- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A 128-Pixel System-on-a-Chip for Real-Time Super-Resolution Terahertz Near-Field Imaging
摘要： This paper presents a fully integrated system-on-a-chip for real-time terahertz super-resolution near-field imaging. The chip consists of 128 sensing pixels with individual cross-bridged double 3-D split-ring resonators arranged in a 3.2 mm long 2 × 64 1-D array. It is implemented in 0.13-μm SiGe bipolar complementary metal–oxide–semiconductor technology and operated at around 550 GHz. All the functions, including sensor illumination, near-field sensing, and detection, are co-integrated with a readout integrated circuit for real-time image acquisition. The pixels exhibit a permittivity-based imaging contrast with a worst case estimated relative permittivity uncertainty of 0.33 and 10–12-μm spatial resolution. The sensor illumination is provided with on-chip oscillators feeding four-way equal power divider networks to enable an effective pixel pitch of 25 μm and a dense fill factor of 48% for the 1-D sensing area. The oscillators are equipped with electronic chopping to avoid 1/f-noise-related desensitization for the SiGe-heterojunction bipolar transistor power detectors integrated at each pixel. The chip features both an analog readout mode and a lock-in-amplifier-based digital readout mode. In the analog readout mode, the measured dynamic range (DR) is 63.8 dB for a 1-ms integration time at an external lock-in amplifier. The digital readout mode achieves a DR of 38.5 dB at 28 f/s. The chip consumes 37–104 mW of power and is packaged into a compact imaging module. This paper further demonstrates real-time acquisition of 2-D terahertz super-resolution images of a nickel mesh with 50-μm feature size, as well as a biometric human fingerprint.
关键词： terahertz,system-on-a-chip (SoC),SiGe heterojunction bipolar transistor (HBT),split-ring resonator (SRR),near-field array,3-push Colpitts oscillator,super-resolution imaging,near-field scanning optical microscopy (NSOM),power detector
更新于2025-09-09 09:28:46
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[IEEE 2018 Conference on Emerging Devices and Smart Systems (ICEDSS) - Tiruchengode, India (2018.3.2-2018.3.3)] 2018 Conference on Emerging Devices and Smart Systems (ICEDSS) - Comparison Studies of Planar and Bulk Hetero Junction Nano Photo Diodes using Carbon Nano Tube's (CNT) and Graphene for Sub-retinal implant
摘要： Age related Macula Degeneration (AMD) and Retinitis Pigmentosa (RP) are the two major diseases that that influence the elderly individuals broadly around the world. This paper aims to develop a simple device that helps the recovery of the vision. Nano Photo Diode Arrays (NPDA) are photovoltaic cells using nano-materials like CNT’s and Graphene. They can generate stimulating electrical pulses under incident light which stimulate the photoreceptor cells in the retina thus enabling the restoration of vision. In this work, the authors have attempted to compare the Bilayer or Planar hetero junction (PHJ) and Bulk Hetero Junction (BHJ) photodiodes and optimize that would form the NPDA for subretinal implants. The simulations are carried out to compare and study the PHJ and BHJ based nano photodiodes by varying the thickness of anode layer, active layer, and cathode layer.
关键词： PHJ,Photo diode,Nano Photodiode Array (NPDA),subretinal prostheses,BHJ
更新于2025-09-09 09:28:46
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The Polarimetric L-Band Imaging Synthetic Aperture Radar (PLIS): Description, Calibration, and Cross-Validation
摘要： The polarimetric L-band imaging synthetic aperture radar (PLIS) is a high spatial resolution (better than 6 m) airborne synthetic aperture radar system that has been dedicated to scientific research into civilian applications since 2010. The weight of PLIS is ～38 kg, allowing it to be installed aboard small low-cost aircraft, with two antennas used to measure the full backscatter matrix for a swath between 15° and 50° on each side of the flight direction. Calibration based on a total of 96 calibration points and a homogeneous forest during the two recent soil moisture active passive experiments (SMAPEx-4 and 5) showed an overall radiometric accuracy of 0.58 dB (root-mean-square error) over trihedral passive radar calibrators. Independent evaluation based on polarimetric active radar calibrators showed an amplitude imbalance of 0.17 dB with a standard deviation of 0.15 dB and a phase imbalance of 3.87° with a standard deviation of 2.86°. Two calibrated phased-array L-Band synthetic aperture radar-2 (PALSAR-2) images with different observation modes (ScanSAR and Stripmap) were compared with the calibrated PLIS images. The agreement between PALSAR-2 Stripmap and PLIS had a root mean square difference of 1.27 dB and a correlation coefficient of 0.87. Further comparisons over different landcover types confirmed that homogeneous forest and grassland areas constitute optimal targets for cross-validation and/or calibration.
关键词： Calibration and validation,phased-array L-Band synthetic aperture radar-2 (PALSAR-2),cross-calibration,synthetic aperture radar (SAR),polarimetric L-band imaging SAR (PLIS)
更新于2025-09-09 09:28:46
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Efficient Energy Management System for Solar Energy
摘要： Solar power is the major renewable energy source opted by developing countries as stand-alone/Grid enabled system. Industries and educational institutions are opting for solar energy to combat power crisis. This paper proposes knowledge based, self configurable, smart controller to efficiently use solar energy according to load, under frequent grid failure environment. It is enabled with fault identification and isolation. Extension to higher power capacity is easily achieved with plug and play mechanism. Proposed control architecture is implemented using Field Programmable Gate Array (FPGA), that supports modular level implementation with well defined interfaces for each sub-system. It can be used with low power as well as high power photo-voltaic system. Efficiency of the proposed architecture is demonstrated for the photo-voltaic system installed in educational institution.
关键词： Field Programmable Gate Array,Standalone system,Pulse width modulation,Photo-voltaic system
更新于2025-09-09 09:28:46
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[IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz2018) - Nagoya, Japan (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - A THz Imaging System Using Sparse Antenna Array for Security Screening
摘要： This paper presents our study on a THz imaging system using a sparse periodic linear antenna array (SPA) with large element spacing, consisting of only 14 transmitters and 16 receivers at 220GHz to achieve a horizontal field of view (FOV) of about 0.8m. The image of a realistic target scenario, i.e. the metallic objects concealed under a thin clothing in front of a human body phantom is reconstructed with data from an effective simulation based on a combined method between moment and ray launching-geometrical optics (RL-GO) algorithms in FEKOTM. The results have shown that a resolution of 3.5mm at 4m distance can be achieved in this THz imaging system. In addition, the study demonstrates compressive sensing (CS) reconstruction method is capable to provide a comparable image quality with a dramatic reduction of sampling data, which can also be applied in practical products to improve the imaging rate.
关键词： compressive sensing,THz imaging,security screening,sparse antenna array
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Symmetric Sparse Linear Array for Active Imaging
摘要： Sparse sensor arrays can achieve significantly more degrees of freedom than the number of elements by leveraging the co-array, a virtual structure that arises from the far field narrowband signal model. Although several sparse array configurations have been developed for passive sensing tasks, less attention has been paid to arrays suitable for active sensing. This paper presents a novel active sparse linear array, called the Interleaved Wichmann Array (IWA). The IWA only has a few closely spaced elements, which may make it more robust to mutual coupling effects. Closed-form expressions are provided for the key properties of the IWA. The parameters maximizing the array aperture for a given even number of elements are also found. The near field wideband performance of the array is demonstrated numerically in a coherent imaging scenario.
关键词： active sensing,Interleaved Wichmann Array,mutual coupling,Sparse sensor arrays,coherent imaging
更新于2025-09-09 09:28:46
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Optimizing electrospinning-hydrothermal hybrid process based on Taguchi method for modulation of point defects in ZnO micro/nano arrays towards photoelectronic application
摘要： Unlike previous work generally adopting high temperature annealing (≥500 ℃) to suppress defects in hydrothermal grown ZnO, this work suppressed ZnO defects by optimizing overall process parameters of low temperature electrospinning-hydrothermal hybrid process (≤300 ℃) with Taguchi method and Analysis of Variance (ANOVA). Sum ratio of defect peaks to eigen peaks (SRDE) in room-temperature photoluminescence (PL) spectrum was proposed to evaluate defect conditions in 27 experiments (L27 (38)). With the optimal process, good crystal quality (SRDE=0.31) was achieved at low temperature (200 ℃), of which the SRDE decreased by 68.04% compared with the initial counterpart. Then confirmation experiment was conducted to validate the selected levels, and results of signal-to-noise ratio (SNR) showed good agreement with the predicted ones. Besides, the response time and recovery time of the ZnO photodetectors with optimal process were decreased by 72.5% and 79.3%, respectively, compared with the initial ones. This method can also be used to fabricate ZnO materials with other wanted defect features.
关键词： Point defect,photodetector,ZnO micro/nano array,electrospinning-hydrothermal hybrid process,Taguchi method
更新于2025-09-09 09:28:46
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A Graphene-Coated Mo Tip Array for Highly-Efficient Nanostructured Electron Field Emitters
摘要： An ef?cient electron ?eld emitter based on a monolayer graphene coated well aligned Mo tip array has been designed, fabricated, and evaluated. The advantages of this hybrid nanostructure ?lm morphology are explored and discussed. Ef?cient and stable ?eld emissions with low turn-on ?elds have been observed with the new devices. It is further found that the combination of graphene and Mo tip array leads to signi?cant improvements in ef?ciency for the nanoscale heterostructure emitters.
关键词： molybdenum,tip array,?eld emission,graphene
更新于2025-09-09 09:28:46
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[IEEE 2018 Colour and Visual Computing Symposium (CVCS) - Gj?vik (2018.9.19-2018.9.20)] 2018 Colour and Visual Computing Symposium (CVCS) - Comparison of Mosaic Patterns for Spectral Filter Arrays
摘要： Spectral Filter Arrays allow snapshot multispectral acquisition within a compact camera. While Bayer ?lter mosaic is a widely accepted standard for color ?lter arrays, no single mosaic pattern is considered dominant for spectral ?lter arrays. We compare different patterns for 8-band mosaics, and their overall performance in terms of spectral reconstruction, as well as color and structure reproduction. We demonstrate that some mosaics having overrepresentation of certain ?lters perform better than the ones with overrepresentaiton of other ?lters, while the arrays having all ?lters equally represented perform better than the arrays with overrepresentation.
关键词： spectral imaging,SFA,?lter array,demosaicing,MSFA
更新于2025-09-09 09:28:46
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Low-loss Loaded Line Phase Shifter for Radar Application in X band
摘要： Losses in the phase shifters of phased arrays are one of the main limitations of these reconfigurable antennas. This contribution presents the design and measured results of variable phase shifters on triplicate suspended transmission lines in the microwave X-band for variable pointing radar applications. The antenna assembly remains passive and with a very low level of losses in the power distribution network and the phase shifters. PIN or varactor diodes are used to control the load on the transmission line. Each of these components has advantages and disadvantages that are discussed in the communication.
关键词： suspended strip,phase shifter,varactor,linear array,Pin diode
更新于2025-09-09 09:28:46