Electromagnetic Characterization of a Composite (RE-CB-MT) by Time Domain Spectroscopy

The aim of this article is to study the dielectric behavior (ε, σ) in microwaves domain of composites made with Epoxy Resin (RE), Carbon Black (CB), and Magnesium Titanate (MT) on a large band of frequency. This kind of composites is very solicited for applications and miniaturization of the components circuits (cavities, antennas, substrates, etc.) in hyperfrequency electronics. In this study we have also highlighted the effect of the fillers nature and their concentrations on the behavior of these composites. The results obtained by time domain spectroscopy (TDS) have revealed the strong dependence of complex permittivity of the composite materials on both the nature and the concentration of conductive environment. Low frequency analysis (500 MHz) has been investigated to determine the conductivity of composites which is related to the percolation phenomenon. Moreover, the comparison between experimental results and theoretical models shows that the modeling Lichtenecker law is applicable to the ternary mixture in this frequency range and is in accordance with the approach postulated by Bottreau

Dielectric behavior of a quaternary composite (RE, BT, MnO

The main objective of this paper is to study the dielectric behavior of a quaternary composite, made from a mixture of barium titanate (BT), manganese dioxide (MnO2) and calcium oxide (CaO) in the same epoxy resin matrix (RE) maintained at 70% by volume fraction, while those of the other constituents are variable and completing each other in a way to achieve the remaining proportion, i.e. 30%. Random mixtures are made at room temperature and under atmospheric pressure. A dielectric characterization of this mixture type was performed by time-domain spectroscopy (TDS) over a frequency wide band (DC–2 GHz). This has been carried out to illustrate the effect of two oxides (MnO2 and CaO) simultaneously at low frequency (500 MHz), in the presence of (BT), on the composite dielectric behavior. This has led consequently to make a comparison between the present acquired results and those of the ternary composite, where (MnO2) and (CaO) act separately. The results obtained so far in this study allowed us to check the validity of the modified Lichtenecker law (MLL)-based predictive model in the quaternary composite case. The interest of this study lies on applications of these materials in microelectronics circuits and absorber materials in telecommunication domain

Dielectric behavior of ternary mixtures: epoxy resin plus titanates (MgTiO

In the present work, we study the dielectric behavior of various ternary mixtures composed of epoxy resin (RE), of one of three different titanates (barium titanate, BaTiO3; calcium titanate, CaTiO3; magnesium titanate, MgTiO3) respectively with one of three oxides (calcium oxide, CaO; manganese dioxide, MnO2; zinc oxide, ZnO) using time domain reflectometry (TDR). The different composites are mixed at room temperature in different volume fractions keeping the epoxy resin at a constant volume fraction. Several mixture combinations are studied to see the oxides influence on the titanates dielectric behavior in the range from DC to 10 GHz. This is done through the experimental determination of the dielectric constant εs. A noticeable effect has been recorded at the low frequency and which consists of an increase of this dielectric permittivity when growing the volume fraction of manganese dioxide. One meaningful point of this study is the lowest static conductivity value (8.017 × 10−3/(Ωm)) being reached with an incursion of 7.5% of MnO2 in a ternary mixture composed of RE, MgTiO3 and MnO2. In addition, the behavior obtained experimentally has been validated by the Lichtenecker modified model. This study interest lies on an application of these materials in microelectronics and particularly in telecommunication components manufacturing

Dielectric behavior of a sintered heterogeneous ternary composite resin/BT/Cu

In this paper, we investigate and model the dielectric behavior of a ternary composite prepared at room temperature with a mixture of epoxy resin (RE), barium titanate (BT) and copper oxide (Cu2O), sintered at three different temperatures (150 °C, 200 °C, and 250 °C). Time domain spectroscopy (TDS) is used to characterize samples in the range [DC to 2 GHz] by performing a particular study at low frequency (500 MHz). The latter focused on both the sintering and the Cu2O addition effects on a ternary composite dielectric behavior. These effects were quantified as a function of the BT volume fraction. For this purpose, we used an optimization method based on nonlinear regressions to determine the permittivity, to minimize systematic errors of this dielectric parameter, and to show the effect of Cu2O on it. Moreover, we attempt to explain the sintering temperature effect on this kind of mixtures through the modified Lichtenecker model. As a matter of fact, the importance of this law is allocated on one hand to the validation and concordance of the experimental results with those of the theory and on the other hand to the temperature effect investigation on the form factor given by the modified Lichtenecker law

Study of dielectric behavior of ternary mixtures of epoxy/titanates (MgTiO

The aim of this paper is to study and to model the dielectric behavior of various ternary composites prepared with epoxy resin (RE), one type of titanates (magnesium titanate MgTiO3, calcium titanate CaTiO3, strontium titanate SrTiO3, and barium titanate BaTiO3) with carbon black (CB). The study has therefore been focused on the effect of adding carbon black to titanate included in an epoxy matrix. The effects have been quantified according to the volume fraction of carbon black. In this work, we present a method based on nonlinear optimization for determining the permittivity of the every constituent, in order to minimize systematic errors and mount the effect of carbon black. The time domain reflectometry (TDR) approach is used to characterize the samples under test in the range from DC to 10 GHz. The conductivity behavior study is performed at a low frequency of 400 MHz, throughout this work. We explain the carbon black effect on the ternary mixtures by using the substitution principle for predicting their dielectric behavior. The experimental results confirm the concordance with the modified Lichtenecker mixture law. To predict the electromagnetic behavior of the ternary composites in quantitative manner, we use a numerical optimization method for identification the parameters of the theoretical model. Finally, these materials find their interest in the miniaturization of electronic components used in microelectronic and telecommunication applications