nanoparticles-based flexible substrates for microwave sensing applications.

Firstly, CoxCa(0.90-x)Ni0.10Fe2O4 based flexible microwave substrate is developed, which achieved dielectric constant of 1.77 to 3.32 with loss tangents ranging from 0.031170 to 0.1929 for x=25% to x=75%. After that, a rectangular enclosed cross-dumbbell metamaterial structure is designed for industrial chemical contamination sensing. Secondly, Zn0.5-xCa0.1Co0.4+xFe2O4-based flexible substrate is developed for food chemical sensing applications, where the dielectric constant value can be varied with composition values. The nanoparticles of the compositions undergo thorough characterization utilizing various techniques, including Field Emission Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-ray Diffraction, Magnetic Force Microscopy, Conductive Atomic Force Microscopy, and Vibrating Sample Magnetometry. The developed flexible substrates are utilized for metamaterial-based microwave sensors. The first design is employed for sensing different concentrations of industrial chemicals like methanol and ethanol, and food chemicals sensing like formalin, saccharin, and sucralose industrial benzoate are evaluated using the second metamaterial structure. Both structures show sequential frequency shifting with different contamination levels, which ensures effective sensing capabilities. Therefore, the developed flexible substrate has excellent potential for high-performance microwave sensing applications.