Sensitivity analysis of a multiconductor transmission line

In this paper, the theory for the sensitivity analysis of a multiconductor line is described, and the sensitivities of the receivingend voltage and power with respect to the various line parameters have been evaluated.     

Electromagnetic propagation along a multiconductor transmission line in a tunnel--approximate analysis

A general approximate formalism is presented which enables one to calculate in a simple manner the electromagnetic propagation characteristics of a multiconductor transmission line in an underground tunnel. This approach circumvents the tedious task of locating the complex roots of the exact mode equation. The formalism is based on an approximate treatment of the single-wire case due to Wait.Lambda, Omega, andZ_{s}in Wait's single wire formula for the propagation constant are replaced with corresponding quadratic forms in the eigenmodal wire currents to generalize the formula to an arbitrary number of wires. The foundations of this approximate approach in standard perturbation theory are indicated, lending physical meaning to the approximations. A simple example involving a two-wire line is presented to establish the order of accuracy to be expected in using this formalism.     

不等长多导体传输线模型串扰问题分析

不等长多导体模型为电力电子系统中传输线的一种常见结构,其串扰问题关系到整个系统的正常运行。采用时域有限差分格式对传输线方程进行差分离散,并结合基尔霍夫定律,对不同多导体系统连接位置进行处理,推导出多导体传输线上电压电流迭代公式,实现了整个模型上全部电压电流的同步求解,并通过算例验证了该方法在分析电大尺寸传输线电磁干扰问题时的有效性。     

The inductance matrix of a multiconductor transmission line inmultiple magnetic media

A simple relationship between the inductance matrix and the auxiliary capacitance matrix is given. For a multiconductor transmission line consisting of N_c conducting cylinders in inhomogeneous media consisting of N_d homogeneous regions with permeabilities μ_i and permittivities ϵ _i, the inductance matrix [L] for the line is obtained by solving the magnetostatic problem of N_c conductors in N_d regions with permeabilities μ _i. The capacitance matrix [C] for the line is obtained by solving the electrostatic problem of N_c conductors in N_d regions with permittivities ϵ _i. It is shown that [L]=μ₀ϵ₀[C^'] ^-1, where [C^'] is the capacitance matrix of an auxiliary electrostatic problem of N_c conductors in N_d regions with relative permittivities set equal to the reciprocals of the relative permeabilities of the magnetostatic problem, i.e. ϵ^' _i/ϵ₀=μ₀/μ_i     

基于传输线方程的多根非平行传输线串扰分析

非平行结构的传输线在电力电子系统中普遍存在,当其上通有电压和电流信号时,会在周围传输线上产生串扰响应。采用时域传输线方程建立多根非平行传输线之间的串扰模型,结合FDTD方法,分析在脉冲集总源激励下受扰导线始端和终端负载上的串扰电压响应特性,将其结果与仿真结果对比,验证了该方法的正确性。研究结果表明,非平行结构中受扰线始端和终端负载上的串扰电压响应随着传输线离地面高度的增大而增大,随着传输线之间夹角的增大而变小,且减小的趋势逐渐减弱,从而为线缆间的串扰防护提供了参考依据。     

端接非线性负载的不等长传输线瞬态分析

对时域有限差分(FDTD)法应用于不等长多导体传输线端接非线性负载的情况进行了介绍.首先给出了多导体传输线电报方程和差分公式;然后介绍了不等长传输线的仿真模型;在此基础上,最后通过建立端接非线性负载的不等长多导体传输线模型,对该情况下传输线两端的电压响应进行了分析.数值仿真结果说明了FDTD法解决此类问题的正确性和有效性,为不等长传输线瞬态分析的进一步研究打下了基础.     

Direct computation of multiconductor transmission line capacitance and charge distribution

The per-unit-length capacitance parameter of multiconductor transmission line (MTL) is commonly extracted with indirect matrix transform method, which is complex and time-consuming. To solve the problem, an improved method to directly compute the MTL capacitance is proposed, which can be applied in the transmission line structure with arbitrary shaped cross-section and arbitrary separate distance. This method imports voltage conversions and matrix operations to simplify the complexity, improves computational efficiency by about 600% with results as accurate as previous method. The novel method presents a clear charge distribution map of MTL, whereas precious method will experience a tortuous process to get charge distribution.     

Time-domain upper bounds for signals on a multiconductor transmission line behind an aperture

A technique for bounding the maximum voltages at terminations of a multiconductor transmission line (MTL) located behind an aperture-perforated conducting screen excited by an electromagnetic field in the time domain is developed. The electromagnetic field is coupled through a small aperture as the excitation of a multiconduetor transmission line behind the aperture. A model is presented in terms of traveling waves and multiple refleetion phenomenon. These traveling waves transfer energy to the terminations. The energy at a terminatian is translated into voltages from which the upper bounds are determined. The upper bounds are obtained using vector norms and associated matrix norms.     

Frequency-domain upper bounds for signals on a multiconductor transmission line behind an aperture

This paper develops a technique for bounding the maximum voltages and currents at terminations of a muiticonductor transmission line (MTL) located behind an aperture-perforated conducting screen excited by an electromagnetic field in the frequency domain. The electromagnetic field is coupled through a small aperture as the excitation of a multiconductor transmission line behind the aperture. A model is presented in terms of external and internal sources which in turn create traveling waves on the multiconductor transmission line. These traveling waves transfer energy to the terminations. The energy at a termination is translated into voltages and currents from which the upper bounds are determined. These upper bounds are obtained using vector norms and associated matrix norms. The formulation is presented in the frequency domain to obtain useful upper bounds for analysis of multiconductor transmission line geometries with aperture excitation.     

Calculation of transients on unsymmetrical multiconductor line systems using the graphical method

The `graphical method? previously discussed for transient calculation in single-conductor transmission-line systems is generalised for unsymmetrical multiconductor lines having N conductors. The solution equations are expressed in a form suitable for digital programming.     

Response of circular symmetric multiconductor microstrip line to an electromagnetic field

The primary-secondary field idea is used to determine the response of a circular symmetric multiconductor microstrip line (CSMSL) to an external electromagnetic plane wave. The primary field is obtained analytically for the cases of oblique TM/sup z/ and TE/sup z/ polarized incidence. The secondary field is determined using excited multiconductor transmission line theory. The method is examined to obtain the effect of external illumination on a four-strip CSMSL and some useful results are obtained.     

不等长非均匀有损耗传输线FDTD瞬态分析

以分析等长均匀无损耗多导体传输线的时域有限差分（FDTD）法为基础,在考虑传输线损耗的情况下,对不等长非均匀多导体传输线进行分析。首先,在考虑传输线损耗的情况下给出传输线上各点电压和电流的迭代计算公式;其次,利用该公式对不等长非均匀有损耗传输线模型进行数值计算和理论分析;最后,通过仿真实验,其结果表明所提计算方法是正确和有效的。该方法对不等长非均匀有损耗传输线的研究提供理论计算参考。     

A memory-based high-speed digital delay line with a largeadjustable length

The digital delay line concept is based on a dynamic three-transistor cell memory, with pointer access and offers high operating frequency, large maximum length, and low power dissipation. The adjustable delay requires only a small overhead for control logic. An experimental chip with 60 K transistors, which utilizes this concept, has been built in a 1.5-μm CMOS technology. The adjustable delay ranges from 1 to 4096 clock cycles for a 4-bit-wide data word. Correct operation of the chip has been verified for clock frequencies in the range of 3 kHz to 30 MHz. Therefore the circuit is suitable for audio as well as video applications     

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     

Carbon-dioxide laser with high power per unit length

A CO2-N2-He laser is described in which the discharge plasma was excited in the volume between two coaxial silica tubes by means of a radial r.f. field. Additional power was fed into the plasma by a longitudinal d.c. field applied to internal electrodes. With an outer tube 46.5 mm in diameter and 1.2m long, an output power of 250W was obtained at 12% efficiency.     

Number of zeros of a complex polynomial inside the unit circle

A very simple method is given for constructing a matrix whose principal minors are equal to the minors in the Schur-Cohn theorem for determining the number of zeros of a complex polynomial inside the unit circle.     

Optimum length of one-stage polarization-mode dispersion compensators with a fixed delay line

We investigate the performance of the one-stage polarization-mode dispersion (PMD) compensator with a fixed delay line. We find that there exists an optimum delay line length for the PMD compensator and the optimum delay line length decreases with the increase of signal bandwidths. We show that such PMD compensators, when optimized, can achieve almost the same performance as that achieved by those with a variable delay line.     

Deterministic modeling of the (shielded) outdoor power line channel based on the multiconductor transmission line equations

In this paper, a complete methodology is proposed for the deterministic modeling of the channel transfer functions associated with underground power line access networks, in the light of the Multiconductor Transmission Line Theory. Some multiconductor power line cables are analyzed in detail, and their fundamental propagation characteristics (definition of eigenmodes, phase velocity, characteristic impedance, lineic attenuation) are related to the geometry of the conductors and the material properties. A multidimensional scattering matrix formalism is then introduced to perform an accurate analysis of the global power line network including multiconductor cable segments, derivation points, and termination loads. An illustrative example of a power line access network with three types of cables (with different numbers of conductors), 20 derivations, and five remote terminals, is finally proposed.     

Evolutionary generation of 3-D line-segment circuits with a broadside-coupled multiconductor transmission-line model

Evolutionary generation of three-dimensional microwave line-segment circuits embedded in a multilayer structure is presented. Connections of the line segments and their lengths are expressed by sets of parameters, which are evolutionarily optimized by the genetic algorithms. Practical optimization time is achieved by introducing models of broadside-coupled multiconductor transmission lines instead of full-wave electromagnetic (EM) calculations. The scattering parameters of the models are connected with the scattering parameters of vias, and are synthesized into that of the whole circuit. Using line segments, we can obtain not only small components for limited-space applications, but also large components for wide-band frequency specifications without increasing computational complexity. Two bandpass filters and a bandstop filter were designed and tested by an EM simulator. The bandpass filters were also fabricated and measured. The results validated our proposing procedure.