Dielectric characterization of Mg–Zn ferrite-based high permittivity flexible substrate for SNG metamaterial

Abstract

This article reports the preparation of MgxZn(1-x)Fe2O4 ferrite-based flexible substrate using the sol–gel synthesis method. A stove-shaped metamaterial unit cell is designed and fabricated on a flexible substrate, and the microwave performance of the structure is investigated. The developed flexible composite substrate is built using PVA glue and a micro-scale of Mg–Zn ferrite nanoparticle powder, while this powder is used as filler. The structural (XRD) and morphological (FESEM) investigation allows for being used as a flexible substrate. The dielectric and loss tangent properties of the substrate are manipulated using different weight ratios of filler, while PVA keeps the flexibility features. The substrate achieved a dielectric constant (Td), and loss tangent (T) of 6.101 and 0.00899 are measured using DAK 3.5 Kit while the bending performance is investigated for 0°, 30°, 60°, and 90°, respectively. The suggested structure exhibited SNG properties within the frequency range of 4.77–5.65 GHz, 8.75–10.60 GHz, and 16.86–17.66 GHz, respectively, and near-zero index is exhibited within the frequency range of 5.216–6.388 GHz, 9.626–12.617 GHz, and 17.277–18.276 GHz, respectively. The measured response of S21 achieved a bandwidth of 4.88–5.76 GHz, 8.26–10.69 GHz, and 15.87–17.93 GHz with a maximum magnitude of −40.57 dB, −39.41 dB, and −27.63 dB at 5.31 GHz, 9.77 GHz, and 17.123 GHz resonance frequency. The proposed flexible substrate-based MTM structure can be a potential candidate for wireless communications in the S-, C-, and Ku-bands, especially as the SNG material that can increase the antenna bandwidth and gain enhancement.