Dielectric Constant of SbSI Single Crystals on the Frequency of 9.3 Gc/s Observed by Means of a Reflection Coefficient

1969 ◽  
Vol 27 (2) ◽  
pp. 513-514 ◽  
Author(s):  
Hideo Iwasaki
Keyword(s):  
Dielectric Constant ◽  
Reflection Coefficient ◽  
Single Crystals

scholarly journals Estimation of optical parameters of silicon single crystals with different orientations

2019 ◽  
Vol 37 (1) ◽  
pp. 65-70
Author(s):  
M.M. El-Nahass ◽  
H.A.M. Ali
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Single Crystals ◽  
Energy Gap ◽  
Optical Parameters ◽  
Dispersion Energy ◽  
High Frequency Dielectric Constant ◽  
Single Oscillator Model ◽  
Indirect Allowed Transition ◽  
Single Oscillator

AbstractOptical properties of Si single crystals with different orientations (1 0 0) and (1 1 1) were investigated using spectrophotometric measurements in a spectral range of 200 nm to 2500 nm. The data of optical absorption revealed an indirect allowed transition with energy gap of 1.1 ± 0.025 eV. An anomalous dispersion in refractive index. The normal dispersion of the refractive index was discussed according to Wemple-DiDomenico single oscillator model. The oscillator energy Eo, dispersion energy Ed, high frequency dielectric constant ∈∞, lattice dielectric constant ∈L and electronic polarizability αe were estimated. The real ∈1 and imaginary ∈2 parts of dielectric constant were also determined.

A Hammer Type Textile Antenna With Partial Circle Ground for Wide-Band Application

2020 ◽  
pp. 15-24
Author(s):  
Anurag Saxena ◽  
Bharat Bhushan Khare
Keyword(s):  
Dielectric Constant ◽  
Reflection Coefficient ◽  
Patch Antenna ◽  
Wide Band ◽  
Simulation Tool ◽  
Textile Antenna ◽  
Partial Circle ◽  
Maximum Directivity

In this chapter, a partial circle ground textile patch antenna for wideband applications with better bandwidth is presented. The simulated antenna is proposed on textile jeans substrate having dielectric constant of 1.7. The radius of textile jeans substrate antenna is 15 mm. The overall simulation of partial circle grounded shaped antenna has been done using CST simulation tool. The simulated antenna resonates at frequency 9.285 GHz with the reflection coefficient of -28 dB. It covers a bandwidth from 7.008 GHz to 9.64 GHz. It has maximum directivity of 4.540 dBi.

GROWTH AND STUDIES OF PROPERTIES OF COPPER SUCCINATE DIHYDRATE SINGLE CRYSTALS

2013 ◽  
Vol 27 (11) ◽  
pp. 1350073
Author(s):  
M. P. BINITHA ◽  
P. P. PRADYUMNAN
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Single Crystals ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Different Temperatures ◽  
Triclinic Structure ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Single crystals of copper succinate dihydrate (CSD) with triclinic structure were grown in silica gel medium. The functional groups in the crystal were analyzed by FT-IR Spectroscopy. Atomic Force Microscopy (AFM) revealed the striations on the surface of grown crystals, which were incorporated during its time of growth. Thermal degradation studies have been carried out by Differential Scanning Calorimetry (DSC). Dielectric constant and AC conductivity have been estimated as a function of frequency at different temperatures.

scholarly journals Radio Echo Sounding of Horizontal Layers in Ice

1973 ◽  
Vol 12 (66) ◽  
pp. 383-397 ◽  
Author(s):  
C. H. Harrison
Keyword(s):  
Dielectric Constant ◽  
Reflection Coefficient ◽  
Ice Crystals ◽  
Fractional Change ◽  
Dielectric Absorption ◽  
Radio Echo Sounding ◽  
The Antarctic ◽  
Horizontal Layers ◽  
Effective Reflection Coefficient ◽  
Echo Sounding

Radio echo-sounding surveys of Antarctica and Greenland have revealed extensive layering within the ice. Formulae for the effective reflection coefficient, when viewed by a pulsed radar, are derived for isolated or multiple randomly spaced layers. In the latter case the variation in dielectric constant with depth is described by a vertical autocorrelation function and a standard deviation. Some measurements of the reflection coefficient of layers, and the dielectric absorption of ice are given. The significance of the fading of layer echoes and the possible causes of variations in the dielectric constant are considered and some further investigations are suggested. It is concluded that the echo strengths found in the Antarctic may be explained by multiple layering, and that the necessary fractional change in the dielectric constant may be as small as 10−4. It is suggested that this change in dielectric constant may be due to differences in orientation of anisotropic ice crystals.

Electrical tuning of metastable dielectric constant of ferroelectric single crystals for low-power electronics

2011 ◽  
Vol 99 (18) ◽  
pp. 182903 ◽  
Author(s):  
Mingqiang Bao ◽  
Alexandre Bur ◽  
Hyungsuk K.D. Kim ◽  
Kotekar P. Mohanchandra ◽  
Christopher S. Lynch ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Low Power ◽  
Power Electronics ◽  
Single Crystals ◽  
Low Power Electronics

scholarly journals Growth, Optical and Dielectric Studies on Pure and L-Lysine Doped KDP Crystals

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
N. Kanagathara ◽  
G. Anbalagan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Single Crystals ◽  
Visible Region ◽  
Point Of View ◽  
Dielectric Study ◽  
Dielectric Studies ◽  
Slow Evaporation ◽  
Application Point ◽  
Kdp Crystals

Optically good quality single crystals of pure and L-lysine monohydrochloride-doped KDP crystals have been grown by a slow evaporation method. The grown crystals have been subjected to optical and dielectric studies. The UV-Vis spectrum shows the transmitting ability of the crystals in the entire visible region and transmittance percentage is increased for the doped KDP crystals. From the dielectric study, it is found that the dielectric constant and the dielectric loss of L-lysine-doped KDP crystals were lower than the pure KDP crystals. Hence L-lysine-doped KDP crystals are found to be more beneficial from an application point of view as compared to pure KDP crystals.

Radio-wave reflectivity from cold glaciers

2020 ◽  
Author(s):  
Olga Yushkova ◽  
Taisiya Dymova ◽  
Viktor Popovnin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Permittivity ◽  
Reflection Coefficient ◽  
Surface Temperature ◽  
Frequency Dependence ◽  
Depth Profile ◽  
Loss Tangent ◽  
Thin Layers ◽  
The Arctic ◽  
Radio Waves

<p>Radio echo-sounding is a powerful technique for investigating the subsurface of the glaciers. However, physics underlying the formation of the reflected signal is sometimes oversimplified  in the geophysical glacier studies, leading to wrong results. Various remote sensing techniques use different wavelengths (e.g., 13.575 GHz for CryoSat and 20-25/200-600 MHz for ground-penetrating radar), but it is still not clear which particular wavelengths are the best to detect different characteristics of the ice. Possibly, the results gained using different wavelengths may not coincide but rather complement each other due to frequency dependence of the dielectric permittivity and conductivity of snow, ice and especially water.</p><p>Here we attempt to construct an electrophysical model of a cold glacier. This mathematical model considers the variability of the depth profile of the complex dielectric permittivity depending on the frequency of the probing radio signal and the surface temperature. A series of calculations of the reflection coefficients of radio waves from the modelled glacier show that at low temperatures for frequencies above 1 MHz the real part of the dielectric constant of the glacier does not change with frequency and surface temperature, but depends on the glacier structure, while the depth profile of the loss tangent is constant throughout the glacier.  As wavelength decreases, the absorption of radio-waves by the glacier decreases and the frequency dependence of the reflection coefficient becomes a periodic function, its period and amplitude depend on the glacier thickness, the dielectric constant of the bedrock and ice on the surface.</p><p>The range of radio-waves from 0.1 to 1 MHz is not optimal for sounding cold glaciers: the absorption of radio-waves by ice is large for studying thick layers of the glacier, and the wavelength does not allow studying thin layers. Hence, reflection from the glacier surface prevails upon reflection of the signal. The small absorption of short radio waves by ice leads to the fact that the frequency dependence of the reflection coefficient of short radio-waves is practically the sum of the partial reflections of radio-waves from the surface and internal snow/firn and firn/ice boundaries. Period and amplitude of oscillations of the function  depend on the depth of the internal boundaries and the gradient of dielectric characteristics of ice, snow, firn and bedrock.</p><p>Changes in surface temperature, leading to a change in the loss tangent of the upper glacier layers, are manifested in the phase magnitude of the reflection coefficient of radio-waves:it grows with the temperature. Theoretically, the high-frequency signal reflected from the glacier contains information about the structure of the cold glacier and the depth distribution of the dielectric constant, but to restore the electrophysical parameters of the glaciers, it is necessary to use a broadband signal with smooth spectrum and high digitization speed.</p><p>The reported study was funded by RFBR, project number 18-05-60080 (“Dangerous nival-glacial and cryogenic processes and their impact on infrastructure in the Arctic”).</p>

The dielectric constant of TCNQ single crystals as deduced by reflection electron energy loss spectroscopy

1993 ◽  
Vol 8 (10) ◽  
pp. 2627-2633 ◽  
Author(s):  
G. Mondio ◽  
F. Neri ◽  
G. Curró ◽  
S. Patané ◽  
G. Compagnini
Keyword(s):  
Dielectric Constant ◽  
Energy Loss ◽  
Energy Range ◽  
Single Crystals ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Incidence Angle ◽  
Low Energy ◽  
Wide Energy Range ◽  
Electron Energy Loss

The dielectric constant of tetracyanoquinodimethane (TCNQ) single crystals has been obtained by reflection electron energy loss spectroscopy (REELS) over the 0–60 eV energy range, using primary electron energies ranging from 0.5 to 1.5 keV at an incidence angle of about 40°. A self-consistent method is discussed concerning the evaluation of the surface and bulk contributions to the loss spectra. As a result, for the first time, the Im(−1/∊) function and the dielectric constant of TCNQ have been deduced in such a wide energy range. According to the results obtained by other authors, the low-energy loss spectral profile is characterized by two main structures ascribed to the π → π∗ dipole-allowed transitions located at about 3.5 and 6.5 eV while, at higher energy loss, the π + σ plasmon, centered at about 21.5 eV, dominates the spectrum. The differences among the spectra taken at different primary energies are interpreted as due only to surface effects, more evident in the low-energy-loss spectral region. The results are in good agreement with those obtained by recent transmission-mode (TEELS) experiments.

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