- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Fabrication of FP-cavity-based monolithic full-color filter arrays using a template-confined micro-reflow process
摘要： Fabry-Perot (FP) resonators are of great interest for various applications due to their high stability, environmental friendliness and chemical inertia. However, it is still technically challenging to obtain compact monolithic MDM-based color filter array (CFA) because of the difficulty in achieving microscale-pixelated stepwise dielectric films with designed thickness. In this work, we proposed a template-confined thermal reflow approach to fabricate monolithic CFA based on silver-polymethyl methacrylate-silver (Ag-PMMA-Ag) sandwich configuration. Via template-confined thermal reflow of periodic PMMA nanogratings with different filling density, the thickness of PMMA dielectric layer in each pixel can be independently controlled, enabling the spectral tunability across the whole visible light region with high transmission efficiency and narrow linewidth. Compared to conventional multiple deposition technique, the approach we proposed is able to control the thickness of dielectric film via a single exposure step and can be potentially applied in high-throughput production by combining nanoimprint lithography.
关键词： micro-reflow,monolithic stepwise dielectric layer,PMMA,color filter array,Fabry-Perot resonator
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Communications (ICC 2018) - Kansas City, MO (2018.5.20-2018.5.24)] 2018 IEEE International Conference on Communications (ICC) - Beamspace Channel Estimation for Wideband Millimeter-Wave MIMO with Lens Antenna Array
摘要： Beamspace channel estimation is essential for wideband millimeter-wave (mmWave) MIMO with lens antenna array to achieve the substantial increase in data rates, but with a considerably reduced number of radio-frequency chains. However, most of existing beamspace channel estimation schemes are designed for narrowband mmWave systems, while a very few wideband schemes assume that the beamspace channel enjoys the ideal common support in frequency domain. In this paper, inspired by the classical successive interference cancellation for multi-user detection, we propose an efficient successive support detection (SSD) based beamspace channel estimation scheme without the assumption of common support. Specifically, we first demonstrate that each path component of the wideband beamspace channel exhibits a unique frequency-varying sparse structure. Based on this, we then estimate all sparse path components one by one. For each path component, its supports at different frequencies are jointly estimated to improve the estimation accuracy, and then its influence is removed to estimate the remained path components. Once all path components have been estimated, the wideband beamspace channel can be recovered at a low complexity. Simulation results verify that the proposed SSD based beamspace channel estimation scheme is able to achieve higher accuracy than existing wideband schemes.
关键词： beamspace channel estimation,wideband millimeter-wave MIMO,frequency-varying sparse structure,successive support detection,lens antenna array
更新于2025-09-04 15:30:14
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[IEEE 2018 7th International Conference on Computer and Communication Engineering (ICCCE) - Kuala Lumpur, Malaysia (2018.9.19-2018.9.20)] 2018 7th International Conference on Computer and Communication Engineering (ICCCE) - The 2 <sup>*</sup> 1 Microstrip Antenna Array with Low Coupling using Periodic Paperclip-shaped Slots
摘要： The periodic paperclip-shaped (PPS) structure has been employed to suppress strong mutual coupling between antenna elements for microstrip antenna array in MIMO wireless communication system. The special decoupling structure consists of three paperclip-shaped units periodically placed at the centre of the two narrow patches with the adjacent patches spacing of 0.1λ (λ free space frequency), providing the bandstop characteristic to keep out the strong mutual coupling between antenna elements. By using the proposed special bandgap structure, more than 36 dB mutual coupling reduction between microstrip antenna elements is achieved at the centre frequency 5.0 GHz without any resonant frequency shift. Note that inserting periodic paperclip-shaped structure could concentrate on strong power towards the particular side by changing current distribution and propagation direction, so the slight gain enhancement has been obtained by comparing to the antenna array without PPS structure. Additionally, this PPS structure is also suitable for antenna array with other frequency by adjusting size of the PPS structure.
关键词： periodic paperclip-shaped structure,antenna array,mutual coupling reduction
更新于2025-09-04 15:30:14
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - A Functional Framework for Ultrasound Imaging
摘要： Delay-And-Sum (DAS), the state-of-art in ultrasound imaging, is known to be sub-optimal, resulting in low resolution and contrast. Most proposed improvements involve ad-hoc re-weighting, or hit computational bottlenecks given real-time requirements. This paper takes a fresh perspective on the problem, leveraging a functional framework to obtain a regularized least-squares estimate of the tissue reflectivity function. An explicit solution is derived, which – for specific cases – can be efficiently implemented, making it suitable for real-time imaging. In our formulation, DAS appears as a back-projection without any optimal properties. We illustrate the framework through first a one-dimensional set-up, and then a two-dimensional extension with Synthetic Aperture Focusing Technique (SAFT). The one-dimensional simulations show a 77% resolution improvement with respect to DAS, which artificially limits the available bandwidth. On a standard performance-assessment phantom, simulations show that SAFT depth resolution can be improved by 71%.
关键词： Sampling Operator,Ultrasound,Array Signal Processing,Pulse Compression,Inverse Problem
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Hybrid 12-Antenna Array for Quad-Band 5G/Sub-6GHz MIMO in Micro Wireless Access Points
摘要： In this paper, a 12-port 5G multiple-input multiple-output (MIMO) antenna array for micro wireless access points is studied. By integrating four F-shaped open slot antennas and eight F-shaped electric antennas, the proposed antenna array supports 4 × 4 MIMO in the LTE bands 42/43 (3.4–3.8 GHz), and 8 × 8 MIMO in the 4.9-GHz band/LTE band 46 (4.8–5.925 GHz). In the operation bandwidth, high total efficiency (> 70%), apparent radiation diversity characteristic and low envelope correlation coefficient (ECC, < 0.01) are obtained.
关键词： sub-6GHz,LTE bands,antenna array,5G,MIMO
更新于2025-09-04 15:30:14
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EFFICIENT LOCALIZATION ALGORITHM OF MIXED FAR-FIELD AND NEAR-FIELD SOURCES USING UNIFORM CIRCULAR ARRAY
摘要： An e?cient algorithm based on high-order cumulant is addressed for the scenarios where both far-?eld and near-?eld narrow-band signals may exist synchronously. The ?rst matrix built by four-order cumulant is utilized to estimate the two dimensional direction-of-arrivals (DOAs) using the orthogonal projection matrix of the signal subspace and the virtual steering matrix. Then, the second matrix built by four-order cumulant is decomposed to get the noise subspace using the eigen decomposition. Meanwhile, a virtual steering matrix is used to distinguish far-?eld signals (FFSs) from near-?eld signals (NFSs). And one-dimensional MUSIC algorithm is used to estimate the range of the NFSs. Compared to the TSMUSIC, the proposed algorithm can provide high resolution for the DOAs. In addition, there is higher accuracy for the DOA of NFS in the proposed algorithm than that in TSMUSIC and in TSMD. Simulation results are carried out to certify the performance of the proposed algorithm.
关键词： near-field signals,MUSIC algorithm,high-order cumulant,uniform circular array,far-field signals,DOA estimation
更新于2025-09-04 15:30:14
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InAs/InAsSb Type-II Superlattice Mid-Wavelength Infrared Focal Plane Array With Significantly Higher Operating Temperature Than InSb
摘要： We report focal plane array (FPA) results on a mid-wavelength InAs/InAsSb type-II strained layer superlattice (T2SLS) unipolar barrier infrared detector with a cutoff wavelength of 5.4 μm. For 300 K background in the 3–5-μm band, f/2 aperture, an FPA operating at 150 K exhibits a mean noise equivalent differential temperature (NEDT) of 18.5 mK, and an NEDT operability of 99.7%. The NE(cid:2)T distribution has a width of 8 mK, with no noticeable distribution tail, indicating excellent uniformity. The mean noise-equivalent irradiance is 9.1 × 1011 photons/sec-cm2. The mean quantum ef?ciency is 49.1% without antire?ection coating, and the mean speci?c detectivity (D?) is 2.53 × 1011 cm-Hz?/W. Bene?tting from an absorber material with a much longer Shockley–Read–Hall minority carrier lifetime, and a device architecture that suppresses generation-recombination and surface-leakage dark current, the InAs/InAsSb T2SLS barrier infrared detector FPA has demonstrated a signi?cantly higher operating temperature than the mid-wavelength infrared market-leading InSb.
关键词： Infrared detector,heterostructure,InAs/InAsSb,type-II superlattice,photodetector,nBn,unipolar barrier,focal plane array
更新于2025-09-04 15:30:14
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Reduced Current Sensor Based Solar PV Fed Motion Sensorless Induction Motor Drive for Water Pumping
摘要： This paper proposes a solar photovoltaic (PV) array fed induction motor (IM) drive operated water pumping system with an speed adaptive estimator. It focuses on the implementation of a space vector modulation (SVM) of voltage source inverter (VSI) without current sensors. The motor phase currents are estimated from the DC link current. The VSI is used for maximum power tracking and to drive an IM. A generalized integrator based flux adaptation approach is used to improve the drive performance. Moreover, a modified model reference adaptive system (MRAS) based speed estimation with rotor fluxes and stationary frame currents enhances its stability throughout the operating range. A modified algorithm based on incremental-conductance (InC) is proposed for maximum power point (MPP), which is used for peak power tracking at each insolation with a technique to control flow-rate. The overall system incorporating a single-stage PV powered space vector modulation (SVM) based VSI fed IM driven water pump is modeled and its performance is simulated in MATLAB/Simulink environment. The appropriateness of proposed system is verified experimentally on a prototype developed in the laboratory under various operating conditions.
关键词： Incremental-conductance (InC) algorithm,Speed adaptation,PV array,Induction motor drive (IMD),Water pump,Current sensor reduction,Field-oriented control (FOC)
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Microstrip patch antenna arrays with fan-shaped 90 and 45-degree wide radiation patterns for 28 GHz MIMO applications
摘要： The paper describes two microstrip antennas realized on Rogers RT/Duroid 5880 substrate and operating in the 28 GHz band attracting a lot of attention recent years. The antennas are both have fan-shaped radiation patterns effective for covering wide angle sectors by communication base stations either in indoor or outdoor scenarios. The narrow pattern (4.5 degree) in elevation provides high antenna gain of 17 dBi (90-degree sector) and 19 dBi (45-degree sector) ensuring high communication distance. Each designed antenna includes two patch arrays with orthogonal vertical and horizontal polarizations. Special techniques were implemented to achieve the isolation between the two arrays of each antenna as high as 40 dB that allows supporting MIMO operation with high modulation order. Both antennas are simulated in CST Microwave Studio and accurately measured. Measurement results confirmed high antenna performance that makes it perspective for practical use in various communication devices.
关键词： antenna array,fan-shaped radiation pattern,microstrip patch,MIMO
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Hangzhou, China (2018.8.13-2018.8.17)] 2018 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Precisely Lateral Alignment of Gold Nanorods Array via Hydrophilic-Hydrophobic Pattern
摘要： A simple strategy which combines the controlled solvent evaporation and hydrophilic-hydrophobic pattern to allow assembling gold nanorods (GNRs) on a flat substrate with arbitrary shapes in this work. Soft polydimethylsiloxane (PDMS) template as a pattern transfer stamp were utilized and transferred the structures onto the substrate successfully. By tuning the structures and sizes of templates, oriented large area lateral aligned GNRs arrays were fabricated as expected. Scan electron microscopy (SEM) images revealed that GNRs had been precisely placed as expected and the assembly is uniform.
关键词： hydrophilic-hydrophobic pattern,gold nanorods,self-assembly,solvent evaporation,micro-array
更新于2025-09-04 15:30:14