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[IEEE 2018 11th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP) - Budapest (2018.7.18-2018.7.20)] 2018 11th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP) - Multi point strain and temperature sensing based on Brillouin optical time domain reflectometry
摘要： In this paper, multiple points of strain and temperature measurement in real-time is investigated using a Brillouin optical time domain reflectometry (BOTDR) system. The Brillouin frequency shift (BFS) is analysed with strain and temperature effects applied at various locations of the sensing fibre. In addition, a passive depolarizer was employed in order to reduce the polarization noise. The strain and temperature coefficients are found to be 0.79 MHz/oC and 0.057 MHz/με.
关键词： Brillouin gain spectrum,strain measurement,temperature measurement
更新于2025-09-23 15:21:21
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[IEEE 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Singapore (2018.5.22-2018.5.25)] 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Solar Plant Integration to Utility Grid with Improved Power Quality by using RNN-Hebbian-LMS Current Controller
摘要： In this paper a new topology of current control technique is proposed, to transfer the improved quality of power produced from the solar plant to the utility grid. Also, a high-gain high-efficient converter driving with Kalman MPPT is used to boost the low voltage levels of the PV array. The proposed control uses recurrent neural network RNN-Hebbian -LMS based current controller to achieve the better performance in terms of power quality. The RNN network uses feedback signals to control the current flow from solar plant to the utility grid. The Hebbian - LMS (least mean square) algorithm is used to update the weights of the RNN based current controller. The main advantage of the RNN-Hebbian-LMS current control technique is to maintain the constant voltage. Besides, it also provides system stability over wide range of parameter variations and damp out the oscillations quickly. The proposed algorithm is able to overcome the stability and sensitivity problems incurred with the conventional PI current controller. The simulation results will be compared with the conventional PI and proposed RNN-Hebbiab-LMS current controllers. Finally, the proposed current controller shows the improved power quality, quick settling time and more stable comparing with the conventional controllers.
关键词： Least Mean Square (LMS),Utility Grid,Solar Plant,High-Gain converter,PV array,Maximum Power Point Tracking (MPPT),Recurrent Neural Network (RNN)
更新于2025-09-23 15:21:21
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Low-profile wideband Fabry-Perot resonator antenna using artificial magnetic conductor surface
摘要： A low-profile, high gain Fabry-Perot Resonator antenna with a wide operation bandwidth (BW) is presented in this paper. The proposed design consists of an ellipse-shaped dipole as a wideband radiating source, which is reflected by an artificial magnetic conductor ground plane to achieve low-profile structure. The antenna gain can be significantly enhanced by the use of a half-wavelength-thick dielectric slab as a partial reflecting surface. Additionally, this dielectric slab also contributes to improving the radiation pattern characteristics of the proposed design, especially in the high frequency region. A final prototype with an overall size of 1.2λL × 1.2λL × 0.4λL (λL is free-space wavelength at the lowest frequency of 3-dB gain BW) has been fabricated to validate the concept. The measured results show that the proposed antenna yielded a wide 3-dB gain BW of approximately 50.3% with a peak gain of 14 dBi and impedance matching BW of 48.9%.
关键词： high gain,wideband,artificial magnetic conductor,half-wavelength dielectric slab,Fabry-Perot antenna,low profile
更新于2025-09-23 15:21:21
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[Springer Tracts in Modern Physics] Parity-time Symmetry and Its Applications Volume 280 || Parity-Time-Symmetric Optical Lattices in Atomic Configurations
摘要： In this chapter, we show how to theoretically design and experimentally construct exact parity-time (PT) symmetric optical lattices with gain and loss in atomic configurations. By making use of the advantages of light-induced atomic coherence in multi-level atomic systems, spatially extended gain and loss arrays with real-time reconfigurability and multiple-parameter tunability can be effectively obtained in hot atomic vapors. We have constructed periodically alternative gain-loss structures with two very different schemes based on spatially-arranged optical induction techniques. With the required symmetric/antisymmetric spatial distributions for the real/imaginary parts of the refraction index satisfied, PT-symmetric optical lattices can be achieved with easy controllability. The dynamic behaviors of light propagating inside the induced non-Hermitian optical lattices are investigated by measuring the relative phase difference between two adjacent gain and loss channels.
关键词： Light-Induced Atomic Coherence,Non-Hermitian Optical Lattices,Atomic Configurations,Parity-Time-Symmetric Optical Lattices,Gain and Loss
更新于2025-09-23 15:21:21
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - General Conditions to Realize Exceptional Points of Degeneracy and Applications
摘要： We explore the emergence of exceptional points of degeneracy (EPDs) that denote a coalescence of multiple eigenmodes in coupled-mode structures. We establish the general conditions that lead to observing EPDs of different orders in various coupled systems, either uniform (non-periodic) or periodic. EPDs can be found in lossless systems as well as in systems with gain-loss balance. Also, we provide examples of potential applications of structures with EPDs that help improve the performance of devices, like sensors, oscillators, etc., at microwave and optical frequencies.
关键词： exceptional points of degeneracy,optical frequencies,microwave frequencies,EPDs,gain-loss balance,oscillators,lossless systems,coupled-mode structures,sensors
更新于2025-09-23 15:21:21
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Analog and RF assessment of sub-20?nm 4H-SiC trench gate MOSFET for high frequency applications
摘要： In this work, 4H-SiC Trench Gate (Recessed Channel) (4H-SiC-RC) MOSFET structure is demonstrated to have superior analog and RF Figure of Merits (FOMs) by numerical simulation. The integration of 4H-SiC with phosphorene contact on to the trench region results in higher drain current (2.3 mA) and outstanding switching ratio (1016) owing to reduced off-current which leads to the lower sub-threshold slope (SS). Other electrical parameters such as electric ?eld, electron mobility, and electron velocity are remarkably improved in 4H-SiC-RC MOSFET. Further, the high-frequency RF FOMs have also been studied, and it is observed that cut-off frequency (fT) gets doubled and maximum oscillator frequency (fMAX) increased by ?ve times in the proposed design as compared to conventional design. Thus, the 4H-SiC-RC design is suitable for high switching, high power, and high-frequency application.
关键词： Gain,RF,4H-SiC-RC-MOSFET,Stray capacitance,Analog,Frequency
更新于2025-09-23 15:21:21
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Broadband Antennas with Reactive Loads
摘要： The results of a study on the expansion of the frequency range of vibrational curved whip and loop antennas are presented. Optimal designs of these antennas with concentrated reactive loads included in the shoulders are proposed. The study was carried out for a design that appears promising for use as a microstrip antenna. It is a Z-shaped antenna of orthogonal linear polarization and loop antenna, supplemented by concentrated capacitive loads. It is shown that in order to obtain in the Z-shaped antenna and loop antenna a regime of a current close to the traveling wave regime and to obtain broadband, it is sufficient to include no more than four capacitive loads of a certain value in the antenna arm. This makes the construction of a broadband antenna and to reduce the expenditure of time and resources for its development and fabrication in comparison with known works in which it was proposed to include in the arm of the antenna a much larger number of reactive loads.
关键词： concentrated capacitive load,distribution of the complex current at the antenna,broadband antenna,standing wave voltage factor,antenna gain factor
更新于2025-09-23 15:21:21
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Method of Detection of Thermal Microwave Radiation Increments
摘要： The optimal method for detecting objects of microwave radiation in a Ratio-type radiometer with an unstable receiver gain is synthesized. Analysis of the method indicates that the measurement results are not shifted, and the method itself can be practically implemented. The analytical expressions of the probabilistic and energy characteristics of objects detection against the background of the sky at various signal-to-noise conditions are obtained. The technical implementation of the detection method is proposed and experimental research is carried out.
关键词： Ratio-type microwave radiometer,unstable gain,Radar detection
更新于2025-09-23 15:21:21
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A Synthesizable Constant Tuning Gain Technique for Wideband LC-VCO Design
摘要： In this paper, an iterative method is proposed for the optimization of wideband voltage-controlled oscillators (VCOs). The proposed method attempts to improve two significant performance metrics of wideband VCOs, i.e., the non-uniform band distribution and the non-constant tuning gain KVCO. To address these non-ideality issues, we introduce the deviation as a prior knowledge for calibration in each iteration step. The optimal capacitor array weighting plan can be asymptotically approached through multiple iterations. To demonstrate the efficacy of the proposed method, we use it to implement a 1-to-2.4-GHz LC-VCO and achieve a frequency tuning range of 82.4%. The optimized LC-tank involves 64 mixed cells, and each cell contains 2-bit binary-weighted switching capacitors, leading to 256 tuning bands. The LC-VCO with the synthesized tank achieves uniform frequency steps around 5 MHz with the relative error within ±4.4%. Meanwhile, the tuning gain KVCO is around 10 MHz/V with the relative error within ±3.2%. For this LC-VCO design, each iteration step costs about 55.9 s. After 7 iterations, we approach the convergent solution where both the relative errors of the frequency steps and the tuning gains satisfy the given specifications.
关键词： Constant tuning gain,Constant frequency step,Automatic synthesis,Iteration,Wideband voltage-controlled oscillator (VCO)
更新于2025-09-23 15:21:21
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Optimization of Temperature Dependence of Heteronanolaser Threshold Current with Account for the Thickness and Dielectric Properties of the Heterostructure Waveguide Nano-Layer Material
摘要： An exact problem of the electromagnetic wave propagation in a multilayer heteronanostructure with complex values of the dielectric constant (permittivity) is solved. The contribution to the refractive index of an additive to the dielectric constant due to the injected carriers is taken into account. A heterostructure based on a nanosystem used for the manufacture of lasers in the range 0.94–1.14 μm is considered. The methods and approaches used are also applicable for optimizing multilayer structures based on other solid solutions and those with several quantum wells. Based on the calculations of the temperature dependence of the radiation characteristics of injection lasers based on heteronanostructures, it was shown that the anomalous behavior of the temperature dependence of the threshold current is associated with a weakening of the waveguide properties of their active region. In accordance with the calculation results, the heteronanotructures parameters of injection lasers were optimized with respect to the thickness and dielectric properties of the waveguide nanolayer material, which made it possible to significantly reduce the temperature dependence of their radiative characteristics.
关键词： solid solution,threshold current,optimization of the heterostructure parameters,local gain,mode gain,injection lasers,optical waveguide,heteronanostructure,quantum-well heterostructures
更新于2025-09-23 15:21:01