Origin of the High-Frequency Contributions to the Dielectric Loss in Supercooled Liquids

2002 ◽  
Vol 89 (2) ◽  
Author(s):  
S. Hensel-Bielowka ◽  
M. Paluch
Keyword(s):  
Dielectric Loss ◽  
High Frequency ◽  
Supercooled Liquids

High Frequency Dielectric Response of the Ionic Liquid N-Methyl-N-ethylpyrrolidinium Dicyanamide

2007 ◽  
Vol 60 (1) ◽  
pp. 6 ◽  
Author(s):  
Simon Schrödle ◽  
Gary Annat ◽  
Douglas R. MacFarlane ◽  
Maria Forsyth ◽  
Richard Buchner ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
High Frequency ◽  
Dielectric Response ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range ◽  
Fast Rotation

A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.

scholarly journals Core-Shell Sr2CeO4@SiO2 Filled COC‑Based Composites with Low Dielectric Loss for High-Frequency Substrates

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4006
Author(s):  
Qinlong Wang ◽  
Hao Wang ◽  
Caixia Zhang ◽  
Qilong Zhang ◽  
Hui Yang
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Loss ◽  
High Frequency ◽  
High Speed ◽  
Heat Dissipation ◽  
Coefficient Of Thermal Expansion ◽  
Signal Transmission ◽  
Sol Gel ◽  
Normal Operation ◽  
Core Shell

High-frequency communication equipment urgently needs substrate materials with lower dielectric loss, better heat dissipation, and higher stability, to ensure real-time low-loss and high-speed signal transmission. The core-shell structure of Sr2CeO4@SiO2 was prepared by the sol-gel method, and the modified powders with different volume contents were introduced into the cyclic olefin copolymer (COC) to prepare hydrocarbon resin-based composites. Due to the protective effect of the SiO2 shell, the stability of the powders is significantly improved, and the moisture barrier and corrosion resistance of the composites are enhanced, which is conducive to the normal operation of electronic equipment in harsh and complex environments. When the filler content is 20 vol%, the composite has a dielectric loss of 0.0023 at 10 GHz, a dielectric constant of 3.5, a thermal conductivity of 0.9 W·m−1·K−1, a water absorption of 0.32% and a coefficient of thermal expansion of 37.7 ppm/℃. The COC/Sr2CeO4@SiO2 composites exhibit excellent dielectric properties and thermal conductivity, while maintaining good moisture resistance and dimensional stability, which shows potential application prospects in the field of high-frequency substrates.

Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro- und Submillimeter-Wellen. I. Primäre Amine / Intramolecular Dipole Reorientation and Dielectric Loss of Microwaves and, Submillimetrewaves in Diluted Solution I. Primary Amines

1982 ◽  
Vol 37 (2) ◽  
pp. 102-112
Author(s):  
G. Klages ◽  
E. Wieczorek
Keyword(s):  
Dipole Moment ◽  
Dielectric Loss ◽  
High Frequency ◽  
Aliphatic Amines ◽  
Primary Amines ◽  
High Frequency Region ◽  
Debye Relaxation ◽  
Diluted Solution ◽  
Wave Region ◽  
Molecular Resonances

Abstract The dielectric loss of very diluted solutions of four aromatic and three aliphatic amines in three non polar aliphatic solvents at 20 °C has been measured. The wave numbers cover 0.1 to 200 cm-1 . It is shown, how to analyse the microwave spectra of the loss factor ε″ in terms of three absorption areas, two of Debye relaxation type and the high frequency one of Lorentz resonance type. To limit the latter at its high frequency side, the extinction coefficient a has been used to determine and separate the lowest molecular resonances. From the analysis, dispersion steps and the components of the dipole moment due to the three absorption regions are calculated. Comparison with the so called optical dispersion step insures within the limits of experimental error that the absorption due to orientation of the permanent dipole moment is covered by the measured band. The long wave region belongs to the rotation of the molecules, the two others to intramolecular reorientation. In aromatic amines not all molecules of the sample are able to invert their NH2 group, but slower orientation by hindered inversion happens. On the other hand, in aliphatic amines the group is rotating and the high frequency region may be due to Foley absorption.

Photosensitive Polyimide having low loss tangent for RF application

2018 ◽  
Vol 2018 (1) ◽  
pp. 000476-000482 ◽  
Author(s):  
Masao Tomikawa ◽  
Hitoshi Araki ◽  
Yohei Kiuchi ◽  
Akira Shimada
Keyword(s):  
Molecular Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
High Frequency ◽  
Low Dielectric Constant ◽  
Low Loss ◽  
Elongation At Break ◽  
Low Dielectric ◽  
The Poor

Abstract Progress of 5G telecommunication and mm radar for autopilot, high frequency operation is required. Insulator materials having low loss at high frequency is desired for the applications. We designed the low dielectric constant, and low dielectric loss materials examined molecular structure of the polyimide and found that permittivity 2.6 at 20GHz, dielectric loss 0.002. Furthermore, in consideration of mechanical properties such as the toughness and adhesion to copper from a point of practical use. Dielectric properties largely turned worse when giving photosensitivity. To overcome the poor dielectric properties, we designed the photosensitive system. After all, we successfully obtained 3.5 of dielectric constant and 0.004 of dielectric loss, and 100% of elongation at break. In addition, we offered a B stage sheet as well as varnish. These materials are applicable to re-distribution layer of FO-WLP, Interposer and other RF applications for microelectronics.

scholarly journals MPPE/SEBS Composites with Low Dielectric Loss for High-Frequency Copper Clad Laminates Applications

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1875
Author(s):  
Jianming Guo ◽  
Hao Wang ◽  
Caixia Zhang ◽  
Qilong Zhang ◽  
Hui Yang
Keyword(s):  
Dielectric Loss ◽  
High Frequency ◽  
Composite Laminates ◽  
Printed Circuit Boards ◽  
Coefficient Of Thermal Expansion ◽  
Weight Ratio ◽  
Resin Matrix ◽  
Ceramic Powders ◽  
Low Dielectric ◽  
Low Dissipation

Copper clad laminates (CCLs) with low dissipation factor (Df) are urgently needed in the fields of high-frequency communications devices. A novel resin matrix of modified poly (2,6-dimethyl-1,4-phenylene ether) (MPPE) and styrene-ethylene/butylene-styrene (SEBS) was employed in the fabrication of high-frequency copper clad laminates (CCLs). The composites were reinforced by E-glass fabrics, which were modified with phenyltriethoxysilane (PhTES). The composite laminates obtained exhibited impressive dielectric loss of 0.0027 at 10 GHz when the weight ratio of MPPE to SEBS was 5:1. In order to modify the dielectric constant (Dk), coefficient of thermal expansion (CTE) and other performances of laminates, Li2TiO3 (LT) ceramic powders were introduced into the resin matrix. The composite laminates showed low dielectric loss of 0.0026 at 10 GHz and relatively high flexural strength of 125 MPa when the mass ratio of LT fillers to resin is 0.4. Moreover, the composite laminates all maintain low water uptake (<0.5%). The microstructure and thermal properties of composite laminates filled with LT ceramic powders were also tested. These results show that copper clad laminates prepared with modified polyphenylene ether (MPPE)/SEBS and LT ceramic fillers have strong competitiveness to fabricate printed circuit boards (PCBs) for high-frequency and high-speed applications.

Improved conductivity and reduced dielectric loss of Cu- substituted NiFe2O4 for high frequency applications

2020 ◽  
Vol 839 ◽  
pp. 155601 ◽  
Author(s):  
H. Chouaibi ◽  
J. Khelifi ◽  
A. Benali ◽  
E. Dhahri ◽  
M.A. Valente ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
High Frequency
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