Characterization of TC-3 Glass/Fused Silica Composites for LTCC Applications

2014 ◽  
Vol 492 ◽  
pp. 281-285 ◽  
Author(s):  
Xi Geng Miao ◽  
Xian Gao Zhang ◽  
Xiao Wei Fang ◽  
Fabrizia Ghezzo ◽  
Zhi Ya Zhao ◽  
...  
Keyword(s):  
Ceramic Composite ◽  
Tape Casting ◽  
Silica Particles ◽  
Fused Silica ◽  
Brand Name ◽  
Low Loss ◽  
Low Dielectric ◽  
Microwave Applications ◽  
Silver Palladium

A glass powder of the SiO2-Al2O3-K2O-Na2O system was added to fused silica particles to form composite green compacts by tape casting. This procedure was able to lower the sintering temperature of the fused silica particles making the composites suitable for being co-fired with the silver-palladium (Ag-Pd) paste commonly used as a conductive circuit in several microwave applications. The resulting new ceramic composite with the composition of 50 wt% fused silica and 50 wt% glass (brand name: TC-3) had a low dielectric constant and a low loss tangent of 2.7 and 2.5-3.7 x10-3 , respectively, and was able to be co-fired with the Ag-Pd conductive paste at the temperature of 895 °C, resulting in a potential low temperature co-fired ceramic (LTCC) system for microwave applications.

PREPARATION AND CHARACTERIZATION OF MECHANICALLY FLEXIBLE RUBBER-CERAMIC COMPOSITE DIELECTRICS

2013 ◽  
Vol 22 ◽  
pp. 148-152
Author(s):  
DHANESH THOMAS ◽  
M. T. SEBASTIAN
Keyword(s):  
Dielectric Loss ◽  
Hot Pressing ◽  
Relative Permittivity ◽  
Ceramic Composite ◽  
Temperature Stability ◽  
Theoretical Models ◽  
Butyl Rubber ◽  
Low Dielectric

Butyl rubber — Ca 4 La 6( SiO 4)4( PO 4)2 O 2 — composites have been prepared by sigma mixing and hot pressing. The relative permittivity of the composites varies from 3 to 5.3 at 1 MHz. All the composites show low dielectric loss of the order of 10−3 at 1 MHz. The experimentally observed values of relative permittivity are correlated with those calculated using various theoretical models. The composites show good temperature stability of relative permittivity.

scholarly journals Characterization of ejected fused silica particles following surface breakdown with nanosecond pulses

2012 ◽  
Vol 20 (25) ◽  
pp. 27708 ◽  
Author(s):  
Rajesh N. Raman ◽  
Selim Elhadj ◽  
Raluca A. Negres ◽  
Manyalibo J. Matthews ◽  
Michael D. Feit ◽  
...  
Keyword(s):  
Silica Particles ◽  
Fused Silica ◽  
Nanosecond Pulses ◽  
Surface Breakdown

scholarly journals Experimental Characterization of Sandwich Radome for Airborne Applications

2019 ◽  
Vol 9 (1) ◽  
pp. 1206-1212
Keyword(s):  
Mechanical Performance ◽  
Impact Load ◽  
Maximum Load ◽  
Face Sheet ◽  
Low Loss ◽  
High Mechanical Strength ◽  
Impact Simulation ◽  
Low Dielectric ◽  
Bird Impact

Radome is a structural weather proof enclosure that protects radar system from the environment. Radomes are manufactured using composite materials that have low dielectric constant and low loss tangent. The selected materials should have high mechanical strength to withstand aerodynamic and bird impact load conditions. Thus, the design of a radome is always a trade-off between electrical and structural requirements. In the present study, set of Uni-directional (UD) and Bi-directional (BD) glass fabric used as high density face sheet with low density foam ROHACELL 71 Hero grade and Nomex honeycomb as core materials are used to form sandwich radomes. These samples are tested for mechanical performance as per ASTM standards. The maximum load bearing capacity was found higher for the Nomex sandwich with UD face, by 27% than the Rohacell sandwich with UD Face sheet. Nomex sandwich with BD face sheet have higher compressive modulus among other three configurations. The bird impact simulation results show sandwich panel selected is capable of withstanding bird impact load at a velocity of 150 m/s. The measured antenna patterns with and without radome material for frequency range from 2.5 GHz to 4.5 GHz is also discussed.

Fabrication and characterization of anisotropic dielectrics for low-loss microwave applications

2008 ◽  
Vol 43 (5) ◽  
pp. 1505-1509 ◽  
Author(s):  
Lanlin Zhang ◽  
Gokhan Mumcu ◽  
Salih Yarga ◽  
Kubilay Sertel ◽  
John L. Volakis ◽  
...  
Keyword(s):  
Low Loss ◽  
Anisotropic Dielectrics ◽  
Microwave Applications ◽  
Fabrication And Characterization

Fused Silica Ceramics and Composites for Radome Applications

2014 ◽  
Vol 900 ◽  
pp. 123-129 ◽  
Author(s):  
Xi Geng Miao ◽  
Yu Rui Qu ◽  
Fabrizia Ghezzo ◽  
Xiao Wei Fang ◽  
Yu Tao Yue ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Frequency Selective Surface ◽  
Multilayered Structure ◽  
Transmission Efficiency ◽  
Fused Silica ◽  
Low Dielectric Constant ◽  
Dense Layer ◽  
Low Loss ◽  
Low Dielectric ◽  
Water Proof

The processing methods, strengthening methods, water-proof coating procedures, and some ways to improve the transmission of microwaves have been reviewed in relation to fused silica ceramics and their composites for radome applications. Fused silica ceramics are characterized by a residual porosity (up to 18%), low dielectric constant (3.06-3.32), low loss tangent (0.00053-0.0065), excellent thermal properties, but low mechanical strength (37-65 MPa). To achieve higher mechanical strength and better transmission efficiency, new randome materials would be those engineered composites consisting, for instance, of a dense layer-porous core structure, a continuous fiber reinforcement, a multilayered structure, and/or frequency selective surface (FSS) layer (s)/metamaterials.

scholarly journals Microstructure and Thermoelectric Properties of (Bi0.48Sb1.52)Te3 Thick Films Prepared with Tape Casting Method

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 140
Author(s):  
Lichen Liu ◽  
Ziping Cao ◽  
Min Chen ◽  
Jun Jiang
Keyword(s):  
Thermoelectric Properties ◽  
Low Cost ◽  
Thick Films ◽  
Tape Casting ◽  
Casting Process ◽  
Casting Method ◽  
Glass Substrates ◽  
Conductive Films ◽  
Casting Technology

This paper reports the fabrication and characterization of (Bi0.48Sb1.52)Te3 thick films using a tape casting process on glass substrates. A slurry of thermoelectric (Bi0.48Sb1.52)Te3 was developed and cured thick films were annealed in a vacuum chamber at 500–600 °C. The microstructure of these films was analyzed, and the Seebeck coefficient and electric conductivity were tested. It was found that the subsequent annealing process must be carefully designed to achieve good thermoelectric properties of these samples. Conductive films were obtained after annealing and led to acceptable thermoelectric performance. While the properties of these initial materials are not at the level of bulk materials, this work demonstrates that the low-cost tape casting technology is promising for fabricating thermoelectric modules for energy conversion.

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