爆电换能用反铁电材料

采用爆炸冲击波作用于贮存有电极化能量的铁电体，迫使其转变成反铁电体，可释放出巨大电能量，用于一次性的高压、大功率脉冲电源。本工作研究了锆钛酸铅反铁电材料在电场、压力、温度作用下的反铁电一铁电相变性质，介绍了在爆炸冲击波作用下铁电向反铁电转变过程中电量的输出特性。     

调Q脉冲激光所产生冲击波间的非线性耦合

用调Ｑ红宝石脉冲激光辐照ＰＺＴ压电陶瓷基片表面上的银膜时，观察到所产生冲击波间的调幅现象，这表明，激光所产生的冲击波在压电陶瓷片中引起了非线性的正压电效应。     

用于宽带相控天线阵的新型低损耗延迟线

沿非线性传输线传输的微滠传播速度是直流偏压的函数，因面晨线性传输线可用作宽带延迟线。已在原理验证方案的试验中制出混合ＮＬＴＬ。测得实时延迟为１．１ｎｓ，插入损耗〈４ｄＢ，与理论非常吻合。基于２×２ＮＬＴＬ的天线阵被用来演示５ＧＨｚ时的波束控制。使用适合于我们小组在６０ＧＨｚ时测试的变容二极管的参数，预测单片ＮＬＴＬ在２０ＧＨｚ时呈现〈３．４ｄＢ的插入损耗和２００ｐｓ的延迟。     

激光脉冲和放电脉冲产生冲击波的研究

提出使用调Q激光脉冲和直流放电脉冲的复合效应在金属靶中产生冲击波.试验表明,这种新方法显著改善了先前的仅用激光脉冲产生冲击波的技术.     

激光脉冲和放电脉冲产生冲击波的研究

提出使用调Q激光脉冲和直流放电脉冲的复合效应在金属靶中产生冲击波.试验表明,这种新方法显著改善了先前的仅用激光脉冲产生冲击波的技术.     

高功率YAG激光在生理盐水中产生微等离子体的研究

利用光学阴影探测方法研究了调Ｑ－ＹＡＧ脉冲激光在生理盐水光学击穿阈值附近诱导微等离子体和冲击波产生的过程，得到了微等离子体和冲击波随人射激光能量和延迟时间而变的系列光学阴影图，并且指出了冲击波的机械作用在脉冲激光眼科医疗中的影响。     

激光冲击波加载金属材料中心压应力缺失效应

纳秒脉冲、千兆瓦级激光辐照金属材料产生高压等离子体冲击波,作用于金属材料表面并向内传播,产生残余压应力场.但在单次冲击加载时,残余压应力场中心出现的残余压应力值小于加载边缘,应用理论分析和实验测试的方法解释了这一过程,并结合激光诱导冲击波Fabbro方程和TC4钛合金动态响应模型,建立了不同形式冲击波加载TC4钛合金的数值仿真模型,分析了冲击波压力、作用时间和加载形式对中心压应力缺失的影响.     

中间电极可控的三电极放电激光器

中间电极可控的三电极放电激光器预脉冲技术［１，２］的出现使放电激光器得到了实质上的进展，这一技术开拓了在效率为３～５％下提高准分子激光器的平均功率至几千瓦的前途。在上述方法中泵浦采用两个放电电路，用以激励和维持放电。在第一个高压低能冲击波电路中，电子...     

用火花电阻计算高压毫微秒脉冲放电参量

本文用火花电阻公式研究了高压毫微秒脉冲参量（脉冲幅值、前沿、宽度）与储能电容的关系。结果表明，用火花电阻等效亚纳秒脉冲放电管击穿后的状态是合适的。     

激光冲击波诱导2024铝合金表面动态应变特性试验研究及理论分析

为研究脉冲激光冲击波诱导2024铝合金表面的动态应变特性,采用脉冲激光对2024铝合金试样表面进行冲击,并利用聚偏氟乙烯(PVDF)压电传感器测量了脉冲激光作用下2024铝合金表面的动态应变,建立了脉冲激光冲击波加载2024铝合金表面的动态应变模型,并通过试验数据对该模型进行了分析验证。研究结果表明,通过调整脉冲激光的作用参数可以控制激光冲击波与表面波不产生耦合;2024铝合金在激光冲击波诱导高应变率作用下的动态应力-应变关系曲线与在静力拉伸条件下的静态应力-应变关系曲线类似;脉冲激光冲击波加载2024铝合金表面动态应变的模型与试验结果一致。     

一种基于MMIC技术的宽带左手非线性传输线二次倍频器

本文首次报道了基于MMIC技术的左手非线性传输线宽带二次倍频器。理论上分析了左手非线性传输线的二次谐波产生原理。在GaAs半绝缘衬底上制作了4节左手非线性传输线,面积为5.4mm*0.8mm。当输入信号为20dBm时,该倍频器在26.4GHz处获得最大二次谐波输出功率为6.33dBm,对应的-6dB带宽为24GHz~43GHz。实验结果与仿真结果吻合良好。以低频放大器作为激励,该倍频器可用于低成本,有效的毫米波甚至THz信号源系统。     

Pulsed wave interconnect

Pulsed wave interconnect is proposed for global interconnect applications. Signals are represented by localized wave-packets that propagate along the interconnect lines at the local speed of light to trigger the receivers. Energy consumption is reduced through charging up only part of the interconnect lines and using the voltage doubling property of the receiver gate capacitances. In a 0.18-/spl mu/m CMOS technology case study, SPICE simulations show that pulsed wave interconnect can save up to 50% of energy and /spl sim/30% of chip area in comparison with the repeater insertion method. A proposed signal splitting structure provides reasonable isolations between different receivers. Measured S-parameters of 3.8-mm interconnect lines fabricated through CMOS foundry showed that the distortion and attenuation of a pico second signal are much less serious than the theoretical predictions. Pulsed wave interconnect also enables time division application of a single line to boost its bit rate capacity. The use of nonlinear transmission lines (NLTL) is also proposed to overcome pulse broadening and attenuation caused by dispersion and frequency-dependent losses. Pulsed waves on an NLTL may be generated, transmitted, split and detected with components realizable in bulk and SOI CMOS technologies. Tapered NLTL can be used for pulse compression. NLTL edge sharpening abilities may be applicable for signal rise time control.     

GaAs nonlinear transmission lines for picosecond pulse generation and millimeter-wave sampling

The GaAs nonlinear transmission line (NLTL) is a monolithic millimeter-wave integrated circuit consisting of a high-impedance transmission line loaded by reverse-biased Schottky contacts. The engineering of functional monolithic NLTLs is considered. Through generation of shock waves on the NLTL, the authors have generated electrical step functions with approximately 5 V magnitude and less than 1.4 ps fall time. Diode sampling bridges strobed by NLTL shock-wave generators have attained bandwidths approaching 300 GHz and have applications in instruments for millimeter-wave waveform and network measurements. The authors discuss the circuit design and diode design requirements for picosecond NLTL shock-wave generators and NLTL-driven sampling circuits.<>     

Study of the relation between doping profile and diode CVcharacteristics

An explicit formula relating Schottky-diode junction capacitance (C_j) as a function of diode bias (V_dc) and Gaussian doping profile (k) has been curve fitted to a one-dimensional numerical analysis. Two-dimensional physical simulation and the explicit formula have been applied to a Schottky diode with both simulated and analytic results compared against measurement. Incomplete ionization, edge effects, and additional charge created by traps have also been investigated using a physical simulation package, and results are presented for different trap densities. The stated formula has been implemented for a Schottky diode model using a symbolically defined device within the HP-MDS harmonic-balance simulator. This has been used as a building block for a nonlinear transmission-line (NLTL) doubler design with simulated and measured second harmonic-power output being presented. The formula, which is easily implemented in computer-aided design tools, is important for NLTL modeling and design     

一种基于SRD和NLTL的皮秒级脉冲产生电路

提出了一种利用SRD产生窄脉冲信号的方法,对其产生窄脉冲的机理进行了分析和仿真,为了使得脉冲宽度变得更窄,电路采用了NLTL结构,拓展了SRD产生窄脉冲的应用,文中分析了NLTL的工作原理。设计了基于SRD和NLTL的皮秒级脉冲产生电路,给出了测试结果,脉冲宽度为110 ps,幅度为3 V。     

Multilayer Heterostructures with Asymmetric Barriers as New Components for Nonlinear Transmission Lines to Generate High-Frequency Oscillations in the 100-300 GHz Range

A new method of generation of RF radiation in the range 100-300 GHz due to direct conversion of a video pulse into a radio pulse in nonlinear transmission line (NLTL) based on multilayer heterostructure (MLHS) with asymmetric barrier is suggested. Calculations of the capacitance-voltage characteristics and high-frequency loss in MLHS, and also of the MLHS-based NLTL dimensions are carried out with an analytical study and computer modeling of the shock wave propagation in NLTL. Some advantages of the considered method of generation in comparision with such solid state sources as Gunn devices, IMPATT diodes or different types of frequency multipliers are discussed.     

An MMIC Pulse Generator Using Dual Nonlinear Transmission Lines

We present a novel nonlinear transmission line (NLTL) pulse generator using dual-NLTL, true-time-delay, waveform-alignment technique, realized in Gallium Arsenide (GaAs) monolithic microwave integrated circuit (MMIC) technology. The diodes in these two NLTLs have opposite polarities in layout. Therefore, they are responsible for sharpening the two signals' rising and falling edges separately. A simple, low-cost, wideband combiner is adopted to combine the two fine aligned waveforms without introducing much distortion to the wideband signal. As a result, a sharp pulse is obtained with both edges compressed. With a sinusoidal signal as the input to the fabricated MMIC, a fall time of around 12 ps and rise time of 14 ps were measured at the output. This MMIC is a candidate for pulse or comb generators in many commercial and military applications     

Ultrahigh-power picosecond current switching by a silicon sharpener based on successive breakdown of structures

Ultrafast current switching by a silicon sharpener based on successive breakdown of structures has been experimentally implemented and theoretically studied. A voltage pulse with an amplitude of 180 kV and a rise time of 400 ps was applied to a semiconductor device containing 44 series-connected diode structures positioned in a 50-Ω transmission line. After device switching, pulses with an amplitude of 150 kV and a rise time of 100 ps were obtained in the transmission line. Numerical simulation showed that the electric field near the p-n junction reaches the Zener breakdown threshold (∼10⁶ V/cm) at an input voltage rise rate of more than 4 × 10¹³ V/s per structure achieved in the experiment, even when the diode structure contains technological impurities with deep ionization levels and a concentration of 10¹¹ cm⁻³.     

Nonlinear transmission lines for pulse shaping in silicon

Nonlinear transmission lines (NLTL) are used for pulse shaping. We developed the theory of pulse propagation through the NLTL. The problem of a wide pulse degenerating into multiple pulses rather than a single pulse is solved by using a gradually scaled NLTL. We exploit certain favorable properties of accumulation-mode MOS varactors to design an NLTL that can simultaneously sharpen both rising and falling edges. There is a good agreement among the theory, simulations, and measurements.     

Balanced distributed-element phase shifter

We present a balanced distributed-element phase shifter based on a nonlinear transmission line (NLTL) structure. Results show the second harmonic is more than 13dB lower at 0-V bias than a conventional single-ended NLTL phase shifter. We fabricated both balanced and conventional NLTL phase shifters with the same coplanar waveguide (CPW) design and diodes, and observed that phase shifting and insertion loss for both structures were quite similar, yet harmonic distortion was greatly improved in the balanced structure.