Crosstalk noise modeling of multiwall carbon nanotube (MWCNT) interconnects using finite-difference time-domain (FDTD) technique

This paper presents an accurate and efficient model for the transient analysis of multiwall carbon nanotubes (MWCNT) using finite-difference time-domain (FDTD) method. The proposed model can be essentially used to analyze the functional and dynamic crosstalk effects of coupled-two MWCNT interconnect lines. Using the proposed model the voltage and current can be accurately estimated at any point on the interconnect line and furthermore, the model can be extended to coupled-n interconnect lines with a low computational cost. Crosstalk induced propagation delay, peak voltage, and its timing instance are measured using the proposed model and validated by comparing it to the HSPICE simulations. Over a random number of test cases it is observed that the average error in estimating the noise peak voltage on a victim line is less than 1%. The proposed model is extremely useful for accurate estimation of crosstalk induced performance parameters of MWCNT interconnects.     

FDTD based transition time dependent crosstalk analysis for coupled RLC interconnects

The performance of high density chips operating in the GHz range is mostly affected by on-chip interconnects. The interconnect delay depends on many factors, a few of them are inputs toggling patterns, line ＆ coupling parasitics, input rise/fall time and source/load characteristics. The transition time of the input is of prime importance in high speed circuits. This paper addresses the FDTD based analysis of transition time effects on functional and dynamic crosstalk. The analysis is carried out for equal and unequal transition times of coupled inputs. The analysis of the effects of unequal rise time is equally important because practically, it is quite common to have mismatching in the rise time of the signals transmitting through different length wires. To demonstrate the effects, two distributed RLC lines coupled inductively and capacitively are taken into consideration. The FDTD technique is used because it gives accurate results and carries time domain analysis of coupled lines. The number of lumps in SPICE simulations is considered the same as those of spatial segments. To validate the FDTD computed results, SPICE simulations are run and results are compared. A good agreement of the computed results has been observed with respect to SPICE simulated results. An average error of less than 3.2% is observed in the computation of the performance parameters using the proposed method.     

Crosstalk analysis for a CMOS gate driven inductively and capacitively coupled interconnects

This paper deals with crosstalk analysis of a CMOS driven capacitively and inductively coupled interconnect. The Alpha Power Law model of MOS transistor is used to represent a CMOS driver. This is combined with a transmission line-based coupled RLC model of interconnect to develop a composite model for analytical purpose. On this basis a transient analysis of crosstalk noise is carried out. Comparison of the analytical results with SPICE extracted results shows that the error involved is nominal.     

The transient analysis of latch-up in CMOS transmission gate induced by laser

An analytical model of transient latch-up in CMOS transmission gate induced by laser is established. The time-dependent current characteristics of the parasitic silicon controlled rectifier (SCR) under different injected photocurrent are illustrated. The model analyzes the trigger conditions for latch-up and describes the dynamic process varying with time. The photocurrent threshold causing latch-up under different pulse widths and repetition frequencies is obtained, which agrees well with the experimental results reported in the literature.     

CMOS design and analysis of low-voltage signaling methodology for energy efficient on-chip interconnects

This paper provides a comparative study of the low-voltage signaling methodologies in terms of delay, energy dissipation, and energy delay product (energy×delay), and sensitivity technology process variations, and noise. We also present the design of two symmetric low-swing driver-receiver pairs for driving signals on the global interconnect lines. The key advantage of the proposed signaling schemes is that they require only one power supply and threshold voltage, hence significantly reducing the design complexity. The proposed signaling schemes were implemented on 1.0 V CMOS technology, for signal transmission along a wire-length of 10 mm. When compared with other counterpart symmetric and asymmetric low-swing signaling schemes, the proposed schemes perform better in terms of delay, energy dissipation and energy×delay.     

Thermal effect analysis of silicon microring optical switch for on-chip interconnect

The silicon microring resonator plays an important role in large-scale, high-integrability modern switching matrixes and optical networks, as silicon photonics enables ring resonators of an unprecedented compact size. But as the nature of resonators is their sensitivity to temperature, their performances are vulnerable to being affected by thermal effect. In this paper, we analyze the dominant thermal effects to the application of silicon microring optical switch. On the one hand we theoretically analyze and experimentally measure the thermal crosstalk among adjacent microring optical switches with different distances, and give possible solutions to minimize the affect of thermal crosstalk. On the other hand we analyze and measure the thermooptic dynamic response of microring switch; the experiment shows for the thermal-tuning that the rising edge is around 2μs, and the falling edge is around 35μs. We give the explanation of the asymmetric rise-time and fall-time.     

分析非均匀填充圆柱介质谐振器的二阶精度FDTD公式

从积分形式的Maxwell方程出发，利用连续函数的Taylor级数展开，严格地给出了包含介质交界面的二阶精度时域有限差分(FDTD)公式，解决了以往FDTD法处理非均匀介质填充区域问题时只有一阶精度的问题。分析表明，为了获得二阶精度，除了需要引入适当等效介电常数外，还必须采用适当非均匀网格。该方法被用于轴对称圆柱介质谐振器的分析。计算结果与理论值吻合良好，计算精度比传统的FDTD方法提高了一个数量级以上。     

加载天线目标RCS的FDTD计算与分析

提出一种带角点的细导线模型和传统FDTD相结合的方法分析加载斜拉式线天线目标散射特性.为进一步减小目标离散时的台阶化误差和节省计算资源(内存和时间),给出一种简化的共形FDTD(SCFDTD)算法.通过坐标旋转使天线长段平行于某固定坐标轴,然后建立带有角点的细导线FDTD模型.以变形网格面积与正常网格面积之比1/6作为SCFDTD算法的判据,既简化了已有CFDTD算法的复杂度,又不失其物理意义.与传统FDTD方法和实验测量结果对比数值计算例子表明了该方法的可行性与有效性.     

FDTD分析准八木天线的算法实现

介绍时域有限差分（FDTD）法计算准八木天线驻波比的算法实现方法。文中利用模型描述文件对天线进行了建模和网格划分;将各向异性完全匹配层（UPML）吸收边界分区编写,并利用区域的对称性简化了程序;采用带内阻的电压源作为激励源;最后从总电压中分离出入射电压和反射电压,得到了准八木天线的驻波比。实际制作了一个准八木天线并进行了测试,计算结果与实测结果基本一致,表明该实现方法是正确和有效的。     

一种多导体传输线瞬态响应时间步积分法

针对时域有限差分法分析非均匀有损耗多导体传输线瞬态响应的差分振荡问题,提出一种多导体传输线瞬态响应的时间步积分方法。该方法对不等长非均匀有损多导体传输线建模时,无需对耦合传输线进行解耦,能够较方便地求解耦合状态下的不等长非均匀有损多导体传输线系统。所提方法首先对电波方程中的空间微分算子进行差分离散,然后采用梯形积分法对时间微分算子进行积分,最终得到分析不等长非均匀有损多导体传输线瞬态响应的时间步积分算法。该算法不仅应用于不等长非均匀有损多导体传输线模型进行数值计算和理论分析,并对传输线终端端接线性负载和非线性负载的两种情况进行仿真验证。仿真结果表明该方法是有效的。     

管道内微带天线的FDTD全波分析与设计

针对金属管道中探测作业无缆机器人微波供能系统,对其能量接收部分的接收天线进行了设计, 采用时域有限差分法(FDTD)结合PML边界条件全波分析了管道内圆极化微带天线,数值结果与测试结果比较吻合,验证了此数值算法的有效性.     

Design and analysis of planar printed microwave and PBG filters using an FDTD method

In this paper, various planar printed microwave and photonic band-gap (PBG) filters have been designed and analyzed by applying the finite difference time domain method, together with an unsplit-anisotropic perfectly matched layer technique as treatments of boundary conditions. The implemented solver was first validated by comparing the computed data with those published in literature, and a good agreement was observed between the results. Then, based on the specified design criteria, various microwave and PBG filters were designed and analyzed, in which the theoretical predictions matched well with the computed results for the characteristics of the proposed filters.     

The analytical model for crosstalk noise of current-mode signaling in coupled RLC interconnects of VLSI circuits

With the continuous advancement of semiconductor technology,the interconnects crosstalk has had a great influence on the performances of VLSI circuits.To date,most of the research about the interconnects of VLSI circuits focus on the voltage-mode signaling (VMS) scheme while the current-mode signaling (CMS) scheme is rarely analyzed.First of all,an equivalent circuit model of two-line coupled interconnects is presented in this paper, which is applicable to both the CMS and VMS schemes.The coupling capacitive and mutual inductive are taken into account in the equivalent circuit model.Secondly,the output noise of CMS and VMS schemes are investigated in the paper according to the decoupling technique andABCD parameter matrix approach at local level,intermediate level and global level,respectively.Moreover,the experimental results show that the CMS interconnects have lesser noise peak,noise width and noise amplitude than the VMS interconnects in the same cases,and the CMS scheme is especially suitable for the global interconnects communication of VLSI circuits.It is found that the results obtained by ABCD parameter matrix approach are in good accordance with the simulation results of the advanced design system.     

基于FDTD的微带漏波天线分析的新方法

使用时域有限差分法对微带漏波天线进行数值仿真,得到了微带漏波天线TE01模下的电场分布,对微带漏波天线的电波传播特性进行初步的讨论.提出新的经验计算公式微带漏波天线漏波传播系数,所得漏波传播系数曲线与实测数据以及比较数据十分吻合.     

等离子体散射分析的改进型交替隐式时域方法

提出了一种改进的交替隐式时域有限差分(FDTD)方法,运用该方法分析了等离子体涂覆导体圆柱的散射特性,为等离子体隐身技术的运用提供了一定的理论指导.该方法在整个问题空间采用完整场形式的场量进行迭代计算,并运用中心差分格式离散极化电流密度辅助方程.仿真实验表明,提出的算法具有无条件稳定特性,其计算效率明显优于以往文献提出的交替隐式FDTD方法,在精度和效率上也稍高于普通的显式FDTD方法.     

基于GPU的并行FDTD方法在二维粗糙面散射中的应用

利用显卡(Graphics Processing Unit, GPU)加速时域有限差分(Finite-Difference Time Domain, FDTD)法计算二维粗糙面的双站散射系数, 介绍了FDTD的理论公式以及计算模型.采用各向异性完全匹配层(Uniaxial Perfectly Matched Layer, UPML)截断FDTD计算区域.重点讨论了基于GPU的并行FDTD计算粗糙面双站散射系数的并行设计方案计算流程.在NVIDIA GeForce GTX 570显卡上获得了50.7×的加速比.结果表明:通过对FDTD计算粗糙面散射问题的加速, 极大地提高了计算效率.     

An analysis method for high-speed circuit systems

A new method for analyzing high-speed circuit systems is presented. The method adds transmission line end currents to the circuit variables of the classical modified nodal approach. Then the matrix equation describing high-speed circuit system can be formulated directly and analyzed conveniently for its normative form. A time-domain analysis method for transmission lines is also introduced. The two methods are combined together to efficiently analyze high-speed circuit systems having general transmission lines. Numerical experiment is presented and the results are compared with that calculated by Hspice.     

一种基于遗传算法的VDSM IC电源网格动态IR-drop分析新方法

提出了一种用于超深亚微米集成电路电源网格IR-drop验证的新方法.该方法以遗传算法为基础,与已有的分析方法相比,该方法兼具静态IR-drop分析法和动态IR-drop分析法的优点,适用于包含大型组合模块的超大规模集成电路,可主动寻找电路中最大IR-drop.通过对ISCAS85电路实现的验证,发现了静态分析法不能发现的芯片边缘IR-drop问题.实验结果验证了该方法的正确性与有效性.     

Performance analysis for the dynamic virtual path bandwidth control method in ATM networks

Broadband ISDN (integrated services digital network) should provide various kinds of communication services for multimedia traffic, including voice, computer data, still picture and motion video, and an ATM (asynchronous transfer mode) technology is expected to satisfy those demands. In ATM networks, a VP (virtual path) concept is introduced for simplifying the network resource management. However, if the bandwidth of each VP is fixed, it cannot absorb traffic load fluctuation. In this case, it is likely to happen that one VP has no remaining bandwidth while other VPs on the same physical link have free capacities. Another extremity is that a VP is not introduced, and that all VCs along the same physical link share the whole bandwidth of the link. This can achieve an efficient use of the link, but it apparently requires complicated call set-up procedures. In this paper, we propose a new dynamic VP bandwidth control method, in which the bandwidth allocated to each VP is dynamically changed according to traffic fluctuation. More specifically, in the case that multiple VPs are multiplexed on the same link between two nodes, when the utilization of some VP is increased, that VP requests an additional bandwidth. When the traffic load becomes low and the utilization of a VP is decreased, a part of the assigned bandwidth is released. We consider two methods for this purpose; one is the basic method in which the bandwidth increase request is issued after the VP bandwidth is exhausted. The other is the look-ahead method where the bandwidth increase is requested in advance before the bandwidth starvation. An approximate analysis for the above methods is provided, and the validation of its accuracy is assessed by comparing with simulation results. Through numerical examples, we show that our methods can provide performance improvement in terms of call loss probabilities of each VP.