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International Conference on Microwave and Millimeter Wave Technology Proceedings

作者： Ruikang Wang Bo Wu Meng Kong Jingyang Wang Yue Ma Xianliang Wu Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China Anhui Province Key Laboratory of simulation and design for Electronic information system Hefei Normal University Hefei China

ISBN: (纸本)9781665482271

In this paper, a 15 dB asymmetric broadband directional coupler for 4G and 5G communication is designed. The physical size of the coupler is $13\ \text{mm}\times 60\ \text{mm}$ . The dielectric constant is 4.4 and the thickness of single layer plate is 2 mm. The couplers operate in the 0.8-3.7 GHz band. The coupler has the advantages of bandwidth width, convenient processing and installation. ANSYS HFSS 2019 simulation results shows that in the 0.8-3.7 GHz band, the return loss (S 11 ) is more than 16.4 dB, the insertion loss (S 21 ) is from 0.14 dB to 1.18 dB, the coupling degree (S 31 ) is about 15 dB, and the isolation degree (S 41 ) is more than 29 dB. The method of multi-section coupling line cascade is adopted, to achieve the requirements of bandwidth width. The directivity of the coupler is increased by loading the branches to meet the design requirements of the 15 dB coupler.

关键词： Couplings Microwave technology Power transmission lines 5G mobile communication Simulation Millimeter wave technology Broadband communication

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Transient Electro-thermal Analysis of the Bipolar Transistor

Transient Electro-thermal Analysis of the Bipolar Transistor

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International Review of Progress in Applied Computational Electromagnetics (ACES)

作者： Hui Xiao Xingang Ren Yeqiang Yan Junjie Si Xueyuan Cai Bo Wu Zhixiang Huang Xianliang Wu Anhui Province Key Laboratory of Target Recognition and Feature Extraction Luan China Engineering Technology Research Center of Specific Power Devices with Novel Semiconductor Materials Chizhou Anhui Province China Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

This paper describes the transient electro-thermal properties of the bipolar transistor by a two-dimensional transient electro-thermal simulation, in which model the coupled heat conduction equation and drift-diffusion equations are solved. The backward difference scheme with the second-order accuracy was used to discretize the time derivative. The increment of bipolar transistor temperature will affect the drift and diffusion of carriers and thus its electrical characteristics. Through the transient study of electro-thermal characteristics of the bipolar transistor, the influence of the self-heating effect on bipolar transistor characteristic has considered in amplification mode. The developed model and results obtained in this work can be used to optimize the thermal design of bipolar transistor.

关键词： Performance evaluation Heating systems Bipolar transistors Temperature Electric variables Computational electromagnetics Mathematical models

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ExpTopo: Explicit Topological Modeling for Bronchus Segmentation

ExpTopo: Explicit Topological Modeling for Bronchus Segmenta...

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IEEE International Symposium on Biomedical Imaging

作者： Mingyue Zhao Xiaolan Qiu S.Kevin Zhou Division of Life Sciences and Medicine School of Biomedical Engineering University of Science and Technology of China (USTC) China Center for Medical Imaging Robotics Analytic Computing & Learning (MIRACLE) Suzhou Institute for Advance Research USTC China Suzhou Key Laboratory of Microwave Imaging Processing and Application Technology Suzhou Aerospace Information Research Institute China Key Laboratory of Precision and Intelligent Chemistry University of Science and Technology of China (USTC) China Key Laboratory of Intelligent Information Processing of Chinese Academy of Sciences (CAS) Institute of Computing Technology China

ISBN: (数字)9798331520526

ISBN: (纸本)9798331520533

Airway extraction is paramount in the early diagnosis and treatment of respiratory diseases. As a tree-like structure, both topological-aware learning and voxel-wise classification are equally crucial for the airway. However, existing methods demonstrate insufficient topological learning, emphasizing only the supervision of individual key topological points. Consequently, this paper proposes a Explicit Topological Modeling (ExpTopo) approach to aid airway segmentation. It explicitly introduces topological metric space learning based on semantic segmentation, enhancing the model's structural perception by implementing global skeleton-level sparse topological learning (STL) and local voxel-level dense topological perception (DTP). Extensive experimental results demonstrate that the algorithm achieves competitive performance at both the topological and voxel levels. Code will be available in https://***/MorineZ/ExpTopo.

关键词： Codes Atmospheric modeling Semantic segmentation Pulmonary diseases Biological system modeling Extraterrestrial measurements Biomedical imaging

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A Miniaturized Bandpass Filter Based on Hexagonal Resonator

A Miniaturized Bandpass Filter Based on Hexagonal Resonator

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Minquan Li Yajing Yan Ran Zhao Baokun Jin Man Zhang Guangxiu Zhao Xiaming Mo Ziyun Tu Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781665409889

This paper proposes a miniaturized bandpass filter (BPF) based on hexagonal resonator. Compared with the rectangular filter structure the hexagonal structure is compact, which can realize the miniaturization of the filter. The Y-shape branches are added to the three inner corners of the hexagon which are not adjacent to each other. At the same time, the input/output ports (I/O ports) position of is changed, two transmission zeros (TZs) are introduced at the high frequency band, and the size of the filter is reduced to achieve further miniaturization. In order to obtain better selectivity at low frequency, a split-ring resonator (SRR) is etched on the ground plane, and a TZ is introduced at low frequency. The simulation results show that the filter designed in this paper has a center frequency of 7.3 GHz along with a fractional bandwidth of 7.8%, which achieves a minimum insertion loss of 0.43 dB in the passband and a return loss better than 20 dB, three transmission zeros are introduced at 6.61 GHz, 8.06 GHz and 10.04 GHz, respectively. The final size of this filter is $0.23\lambda_{g}*0.29\lambda_{g}$, a reduction of 48.2%.

关键词： Band-pass filters Simulation Resonator filters Resonant frequency Insertion loss Propagation losses Filtering theory

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The Invention Relates to a Wideband Circularly Polarized Metasurface Antenna

The Invention Relates to a Wideband Circularly Polarized Met...

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Mengying Dong Xianliang Wu Yue Ma Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781665409889

Aiming at the single characteristic of traditional antenna bandwidth and working polarization state, a broadband circularly polarized antenna based on metamaterial surface is proposed. The antenna is composed of a rectangular microstrip antenna and an upper metasurface. The distance between the two is h. The metasurface is composed of $5\times 5$ square metal elements with equiangular structures on both sides. The linearly polarized rectangular microstrip antenna as the feeding antenna radiates linearly polarized electromagnetic waves, and the metasurface converts the linearly polarized electromagnetic waves radiated by the feeding antenna into circularly polarized electromagnetic waves. This paper analyzes the principle of circular polarization after the antenna is loaded with a metasurface. The simulation software HFSS is used to perform parameter scanning and simulation analysis on the antenna with the size of 0.88$\lambda\times 0.88$$\lambda\times 0.04$$\lambda \mathrm{m}^{3}$ and the center frequency of 8.5 GHz. The results show that the impedance bandwidth of the atenna S 11

关键词： Polarization Microstrip antennas Bandwidth Metasurfaces Antenna feeds Broadband antennas Microstrip

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Highly Selective UWB Bandpass Filter with Dual Notch Bands Using Stub Loaded Multiple-mode Resonator

Highly Selective UWB Bandpass Filter with Dual Notch Bands U...

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Guangxiu Zhao Minquan Li Ran Zhao Ziyun Tu Yajing Yan Xiaming Mo Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781665409889

In this paper, a low-loss ultra-wideband (UWB) bandpass filter with high selectivity and multiple notch bands is proposed. The filter is based on multi-mode resonator (MMR) which mainly consists of a step impedance transmission line that excites several resonant modes. The MMR structure is loaded a T-shaped open-circuited stub which generate two transmission zeros at the edge of the passband to improve selectivity. Meanwhile, MMR structure is also loaded two pairs of short high impedance stubs to extend the upper stopband of the filter. In addition, to address the in-band interference issues, by coupling a tunable parasitic unit to generate dual band notches at 5.8GHz (WLAN) and 8.1 GHz (X-band). Simulated result indicates that the designed filter’s passband is from 3.18 GHz to 10.67 GHz, the insertion loss is lower than 0.5 dB and its 3 dB relative bandwidth is 108.1%. At the same time, the filter has a high selectivity (30dB skirt factor is 0.917) and a stopband of up to 20 GHz (S 21 < −15dB).

关键词： Band-pass filters Couplings Wireless LAN Resonator filters Insertion loss Bandwidth Filtering theory

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Open-VCLIP: Transforming CLIP to an Open-vocabulary Video Model via Interpolated Weight Optimization

arXiv

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arXiv 2023年

作者： Weng, Zejia Yang, Xitong Li, Ang Wu, Zuxuan Jiang, Yu-Gang Shanghai Key Laboratory of Intelligent Information Processing School of Computer Science Fudan University China Shanghai Collaborative Innovation Center of Intelligent Visual Computing China Meta AI United States

Contrastive Language-Image Pretraining (CLIP) has demonstrated impressive zero-shot learning abilities for image understanding, yet limited effort has been made to investigate CLIP for zero-shot video recognition. We introduce Open-VCLIP, a simple yet effective approach that transforms CLIP into a strong zero-shot video classifier that can recognize unseen actions and events at test time. Our framework extends CLIP with minimal modifications to model spatial-temporal relationships in videos, making it a specialized video classifier, while striving for generalization. We formally show that training an Open-VCLIP is equivalent to continual learning with zero historical data. To address this problem, we propose Interpolated Weight Optimization, which utilizes the benefit of weight interpolation in both training and test time. We evaluate our method on three popular and challenging action recognition datasets following various zero-shot evaluation protocols and we demonstrate our approach outperforms state-of-the-art methods by clear margins. In particular, we achieve 87.9%, 58.3%, 81.1% zero-shot accuracy on UCF, HMDB and Kinetics-600 respectively, outperforming state-of-the-art methods by 8.3%, 7.8% and 12.2%. Code is released at https://***/wengzejia1/Open-VCLIP. Copyright © 2023, The Authors. All rights reserved.

关键词： Zero-shot learning

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A Novel Design of Wide Stopband Filter with High Selectivity

A Novel Design of Wide Stopband Filter with High Selectivity

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Minquan Li Xiaming Mo Ran Zhao Yajing Yan Guangxiu Zhao Ziyun Tu Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

ISBN: (纸本)9781665409889

In this paper, a wide stopband bandpass filter with high selectivity is designed, which uses three stepped impedance resonators to form the main body of the filter, which improves the stopband width of the filter, and has a wide stopband to 3f 0 . The parasitic passband of the filter is suppressed by etching the double T-shaped defected ground structure that changes the current distribution on the floor, generate a band gap with band-stop characteristics, the stopband width is over 4f 0 . Transmission zero is introduced by cross coupling resonance. There are two coupling paths for the signal from the input to output, one transmission zero is obtained on the upper stopband, then the selectivity of the filter is improved obviously. The simulation results show that the return loss of the filter can reach 46 dB and the insertion loss is less than 0.5 dB in the passband of 4.8 GHz-5.0 GHz. The stopband attenuation of 5.8 GHz-20 GHz is better than 20 dB. The rectangular coefficient of 30 dB/3dB is 3.72, and the size is 12 * 45.9 mm 2 .

关键词： Band-pass filters Couplings Photonic band gap Simulation Resonator filters Insertion loss Attenuation

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A Novel Broadband EBG Structure For Simultaneous Switching Noise Suppression

A Novel Broadband EBG Structure For Simultaneous Switching N...

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International Review of Progress in Applied Computational Electromagnetics (ACES)

作者： Guoxing Sun Yeqiang Yan Xingang Ren Xueyuan Cai Bo Wu Huping Ju Wei Tao Gang Wang Bao Zou Zhixiang Huang Xianliang Wu Anhui Province Key Laboratory of Target Recognition and Feature Extraction Luan China Engineering Technology Research Center of Specific Power Devices with Novel Semiconductor Materials Chizhou Anhui Province China Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

In this paper, a compact electromagnetic bandgap (EBG) structure for suppressing simultaneous switching noise (SSN) in high-speed circuits is proposed. At the bandwidth level of 0.35GHz to 20GHz, an ultra-wideband SSN suppression feature with a suppression depth of -40dB is achieved. The basic unit structure of the presented EBG is formed by etching an annular groove in the square patch and connecting the separated patches inside and outside the groove with a bridge adjacent to the end. An improved L-type bridge is used between the EBG units to further improve the EBG performance. Compared with the traditional L-type bridge, the suppression depth of the proposed electromagnetic bandgap structure is improved from -30dB to - 40dB. In addition, the time domain eye simulation results show that the structure has good signal integrity.

关键词： Bridge circuits Bandwidth Switches Tail Metamaterials Etching Time-domain analysis

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Nonreciprocity with Structured Light Using Optical Pumping in Hot Atoms

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Physical Review Applied 2022年第2期18卷 024027-024027页

作者： Fei Song Zhiping Wang Enze Li Benli Yu Zhixiang Huang Key Laboratory of Opto-Electronic Information Acquisition and Manipulation Ministry of Education Anhui University Hefei 230601 China and Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui University Hefei 230601 China Key Laboratory of Quantum Information University of Science and Technology of China Hefei Anhui 230026 China Key Laboratory of Intelligent Computing and Signal Processing Ministry of Education Anhui University Hefei 230039 China

Nonreciprocal transmission of structured light has possible applications in high-capacity optical communication and high-dimensional signal processing. Here, we demonstrate the magnet-free and cavity-free optical nonreciprocity of an orbital-angular-momentum (OAM) beam using optical-pumping technology with the assistance of the Doppler effect in hot atoms. By using optical pumping to induce a direction-dependent population transfer of the ground-state atoms, we realize optical nonreciprocity for the signal laser that is carrying OAM. Interestingly, an isolation ratio close to 30 dB and maximum transmission over 0.86 can be achieved simultaneously without the use of an optical cavity. Due to the unique amplitude and helical phase profile of the structured light, our proposal may open an avenue for exploring the singularity characteristics of optical nonreciprocity using structured light.

关键词： Angular momentum of light Light-matter interaction Non-reciprocal transmission Optical pumping Alkali metals Atomic gases Communication networks Devices

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