Structural, dielectric, and magnetic properties characterization of sol–gel synthesized CaxZn(0.90-x)Ni0.10Fe2O4 nanopowder and its application as flexible microwave substrate with polarization-insensitive SNG metamaterial

Abstract

In this work, CaxZn(0.90-x)Ni0.10Fe2O4 nanopowder-based new flexible microwave substrates are prepared using the sol–gel method for metamaterial applications. Three different x values are chosen as x = 25, 50, 75 and termed as Ca25, Ca50, and Ca75 respectively. The structural and morphology of synthesized materials are investigated with XRD and FESEM analysis. The dielectric properties were also determined and the obtained values for dielectric constant (εr) and loss tangents (Tδ) are ranges from 3.25 to 4.25 for εr and 0.0025 to 0.0065 for Tδ for Ca25, Ca50, and Ca75 respectively. In addition, the magnetic permeability μr and magnetic loss tangent (Tδm) values are estimated from the scattering parameters S11 and S21 obtained by using Agilent module 85071E, and the achieved values of μr and Tδm are ranges from 0.875 to 1.00 and 0.0035 to 0.0075 respectively. Later, the proposed metamaterial unit cell consists of a square split ring resonator (SSRR) and a circular SRR (CSRR) loaded with a plus shape is designed and fabricated on the proposed flexible substrates obtained from the synthesized CaxZn(0.90-x)Ni0.10Fe2O4 nanopowders to validate their application as metamaterials. The novelty of the proposed work is found in the unit cell being polarization-insensitive and having a multiband, low electrical dimension that improves the EMR, single-negative characteristics with high flexibility and lightweight and suitable for C, X, and Ku bands of microwave regime.