scholarly journals Identification of the complex relative dielectric constant of porous polymers at different degrees of humidity

2008 ◽  
Vol 6 ◽  
pp. 5-8 ◽  
Author(s):  
K. Haake ◽  
J. L. ter Haseborg
Keyword(s):  
Dielectric Constant ◽  
Cylindrical Shell ◽  
Relative Dielectric Constant ◽  
Porous Polymers ◽  
Scattering Parameters ◽  
Frequency Range ◽  
Climate Chamber ◽  
Temperature And Humidity ◽  
Climate Interactions ◽  
Rf Measurements

Abstract. In order to investigate the complex relative dielectric constant of different materials over a frequency range of 50 MHz to 3 GHz a setup has been built that allows rf-measurements in a climate chamber. Within this chamber the temperature and humidity can be changed and be measured by accurate sensors. The construction of the rf-part of the setup has been made with an outer cylindrical shell that allows climate interactions through its large orifices. Methods for calculating the complex relative dielectric constant from the measured scattering parameters are presented and the changes of the relative constants due to different humidity conditions are shown.

Relative dielectric constant of epitaxial BaTiO3 thin films in the GHz frequency range

2003 ◽  
Vol 83 (25) ◽  
pp. 5274-5276 ◽  
Author(s):  
T. Hamano ◽  
D. J. Towner ◽  
B. W. Wessels
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Relative Dielectric Constant ◽  
Frequency Range

Dielectric and structural properties of iron- and sodium-fumarates

2012 ◽  
Vol 36 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Sonja Skuban ◽  
Tanja Džomié ◽  
Agneš Kapor ◽  
Željka Cvejić ◽  
Srđan Rakic
Keyword(s):  
Dielectric Constant ◽  
Ionic Conductivity ◽  
Structural Properties ◽  
Ac Conductivity ◽  
Loss Factor ◽  
Low Frequency ◽  
Relative Dielectric Constant ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Increasing Temperature

Abstract The behaviour of dielectric parameters such as the relative dielectric constant (ε''), the relative loss factor (ε'') and the ac conductivity of well known pharmaceutical materials Fe(II)-fumarate and Na-fumarate were studied as a function of temperature (in the range from 303K to 483 K) and frequency (in the range from 0.1 Hz to 100 kHz). The values of the conductivity are in the range of 10−5 Ω−1m−1 to 10−9 Ω−1m−1 for Fe(II)-fumarate and 10−6 Ω−1m−1 to 10−11 Ω−1m−1 for Na-fumarate. The conductivity of both materials increases with the increase in temperature and frequency. It was found that both ε' and ε'' decrease with increasing frequency and increase with increasing temperature for both materials. The highest changes are in the low frequency range. The obtained values of the dielectric parameters and conductivity suggest that these materials are dielectric with similar structure, most probably polymeric, with the mechanism of ionic conductivity.

Effect Of Moisture On The Physical Properties Of Polyimide Films

1991 ◽  
Vol 227 ◽  
Author(s):  
Rajeevi Subramanian ◽  
Michael T. Pottiger ◽  
Jacqueline H. Morris ◽  
Joseph P. Curilla
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Electrical Properties ◽  
Relative Humidity ◽  
Quartz Crystal ◽  
Moisture Absorption ◽  
Relative Dielectric Constant ◽  
Moisture Uptake ◽  
Polyimide Films ◽  
Effect Of Moisture

ABSTRACTMoisture absorption and its effect on electrical properties were measured for several polyimides. A Quartz Crystal Microbalance (QCM) was used to investigate the moisture absorption in BPDA/PPD, PMDA/ODA, and BTDA//ODA/MPD polyimides. The steady-state moisture uptake in polyimides as a function of relative humidity (RH) was determined by exposing film samples to successively higher RH values ranging from 10 to 85% at 25°C. The isothermal moisture absorption as a function of percent RH was found to be nearly linear for all of the polyimides studied. The effect of moisture on the electrical properties of a BPDA/PPD polyimide was also investigated. The relative dielectric constant at 25 °C was found to be a linear function of the moisture absorbed.

The Research on the Piezoelectric and Dielectric Properties of Bi0.5(Nak)0.5-BaTiO3 Lead-Free Ceramics

2014 ◽  
Vol 1035 ◽  
pp. 422-425
Author(s):  
Jian Yong Guo ◽  
Tao Sheng Zhou ◽  
Ji Hong Liao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Relative Dielectric Constant ◽  
Lead Free ◽  
Reactive Sintering ◽  
Lead Free Ceramics ◽  
Xrd Patterns ◽  
Sintering Method

The Bi0.5(Na1-xKx)0.5-yBaTiO3(BNK-BT) lead-free ceramics have been prepared by the solild reactive sintering method. XRD patterns show the BNK-BT ceramics had a perovskite structure. Piezoelectric and dielectric properties of the ceramics also have been studied. The results show that the samples had the best piezoelectric and dielectric properties when x=0.20, y=0.10. And the maximum of d33is 149 pC/N, while the relative dielectric constant is 1087.

The Processing and Properties of Multilayer Interconnection Structures Using Thermoset Films Derived from Bisbenzocyclobutene.

1989 ◽  
Vol 154 ◽  
Author(s):  
P. H. Townsend ◽  
D. C. Burdeaux ◽  
S. F. Hahn ◽  
M. Thomsen ◽  
J. N. Carr
Keyword(s):  
Dielectric Constant ◽  
Thermal Cycling ◽  
Relative Dielectric Constant ◽  
Electrical Characteristics ◽  
Processing Conditions ◽  
Dielectric Layers ◽  
Significant Change

AbstractMultilayer interconnection structures incorporating a novel polymeric dielectric derived from a bis-benzocyclobutene(bis-BCB) monomer have been fabricated. This paper discusses the processing conditions for the construction of these circuits and describes electrical characteristics of the dielectric layers. The relative dielectric constant of the BCB film was 2.7. Thermal cycling produced no significant change in the conductance of three level metal via chains through two layers of the polymer.

scholarly journals Experimental Study on the Icing Dielectric Constant for the Capacitive Icing Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3325
Author(s):  
Yongcan Zhu ◽  
Xinbo Huang ◽  
Yi Tian ◽  
Chao Ji ◽  
Wen Cao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dielectric Constant ◽  
Test Temperature ◽  
Reference Value ◽  
Relative Dielectric Constant ◽  
Capacitive Sensor ◽  
Fundamental Parameters ◽  
Detection Technology ◽  
Capacitive Method ◽  
Characteristic Values

The capacitive method is considered to be a suitable icing-detection technology, but the lack of fundamental parameters restricts the development of icing-detection sensors. In this paper, an artificial icing laboratory, a capacitive sensor, and some simulation conductors have been designed for obtaining the artificial icing samples. Subsequently, the same characteristic values of artificial icing have been measured by an LCR device, under a selected frequency. This research found that the value of the icing dielectric constant closely correlated with its density, internal sublayer, and the test temperature. Finally, a fitting formula has been presented for calculating the relative dielectric constant, which may provide some important reference value for the design of icing-detection sensors.

scholarly journals Análisis cristalográfico, morfológico, eléctrico, óptico y magnético del nuevo material Dy2BiFeO6

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Jairo Roa-Rojas
Keyword(s):  
Dielectric Constant ◽  
Energy Gap ◽  
Magnetic Hysteresis ◽  
Magnetic Ordering ◽  
Relative Dielectric Constant ◽  
Double Perovskite ◽  
Crystallographic Analysis ◽  
Weiss Temperature ◽  
Constant E ◽  
Diffraction Patterns

We report structural analysis, surface morphology, magnetic ordering, dielectric response, optical feature and the electronic structure of the Dy2BiFeO6 novel complex perovskite. The samples were produced by the standard solid-state reaction recipe. Crystallographic analysis was performed by Rietveld refinement of experimental X-ray diffraction patterns. Results show that this material crystallizes in a perovskite with orthorhombic structure, which corresponds to the Pnma (#62) space group. From the Curie-Weiss fitting on the curve of susceptibility as a function of temperature we establish that the ordering corresponds to a paramagnetic-antiferromagnetic transition, with a Weiss temperature q=-18,5 K, which is compatible with the behavior of the inverse of susceptibility as a function of temperature, and a Néel temperatura TN=50,8 K. The Curie constant allowed for us to obtain an effective magnetic moment of 15,7 mB. The result of magnetization as a function of the applied field, measured at T=50 K, shows a magnetic hysteresis behavior that corroborate the magnetic ordering present for this temperature value. Measurements of the dielectric constant as a function of applied frequencies at room temperature give as a result a high relative dielectric constant (e=780). The reflectance curve as a function of the wavelength reveals the typical behavior of a double perovskite-like material and permits to obtain the energy gap 2,74 eV, which is characteristic of a semiconductor material.

scholarly journals Estimation of S-parameters and dielectric permittivity of quartz ceramics samples in millimeter waveband

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 65-71
Author(s):  
N. A. Pevneva ◽  
D. A. Kondrashov ◽  
A. L. Gurskii ◽  
A. V. Gusinsky
Keyword(s):  
Dielectric Constant ◽  
Dielectric Permittivity ◽  
Ceramic Materials ◽  
Reflection And Transmission Coefficients ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Higher Order Modes ◽  
S Parameters ◽  
The Fourier Transform

A modified Nicholson – Ross – Weir method was used to determine complex parameters and dielectric permittivity of ceramic materials in the range 78.33–118.1 GHz. The measuring equipment is a meter of complex reflection and transmission coefficients, a waveguide measuring canal with a special measuring cell, consisting of two irregular waveguides and a waveguide chamber between them, which provides insignificant influence of higher-order modes. The dependences of the amplitude and phase of the reflection and transmission coefficients on frequency were obtained experimentally for fluoroplastic and three ceramic samples in the frequency range 78.33–118.1 GHz. The obtained S-parameters are processed according to an algorithm that includes their averaging based on the Fourier transform in order to obtain the values of the dielectric permittivity. Fluoroplastic was used as a reference material with a known dielectric constant. The dielectric constant of fluoroplastic has a stable value of 2.1 in the above mentioned frequency range. The dielectric constant of sample No. 1 varies from 3.6 to 2.5 at the boundaries of the range, sample No. 2 – from 3.7 to 2.1, sample No. 3 – from 2.9 to 1.5. The experimental data are in satisfactory agreement with the literature data for other frequencies taking into account the limits set by the measurement uncertainty.

scholarly journals Detection and estimating the blood accumulation volume of brain hemorrhage in a human anatomical skull using a RF single coil

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10416
Author(s):  
Moshe Oziel ◽  
Boris Rubinsky ◽  
Rafi Korenstein
Keyword(s):  
Experimental Study ◽  
Electromagnetic Radiation ◽  
Hemorrhagic Stroke ◽  
Average Error ◽  
Tissue Fluid ◽  
Brain Hemorrhage ◽  
Scattering Parameters ◽  
Frequency Range ◽  
Single Coil ◽  
Chicken Blood

Objective An experimental study for testing a simple robust algorithm on data derived from an electromagnetic radiation device that can detect small changes in the tissue/fluid ratio in a realistic head configuration. Methods Changes in the scattering parameters (S21) of an inductive coil resulting from injections of chicken blood in the 0–18 ml range into calf brain tissue in a human anatomical skull were measured over a 100–1,000 MHz frequency range. Results An algorithm that combines amplitude and phase results was found to detect changes in the tissue/fluid ratio with 90% accuracy. An algorithm that estimated the injected blood volume was found to have a 1–4 ml average error. This demonstrates the possibility of the inductive coil-based device to possess a practical ability to detect a change in the tissue/fluid ratio in the head. Significance This study is an important step towards the goal of building an inexpensive and safe device that can detect an early brain hemorrhagic stroke.

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