Article
Chemistry, Multidisciplinary
Prasenjit Das, Pratim Kumar Chattaraj
Summary: Density functional theory (DFT) calculations were performed on Li-3 clusters encapsulated in B-40 and C-60 cages, showing shorter Li-Li bond lengths, higher vibrational frequencies, and spontaneous formation thermodynamically. Electron density analysis revealed the presence of a non-nuclear attractor (NNA) in the Li-3 cluster, with the Li-3@C-60 system exhibiting higher localization of electron density at the NNA.
FRONTIERS IN CHEMISTRY
(2021)
Article
Computer Science, Information Systems
Raza Ullah, Sadiq Ullah, Farooq Faisal, Rizwan Ullah, Dong-you Choi, Ashfaq Ahmad, Babar Kamal
Summary: In this study, an antipodal Vivaldi antenna was designed for 5th generation (5G) mobile communication and Ku-band applications. The antenna has three layers and compact size. It covers multiple frequency bands, shows high efficiency, and is suitable for 5G communication and radar applications.
Article
Chemistry, Analytical
Arun Kesavan, Mu'ath Al-Hassan, Ismail Ben Mabrouk, Tayeb A. Denidni
Summary: This paper presents a novel circular polarized dielectric antenna array for millimeter-wave applications at 30 GHz. The proposed antenna array features a wide resonance bandwidth and high gain, making it suitable for millimeter-wave wireless communication.
Article
Engineering, Electrical & Electronic
Zhuoqiao Ji, Guang-Hua Sun, Hang Wong
Summary: This study presents a design of an aperture-coupled complementary antenna for circularly polarized broadside radiation at millimeter-wave frequencies, combining a patch dipole and a folded loop antenna to generate two orthogonal electric field components in the far-field radiation.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Optics
Anirudh Bharadwaj, Shweta Vincent, Tanweer Ali
Summary: In this article, we propose the design of a Floret antenna for terahertz applications. It operates in a wide frequency range with high gain and radiation efficiency, making it suitable for terahertz detectors in high-frequency bands.
Article
Engineering, Electrical & Electronic
Hao-Tao Hu, Chi Hou Chan
Summary: This article presents a wideband filtering antenna based on SIW structure for mm-wave applications, with wide impedance bandwidth and good filtering characteristics. By introducing specific structural designs, filtering responses in the lower and upper stopbands are achieved, making it suitable for 5G mm-wave backhaul communications.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Chen Zhao, Sheel Aditya, Shaomeng Wang
Summary: A novel coplanar slow-wave structure (SWS) for millimeter-wave backward-wave oscillator (BWO) application is proposed, featuring reduced dielectric loading effect with metal layer only on the top surface of the substrate. Suitable for fabrication using PCB or microfabrication techniques, this structure can be directly fed with coplanar waveguide (CPW) and covers a -15-dB S-11 frequency range from 13.7 to 120 GHz. Simulation results show a tunable frequency range of 32.7 GHz and a maximum output power of 22.7 W at 114 GHz for a BWO based on the proposed SWS, with good potential for microfabrication techniques.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Guang-Hua Sun, Hang Wong
Summary: In this article, a novel slot radiator is proposed for a broadband and high-gain antenna array for millimeter-wave applications. The antenna array achieves a wide impedance bandwidth and high efficiency, making it suitable for long-distance mmW communications and related applications.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Yichi Zhang, Dandan Wu, Zhao He, Fei Tian, Zilong Zhang, Meining Nie, Jianming Huang
Summary: In this article, a nonlinear vector network analyzer (NVNA) measurement setup is developed for the characterization of frequency modulated continuous wave (FMCW) signals in the frequency domain. The proposed NVNA setup, validated for high-accuracy measurement of wideband FMCW signals at millimeter-wave test bands, offers lower measurement errors and uncertainties compared to commercial real-time oscilloscopes and vector signal analyzers, providing a reference standard for test and calibration in automotive radar applications.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Li-Zhao Song, Pei-Yuan Qin, Shu-Lin Chen, Y. Jay Guo
Summary: This communication presents a transmitarray antenna with an elliptical cylindrical shape for wide-angle multibeam radiation. Through innovative design and experimental validation, the antenna demonstrates good beam coverage and scanning loss performance.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Jerzy Krupka, Bartlomiej Salski, Tomasz Karpisz, Pawel Kopyt, Leif Jensen, Marcin Wojciechowski
Summary: Complex permittivity measurements of irradiated high-resistivity float-zone silicon were conducted using three different resonance techniques, showing similar characteristics to intrinsic silicon under certain conditions.
IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS
(2022)
Article
Physics, Applied
Son Trinh-Van, Thai Van Trinh, Youngoo Yang, Kang-Yoon Lee, Keum Cheol Hwang
Summary: The proposed antenna is a millimeter-wave broadband circularly polarized magneto-electric dipole array antenna with wide overlapped AR/impedance bandwidth. A 2x2 CP array antenna incorporating an improved power divider network was developed based on the proposed CP antenna element. The demonstrated antenna showed excellent performance with a broad overlapped AR/impedance bandwidth, making it a good candidate for 5G mm-wave applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Xin Dai, Kwai Man Luk
Summary: A wideband dual-polarized magneto-electric (ME) dipole with 50% overlapped working bandwidth and gain up to 14.8 dBi is presented in this study. By combining antenna elements with single-layered feed networks, a 2 x 2 array is designed, fabricated, and measured, showing promising performance for millimeter-wave antenna in package (AiP) applications.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Peng Gu, Dixian Zhao, Xiaohu You
Summary: This brief presents the design of a wideband low-loss attenuator at W band, which utilizes a reflective-type attenuation topology to reduce loss and provide flat gain response. The optimized switched-resistor-based reflective loads enable simultaneous direct-digital control and dB-linear gain tuning. The implemented attenuator in 40-nm CMOS technology proves to cover a 15.5 dB gain range with a 0.5 dB step and exhibits a gain error of less than 0.2 dB RMS over the 70-110 GHz band, indicating low loss and flat gain response.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Chemistry, Physical
Shaoqiu Jiang, Rongguo Song, Zelong Hu, Yitong Xin, Guan-Long Huang, Daping He
Summary: In this paper, the authors proposed phased array antennas based on highly conductive graphene-assembled film for 5G millimeter wave applications. They designed and fabricated two different types of phased array antennas and demonstrated their advantages in terms of operating bandwidth and beam pointing performance.
Article
Nanoscience & Nanotechnology
Jiapeng Xu, Zhimin Liao, Qi Wang, Bo Liu, Xiaoli Tang, Zhiyong Zhong, Lei Zhang, Yuanjing Zhang, Huaiwu Zhang, Lichuan Jin
Summary: This study experimentally demonstrates that the transmission efficiency of low-k spin waves can be enhanced through surface metallization of yttrium iron garnet (YIG), resulting in increased group velocity and low spin-pumping efficiency. The competition between spin-pumping effects and the introduction of enhanced group velocity by metal decoration describes the essence of partial signal enhancement in the spin-wave transmission spectrum. The work provides a practical way to achieve spin-wave manipulation and low-loss transmission.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
Kui Liu, Cheng Liu, Jie Li, Lichuan Jin, Huaiwu Zhang
Summary: Li(1+x)2MgTi3O8 ceramics with Li non-stoichiometric ratios were prepared to inhibit Li volatilization. The effects of Li non-stoichiometric ratios on the sintering behavior, crystal structure, microscopic morphology, Raman vibrations, electron density, and dielectric properties were investigated. The Li(1+0.06)2MgTi3O8 ceramics demonstrated the best dielectric properties with er = 26.33, Q x f = 69 435 GHz (@6.87 GHz, 54% improvement), Tf = 2.95 x 10-6 degrees C-1. The improved ceramics have potential applications in microwave communication technology.
JOURNAL OF MATERIOMICS
(2023)
Article
Chemistry, Physical
Xu Xu, Haoyang Huang, Lichuan Jin, Tianlong Wen, Yulong Liao, Xiaoli Tang, Yuanxun Li, Zhiyong Zhong
Summary: Ni80Fe20 (NiFe) films were deposited on periodically rippled Al2O3 substrates by two different template oblique angle deposition (OAD) processes at various oblique deposition angles alpha (0 degrees <= alpha <= 60 degrees). The disparate in-plane uniaxial magnetic anisotropy (UMA) caused by the two template deposition processes of films was revealed by magneto-optical Kerr effect (MOKE) loops and ferromagnetic resonance (FMR) measurements. The analysis of Transmission electron microscopy images indicated that this was related to the different micromorphology of the films due to the two template deposition processes. The angle between substrates' ripple direction and the material flow incident direction would strongly influence the micromorphology and the induced in-plane UMA field of films.
SURFACES AND INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Cong Qi, Xizhi Yang, Yuanming Lai, Weiping Gong, Fangyi Huang, Xiao Li, Jun Yin, Gang Jiang, Chongsheng Wu, Hua Su
Summary: The nominal compositions of MgAl2-x(Zn2/3Nb1/3)(x)O-4 ceramics were synthesized using a solid-phase reaction method. It was found that the addition of Mg/ZnAl2O4 solid solution and second-phase Mg4Nb2O9 greatly improved the microwave dielectric properties of the samples. Furthermore, the second phase, ionic polarizability, and relative density influenced the dielectric constant (epsilon(r)) value. The quality factor (Qf) value exhibited a maximum at x = 0.40, and the temperature coefficient of the resonant frequency (tau(f)) value was negatively correlated with the B-site bond value. The ceramic with the nominal composition MgAl1.6(Zn2/3Nb1/3)(0.4)O-4 showed good microwave dielectric properties: epsilon(r) = 9.06, ultrahigh Qf = 563 000 GHz, and tau(f) = -45 ppm degrees C-1.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Physical
Xueying Wang, Yida Lei, Liang Shi, Jie Li, Lichuan Jin, Yulong Liao, Kui Liu, Huaiwu Zhang
Summary: The adjustment of crystal structures and properties by ion substitution has gained increasing interest in recent years for solving issues in LTCC microwave device preparation. In this study, Fe3+ ions were substituted in low-temperature sintered BaFe12O19, and the changes in microstructures, dielectric characteristics, and magnetic properties were examined. The results showed significant changes in the crystal lattice, dielectric properties, and magnetic parameters of BaM after the substitution of Ga3+ ions.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Electrical & Electronic
Shuaicheng Liu, Lichuan Jin, Qinghui Yang, Xiangrong Wang, Dainan Zhang, Huaiwu Zhang
Summary: This study reports a Ge1-x Bi x / Bi: thulium iron garnet (TmIG) spin heterojunction, which enhances the spin-orbit coupling (SOC) strength and improves the abnormal spin Hall effect (ASHE) and the spin Hall magnetoresistance (R (H)) switch characteristics by using Ge1-x Bi x and Bi:TmIG thin films.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Physics, Applied
Zijin Lin, Xinkai Xu, Lei Zhang, Junwen Wei, Zhiyong Zhong, Xiaoli Tang, Lichuan Jin
Summary: This study successfully enhanced the spin Hall angle by introducing dielectric material SrTiO3 into Pt. Theoretical analysis revealed that the enhancement of spin Hall angle is attributed to the complementary interplay between intrinsic mechanism from strong spin-orbit coupling in Pt and extrinsic mechanism from side-jump scattering caused by dielectric impurities. This work provides an effective strategy for fabricating low-power spin-torque devices with high-performance spin Hall materials.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Ceramics
Fanqiang Lin, Yuanming Lai, Baoyang Li, Yuanxun Li, Weiping Gong, Qin Zhang, Mingjun Xie, Chongsheng Wu
Summary: MgTi1-x(Co1/3Nb2/3)(x)O-3 ceramics were prepared by a solid-state reaction method. The crystal structure, grain growth, dielectric properties, and temperature coefficient of resonance frequency were investigated. It was found that the type and content of ions have an influence on the solubility of phases, formation of secondary phase, and grain growth. The impact of TiO6 octahedral distortion and ion polarizability on dielectric properties and temperature coefficient of resonance frequency were systematically discussed.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Jun Yin, Xiao Li, Yuanming Lai, Xi Zhang, Shengquan Yu, Yongzhi Luo
Summary: Transparent polycrystalline Al2O3 (PCA) ceramics with high transmittance in the visible and infrared bands were prepared by hot isostatic pressing. The transmittance in the visible light region was significantly improved by the HIP method. The pure Al2O3 ceramics prepared using the same process showed a high quality factor and are potential candidates for multilayer electronic devices.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Yaning Lin, Lichuan Jin, Linling Li, Hui Zheng, Huaiwu Zhang
Summary: Aluminum-doped hexagonal barium ferrite film with high perpendicular magnetic anisotropy (PMA) and remanence ratio was prepared by post-annealing at high temperature on Al2O3 substrate. The crystal structure measurements showed improved crystallinity and orientation after high temperature post-annealing, while diffusion of Al ions from the Al2O3 substrate into the ferrite film occurred at 1100 degrees C annealing temperature. The diffusion phenomenon was confirmed by the distribution of elements in the cross-section, resulting in a decrease in saturation magnetization and an increase in coercivity and remanence ratio. A hexagonal barium ferrite film with large PMA field, relatively small FMR linewidth, and high remanence ratio was obtained by annealing the film at 1100 degrees C, showing potential for application in self-biased microwave devices.
CHEMICAL PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Dainan Zhang, Zhu Tao, Lichuan Jin, Qinghui Yang, Qiang Li, Huaiwu Zhang
Summary: A garnet film with spatial magnetic moment distribution was grown on a gadolinium gallium garnet wafer (111) crystal plane by adjusting growth parameters and ion substitution. A spin heterojunction Pt1-xBix/(YLuBiCa)3(FeGa)5O12 with both ISHE and ASHE effects was designed and fabricated. The spatial magnetic moment distribution of the heterojunction was found, providing a foundation for spin injection in multiple directions.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Youbin Zheng, Dainan Zhang, Lichuan Jin, Yulong Liao, Yiheng Rao, Qinghui Yang, Xiangrong Wang, Huaiwu Zhang
Summary: A Ge1-x Bix alloy film was grown into a GeBi/yttrium iron garnet (YIG) spin heterojunction with a ferromagnetic insulator Y(3)Fe(5)O(12) garnet film wafer for the first time, and it was found that regulating the Bi ions content and enhancing the spin-orbit torque (SOT) can control the signal voltage amplitude, bandwidth, and waveform of the inverse spin Hall effect (ISHE). The Bi doping not only changes the electron concentration and mixing conductance of the GeBi/YIG bilayer but also increases the SOT between GeBi film and YIG film, thereby driving domain superfast reversal and enhancing the ISHE. Our research shows that the Ge1-x Bix/YIG (x = 11.6-22.7%) spin heterojunction is one of the best choices for future spin wave devices.
ACS MATERIALS LETTERS
(2023)
Article
Chemistry, Physical
Lei Zhang, Huaiwu Zhang, Dainan Zhang, Yuanpeng Li, Tianlong Wen, Zhiyong Zhong, Lichuan Jin
Summary: Antiferromagnetic oxides have unique properties in spintronics and are affected by crystal lattice defects. The role of vacancy-induced ferromagnetism on terahertz spin current in antiferromagnetic nickel oxide thin films is investigated. The results show that nickel vacancies break the antiferromagnetic exchange coupling and lead to the coexistence of antiferromagnetism and ferromagnetism in NiO thin films. The enhancement of terahertz radiation in NiO thin films with the strongest ferromagnetism is significant. The findings highlight the importance of defects in antiferromagnetic spintronics in the terahertz field.
Article
Materials Science, Ceramics
Fanqiang Lin, Chongsheng Wu, Qisheng Yin, Yuanming Lai, Yingli Liu
Summary: In this study, the effect of Ba substitution on the spiral magnetic structure and magnetoelectric effect in polycrystalline Z-type hexaferrites was systematically investigated. The results showed that Ba substitution significantly improved the magnetoelectric coupling coefficient and extended the magnetic field range for the appearance of magnetoelectric signals. These improvements were attributed to the decrease of Fe-O-Fe bond angle, reduction of cone angle in the transverse conical spin structure, and change in the distribution of magnetic Co ions caused by Ba substitution.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Materials Science, Ceramics
Mingjun Xie, Xiao Li, Yuanming Lai, Cong Qi, Jun Yin, Weiping Gong, Yuanxun Li, Qian Liu, Chongsheng Wu
Summary: “In this study, high-entropy spinel-type ceramics were synthesized and their microwave dielectric properties were investigated. The high-entropy ceramics exhibited good dielectric performance, which was influenced by factors such as sintering temperature, lattice distortion, and grain size.”
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
