Positive microwave dielectric constant of metallic one-dimensional conductors

In the present work, the microstructure and microwave dielectric properties of BaTi4O9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (εr), quality factor (Q×f) and the temperature coefficients (τf) of the BaTi4O9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti3+ was proposed to be the cause of dielectric loss.

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Effect of Sintering Behavior on Microwave Properties of (Ca0.8Sr0.2)ZrO3 Ceramics for Resonators

Materials Science Forum ◽

10.4028/www.scientific.net/msf.787.338 ◽

2014 ◽

Vol 787 ◽

pp. 338-341

Author(s):

Cheng Hsing Hsu ◽

Chia Hao Chang ◽

Wen Shiush Chen ◽

Jenn Sen Lin ◽

Chun Hung Lai

Keyword(s):

Dielectric Constant ◽

Sintering Temperature ◽

Microwave Dielectric Properties ◽

Sintering Behavior ◽

Passive Components ◽

Suitable Candidate ◽

Solid State Route ◽

Microwave Dielectric ◽

Microwave Ceramic ◽

Conventional Solid State Route

Microwave dielectric properties and microstructures of (Ca0.8Sr0.2)ZrO3 ceramics prepared by the conventional solid-state route have been studied. The values of the dielectric constant (εr) were 22-26. The Q×f values of 10400–11500 GHz were obtained when the sintering temperatures were in the range of 1400–1490°C. The temperature coefficient of the resonant frequency τf was not sensitive to the sintering temperature. The εr value of 26, the Q×f value of 11500 GHz, and the τf value of-9 ppm/°C were obtained for (Ca0.8Sr0.2)ZrO3 ceramics sintering at 1490°C. The ceramic, (Ca0.8Sr0.2)ZrO3 is proposed as a suitable candidate material for application in highly selective microwave ceramic passive components.

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Estimation of Microwave Dielectric Constant Using Artificial Neural Networks

Advances in Intelligent Systems and Computing - Emerging Trends in Expert Applications and Security ◽

10.1007/978-981-13-2285-3_5 ◽

2018 ◽

pp. 41-46 ◽

Cited By ~ 1

Author(s):

K. Sujatha ◽

R. S. Ponmagal ◽

G. Saravanan ◽

Nallamilli P. G. Bhavani

Keyword(s):

Neural Networks ◽

Dielectric Constant ◽

Artificial Neural Networks ◽

Microwave Dielectric ◽

Artificial Neural

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Effect of Cu-Excess on the Microstructure and Microwave Dielectric Properties of CaCu3Ti4O12 Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1087.50 ◽

2015 ◽

Vol 1087 ◽

pp. 50-54 ◽

Cited By ~ 2

Author(s):

Mohamad Johari Abu ◽

Julie Juliewatty Mohamed ◽

Mohd Fadzil Ain ◽

Zainal Arifin Ahmad

Keyword(s):

Dielectric Constant ◽

Microwave Dielectric Properties ◽

Secondary Phase ◽

Solid State Reaction Method ◽

Lattice Parameter ◽

Tangent Loss ◽

Conventional Solid State Reaction ◽

Microwave Dielectric ◽

Order Of Magnitude ◽

Grain Growth Behavior

CaCu(3+x)Ti4O12 (CCTO) ceramics with different Cu-excess (x = 0 – 0.6) were prepared by conventional solid-state reaction method. Characterization of the prepared ceramics with XRD and FESEM showed that lattice parameter and grain size are slightly increased, indicating Cu-excess to have the big impact on the both phase structure and microstructure. The XRD profiles indicated that the secondary phase (CuO or Cu2O) existed at edge/corner of CCTO grain, which promoted inhibited grain growth behavior. The CCTO ceramics exhibited two trends of dielectric constant related to frequency, which showed a flatter curve about ~50 in 1 – 25 GHz regions, and it’s dropped rapidly to ~35 in 25 – 50 GHz region. With Cu-excess, the dielectric constant of the ceramics was increased for an average of a quarter-order of magnitude, while the tangent loss also increased up to triple times than x = 0, for the same frequency range. Despite enormous increase of dielectric constant related to varying Cu-excess, the tangent loss also increased.

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