Crystals
·
2022
·Vol. 12
·期 4
·512
·
IF 2.67
Zhijian Wang,Feng Pan,Lanlan Liu,Qifeng Du,Ruitao Tang,Jun Ai,Hong Zhang,Ying Chen
Mg2SiO4holds promise for its application in the microwave communication field due to its low dielectric constant and highQ×fvalue. However, its high negativeτfand high sintering temperature limit its application in low-temperature co-fired ceramic (LTCC) devices. In this work, Li2TiO3and CaTiO3were introduced to improve theτf, and LiF was chosen to decrease the sintering temperature. According to XRD patterns and SEM micrographs, the ceramic systems displayed a complex-phase structure, and the microstructure was densified when CaTiO3was added. All of the relative densities, dielectric constants, andQ×fvalues first increased and then decreased as the sintering temperature increased. The MLLC11.5 ceramics sintered at 800 °C could be obtained with the highestQ×fvalue of 54,581 GHz (at 8.06 GHz),εrof 14.13, andτfof + 5.81 ppm/°C. Furthermore, it was proven that the MLLC11.5 powders could be co-fired without any reaction with Ag powders at 800 °C, indicating its potential for LTCC application. The MLLC11.5 composition was used to prepare a GPS antenna and showed good prospects for its application in electronic communications.Keywords:Mg2SiO4-Li2TiO3-LiF-CaTiO3ceramics;structure;microwave dielectric property;LTCC;antenna
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
FERROELECTRICS
·
2017
·
IF 0.551
Shaolei Xie,Shuangbin Li,Jiang Xiao,Ying Yao,Yongzhong Jia
PbTiO3 and CaTiO3 ceramics are prepared at temperatures above 2000°C by a direct current arc discharge technique under an argon atmosphere, and the microstructure, components and morphology of each material are investigated. Both samples show the formation of a perovskite structure. Moreover, a tetragonal phase is found in the PbTiO3 ceramic material, and a cubical phase is formed in the CaTiO3 ceramic material. In this work, PbTiO3 and CaTiO3 ceramics were rapidly prepared using a simple DC arc discharge technique; we found this technique of ceramic material synthesis was much faster and better than conventional methods. The whole reaction process only takes 30 seconds because of ultrafast kinetics of crystallization.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Baolin Guo,Xiaokang Li,Yiwen Wu,Qing Yao
Microwave dielectric ceramics, as a novel electronic material, had been extensively utilized in the fabrication of radio frequency components for communication systems, including filters, dielectric antennas, and radar applications. While dry pressing remained the most prevalent method for filter fabrication, this study proposed an innovative gel casting system for manufacturing ceramic waveguide filters. The developed system employed Hydantion epoxy resin (HER) as the gelling agent, polyethyleneimine (PEI) as the curing agent, and MgTiO 3 -CaTiO 3 (MCT) ceramic powder (exhibiting dielectric properties of ε r = 20.5, Q×f = 55,000 GHz, and τ f = ±10 ppm/°C) as the dielectric material. Experimental results demonstrated that incorporating 13 wt.% Hydantoin epoxy resin with 0.7 wt.% polyacrylic acid (PAA) dispersant yields a well-dispersed ceramic slurry containing 80 wt.% solid loading. After drying, the green body was sintered at 1400 °C for 3 h at air atmosphere. This process resulted in densified samples with homogeneous microstructure and optimized microwave dielectric properties. Building upon this foundation, a fourth-order waveguide filter was designed and fabricated with a center frequency of 3.5 GHz, bandwidth of 300 MHz, and return loss exceeding 15 dB. Compared to conventional dry pressing techniques, the gel casting approach demonstrated distinct advantages in simplified processing and cost-effectiveness. Its superior near-net-shape forming capability for complex geometries proved potential applications in next-generation 5G/6G microwave devices.
研究领域:
材料科学
·
电气工程
·
微波技术
·
通信系统
·
陶瓷工艺
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Weijia Guo,Peiyao Zhao,Zhenxing Yue
Passive electronic components made from dielectric ceramics can hardly operate at extremely high temperatures, which is attributed to the sharply increasing dielectric loss and leakage conductance. In this work, the widely applicated CaTiO 3 ceramics are used as the matrix, and the high-temperature electrical properties are modified by doping Sm 3+ and Al 3+ . The Sm-doping in CaTiO 3 ceramics can significantly suppress the dielectric relaxation at low frequencies and reduce the high-temperature leakage conductance. Continued doping of Al in Ca 0.6 Sm 0.27 TiO 3 ceramics can further reduce the high-temperature dielectric loss and conductivity. These changes are associated with tighter crystal structures and fewer defects in the ceramics. With Sm and Al doping, the high-temperature dc conductivity of the ceramics is reduced by about 4 orders of magnitude, and a dielectric loss of less than 0.02 and a low temperature cofficient of capacitance (TCC) of − 25 ppm/℃ are obtained over a wide temperature range of room temperature to 530 ℃. Outstanding temperature stabilities are exhibited over a temperature range of 25 ∼ 200 ℃ in energy storage performance and charge-discharge property. Extremely fast discharge speed ( t 0.9 = 16 ns) makes it suitable for pulsed power electronic systems. Such linear dielectric materials are expected to be used in harsh environment of high temperatures.
研究领域:
材料科学
·
电气工程
·
陶瓷
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）