scholarly journals Characterization of dielectric properties of the enamel filled with carbon nanotubes for the frequency range of 50 Hz - 5 MHz

2013 ◽  
Vol 1 (2) ◽  
pp. 102-106 ◽  
Author(s):  
D. Edison Selvaraj
2013 ◽  
Vol 80 (12) ◽  
Author(s):  
Niels Haandbæk ◽  
Sebastian C. Bürgel ◽  
Flavio Heer ◽  
Andreas Hierlemann

AbstractThis article presents a novel microfluidic impedance cytometer enabling dielectric characterization of single cells at frequencies up to 500 MHz. The dielectric properties of cells at lower frequencies contain information about their size and membrane capacitance. The increased frequency range of the presented cytometer potentially allows for characterization of intracellular components, such as vacuoles or the cell nuclei. We demonstrate the overall capabilities of the cytometer through discrimination of polystyrene beads from Chinese hamster ovary (CHO) cells. The discrimination is based on the difference in dielectric properties at frequencies up to 500 MHz.


2011 ◽  
Vol 2011 (1) ◽  
pp. 000740-000746 ◽  
Author(s):  
Bradley Thrasher ◽  
Deepukumar Nair ◽  
James Parisi ◽  
Glenn Oliver ◽  
Michael A. Smith

Low Temperature Co-fired Ceramic (LTCC) material systems offer a highly versatile microwave and millimeter wave packaging platform. Extremely low microwave loss, excellent control of dielectric constant, uniform dielectric thickness, non-existent water absorption leading to very high hermeticity, ability to support multilayer structure leading to 3-dimensional packaging, ability to embed passive functions within the tape layers, availability of a wide range of metallizations, etc. are some of the key advantages of LTCC for microwave packaging. One of the important parameters which needs to be determined at the very early stages of circuit designs are the dielectric properties - dielectric constant and loss tangent, both of which are functions of frequency. These properties need to be known accurately over the entire frequency range of operation for the circuit. For LTCC based designs, the use of dielectric constant of bulk material can lead to deviations between the performance expected at the design stage and for the fabricated circuit. Such deviations are a significant concern for broadband circuits as well as for circuits with sharp resonant behavior such as filters. One of the significant sources of deviation between bulk LTCC and “in-circuit” dielectric constant is the nature of the thick film metallizations used in LTCC technology. Work described here is a comprehensive characterization of three DuPont™ GreenTape™ LTCC systems 951, 943, and 9K7 - in the frequency range 10 to 70 GHz. Both bulk and “in-circuit” dielectric properties with silver and gold metallizations are studied to quantify the deviations in dielectric properties. A Fabry-Perot open resonator technique is used for the bulk characterization while printed ring resonators are used for the in-circuit characterization. This comprehensive characterization will provide key design data for LTCC designers in the 10 – 70 GHz frequency range.


Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 551-558
Author(s):  
S. Gümüştas ◽  
K. Köseoğlu ◽  
E. E. Yalçinkaya ◽  
M. Balcan

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.


1992 ◽  
Vol 269 ◽  
Author(s):  
Octavio M. Andrade ◽  
Magdy F. Iskander ◽  
Shane Bringhurst

ABSTRACTThis paper discusses theoretical and practical aspects of the development and implementation of various measurement techniques for high-temperature broadband microwave characterization of materials at the University of Utah. Objectives include materials measurements in the frequency range from 45 MHz to 12 GHz and for temperatures as high as 1000°C.


2008 ◽  
Vol 368-372 ◽  
pp. 123-125
Author(s):  
Jie Li ◽  
Hao Xue ◽  
Zhao Xian Xiong

CaCu3Ti4O12 (CCTO) ceramics were prepared by cold isostatic press (CIP) forming combined with the conventional sintering method. The effects of calcining temperature on properties of CCTO ceramics were investigated. The dielectric properties as the function of temperature at typical frequencies were measured in the temperature range from 243 to 363 K. In addition, the dielectric properties and complex impedances at room temperature were analyzed in a frequency range from 20 Hz to 106 Hz. The results showed that CCTO ceramics with dielectric constant higher than 104 were obtained. Compared with the dry press forming, CCTO ceramics prepared by CIP had more homogeneous grains, less porosity and better dielectric properties.


2017 ◽  
Vol 07 (01) ◽  
pp. 1720001 ◽  
Author(s):  
Jinwu Chen ◽  
Chunchun Li ◽  
Dan Wang ◽  
Huaicheng Xiang ◽  
Liang Fang

Single phase Li2W2O7 with anorthic structure was prepared by the conventional solid-state reaction method at 550[Formula: see text]C and the anorthic structure was stable up to 660[Formula: see text]C. The dielectric properties at radio frequency (RF) and microwave frequency range were characterized. The sample sintered at 640[Formula: see text]C exhibited the optimum microwave dielectric properties with a relative permittivity of 12.2, a quality factor value of 17,700[Formula: see text]GHz (at 9.8[Formula: see text]GHz), and a temperature coefficient of the resonant frequency of [Formula: see text]232[Formula: see text]ppm/[Formula: see text]C as well as a high relative density [Formula: see text]94.1%. Chemical compatibility measurement indicated Li2W2O7 did not react with aluminum electrodes when sintered at 640[Formula: see text]C for 4[Formula: see text]h.


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