In this paper,a hybrid integrated broadband Doherty power amplifier(DPA)based on a multi-chip module(MCM),whose active devices are fabricated using the gallium nitride(GaN)process and whose passive circuits are fabric...In this paper,a hybrid integrated broadband Doherty power amplifier(DPA)based on a multi-chip module(MCM),whose active devices are fabricated using the gallium nitride(GaN)process and whose passive circuits are fabricated using the gallium arsenide(GaAs)integrated passive device(IPD)process,is proposed for 5G massive multiple-input multiple-output(MIMO)application.An inverted DPA structure with a low-Q output network is proposed to achieve better bandwidth performance,and a single-driver architecture is adopted for a chip with high gain and small area.The proposed DPA has a bandwidth of 4.4-5.0 GHz that can achieve a saturation of more than 45.0 dBm.The gain compression from 37 dBm to saturation power is less than 4 dB,and the average power-added efficiency(PAE)is 36.3%with an 8.5 dB peak-to-average power ratio(PAPR)in 4.5-5.0 GHz.The measured adjacent channel power ratio(ACPR)is better than50 dBc after digital predistortion(DPD),exhibiting satisfactory linearity.展开更多
Using a fixed-point method, we establish the generalized Hyers-Ulam stability of a general mixed additive-cubic equation： f（kx ＋ y） ＋ f（kx - y） = kf（x ＋ y） ＋ kf（x - y） ＋ 2f（kx） - 2kf（x） in Banach mod...Using a fixed-point method, we establish the generalized Hyers-Ulam stability of a general mixed additive-cubic equation： f（kx ＋ y） ＋ f（kx - y） = kf（x ＋ y） ＋ kf（x - y） ＋ 2f（kx） - 2kf（x） in Banach modules over a unital Banach algebra.展开更多
Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induce...Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induced sidebands, which is based on the proper use of a continuous-wave and a pulse as light sources. We find that a mass of sidebands are generated in the modulation instability resonance region, and the power of the sideband increases with not only the peak power of the pump pulse but also the continuous-wave power which acts as a seed. The research will provide guidance for fiber communication and sensing systems using wavelength division multiplexing technology.展开更多
The layout of power modules is one of the key points in power module design,especially for silicon carbide module,which may parallel more devices compared with silicon counterpart.In this paper,along with the design e...The layout of power modules is one of the key points in power module design,especially for silicon carbide module,which may parallel more devices compared with silicon counterpart.In this paper,along with the design example,a improved layout design method for planar power modules is presented.Some practical considerations and implementations are also introduced in the optimization of module layout design.展开更多
Transparent liquid flattening or stretching realizes optical path length modulation. A flat thin seal transparent cavity, one flank is an electromagnetic driving membrane and is filled over with transparent liquid. Vi...Transparent liquid flattening or stretching realizes optical path length modulation. A flat thin seal transparent cavity, one flank is an electromagnetic driving membrane and is filled over with transparent liquid. Vibration of the membrane makes the liquid compressing or stretching, changes the liquid layer thickness, i.e. the optical path length of light through the liquid layer. The liquid layer compressed is equivalent to increase membrane tension. The membrane has higher resonant frequency. The cavity diameter 10 mm modulation frequency is about 18 kHz.展开更多
The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation res...The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.展开更多
A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese（Mn3＋, Mn4＋ and Mn5＋） can stably exist in the compound...A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese（Mn3＋, Mn4＋ and Mn5＋） can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction（XRD）, select area electron diffraction（SAED） and high resolution transmission electron microscopy（HR-TEM）. The splits of the diffraction peaks of the single crystals confirmed by synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3＋, Mn4＋ and Mn5＋ can be considered to be the dominating reason of the complicated room temperature modulated structure.展开更多
A simplified simulation method based on the FDTD technique that can handle active devices is proposed. This method well suits the electrical crosstalk analysis of multi-channel integrated, opto-electronic mixed module...A simplified simulation method based on the FDTD technique that can handle active devices is proposed. This method well suits the electrical crosstalk analysis of multi-channel integrated, opto-electronic mixed modules. We apply this method to an 8-channel integrated super-compact high-sensitivity optical module. The results show good agreement between simulations and measurements.展开更多
基于深度学习进行信号自动调制识别在分类精度、可迁移性等方面普遍优于传统方法,引起广泛关注。但是,当前方法多数针对单信号样本进行识别,无法适用于混叠信号识别场景。针对该问题,对混叠信号调制识别方法进行了研究,结合长短期记忆(l...基于深度学习进行信号自动调制识别在分类精度、可迁移性等方面普遍优于传统方法,引起广泛关注。但是,当前方法多数针对单信号样本进行识别,无法适用于混叠信号识别场景。针对该问题,对混叠信号调制识别方法进行了研究,结合长短期记忆(long short term memory,LSTM)网络和深度残差收缩网络(deep residual shrinkage network,DRSN),设计了时序深度残差收缩网络模型,其中包含残差模块、收缩模块和LSTM模块。残差模块和收缩模块负责提取混叠信号中的显著信息并自适应生成决策阈值,LSTM模块用于提取混叠信号中的时序隐含特征。三者结合可以有效提高混叠信号的识别精度。公开和实测数据集测试结果表明,所提方法识别精度优于5种典型方法,在高信噪比下的平均识别分类准确率可以达到92.7%;21种混叠信号中有12种识别准确率接近100%。展开更多
基金supported in part by the National Key Research and Development Program of China(2021YFA0716601)the National Science Fund(62225111).
文摘In this paper,a hybrid integrated broadband Doherty power amplifier(DPA)based on a multi-chip module(MCM),whose active devices are fabricated using the gallium nitride(GaN)process and whose passive circuits are fabricated using the gallium arsenide(GaAs)integrated passive device(IPD)process,is proposed for 5G massive multiple-input multiple-output(MIMO)application.An inverted DPA structure with a low-Q output network is proposed to achieve better bandwidth performance,and a single-driver architecture is adopted for a chip with high gain and small area.The proposed DPA has a bandwidth of 4.4-5.0 GHz that can achieve a saturation of more than 45.0 dBm.The gain compression from 37 dBm to saturation power is less than 4 dB,and the average power-added efficiency(PAE)is 36.3%with an 8.5 dB peak-to-average power ratio(PAPR)in 4.5-5.0 GHz.The measured adjacent channel power ratio(ACPR)is better than50 dBc after digital predistortion(DPD),exhibiting satisfactory linearity.
基金supported by the National Natural Science Foundation of China (10671013,60972089,11171022)
文摘Using a fixed-point method, we establish the generalized Hyers-Ulam stability of a general mixed additive-cubic equation： f（kx ＋ y） ＋ f（kx - y） = kf（x ＋ y） ＋ kf（x - y） ＋ 2f（kx） - 2kf（x） in Banach modules over a unital Banach algebra.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61177073)the Specialized Research Fundfor the Doctoral Program of Higher Education of China (Grant No.20104307110020)+1 种基金the Fund of Innovation of Graduate School of National University of Defense Technology, China (Grant No.B110703)the Hunan Provincial Innovation Foundation for Postgraduate, China (Grant No. CX2011B033)
文摘Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induced sidebands, which is based on the proper use of a continuous-wave and a pulse as light sources. We find that a mass of sidebands are generated in the modulation instability resonance region, and the power of the sideband increases with not only the peak power of the pump pulse but also the continuous-wave power which acts as a seed. The research will provide guidance for fiber communication and sensing systems using wavelength division multiplexing technology.
基金This work is supported by The National key research and development program of China(2016YFB0100600)the Key Program of Bureau of Frontier Sciences and Education,Chinese Academy of Sciences(QYZDBSSW-JSC044)the National Natural Science Foundation of China(No.51507166).
文摘The layout of power modules is one of the key points in power module design,especially for silicon carbide module,which may parallel more devices compared with silicon counterpart.In this paper,along with the design example,a improved layout design method for planar power modules is presented.Some practical considerations and implementations are also introduced in the optimization of module layout design.
文摘Transparent liquid flattening or stretching realizes optical path length modulation. A flat thin seal transparent cavity, one flank is an electromagnetic driving membrane and is filled over with transparent liquid. Vibration of the membrane makes the liquid compressing or stretching, changes the liquid layer thickness, i.e. the optical path length of light through the liquid layer. The liquid layer compressed is equivalent to increase membrane tension. The membrane has higher resonant frequency. The cavity diameter 10 mm modulation frequency is about 18 kHz.
基金Project supported by the National Natural Science Foundation of China （Grant No 60577033）, the Specialized Research Fund for the Doctoral Program of Higher Education （Grant No 20050003010） and the Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technology.
文摘The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.
基金Supported by the National Natural Science Foundation of China(No.90922034)
文摘A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese（Mn3＋, Mn4＋ and Mn5＋） can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction（XRD）, select area electron diffraction（SAED） and high resolution transmission electron microscopy（HR-TEM）. The splits of the diffraction peaks of the single crystals confirmed by synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3＋, Mn4＋ and Mn5＋ can be considered to be the dominating reason of the complicated room temperature modulated structure.
文摘A simplified simulation method based on the FDTD technique that can handle active devices is proposed. This method well suits the electrical crosstalk analysis of multi-channel integrated, opto-electronic mixed modules. We apply this method to an 8-channel integrated super-compact high-sensitivity optical module. The results show good agreement between simulations and measurements.
文摘基于深度学习进行信号自动调制识别在分类精度、可迁移性等方面普遍优于传统方法,引起广泛关注。但是,当前方法多数针对单信号样本进行识别,无法适用于混叠信号识别场景。针对该问题,对混叠信号调制识别方法进行了研究,结合长短期记忆(long short term memory,LSTM)网络和深度残差收缩网络(deep residual shrinkage network,DRSN),设计了时序深度残差收缩网络模型,其中包含残差模块、收缩模块和LSTM模块。残差模块和收缩模块负责提取混叠信号中的显著信息并自适应生成决策阈值,LSTM模块用于提取混叠信号中的时序隐含特征。三者结合可以有效提高混叠信号的识别精度。公开和实测数据集测试结果表明,所提方法识别精度优于5种典型方法,在高信噪比下的平均识别分类准确率可以达到92.7%;21种混叠信号中有12种识别准确率接近100%。
