scholarly journals Inorganic dopants in polymer cholesteric liquid crystals

2015 ◽  
Vol 34 (2) ◽  
pp. 381
Author(s):  
Anka Trajkovska
Keyword(s):  
Dielectric Constant ◽  
Low Cost ◽  
Cholesteric Liquid Crystal ◽  
Polymer Processing ◽  
Base Polymer ◽  
Energy Consuming ◽  
Optical Applications ◽  
High Dielectric ◽  
Logarithmic Equation ◽  
Polymer Cholesteric Liquid Crystals

<p>A variety of dopants are used for different types of polymers to change their properties. Inorganic dopants are usually used to change the dielectric properties of the polymers. These compositions find different applications especially in electronic systems due to ease of polymer processing, increased functionality and low cost of novel materials that are with relatively high dielectric constant compared to the base polymer material.</p><p>In this study, polymer cholesteric liquid crystal (PCLC) is used as a host material that is doped by different inorganic dopants, BaTiO<sub>3</sub> and TiO<sub>2</sub>, all of them affected the dielectric constant of the polymer matrix. This is important from the fact that doped PCLC can be used for a variety of electro-optical applications, e.g. display applications and low energy consuming e-book application. The behaviour of inorganic dopants in PCLC is calculated by various existing mixing models; the best fit is observed by use of logarithmic equation.</p>

Flexible and low cost lead free composites with high dielectric constant

2017 ◽  
Vol 43 (4) ◽  
pp. 3923-3926 ◽  
Author(s):  
Muhammad Nauman Khan ◽  
Nadeem Jelani ◽  
Chunchun Li ◽  
Jibran Khaliq
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Low Cost ◽  
Lead Free ◽  
High Dielectric

A Low-Cost Chemical Route for High Dielectric Constant Plate-Shaped Nanocrystalline CaCu3Ti4O12

2012 ◽  
Vol 16 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Ranjit Kumar ◽  
M. Zulfequar ◽  
V. N. Singh ◽  
Sukhvir Singh ◽  
T. D. Senguttuvan
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Low Cost ◽  
Chemical Route ◽  
High Dielectric

High performance dielectric composites by latex compounding of graphene oxide-encapsulated carbon nanosphere hybrids with XNBR

2014 ◽  
Vol 2 (29) ◽  
pp. 11144-11154 ◽  
Author(s):  
Ming Tian ◽  
Qin Ma ◽  
Xiaolin Li ◽  
Liqun Zhang ◽  
Toshio Nishi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Graphene Oxide ◽  
Elastic Modulus ◽  
High Performance ◽  
High Dielectric Constant ◽  
Low Cost ◽  
Low Dielectric ◽  
Low Elastic Modulus ◽  
High Dielectric ◽  
Latex Compounding

A novel dielectric composite with high dielectric constant (k), low dielectric loss, low elastic modulus and large actuated strain at a low electric field was prepared by a simple, low-cost and efficient method.

Photodefinable Metal Oxide Dielectrics: A Novel Method for Fabricating Low Cost RF Capacitive MEMS Switches

2003 ◽  
Vol 783 ◽  
Author(s):  
Guoan Wang ◽  
Augustin Jeyakumar ◽  
John Papapolymerou ◽  
Clifford L. Henderson
Keyword(s):  
Dielectric Constant ◽  
Metal Oxide ◽  
Rf Mems ◽  
High Dielectric Constant ◽  
Low Cost ◽  
Organic Precursor ◽  
Mems Switches ◽  
Novel Approach ◽  
Capacitive Mems ◽  
High Dielectric

ABSTRACTIn this paper, a novel approach for fabricating low cost capacitive RF MEMS switches using directly photodefinable high dielectric constant metal oxides has been developed. In this approach, a radiation sensitive metal-organic precursor is deposited via spin coating and converted patternwise to a high dielectric constant metal oxide via ultraviolet exposure. The feasibility of this approach is demonstrated by fabricating bridge-type and cantilever-type switches with a nitride/metal-oxide/nitride dielectric film stack. These switches exhibited significantly higher isolation and load capacitances as compared to comparable switches fabricated using a simple silicon nitride dielectric.

scholarly journals High dielectric constant of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3 prepared by the hydrothermal method

2019 ◽  
Vol 8 (3) ◽  
pp. 213-219
Author(s):  
Mohammed Mesrar ◽  
Tajdine Lamcharfi ◽  
Nor-Said Echatoui ◽  
Farid Abdi ◽  
Ahmed Harrach
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Low Cost ◽  
Low Frequency ◽  
Treatment Temperature ◽  
Synthesis Conditions ◽  
Heating Treatment ◽  
Alkaline Conditions ◽  
Preparation Route ◽  
High Dielectric

In this study, hydrothermal synthesis conditions for the formation of (1-x (Na0.5Bi0.5)TiO3-xBaTiO3  (x=0; 0.03; 0.05; 0.06; 0.07; 0.08 and 0.1)  compounds were investigated. The process parameters such as the alkaline conditions and heating treatment (temperature, time) as well the influence of the (Na, Bi)/Ba ratio were investigated in detail. The as-prepared NBT powders were characterized by X-ray powder diffraction, scanning electron microscope (SEM) and dielectric measurements. Taking into account NBT behavior draws consideration to phenomena of the ion ordering, coexistence of various phase regions in a crystal lattice, phase transition diffusion and a considerably new phenomenon: the existence of a very high dielectric constant at low frequency. Our result presents a simple preparation route for low-cost and high-purity.

Next Generation High Dk, Low Df Organic Laminate for RF Modules and High Frequency Applications

2010 ◽  
Vol 2010 (1) ◽  
pp. 000836-000841
Author(s):  
Fuhan Liu ◽  
Vivek Sridharan ◽  
Tapobrata Bandyopadhyay ◽  
Venky Sundaram ◽  
Rao Tummala ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Loss Tangent ◽  
Transmission Lines ◽  
High Frequency ◽  
High Performance ◽  
Smooth Surface ◽  
Low Cost ◽  
Propagation Loss ◽  
Hole Drilling ◽  
High Dielectric

In this paper, we present a novel high density high performance ultra-thin organic laminate, X-R-1, with low cost standard PCB fabrication processes for RF and high frequency applications. The X-R-1 substrate, developed at Zeon Corporation is a new generation halogen-free high dielectric constant (Dk) and low loss tangent (Df) dielectric laminate material. Its dielectric constant is 6.5–6.7 in the range of 1–20GHz, similar to typical LTCC substrates but larger than most organic materials such as LCP, PTFE and Epoxy based materials. Its dielectric loss tangent is 0.003, similar to that of LTCC, LCP and PTFE but much lower than epoxy based materials. The thicknesses of the core used in this study are 50um. The clad copper on both sides is a 12um thick profile-free copper foil which provides extremely smooth surface. Microminiaturization of RF devices can be achieved by the combination of high Dk and ultra-thin substrate. The combination of low Df and smooth surface leads to RF and high frequency signals having minimum propagation loss. The material is suitable for mechanical and laser through hole drilling and fully compatible with the low cost standard PCB facilities and processes. Because of the smooth surface, 25um very fine copper lines and spaces were achieved by wet etching process. Copper filled through holes with 40um diameter drilled by CO2 laser have been demonstrated. Panel size of 6″×6″ test vehicles with RF filters and transmission lines was fabricated and measured. Test data on the filters at 2.4GHz and 5GHz has been presented in this paper. This high Dk and low Df laminate with standard PCB processes provides a low cost organic platform for RF and high frequency circuit applications.

scholarly journals High dielectric constant of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3 prepared by the hydrothermal method

2019 ◽  
Vol 8 (3) ◽  
pp. 213
Author(s):  
Mohammed Mesrar ◽  
Tajdine Lamcharfi ◽  
Nor-Said Echatoui ◽  
Farid Abdi ◽  
Ahmed Harrach
Keyword(s):  
Dielectric Constant ◽  
High Dielectric Constant ◽  
Low Cost ◽  
Low Frequency ◽  
Treatment Temperature ◽  
Synthesis Conditions ◽  
Heating Treatment ◽  
Alkaline Conditions ◽  
Preparation Route ◽  
High Dielectric

<p>In this study, hydrothermal synthesis conditions for the formation of (1-x (Na<sub>0.5</sub>Bi<sub>0.5</sub>)TiO<sub>3</sub>-xBaTiO<sub>3</sub>  (x=0; 0.03; 0.05; 0.06; 0.07; 0.08 and 0.1)  compounds were investigated. The process parameters such as the alkaline conditions and heating treatment (temperature, time) as well the influence of the (Na, Bi)/Ba ratio were investigated in detail. The as-prepared NBT powders were characterized by X-ray powder diffraction, scanning electron microscope (SEM) and dielectric measurements. Taking into account NBT behavior draws consideration to phenomena of the ion ordering, coexistence of various phase regions in a crystal lattice, phase transition diffusion and a considerably new phenomenon: the existence of a very high dielectric constant at low frequency. Our result presents a simple preparation route for low-cost and high-purity.</p>

Microstructural characterization of YBaCuO Films on LaAlO3 substrates

1989 ◽  
Vol 47 ◽  
pp. 180-181
Author(s):  
E. L. Hall ◽  
A. Mogro-Campero ◽  
N. Lewis ◽  
L. G. Turner
Keyword(s):  
Dielectric Constant ◽  
Single Crystal ◽  
Film Growth ◽  
Microstructural Characterization ◽  
Lattice Parameter ◽  
Film Plane ◽  
Substrate Material ◽  
High Loss ◽  
Amorphous Substrates ◽  
High Dielectric

There have been a large number of recent studies of the growth of Y-Ba-Cu-O thin films, and these studies have employed a variety of substrates and growth techniques. To date, the highest values of Tc and Jc have been found for films grown by sputtering or coevaporation on single-crystal SrTiO3 substrates, which produces a uniaxially-aligned film with the YBa2Cu3Ox c-axis normal to the film plane. Multilayer growth of films on the same substrate produces a triaxially-aligned film (regions of the film have their c-axis parallel to each of the three substrate <100> directions) with lower values of Jc. Growth of films on a variety of other polycrystalline or amorphous substrates produces randomly-oriented polycrystalline films with low Jc. Although single-crystal SrTiO3 thus produces the best results, this substrate material has a number of undesireable characteristics relative to electronic applications, including very high dielectric constant and a high loss tangent at microwave frequencies. Recently, Simon et al. have shown that LaAlO3 could be used as a substrate for YBaCuO film growth. This substrate is essentially a cubic perovskite with a lattice parameter of 0.3792nm (it has a slight rhombohedral distortion at room temperature) and this material exhibits much lower dielectric constant and microwave loss tangents than SrTiO3. It is also interesting from a film growth standpoint since it has a slightly smaller lattice parameter than YBa2Cu3Ox (a=0.382nm, b=c/3=0.389nm), while SrTiO3 is slightly larger (a=0.3905nm).

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