Dielectric Characterization and Modeling of Composite Materials Based on Epoxy Resin/Black Iron Oxide/Titanates in Several Frequency Ranges

Abstract

The purpose of this article is to study the dielectric dispersion of two different ternary composites made of epoxy resin (RE), black iron oxide (Fe3O4) with one of the two titanates (calcium titanate (CaTiO3) or strontium (SrTiO3)) on several frequency bands. Additionally, the effect of the two titanates and the (Fe3O4) on the permittivity and conductivity of these ternary composites is investigated. These composite materials were characterized using time domain spectroscopy (TDS). The inclusion of the two titanates increased the real permittivity and conductivity of the two composites, shifting the resonance frequency (ƒR) towards the low frequency range and causing the opposite phenomenon for the static permittivity (ε s). The frequency dispersion behavior model for the complex permittivity has been proposed to improve the effectiveness of the predictive frequency model through a better choice of the damping factor and to bring theoretical and experimental findings closer together. Comparing these data shows that the proposed model is applicable to ternary combinations with high accuracy. The values of the quality factor (Q) obtained are encouraging in microwave applications. These composite materials witch containing CaTiO3 and SrTiO3 inclusions have contributed to the development of dielectric permittivity that suits very well frequency communication systems.

Dielectric Characterization of Heterogeneous Composites Using Time Domain Spectroscopy and Microwave Test Benches in Microwave Frequency

“…This increasing in the dielectric permittivity indicated the same effect of this perovskite titanate BaTiO 3 compared to what has been obtained in previous works [22][23][24][25][26][27][28][29][30]37,38 on other various binary, ternary and quaternary composites containing perovskite titanates such as calcium and strontium titanate.…”

“…This measurement technique, which has proven its credibility for decades, is based around a system composed of a step generator having an amplitude level of 200 mV and a rise time of 35 ps, with a built-in sampling head, associated with a mainframe digital oscilloscope. 26,27 The signal from the step generator propagates along a standard precision coaxial line of the APC-7mm type and with a characteristic impedance of 50Ω. This line connects to an APC-7mm/50Ω probe, in which the tubular sample is placed at its inlet.…”

Investigation on Dielectric, Electric, and Magnetic Properties of (Epoxy Resin-Titanate-Oxide/Ferrite) Ternary Composites at Microwave Frequency

“…Then, using a calculation program integrated into the PCM-TDR software (which does the DFT of the signals), harmonic processing of the reflection coefficient and resolution of the transcendence equations that allows getting the complex permittivity. 26,27 The various discontinuities in the coaxial line result in a multiple reflection with a complex reflection coefficient that is measured empirically from incident and reflected signals measurements by using the Fourier transform. 19,29 This experimental protocol, as it is illustrated in Fig.…”

“…The proportions achieved by weighing and transformed into a volume fraction to apply the effective mixture laws. 25,26 Table I lists the designation and composition of the samples.…”

“…The nonlinear regression method (generalized reduced gradient (GRG) Algorithm) fixes this factor to a second order polynomial by virtue of its nonlinear evolution with respect to the volume fractions of each constituent, ensuring a minimum difference between the experimental data and the theoretical values resulting from the effective dielectric permittivity and effective magnetic permeability of the material under investigation as well as an acceptable level of optimization. We attempted to advance the study of multiphase composites in this work by characterizing and investigating the dielectric and magnetic behaviours of these composite materials in one research, since the previous works 19,[21][22][23][24][25][26][27][28][29] only looked at the dielectric behavior. Additionally, the effect of additives (ST/BT, FE/FR) was added to similar multiphase mixtures in order to calculate their contribution and to compare the improvement in dielectric and electrical properties achieved by these additives with different other mixtures.…”