Full-wave analysis and modeling of multiconductor transmissionlines via 2-D-FDTD and signal-processing techniques

The full-wave analysis of multiconductor transmission lines on an inhomogeneous medium is performed by using the two-dimensional finite-difference time-domain (FDTD) method. The FDTD data are analyzed by using signal-processing techniques. The use of high-resolution signal-processing techniques allows one to extract the dispersive characteristics and normal-mode parameters, which include decoupled modal impedances and current and voltage eigenvector matrices. A new algorithm for extracting frequency-dependent equivalent-circuit parameters is presented in this paper. Smaller CPU time and memory are required as compared to the three-dimensional FDTD case. Numerical results are presented to demonstrate the accuracy and efficiency of this method     

Improved techniques for single-pass adaptive vector quantization

Constantinescu and Storer presented a new single-pass adaptive vector quantization algorithm that learns a codebook of variable size and shape entries; they presented experiments on a set of test images showing that with no training or prior knowledge of the data, for a given fidelity, the compression achieved typically equals or exceeds that of the JPEG standard. This paper presents improvements in speed (by employing K-D trees), simplicity of codebook entries, and visual quality with no loss in either the amount of compression or the SNR as compared to the original full-search version     

Loop-based inductance extraction and modeling for multiconductor on-chip interconnects

An efficient extraction and modeling methodology for self and mutual inductances within multiconductors for on-chip interconnects is investigated. The method is based on physical layout considerations and current distribution on multiple return paths, leading to loop inductance and resistance. It provides a lumped circuit model suitable for timing analysis in any circuit simulator, which can represent frequency-dependent characteristics. This novel modeling methodology accurately provides the mutual inductance and resistance as well as self terms within a wide frequency range without using any fitting algorithm. Measurement results for single and coupled wires within a multiconductor system, fabricated using 0.13 and 0.18 /spl mu/m CMOS technologies, confirm the validity of the proposed method. Our methodology can be applicable to high-speed global interconnects for post-layout as well as prelayout extraction and modeling.     

Capacitance extraction for electrostatic multiconductor problems byon-surface MEI

In this paper, on-surface measured equation of invariance (OSMEI) method is implemented for capacitance extraction of electrostatic multiconductor interconnect problems. OSMEI uses the same mesh as that in method of moments (MoM), but generates highly sparse matrices rather than a full matrix. In comparison with “standard” MEI which contains a few finite difference (FD) or finite element (FE) mesh layers, the number of unknowns and the computation memory can be saved. For each OSMEI equation in the multiconductor interconnects, a given node on a given conductor is forced into coupling with the few adjacent nodes on conductor itself and the few sampled nodes on other conductors. Thus, the system sparse matrices can be generated. The convergent behavior of the capacitance with the number of the nodes in the OSMEI equations has been widely investigated, Numerical examples of the capacitance extraction for two-dimensional (2-D) and three-dimensional (3-D) multiconductor interconnects show that the computing errors are within 24%. The OSMEI method may become a powerful technique for the more complex interconnect problems     

A signal-processing algorithm for the extraction of thinfreshwater-ice thickness from short pulse radar data

A radar data processing algorithm is presented which can estimate freshwater ice thicknesses both greater than and less than the normal minimum resolvable thickness. The basis for the algorithm is a model of the geophysical system and the resulting phase signature of the transfer function. The algorithm attempts to isolate this signature and estimate the relevant parameters. In principle, the method can be used to detect layering in other dielectric media. The algorithm was based on a simple model for scattering from a thin-ice layer and refined using radar returns taken over a range of thin-ice thicknesses in a laboratory environment. The method was also applied to data obtained with two different radar frequencies and over a wide range of thickness and surface roughness. The results were compared to thickness estimates from classical deconvolution methods     

Comparative analysis of parameter extraction techniques for AlGaN/GaN HEMT on silicon/sapphire substrate

We report a comparative study of artificial neural network (ANN) model and small signal model (SSM) based on extracted parameters. ANN model training is done using Levenberg-Marquardt back propagation algorithm, whereas SSM is formed by extracting circuit parameters from measured S-parameters of GaN HEMT on Silicon and Sapphire. It has been found that, for the GaN HEMT parameter extraction, it takes 85 hidden layer neurons to produce the output with higher accuracy. The optimized test and training error/performance are found to be 1.12 × 10^− 8/0.97 and 1 × 10^− 8/0.99, respectively.     

Thermal parameter extraction for bipolar circuit modelling

A practical method is presented for extracting the thermal spreading resistance of BJTs, which is needed for accurate circuit simulation. The method uses the output resistance as the temperature sensitive parameter. Measurements can be made in the time or frequency domain.<>     

DSP techniques for implementation of perfectly matched layer fortruncating FDTD domains

A new algorithm for implementing the perfectly matched layer (PML) using digital signal processing (DSP) is presented for truncating finite difference time-domain (FDTD) domains. The algorithm is based on incorporating digital filtering techniques into the PML formulation. A simple, unsplit-field and material independent PML formulation is achieved     

Accurate modeling and parameter extraction for meander-line N-well resistors

Accurate modeling and efficient parameter extraction of a scalable lumped-element model for n-well meander-line resistors that are suitable for radio frequency integrated circuit (RF IC) applications is presented. The equivalent circuit is similar to the spiral inductor model but with modifications to the element equations. Direct extraction of component values is performed by analysis of measured Y-parameters. The extracted results of the component values are physically meaningful and match those calculated using the scalable lumped-element model equations. The simulated S-parameter data from the equivalent lumped-element model shows very good agreement with the measured data up to 20 GHz.     

Simple parameter extraction method for illuminated solar cells

This paper presents a simple and successful method for evaluating the series resistance, the ideality factor, the saturation current and the shunt conductance in illuminated solar cells. The approach involves the use of an auxiliary function and a computer-fitting routine. The validity of this method has been confirmed by the way of current–voltage measurements of a commercial silicon solar cell, a module and a plastic solar cell.     

An efficient parameter extraction algorithm for MOS transistormodels

A general, direct parameter extraction algorithm that uses a small number of data points has been developed for MOS transistor models. This extraction algorithm has been tested using two transistor models in SPICE, MOS3, and BSIM. The basic idea of the algorithm is to use only one data point for each transistor parameter. Appropriate selection of the data points ensures physically reasonable values of most extracted parameters. Analytical expressions or rapidly converging numerical equations are used to calculate the parameters. Interaction between different parameters are taken into account. Good agreement between measured and simulated data is obtained from only 15 and 25 data points for MOS3 and BSIM, respectively. The total extraction time for a single transistor is around 40 s for MOS3 and 1 min for BSIM     

用正向栅控二极管的方法对场效应晶体管的参数提取

本文用正向栅控二极管的方法来提取场效应晶体管的栅氧层厚度和体掺杂浓度,尤其是在这两个变量事先都未知的情况下进行提取。首先,用器件物理推导出了以栅氧层厚度、体掺杂浓度为参数的正向栅控二极管峰值电流。然后用ISE-Dessis模拟了不同栅氧层厚度和体衬底掺杂浓度下的产生复合电流峰值的特性,用于参数提取。模拟数据的结果与正向栅控二极管的方法显示出高度的一致性。     

Forward gated-diode method for parameter extraction of MOSFETs

The forward gated-diode method is used to extract the dielectric oxide thickness and body doping concentration of MOSFETs,especially when both of the variables are unknown previously.First,the dielectric oxide thickness and the body doping concentration as a function of forward gated-diode peak recombination-generation (R-G) current are derived from the device physics.Then the peak R-G current characteristics of the MOSFETs with different dielectric oxide thicknesses and body doping concentrations are simulated with ISE-Dessis for parameter extraction.The results from the simulation data demonstrate excellent agreement with those extracted from the forward gated-diode method.     

Above-threshold parameter extraction and modeling for amorphous silicon thin-film transistors

This paper presents modeling and parameter extraction of the above-threshold characteristics of hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) in both linear and saturation regions of operation. A bias- and geometry-independent definition for field effect mobility considering the ratio of free-to-trapped carriers is introduced, which conveys the properties of the active semiconducting layer. A method for extraction of model parameters such as threshold voltage, effective mobility, band-tail slope, and contact resistance from the measurement results is presented. This not only provides insight to the device properties, which are highly fabrication-dependent, but also enables accurate and reliable TFT circuit simulation. The techniques presented here form the basis for extraction of physical parameters for other TFTs with similar gap properties, such as organic and polymer TFTs.     

Improved FDTD subgridding algorithms via digital filtering and domain overriding

In numerical simulations of Maxwell's equations for problems with disparate geometric scales, it is often advantageous to use grids of varying densities over different portions of the computational domain. In simulations involving structured finite-difference time-domain (FDTD) grids, this strategy is often referred as subgridding (SG). Although SG can lead to major computational savings, it is known to cause instabilities, spurious reflections, and other accuracy problems. In this paper, we introduce two strategies to combat these problems. First, we present an overlapped SG (OSG) approach combined with digital filters (in space). OSG can recover standard SG (SSG) schemes but it is based upon a more general, explicit separation between interpolation/decimation operations and the FDTD field update itself. This allows for a better classification of errors associated with the subgrid interface. More importantly, digital filters and phase matching techniques can be then employed to combat those errors. Second, we introduce SG with a domain overriding (SG-DO) strategy, consisting of overlapped (sub)grid regions that contain auxiliary (buffer) subdomains with perfectly matched layers (PML) to allow explicit control on the reflection and transmission properties at SG interfaces. We provide two-dimensional (2-D) numerical examples showing that residual errors from 2-D SG-DO FDTD simulations can be significantly reduced when compared to SSG schemes.     

A novel approach to parameter extraction for on-chip transformers

In this paper, a novel approach to parameter extraction for on-chip transformers based on four-port Y-parameter is presented. Compared to the previous researches, the proposed fully parameter extraction from Y-parameter has better accuracy and feasibility for both the simulation before prototype and the improvement of the design after the measurement. And the 4-port model of transformer provides the solution of the fully differential applications. The model agrees very well with measurements for a variety of transformer configuration up to its self-resonant frequency.     

基于局域网的频谱仪信号参数录取方法研究

立足实际装备,对电波监测类装备的监测原理进行了深入研究。提出了通过局域网连接频谱仪并设置参数、录取频谱仪实时显示数据参数的方法。通过设计软件实现频谱仪数据录取系统。达到丰富电波监测的测量手段、提高测量仪器的自动化水平的目的。对今后监测系统的功能实现、扩展、虚拟仪器设计都具有一定的指导作用。同时,对电波监测类装备的研制及改进也有一定的借鉴意义,可提高测量仪器的自动化水平。     

AlGaN/GaN HEMT小信号模型参数提取算法

本文采用了新型的22元件AlGaN/GaN HEMT小信号等效电路模型,较传统的模型,增加了栅漏电导Ggdf和栅源电导Ggsf来表征GaN HEMT的栅极泄漏电流。同时针对新型的栅场板、源场板结构器件,提出了一种改进的寄生电容参数提取方法,使之适用于提取非对称器件的小信号模型参数。为验证此模型,获得了S参数的测试结果和模型仿真结果,此二者的吻合度较高,表明新型的22元件小信号模型精确、稳定而且物理意义明确。     

A parameter extraction algorithm for an IGBT behavioral model

We propose a new extraction algorithm for the parameters of an insulated gate bipolar transistor dynamic behavioral model. The algorithm relies on the availability of experimental data from the manufacturers and uses Matlab optimization toolbox to extract the parameters automatically. The theoretical predictions of the algorithm are compared with both the experimental and the simulation data that use alternative extraction methods and are found to be in excellent agreement.     

2-D FDTD method for exact attenuation constant extraction of lossy transmission lines

The two-dimensional finite-difference time-domain (2-D FDTD) method is undeniably efficient for full-wave analysis of uniform transmission lines. However, conventional 2-D FDTD method ignores the spatial attenuation along the propagation direction and yields approximate results. We propose a new 2-D FDTD method for extracting exact attenuation constants of lossy transmission lines. In the proposed method, we take the variation of field components with the propagation direction into consideration and describe an iterative process for finding exact attenuation constants. Numerical experiments show that, compared with the conventional 2-D FDTD method, results given by the iterative process agree much better with analytical solutions or measured data.