Article
Engineering, Electrical & Electronic
Zhenyan Wei, Yannan Jiang, Shitian Zhang, Xiuqin Zhu, Qingliang Li
Summary: This study proposes a broadband absorber based on graphene and one-dimensional photonic crystal to achieve magnetically tunable broadband absorption in the terahertz frequency range. The performance analysis demonstrates that the proposed absorber operates in a wide frequency range with high absorption, and can be dynamically tuned by varying the magnetic field.
IEEE PHOTONICS JOURNAL
(2022)
Article
Optics
Jingxuan Lan, Rongxuan Zhang, Hao Bai, Caidie Zhang, Xu Zhang, Wei Hu, Lei Wang, Yanqing Lu
Summary: In this study, a low-cost broadband tunable THz absorber based on one-step laser-induced graphene (LIG) was proposed, achieving over 90% absorption from 0.5 THz to 2 THz with optimized parameters.
CHINESE OPTICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Runhua Zhou, Tingting Jiang, Zhen Peng, Zhenyuan Li, Min Zhang, Shixing Wang, Ling Li, Huawei Liang, Shuangchen Ruan, Hong Su
Summary: The tunable broadband terahertz absorber designed in this paper consists of graphene, silica medium, and phase change material Vanadium dioxide (VO2). By adjusting the parameters of the absorber, different absorption rates can be achieved within different frequency ranges. This absorber can be widely used in fields such as THz tunable filters, sensors, switches, and modulators due to its large tunability.
Article
Physics, Multidisciplinary
Dan Hu, Tian-Hua Meng, Hong-Yan Wang, Mai-Xia Fu
Summary: The designed tunable metamaterial absorber demonstrated dual-broadband high absorption properties at terahertz frequencies, with absorption rates reaching over 90%. By adjusting the graphene chemical potential, the absorptivity can be dynamically controlled from less than 10% to nearly 100%. The absorber is polarization-insensitive and robust to incident angles, showing potential for applications in THz imaging, modulating, filtering, etc.
Article
Physics, Multidisciplinary
Wenwen Liu, Zhengyong Song, Weihua Wang
Summary: This article introduces a high-performance broadband absorber based on multilayer graphene squares for terahertz applications, with over 90% wave absorption in the frequency range from 1.45 THz to 4.35 THz and a bandwidth fraction of 100%.
Article
Materials Science, Multidisciplinary
Jiali Wu, Xin Yan, Xueguang Yuan, Yangan Zhang, Xia Zhang
Summary: The dual-tunable broadband terahertz absorber based on graphene and strontium titanate achieves ultra-wide bandwidth and high absorption rate through adjustments of Fermi energy and temperature. It is insensitive to incident angles and maintains stable performance, showing great potential for applications in tunable broadband terahertz absorbers.
RESULTS IN PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Zhipeng Ding, Wei Su, Hong Wu, Wenlong Li, Yuanhang Zhou, Lipeng Ye, Hongbing Yao
Summary: This article proposes a novel single-layered graphene metasurface absorber (GMSA) that achieves thinness, lightness, broadband, high absorption, and tunability. The GMSA differs from common hybrid patterns by adopting a graphene layer with a simple multi-square ring structure. The simulation results show that the GMSA can achieve broadband absorption in the terahertz frequency range, making it suitable for various applications.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Optics
Zongli Wang, Xin Wang, Junlin Wang, Huizhong Pang, Suyalatu Liu, Huqiang Tian
Summary: This paper introduces a graphene-based terahertz absorber with independently-tunable broadband absorption properties, achieving 90% absorption for both TE and TM polarizations in specific frequency ranges. The absorption can be continuously and independently controlled by changing the gate voltage, and the absorber is insensitive to the polarization state and maintains stability over a wide range of incident angles.
Article
Physics, Condensed Matter
Hanieh Ahmadi, Sedigheh Vaezi, Vahid Jafarzadeh Harzand, Reza Safian
Summary: A THz absorber composed of graphene ribbons and continuous sheet has been designed in this study, achieving high absorption efficiency. The research findings are significant for THz sensing and imaging applications, and the absorber can be fabricated using CVD technology.
SOLID STATE COMMUNICATIONS
(2021)
Article
Optics
Pei-Jung Wu, Wei-Cheng Tsai, Chan-Shan Yang
Summary: In this study, an electrically tunable multi-band terahertz (THz) metamaterial filter based on graphene and multiple-square-loop structures was designed. The structure consists of multiple metal square loops of different sizes, which correspond to different THz frequencies, achieving the expected efficacy of a multi-band wave filter. By sweeping external voltages, the capability of the high-sensitivity THz filter can be modulated from single-band to multi-band filtering by changing graphene's Fermi levels. This hybrid THz wave filter study shows promise for the development of selecting channels in THz and 6G communications.
Article
Physics, Condensed Matter
Pulimi Mahesh, Damodar Panigrahy, Chittaranjan Nayak
Summary: This study investigates the broadband absorption characteristics of graphene-layered random photonic crystals using the 4 x 4 characteristic matrix method. The results show that under the influence of a magnetic field, optimal semi-random photonic crystals can achieve broadband absorption greater than 84% in the wavelength range of 74.8-85.57 μm. The absorption band can be tuned by selecting the thickness of the silicon carbide layer. Numerical analysis demonstrates the enhancement of absorption and FWHM with the number of layers, Fermi level, and period number. The proposed absorber has potential applications in polarization selective absorbers, sensors, and terahertz imaging.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Yan Liu, Rui Huang, Zhengbiao Ouyang
Summary: This study presents a graphene metamaterial and STO-based terahertz absorber with tunable and switchable bifunctionality, allowing for broadband absorption and narrowband absorption functionalities with high absorption rates and performance.
Article
Chemistry, Analytical
Jing Li, Yanfei Liu, Yu Chen, Wenqing Chen, Honglei Guo, Qiannan Wu, Mengwei Li
Summary: We propose a functionally tunable terahertz (THz) metamaterial absorber, which can switch between broadband-narrowband and dual-broadband near-perfect absorption. This switching performance is achieved through the phase transition of Vanadium dioxide (VO2) and the tunable electrical property of graphene. Computer simulation technology (CST) microwave study verifies the switching absorption properties. The proposed absorber has potential applications in THz range, such as switches, electromagnetic shielding, cloaking objects, filtering, sensing, etc.
Article
Materials Science, Multidisciplinary
Jun Zhu, Changsong Wu, Yihong Ren
Summary: The study proposed a metamaterial absorber composed of graphene, and demonstrated that dynamic tuning of the absorption range and absorption bandwidth could be achieved by adjusting the Fermi level of the graphene. This has theoretical and engineering significance in the domains of thermal photo-voltaics, solar cells, and sensors.
RESULTS IN PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Hengli Feng, Zuoxin Zhang, Jingyu Zhang, Dongchao Fang, Jincheng Wang, Chang Liu, Tong Wu, Guan Wang, Lehui Wang, Lingling Ran, Yang Gao
Summary: This article proposed a dual broadband terahertz bifunction absorber that can be actively tuned to achieve perfect modulation of absorptance and absorption bandwidth. It also has the advantages of being polarization insensitive and maintaining stable absorption at wide angles of oblique incidence.
Article
Engineering, Electrical & Electronic
Yanxiu Li, Li-an Bian, Kai-da Xu, Yu Liu, Yaokun Wang, Ranhao Chen, Shu Xie
Summary: In this paper, a symmetrical and compact monopole MIMO antenna with two feeding ports is designed to minimize mutual coupling between antenna elements. L-shaped stubs and defective ground structure (DGS) are used, along with chip resistors, to achieve improved isolation. The path of electric current is altered using rectangular slots etched on the metal ground as DGS to further enhance isolation. Loading chip resistors controls coupling current on the stubs and further strengthens isolation. Simulation and measurement results indicate -36 dB mutual coupling, 0.002 envelope correlation coefficient (ECC), 9.99 dB diversity gain (DG), and a radiant peak gain of 4.03 dBi for the antenna.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Shangjing Xi, Jianying Guo, Yannan Jiang, Kai-Da Xu
Summary: This paper presents a compact and simple dual-band bandpass filter (BPF) design using only five pairs of coupled lines. The even- and odd-mode method is applied due to its symmetry structure. Six transmission zeros (TZs) are obtained and calculated through input impedance analysis. A dual-band narrowband BPF example is fabricated and measured, with center frequencies at 0.94 and 1.12 GHz. The measured results agree with the simulation results, validating the design process.
Article
Engineering, Electrical & Electronic
Yeqing Yin, Qinlong Li, Xiaoming Chen, Jianxing Li, Kai-Da Xu
Summary: A wide-angle scanning leaky-wave antenna based on double-layer double-row spoof surface plasmon polariton (SSPP) is proposed. The antenna utilizes double-layer glide-symmetry periodic SSPP to convert slow-wave mode into fast wave mode and achieve dual-beam radiation. The double-row zipper-shaped structure serves as a binary array for endfire radiation and improved gains. The designed antenna exhibits a wide scanning range of 136 degrees (-90 degrees-46 degrees) within the frequency range of 11-26 GHz, with a maximum gain of 13.1 dBi and gain fluctuation of 2.8 dB.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Shangjing Xi, Kai-Da Xu, Shuai Yang, Xue Ren, Wen Wu
Summary: This paper proposes a bandpass frequency selective surface (FSS) with low loss and angular stability based on three metal layers. The FSS structure is built by coupling the top and bottom resonant layers through a metal ring layer. The performance of the FSS is insensitive to the polarization and angle of the incident wave, and the prototype measurements agree with the simulations.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Kai-Da Xu, Yiqun Liu
Summary: A new millimeter-wave on-chip bandpass filter (BPF) using complementary-broadside-coupled (CBC) structure is proposed, and the calculated transmission zeros (TZs) and analysis are presented. A guidance is given for tuning the locations of TZs through parameter changes. Experimental results from the fabricated prototype validate the proposed design.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Engineering, Electrical & Electronic
Xiaoyu Weng, Kai-Da Xu, Haijun Fan
Summary: This brief presents a class of wideband bandpass filters (BPFs) using two eighth-mode substrate integrated waveguides (EMSIW) and two microstrip resonators. The design incorporates quarter-wavelength microstrip resonators to improve design flexibility and achieve a compact size. A BPF centered at 4 GHz with a fractional bandwidth (FBW) of 25% is designed and fabricated, demonstrating low insertion loss and high return loss. A transmission zero (TZ) is generated using mixed electric and magnetic coupling between two microstrip resonators to further enhance roll-off skirts and out-of-band rejection. The measured results validate the feasibility of the proposed BPFs.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Engineering, Electrical & Electronic
Zhong-Chao Lin, Yu Zhang, Liang Li, Yu-Tong Zhao, Jianzhong Chen, Kai-Da Xu
Summary: This article presents the design, principle, and characterization of a 3-D metamaterial absorber (MA) consisting of spatial lossy transmission lines (SLTLs) and resistively loaded high impedance surfaces (HIS). The MA has a fractional bandwidth of 193% and an absorption rate above 90% in the frequency range of 2 to 110 GHz under TM polarization, while maintaining a large oblique incident angle stability of over 50 degrees. The prototype's measurement results agree well with the simulation results. The proposed MA provides a general and systematic strategy for designing wideband absorbers with large incident angles.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Yiqun Liu, Kai-Da Xu
Summary: A novel on-chip dual-mode resonator (OCDMR) is proposed for the design of millimeter-wave (mm-wave) bandpass filters (BPFs). The proposed OCDMR consists of a stub-loaded metallic line and two identical open-end lines for coupling. The resonant frequencies of OCDMR can be adjusted by changing geometric parameters. Three different on-chip mm-wave BPFs with multiple transmission zeros (TZs) are designed and fabricated using the proposed OCDMRs, validating its feasibility for on-chip mm-wave BPF applications.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Puchu Li, Jian Ren, Yongji Chen, Xuenan Ren, Kai-Da Xu, Ying-Zeng Yin, Ming Shen
Summary: This article proposes a low-cost single-layer 2-bit programmable meta-surface (PM) that is processed on a single-layer printed circuit board (PCB). The PM utilizes a folded ground design to create space for bias lines and connect the top and bottom layers of the ground. It is capable of generating double beams, electromagnetic waves with orbital angular momentum (OAM), and a high-gain beam.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Qinlong Li, Dapeng Guo, Jianxing Li, Kai-Da Xu
Summary: A hybrid circuit combining spoof surface plasmon polaritons (SSPPs) and double-grating rectangular waveguide (DG-RWG) is proposed for designing a tunable bandwidth bandpass filter (BPF) operating at W-band. The dispersion curves of the SSPP-RWG and DG-RWG are analyzed, and the cut-off frequencies can be independently controlled by changing the geometric parameters. A W-band RWG BPF is designed and fabricated, with a measured bandwidth from 80.1 to 93.8 GHz and low insertion loss of about 0.57 dB at the center frequency.
IEEE MICROWAVE AND WIRELESS TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Kai-Da Xu, Xiaoyu Weng, Qiang Chen, Haijun Fan
Summary: This article presents a direct synthesis method for designing a wideband filtering switch by incorporating p-i-n diodes into each resonator. An ideal transformer is introduced in each resonator to provide freedom in selecting values for inductances and capacitances. A new circuit model extraction procedure is used to simplify the network topology, and the lumped circuit model is converted into a distributed circuit model to maintain the filtering response in a wide frequency range. The proposed method is validated through the fabrication and measurement of two filtering switches with different fractional bandwidths.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Gang Zhang, Xin Zhou, Kai-Da Xu, Jiquan Yang, Xiaohang Sun, Bin Xu, Kam-Weng Tam, Shuai Feng, Wanchun Tang, Jiasheng Hong
Summary: This article proposes a new design approach for filtering crossovers featuring wide-stopband and dual-band characteristics using mixed substrate integrated waveguide (SIW) cavities. The design utilizes the degenerate orthogonal modes in multimode full-mode SIW (FMSIW) square cavities to achieve cross-transmission and good isolation between dual channels. By developing coupling topology between multiple quarter-mode SIW (QMSIW) cavities and the FMSIW cavity, a compact wide-stopband filtering crossover is presented. Additionally, a dual-band filtering crossover is achieved by using half-mode SIW (HMSIW) cavities in conjunction with the FMSIW cavity.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Qinlong Li, Dapeng Guo, Jinchao Mou, Jianxing Li, Kai-Da Xu
Summary: In this article, a spoof surface plasmon polariton (SSPP) structure embedded in a groove gap waveguide (GGW) is proposed to realize an adjustable bandpass filter for Ka-band applications. By adjusting the groove width or pin height, the lower cut-off frequency of the passband can be tuned, while the upper cut-off frequency is determined by the SSPP unit cell's period or height through dispersion and S-parameter analysis. A fabricated GGW-SSPP bandpass filter demonstrates a measured bandwidth of 29.8 to 35.8 GHz, consistent with simulations. The proposed GGW-SSPP filter achieves adjustable bandpass characteristics with a low insertion loss of 0.22 dB thanks to the application of GGW.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Jianxing Li, Weiyu He, Kai-Da Xu, Juan Chen, Xiu Yin Zhang
Summary: This letter proposes a compact microstrip broadband filtering attenuator based on variable resistors with high-frequency selectivity. It can achieve tunable attenuation characteristics over a broad frequency band by changing the resistance of the variable resistors. The circuit structure is analyzed using odd- and even-mode methods. A fabricated prototype of the filtering attenuator operates from 1.3 to 2.8 GHz and realizes tunable attenuation from 3.26 to 15.61 dB. The results of theoretical calculations, simulations, and measurements agree well, validating the feasibility of the proposed design.
IEEE MICROWAVE AND WIRELESS TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Rui Hou, Tao Su, Jianzhong Chen, Kai-Da Xu
Summary: This article presents a synthesis and design method for a dual-band diplexer based on coaxial monoblock dielectric resonators (CMDRs) applied in the fifth-generation (5G) base stations. The comprehensive synthesis process, flexible CMDR bandpass filter (BPF) model, and a novel feeding structure for multiband CMDR filtering circuits are analyzed and introduced. An example of the dual-band CMDR diplexer is fabricated and measured, showing good performance.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
