电容加载对频率选择表面传输特性的影响

有源频率选择表面,是指在频率选择表面中加入变容二极管或PIN二极管等有源器件构成的FSS结构,通过有源器件的可调性来实现对FSS性能的控制。文中根据有源器件的电容等效原理,设计了一种方形缝隙FSS结构,研究了电容加载对FSS传输特性的影响。仿真结果表明,加载电容后其谐振频点向低频偏移,带宽减小,且加载电容对FSS传输特性有较好的可控性。     

功率PIN二极管PSpice子电路模型

提出一种改进的PIN二极管子电路模型。该模型能够反映PIN二极管的瞬态开关特性,将基区电导调制效应考虑在内。通过PSpice软件瞬态仿真PIN二极管的正向直流、反向恢复特性。利用该子电路对新型SiC材料PIN二极管建模仿真,仿真结果表明运用新材料对二极管开关性能有显著提高。     

单光子雪崩二极管SPICE仿真模型的建立和应用

单光子雪崩二极管(SPAD)作为一种高效的光子探测器件被广泛应用于量子通信和三维成像等领域。在Cadence中建立了一个SPAD的Spice模型,通过Verilog-A语言,采用两个e指数函数的组合,以连续函数的方式描述了SPAD在盖革模式区等效电阻的动态变化。这两个e指数函数分别体现了高阻区和低阻区的等效电阻特性,解决了分段电阻模型仿真不收敛的问题。该Spice模型模拟了SPAD器件在“接收光子-雪崩产生脉冲-淬灭-复位”工作过程中的动态特性和SPAD从正偏到二次击穿的静态I-V特性。将其应用到4种不同淬灭电路的仿真中,验证了该模型的有效性和稳定性。     

4H-SiC PIN二极管的正向特性计算模型

提出了一种基于双极性扩散方程的PIN二极管的一维物理计算模型。该模型主要针对PIN二极管的正向温度特性研究,考虑了载流子扩散系数、载流子迁移率、禁带变窄效应、载流子寿命随温度变化的影响。介绍了双极性扩散方程的傅里叶级数解,利用方程的傅里叶级数解推导得到一组微分方程,并采用迭代法求解。利用该模型计算分析了4H-SiC PIN二极管在298～498 K温度下的正向电学特性,分析了PIN二极管的PN结处的电子电流和空穴电流的分布,结合SILVACO-TCAD仿真软件,设计了一种器件结构,仿真结果与计算模型基本吻合。最后结合实验数据验证了模型的准确性。     

混合PiN/Schottky二极管的研究

对混合PiN/Schottky二极管（MPS）进行研究,首先对MPS二极管的工作原理进行了分析,通过对MPS二极管、肖特基二极管、PIN二极管的伏安特性进行模拟,结果表明MPS二极管正向压降小,电流密度大,反向漏电流小,是一种具有肖特基正向特性和PN结反向特性的新型整流器。可以通过改变肖特基和PN结的面积比来调整MPS二极管的性能,与肖特基二极管和PIN二极管相比具有明显的优势,是功率系统不可或缺的功率整流管。     

基于PIN二极管加载的机载相控阵天线RCS缩减

现代飞机未来要实现射频隐身性能的最大化,就要求机载雷达的开机时间越来越短,这就为机载雷达不开机期间,相控阵天线的低RCS 隐身设计提供了可能。在天线非工作时段,加载PIN 二极管有效地减小了微带天线的RCS。PIN 二极管在正向偏置和反向偏置状态下可分别等效为电阻和电容。针对不同入射状态的平面波,依据天线感应电场分布确定PIN二极管的偏置状态,并对正向偏置状态的PIN二极管的等效电阻值进行优化,实现天线RCS的缩减。仿真计算结果表明,在天线非工作时段,优化PIN二极管的工作状态,可以实现当前情况(入射方向、频率)下天线RCS 的缩减,且RCS缩减最大可超过25 dBsm;同时又可保证天线在工作时段的辐射性能不受影响。     

微波pin二极管电阻与温度的关系

研究了四种pin二极管电阻的温度特性.结果表明二极管结面积的大小,也就是二极管结电容的大小,影响着二极管的表面复合和二极管的载流子寿命,决定了二极管的温度性能.器件的钝化方式和几何结构对二极管电阻的温度性能影响不大.结电容为0.1～1.0 pF的微波二极管,具有正的温度系数,约为线性关系,结电容越大,电阻随温度变化越大.研究结果可以用来预测pin二极管开关和衰减器的温度性能,进一步可以应用于电路温度补偿设计.     

集成PMOS管变容特性分析与仿真建模

为适应PMOS变容管在集成电路设计中的晶体管级仿真,在分析MOS变容管特性的基础上,通过确定关键点、以曲线拟合的方法建立与工艺参数相关的PMOS集成变容管高频特性模型。选用Charted 0.35μm这个特定的工艺库,并离散地改变电容连接的PMOS静态偏压、用HSpice仿真并对寄生电容提取后描绘出变容特性的准静态曲线;用Matlab对所建的简化高频变容模型进行仿真、得出高频变容曲线。仿真与理论结果相比较表明：PMOS管变容特性曲线与理论曲线的变化趋势吻合;2种仿真对变容显著区吻合较好。从而证明了PMOS集成变容管高频简化模型的正确性。     

瞬态电压抑制二极管的建模及仿真

基于0.5 μm CMOS 工艺,设计瞬态电压抑制（TVS）二极管.利用黑箱理论对该器件在高电压大电流下的反向工作特性建模,在Matlab 数值模拟工具中利用所建模型仿真,获得了包含一次击穿、二次击穿（硬失效）点的反向I –U 特性曲线;基于Silvaco TCAD 工艺器件仿真平台,经DC 仿真验证所建模型的准确性.仿真结果表明,2 种方法获得的特性曲线基本吻合,本文所建数值模型能够预测TVS 二极管瞬态电压抑制时的电特性.     

PIN二极管子电路模型与微波限幅研究

利用一种改进的PIN二极管子电路模型，通过Pspice软件瞬态仿真研究了PIN限幅器的平顶泄漏和高频限幅性能。利用该子电路对新型SiC材料PIN二极管建模仿真，仿真结果表明新型二极管可以提高限幅器的性能。     

A physics based model for the RTD quantum capacitance

A simple derivation of the form for the compact model of the quantum capacitance in a resonant tunneling diode (RTD) is presented. The quantum capacitance is shown to reduce the resistive cutoff frequency. The implementation of the model into SPICE is described. The distorting effect of the strongly nonlinear quantum capacitance on an oscillator circuit is demonstrated in a SPICE simulation. The nonlinearity becomes important for the highest frequency applications when the RTD capacitance is comparable to the capacitance in the rest of the circuit.     

Unified AC model for the resonant tunneling diode

A physics-based model is shown to yield the small-signal equivalent circuit of the resonant tunneling diode (RTD) including an analytic expression for both the quantum inductance and capacitance. This model unifies previous models by Brown et al. for quantum inductance and by Lake and Yang for quantum capacitance, and extends the RTD SPICE model of Broekaert. The equivalent circuit has been fit to both current-voltage and microwave S-parameter measurements of AlAs-InGaAs-InAs-InGaAs-AlAs RTDs from 45 MHz to 30 GHz and over biases from 0 to 0.81 V. Good agreement between the model and measurement is shown.     

太赫兹平面肖特基二极管参数模型

根据太赫兹平面肖特基二极管物理结构,在理想二极管SPICE参数模型的基础上建立了二极管小信号等效电路模型。依据该二极管等效电路模型设计了基于共面波导（CPW）去嵌方法的二极管S参数在片测试结构,并对其在0.1~50 GHz、75~110 GHz频率范围内进行了高频小信号测试,利用测试结果提取了高频下二极管电路模型中各部分电容、电阻以及电感参数。将相应的高频下电容与电阻参数分别与低频经验公式电容值和直流I-V测试提取的电阻值进行了对比,并利用仿真手段对高频参数模型进行了验证。完整的参数模型以及测试手段相较于理想二极管SPICE模型和传统的参数提取方法可以更为准确地表征器件在高频下的工作状态。该建模思路可用于太赫兹频段非线性电路的优化设计。     

并联电容对DE类功率放大器的影响

DE类功率放大器既综合了D类和E类功率放大器的优点,继承了开关型功率放大器高效率的特征,又同时避免了D类和E类功率放大器的缺陷,使其成为了人们关注和研究的热点。随着工作频率的升高,MOSFET寄生电容在DE类功率放大器并联电容的计算中无法忽略。经过理论分析得到了MOSFET寄生电容的等效电容表达式,通过使用等效电容表达式,可以获得包含MOSFET寄生电容影响的并联电容的取值,提高了DE类功率放大器设计精度,保证了DE类功率放大器在高频时的高效率。通过SPICE模型仿真和电路实验验证了分析的有效性。     

Shot-Noise in Resistive-Diode Mixers and the Attenuator Noise Model

The representation of a pumped exponential diode, operating as a mixer, by an equivalent Iossy network, is reexamined. It is shown that the model is correct provided the network has ports for all sideband frequencies at which (real) power flow can occur between the diode and its embedding. The temperature of the equivalent network is eta/2 times the physical temperature of the diode. The model is valid only if the series resistance and nonlinear capacitance of the diode are negligible. Expressions are derived for the input and output noise temperature and the noise-temperature ratio of ideal mixers. Some common beliefs concerning noise-figure and noise-temperature ratio are shown to be incorrect.     

Effect of deep impurity levels on Schottky barrier diode characteristics

In the presence of an arbitrary number of deep donor levels volt-ampere and volt-farad characteristics are obtained for the Schottky barrier diode which contains a thin dielectric layer between the metal and the semiconductor. The analysis of these characteristics shows that the deep levels can significantly influence both the capacitance and the rectifying properties of the Schottky diode; the thicker the dielectric layer, the greater the effect of the deep levels upon volt-ampere relationship and the lesser upon volt-farad one. One can determine the parameters of the deep levels from these relationships. The results of the calculation are in agreement with the data of the experiment performed.     

77K低温下MOSFET非固有电容参数提取研究

77K低温参数是制冷型碲镉汞红外焦平面探测器读出电路设计与精确仿真的关键点之一。通过研究MOSFET非固有电容的特性,并基于BSIM3通用模型对电容的描述,在77K低温下进行测试提取,得到了相关的模型参数。嵌入SPICE软件仿真对比,证明了参数的准确性。     

An advanced physics-based sub-circuit model of a punch-trough insulated gate bipolar transistor

An advanced sub-circuit model of the punch-trough insulated gate bipolar transistor (PT IGBT) based on the physics of internal device operation has been described in this article. The one-dimensional physical model of low-gain wide-base BJT is employed based on the equivalent non-linear lossy transmission line, whereas a SPICE Level 3 model is used for the diffused MOST part. The influence of voltage dependent drain-to-gate overlapping capacitance and the conductivity modulated base (drain) ohmic resistance are modelled separately. The main advantages of novel PT IGBT model are a small set of model parameters, an easy implementation in SPICE simulator and the high accuracy confirmed by comparing the simulation results with the electrical measurements of test power circuit.     

Small-signal performance of a quantum well diode

We study a small-signal performance of a quantum well (QW) diode with triangular emitter and collector barriers providing thermionic electron transport. Analytical expression for the QW diode admittance is obtained from the rigorous self-consistent small-signal analysis. Frequency dependence of the admittance is determined by a characteristic time of recharging of the QW, which is a strong function of temperature and parameters of the QW diode. Conductance as a function of temperature shows a local maximum corresponding to a resonance between a probe signal and recharging processes. Capacitance of the QW diode depends critically on the efficiency of the electron transport through the QW, and can significantly exceed all geometric capacitances associated with the device structure. Experimental data on conductance and capacitance of the QW diode as functions of temperature and frequency can be used to extract the parameters of the QW, such as QW recombination velocity, ionization energy, etc. Analytical analysis of transient currents in the QW diode allows a transparent explanation why an incremental charge-partitioning technique fails to calculate the capacitance even in the low-frequency limit     

全电容回路电容电压初始值的计算

在电路瞬态分析中经常会遇到换路后形成由全电容或同时包含理想电压源组成的全电容回路情况。由于换路瞬间电容电压不再是连续函数,即换路时uc会发生跳变,所以此时换路定则失效,这使得确定换路后电容电压的初始值变得复杂。本文依据电容元件的伏安关系导出了计算全电容回路电容电压初始值的等效电路分析法,并将这种方法推广到由任意多个电容构成的全电容回路的情况。最后通过举例说明利用该方法可使复杂的全电容回路初始值的计算变得轻而易举。