The prediction of loss tangent of sewed multilayer fabric

2021 ◽  
pp. 004051752110642
Author(s):  
Yaya Zhang ◽  
Jiyong Hu ◽  
Xiong Yan ◽  
Huating Tu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
High Loss ◽  
Wearable Antennas ◽  
Low Dielectric ◽  
Equivalent Capacitance ◽  
Dielectric Constant And Loss ◽  
Proposed Model ◽  
The Relationship

The thickness and dielectric properties (dielectric constant and loss tangent) of fabric substrate play a key role in the design and properties of wearable antennas. Related research shows that a thicker substrate with a low dielectric constant and high loss tangent can enhance the bandwidth of antennas. Here, sewing multiple fabrics together was a good way to increase the thickness while maintaining flexibility, but it is hard to control the dielectric properties because of the lack of the relationship between the dielectric properties and that of the components. Although previous works have established the equivalent capacitance model of sewed multilayer fabric, they cannot obtain its dielectric properties completely. In this work, based on the circuit model proposed by Chin and Lee, the equivalent capacitance and resistance models of sewed multilayer fabric were established to predict its loss tangent. The sewed multilayer fabrics were fabricated and measured by split post dielectric resonator at 1.11 GHz to validate the model. From the comparison of the predicted and measured loss tangents of sewed multilayer fabrics, it was found that the predicted loss tangents agreed well with the experimental results. It is believed that the proposed model is beneficial to the rapid and rational configuration of the components for multilayer fabric according to thickness and dielectric properties of the components, and will provide a theoretical basis for the design of multilayer flexible electronic substrate.

Synthesis and Characteristics of MgO Coated BST-Mg2TiO4 Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1180-1183
Author(s):  
Qian Qian Jia ◽  
Hui Ming Ji ◽  
Shan Liu ◽  
Xiao Lei Li ◽  
Zheng Guo Jin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Curie Temperature ◽  
Loss Tangent ◽  
Phase Shifters ◽  
Precipitation Method ◽  
Composite Ceramics ◽  
Low Dielectric ◽  
Dielectric Constant And Loss ◽  
Bst Ceramics

The (Ba, Sr)TiO3 (hereafter BST) ceramics are promising candidate for applying in tunable devices. MgO coated BST-Mg2TiO4 (BSTM-MT) composite ceramics were prepared to obtain the low dielectric constant, low dielectric loss, good dielectric constant temperature stability, and high tunability of BST ceramics. The Ba0.55Sr0.40Ca0.05TiO3 nanoparticles were coated with MgO using the precipitation method and then mixed with Mg2TiO4 powders to fabricate BSTM-MT composite ceramics. The morphologies, phases, elements, and dielectric properties of the sintered ceramics were investigated. The core-shell structure of BST powder wrapped with MgO was clearly observed from the TEM image. After sintered at 1100 °C for 2 h, the composite ceramics expressed dense microstructures from SEM images and two main phases BST and Mg2TiO4 were detected in the XRD patterns. The dielectric constant and loss tangent were both reduced after the coating. The reduced dielectric constant and loss tangent of BSTM-MT were 190, 0.0011 (2MHz), respectively. The ceramics exhibited the diffuse phase transition near the Curie temperature and the Curie temperature shifted from 10 °C to 5 °C after the coating. Since the continuous Ti-O bonds were disconnected with the MgO coating, the tunability was reduced to 15.14 % under a DC bias field of 1.1 kV/mm. The optimistic dielectric properties made it useful for the application of tunable capacitors and phase shifters.

Effect of Platinum Substitution on the Microstructures and Dielectric Relaxation of CaCu3Ti4O12 Ceramics

2013 ◽  
Vol 802 ◽  
pp. 134-138 ◽  
Author(s):  
Worawut Makcharoen
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
High Dielectric Constant ◽  
Ferroelectric Materials ◽  
X Ray Diffraction ◽  
High Loss ◽  
Internal Barrier Layer Capacitor ◽  
High Dielectric

The CaCu3Ti4O12(CCTO) has the advantage for the various applications especially for capacitive elements in microelectronic devices over the ferroelectric materials including BaTiO3. CCTO is a ceramic compound with a high dielectric constant but it has a high loss tangent at room temperature. In this work, the Influences of PtO2doping on the dielectric properties of CaCu3Ti4O12(CCTO) ceramics were investigate. The ceramics CCTO and PtO2doping CCTO were studied by X- ray diffraction, scanning electron microscopy. The dielectric properties have been measured as a function of temperature and frequency range 0.1 - 500 kHz. The XRD shows the CCTO structure does not changes after doping with platinum. The results show that PtO2doped can reduce the mean grain sizes of CCTO, but the dielectric constant still remained a height. The samples of 2.0 mol% Pt-doped have exhibited high dielectric constant of about 22,000 and the loss tangent about 0.7 at room temperature and frequency at 10 kHz. The reduced of the loss tangent could be interpreted with the internal barrier layer capacitor model (IBLC)

Study of ferroelectric lead monohydrogen phosphate type crystals

2017 ◽  
Vol 31 (32) ◽  
pp. 1750260 ◽  
Author(s):  
Aanchal Rawat ◽  
Trilok Chandra Upadhyay
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Function Method ◽  
Mode Frequency ◽  
Temperature Variations ◽  
Ferroelectric Transition ◽  
Coupled Mode ◽  
Dielectric Constant And Loss

In this paper, the ferroelectric transition and dielectric properties of the lead monohydrogen phosphate (PbHPO4) crystal are theoretically investigated. By using Green’s function method and modified two sublattice pseudospin–lattice coupled mode model, formulae for PbHPO4 type crystals are derived. Temperature variations of ferroelectric mode frequency, dielectric constant and loss tangent are calculated for the PbHPO4 crystal. Our results agree well with the experimental data.

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.

Off Axis Growth of Strontium Titanate Films with High Dielectric Constant Tuning and Low Loss

2002 ◽  
Vol 720 ◽  
Author(s):  
Satreerat Kampangkeaw ◽  
Charles T. Rogers
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Strontium Titanate ◽  
Loss Tangent ◽  
Figure Of Merit ◽  
High Dielectric Constant ◽  
Dielectric Films ◽  
Low Loss ◽  
Dielectric Constant And Loss ◽  
High Dielectric

AbstractWe have measured the nonlinear dielectric properties of strontium titanate (STO) thin films grown on neodymium gallate (NGO) and lanthanum aluminate (LAO) substrates. The films prepared by off-axis pulsed laser deposition were characterized by their dielectric constant and loss tangent at 1 MHz and 2 GHz, and from room temperature down to 4 K. The resulting films show significant variations of dielectric properties with position of the substrates with respect to the plume axis. STO films on LAO substrates show low loss and high dielectric constant in regions near the plume axis. On the other hand, STO on NGO shows this effect only on the films grown far from the plume axis. We also obtained a figure of merit from the relative variation of the dielectric constant divided by the loss tangent in the presence of a DC electric field up to +/- 4 V/μm. Careful mapping of the plume crossection allowed us to improve the quality and reproducibility of the dielectric films, obtaining a best figure of merit at 2 GHz and 4 K close to 100 for NGO substrate but only well off axis.

Effect of Pb Volatilization on Dielectric Properties of 0.77PbMg1/3(Nb0.9Ta0.1)2/3O3-0.23PbTiO3

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3738-3744 ◽  
Author(s):  
C. Zhang ◽  
J. T. Wang ◽  
M. Q. Qian ◽  
T. P. Chen ◽  
I. Akujobi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Lead Magnesium Niobate ◽  
X Ray Diffraction ◽  
Low Dielectric ◽  
Dielectric Constant And Loss ◽  
Different Temperatures ◽  
Lead Magnesium ◽  
High Dielectric ◽  
The Cost

Lead magnesium niobate-lead titanate (PMN-PT) is an intriguing candidate for applications in many electronic devices such as multi-layer capacitors, electro-mechanical transducers etc. because of its high dielectric constant, low dielectric loss and high strain near the Curie temperature. As an extension of our previous work on Ta-doped PMNT-PT aimed at optimizing the performance and reducing the cost, this paper focuses on the effect of Pb volatilization on the dielectric properties of 0.77 Pb ( Mg 1/3( Nb 0.9 Ta 0.1)2/3) O 3-0.23 PbTiO 3. The dielectric constant and loss of the samples are measured at different frequencies and different temperatures. The phase purity of this compound is determined by X-ray diffraction pattern. It is found that the volatilization during sintering does influence the phase formation and dielectric properties. The best condition is sintering with 0.5 g extra PbO around a 4 g PMNT-PT sample.

Measurement of the Dielectric Constant and Loss Tangent of Polyester / Walnut Shells by the Cavity Perturbation Method at the Microwave X-band Frequencies

2021 ◽  
Vol 19 (3) ◽  
pp. 26-31
Author(s):  
Ahmed R. Mathloom
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Perturbation Method ◽  
Loss Tangent ◽  
Dominant Mode ◽  
Walnut Shells ◽  
Microwave Engineering ◽  
Dielectric Constant And Loss ◽  
X Band ◽  
Cavity Perturbation

In this paper, the cavity perturbation method was used to measure the dielectric properties of materials that are important for understanding the response to microwave waves, in terms of the ability of these materials to store energy and dissipate it as heat, respectively. Compounds (polyester / walnut shells) were prepared, and for different weight concentrations of walnut shells (WS) additive, the proportions ranged between (0% - 25%). The used cavity is rectangular in shape with a theoretically resonance frequency of around (9.9978 GHz) and exiting the dominant mode (TE101). The study shows the highest values of each dielectric constant with a weight concentration (25%) of the walnut shells, and the loss tangent without any material change to the sample. These compounds have been found to be useful in applications of electromagnetic materials such as microwave engineering and protection from biological influences when exposed to the field of microwaves, which is why it is very important to test their dielectric properties.

Dielectric Constant and Loss Tangent Characterization of Thin High-K Dielectrics Using Corner-to-Corner Plane Probing

2006 ◽  
Author(s):  
A. Ege Engin ◽  
Abdemanaf Tambawala ◽  
Madhavan Swaminathan ◽  
Swapan Bhattacharya ◽  
Pranabes Pramanik ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Loss Tangent ◽  
Dielectric Constant And Loss ◽  
High K

Novel soluble polyimides containing pyridine and fluorinated units: preparation, characterization, and optical and dielectric properties

RSC Advances ◽  
2016 ◽  
Vol 6 (26) ◽  
pp. 21662-21671 ◽  
Author(s):  
Weibing Dong ◽  
Yue Guan ◽  
Dejing Shang
Keyword(s):  
Dielectric Constant ◽  
Thermal Properties ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
Mechanical And Thermal Properties ◽  
Polyimide Films ◽  
Low Dielectric

To acquire low dielectric constant polyimide films with good mechanical and thermal properties and low CTE applied in microelectronic fields, three novel polyimides containing pyridine and –C(CF3)2– groups were firstly designed and synthesized.

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