Three-dimensional vectorial eigenmode algorithm for nonparaxialpropagation in reflecting optical waveguide structures

A novel full vectorial eigenmode propagation algorithm based on the method of lines is presented, which is applied to the three-dimensional analysis of reflecting longitudinal varying optical waveguides with high refractive index contrast between the transverse and propagation direction. Results for the computation of the vectorial field in a polarisation converter are shown and discussed in comparison with previously published data     

Embedded microstrip interconnection lines for gigahertz digitalcircuits

Transmission line structures are needed for the high-performance interconnection lines of GHz integrated circuits (ICs) and multichip modules (MCMs), to minimize undesired electromagnetic wave phenomena and, therefore, to maximize the transmission bandwidth of the interconnection lines. In addition, correct and simple models of the interconnection lines are required for the efficient design and analysis of the circuits containing the interconnection lines. In this paper, we present electrical comparisons of three transmission line structures: conventional metal-insulator-semiconductor (MIS) and the embedded microstrip structures-embedded microstrip (EM) and inverted embedded microstrip (IEM). In addition, we propose closed-form expressions for the embedded microstrip structures EM and IEM and validate the expressions by comparing with empirical results based on S-parameter measurements and subsequent microwave network analysis. Test devices were fabricated using a 1-poly and 3-metal 0.6 μm Si process. The test devices contained the conventional MIS and the two embedded microstrip structures of different sizes. The embedded microstrip structures were shown to carry GHz digital signals with less loss and less dispersion than the conventional MIS line structures. S-parameter measurements of the test devices showed that the embedded microstrip structures could support the quasi-TEM mode propagation at frequencies above 2 GHz. On the other hand, the conventional MIS structure showed slow-wave mode propagation up to 20 GHz. More than 3-dB/mm difference of signal attenuation was observed between the embedded microstrip structures and the conventional MIS structure at 20 GHz. Finally, analytical RLCG transmission line models were developed and shown to agree well with the empirical models deduced from S-parameter measurements     

Hybrid-mode analysis of homogeneously and inhomogeneously dopedlow-loss slow-wave coplanar transmission lines

A hybrid-mode analysis is presented to characterize the propagation properties of uniplanar slow-wave MIS (metal-insulator-semiconductor) coplanar transmission lines. The effect of homogeneous versus gradually inhomogeneous doping profile is investigated as well as the influence of the metal conductor losses and finite metallization thickness on the slow-wave factor and the overall losses. Numerical results indicate that thick-film MIS CPWs can support a slow-wave mode with moderate loss up to 40 GHz when the line dimensions are kept in the micrometer range. Furthermore, it is found that an inhomogeneous doping profile can reduce the overall losses and that the effect of metal conductor losses in heavily doped MIS structures is only marginal. On the other hand, in weakly doped or insulating GaAs material a lossy metal conductor leads to a higher propagation constant, exhibiting a negative slope with increasing frequency     

New prospective coplanar metal-insulator-semiconductor (MIS)monolithic structure

Research work on various MIS transmission lines is well documented. Useful slow-wave propagation with low loss is always exhibited in recently proposed lower frequency ranges (several GHz). The author is concerned with the essential properties of the micrometre-size coplanar MIS lines. A new loss-reducing monolithic MIS is proposed with reference to physical considerations to ensure a low-cost mechanism     

高温超导引线的传输特性

从电磁学理论入手,给出了引线的基本理论。对高温超导引线的传输特性进行了分析,并对金属引线和导引线的性能进行了比较。得到以下结论：（１）在超导能隙频率下,金属引线的衰减系数比高温超导引线大几个数量级;（２）金属引线的相速与信号频率无关,易出现信号发散,而超导引线在低于能隙率的情况下,相速与频率无关,信号不发散;（３）金属引线对脉冲信号的延迟时间比超导引线高。     

Realisation of switched capacitor delay lines and Hilbert transformers

Realisation of switched capacitor delay lines, both for one-way and two-way signal sample propagation are presented. Finite impulse response (FIR) filters can be constructed using tapped delay lines; particularly, the discussed two-way delay lines are useful for the realisation of filters with antisymmetric impulse responses, such as Hilbert transformers. The switches can be controlled using two-phase clocks.<>     

Finite Element Analysis of Lossy Waveguides-Application to Microstrip Lines on Semiconductor Substrate

The development of Maxwell's equations is made considering the electromagnetic fields as vector distributions. With the aid of the finite element method, an analysis of lossy shielded inhomogenous waveguides of arbitrary shape is described. To solve the complex matrix system an iterative procedure is presented. The method is applied to study the propagation on MIS or Schottky contact microstrip lines.     

Rigorous analysis of planar MIS transmission lines

The realisation of distributed microwave integrated circuits can be expected by using very low phase velocity propagation modes on MIS and Schottky planar transmission lines. Up to now, the frequency behaviour of such lines has been obtained by using analytical models. We present a rigorous analysis of a MIS microstrip line, the validity of which is testified by comparison to experimental values.     

直线法的误差分析及精度改进

１９８０年Ｕ．Ｓｃｈｕｌｚ和Ｒ．Ｐｒｅｇｌａ等首次将直线法用于分析电磁场边值问题［１］．近年来这种技术先后被用于分析微带类、Ｆｉｎｌｉｍｅ类微波平面导波结构和复杂截面波导的传输问题［２～４］，微波平面结构的谐振和不连续性问题［５～７］，极化栅和频率选择表面的电磁散射问题［８～９］以及进气道ＲＣＳ的计算［１０］等．但是关于这种方法的误差分析、线数选取原则和精度改进等还未看到较系统的论述．本文对直线法的误差进行了分类论述，讨论出了直线法的线数选取原则．最后阐述了提高直线法精度的几种途径。     

An accurate model for dynamic crosstalk analysis of CMOS gate driven on-chip interconnects using FDTD method

An accurate and time efficient model of CMOS gate driven coupled-multiple interconnects is presented in this paper for crosstalk induced propagation delay and peak voltage measurements. The proposed model is developed using the finite difference time domain (FDTD) technique for coupled RLC interconnects, whereas the alpha power law model is used to represent the transistors in a CMOS driver. As verified by the HSPICE simulation results, the transient response of the proposed model demonstrates high accuracy. Over the random number of test cases, crosstalk induced peak voltage and propagation delay show average errors of 1.1% and 4.3%, respectively, with respect to HSPICE results.     

Invited paper Characteristics of travelling waves along the non-linear transmission lines for monolithic integrated circuits: a review

A general analysis of non-linear wave propagation along transmission lines with voltage-dependent capacitance is presented. In particular, slow-wave structures like MIS and Schottky-barrier strip lines are examined. A spatial periodicity is included explicitly. The theoretical treatment is based on suitable equivalent circuits leading to characteristic wave equations. With regard to practical devices, the solutions show a variety of different phenomena as determined by the parameters of the non-linearity, dispersion and dissipation and the boundary conditions. Experimental results performed on a slow-wave model line are included.     

Methods of theoretical analysis and computer modeling of theshaping of electrical pulses by nonlinear transmission lines andlumped-element delay lines

The mechanism by which high-power electrical pulses can be sharpened by propagation along nonlinear transmission lines and lumped-element delay lines is described with emphasis on the production of pulses with very fast leading or trailing edges. A survey of some of the mathematical techniques that have been applied to the propagation of electrical signals along nonlinear lines and ladder networks is presented, and the limitations of these techniques are discussed. The processes that both produce and limit pulse sharpening on nonlinear lumped-element delay lines are examined, and it is found that the wave equation, which describes the propagation of electrical signals along such networks, predicts that an electrical pulse will decompose into an array of solitons. An approximate formula for estimating the degree of pulse sharpening that can be produced on a delay line with a given number of sections is derived, and its accuracy is compared with experimental results. Numerical integration techniques for solving the nonlinear differential and difference equations that result from the mathematical analysis of nonlinear lines and networks are discussed, and the propagation of a voltage pulse along a lumped-element delay line containing nonlinear capacitors is simulated using a computer model based on an efficient algorithm     

Time-domain response of MIS coplanar waveguides for MMICs

An MIS coplanar waveguide propagating a slow-wave mode has been characterised in the time domain. The theoretical analysis proposed to obtain the time-domain response of the line gives results in good agreement with measurements. The circuit analysis used is suitable for the determination of spurious propagation effects, inherent to the use of miniature waveguides encountered in MMICs, such as Schottky contact coplanar lines and coupled microstrip lines laid on MIS substrates.     

Low-loss microwave interconnections by using polymeric based coplanar waveguides on low resistivity silicon substrates

In this paper a new approach to manufacture low losses coplanar waveguide (CPW) lines for microwave and millimeter wave signal processing is presented. A photolithographic process is performed by using SU-8 thick negative photo-resist on low resistivity silicon wafers, to obtain CPW lines elevated with respect to the substrate, in order to take advantages, in terms of propagation losses, from transmission line structures which are almost on-the-air.     

A Digitally Controlled Shunt Capacitor CMOS Delay Line

Delay-controlled CMOS delay lines have been proved useful in a number of applications, notably the digitization of short time intervals. This paper introduces a new kind of CMOS delay line, in which the delay element is an array of capacitors controlled by a digital signal vector. This choice allows for a robust implementation of the circuitry controlling the delay generation, while the maximum speed attainable by the line is high compared to the maximum speed achieved by other delay line architectures. The delay line presented here was designed to produce an accurately tunable 16 × 0.5ns delay under large temperature, supply voltage, and technological process quality variations.     

CHARACTERISTICS OF MICROSTRIP TRANSMISSION LINES

An efficient hybrid field solution to microstrip transmission lines is presented byusing SLE and SLM modes in spectral domain.It by-passes the lengthy process of formulatingthe determinant equation for the unknown propagation constant.Compared with spectral domainadmittance approach,this method is clear in both physical and mathematical senses and may beapplied to a variety of structures.     

Optimal interconnection circuits for VLSI

The propagation delay of interconnection lines is a major factor in determining the performance Of VLSI circuits because the RC time delay of these lines increases rapidly as chip size is increased and cross-sectional interconnection dimensions are reduced. In this paper, a model for interconnection time delay is developed that includes the effects of scaling transistor, interconnection, and chip dimensions. The delays of aluminum, WSi2, and polysilicon lines are compared, and propagation delays in future VLSI circuits are projected. Properly scaled multilevel conductors, repeaters, cascaded drivers, and cascaded driver/ repeater combinations are investigated as potential methods for reducing propagation delay. The model yields optimal cross-sectional interconnection dimensions and driver/repeater configurations that can lower propagation delays by more than an order of magnitude in MOSFET circuits.     

Effects of inductance on the propagation delay and repeaterinsertion in VLSI circuits

A closed-form expression for the propagation delay of a CMOS gate driving a distributed RLC line is introduced that is within 5% of dynamic circuit simulations for a wide range of RLC loads. It is shown that the error in the propagation delay if inductance is neglected and the interconnect is treated as a distributed RC line can be over 35% for current on-chip interconnect. It is also shown that the traditional quadratic dependence of the propagation delay on the length of the interconnect for RC lines approaches a linear dependence as inductance effects increase. On-chip inductance is therefore expected to have a profound effect on traditional high-performance integrated circuit (IC) design methodologies. The closed-form delay model is applied to the problem of repeater insertion in RLC interconnect. Closed-form solutions are presented for inserting repeaters into RLC lines that are highly accurate with respect to numerical solutions. RC models can create errors of up to 30% in the total propagation delay of a repeater system as compared to the optimal delay if inductance is considered. The error between the RC and RLC models increases as the gate parasitic impedances decrease with technology scaling. Thus, the importance of inductance in high-performance very large scale integration (VLSI) design methodologies will increase as technologies scale     

基于递归算法的含频变参数架空线的模量计算模型

利用常实数模变换矩阵,对含频变参数的架空线系统在模域进行了研究.为了便于时域卷积,对不同模量上的特征阻抗和延时函数在复频域采用矢量匹配法进行拟合.提出了含频变参数架空线的模量计算模型,既保证了较高的计算精度,又简化了计算.最后,应用所提出的算法对架空线的瞬态波过程进行仿真计算,验证了算法的正确性和有效性.该算法可推广至水平分层土壤情况,同时结合时域有限差分法(FDTD)可得到架空线上各点的电压和电流波过程.