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wide bandwidth ULTRASONIC TRANSDUCER DESIGN USING A LUMPED OSCILLATION COUPLED MODEL

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WIDE BANDWIDTH ULTRASONIC TRANSDUCER DESIGN USING A LUMPED O...

bandwidth improvement of high power uni-traveling-carrier photodiodes by reducing the series resistance and capacitance

2010全国压电和声波理论及器件技术研讨会

作者： Yeong-chin CHEN Menq-jion WU Department of Computer Science and Information Engineering Asia University Department of Mechatronics National Changhua University of Education

This paper will establish a closed-coupled oscillator model of the wide bandwidth ultrasonic transducer for ultrasound image *** to the acoustical impedance matching theorem,the bandwidth depend on different matching impedance of the matching layers is investigated,and then the wide bandwidth ultrasonic transducer can be *** order to shorten the pulse-echo duration time,the acoustical impedance of the backing layer is tuned to fit the resolution *** is implemented to model and simulate of the equivalent lumped circuit of the designed *** simulated results of transmitting transfer function and pulse-echo insertion loss can agree with the experimental *** the modeling accuracy is a bit less than that of propagation wave,this closed-coupled oscillator model seems relatively simple and easy to understand and closer to the original physical properties of elements of *** also provides a complete one-dimensional model for the transducer and can well describe the electromechanical characteristics of the transducer.

关键词： wide bandwidth ultrasonic transducer oscillation coupled impedance matching lumped circuit

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Chinese Physics B 2015年第7期24卷 601-605页

作者：李进熊兵孙长征罗毅王健郝智彪韩彦军汪莱李洪涛 Tsinghua National Laboratory for Information Science and Technology/State Key Laboratory on Integrated Optoelectronics Department of Electronic EngineeringTsinghua University

A backside illuminated mesa-structure In Ga As/In P modified uni-traveling-carrier photodiode（MUTC-PD） with wide bandwidth and high saturation power is fabricated and investigated. The device structure is optimized to reduce the capacitance and resistance. For the 22-μm-diameter device, the maximum responsivity at 1.55 μm is 0.5 A/W, and the 3-d B cutoff frequency reaches up to 28 GHz. The output photocurrent at the 1-d B compression point is measured to be 54 m A at 25 GHz, with a corresponding output radio frequency（RF） power of up to 15.5 d Bm. The saturation characteristics of the MUTC-PD are also verified by the electric field simulation, and electric field collapse is found to be the cause of the saturation phenomenon.

关键词： wide bandwidth high power uni-traveling-carrier photodiodes

A direct laser-synthesized magnetic metamaterial for low-frequency wideband passive microwave absorption

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International Journal of Extreme Manufacturing 2023年第3期5卷 667-680页

作者： Yihe Huang Yize Li Kewen Pan Yixian Fang Kai Chio Chan Xiaoyu Xiao Chao Wei Kostya S Novoselov John Gallop Ling Hao Zhu Liu Zhirun Hu Lin Li Laser Processing Research Centre Department of MechanicalAerospace and Civil EngineeringThe University of ManchesterOxford RoadM139PLManchesterUnited Kingdom Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201People’s Republic of China Department of Electrical and Electronics Engineering The University of ManchesterOxford RoadM139PL ManchesterUnited Kingdom National Physical Laboratory United Kingdom National Graphene Institute The University of ManchesterOxford RoadM139PL ManchesterUnited Kingdom Department of Materials The University of ManchesterOxford RoadM139PLManchesterUnited Kingdom Department of Physics and Astronomy The University of ManchesterOxfordRoadM139PL ManchesterUnited Kingdom Institute for Functional Intelligent Materials National University of Singapore117544 SingaporeSingapore Chongqing 2D Materials Institute Liangjiang NewAreaChongqing 400714People’s Republic of China

Microwave absorption in radar stealth technology is faced with challenges in terms of its effectiveness in low-frequency ***,we report a new laser-based method for producing an ultrawideband metamaterial-based microwave absorber with a highly uniform sheet resistance and negative magnetic permeability at resonant frequencies,which results in a wide bandwidth in the L-to *** of the electrical sheet resistance uniformity has been achieved with less than 5%deviation at 400Ωsq^(-1)and 6%deviation at 120Ωsq^(-1),resulting in a microwave absorption coefficient between 97.2%and 97.7%within a1.56–18.3 GHz bandwidth for incident angles of 0°–40°,and there is no need for providing energy or an electrical power source during the *** N-and S-doped turbostratic graphene 2D patterns with embedded magnetic nanoparticles were produced simultaneously on a polyethylene terephthalate substrate via laser direct *** proposed low-frequency,wideband,wide-incident-angle,and high-electromagnetic-absorption microwave absorber can potentially be used in aviation,electromagnetic interference(EMI)suppression,and 5G applications.

关键词： laser direct writing degrees of crystallization Fe_(3)O_(4)nanoparticles wide bandwidth low frequency

Nitrogen‑Doped Magnetic‑Dielectric‑Carbon Aerogel for High‑Efficiency Electromagnetic Wave Absorption

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Nano-Micro Letters 2024年第1期16卷 313-327页

作者： Shijie Wang Xue Zhang Shuyan Hao Jing Qiao Zhou Wang Lili Wu Jiurong Liu Fenglong Wang Key Laboratory for Liquid‑Solid Structural Evolution and Processing of Materials Ministry of Education Shandong UniversityJinan 250061People’s Republic of China School of Mechanical Engineering Shandong UniversityJinan 250061People’s Republic of China Shenzhen Research Institute of Shandong University Shenzhen 518057GuangdongPeople’s Republic of China

Carbonbased aerogels derived from biomass chitosan are encountering a flourishing moment in electromagnetic protection on account of lightweight,controllable fabrication and ***,developing a facile construction method of component design with carbon-based aerogels for high-efficiency electromagnetic wave absorption(EWA)materials with a broad effective absorption bandwidth(EAB)and strong absorption yet hits some ***,the nitrogen-doped magnetic-dielectric-carbon aerogel was obtained via ice template method followed by carbonization treatment,homogeneous and abundant nickel(Ni)and manganese oxide(MnO)particles in situ grew on the carbon *** to the optimization of impedance matching of dielectric/magnetic components to carbon aerogels,the nitrogen-doped magnetic-dielectric-carbon aerogel(Ni/MnO-CA)suggests a praiseworthy EWA performance,with an ultra-wide EAB of 7.36 GHz and a minimum reflection loss(RLmin)of−64.09 dB,while achieving a specific reflection loss of−253.32 dB mm−***,the aerogel reveals excellent radar stealth,infrared stealth,and thermal management ***,the high-performance,easy fabricated and multifunctional nickel/manganese oxide/carbon aerogels have broad application aspects for electromagnetic protection,electronic devices and aerospace.

关键词： Electromagnetic wave absorption wide bandwidth Dielectric-magnetic synergy Multifunction

Heterointerface engineering in hierarchical assembly of the Co/Co(OH)_(2)@carbon nanosheets composites for wideband microwave absorption

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Nano Research 2023年第2期16卷 2611-2621页

作者： Yuhan Wu Guodong Wang Xixi Yuan Gang Fang Peng Li Guangbin Ji College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Aerospace Research Institute of Material&Processing Technology Beijing 100076China

Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional ***,the mechanism of heterogeneous interfaces on microwave absorption is still *** this study,abundant heterointerfaces were customized in hierarchical structures via a collaborative strategy of lyophilization and hard *** impressive electromagnetic heterostructures and strong interfacial polarization were realized on the zero-dimensional(0D)hexagonal close-packed(hcp)-face-centered cubic(fcc)Co/two-dimensional(2D)Co(OH)_(2)nanosheets@three-dimensional(3D)porous carbon nanosheets(Co/Co(OH)_(2)@PCN).By controlling the carbonization temperature,the electromagnetic parameters were further adjusted to broaden the effective absorption bandwidth(EAB).Accordingly,the EAB of these absorbers were almost greater than 6 GHz(covering the entire Ku-band)in the thickness range of 2.0–2.2 mm except the sample *** far as to the S-0.8-700 achieved an EAB up to 7.1 GHz at 2.2 mm and the minimum reflection loss(RLmin)value was−25.8 ***,in the far-field condition,the radar cross section(RCS)of S-0.8-700 can be reduced to 19.6 dB·m^(2).We believe that this work will stimulate interest in interface engineering and provide a direction for achieving efficient absorbing materials.

关键词： microwave absorption wide bandwidth interface engineering hierarchical porous structure absorption mechanism

3D Printed Antennas for 5G Communication:Current Progress and Future Challenges

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Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers) 2023年第1期2卷 16-33页

作者： Yaru Wang Xueqin Zhang Ruyue Su Mingji Chen Chujing Shen Hao Xu Rujie He Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing100081China Suzhou Fanbo Additive Manufacturing Technology Co. Ltd.Suzhou215299China National Institute of Metrology Beijing100029China

With the advent of 5G and future trends for communication systems moving to millimeter wave(MMW)and higher frequencies,antennas will be required to have high gain,wide bandwidth,and low losses.3D printing realizes structures by sequential stacking layer-by-layer,which enables the manufacturing of antennas with ar-bitrary shapes in a cheaper,faster,and flexible *** study provides a review of current state-of-the-art 3D printed antennas for different ***,an overview of 3D printing technology is presented.A huge number of 3D printed antennas,categorized by their material composition,have been described,including poly-mer,metallic,ceramic,composite material,and multi-material integrated ***,the main challenges and prospects are discussed to provide insight into how 3D printing can be further progressed in antenna manu-facturing.

关键词： 3D printing Antennas,5G Millimeter wave High gain wide bandwidth

wide-Band Polarization-Independent Semiconductor Optical Amplifier Gate with Tensile-Strained Quasi-Bulk InGaAs

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Journal of Semiconductors 2004年第8期25卷 898-902页

作者：王书荣刘志宏王圩朱洪亮张瑞英丁颖赵玲娟周帆王鲁峰中国科学院半导体研究所光电子研发中心云南师范大学太阳能研究所昆明650092

A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is *** injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling ***,the most important is that very low polarization dependence of gain (50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm) and the whole L band (1570～1610nm).The gating time is also improved by decreasing carrier *** wide band polarization insensitive SOA gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.

关键词： semiconductor optical amplifier gate wide bandwidth polarization insensitive tensile strained quasi bulk InGaAs fiber to fiber lossless operation current extinction ratio