Article
Engineering, Multidisciplinary
Ying Zhao, Dazhi Ding
Summary: In this study, a discontinuous Galerkin time-domain method based on volume surface integral equation (VSIE) is investigated to analyze the transient electromagnetic scattering of composite conducting dispersive dielectric objects. The method utilizes triangular basis functions for temporal basis and handles the dispersion convolution relations analytically. The proposed method demonstrates flexibility and efficiency in several numerical examples.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Mathematics, Applied
Meiramkul Amangaliyeva, Muvasharkhan Jenaliyev, Sagyndyk Iskakov, Murat Ramazanov
Summary: This paper examines the solvability of a singular integral equation arising in the theory of boundary value problems for the heat equation in an infinite angular domain, and investigates the general solution representation of a nonhomogeneous integral equation. Estimates for the resolvent and the solution of the boundary value problem are also established in the study.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Mathematics, Applied
Carlos Fresneda-Portillo, Zenebe Woldemicheal
Summary: In this study, the interior Dirichlet boundary value problem for the diffusion equation in nonhomogeneous media is transformed into a system of boundary-domain integral equations (BDIEs) using a parametrix from Portillo (2019). The research also extends previous results for the mixed problem in a smooth domain to Lipschitz domains and PDE right-hand side in the Sobolev space H-1(Ω), proving the equivalence between the system of BDIEs and the original BVP, as well as their solvability and solution uniqueness in appropriate Sobolev spaces.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Mathematics, Applied
Carlos Fresneda-Portillo, Zenebe Woldemicheal
Summary: This study simplifies the interior Dirichlet boundary value problem for the diffusion equation in nonhomogeneous media to a system of boundary-domain integral equations using a parametrix obtained in Portillo (2019). Results from Portillo (2019) are further extended to Lipschitz domains with a PDE right-hand side in the Sobolev space H-1(Omega), where neither classical nor canonical conormal derivatives are well-defined. Equivalence between the system of BDIEs and the original BVP is proven, along with their solvability and solution uniqueness in appropriate Sobolev spaces.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Engineering, Electrical & Electronic
Shaode Huang, Chao-Fu Wang, Jin Pan, Deqiang Yang, Ming-Chun Tang
Summary: A new surface integral equation-based formulation for the characteristic modes of lossless composite metallic-dielectric objects is proposed in this study, which provides a more compact and easier-to-implement solution compared to existing formulations. The formulation allows for simultaneous retrieval of full modal electric and magnetic currents, both of which are equiphase. The derivation of this formulation avoids the commonly used process of current elimination, and numerical results demonstrate its accuracy in providing modal solutions to lossless composite metallic-dielectric problems.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Multidisciplinary
Marcelo David, Andrey Shendrik, Yuri Feldman, Paul Ben Ishai
Summary: In this paper, a novel Full Multiple Reflections algorithm for extracting the complex dielectric permittivity of materials over a wide range of frequencies is reported and evaluated. The method analyzes the influence of multiple reflections due to non-idealities and impedance mismatches to improve accuracy and overcome the drawbacks of using non-ideal transmission lines.
Article
Engineering, Electrical & Electronic
Wenyang Zhou, Yikai Chen, Shiwen Yang
Summary: This article explores characteristic modes for metallic-dielectric composite structures (MDCS) to analyze scattering from large antenna arrays efficiently and accurately. By using modal currents as basis functions in the MoM, the method reduces the number of unknowns and CPU time, improving computational efficiency. Numerical results of typical antenna arrays with MDCS demonstrate the efficiency and accuracy of the proposed method.
INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS
(2021)
Article
Engineering, Multidisciplinary
Amr Ashraf Ibrahim, Ahmed Fady Farid, Youssef F. Rashed, Mohamed El -Attar
Summary: In this paper, alternative static-like fundamental solutions for transient dynamic analysis of three-dimensional elasticity are developed by modifying Navier's equations of elastodynamics and using a suitable finite difference scheme. The new fundamental solutions are derived using operator decoupling technique and are used to solve non-homogeneous media by dividing them into multi regions. The stiffness and load vector of each region are calculated using the boundary integral equation approach. The proposed solutions are more stable and accurate than previous time domain and dual reciprocity formulations, as demonstrated by numerical examples.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Energy & Fuels
Teng Wen, Xiang Cui, Xuebao Li, Hao Ma, Zhibin Zhao
Summary: This paper proposes a method to solve the transient electric field and charge density on the dielectric interface with high accuracy, using nodal finite element method in space and finite difference method in time. The proposed method is validated through a 2-D numerical example and compared with existing methods, showing a comparable or higher numerical accuracy.
CSEE JOURNAL OF POWER AND ENERGY SYSTEMS
(2022)
Article
Chemistry, Physical
Xiangyu Wang, Jiqing Lv, Yue Xu, Lingcui Zhang, Yan Shen, Huanfu Zhou, Di Zhou, Kaixin Song, Hai Guo, Feng Shi
Summary: The complex phase structures, lattice vibrational properties, and intrinsic properties of Ca1-xBaxWO4 composite microwave dielectric ceramics were investigated. The structure-property relationships were obtained using Raman spectroscopy, and the excellent dielectric properties of the CBWO ceramic at x = 0.25 were elucidated.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Engineering, Marine
Hossam Ragheb, Adam Sobey
Summary: This study examines the impact of transitioning from steel risers to composite materials on safety factors, uncovering uncertainties and changes in dynamic response, as well as the influence of extensibility on predicted results.
Article
Computer Science, Interdisciplinary Applications
Qingyun Yao, Haibing Wang
Summary: A numerical scheme for solving an initial-boundary value problem for the time-fractional diffusion equation is developed based on the boundary integral equation method. This scheme involves stable discretization for layer potentials, rewriting layer potential operators as generalized Abel integral operators in time and establishing a stable time discretization scheme using the composite trapezoidal rule. The efficiency and accuracy of the proposed numerical scheme are demonstrated through several numerical examples.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Engineering, Multidisciplinary
Lin Wang, Jinwei Gao, Huaguang Bao, Dazhi Ding
Summary: This article focuses on the research of dielectric breakdown phenomenon during high power microwave propagation. A three-dimensional multi-physics electromagnetic-thermal model is developed and solved by spectral-element time-domain method to accurately capture the physical mechanisms of electrical breakdown, thermal effect, and nonlinear effect. The research is significant for the protection of high power microwave devices.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Multidisciplinary
G. S. Cheng, Fayi Sun, Dazhi Ding
Summary: In this paper, an enhanced adaptive cross approximation algorithm is proposed to analyze the narrow-band transient electromagnetic scattering from three-dimensional perfect electrically conducting objects. The algorithm accelerates the matrix-vector multiplication during the iteration solution, improving the accuracy and efficiency of the solution.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Computer Science, Interdisciplinary Applications
Wanquan Mei, Yuanyou Xia, Gaosheng Han, Peng-Zhi Pan, Mei Li, Zhide Wang
Summary: This paper focuses on the transient responses of shallow-buried structures subjected to time-varying disturbances. Analytical investigations based on the wave function expansion method reveal that the velocity vibrations and dynamic stress concentration around tunnels are significantly affected by the wavelength-to-diameter ratio, disturbance direction, and embedment depth. The theoretical findings can provide practical value for the support of shallow tunnels.
COMPUTERS AND GEOTECHNICS
(2021)
Article
Engineering, Electrical & Electronic
Peng-Yu Feng, Shi-Wei Qu, Ka Fai Chan, Shiwen Yang, Chi Hou Chan
Summary: This article presents a design concept of integrative transmitarray antenna (TAA) with gain-filtering and low-scattering characteristics. The design combines a bandpass frequency-selective surface (FSS) element and a square dielectric post with antireflection pyramidal structures (SDPP) to achieve simultaneous control of in-band and out-of-band waves.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Kaizhe Guo, Chi Hou Chan, Dixian Zhao
Summary: This paper introduces the design and analysis of an oscillator-doubler architecture for generating THz signals, and presents a 0.3-THz signal generator based on this architecture. The circuit optimizes the load impedance of the doubler to achieve second harmonic generation and maximize power output. By implementing an inductor-sharing configuration and suppressing unwanted modes, the signal generator achieves higher power density and stability.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2022)
Article
Engineering, Electrical & Electronic
Qing Le Zhang, Bao Jie Chen, Kam-Man Shum, Chi Hou Chan
Summary: This brief introduces a miniaturized spoof surface plasmon polaritons (SPPs) load for planar terahertz (THz) circuit applications on thick substrate. The proposed SPP cell consists of a groove-shaped structure integrated with a folded stub, which enables large capacitance, reduced cutoff frequency, and miniaturization of the SPP size. The SPP load made of nickel (Ni) metal has high conductivity and high permeability, effectively absorbing the propagating electromagnetic wave.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2022)
Article
Chemistry, Multidisciplinary
Xinxin Gao, Ze Gu, Qian Ma, Wen Yi Cui, Tie Jun Cui, Chi Hou Chan
Summary: Driven by the demands for compact interconnects and fast information transfer, research on spoof plasmonic metamaterials has been focused on achieving individual modulation of amplitude or phase at single frequencies due to structural limitations. This study proposes and experimentally demonstrates an ultra-thin reprogrammable modulator consisting of a spoof surface plasmonic polariton (SSPP) waveguide and spoof localized surface plasmon (SLSP) resonators, allowing independent control of amplitude and phase of surface waves. By manipulating the SSPP waveguide and SLSP resonators in real-time, various programmable modulations such as amplitude-shift keying, phase-shift keying, quadrature amplitude modulation, and frequency-shift keying can be achieved. Measurement results confirm the potential applications of the reprogrammable plasmonic metamaterial in integrated circuits and communication systems.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Chenfeng Yang, Geng-Bo Wu, Baojie Chen, Ka Fai Chan, Chi Hou Chan
Summary: This article reports a reflective metasurface for steering Bessel beams at the terahertz band. By designing a multiresonance structure with a large reflection phase range, the desired phase distribution for generating off-axis Bessel beams can be achieved. The metasurface, composed of 79 x 79 half-wavelength elements with different dimensions, is capable of producing controllable Bessel beams by adjusting frequencies.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Multidisciplinary Sciences
Jing Cheng Zhang, Geng-Bo Wu, Mu Ku Chen, Xiaoyuan Liu, Ka Fai Chan, Din Ping Tsai, Chi Hou Chan
Summary: The development of the sixth-generation (6G) communication technology is in progress and it is expected to surpass the performance of the fifth generation. The precise control of information transfer direction and signal concentration is crucial in 6G technology.
Article
Engineering, Manufacturing
Xuexuan Ruan, Chi Hou Chan
Summary: This article introduces a novel method of designing filters using an optimization algorithm, which can autonomously evaluate filters using a fitness function. The approach eliminates the need for numerous simulations, saving time and computational resources, as well as extensive expertise. Experimental results designing microstrip and waveguide filters demonstrate the effectiveness of the proposed approach.
IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Xinxin Gao, Bao Jie Chen, Kam-Man Shum, Qian Ma, Wen Yi Cui, Tie Jun Cui, Chi Hou Chan
Summary: The next-generation wireless communications and intrachip and interchip communications require high-speed terahertz (THz) interconnects, which can be achieved using spoof surface plasmon polaritons (SSPPs). This study proposes and experimentally demonstrates planar multifunctional THz plasmonic devices based on the interaction between SSPPs and spoof localized surface plasmon (SLSPs). These devices enable pass-through transmission, multifrequency resonances, and phase shift in THz plasmonic systems, making them promising for on-chip integrations, wireless communications, and sensing systems.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Engineering, Electrical & Electronic
Chenfeng Yang, Geng-Bo Wu, Dongze Zheng, Ka Fai Chan, Chi Hou Chan
Summary: In this article, a wideband, ultralow-profile circularly polarized folded transmitarray antenna is proposed for millimeter wave applications. By controlling the orientations of the elements, the metasurface can manipulate the reflection and transmission of electromagnetic wavefronts, reducing the antenna profile and generating a high-gain beam.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Multidisciplinary Sciences
Geng-Bo Wu, Jun Yan Dai, Kam Man Shum, Ka Fai Chan, Qiang Cheng, Tie Jun Cui, Chi Hou Chan
Summary: The study proposes a microwave universal metasurface antenna (UMA) that can dynamically, simultaneously, independently, and precisely manipulate all properties of electromagnetic waves in a software-defined manner. The UMA has high integrability and programmability, and is expected to spark a surge of applications in various fields.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Ka Kit Kelvin Ho, Geng-Bo Wu, Bao-Jie Chen, Ka Fai Chan, Chi Hou Chan
Summary: This article presents a novel approach to reducing coma for transmitarray OFF-axis scanning in the THz region. A dual transmitarray solution is proposed, in which a transmitarray with an optimized phase profile is placed behind a regular phase profile transmitarray. Experimental validation shows good focusing performances of the dual-transmitarray antenna.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Yu-Xuan Xie, Geng-Bo Wu, Wen-Qiang Deng, Shu-Yan Zhu, Chi Hou Chan
Summary: This article proposes a millimeter-wave achromatic metalens antenna using 3D printing technology to reduce dispersion effects and enlarge bandwidth. The measured results show that the antenna has a maximum realized gain of 23.27 dBi, a return loss smaller than -15 dB within the entire operating bandwidth, and a broad 3-dB gain bandwidth of more than 68.4% covering the V and W bands.
IEEE OPEN JOURNAL OF ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Liang Gao, Chi Hou Chan
Summary: A differentially-fed shared aperture patch antenna with on-chip power combining and radiation function is proposed for a compact terahertz (THz) source design. A high-density parallel coupled oscillator topology is proposed to feed the antenna for high area efficiency. The prototype achieves a high dc-to-THz conversion efficiency and a peak EIRP of 29.6 dBm with a frequency tuning range of 4.9%.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Dongze Zheng, Chi Hou Chan, Ke Wu
Summary: Leaky-wave antennas have been widely studied and recognized for their highly directive beam, easy feeding mechanism, simple configuration, and frequency-driven beam-scanning. Functional leaky-wave antennas, which exploit radiating discontinuities and waveguiding structures, have become a key research focus in the development of modern wireless RF/microwave systems. This article provides a review and investigation of enabling concepts, structures, and techniques for designing functional leaky-wave antennas with low side-lobe and cross-polarization behaviors, rapid beam-scanning, stable radiation, frequency-selectivity, and open-stopband suppression.
IEEE JOURNAL OF MICROWAVES
(2023)
Article
Engineering, Electrical & Electronic
Liang Gao, Chi Hou Chan
Summary: This article presents a large-scale coherent terahertz (THz) source array with 144 coupled oscillator elements. A novel 2-D scalable coupling topology is proposed for large array formation, enabling high-frequency radiation without a lens. The design also allows for beam steering through bias voltage change. The fabricated chip is capable of radiating high power and high-frequency beam with low phase noise and high efficiency. The chip's compact size and tunable output frequency make it a promising solution for THz applications.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2023)
