scholarly journals Cobalt Alumino Silicate Ceramic(CASC) nanocomposite, a material with moderately high dielectric constant and low tangent loss at a critical concentration in high frequency range.

2015 ◽  
Author(s):  
Sukhen Das ◽  
Biplab Paul ◽  
Smarajit Manna ◽  
Debasis Roy ◽  
Papiya Nandy
RSC Advances ◽  
2015 ◽  
Vol 5 (19) ◽  
pp. 14768-14779 ◽  
Author(s):  
K. Santhosh Kumar ◽  
Suresh Pittala ◽  
Srinath Sanyadanam ◽  
Pradip Paik

In this study, we introduce a single/few-layered graphene oxide (GO) synthesized with ultrasonication, and demonstrate its high dielectric permittivity in the frequency range of 20 Hz to 2 MHz and temperature range of 30 °C to 180 °C.


2010 ◽  
Vol 2010 (1) ◽  
pp. 000072-000075 ◽  
Author(s):  
Jin-Hyun Hwang ◽  
John Andresakis ◽  
Bob Carter ◽  
Yuji Kageyama ◽  
Fujio Kuwako

New and novel organic-based composite materials for the use of embedded RF capacitors have been developed to address the important material issues by means of functional filler and resin chemistry. Combining different fillers with appropriate chemistries, the net composite can be made thermally stable while retaining the high dielectric constant and low loss. These composites attained dielectric constant of above 7 without compromising the quality factor in GHz frequency range. In addition, measurement of capacitance variation as a function of temperature (TCC) showed flatter TCC profile, resulting in TCC of ±30 ppm/°C over the temperature range −55°C to 125°C. It can be incorporated into organic chip package and, unlike ceramic-based LTCC they can utilize large area processing that is typical, and available in high volume manufacturing. This material is formulated for RF module designers to successfully implement embedded RF capacitors into their organic chip package designs and thus improve form factor, electrical performance and possibly reduce overall costs.


2015 ◽  
Vol 815 ◽  
pp. 611-615 ◽  
Author(s):  
Qing Hou ◽  
Run Hua Fan ◽  
Zi Dong Zhang ◽  
Ke Lan Yan ◽  
Chuan Bing Cheng ◽  
...  

The microstructure and dielectric properties of the graphene–epoxy composites prepared by cryomilling at liquid nitrogen temperature were studied by SEM and RF impedance material analyzer. The result indicated that both the dielectric constant and conductivity of the composites increased with the increase of the graphene content. The value of the dielectric constant of the composite with about 8 wt % of graphene was as high as 200. Moreover, the frequency dispersion behaviors of the conductivity within a certain frequency range accorded with the Jonscher's power law demonstrating that the conductive mechanism is hopping conduction. The negative reactance decreased with the increase of the testing frequency which indicated a capacitive character


2017 ◽  
Vol 888 ◽  
pp. 7-11
Author(s):  
Rosyaini Afindi Zaman ◽  
Mohamad Johari Abu ◽  
Mohd Fariz Ab Rahman ◽  
Wan Fahmin Faiz Wan Ali ◽  
Julie Juliewatty Mohamed ◽  
...  

The dielectric properties of CCTO with addition Al2O3 prepared via solid state reaction investigated and reported at 1 GHz. With addition Al2O3 from 20 wt% to 80 wt%, secondary phase starts appear in XRD analysis such as copper dialuminium oxide (CuAl2O4), calcium titanate (CaTiO3) and titanium oxide (TiO2). These secondary phases show great influence on morphology and grain size of Al2O3/ CCTO composites. Hence, the addition of only 20 wt% Al2O3, the dielectric constant of CCTO reduce almost 50% and tangent loss is in between 0.0028 to 0.0630 which is very low and this characterization is suitable to use in electronic application in high frequency range.


2017 ◽  
Vol 6 (1) ◽  
pp. 76-79
Author(s):  
B. Chakradhar Sridhar ◽  
M. V. N. Ambika Prasad

The conducting Polyaniline/Vanadium Pentoxide (PANI/V2O5) composites were synthesized by single step in situ polymerization technique with 10, 20, 30, 40 and 50 wt% of V2O5 in polyaniline. The composites thus formed were characterized by Fourier infrared spectroscopy (FTIR), which confirmed the presence of V2O5 in polyaniline matrix and the formation of the composite. The AC conductivity has been studied in the frequency range of 50 Hz to 1 MHz and it is found that 40 wt% shows high conductivity compare to pure polyaniline and other composites. The high dielectric constant, which is related to polarization. It is seen that both dielectric constant and dielectric loss decrease with increase in frequency. The variation of impedance as a function of frequency suggesting nearly Debye-type relaxation mechanism. The results obtained for these composites are of scientific and technological interest.


2015 ◽  
Vol 1087 ◽  
pp. 246-250
Author(s):  
C.T. Ping ◽  
Sharifah Aishah Syed Salim ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad

NiO-based ceramic has shown high dielectric constant with 103-105, as well as high dielectric loss. Previous studies showed that doping with monovalent cations can cause a considerable decrease in dielectric loss. In this research, the effect of Lithium carbonate (Li2CO3) dopant on NiO was investigated. The electroceramic of LixNi1-xO were prepared by using solid state reaction method. The mixture of Li+ and NiO were ball milled for 24 hours. The samples were calcined at 800oC for 6 hours, pressed into pellet shape at 750 MPa and sintered at 1200°C for 10 hours. The sintered pellets were subjected to XRD, SEM, density testing and Impedance analyzer. XRD result shows the single phase formation of LixNi1-xO. The grain becomes larger with the increament of Li+ mole %. The dielectric constant of LixNi1-xO decrease with the increasing frequency. The highest dielectric constant was observed in x= 0.03 with 5210 at frequency range of 1GHz to 1MHz.


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