Use of a Dielectric Glass to Join Dielectric Ceramics for Microwave Filters

2013 ◽  
Vol 787 ◽  
pp. 316-321 ◽  
Author(s):  
Xi Geng Miao ◽  
Fabrizia Ghezzo ◽  
Jing Jing Liu ◽  
Zhi Ya Zhao ◽  
Ruo Peng Liu
Keyword(s):  
Dielectric Loss ◽  
Microwave Filters ◽  
Environmental Stability ◽  
Bonding Layer ◽  
Dielectric Ceramic ◽  
Mixed Powder ◽  
Low Dielectric ◽  
Thermal Expansion Coefficients ◽  
Ceramic Components ◽  
Dielectric Glass

Joining of ceramics with glasses has been widely used for artificial teeth, solid oxide fuel cells, electrical devices, high temperature ceramic filters, structural ceramic components for aeronautic engineering, nuclear reactors, and other applications. This study aimed to explore the possibility of using a dielectric glass to connect a dielectric ceramic resonator to a dielectric ceramic support, in order to make miniaturized microwave filters characterized by higher temperature and environmental stability and low dielectric loss. A mixed powder having Bi2O3-SiO2-Al2O3-MgO-ZnO-CaO glass as a matrix and SiO2-Al2O3-MgO as a ceramic filler was used to join the dielectric ceramic resonators made of the CaTiO3-NdAlO3-Al2O3 system to the dielectric ceramic supports made of the ZnO-TiO2-Al2O3-MgO system. In spite of the strong interfacial bonding obtained, microcracks were observed in the joined bodies, suggesting that not only the dielectric loss of the bonding layer but also the match of the thermal expansion coefficients of the components to be joined should be carefully considered and tailored.

Temperature stable microwave dielectric ceramic 0.3Li2TiO3–0.7Li(Zn0.5Ti1.5)O4 with ultra-low dielectric loss

2011 ◽  
Vol 65 (17-18) ◽  
pp. 2680-2682 ◽  
Author(s):  
Ying Wu ◽  
Di Zhou ◽  
Jing Guo ◽  
Li-Xia Pang ◽  
Hong Wang ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Microwave Dielectric Ceramic ◽  
Dielectric Ceramic ◽  
Low Dielectric ◽  
Microwave Dielectric

Novel Low-Firing Microwave Dielectric Ceramic LiCa3 MgV3 O12 with Low Dielectric Loss

2013 ◽  
Vol 96 (3) ◽  
pp. 688-690 ◽  
Author(s):  
Liang Fang ◽  
Congxue Su ◽  
Huanfu Zhou ◽  
Zhenhai Wei ◽  
Hui Zhang
Keyword(s):  
Dielectric Loss ◽  
Microwave Dielectric Ceramic ◽  
Dielectric Ceramic ◽  
Low Dielectric ◽  
Microwave Dielectric

Brief Introduction of Microwave Ceramics Developed in our Labs for Dielectric Resonators

2014 ◽  
Vol 887-888 ◽  
pp. 294-298
Author(s):  
Xi Geng Miao ◽  
Jing Jing Liu ◽  
Fabrizia Ghezzo ◽  
Xiao Wei Fang ◽  
Zhi Ya Zhao ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Microwave Filters ◽  
Low Dielectric Constant ◽  
Sintering Aids ◽  
Microwave Ceramics ◽  
Dielectric Ceramic ◽  
Low Dielectric ◽  
Dielectric Ceramics ◽  
Frequency Temperature

Microwave filters require dielectric ceramic resonators attached to ceramic supports via joining. Among the BaTiO3, CaTiO3, and Ba2Ti9O20based-dielectric ceramics prepared in our labs., the CaTiO3ceramics modified with NdAlO3and Al2O3gave satisfactory dielectric properties: dielectric constant DK = 40.69, quality factor Qxf = 18842 GHz (fo = 6.551 GHz), and frequency temperature coefficient tf= 2.542 ppm °C-1. For replacing the hard-to-sinter Al2O3based-ceramic supports, a glass-ceramic of the SiO2-B2O3-P2O5-ZnO system was developed, leading to a low sintering temperature of 900 °C, and a low dielectric constant (<4). Finally, a Bi2O3-ZnO-SiO2-Al2O3-CaO glass was used as a sealing agent to replace the traditional gluing consisting of an adhesive. The present work hinters that with proper sintering aids, one can produce multilayered and integrated resonators with and without embedded passive elements.

Skin–core structured fluorinated MWCNTs: a nanofiller towards a broadband dielectric material with a high dielectric constant and low dielectric loss

2018 ◽  
Vol 6 (9) ◽  
pp. 2370-2378 ◽  
Author(s):  
Yang Liu ◽  
Cheng Zhang ◽  
Benyuan Huang ◽  
Xu Wang ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Epoxy Composite ◽  
Low Dielectric ◽  
High Dielectric

A novel skin–core structured fluorinated MWCNT nanofiller was prepared to fabricate epoxy composite with broadband high dielectric constant and low dielectric loss.

Magnetodielectric Ni ferrite ceramics with Bi2O3 additive for potential antenna miniaturizations

2009 ◽  
Vol 24 (2) ◽  
pp. 324-332 ◽  
Author(s):  
X.T. Liew ◽  
K.C. Chan ◽  
L.B. Kong
Keyword(s):  
Magnetic Properties ◽  
Dielectric Loss ◽  
Grain Growth ◽  
Sintering Temperature ◽  
Magnetic Loss ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
Low Dielectric ◽  
High Concentrations

This paper reports on the preparation and characterization of nickel ferrite (NiFe1.98O4) ceramics doped with Bi2O3 as sintering aid. Focus has been on the effects of concentration of Bi2O3 and sintering temperature on the densification, grain growth, dielectric, and magnetic properties of the NiFe1.98O4 ceramics, with an aim at developing magnetodielectric properties, with almost equal real permeability and permittivity, as well as sufficiently low magnetic and dielectric loss tangents, over 3 to 30 MHz (high frequency or HF band). X-ray diffraction results indicated that there is no obvious reaction between NiFe1.98O4 and Bi2O3, at Bi2O3 levels of up to 7 wt% and temperatures up to 1150 °C. The addition of Bi2O3 facilitated a liquid phase sintering mechanism for the densification of NiFe1.98O4 ceramics. The addition of Bi2O3 not only improved the densification but also promoted the grain growth of NiFe1.98O4 ceramics. To achieve sufficiently low dielectric loss tangent, the concentration of Bi2O3 should not be less than 5 wt%. The low dielectric loss tangents of the samples doped with high concentrations of Bi2O3 can be attributed to the full densification of the ceramics. Magnetic properties of the NiFe1.98O4 ceramics, as a function of sintering temperature and Bi2O3 concentration, can be qualitatively explained by the Globus model. Promising magnetodielectric properties have been obtained in the sample doped with 5% Bi2O3 and sintered at 1050 °C for 2 h. The sample has almost equal values of permeability and permittivity of ∼12, together with low dielectric and magnetic loss tangents, over 3 to 30 MHz. This material might be useful for the miniaturization of HF (3 to 30 MHz) antennas.

scholarly journals Crown ether-containing polyimides with high dielectric constant

RSC Advances ◽  
2017 ◽  
Vol 7 (38) ◽  
pp. 23309-23312 ◽  
Author(s):  
Ting Yang ◽  
Wenhui Xu ◽  
Xinwen Peng ◽  
Haoqing Hou
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Crown Ether ◽  
High Dielectric Constant ◽  
Low Dielectric ◽  
High Dielectric

Crown ether-containing polyimides possess high dielectric constant and low dielectric loss, without sacrificing other properties.

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.

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