IEEE ANTENNAS AND PROPAGATION MAGAZINE
·
2021
·Vol. 63
·期 5
·118-144
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IF 2.593
Ziyang Zheng,Yue Ping Zhang
This article presents a finite difference time domain (FDTD) analysis of a probe-based millimeter-wave (mm-wave) far-field antenna measurement setup. First, it is found that a full-wave simulation of the entire setup requires formidable computational resources, and thus a reasonable simplification of the setup model is made. Then, an electric dipole antenna operating at 28 GHz is placed in the setup, and the reflected/scattered/refracted/absorbed/diffracted/obstructed field distribution and distortion on radiation patterns by equipment are simulated. Finally, a quiet zone assessment is conducted.
研究领域:
电磁学
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天线工程
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毫米波技术
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Hongwei Yang,Yong Ren,Fang Xu,Yulong Liao,Xiaoyu Li,Guixiang Liu,Bo Dai
Prior studies predominantly utilized solid-state sintering to fabricate Ni-based ferrite ceramics, aiming to enhance magnetic properties. While some researchers have adopted the hot-pressing method for preparing these ceramics, the resultant porosity remained elevated (>2 %), leading to an increased ferromagnetic resonance linewidth (Δ H ). The impact of high temperature and pressure during the forming process on Δ H and gyromagnetic properties in nickel-based ferrite ceramics has been seldom explored using hot pressing. Building on prior research involving solid-state sintering of Ni-based ferrite, this study employed a vacuum hot-pressing sintering technique to further optimize the gyromagnetic properties of the ferrite. A systematic investigation was conducted to understand the influence of porosity, grain size, and microstructure on the magnetic attributes of Ni ferrite ceramics. Under conditions of high pressure (48 MPa) and zero holding time, as the hot-pressing sintering temperature rose from 800°C to 1050°C, the average grain size expanded from 0.4 μm to 3.36μm. Concurrently, the relative density and saturation magnetization initially increased before decreasing. Consequently, a NiCuZn ferrite characterized by uniform, dense grains (GS ave =1.94 μm and D r =99.2 %) and good gyromagnetic properties (4π M s =4703 Gs and Δ H =277 Oe) was achieved through hot-pressure sintering at approximately 950°C.
研究领域:
材料科学
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电磁学
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2024
·
IF 11.2
Wei Wang,Jian Bao,Changhao Wang,Guoqiang He,Xin Wang,Diming Xu,Biaobing Jin,Zhongqi Shi,Moustafa Adel Darwish,Yawei Chen,Qixin Liang,Meirong Zhang,Di Zhou
The advancement of millimeter-wave communication desires the ceramic substrate with low permittivity ( ԑ r ) to meet the requirements of high transmission rates, low latency and wide bandwidth. However, the thermal conductivity of most low- ԑ r ceramics is too low to deal with heat dissipation in millimeter-wave applications. In this paper, we reported novel dielectric ceramics Li M SiO 4 ( M = Ga, Sc and Y) with excellent performances of low ԑ r (< 10) and high thermal conductivity (> 6 W mK −1 ). Their dielectric properties in both microwave and THz were investigated, where the LiGaSiO 4 ceramic achieved the lowest ԑ r of ∼5.2, the LiScSiO 4 ceramic presented extremely low loss ( Q × f ∼ 96,700 GHz, Q = 1/dielectric loss, f is resonant frequency), and the LiYSiO 4 ceramic showed a positive temperature coefficient of f (TCF ∼ +32 ppm °C −1 ). The distinct dielectric behavior was subsequently studied by structure-performance relationship in terms of M -site cations and bond parameters using bond valence theory, Phillips–Van Vechten–Levine chemical bond theory and so on. Moreover, a 36 GHz microstrip array antenna was designed and simulated using the LiGaSiO 4 ceramic substrate, obtaining high realized gain, high radiation efficiency and low sidelobe. The result demonstrated the great potential of LiMSiO 4 -type dielectric ceramics in millimeter-wave communications.
研究领域:
材料科学
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电子工程
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通信技术
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Huan Liu,Lei Cao,Jiachao Gu,Xinjiang Luo,Xueqing Yu,Ge Wang,Zhilun Lu,Yuanyun Hu,Yasemin Tabak,Atilla Evcin,Matjaz Spreitzer,Wenjun Li,Kaixin Song
In this work, we successfully integrated the high-entropy concept into LiMgPO 4 -based ceramics by strategically substituting Mg 2+ with various divalent ions. Through a low-temperature solid-phase reaction method, a series of high-entropy LiMg 0.9 R 0.1 PO 4 (R = Ni, NiCo, NiCoZn, NiCoZnCu, NiCoZnCuMn) ceramics were prepared successfully, and their MW dielectric properties were found to be heavily influenced by the ionic character, lattice energy, bond energy, entropy, ion radius disorder, and electronegativity of chemical bonds. Remarkably, LiMg 0.9 (Ni 0.2 Co 0.2 Zn 0.2 Cu 0.2 Mn 0.2 ) 0.1 PO 4 (LM5RP) ceramics exhibited exceptional MW dielectric properties ( ε r = 7.43, τ f = − 27.6 ppm/°C, and Q × f = 83,216 GHz@13 GHz and 105,889 GHz@28 GHz) when sintered at an extraordinarily low temperature of 900 °C for 2 h. To demonstrate the real-world applicability of the LM5RP high-entropy ceramic, we designed and fabricated a state-of-the-art millimeter-wave (mmWave) filter, operating at 28 GHz, using low-temperature co-fired ceramic (LTCC) packaging technology. The filter exhibited unparalleled performance, featuring a low insertion loss (0.9 dB) and wide stopband suppression (> 17 dB @ 2.14 f 0 ). These groundbreaking findings underscore the immense potential of high-entropy ceramics in revolutionizing advanced MW applications, particularly in the domain of B5G/6 G mmWave communication systems.
研究领域:
材料科学
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电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Meng Fei Zhou,Cheng Chao Hu,Jian Bing Yin,Yu Jiang,Bing Liu,Kai Xin Song
SrF 2 is a promising low- ε r fluoride with outstanding microwave dielectric properties , while densification of SrF 2 ceramics is challenging via traditional thermal sintering (TTS). In this work, dense SrF 2 ceramics with 93.4%–97.2% relative density have been obtained via cold sintering (300 MPa–900 MPa, 150 °C, 1 h) and subsequent post-annealing at 950 °C/3 h. The pretreated cold sintering process is beneficial for microstructure optimization, where the maximum Qf value (62,037 GHz) is obtained at 750 MPa, nearly three times higher than the TTS sample (21,080 GHz). An ultra-low dielectric constant ( ε r ) of 5.94 is simultaneously obtained, together with a temperature coefficient of resonant frequency τ f = −78.26 ppm/°C. Good chemical compatibility between SrF 2 ceramics and silver is verified, indicating great promise for their use in LTCC technology. Moreover, the low- ε r and high Qf values of the cold sintering optimized SrF 2 ceramics suggest great potential in the 5G millimeter-wave antenna systems. A SrF 2 -based dielectric resonator antenna is designed and fabricated, which resonates at the desired 24.5 GHz and exhibits an outstanding S 11 of −43.95 dB and a broad bandwidth of 4.51 GHz.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2021
·Vol. 9
·期 40
·14359-14370
·
IF 7.393
Lingxia Li,Xubin Wang,Weijia Luo,Shun Wang,Tian Yang,Ji Zhou
Miniaturization, power dissipation and temperature stability are the most critical factors restricting the microwave use of ceramic-based devices. Balancing them, especially for the ceramics with high dielectric constant, is a great challenge. Herein, a new strategy by trivalent ion (Al3+ and Ga3+) co-substitution is put forward in tungsten bronze structural Ba4Nd9.33Ti18O54 ceramics for millimeter-wave metamaterials, and a nearly 40% increase in Qf values with stable temperature characteristics is obtained. The crystal symmetry, morphology and the vibration modes are characterized by XRD, EDS and Raman spectroscopy, suggesting the varied internal strain and oxygen octahedron tilt from the mismatch of different cations. The best performance of Ba4Nd9.33Ti18−x(Al0.4Ga0.6)xO54−0.5x (BNT-AGx) is observed when x is 2.4: εr = 67.71, Qf = 13 675 GHz, τf = +4.4 ppm °C−1. Considering the dispersion relationship of BNT-AGx ceramics further, the structure of BNT-AGx metamaterials is uniquely designed, and the sub-wavelength BNT-AGx blocks are also fabricated to demonstrate the frequency selection filtering function with high temperature stability at the millimeter-wave band (>30 GHz), which is of great significance to achieve some eMBB (Enhanced Mobile Broadband) scenes of 5G (the 5th Generation) technology, from a metal loaded cavity to free space.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 104
·期 9
·4659-4668
·
IF 3.784
Chao Du,Mao-Sen Fu,Di Zhou,Huan-Huan Guo,He-Tuo Chen,Jian Zhang,Jun-Ping Wang,Shao-Fei Wang,Hai-Wen Liu,Wen-Feng Liu,Long Li,Zhuo Xu
Microwave dielectric ceramics are considered to be one of the key materials for dielectric resonators (DR) and have very broad application prospects in the fifth generation (5G) mobile communication system. Here we have prepared high-quality factor Y 3 Al 5 O 12 (YAG) transparent dielectric ceramics using high-purity α-Al 2 O 3 and Y 2 O 3 powders by cold isostatic pressing of the vacuum sintered with tungsten meshes as the heating elements. Optimum relative permittivity ( ) ~10.53, quality factor Q × f (Q = 1/dielectric loss, f = resonant frequency) ~95, 270 GHz (at =7.37 GHz), and temperature coefficient of resonant frequency (TCF) ~ −51.7 ppm °C −1 were obtained at a sintering temperature of 1780°C for 12 h. For the first time, YAG transparent ceramic dielectric resonator antenna (DRA) is designed as a dominant mode and a higher-order mode using the aperture coupling feeding configuration excitation. The proposed transparent dielectric ceramic DRA can provide a broad impedance bandwidth of 4.193 GHz (ranging from 21.90 to 26.09 GHz) for S 11 < −10 dB, radiation efficiency of 92.1%, and compact DR unit. The proposed DRA can be used potentially as a 5G millimeter (mm)-wave multiple-input-multiple-output (MIMO) antenna unit.
研究领域:
材料科学
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通信工程
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
Nano-Micro Letters
·
2024
·Vol. 16
·期 1
·1-17
·
IF 31.6
Liu Chuyang,Xu Lu,Xiang Xueyu,Zhang Yujing,Zhou Li,Ouyang Bo,Wu Fan,Kim Dong-Hyun,Ji Guangbin
The frequency and intensity of multi-magnetic resonance are freely regulated by co-doping La 3+ and Zr 4+ ions.
Zr 4+ occupation is elaborately modified for promoting the portion of polarization/conduction loss to increase profoundly.
The optimized electromagnetic characteristics lead to an ultra-wide bandwidth of 12.5+ GHz around millimeter-wave atmospheric window.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Cell Reports Physical Science
·
2024
·
IF 7.9
Bing Liu,Juan Liu,Cheng Chao Hu,Kai Xin Song,Yu Hui Huang
Microwave dielectric ceramics (MWDCs) are essential in low-temperature co-fired ceramic (LTCC) technology, necessitating a low sintering temperature, low dielectric constant ( ε r ), and high quality factor ( Qf ). On the other hand, the mismatch in the coefficients of thermal expansion (CTEs) between MWDCs and electrodes poses reliability challenges. Here, we report BaF 2 -LiF ceramics to address the need for low- ε r , high- Qf materials with high CTEs. The BaF 2 -LiF ceramics exhibit improved properties, including a substantial decrease in sintering temperature from 1,025°C to 700°C, enhanced relative density from 90.8% to 97.3%, and optimized Qf values increased by 20%. Moreover, the resulting ceramics demonstrate a high CTE of 20.6 ppm/°C, ensuring compatibility with polymer-based laminates and metal electrodes. Additionally, the BaF 2 -LiF ceramics serve as a promising dielectric resonator for high-performance millimeter-wave antennas. This study presents a comprehensive approach to optimize BaF 2 ceramics, addressing key parameters for high-reliability LTCC electronics and millimeter-wave antenna applications.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2024
·
IF 4
Anthony Roucou,Xiujuan Wang,Jonas Bruckhuisen,Manuel Roca,Colwyn Bracquart,Robin Blanchart,Luyao Zou,Qian Gou,Arnaud Cuisset,Guillaume Dhont
3-methylcatechol (3MC) is a molecule of environmental interest due to its presence in the atmosphere during biomass burning events, leading to the formation of secondary organic aerosols. This paper goes one step further than the paper from A.S. Hazrah et al. (2022) [10] . A three-dimensional torsional potential energy surface was determined, confirming the existence of three rotamers for 3MC. One dimensional potential energy curves along the rotation of the methyl group were computed and fitted to estimate the barrier height in each conformer . Experiments were performed at low temperature in the microwave domain ( 2 − 20 GHz range) and, for the first time, in the millimeter-wave domain ( 70 − 110 GHz range) at T = 323 K with a specially designed heated absorption cell. The rotational linelist was fitted to provide updated spectroscopic parameters for the two 3MC conformers of lowest energies. In particular, the A − E splitting is observed in the microwave region for both conformers while in the millimeter-wave region, it is only seen for the conformer of the lowest energy.
研究领域:
环境科学
·
量子化学
·
大气科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yu Liu,Minmin Mao,Tao Ni,Huan Liu,Jin Fang,Lei Li,Hadi Barzegar Bafrooei,Feng Shi,Fayaz Hussain,Dawei Wang,Kaixin Song
As 5G communication technology advances into millimeter-wave frequencies, the demand rises for microwave dielectric ceramics with low dielectric constant and low dielectric loss. In this regard, Mg 2 SiO 4 emerges as one of the most promising candidates. Herein, Mg 2-x Ga x Si 1-x Al x O 4 (MGSA, x = 0∼0.03) ceramics were prepared by a solid-state reaction process employing heterovalent ion substitution strategy, achieving ultra-low loss and enhanced temperature stability of resonant frequency while maintaining low dielectric constant. The effects of the partial substitution of Ga 3+ for Mg 2+ and Al 3+ for Si 4+ in MGSA ceramics were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, infrared reflectivity spectra, and combined with P–V–L bond theory analysis. XRD results revealed a solid solution formation, while SEM images highlighted microstructure variations with increasing x. Based on P–V–L theory, it was found that the dielectric constant is mainly affected by average bond ionicity A f i , while τ f is mainly affected by bond energy E . The intrinsic loss determined Qf value, which is further validated by Raman and infrared spectra. The optimal performance for millimeter-wave applications was achieved at x = 0.01: ε r = 6.95, τ f = −37.7 ppm/ o C, Qf = 244,800 GHz (at 27.15 GHz).
研究领域:
材料科学
·
通信技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Juan Liu,Bing Liu,Cheng Chao Hu,Qing Wei Zhou,Kai Xin Song
(1– x )BaV 2 O 6 - x LiF ( x = 0.025, 0.05, 0.10, 0.15) ceramics with an ultra-low sintering temperature of 475 °C were synthesized using the standard solid-state reaction method. The ceramics demonstrated a remarkable enhancement in the quality factor ( Qf ), reaching a maximum value of 16,800 GHz at x = 0.10, which is 5.6 times higher than that of pure BaV 2 O 6 ceramics obtained in this work. A near-zero temperature coefficient of resonant frequency ( τ f = 1.44 ppm/°C) was simultaneously achieved, together with a dielectric constant ε r of 11.54. Additionally, the chemical compatibility between the present ceramics and the Al electrode was confirmed. Moreover, a millimeter-wave antenna with an excellent S 11 value of −50.3 dB, and a large bandwidth of 3.44 GHz was fabricated using the 0.9BaV 2 O 6 -0.1LiF ceramic as the dielectric resonator . These results highlight the potential application prospects of (1– x )BaV 2 O 6 - x LiF ceramics in the ultra-low temperature co-fired ceramic technology and 5 G millimeter-wave antennas.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
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