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Low Dielectric Loss (low + dielectric_loss)
Selected AbstractsA New Compound with Ultra Low Dielectric Loss at Microwave FrequenciesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2009Ching-Fang Tseng A new ultra low loss microwave dielectric ceramic, Mg(Sn0.05Ti0.95)O3 (MSnT), was found and investigated. The compounds were prepared by the conventional solid-state route, and sintered at 1360°,1480°C for 2,6 h. The investigations show that the MgTi2O5 secondary phase was observed. Moreover, the dielectric properties were correlated with the formation second phase. The excellent microwave dielectric properties of Q×f=322 000 (GHz), ,r=17.4, and ,f=,54 ppm/°C were obtained from the new MSnT ceramics sintered at 1390°C for 4 h. [source] Efficient oxidative coupling polymerization for synthesis of thermosetting poly(phenylene ether) copolymer with a low dielectric lossJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2008Jun Nunoshige A novel oxidative coupling polymerization using a water/toluene heterogeneous system for the synthesis of thermosetting Poly(phenylene ether) copolymer (Allyl-PPE) was developed. Allyl-PPE with a narrow molecular weight distribution and a low copper content was obtained in the presence of a Cu/TMEDA catalyst dissolved in water droplets. This method solved the problems during the synthesis of the Allyl-PPE with conventional Cu/pyridine catalysts. The resulting Allyl-PPE exhibited excellent dielectric properties (,, = 2.4, tan , = 0.002 at 10 GHz), and it will be useful for applications to high-speed and high-frequency printed circuit boards. [source] Improved Dielectric Properties of Bi1.5Zn1.0Nb1.5O7/(111)-Oriented Ba0.6Sr0.4TiO3 Bilayered Films for Tunable Microwave ApplicationsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2010Lihui Yang Bi1.5Zn1.0Nb1.5O7/(111)-oriented Ba0.6Sr0.4TiO3 [BZN/BST (111)] bilayered films (,500-nm-thick) have been prepared on Pt/TiOx/SiO2/Si substrates by RF-magnetron sputtering. Experimental results suggested that the BZN layer has played a positive role in improving the dielectric properties of the films. With the increased thickness of BZN, the dielectric loss was significantly lowered, accompanied with a tolerable reduction of tunability. The thickness effect was discussed with a series connection model of multilayered capacitors, and the calculated permittivity was obtained. At 400 kV/cm, moderate tunability of 50.55%, low dielectric loss of 0.0108, and the largest figure of merit of 46.8 can be achieved for BZN (50 nm)/BST(450 nm) bilayered films. [source] Giant Permittivity of a Bismuth Zinc Niobate,Silver CompositeJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2007Sumesh George Bismuth zinc niobate,Silver (BZN,Ag) composites were prepared by the solid-state ceramic route. The sintering temperature of BZN,Ag composites was lowered to 850°C/2 h. The structure and surface morphology of the composites were investigated using X-ray diffraction and optical microscope. The dielectric and conducting properties of the composites were systematically investigated with the volume fraction of silver in the frequency range from 1 KHz to 1 MHz. The dielectric constant of the composite increases with the silver content and is in good agreement with the power law below the percolation limit. Addition of 0.14 volume fraction of silver increases the dielectric constant of BZN+2 wt% B2O3 from 150 to 2350 at 1 MHz. However, 15 volume percentage of silver loading results in a large permittivity of (,r),105 with a low dielectric loss (tan ,,10,2) at 1 MHz. Subsequent increase in silver loading decreases the dielectric constant. The BZN,B2O3,Ag composite with large permittivity may find applications in electromechanical and tunable devices. [source] Effect of heat treatment on the electrical properties of lead zirconate titanate/poly (vinylidene fluoride) compositesPOLYMER INTERNATIONAL, Issue 6 2010Lijie Dong Abstract Ceramic/polymer composites are attracting increasing interest in materials research and practical applications due to the combination of excellent electric properties of piezoelectric ceramics and good flexibility of polymer matrices. In this case, the crystallization of the polymer has a significant effect on the electric properties of ceramic/polymer composites. Based on different heat treatment methods, the crystallization of poly(vinylidene fluoride) (PVDF) in composites of lead zirconate titanate (PZT) and PVDF can be controlled effectively. PZT/PVDF composites with various PVDF crystallizations exhibit distinctive dielectric and piezoelectric properties. When the crystallization of PVDF is 21%, the PZT/PVDF composites show a high dielectric constant (,) of 165 and a low dielectric loss (tan ,) of 0.03 at 103 Hz, and when the crystallization of PVDF reaches 34%, the piezoelectric coefficient (d33) of PZT/PVDF composites can be up to ca 100 pC N,1. By controlling the crystallization of PVDF, PZT/PVDF composites with excellent dielectric and piezoelectric properties were obtained, which can be employed as promising candidates in high-efficiency capacitors and as novel piezoelectric materials. Copyright © 2010 Society of Chemical Industry [source] | ||||||||||