THE DIELECTRIC CONSTANT OF BROMINE AT MICROWAVE FREQUENCIES

1967 ◽  
Vol 45 (7) ◽  
pp. 2349-2354 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
R. P. Doble
Keyword(s):  
Dielectric Constant ◽  
Loss Tangent ◽  
Optical Range ◽  
Frequency Range ◽  
Improved Method ◽  
Microwave Frequencies ◽  
The Real ◽  
Liquid Bromine ◽  
Tan Δ

Measured values of the real part of the dielectric constant, ε′, and the loss tangent, tan δ, of liquid bromine at 20 °C in the frequency range 8.2–18 GHz are presented. The results for tan δ were obtained by a previously described technique; the results for ε′ were obtained by an improved method herein described. A suggested mechanism for absorption is discussed and the results related to static values and values in the optical range.

THE COMPLEX DIELECTRIC CONSTANT AT LOW MICROWAVE FREQUENCIES OF ETHYL CHLORIDE ADSORBED ON POROUS VYCOR GLASS

1961 ◽  
Vol 39 (3) ◽  
pp. 425-442 ◽  
Author(s):  
J. D. McCowan ◽  
R. McIntosh
Keyword(s):  
Dielectric Constant ◽  
Coaxial Line ◽  
Ethyl Chloride ◽  
Complex Dielectric Constant ◽  
Frequency Range ◽  
Vycor Glass ◽  
Microwave Frequencies ◽  
The Real ◽  
Porous Vycor Glass ◽  
Accuracy Of Measurement

The complex dielectric constant of the system Vycor glass – ethyl chloride has been measured at three temperatures in the range +11 °C to −33 °C and in the frequency range between 500 Mc sec−1 and 4000 Mc sec−1 by the use of a coaxial line. The real and imaginary parts of the dielectric constant of the adsorbate have also been evaluated. Appreciable loss in the adsorbed matter is found for small quantities adsorbed, and loss is again detected at the highest frequencies and lowest temperatures for the matter held in multilayers or condensed in capillaries. The frequency range and accuracy of measurement were not sufficient to classify the type of loss curve, but other evidence suggests that the loss for the first quantities adsorbed will turn out to be that for rotational oscillators. In general earlier observations of this system are confirmed and extended.

TRANSPORT PROPERTIES OF THERMALLY EVAPORATED In2Se3 THIN FILMS

2009 ◽  
Vol 16 (05) ◽  
pp. 723-729 ◽  
Author(s):  
D. NITHYAPRAKASH ◽  
B. PUNITHAVENI ◽  
J. CHANDRASEKARAN
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Ac Conductivity ◽  
Thermal Evaporation ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Cbh Model ◽  
X Ray ◽  
Correlated Barrier Hopping ◽  
Tan Δ

Thin films of In2Se3 were prepared by thermal evaporation. X-ray diffraction indicated that the as-grown films were amorphous in nature and became polycrystalline γ-In2Se3 films after annealing. The ac conductivity and dielectric properties of In2Se3 films have been investigated in the frequency range 100 Hz–100 kHz. The ac conductivity σ ac is found to be proportional to ωn where n < 1. The temperature dependence of both ac conductivity and the parameter n is reasonably well interpreted by the correlated barrier hopping (CBH) model. The values of dielectric constant ε and loss tangent tan δ were found to increase with frequency and temperature. The ac conductivity of the films was found to be hopping mechanism. In I–V characteristic for different field and temperature were studied and it has been found that the conduction process is Poole–Frenkel type.

Microwave Electromagnetic Characteristics of a Microcoiled Carbon Fibers/paraffin Wax Composite in Ku Band

2002 ◽  
Vol 17 (5) ◽  
pp. 1232-1236 ◽  
Author(s):  
Jin-Hong Du ◽  
Chao Sun ◽  
Shuo Bai ◽  
Ge Su ◽  
Zhe Ying ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Loss Tangent ◽  
Relative Permittivity ◽  
Magnetic Loss ◽  
Attenuation Factor ◽  
Paraffin Wax ◽  
The Real ◽  
Tan Δ ◽  
Factor Α ◽  
Ku Band

The complex relative permittivity ∈γ and permeability μγ of microcoiled carbon fibers (MCCFs) imbedded in paraffin wax were measured at Ku band frequencies (12.4–18 GHz). Both the real and imaginary parts of the complex relative permittivity of the MCCFs/paraffin wax composite decreased with increase of the frequency. The real part of the complex relative permeability of the composite increases with increase of the frequency, and the imaginary part is nonzero and nearly constant over the measured frequency range. The dielectric loss tangent (tan δ∈), the magnetic loss tangent (tan δm), and amplitude attenuation factor (α) were determined as well. On the basis of the experimental results, the MCCFs/paraffin wax composite is mainly a kind of dielectric lossy material with small magnetic loss and diamagnetism in the Ku band.

AN INVESTIGATION ON THE DIELECTRIC PROPERTIES OF POLYANILINE-BASED NANOCOMPOSITE

2010 ◽  
Vol 24 (15) ◽  
pp. 1669-1674
Author(s):  
J. JIANG ◽  
L. H. AI
Keyword(s):  
Dielectric Properties ◽  
Imaginary Part ◽  
Complex Permittivity ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
Dissipation Factor ◽  
Frequency Range ◽  
The Real ◽  
Tan Δ

Polyaniline/ LiNi 0.5 Gd 0.08 Fe 1.92 O 4 nanocomposite was synthesized by an in-situ polymerization of aniline in the presence of LiNi 0.5 Gd 0.08 Fe 1.92 O 4 particles. The dielectric properties of the as-prepared polyaniline-based nanocomposite were investigated using an Agilent E4991A RF Impedance/Material Analyzer at room temperature in the frequency range from 1 MHz to 1 GHz. The real (ε') and imaginary part (ε″) of complex permittivity, and dissipation factor ( tan δ) were found to be frequency-dependent, which decreased with increasing of frequency. It was shown that ε', ε″ and tan δ of the nanocomposite were lower than those of pristine polyaniline. In order to investigate the dielectric process in detail, the complex electric modulii derived from the complex permittivity were analyzed as a function of the frequency.

scholarly journals CHARGE CARRIERS TRANSPORT AND PERMITTIVITY OF SIO2 FILMS WITH INSB NANOPARTICLES

2020 ◽  
Author(s):  
Pawel Zukowsk ◽  
Tomasz Koltunowicz ◽  
Karolina Czarnacka ◽  
Alexander Fedotov ◽  
Ida Tyschenko
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Phase Angle ◽  
Exponential Decay ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Charge Carriers ◽  
Complex Dielectric Constant ◽  
Sio2 Films ◽  
The Real

A.c. current conductivity, capacitance, phase angle and dielectric loss tangent were studied for MOS SOI structures with ion-synthesized in the buried SiO2 layer InSb nanoparticles. Films conductivity nature change was detected at the temperature Т=200К. An exponential decay of the real and imaginary parts of the films complex dielectric constant was found.

Comparison of Dielectric Properties of Traditional and High-Oleic Runner-Type Peanuts at Microwave Frequencies

2021 ◽  
Vol 64 (6) ◽  
pp. 1817-1822
Author(s):  
Micah A. Lewis ◽  
Samir Trabelsi
Keyword(s):  
Dielectric Constant ◽  
Oleic Acid ◽  
Linoleic Acid ◽  
Dielectric Properties ◽  
Moisture Content ◽  
Loss Tangent ◽  
Loss Factor ◽  
Microwave Frequencies ◽  
High Oleic ◽  
Transmission Measurements

HighlightsPermittivity measurements were taken for traditional and high-oleic runner-type peanut pods and kernels at microwave frequencies.The dielectric constant, loss factor, loss tangent, and complex plane were compared between the two cultivars to observe any effect caused by the high-oleic trait.Despite differences in composition, minimal to no differences were observed in permittivity between the two cultivars.Abstract. Different cultivars of peanuts containing higher amounts of oleic acid have been developed to improve oxidative stability and overall peanut quality. Increasing oleic acid levels and decreasing linoleic acid levels in peanuts deter lipid oxidation, preventing the creation of off-flavors and increasing the shelf life. Since their conception, high-oleic peanuts have been tested from chemical and sensory perspectives to observe differences between them and traditional peanuts. Such tests have shown minimal differences, if any. However, tests to observe the effect of changing the levels of oleic and linoleic acid on permittivity, which is often used for nondestructive determination of the moisture content and bulk density of foods and agricultural products, have not been reported. Thus, a vector network analyzer (VNA) was used to take free-space transmission measurements of the complex permittivities of high-oleic and traditional runner-type peanut pods and kernels. Measurements were taken at 23°C between 5 and 9 GHz. Measurements yielded the dielectric constant and loss factor, which are often correlated to moisture content. Analysis was performed to compare the changes in the dielectric constant, loss factor, and loss tangent with moisture content for high-oleic and traditional peanuts. Linear trends were observed for each parameter with increasing moisture content for both cultivars. Results from the complex plane showed coefficient of determination (r2) values greater than 0.9 for pods and kernels. Therefore, at microwave frequencies, changing the levels of oleic and linoleic acid within the peanuts was observed to have minimal to no effect on their permittivity. Thus, moisture calibrations based on correlations between dielectric properties and moisture content for traditional runner-type peanuts can be applied to high-oleic cultivars. Keywords: Dielectric properties, Free-space transmission measurements, Microwave measurements, Oleic acid, Peanut kernels, Peanut pods.

SrxBa(1−x)TiO3 Thin Films for Active Microwave Applications

1994 ◽  
Vol 361 ◽  
Author(s):  
J.S. Horwitz ◽  
J.M. Pond ◽  
B. Tadayan ◽  
R.C.Y. Auyeung ◽  
P.C. Dorsey ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Loss Tangent ◽  
Rocking Curve ◽  
Microwave Frequencies ◽  
X Ray ◽  
Interdigital Capacitor ◽  
Frequency Tunable ◽  
Film Dielectric ◽  
Substrate Temperatures

ABSTRACTThe dielectric constant, loss tangent and Curie temperature for SrxBa(1−x)TiO3 (SBT) thin films with x = 0.2 – 0.8 have been investigated at microwave frequencies. SBT films (0.5 -3 μm thick) were grown on (100) MgO and LaAlO3 substrates by pulsed laser deposition at substrate temperatures from 850 – 900 °C in 0.35 Torr of oxygen. Deposited ferroelectric films were single phase, highly oriented, and characterized by x-ray rocking curve widths of < 0.5°. Highly oriented SBT films with x-ray rocking curve widths of 72 arc seconds were observed. In general, the thin film dielectric constant at microwave frequencies is low (200–950) compared to the reported bulk value, but strongly dependent on the Sr/Ba ratio. Biasing of a ferroelectric interdigital capacitor (< 200 kV/cm) produces a change in the dielectric constant which resulted in a phase shift in the reflected signal (S11) measured as a function of frequency from 100 MHz to 10 GHz. The dielectric loss tangent measurement, as measured at room temperature and 9.2 GHz, ranges from 0.1 to 1.2 × 10−3 and depends on the Sr/Ba ratio. These data show that SBT thin films are suitable for the development of frequency tunable microwave circuits and components.

THE DIELECTRIC PROPERTIES OF SELECTED BASALTS

Geophysics ◽  
1973 ◽  
Vol 38 (1) ◽  
pp. 135-139 ◽  
Author(s):  
W. Hansen ◽  
W. R. Sill ◽  
S. H. Ward
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
Frequency Dispersion ◽  
Nitrogen Atmosphere ◽  
Frequency Range ◽  
Dielectric Constant And Loss ◽  
Identical Composition ◽  
Titanium Compounds

Basaltic samples of known chemical composition were measured for dielectric constant and loss tangent in the frequency range 100 hz to 50 Mhz. All samples were prepared and measured by a contact substitution method in a dry nitrogen atmosphere at room temperature. The measurements indicated a general spectrum of dielectric constant with a range of 10–65 at 100 hz to 7–15 at 50 Mhz with frequency dispersion observed to be minimal above 1 Mhz. The loss tangent decreases from a range .2–.9 at 100 hz to a range .02–.15 at 100 khz. A finer‐grained sample was observed to have higher dielectric properties below 1 Mhz than a coarser‐grained sample of identical composition. A qualitative and subsequent quantitative study of possible compositional effects indicated that iron‐titanium compounds may be responsible for observed variations in the dielectric spectra of typical basalts.

DIELECTRIC PROPERTIES OF Li-Sb FERRITES

2005 ◽  
Vol 19 (18) ◽  
pp. 899-905 ◽  
Author(s):  
SHIVAJI CHONGTHAM ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA ◽  
RADHAPIYARI LAISHRAM ◽  
CHANDRA PRAKASH
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Room Temperature ◽  
Substitution Level ◽  
Higher Temperature ◽  
Tan Δ ◽  
Almost All ◽  
Frequency Curves

Dielectric properties such as dielectric constant (ε′) and dielectric loss tangent ( tan δ) of Li 0.5+x Fe 2.5-2x Sb x O 4 ferrites, 0.10≤ x ≤0.30 in steps of 0.05 have been investigated as a function of composition, frequency and temperature. The dielectric constant showed dispersion with frequency in the range of 100 Hz–1 MHz. Peaks were observed in the tan δ versus frequency curves for almost all the samples. The temperature variation of dielectric constant for the different samples was studied at 10 kHz in the temperature range from room temperature to 433 K. Peaks were observed for some of the samples. The peaks were seen to shift towards higher temperature region as the substitution level increases. The mechanisms involved in the processes are discussed in this paper.

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