CHINESE JOURNAL OF POLYMER SCIENCE
·
2022
·Vol. 41
·期 2
·288-296
·
IF 3.815
Tan Wan-Yi,Jian Ling-Feng,Chen Wei-Peng,Zhang Yong-Wen,Lu Xiao-Chuang,Huang Wan-Jun,Zhang Ji-Sheng,Wu Jing-Wu,Feng Jun-Li,Liu Yi-Dong,Cui Ting-Ting,Min Yong-Gang
Modified polyimides (MPIs) show great potential towards 5G communication applications, due to its excellent thermal stability, mechanical property and chemical stability as compared to most of polymers. Introducing fluoride groups or porous structure is favorable to ultra-low dielectric constant ( D k ) and dielectric loss ( D f ). However, the cost of the fluorinated MPIs is high and their synthetic processes are complicated, and porous MPIs suffer poor mechanical properties. Also, increasing the fraction of free volume is a very effective way to lower D k through introducing more ultra-low- D k air component. However, most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D f , hindering the application of MPIs in high-speed communication devices. Thus, it is highly desirable to develop intrinsic ultra-low- D k / D f MPIs at high frequency with less fluoric groups and nonporous structure. Herein, we introduce a facile and effective strategy to lower D k and D f through introducing rigid and large sterically hindered aromatic groups into MPIs. On the one hand, their large steric hindrance effect leads to low D k by increasing intrinsic free volume. On the other hand, the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D f by inhibiting dipole orientations. Based on this strategy, the spirobifluorene groups are preferred. The as-prepared MPIs show excellent dielectric performance with low D k of 2.74–2.76 and low D f of 0.00599 at 10 GHz, to some extent, exceeding the multiple fluorinated MPI with D k / D f of 2.67/0.00663 at 10 GHz.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Jin Fang,Tao Ni,Minmin Mao,Yu Liu,Huan Liu,Lei Cao,Xueqing Yu,Bing Liu,Hadi Barzegar Bafrooei,Liang He,Yingjie Ren,Fayaz Hussain,Dawei Wang,Kaixin Song
MgSiO 3 ceramics with a low dielectric constant are highly promising for application in 5G communication due to their excellent performance and cost-effectiveness. However, the application remains constrained by phase transitions. This study aims to unlock their full potential by introducing Cu ions to mitigate phase transitions, thereby achieving stable and superior performance. Mg 1- x Cu x SiO 3 (0 ≤ x ≤ 0.25) ceramics were synthesized by solid-state method, and the effects of Cu introduction on the crystal structure, phase constitution, microstructure and microwave dielectric properties were systematically investigated. Through XRD patterns and Rietveld refinement , it was found that when x = 0, both protoenstatite (PEN) and low-temperature clinoenstatite (CEN) phases coexist due to a phase transition from PEN to CEN. As x increases, the PEN phase dominance rises while the CEN phase diminishes, indicating that the addition of Cu ions inhibits the occurrence of phase transition. At x ≥ 0.2, only the orthoenstatite (OEN) phase was observed. SEM and EDS analyses revealed the beneficial impact of Cu introduction on sintering, yet excessive amounts can lead to abnormal grain growth , local segregation, and uneven distribution of Cu elements, thereby deteriorating microwave dielectric properties . The optimal microwave dielectric performance was achieved at x = 0.05: ε r = 6.2, Qf = 93,600 GHz, τ f = −33.7 ppm/°C. A one-year long-term comparative study revealed the stabilizing effect of Cu incorporation for obtaining stable excellent performance. These findings underscore the potential of introducing an appropriate amount of Cu to achieve stable and superior microwave dielectric properties in MgSiO 3 ceramics, paving the way for practical applications in 5G communication.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Ruixiang Deng,Bingbing Chen,Haogeng Li,Ke Zhang,Tao Zhang,Yun Yu,Lixin Song
Microwave absorbers serve the purpose to ensure the transmission efficiency and accuracy in 5G telecommunications. Two-dimensional MXene has great potential in absorbing microwave. In this study, MXene(Ti 3 C 2 T x )/Co 3 O 4 composites are successfully fabricated by a facile and stable hydrothermal treatment in concentrated strong base and Argon environment, followed by a one-step annealing process. Phase composition , chemical state of elements, morphology and structure of the new composite materials are studied by systematical characterization. It is revealed that adsorbed Na + ions and terminations, which are generated at the interface during hydrothermal treatment in concentrated NaOH solution, can protect the Ti 3 C 2 T x from being decomposed. The synthesis mechanism is also proposed for stable fabrication of other MXene-based composite materials. The MXene/Co 3 O 4 composite is able to perform single-band absorption, multiband absorption and even broadband absorption in 2–18 GHz band by tuning its composition and thickness. Particularly, better than 90% absorption in a wide range of 10.8–17 GHz can be achieved with a thickness of just 2 mm. Enhanced wideband absorption originates from the multilayer structure , the surface defects , the conductivity of Ti 3 C 2 T x and the capacitance structure of Co 3 O 4 . Ultrathin and broadband high absorption features make the material a promising candidate for future application.
研究领域:
材料科学
·
电磁材料
·
通信技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2022
·Vol. 51
·期 7
·3896-3902
·
IF 2.047
Cheng Jiawen,Qing Zhenjun,Wang Jin,Zhao Yun,Zhou Xin,Zou Huapeng,Li Haiyan,Li Yingxiang
In this paper, the traditional solid-phase reaction sintering process was used to synthesize Ca 1-x Mg x V 2 O 6 (x = 0.03, 0.06, 0.09, 0.12) ceramics under low-temperature conditions. The effects of partial replacement of Ca 2+ by Mg 2+ on the A-site on the crystalline type, sintering temperature, microstructure, densification, and microwave dielectric performances of Ca 1-x Mg x V 2 O 6 ceramic were studied. The only crystalline phase of CaV 2 O 6 was observed in the ceramics. The sintering densification and dielectric performances of the Ca 1-x Mg x V 2 O 6 ceramic show a trend of first increasing and then decreasing with the increase of Mg 2+ content. The addition of Mg ions can effectively increase the Q × f value of the Ca 1-x Mg x V 2 O 6 ceramics but cannot improve the τ f value. The Ca 0.91 Mg 0.09 V 2 O 6 ceramic sintered at 725°C displayed good microwave dielectric performances: ε r = 10.41, Q × f = 68524 GHz, and τ f = − 36.8 ppm/°C. The good dielectric properties of this ceramic can meet the development needs of 5G communication technologies.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 11
·7585-7596
·
IF 3.9
Heming Li,Xinming Wang,Yuze Gong,Hongbin Zhao,Zhaobin Liu,Lin Tao,Youyou Peng,Ke Ma,Zhizhi Hu,Davoud Dastan
Dielectric properties of polyimide (PI) are constrained by its inherent molecular structure and inter-chain packing capacities. The compromised dielectric properties of PI, however, could be rescued by introducing trifluoromethyl and forming a host–guest inclusion complex with the introduction of crown ethers (CEs). Herein, we report PI/crown ether composite films as a communication substrate that could be applied under high frequency circumstances. In this work, three kinds of bisphenol A-containing diamine (2,2′-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-methyl-4-aminophenoxy)phenyl]propane, and 2,2-bis[4-(2-trifluoro methyl-4-aminophenoxy)phenyl]propane) are synthesized and polymerized with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride to prepare low-dielectric PI films by means of thermal imidization. Crown ethers are introduced into the PI with different mass fractions to obtain three series of PI films. Following the combination of trifluoromethyl into the molecular chain of PI, high frequency dielectric loss of modified PI films can be effectively reduced. The properties of these materials (especially the dielectric properties) are thoroughly explored by crown ether addition. The results show that the crown ether addition process can offer crown ethers with increased free volume of PI matrix, thus allowing them to generate a special necklace-like supramolecular structure, which makes the crown ether disperse more uniformly in the PI matrix, resulting in improved dielectric properties. Importantly, the dielectric constant and dielectric loss of the composite films at high frequencies are remarkably reduced to 2.33 and 0.00337, respectively. Therefore, these composite films are expected to find extensive use as a 5G communication substrate at high frequencies in the future.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Fangyi Huang,Jiaqing Du,Xiaoli Tang,Qin Zhang,Xingyu Huo,Yuanxun Li,Xian Jian,Hua Su
Ba 0.8 Sr 0.2 CuSi 2 O 6 ceramics have a low dielectric constant, which is useful for low-latency 5G communication. To enable the preparation of Ba 0.8 Sr 0.2 CuSi 2 O 6 low-temperature co-fired ceramic (LTCC) materials, LBSCA and LBBS were used in this paper to reduce the sintering temperature of Ba 0.8 Sr 0.2 CuSi 2 O 6 . The effects of LBSCA and LBBS on the phase composition, densification, microscopic morphology, and vibrational characteristics of the ceramics were investigated by X-ray diffraction, scanning electron microscopy, density measurements, and Raman spectroscopy , and the causal factors influencing the microwave dielectric properties with the addition of glass were analyzed. It was found that 0.4 wt% LBSCA glass and 1 wt% LBBS glass reduced the sintering temperature to 925 °C, and these prepared ceramics had excellent microwave dielectric properties. The ceramic prepared with 0.4 wt% LBSCA glass had an ε r value of 7.672, Q × f value of 37193 GHz, and τ f value of −14.93 ppm/°C, while the ceramic prepared with 1 wt% LBBS glass had an ε r value of 7.512, Q × f value of 32136 GHz, and τ f value of −13.92 ppm/°C. The phase composition of the ceramics did not significantly change, indicating that neither glass reacted with the ceramics. The ε r value was affected by both density and Raman shift, the trend in the Q × f values was consistent with the density, and the τ f value decreased with increasing glass content, which was attributed to the liquid phase generated by the glass in the ceramic. In addition, co-firing these glass-doped ceramics with Ag at a low temperature resulted in good chemical compatibility. Combined with the near-zero τ f , these results demonstrate the excellent promise of these two ceramics as alternative materials for LTCC microwave devices and their application in 5G communication.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Changzhi Yin,Kang Du,Zhengyu Zou,Xiaoqiang Song,Ying Xiong,Fei Wang,Meng Zhang,Weicheng Lei,Yaodong Liu,Wenzhong Lu,Chunchun Li,Wen Lei
A novel microwave dielectric ceramic of SrGa 2 Si 2 O 8 was synthesized using the traditional solid-state method. Its phase composition, microstructure, and microwave dielectric properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy , and network analyzer . XRD results indicated that the space group of the ceramic transformed from I 2 /c to P 21 /a at 700 °C. A combination of good microwave dielectric properties was obtained at 1260 °C with ε r = 6.3, Q × f= 96,600 GHz and τ f = −45.2 ppm/°C at 16.5 GHz. The negative τ f can be tuned to near zero by adding 15 mol% CaTiO 3 . The densification temperature can be reduced to 940 °C by adding 4 wt% LiF. Moreover, the SrGa 2 Si 2 O 8 ceramic had good chemical compatibility with the Ag electrode. A patch antenna was designed using the 0.85SrGa 2 Si 2 O 8 + 0.15CaTiO 3 + 4 wt% LiF ceramic. The antenna had a high radiation efficiency of 99.2 % and a gain of 2.988 dBi at the center frequency of 4.261 GHz. All results indicated that the SrGa 2 Si 2 O 8 ceramic has promising potential for applications in 5 G wireless communication technology.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Zhiqian Yao,Yuxin Liu,Yong Zhang,Xueru Zhang,Yunfei Wu,Jiewu Cui,Jiaheng Wang,Yan Wang,Jiaqin Liu,Yucheng Wu
With the advancement and escalating demands of 5 G communication, low-frequency bands (2–8 GHz) have emerged as a pivotal area of focus in the research of electromagnetic wave (EMW) absorption. While magnetic metals and alloys have demonstrated efficacy in low-frequency absorption, they are hampered by high density, limited absorption bandwidths, and the complexities involved in tuning the absorption bands. This study presents a core-shell architecture where flaky iron carbonyl powder (FCIP) is encapsulated within lanthanum-doped silica (SiO 2 ), thereby significantly enhancing its low-frequency absorption capabilities. By meticulously adjusting the La 3 + doping content, we have successfully achieved tunable microwave absorption within the 5 G new radio (NR) bands, with a specific focus on the n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), and n79 (4.4–5.0 GHz) frequency ranges. The minimum reflection loss (RL min ) of the composites is −54.86 dB at a thickness of 2.81 mm. The incorporation of La 3+ into the silica shell induces a synergistic magnetic/dielectric effect, significantly augmenting impedance matching and wave absorption. Based on a strategically devised La 3+ doping approach, we have engineered an architecture that manifests gradient metamaterial characteristics, achieving an ultra-wide effective absorption bandwidth (EAB) spanning from 1.2 to 18 GHz. This research not only provides a practical methodology but also unveils a novel strategy to substantially enhance the microwave absorption performance of traditional metal alloys and their compounds.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Wen-Bo Li,Li-Xia Pang,Xiao-Long Wang,Wei-Guo Liu,Xiaogang Yao,Huixing Lin,Jin-Chao Miao,Di Zhou
This study examines the microwave dielectric properties of the Na 2 O–Bi 2 O 3 –Ln 2 O 3 –MoO 3 (Ln = Sm and Y) system, synthesized via a solid-state process at ultra-low sintering temperatures ranging from 600°C to 660°C. The X-ray diffraction and Rietveld refinement results suggested that a tetragonal sheelite phase was found in the x Na 5 Bi(MoO 4 ) 4 –(1− x )Na 5 Ln(MoO 4 ) 4 (0.05 ≤ x ≤ 0.20) ceramics. Scanning electron microscopy (SEM), backscattered electron image (BSE) and energy dispersive spectrometer (EDS) results indicated that the complex substitution of Bi 3+ produced a significant effect on the microstructural morphology. Besides, the substitution of Bi 3+ for (Sm 0.3 Y 0.7 ) 3+ effectively reduced the sintering temperature to 630°C. The variation of theoretical dielectric polarizabilities (α theo. ), the polarizability density (α theo. / V m ), the observed dielectric constant (ε r ), theoretical dielectric constant (ε theo. ), packing fraction (PF) values, and bond valence ( V i ) as a function of x value were investigated, which was helpful for understanding microwave dielectric properties. The ceramic composition 0.1Na 5 Bi(MoO 4 ) 4 –0.9Na 5 Ln(MoO 4 ) 4 sintered at 630°C for 2 h demonstrated the best microwave dielectric properties, exhibiting a ε r ∼ 9.3, Q × f value of about 31,200 GHz (at 11 GHz) and a temperature coefficient (τ f ) of −41.3 ppm/°C. Both XRD and EDS results indicated that the 0.1Na 5 Bi(MoO 4 ) 4 –0.9Na 5 Ln(MoO 4 ) 4 ceramic was chemically compatible with Ag at its sintering temperature (630°C). The x Na 5 Bi(MoO 4 ) 4 –(1− x )Na 5 Sm 0.3 Y 0.7 (MoO 4 ) 4 (0.05 ≤ x ≤ 0.20) ceramics in the Na 2 O–Bi 2 O 3 –Ln 2 O 3 –MoO 3 (Ln = Sm and Y) system are promising candidates for 5G and its successor 6G mobile communication technology.
研究领域:
材料科学
·
电子陶瓷
·
微波通信
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Siyu Xiong,Xiaowei Zhu,Guobin Zhu,Deqin Chen,Hongbo Cui,Laijun Liu,Chunchun Li
A microwave dielectric ceramic based on lithium aluminum silicate (LiAlSi2O6) with ultralow permittivity was synthesized using the traditional solid-state reaction technique, and its dielectric characteristics at microwave frequencies are presented. The nominal LiAlSi2O6 ceramic exhibited a relative permittivity of 3.95. To enhance the material properties, LiAlSi2O6-x wt % B2O3 microwave dielectric ceramics were fabricated by incorporating a low-melting-point sintering aid (B2O3), achieving a relative density exceeding 94%. The resultant ceramics exhibited a relative permittivity (εr) ranging from 3.95 to 4.42, a microwave quality factor (Q × f) between 24,720 and 28,990 GHz, and a resonant frequency temperature coefficient (τf) varying from −45.9 to −20.6 ppm/°C. Additionally, the introduction of B2O3 broadened the sintering temperature window and effectively lowered the optimal sintering temperature from 1400 to 1200 °C. Furthermore, LiAlSi2O6 ceramics demonstrated a near-zero coefficient of thermal expansion (CTE) of 1.44 ppm/°C, which is advantageous for applications requiring high thermal stability. Based on LiAlSi2O6-2.0 wt % B2O3 ceramics with εr = 4.42, Q × f = 28,990 GHz, and τf = −20.6 ppm/°C, a microstrip patch antenna was designed and fabricated. Testing of the antenna revealed exceptional performance, including a center frequency of 4.98 GHz, a bandwidth of 280 MHz (−10 dB), and a total efficiency reaching up to 93.7%. These findings underscore the promising potential of this material in advanced microwave and wireless communication applications.
研究领域:
材料科学
·
无线通信
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Qun Diao,Yong Zeng,Jimin Chen
With the rapid advancement of 5G communication technology, higher communication frequencies have pushed the development of the Luneburg lens (LL) towards greater integration and miniaturization. In this paper, a novel Zn 2 SiO 4 -TiO 2 (ZST) ceramic Flat Luneburg Lens (FLL) for the K-band is designed and successfully fabricated using vat-photopolymerization (VPP) 3D printing technology. By optimizing the rheological properties of the slurry alongside the photopolymerization and thermal treatment processes, the resulting ZST ceramic exhibits excellent microwave dielectric properties after sintering at 1250 °C: a dielectric constant ( εᵣ ) of 9.6933, a quality factor ( Q×f) reaching 85294 GHz, a frequency temperature coefficient ( τ f ) close to zero (-0.78 ppm/°C), and an extremely low dielectric loss (1.29×10 -4 ). Building upon this high-performance ZST ceramic, a miniaturized FLL with a diameter of 30 mm and a thickness of 4 mm was successfully fabricated via metamaterial structural design. The measured results indicate that the FLL achieved a maximum gain enhancement of 5.5 dBi. This work offers useful insights into the 3D printing manufacturing of high-performance microwave dielectric ceramics and their application in miniaturized and integrated radio frequency devices.
研究领域:
材料科学
·
通信工程
·
电子器件
·
增材制造
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Hong Li,Feng Bao,Xiaoqian Lan,Shuanger Li,Haoran Zhu,Yadong Li,Mingliang Wang,Caizhen Zhu,Jian Xu
With the rapid development of 5G communications, the traditional interlayer dielectric material polyimide (PI) requires modification due to its intrinsically high dielectric constant (D k ), high dielectric loss (D f ), and high moisture absorption, which make it difficult to meet the needs of the high-frequency communications industry. In this paper, a new strategy for the preparation of novel PI with intrinsically low D k and D f is proposed from the perspective of molecular structure design, the modification effect of superimposing bulky triphenyl pyridine structures and strong electronegativity groups, combined with long-chain anhydride to reduce the density of the imide structure. Therefore, three bulk diamine monomers (BPAB, PBAB3F, PBAB6F) containing triphenyl pyridine structures were designed in this paper and polymerized with 4,4′-(4,4′-isopropyldiphenoxy) phthalic anhydride (BPADA) to obtain three new PIs (PI-H, PI-CF 3 , PI-2CF 3 ) with different fluorine contents, focusing on the relationship between structure and properties, especially the effect of fluorine content on dielectric properties . The results of the study show that the dielectric and hygroscopic properties of PI improve with increasing fluorine content. Among them, PI-2CF 3 has the best overall performance, showing low dielectric (D k = 2.72@10 GHz & D f = 0.00233@10 GHz), high transparency (Cut-off wavelength (λ 0 ) = 389 nm, Maximum transmittance (T via ) = 89%) and low hygroscopicity (Water absorption (M a ) = 0.246%, Contact angle (C a ) = 111°).
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）