- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Minimal Timing Jitter in Superconducting Nanowire Single-Photon Petectors
摘要： Using a two-temperature model coupled with the modified time-dependent Ginzburg-Landau equation, we calculate the delay time τd in the appearance of a growing normal domain in the current-biased superconducting strip after absorption of the single photon. We demonstrate that τd depends on the place in the strip where the photon is absorbed and monotonically decreases with an increasing current. We argue that the variation of τd (timing jitter), connected either with position-dependent response or Fano fluctuations, could be as small as the lowest relaxation time of the superconducting order parameter, approximately ?/kBTc (Tc is the critical temperature of the superconductor), when the current approaches the depairing current.
关键词： position-dependent response,timing jitter,superconducting nanowire single-photon detectors,delay time,Fano fluctuations
更新于2025-09-23 15:23:52
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Investigation of RF and DC Performance of E-Mode In <sub/>0.80</sub> Ga <sub/>0.20</sub> As/InAs/In <sub/>0.80</sub> Ga <sub/>0.20</sub> as Channel based DG-HEMTs for Future Submillimetre Wave and THz Applications
摘要： In this paper, we systematically investigated the DC and RF behaviour of the novel Enhancement-Mode (E-Mode) Double-Gate High Electron Mobility Transistors (DGHEMTs) using Sentaurus-TCAD software. The scalability of the novel DGHEMT is also studied by analysing the short channel effects. The attractive features of the proposed DGHEMT are intrinsic In0.80Ga0.20As/InAs/In0.80Ga0.20As channel, dual silicon delta doping sheets and platinum (Pt) buried gate technology. The proposed DGHEMT with Lg = 20 nm exhibits a gm_max of 3970 mS/mm and IDS_max of 1650 mA/mm at VGS = 0.6 V and VDS = 0.8 V. The proposed DGHEMT exhibits a threshold voltage of 20 mV which indicates its E-Mode behaviour. The sub-threshold swing (SS) and DIBL values obtained for Lg = 20 nm DGHEMT at VDS = 0.5 V are 74 mV/dec and 78 mV/V respectively. The Lg = 20 nm proposed E-Mode DGHEMT also exhibit a fT and fmax of 826 and 1615 GHz respectively at VDS = 0.6 V. The computed logic gate delay for the Lg = 20 nm DGHEMT is 31.25 fS with an electron velocity under the gate of 6.4 × 107 cm/S. This excellent RF and DC behaviour of the proposed DGHEMT makes them an excellent choice for future sub-millimetre wave and THz frequency applications.
关键词： quantum well (QW),InAs,Drain induced barrier lowering (DIBL),short channel effects (SCEs),gate delay,sub-threshold swing (SS)
更新于2025-09-23 15:23:52
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Dynamic Behavioral Modeling of RF Power Amplifier Based on Time-Delay Support Vector Regression
摘要： A new, dynamic behavioral modeling technique, based on a time-delay support vector regression (SVR) method, is presented in this paper. As an advanced machine learning algorithm, the SVR method provides an effective option for behavioral modeling of radio frequency (RF) power amplifiers (PAs), taking into account the effects of both device nonlinearity and memory. The basic theory of the proposed modeling technique is given, along with a detailed model extraction procedure. Unlike traditional artificial neural network (ANN) techniques, which take time to determine the best configuration of the model, the SVR method can obtain the optimal model in short time, using the grid-search technique. An example of an optimal SVR model selection applied to an RF PA is also given; the performance of the selected model presents a big improvement when compared with the default SVR model. Experimental validation is performed using an LDMOS PA, a single device gallium nitride (GaN) PA, and a Doherty GaN PA, revealing that the new modeling methodology provides very efficient and extremely accurate prediction. Compared with traditional Volterra models, canonical piecewise linear models, and ANN-based models, the proposed SVR model gives improved performance with reasonable complexity. In addition, it is shown that the model can predict accurately the behavior of the PA under input power levels that are different from those under which it is extracted.
关键词： time delay,radio frequency (RF) power amplifiers (PAs),machine learning,Dynamic behavioral model,support vector regression (SVR)
更新于2025-09-23 15:23:52
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Influence of Current Density on Orientation-Controllable Growth and Characteristics of Electrochemically Deposited Au Films
摘要： This paper is concerned with the stability analysis of time varying delayed stochastic Hopfield neural networks in numerical simulation. To achieve our expected conclusions, we will reform the classical contractive mapping principle in functional analysis, with some modifications, to adapt to our conditions and both the continuous and the discrete delayed models. Under the reasonable conditions, it is shown that, the Euler–Maruyama numerical scheme is mean square exponentially stable of exact solution dependent of step size. Further more, it is also shown that the backward Euler–Maruyama numerical scheme can share the mean square exponential stability of the exact solution independent of step size under the same conditions.
关键词： Numerical simulation,Time delay,Stochastic differential equation,Hopfield neural network,Stability
更新于2025-09-23 15:23:52
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Research on the acquisition of time‐reversed electromagnetic waves based on Fourier transform theory
摘要： This paper mainly researches on the realization of time reversal mirror (TRM) based on the analog signal processing technology. Using chirped dispersive delay lines (CDDL) and based on Fourier transform theory, the solution for achieving time reversal (TR) waveform transformation has been concept proposed and theoretically analyzed. Furthermore, using two designed delay lines with the slope of ?0.4 ns/GHz, the paper experimentally achieves time-reversed waveform for a microwave signal with the time length of 1 ns. Compared to conventional implementation scheme systems with CDDLs, the newly suggested one is more stable with higher time-bandwidth products and is able to process longer time duration and wider bandwidth, which provide theoretical basis for physically achieving time-reversed systems.
关键词： dispersive delay line,time reversal mirror,Fourier transform theory,time reversal
更新于2025-09-23 15:23:52
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[IEEE 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Novosibirsk, Russia (2018.10.2-2018.10.6)] 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE) - Synthesis of Group Delay Time Correctors on the Basis of Two Types Directional Couplers
摘要： A group delay time correctors on the basis of contra-directional and trans-directional couplers are considered. The formulas for calculating the frequency characteristics of the load resistors forming a given frequency dependence of the phase and group delay time are obtained.
关键词： Synthesis,directional couplers based on coupled strip lines,group delay time correctors
更新于2025-09-23 15:23:52
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A Cyclic TDC using Variable Delay Circuit
摘要： A cyclic TDC can be implemented in a small area with high resolution but it takes long conversion time. To reduce a conversion time, we introduce variable delay circuits that can change a delay time of a pulse. We also introduce calibration techniques, an offset cancellation and delay matching, to improve linearity of the TDC. We confirmed through circuit simulation that the proposed circuit achieves a time resolution of 9.38 ps, dynamic range of 18.7 ns, sampling rate of 2 MS/s, and a power consumption of 11 mW at 1.8 V operation.
关键词： variable delay,Time-to-Digital Converter,calibration,cyclic,Multiple Delay inverter
更新于2025-09-23 15:22:29
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Geometric Distortion Correction of Spaceborne GNSS-R Delay-Doppler Map Using Reconstruction
摘要： For spaceborne Global Navigation Satellite System-Reflectometry (GNSS-R), the delay difference of direct and reflected GNSS signals among successive snapshots changes rapidly because of the high dynamics of low earth orbital and GNSS satellites. This change has to be compensated to avoid the distortion of incoherently averaged delay-Doppler map (DDM). The method to refresh the correlation window on each coherent integration time period may require too many instrument resources or too much data to be uploaded from the ground station. This letter proposes a new postprocessing approach based on the motion degradation model of DDM and the reconstruction to replace real-time compensation. Raw sampled data from UK TechDemoSat-1 are used to verify the availability of proposed approach. The results show that after reconstruction for the distorted DDM, the DDM accuracies relative to that compensated in real time are significantly improved.
关键词： Global Navigation Satellite System-Reflectometry (GNSS-R),reconstruction,Distorted delay-Doppler map (DDM)
更新于2025-09-23 15:22:29
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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) - Super-Resolution Pulse-Doppler Radar Sensing via One-Bit Sampling
摘要： This paper investigates the delay-Doppler estimation problem of a pulse-Doppler radar which samples and quantizes the noisy echo signals to one-bit measurements. By applying a multichannel one-bit sampling scheme, we formulate the delay-Doppler estimation as a structured low-rank matrix recovery problem. Then the one-bit atomic norm soft-thresholding method is proposed to recover the low-rank matrix, in which a surrogate matrix is properly designed to evaluate the proximity of the recovered data to the sampled one. With the recovered low-rank matrix, the delays and Doppler frequencies can be determined and paired. Numerical experiments are performed to demonstrate the effectiveness of our method compared with the one-bit sparse signal recovery method based on discrete dictionary.
关键词： Delay-Doppler estimation,atomic norm,compressive sensing,1-bit quantization
更新于2025-09-23 15:22:29
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A true-time-delay transmit/receive module for X-band subarray phased arrays
摘要： This letter presents the implementation of a 6-bit true-time-delay (TTD) transmit/receive (T/R) module in X-band. Improved phase linearity is achieved by using thin film coplanar waveguide transmission lines than traditional microstrip lines or lumped LC components of the most other TTD designs. In order to meet the requirement of the large dynamic temperature range in practice, the hybrid coupler reflective phase shifters with varactor diodes are adopted in long-time-delay units as temperature compensations for thermal phase drift. Experimental results of this TTD T/R module are carried out within a bandwidth of 1.2 GHz at X-band. The gain flatness is better than 1 dB and RMSE of the phase errors is less than 7° in all the transmitting and receiving delay states.
关键词： true time delay (TTD),receive module,phased array,coplanar waveguide,phase shifter
更新于2025-09-23 15:22:29