JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2026
·
IF 16.8
Jing Ye Jin,Mo Wei,Yu Hui Huang,Qing Wei Zhou,Kai Xin Song,Bing Liu
Achieving a near-zero temperature coefficient of resonant frequency ( τ f ) while maintaining high quality factor ( Q ), typically reported as Q × f ( Qf ), in microwave dielectric ceramics is a significant challenge. In this work, a core-shell structural engineering strategy is proposed for efficient τ f regulation in MgF 2 –0.5 wt% LiF (MFL0.5) ceramics, which exhibit excellent microwave dielectric performance ( ε r = 5.09, Qf = 100,733 GHz) but suffer from a large negative τ f (−67.4 ppm/°C). Instead of dispersing temperature-compensation phases throughout the matrix, a pre-densified TiO 2 ceramic with positive τ f is introduced as a compact core embedded within the MFL0.5 shell, forming an integrated core-shell architecture. Experimental results show that a near-zero τ f of −1.97 ppm/°C can be achieved with only ∼1.27 wt% TiO 2 , while retaining a high Qf value of 50,302 GHz. In contrast, conventional MFL0.5–TiO 2 composite ceramics require 20 wt% TiO 2 to achieve similar τ f compensation, resulting in a significant decrease in Qf to 25,933 GHz. Electric-field distribution simulations highlight the enhanced electric filling factor of the TiO 2 core, which plays a key role in efficient τ f regulation. This core-shell architecture provides a highly effective strategy for regulating τ f with minimal dielectric loss penalty, offering a promising pathway for the development of high-performance, low- ε r microwave dielectric ceramics for advanced communication systems.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Jiangyu Zhang,Jie Li,Yihua Sun,Liang Fang
LiYbO 2 ceramic with tetragonal structure formed only by [LiO 6 ] and [YbO 6 ] octahedra, exhibited a ε r of 13.3 ± 0.2, Q × f of 24,700 ± 500 GHz and an abnormal positive τ f of + 38.6 ± 3.0 ppm/°C as sintered at 1100 °C with low relative density of 88 %. Dense ceramic with relative density of 95.1 % was obtained with the addition of 1 wt% LiF when sintered at 1080 °C, exhibiting enhanced microwave dielectric properties of ε r = 14.3 ± 0.2, Q × f = 41,200 ± 500 GHz, τ f = +56.5 ± 3.0 ppm/°C and α L = 8.5 × 10 −6 /K. The large positive discrepancy as much as + 45.1 % between measured ε r with porosity correction and calculated ε r (C-M) using Clausius−Mossotti relations might be due to the rattling effect of Li + , which also led to the positive τ f .
研究领域:
材料科学
·
物理学
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高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Ning Zhang,Ning Guan,Jian Li,Qingfeng Li,Huaicheng Xiang,Weishuang Fang,Yang Yang,Peilin Qing,Ying Tang,Liang Fang
A series of tetragonal scheelite-type Ca 1- x La x W 1- x Ta x O 4 (CLWT x , x = 0.1–0.4) ceramics were successfully fabricated using the traditional solid-state sintering method. The effects of A- and B-site dual substitution on phase formation, microstructural morphology, and microwave dielectric performance were comprehensively characterized using X-ray diffraction, Rietveld refinement, Raman spectroscopy, and scanning electron microscopy. The results revealed that single-phase scheelite ceramics were obtained over the compositional range x = 0.1–0.3, whereas a secondary Ca 0.5 TaO 3 phase emerged at x = 0.4. Within the single-phase scheelite solid-solution region (0.1 ≤ x ≤ 0.3), the unit cell volume expanded linearly from 315.07 Å 3 to 321.15 Å 3 with increasing substitution level, accompanied by elongation of A–O bonds and contraction of B–O bonds. The bond valence analysis indicated that the co-substitution strategy effectively mitigated the rattling effect of the overall crystal structure. Consequently, the τ f increased monotonically from −41.10 ppm/°C to +8.12 ppm/°C, with a near-zero τ f of −7.22 ppm/°C achieved at x = 0.3. The Q × f decreased gradually from 69,172 GHz to 61,630 GHz for x = 0.1–0.3, primarily attributed to reduced packing fraction, decreased lattice energy, and enhanced Raman FWHM. The optimal microwave dielectric properties (εr = 16.4, Q × f = 61,630 GHz, τ f = - 7.22 ppm/°C) were obtained for CLWT 0.3 ceramic sintered at 1400 °C. Furthermore, a cylindrical dielectric resonator antenna was designed and simulated, which exhibited a reflection coefficient S 11 of −47.90 dB, an impedance bandwidth of 200 MHz, and a radiation efficiency exceeding 93% at 3.99 GHz, demonstrating the potential of this material for S-band wireless communication applications.
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Feilong Liu,Junqi Chen,Huaicheng Xiang,Jie Li,Yang Yang,Ying Tang,Liang Fang
In this work, two novel hexagonal magnetoplumbite-type LaMGa 11 O 19 (M = Mg, Zn) ceramics were prepared and deeply investigated. XRD patterns, SAED and HRTEM images analysis results demonstrated that the LaMGa 11 O 19 (M = Mg, Zn) ceramics are formation of hexagonal magnetoplumbite structure with a space group of P 6 3 / mmc . Both ceramics exhibited relatively high density (>95 %) and large positive τ f (+145.1 and + 136.7 ppm/°C), combined with moderate ε r around 20 and reasonable Q × f values of 19,328 GHz and 22,197 GHz, which be used as a temperature compensator for LTCC applications. The intense rattling effect of La 3+ cations resulted in abnormally high dielectric constant with a large positive variation by a factor of over 0.70 from the theoretical values calculated using the Clausius-Mossotti formula according to each ion's polarizability, negative τ αm , and positive τ f values. The P–V–L chemical bond theory analysis and impedance spectroscopy showed that the large dielectric loss might result from the high ionicity of the La-O bond and conduction loss, thus leading to relatively low Q × f for the LaMGa 11 O 19 (M = Mg, Zn) ceramics.
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CERAMICS INTERNATIONAL
·
2026
·
IF 6
Shu-An Ye,Maolong Qiao,Yuanlu Xu,Jiaying Yan,Chenglong Li,Renjia Yuan,Ziyi Xiong,Guohao Xie,Yi Xiong,Xiaoming Zhang,Kang Du
In this work, a series of Na (1- x ) Ca (1+ x ) Ga (1+ x ) Si (2- x ) O 7 (0 ≤ x ≤ 0.9) ceramics were successfully prepared via the conventional solid-state reaction method, achieved the synergistic substitution of Ca 2+ for Na + and Ga 3+ for Si 4+ in NaCaGaSi 2 O 7 ceramic. The crystal structure evolution, microwave dielectric properties, and structure-performance relationships of the Na (1- x ) Ca (1+ x ) Ga (1+ x ) Si (2- x ) O 7 ceramics were systematically characterized by multiple analytical techniques including XRD Rietveld refinement, XPS, far-infrared spectroscopy, and first-principles calculations. The synergistic dual-ion substitution effectively optimized the microstructure of NaCaGaSi 2 O 7 -based ceramics, suppressed the formation of oxygen vacancy defects, and modulated the chemical bonding characteristics, thereby significantly improving the comprehensive microwave dielectric performances. Notably, the Na (1- x ) Ca (1+ x ) Ga (1+ x ) Si (2- x ) O 7 ( x = 0.7) ceramic achieved excellent comprehensive properties: ε r = 9.01, a high Q×f value of 31049 GHz, and a small negative τ f value of −13.36 ppm/°C. Furthermore, a high-gain dielectric patch antenna fabricated using the optimized ceramic substrate achieved a peak gain of 10.66 dBi and a maximum radiation efficiency of 85.68% at 13.63 GHz, verifying the great application potential of Na (1- x ) Ca (1+ x ) Ga (1+ x ) Si (2- x ) O 7 ceramics for Ku-band communication applications.
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Xinlei Shen,Chun Tong,Haikui Zhu,Yigang Qian,Lixi Wang
(1- y )Ca 0.97 Sr 0.03 B 2 O 4 - y TiO 2 composite ceramics were produced through a solid-phase reaction procedure, ensuring that all samples had a uniform and dense microstructure, where each constituent phase exhibited complete crystallinity. Their crystal structures, microwave dielectric properties, microstructures, and co-sintering performance at low temperatures were thoroughly investigated. To enhance the thermal stability of the resonant frequency, rutile TiO 2 ( τ f = +450 ppm/°C) was introduced as an additional phase during the preparation of the composite ceramics. According to the XRD analysis, the characteristic peak signals became more pronounced as the content of rutile TiO 2 in the composite gradually rose, and the peak intensity was found to vary linearly with the relative content of TiO 2 . SEM analysis revealed that the TiO 2 additions ( y = 0.05, 0.10, and 0.15) resulted in tightly arranged grains, the absence of visible pores, and a high degree of densification. However, as the TiO 2 content increased ( y = 0.20, 0.25), pores appeared, grain boundaries became more pronounced, and densification decreased. At y = 0.15 and a sintering temperature of 900 °C, the best dielectric properties were achieved for the (1- y )Ca 0.97 Sr 0.03 B 2 O 4 - y TiO 2 composite ceramics: ε r = 7.61, Q×f = 33,983 GHz, and τ f = +3.51 ppm/°C. By introducing TiO 2 , the initially negative τ f was effectively adjusted toward zero, thereby achieving greater thermal reliability. Additionally, the absence of interfacial chemical reactions between the composite ceramic and the silver after co-firing indicates that the material possesses favorable chemical compatibility with silver, demonstrating strong applicability in LTCC technology.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Hui Yan,Weiwei Wang,Yue Ma,Yong Shang,Lingxiu Shu,Yun Wang,Yue Xu,Bo Wu,Xingang Ren,Xianliang Wu,Gang Wang
Thermally stable x Ba 5 Si 8 O 21 - (1- x ) Ba 2 Si 3 O 8 and x Ba 5 Si 8 O 21 - (1- x ) Ba 2 Si 3 O 8 - z wt% LiF ceramics were successfully synthesized via a conventional solid-state reaction method. In the x Ba 5 Si 8 O 21 - (1- x ) Ba 2 Si 3 O 8 (0.1 ≤ x ≤ 0.8) ceramics, only Ba 5 Si 8 O 21 and Ba 2 Si 3 O 8 phases coexisted, with their phase contents confirmed by the Rietveld refinements. The 0.4Ba 5 Si 8 O 21 -0.6Ba 2 Si 3 O 8 ceramic, composed of 40.98 wt% Ba 5 Si 8 O 21 and 59.02 wt% Ba 2 Si 3 O 8 phases, exhibited near-zero τ f and moderate Q × f values. The phase composition controlled the τ f and Q × f values of x Ba 5 Si 8 O 21 - (1- x ) Ba 2 Si 3 O 8 (0.1 ≤ x ≤ 0.8) ceramics. Moreover, the addition of 3 wt% LiF as a sintering aid reduced the sintering temperature of the 0.4Ba 5 Si 8 O 21 -0.6Ba 2 Si 3 O 8 ceramic to 875 °C, while no other secondary phases were detected in the 0.4Ba 5 Si 8 O 21 -0.6Ba 2 Si 3 O 8 - z wt% LiF ceramics. The 0.4Ba 5 Si 8 O 21 -0.6Ba 2 Si 3 O 8 -3 wt% LiF ceramic demonstrated a dense microstructure and favorable microwave dielectric properties ( ε r = 7.44, Q × f = 8293 GHz and τ f = 2.37 ppm/°C), highlighting its potential for low-temperature co-fired ceramic (LTCC) applications.
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高影响因子
Frontiers in Materials
·
2020
·
IF 2.705
Tian Huanrong,Liu Xin,Yang Yaokang,Wu Haitao,Zhang Zhiliang
Ce2(Zr0.94Sn0.06)3(MoO4)9 (CZSM) ceramics were synthesized via a traditional solid-state method. The effects of Sn-substitution on phase composition, microstructure, and microwave dielectric properties as a function of sintering temperature were discussed. The XRD results indicated that all the samples exhibited a single phase. The chemical bonds of CZSM ceramics were calculated based on P-V-L theory, which could be used to evaluate the relationship between structure and microwave dielectric properties. The tendency of dielectric constant was depended on the theoretical dielectric polarizability and bond ionicity. Moreover, the improvement of Q·f value was ascribed to the increase of packing fraction. The reduced τf value could be explained by decrease of the bond energy, enhanced the co-efficient of thermal expansion and increase of bond valence (VZr(Sn)). The complex permittivity values were obtained from infrared reflectivity spectra. The dielectric permittivity and loss were 10.92 and 3.08 × 10−4, respectively, which agreed well with the measured value. Typically, the optimal microwave dielectric properties of εr = 10.35, Q·f = 59,660 GHz (at 9.70 GHz), and τf = −7.52 ppm/°C were achieved in CZSM ceramics sintered at 800°C for 6 h.
研究领域:
材料科学
·
陶瓷工程
·
固体化学
·
电磁材料
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高影响因子
APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Mingjia Lu,Xin Ouyan,Songping Wu,Rongyun Ge,Rui Xu
Self-assembled porous ZnGa 2 O 4 particles were synthesized through a facile hydrothermal route in this work. The phase evolution and microstructure of specimens were identified by XRD and SEM. Various morphologies (i.e. porous, nanorods or spherical particles) and size (nano or micro-sized) could be rationally designed through altering the reaction conditions. Hydrothermal ZnGa 2 O 4 particles exhibited an outstanding microwave dielectric performance, i.e. a dielectric constant of 9.93, a Q × f value of 73 000 GHz, and a τ f value of –68.7 ppm/ °C. What is more, the ZnGa 2 O 4 ceramics displayed a stable quality factor in the high temperature region (1400–1500 °C) due to the unique frame-structured ZnGa 2 O 4 particles. Therefore, they can be regarded as potential candidate materials for millimeter-wave device.
研究领域:
材料科学
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微波工程
·
化学合成
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yucheng Cao,Liangbin Zhang,Hongrong Mei,Zhenggang Rao,Tingfang Tian,Chunchun Li
The monoclinic diopside structured CaMgGe 2 O 6 dielectric ceramics were synthesized by the traditional solid-phase reaction method, and their microwave dielectric properties were characterized. X-ray diffraction (XRD) and Rietveld refinement revealed that CaMgGe 2 O 6 belongs to the monoclinic system of space group C2/c. SEM images showed that dense CaMgGe 2 O 6 ceramics could be formed at the optimum sintering temperature of 1300 °C. Typically, ceramic sintered at 1300 °C for 6 h possessed outstanding microwave dielectric properties with ε r ∼7.96, Q × f ∼41,280 GHz, and τ f ∼ −46.6 ppm/°C. Far-infrared spectra analysis revealed the intrinsic microwave dielectric properties of CaMgGe 2 O 6 ceramics. These findings demonstrate promising application prospects of CaMgGe 2 O 6 in microwave substrate materials.
研究领域:
材料科学
·
陶瓷
·
微波工程
·
介电材料
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高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2023
·Vol. 57
·期 1
·015301
·
IF 3.4
Xiao Zhang,Zhe Xiong,Bin Tang,Chengtao Yang
The rapid advancement of mobile communications technology is imposing greater demands on electronic components. Microwave dielectric ceramics with a high dielectric constant (r) are crucial for the miniaturization and integration of microwave devices. Herein, The perovskite-structured (Ca0.61Nd0.26)1−x(Li0.5Nd0.5)xTiO3 (0 ⩽ x ⩽ 0.8) microwave dielectric ceramics with high r value were prepared by solid-state reaction method. The results demonstrated that the r value reached its peak at x = 0.6, which was influenced by the bond valence at B-sites. The τf and Q× f values decreased with increasing x value. Doping (Li0.5Nd0.5)2+ at A-sites led to an increase in the full width at half maximum of Raman peaks, indicating higher internal loss. A high dielectric constant and temperature-stable (Ca0.61Nd0.26)0.27(Li0.5Nd0.5)0.73TiO3 ceramic can be sintered with good microwave dielectric properties of r = 129.4, Q× f= 2,787 GHz, and τf = +1.9 ppm/°C.
研究领域:
材料科学
·
电气工程
·
微波技术
·
陶瓷
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 102
·期 7
·4092-4102
·
IF 2.956
Yunhui Zhang,Haitao Wu
La 2 (Zr 1− x Ti x ) 3 (MoO 4 ) 9 (0 ≤ x ≤ 0.1) ceramics were prepared by the traditional solid-state reaction method. XRD analysis showed that La 2 (Zr 1− x Ti x ) 3 (MoO 4 ) 9 (0 ≤ x ≤ 0.1) ceramics belonged to a trigonal system. Based on the chemical bond theory, the consequences of bond energy, bond ionicity, lattice energy, and thermal expansion coefficient of ceramics on microwave dielectric properties were discussed. As Ti 4+ addition was increased, the reduction in dielectric constant was ascribed to the fact that the polarizability of Ti 4+ is smaller than Zr 4+ , and the downward trend was related to the bond ionicity. Besides, the tendency of Q·f value depended on the packing fraction and the lattice energy. The improvement in τ f value, the increase in bond energy, and the decrease in the coefficient of thermal expansion were all correlated. The far-infrared spectra implied that the absorptions of structural phonon oscillation were the main reason for the maximum polarization contribution. La 2 (Zr 0.92 Ti 0.08 ) 3 (MoO 4 ) 9 ceramics sintered at 750°C for 4 hours exhibited the best dielectric properties ( ε r = 10.33, Q·f = 80 658 GHz, and τ f = 3.48 ppm/°C).
研究领域:
材料科学
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陶瓷工程
·
电气工程
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高影响因子
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