scholarly journals Variation of Dielectric Constant of Indian Soils with Their Physical Parameters at C-Band Microwave Frequency

2014 ◽  
Vol 03 (08) ◽  
pp. 15396-15400 ◽  
Author(s):  
P. R. Chaudhari
Keyword(s):  
Dielectric Constant ◽  
Microwave Frequency ◽  
Physical Parameters ◽  
Indian Soils

scholarly journals The Effects of SLS on Structural and Complex Permittivity of SLS-HDPE Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Abubakar Dantani Meli ◽  
Zulkifly Abbas ◽  
Mohd Hafiz Mohd Zaid ◽  
Nor Azowa Ibrahim
Keyword(s):  
Dielectric Constant ◽  
Complex Permittivity ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Soda Lime ◽  
Physical Structure ◽  
Host Matrix ◽  
Lower Dielectric Constant ◽  
Absorbing Material ◽  
Diffraction Patterns

RS-4050 is a rigid epoxy based magnetic castable microwave absorbing material; it has been used in many areas of waveguide application as a microwave waveguide terminations and dummy loads. In recent years, there is a demand for composites material with lower dielectric constant higher loss factor for microwave application. This research, the effect of soda lime silica (SLS) on structural and complex permittivity of soda lime silica-high density polyethylene (SLS-HDPE) composites was conducted in order to explore the possibility of substituting RS-4050 with SLS-HDPE composites as a microwave waveguide terminations and dummy loads. Elemental weight composition of the SLS glass powder and HDPE was identified through scaling of different percentage of SLS and HDPE. X-ray diffraction (XRD) was used to investigate the crystallinity behavior of SLS-HDPE composites. The proposed SLS-HDPE composites material was studied at frequencies 8 to 12 GHz. The study was conducted using waveguide Agilent N5230A PNA technique. The effect of microwave frequency on complex permittivity properties for SLS-HDPE composites of different percentages of SLS and HDPE (10% SLS-90% HDPE, 20% SLS-80% HDPE, 30% SLS-70% HDPE, 40% SLS-60% HDPE, and 50% SLS-50% HDPE) were investigated. Results showed the diffraction patterns reveal good amorphous quality with a genuinely properties structure. The microwave frequency and composites percentages significantly influenced the complex permittivity (real and imaginary) properties of the composites. Moreover, the complex permittivity increased as the percentage of SLS filler increased in the host matrix HDPE as a result of increased in composite density due to less volume being occupied by the filler as the percentage increased. The complex permittivity of the smallest and largest percentages of SLS (10% and 50%) was (2.67-j0.05) and (3.45-j0.35), respectively. The study revealed that the best sample for waveguide application as microwave terminator is 50% SLS as it has the highest dielectric constant, highest loss factor, and highest loss tangent as compared to 10% SLS to 40% SLS. Also 50% SLS has the highest absorption properties as compare to 10% SLS, 20% SLS, 30% SLS, or 40% SLS. The XRD physical structure of the SLS-HDPE composites revealed the absorption characteristics of different percentages of the materials. The SLS-HDPE composites can be applied in the area of waveguide as a microwave waveguide terminations and dummy loads.

Dielectric Relaxation Studies of Ternary Mixture of Dimethyl Phthalate and Heptanol in Benzene Solution in the Microwave Region

2015 ◽  
Vol 70 (7) ◽  
pp. 507-512
Author(s):  
A. Mushtaq Ahmed Khan ◽  
M. Subramanian
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Benzene Solution ◽  
Microwave Frequency ◽  
Viscous Force ◽  
Dimethyl Phthalate ◽  
Flow Process ◽  
Relaxation Studies

AbstractThe molecular structure and molecular forces in liquids and solutions, in particular, have been investigated by dielectric relaxation studies. The nature and strength of the molecular interactions have been established as the main cause for the chemical behaviour of compounds. The dielectric behaviour of dimethyl phthalate with heptanol in benzene solution has been studied at a microwave frequency of 9.36 GHz at different temperatures 303, 308, and 313 K. Different dielectric quantities such as dielectric constant (ε′), dielectric loss (ε″), static dielectric constant (ε0), and dielectric constant at optical frequency (ε∞) have been determined. The relaxation time τ has been calculated by both Higasi’s method and Cole–Cole method. The dielectric relaxation process can be treated as a rate process just like the viscous flow process. The complex system investigated shows the maximum relaxation time values at high temperatures by both Higasi’s method and Cole–Cole method. The molar free energies of activation of dipole moment (ΔFτ) and viscous force (ΔFη) have also been reported. The excess dipole moment is also determined. The excess dipole moment is a qualitative index for the presence of a hydrogen bond in the ternary system. The value of Δμ obtained in our study indicates the presence of hydrogen bonds between the components of the mixture. The system investigated shows that the relaxation time value increases with the increase in the concentration of solute.

HIGH DIELECTRIC CONSTANT AND NONLINEAR ELECTRIC RESPONSE IN Bi2Sr2SmCu2Oy

1996 ◽  
Vol 10 (27) ◽  
pp. 1365-1377 ◽  
Author(s):  
M. CHANDRA SEKHAR ◽  
B. GOPALA KRISHNA ◽  
M. MAHESH KUMAR ◽  
S.V. SURYANARAYANA
Keyword(s):  
Dielectric Constant ◽  
Temperature Region ◽  
Localization Length ◽  
Solid State Reaction Method ◽  
Physical Parameters ◽  
Nominal Composition ◽  
Electric Response ◽  
Metallic Behavior ◽  
High Dielectric ◽  
Semiconducting Behavior

Samples with the nominal composition Bi 2 Sr 2 SmCu 2 O y were prepared by solid state reaction method. From the room temperature X-ray diffraction data, it was found that the sample is similar to the Bi-2212 structure. DC electrical resistivity was done from 80 K to 573 K and the impedance measurements were performed from 80 K to 573 K at different frequencies in the range of 10 kHz to 800 kHz. The sample Bi 2 Sr 2 SmCu 2O y has exhibited semiconducting behavior in the low temperature region (80 K to 343 K), metallic behavior in the temperature range of 343 K to 443 K and again semiconducting behavior above 443 K. The sample has exhibited the phenomenon of variable rangehopping mechanism (VRH). The physical parameters related to VRH such as localization length (a), hopping distance (R) and hopping energy (W) have been evaluated and discussed. The activation energy in the high temperature region (above 300 K) decreases with increasing frequency. Tan δ increases with increase in temperature (303 K-573 K), which is attributed to increased conductivity. The dielectric constant increases with increase in temperature. For a given temperature the value of ε is found to decrease with increase in frequency.

scholarly journals Dielectric studies and microwave emissivity of alkaline soil of Alwar with mixing of gypsum

2010 ◽  
Vol 7 (2) ◽  
pp. 519-524
Author(s):  
V. K. Gupta ◽  
R. A. Jangid ◽  
Seema Yadav
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Dielectric Properties ◽  
Soil Moisture Content ◽  
Microwave Frequency ◽  
Alkaline Soil ◽  
Dielectric Studies ◽  
Horizontal Polarization ◽  
Microwave Emissivity ◽  
Percentage Concentration

The real and imaginary parts of dielectric constant (ε' and ε") of alkaline soil of Alwar with mixing of gypsum (0.0% to 10.0%, gravimetrically) determined at 34.50C temperature and at a single microwave frequency 9.78 GHz by wave guide cell method. Mixture of soil and gypsum is prepared at various moistness of soil varying from 0.0% to 12.0%. The ε' and ε" of gypsum are also determined. It was observed that ε' and ε" increases as percentage concentration of gypsum in the soil increase. It was observed that the effect of gypsum mixing on dielectric properties is more significant at higher level of soil moisture content. Further, microwave emissivities are estimated from measured values of ε' and ε" for dry and wet mixture of, soil and gypsum at various observation angles (00-800) for horizontal polarization. It was observed that emissivity of soil decreases as the percentage concentration of gypsum in the soil increases.

The Metallic State of Conducting Polymers: Microwave Dielectric Response and Optical Conductivity

1993 ◽  
Vol 328 ◽  
Author(s):  
A. J. Epstein ◽  
J. Joo ◽  
R. S. Kohlman ◽  
A. G. Macdiarmid ◽  
J. M. Weisinger ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Conducting Polymers ◽  
Three Dimensional ◽  
Microwave Frequency ◽  
Linear Increase ◽  
Metallic State ◽  
Microwave Dielectric ◽  
Conducting Polyaniline ◽  
New Generation ◽  
Domain Length

ABSTRACTRecent advances in processing of polyaniline and polyacetylene have resulted in a new generation of conducting polymers with higher dc conductivities. We present the temperature (T) dependent microwave frequency dielectric constant, dc conductivity, and Kramers-Kronig analysis of conducting polyaniline and polyacetylene. The low temperature dielectric constant, ε, increases with the square of the x-ray crystalline domain length for preparations of HCl protonated polyaniline. For the highest crystalline polyaniline samples, ε increases dramatically with increasing T, supporting formation of three-dimensional (3-D) coupled “mesoscopic” Metallic regions. A “metallic” negative ε is observed for d,1-camphor sulfonie acid doped polyaniline prepared in m-cresol. Optical studies show a linear increase in reflectivity below 7000 cm-1. Below 600 cm-1 the reflectance increases rapidly. Kramers-Kronig analysis of the ir-visible results are presented. Highly conducting polyaniline is shown to have two plasma frequencies, one at ∼ 1.1 eV involving all the conduction band electrons, and one at ∼0.015 eV (120 cm-1) that is suggested to arise from the most delocalized electrons. The concept of inhomogeneous disorder is introduced. The results for polyaniline are compared to those of highly doped polyacetylene which also show metallic negative ε demonstrating the intrinsic metallic nature of the new generation of conducting polymers.

STUDIES ON ORIENTED DOMAIN POLYSTYRENE-TGS COMPOSITE FILMS

1995 ◽  
Vol 09 (17) ◽  
pp. 1039-1044
Author(s):  
S.C. MATHUR ◽  
D.S. RAWAT ◽  
H.O. YADAV ◽  
D.C. DUBE ◽  
A.S. BHALLA
Keyword(s):  
Dielectric Constant ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Domain Structure ◽  
Spontaneous Polarization ◽  
Coercive Field ◽  
Composite Films ◽  
Microwave Frequency ◽  
Ferroelectric Films ◽  
Microwave Frequencies

Polymer ferroelectric films were prepared by dispersing TGS powder in polystyrene. Permittivity versus temperature plots exhibit a peak at around the transition temperature of TGS. The peak gets suppressed with increasing frequency and the trend continues up to microwave frequencies. We observed that the dielectric constant of films at microwave frequency stays close to the dielectric constant of polystyrene. The domain structure of TGS crystals essentially seems to affect their dielectric properties. Single domain films exhibit a higher spontaneous polarization and a higher coercive field.

scholarly journals Dielectric Constant, Metallization Criterion and Optical Properties of CuO Doped TeO2-B2O3 Glasses

2021 ◽  
Author(s):  
NAZIRUL NAZRIN SHAHROL NIDZAM ◽  
S.A. Umar ◽  
M.K. Halimah ◽  
M.M. Marian ◽  
Z.W. Najwa ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Molar Volume ◽  
Copper Ion ◽  
Volume Density ◽  
Dielectric Constants ◽  
Physical Parameters ◽  
Laser Applications ◽  
Optical Dielectric Constant ◽  
Ftir Spectral Analysis

Abstract Copper oxide doped TeO2 – B2O3 glass system with empirical formula; [(B2O3)0.3(TeO2)0.7]1-x(CuO)x using the melt quenching method, where x = 0.0, 0.01, 0.015, 0.02, and 0.025 was combined. The glass samples’ density and molar volume were measured, followed by characterizations using the UV-Vis, Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopes. The amorphous or glassy nature of glass samples was proven by the XRD spectra except for the pure borotellurite sample which showed a peak around 2θ = 20o, indicating α-TeO2 crystalline phase presence. The FTIR spectral analysis suggested the presence of BO3, TeO3 and TeO4 as the structural functional units in the glass samples. The UV-Vis spectra showed no presence of any sharply defined edges, affirming the amorphous or glassy nature of the glass materials. Physical parameters e.g. molar volume, density, oxygen packing density (OPD), inter ionic distance of Cu2+ ions, concentration of copper ion per unit volume (N), as well as the polaron radius data were presented and discussed. Also, the direct bandgap (3.8900 to 3.5900 eV) , indirect bandgap (3.3200 to 3.0800 eV), refractive index (2.318 to 2.378), dielectric constant (5.3731 to 5.6549), optical dielectric constant (4.3731 to 4.6549), refractive index based metallization criterion (0.406885 to 0.391916) and the band gap based metallization criterion (0.407431 to 0.392428) were analysed and discussed. Based on the metallization criterion and values of refractive index, the glasses are good candidates for optoelectronic and laser applications. Meanwhile, the dielectric constants’ values of the present glasses indicate their suitability bandpass filters and microelectronic substrates applications.

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