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- 实验方案
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Perfect metamaterial absorber with high fractional bandwidth for solar energy harvesting
摘要： A new perfect metamaterial absorber (PMA) with high fractional bandwidth (FBW) is examined and verified for solar energy harvesting. Solar cells based on perfect metamaterial give a chance to increase the efficiency of the system by intensifying the solar electromagnetic wave that incident on the device. The designed structure is mostly offered in the visible frequency range so as to exploit the solar’s energy efficiently. Parametric investigations with regard to the measurements of the design structure are fulfilled to characterize the absorber. The finite-difference time-domain (FDTD) method-based CST simulator was used to keep the pattern parameters and absorbance analysis. The metamaterial shows almost 99.96% and 99.60% perfect absorption at 523.84 THz and 674.12 THz resonance frequencies. Moreover, absorption’s FBW is studied, and 39.22% FBW is found. The results confirm that the designed PMA can attain very high absorption peak at two modes such as transverse electric (TE) and transverse magnetic (TM) mode. Other than the numerical outcomes demonstrated that the suggested configuration was also polarization angle insensitive. In addition, the change of absorbance of the structure has provided a new kind of sensor applications in these frequency ranges. Therefore, the suggested metamaterial absorber offers perfect absorption for visible frequency ranges and can be used for renewable solar energy harvesting applications.
关键词： solar energy harvesting,polarization angle insensitive,perfect metamaterial absorber,visible frequency range,high fractional bandwidth
更新于2025-09-23 15:21:21
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Sub-50 picosecond to microsecond carrier transport dynamics in pentacene thin films
摘要： Carrier transport dynamics from sub-50 ps to (cid:2)ls over five temporal decades in pentacene films was studied by transient photoconductivity. The behavior of the temperature independent photocurrent peak suggests that the photogenerated carriers exhibit pre-trapping transport in extended states upon pulsed laser excitation. From 300 ps to (cid:2)30 ns, the carriers thermalize and fall into shallow band tail states, and multiple-trapping and release transport dominates. From (cid:2)30 ns to (cid:2)ls, the weak temperature dependence of power-law photocurrent decay and the linear relation of logarithmic photocurrent with T(cid:3)1/4 suggest a variable range hopping transport in deep trap states.
关键词： transient photoconductivity,carrier transport dynamics,pentacene thin films,multiple-trapping and release transport,variable range hopping transport
更新于2025-09-23 15:21:21
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[IEEE 2019 IEEE 4th International Conference on Integrated Circuits and Microsystems (ICICM) - Beijing, China (2019.10.25-2019.10.27)] 2019 IEEE 4th International Conference on Integrated Circuits and Microsystems (ICICM) - A 71.8-87.9 GHz CMOS Injection-Locked Frequency Divider with Coupled Inductance
摘要： In this paper, a technique of inductor coupling is used to optimize the bandwidth of the injection-locked transformer. This design replaces the inductance of a conventional injection-locked divider with a transformer consists by two coupled inductance, each has its own independent cross-coupled pair. This design is based on 40nm- CMOS technology, with a supply voltage of 0.9V, the post- simulation results achieve a locking range of 71.8-87.9GHz with an injected signal of 0dBm, and the core chip size is 88×130μm2.
关键词： coupled,transformer,locking range,CMOS,injection-locked frequency divider (ILFD)
更新于2025-09-23 15:21:01
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[IEEE 2017 International Conference on Computer Technology, Electronics and Communication (ICCTEC) - Dalian, China (2017.12.19-2017.12.21)] 2017 International Conference on Computer Technology, Electronics and Communication (ICCTEC) - Three-Dimensional Pulse Electric Field Test System with Optical Fiber
摘要： A three-dimensional pulse electric field system with optical fiber is developed. It is made up of electric field testing probe, optical transmission system, optical receiver and display, which can realize three-dimensional pulse electric field measurement in the whole space. This paper introduced the three-Dreceiving antenna, the three-D electric field signal synthesis and photoelectric receiver and then analyzed the design of the three-D receiving antenna and the method of last, the three dimensional electric field synthesis. At performance of the testing system is measured. Results show that the system has good test performance whose bandwidth can reach 1KHz-1GHz, dynamic range can be up to 60dB.
关键词： dynamic range,bandwidth test,Pulse electric field,3-D electric field sensor
更新于2025-09-23 15:21:01
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Room Temperature Graphene Mid-Infrared Bolometer with a Broad Operational Wavelength Range
摘要： The last decade has witnessed the realization of numerous different types of graphene photodetectors with a strong focus on the visible and near-infrared spectral range, in which various high-performance photodetectors exist based on traditional materials such as silicon and III-V compound semiconductors. However, high-speed mid-infrared photodetection at room-temperature is still an unsolved challenge, despite its importance in applications such as security, sensing, and imaging. Here we address this challenge by demonstrating that high-quality graphene is an ideal high-speed bolometric material for the less-explored yet critical mid-infrared photodetection at room temperature, due to its broadband absorption, small heat capacity, and remarkably large temperature coefficient of resistance (TCR) of up to around 1% per Kelvin, which is comparable to that of commercial bolometric materials. We demonstrate a device based on graphene encapsulated in hexagonal boron nitride (hBN) exhibiting decent extrinsic responsivities of 5.1-1.4 mA/W in 3.4-12 μm wavelength range at room temperature, and further predict a detection bandwidth of at least 47 MHz. Our demonstration lays the foundations for graphene high-speed mid-infrared technologies.
关键词： high-quality graphene,broad wavelength range,scattering channels,Mid-infrared bolometer,temperature coefficient of resistance
更新于2025-09-23 15:21:01
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A simple extended-cavity diode laser using a precision mirror mount
摘要： We have developed an extended-cavity diode laser (ECDL) with a simple design by using a commercial precision mirror mount with minor modifications. Our design allows tuning of the external cavity configuration by tweaking the volume holographic grating without troublesome changes in the beam path of the laser output. The mode-hop-free tuning range of the presented ECDL is about 8 GHz with a linewidth of 475 kHz.
关键词： volume holographic grating,mode-hop-free tuning range,linewidth,extended-cavity diode laser,precision mirror mount
更新于2025-09-23 15:21:01
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Bayesian High Resolution Range Profile Reconstruction of High-Speed Moving Target From Under-Sampled Data
摘要： Obtained by wide band radar system, high resolution range profile (HRRP) is the projection of scatterers of target to the radar line-of-sight (LOS). HRRP reconstruction is unavoidable for inverse synthetic aperture radar (ISAR) imaging, and of particular usage for target recognition, especially in cases that the ISAR image of target is not able to be achieved. For the high-speed moving target, however, its HRRP is stretched by the high order phase error. To obtain well-focused HRRP, the phase error induced by target velocity should be compensated, utilizing either measured or estimated target velocity. Noting in case of under-sampled data, the traditional velocity estimation and HRRP reconstruction algorithms become invalid, a novel HRRP reconstruction of high-speed target for under-sampled data is proposed. The Laplacian scale mixture (LSM) is used as the sparse prior of HRRP, and the variational Bayesian inference is utilized to derive its posterior, so as to reconstruct it with high resolution from the under-sampled data. Additionally, during the reconstruction of HRRP, the target velocity is estimated via joint constraint of entropy minimization and sparseness of HRRP to compensate the high order phase error brought by the target velocity to concentrate HRRP. Experimental results based on both simulated and measured data validate the effectiveness of the proposed Bayesian HRRP reconstruction algorithm.
关键词： inverse synthetic aperture radar (ISAR) imaging,entropy minimization,Newton method,variational Bayesian inference,High resolution range profile (HRRP),under-sampled data,velocity estimation
更新于2025-09-23 15:21:01
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Mobile Robot Path Planning Using a Laser Range Finder for Environments with Transparent Obstacles
摘要： Environment maps must ?rst be generated to drive mobile robots automatically. Path planning is performed based on the information given in an environment map. Various types of sensors, such as ultrasonic and laser sensors, are used by mobile robots to acquire data on its surrounding environment. Among these, the laser sensor, which has the property of being able to go straight and high accuracy, is used most often. However, the beams from laser sensors are refracted and re?ected when it meets a transparent obstacle, thus generating noise. Therefore, in this paper, a state-of-the-art algorithm was proposed to detect transparent obstacles by analyzing the pattern of the re?ected noise generated when a laser meets a transparent obstacle. The experiment was carried out using the environment map generated by the aforementioned method and gave results demonstrating that the robot could avoid transparent obstacles while it was moving towards the destination.
关键词： re?ection noise,path planning,mobile robot,transparent obstacle recognition,laser range ?nder
更新于2025-09-23 15:21:01
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Experimental Demonstration of 3.9 mm Range Resolution Enabled by Synthetic Linearly Chirped THz Photonic Pulses
摘要： We experimentally demonstrate ultrahigh range resolution based on photonically generated linear frequency modulated (LFM) terahertz (THz) pulses. By synthesizing dual-band pulses in 315-360 GHz, a THz LFM signal with 40 GHz bandwidth and a time-bandwidth product (TBWP) of 336 is achieved, which successfully enables a range resolution as high as 3.9 mm over more than 4 m in multi-target ranging.
关键词： photonic generation,range resolution,terahertz,LFM pulses,synthetic technique
更新于2025-09-23 15:21:01
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[IEEE 2019 Twelfth International Conference on Mobile Computing and Ubiquitous Network (ICMU) - Kathmandu, Nepal (2019.11.4-2019.11.6)] 2019 Twelfth International Conference on Mobile Computing and Ubiquitous Network (ICMU) - Human Tracking of Single Laser Range Finder Using Features Extracted by Deep Learning
摘要： Human recognition using single laser range finder (LRF) is utilized for the task of following a target person such as a cargo transport robot. In these recognition methods, the approach is applied in which human-crafted features is inputted to the one-class classification model to identify whether it is a human or not. In this paper, we propose a method that introduce features extracted by deep learning. In this method, we create an encoder that can extract features from input data using PointNet-based autoencoder. In its experiment, the features extracted by encoder is compared with the human-crafted features, and these extraction process length of time is measured.
关键词： One-Class Classification,Point Cloud,Deep Learning,Laser Range Finder
更新于2025-09-23 15:21:01