FDTD在宽带MIC魔T设计中的应用

首先简要介绍平面魔T的发展历史,指出了MIC和MMIC中魔T设计和分析存在的困难,具体分析了一种由槽线与微带线构成的魔T的物理原理,并给出了详细的等效电路图和计算公式.针对现在微波电路中魔T设计存在的困难,本文提出了将等效电路方法和时域有限差分算法相结合的设计分析方法,随后以这种魔T类型为例,设计了一个用在微波集成电路中的魔T,中心频率为6GHz、带宽为3-9GHz,详述了该方法的整个过程.在应用时域有限差分(FDTD)分析时,为了计算的准确性,采用了PML边界条件和非统一尺寸网格划分(non-uniform grid)方法.     

A unified approach for the steady-state analysis of resonantconverters

A generalized approach for the steady-state analysis of resonant converters is presented. Different resonant converter tank circuit configurations are combined into a single tank circuit referred to as a generalized tank circuit. The load presented to this tank circuit is represented by an AC equivalent resistance, and simple complex circuit analysis is used to analyze such a generalized tank circuit. This type of unified approach simplifies the method of analysis for different configurations and eliminates the need for analysis of different schemes separately. In addition, in a computer program, the results for a particular scheme can be obtained by opening or shorting the nonrequired tank circuit components of the generalized scheme. The effect of high-frequency transformers and other parasitics can be taken into account in the analysis. A design example is presented to illustrate the method of designing a converter, and experimental results are presented to verify the analysis     

Power combiner for LINC amplifier

A power combiner for nonlinear amplifiers based on the Wilkinson circuit method using lumped elements is presented. Compared to existing designs, the third harmonics of the two different signals, fed into the two input ports of the circuit, are matched and decoupled as well. The circuit is described and theoretical and measured results are presented.     

A CAD-suitable approach for the analysis of nonuniform MMIC andMHMIC transmission lines

A new method of moment-based formulation for the solution of the telegraphist's equations in nonuniform transmission lines is presented. Entire domain basis functions that build in a frequency variation are used to cover wider frequency and physical dimension ranges. The results obtained using the proposed formulation are validated by comparison to those obtained by a CAD package and to measured data. Different nonuniform lines in microstrip and coplanar technologies on monolithic microwave/millimeter wave integrated circuit (MMIC) and miniaturized hybrid microwave integrated circuit (MHMIC) substrates are investigated with an application to the design a matched taper transition in a MMIC coplanar line     

Tunable Y-type waveguide power divider as standard mismatch

A method is proposed for generating standards of voltage standing wave ratio (v.s.w.r.) of values ? 2 by a waveguide device consisting of a Y-type junction matched to the input guide (power divider), with a tunable ratio of power division, an adjustable sliding short circuit and a matched load. A detailed analysis of errors is given, which considers the effects of a possible deviation of the symmetry of the junction and of the uncertainties in the determination of the reflection coefficient and of the position of the short circuit.     

Current-mode divide-by-two circuit

A current-mode divide-by-two circuit is presented which does not rely on well matched components and a high gain opamp. The circuit can be employee as a reference-generating circuit of an algorithmic current-mode A/D convertor.<>     

一种基于神经元MOS的直扩匹配滤波器新结构

鉴于神经元MOS晶体管的多输入信号控制以及可变阈值等特点,本文提出一种基于神经元MOS的直接序列扩频(DS)通信系统中匹配滤波器的新结构,并对其进行了MATLAB结构验证和HSPICE电路仿真。与我们前期提出的基于神经元MOS的匹配滤波器相比,新结构的匹配滤波器提高了抗干扰能力,简化了电路结构。     

Optimum noise-source reflection-coefficient design with feedbackamplifiers

The issue of designing a low-noise microwave feedback amplifier for a given optimum noise-source coefficient Γ_Sopt is addressed and a set of original formulas is presented. These expressions define a new procedure which does not rely on computer optimization in order to get the required noise performance of the low-noise amplifier stage. The technique permits the design of a circuit which is simultaneously noise and power matched at its input port without an input matching circuit. This method can be used to screen devices for an optimum noise performance and it provides the essential mathematical tool for designing the core of a feedback amplifier     

A revised formulation of modal absorbing and matched modal sourceboundary conditions for the efficient FDTD analysis of waveguidestructures

A revised formulation of modal absorbing and matched modal source boundary condition is proposed for the efficient analysis of a waveguide circuit with the finite-difference time-domain (FDTD) method. The formulation is based on a suitable translation operator modeling, in time domain, the propagation in a uniform hollow waveguide. By applying this operator, a multimodal absorbing boundary condition is obtained. Moreover, a source algorithm is developed that generates a given incident wave, while absorbing each modal component reflected from a discontinuity. The source is capable of separating incident and reflected waves without requiring any presimulation of long uniform waveguides. The validity and effectiveness of the formulation is verified by means of three numerical experiments. The first two refer to waveguide discontinuities. In these cases, the FDTD results are compared to mode-matching results. The third example is a transition from waveguide to printed circuit transmission line. The numerical simulation is compared with published experimental results. The presented examples show that the generalized scattering matrix of a waveguide circuit can be evaluated accurately in the smallest computational space allowed by the structure     

Exact reliability analysis of combinational logic circuits

A novel method is presented for the exact reliability analysis of combinational logic circuits. A model is developed that allows the logic circuit to be presented by a circuit equivalent graph (CEG). The reliability is analyzed by a systematic searching of certain subgraphs from the CEG. A computer algorithm and an example are given. The method gives the exact solution to the combinational logic circuit reliability-analysis problem. This is achieved by proper gate/circuit modeling, which allows the enumeration of all redundant fault vectors in a given circuit. Due to the concept of dominance among fault vectors, the number of necessary enumerations is appreciably reduced, and thus circuits with a few tens of gates can be efficiently analyzed     

Finite element method using port truncation by perfectly matchedlayer boundary conditions for optical waveguide discontinuity problems

A powerful algorithm based on a finite element method (FEM) is newly formulated for the analysis of waveguide discontinuities. In an earlier approach, FEM was applied to the finite region with discontinuities, and a mode expansion technique was applied to the uniform waveguides that are connected to the input and output ports of finite region. Although, in the present approach, the uniform waveguides are replaced by perfectly matched layer (PML) boundary conditions, it is possible to treat periodically varying waveguide structures such as photonic crystal (PC) waveguides. A combined method of beam propagation method (BPM) and FEM is also shown in such a form that a mode expansion technique is not required. To show the validity and usefulness of the present approach, numerical examples for optical gratings, circuit components based on PC waveguides and optical directional couplers are presented     

An efficient crosstalk parameter extraction method for high-speedinterconnection lines

A proposal is presented for an effective extraction method for crosstalk model parameters of high-speed interconnection lines. In the extraction procedure, mutual capacitance and mutual inductance of the coupled interconnection lines are extracted based on S-parameter measurement, time-domain-reflectometry (TDR) measurement and subsequent microwave network analysis. The extraction method is useful for characterizing homogeneous guiding structures, where the propagation of coupled transverse electromagnetic (TEM) modes is supported. In contrast to previous extraction methods, the suggested procedure requires fewer on-wafer probing steps and does not need matched terminations in the test device for high-frequency probing. The extracted models can be readily used with simulation program with integrated circuit emphasis (SPICE) circuit simulation. The procedure can also be used for modeling the crosstalk in packaging structures and multichip modules (MCMs). The proposed procedure has been successfully applied to the crosstalk model extraction of on-chip interconnection lines. Crosstalk model parameters were obtained for different line structures, spaces, and widths. Finally, the validity and reliability of the extracted models were examined by comparing a SPICE circuit simulation using the extracted crosstalk model parameters with high-speed time-domain crosstalk measurement. A close agreement was observed in the amplitude and pulse shape between the simulation and the measurement, showing the accuracy and usefulness of the proposed extraction method     

A time-domain full-wave extraction method of frequency-dependentequivalent circuit parameters of multiconductor interconnection lines

A time-domain full-wave method for the extraction of frequency-dependent equivalent circuit parameters of multiconductor interconnection lines is presented in this paper. The circuit parameters extracted by this method can be inserted into circuit simulation software to investigate time-domain responses of a high-speed IC system with multiconductor interconnects. Because the definitions of the voltage and the current are not unique in full-wave analysis, transformation among circuit parameters according to different definitions of the voltage and current is also presented. The method is based on the finite-difference time-domain (FDTD) method, and the reliability of this method is illustrated by its application to representative problems     

空军总医院全军临床航空医学中心简介

通过建立声表面波(SAW)匹配滤波器的等效能量结构,利用交叉场电路等效模型,在频域上对SAW匹配滤波器进行分析.对于中心频率为60 MHz、抽头数32位的SAW匹配滤波器,采用上述方法得到的插入损耗和-3 dB带宽的计算值和测试值分别相差小于1 dB和1 kHz,证明了其正确性和有效性.     

The probability of error detection in sequential circuits using random test vectors

In this article a method is presented for evaluating the probability of detecting (PD) a single stuck-fault in a sequential circuit as a function of the number of random input test vectors. A discrete parameter Markov-model is used in the analysis to obtain closed-form expressions for PD. The circuit is partitioned into three parts, the input and output combinational logic and the memory. The analysis is based upon the stationary-state transition matrix associated with a circuit, and the probability that a fault in one of the partitions produces an error at the output of that partition when a random input vector is applied. Results are presented to show how this problem can be reduced to that of testing an equivalent combinational circuit.     

Comparison of the Acquisition Performance of the Matched Filter and Integrate-and-Dump Receivers in a Multipath Delay and Fading Environment

The Matched Filter and the Integrate-and-Dump circuit techniques are both attractive acquisition methods for CDMA systems. Acquisition using the matched filter technique has attracted considerable interest in recent years since it shows a better performance in the presence of Gaussian noise. On the other hand acquisition using an integrate-and-dump circuit is attractive because it is less complex to implement. However, the acquisition performance can be affected significantly by the channel characteristics. In this paper, a numerical method and a computer simulation have been developed in order to compare the two acquisition systems in different propagation environments. Results show that the acquisition using a matched filter is much faster than that using the integrate-and-dump circuit for the reception of spread-spectrum signals in the presence of Gaussian noise. However, in a multipath delay and fading environment, the results show that the mean acquisition time using the matched filter is not always faster than that using the integrate-and-dump circuit. The results show that it depends on the fading, the delay, the number of users and the signal-to-noise ratio.     

容差分析在舵机反馈采样控制电路中的应用

基于空空导弹对精确控制的要求,以及电路容差分析2种方法的基本原理,结合某空空导弹舵机反馈采样控制电路,提出了基于Saber软件进行电路容差分析方案。采用Saber软件研究电路参数偏差的容差仿真分析方法 ,具体分析了电位器±10%的精度是制约舵反馈电路容差能力的重要因素,并提出提高电路可靠性设计措施。     

Tri-Band Wilkinson Power Divider Using a Three-Section Transmission-Line Transformer

The analysis and design of a triple-band equal-split Wilkinson power divider are described. The circuit proposed is well matched and isolated at three arbitrary frequencies. The design procedure for the three-section transmission-line transformer based equal-split Wilkinson power divider derived from the ideal transmission-line model is provided. Simulated and experimental results in microstrip technology are presented to verify the idea and the derived equations.     

数据采集器模拟电路自检测技术的研究

将数据采集器的模拟部分按功能分为PGA、共模抑制电路和滤波电路3个部分研究,在分析了各元件参数对对电路性能影响的基础上,提出了一种能将故障定位到元件的检测方案,通过软件验证证实了其有效性,对今后的研究具有一定的指导意义。     

用于WCDMA系统的一种新型神经元MOS复数匹配滤波器

提出了一种新型神经元MOS复数匹配滤波器结构,用于实现WCDMA系统中复四相扩频调制信号的解扩运算.主要对关键电路进行了分析,与线性运算器件实现的复数匹配滤波器电路相比,具有结构简单的优点,大大降低了器件数目,HSPICE仿真结果验证了该电路结构的可行性.