A stochastic model for the interconnection topology of digitalcircuits

Rent's rule has been successfully applied to a priori estimation of wire length distributions. However, this approach is very restrictive: the circuits are assumed to be homogeneous. In this paper, recursive clustering is described as a more advanced model for the partitioning behavior of digital circuits. It is applied to predict the variance of the terminal count distribution. First, the impact of the block degree distribution is analyzed with a simple model. A more refined model incorporates the effect of stochastic self similarity. Finally, the model is further extended to describe the effects of heterogeneity. This model is a promising candidate for more accurate a priori estimation tools     

多层微波集成电路中微带线层间互连仿真

针对多层微波集成电路设计的微带线层间互连问题,介绍了垂直通孔互连、垂直带条互连和层耦合过渡互连三种高性能的互连方法,并且采用三维电磁仿真软件HFSS对这三种互连结构进行了建模和仿真.仿真结果表明,垂直通孔互连和垂直带条互连在0.1~25 GHz的频宽范围内,回波损耗S11<-20 dB,插入损耗S21>-1 dB,互连性能优良,而层耦合过渡互连在20~68 GHz内回波损耗S11<-20 dB,插入损耗S21>-1 dB,具有在毫米波频段实现互连的潜力.     

Altered phase velocity lines for low crosstalk microstrip interconnection of high-speed digital circuits: design and experimental validation

Altered phase velocity lines are a novel kind of parallel microstrip lines for high-speed interconnection of digital circuits, on which the crosstalk is reduced by the different phase velocities of propagation on the adjacent lines. In this paper, a design method is proposed to optimize the geometry sizes of the altered phase velocity lines. The measured results of a prototype altered phase velocity pair designed by the proposed method are presented to validate the design method. And the effects of the process variation are simulated to analyze the robustness of the prototype in fabrication. The altered phase velocity lines outperform the symmetric parallel microstrip lines in terms of the lower far-end crosstalk (FrdCtk) and the lower dielectric loss. This technique reduces the FrdCtk in the pair of the microstrip transmission lines and does not significantly improve the near-end crosstalk. The prototype works at the speed of 2 Gbps for low crosstalk digital signal transmission, while it can transmit the high-speed clock signal at 10.5 GHz, so the altered phase velocity lines are a useful supplementary to the existing low crosstalk interconnection concepts in the scenario that the parallel microstrips have to be placed closely on printed circuit board.     

Simple formulas for microstrip lines

A modification to earlier work is presented which allows for finite strip thickness in the calculation of microstrip impedance and line wavelength. It shows a considerable improvement in accuracy and scope over some earlier work which included strip thickness, but remains simple in form. Expressions are presented which allow calculation of Z and ?g for any microstrip geometry and relative permittivity.     

A planar-lumped model for coupled microstrip lines anddiscontinuities

A convenient model for analyzing coupled microstrip line discontinuities is presented. A planar-lumped model similar to the planar waveguide model for single microstrip lines is developed for coupled microstrip lines. Fields underneath the two strips and those fringing at the outer edge are modeled by two equivalent planar waveguides. Electric and magnetic field coupling in the gap region is modeled by a lumped network. The lumped network parameters are evaluated such that [C] and [L] matrices for the model are identical with those for coupled lines. The model is verified by comparing coupler characteristics with those obtained by the conventional coupled line analysis. Just as the planar model of a single microstrip has been used for characterizing microstrip discontinuities, the planar-lumped model developed is used for coupled line discontinuities. Examples given include coupled microstrip sections with chamfered bends located at right angles to single microstrip lines, for which the results are in good agreement with experimental values     

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.     

Crosstalk between microstrip transmission lines

Methods for prediction of crosstalk between microstrip transmission lines are reviewed and simplified for the weak-coupling case. Classical coupled transmission line theory is used for uniform lines, and potential and induced EMF methods are used for crosstalk between nonuniform lines. It is shown that the potential method is equivalent to classical coupled transmission line theory for the case of uniform lines. An experiment was performed for uniform coupled microstrip lines for frequencies from 50 MHz to 5 GHz, and good agreement between theory and measurement was obtained for both near- and far-end crosstalk     

Calculation of inhomogeneous microstrip lines

The frequency-dependent transmission properties of in-homogeneous microstrip lines are calculated by means of a waveguide model and the generalised telegraphist's equations. Examples of theoretical and experimental results are presented.     

Investigation of tapered multiple microstrip lines for VLSIcircuits

The analysis of tapered, coupled microstrip transmission lines is presented. These lines, used as interconnects between integrated circuit devices, are modeled using an iteration-perturbation approach applied in the spatial domain. From this model, a frequency-dependent scattering parameter characterization is determined. A time-domain simulation of pulse propagation through the tapered, coupled microstrip lines is performed. The frequency-domain scattering parameters are inverse Fourier transformed to obtain the time-domain Green's function. The input pulse is convolved with the Green's function, and a Newton-Raphson algorithm is applied to account for nonlinear loads. Some experimental results are shown, and a simulation approximation is proposed     

Computer-aided design for finlines and suspended-substrate microstrip lines

The computer-aided design of finlines and suspended-substrate microstrip lines are investigated. The numerical results of this paper show good agreement with those computed by other techniques for unilateral finlines and open suspended microstrip lines. The approach of this paper may be used to the computer-aided design of many other kinds of transmission lines and circuits for millimeter wave applications.     

Accurate model for open end effect of microstrip lines

A closed form expression for the equivalent line length associated with the single microstrip open end is presented for the use in microwave CAD programs. The maximum relative error involved is less than 2.5% and its effect can be shown to be below physical tolerances.     

微带线无源互调的传输矩阵理论方法

均匀微带线是微带电路的基本结构,建立微带线PIM解析模型具有重要意义。本文基于受控源等效,在微带线的集总电路等效模型中,将微带线中的分布式寄生非线性PIM源建模为二次受控电流源或电压源,从而得到微带线PIM电压和电流关系的传输矩阵表达式,建立了寄生非线性机制的微带线PIM解析计算模型;并通过对比不同长度的镀镍微带线与不同浓度掺磷工艺镀镍微带线的传输互调与反射互调规律,验证本文提出的PIM传输矩阵方法的合理性。通过该模型提取了镍镀层在0.71 GHz时的三阶相对磁导率非线性系数为1×10^-10 m²/A²。本文方法为进一步建立其他复杂结构微带电路PIM模型提供了新思路。     

Three-region analytical models for MESFETs in low-voltage digitalcircuits

Analytical models for self-aligned gate, GaAs and Si MESFET/JFETs that predict static current-voltage characteristics continuously in three regions of operation (subthreshold, linear, and saturation,) are presented. The characteristic equations are closed-form and describe behavior explicitly in terms of terminal voltages. Comparisons of model predictions with measurements in all regions of device operation are presented. In addition to physical insight into MESFET/JFET operation, the models, due to their relative simplicity, promise digital circuit simulations with accuracy, ease, and efficiency. The models indicate that in typical DCFL (direct-coupled FET logic) circuits MESFETs with undoped substrates are superior to those on highly doped substrates with respect to noise margin considerations     

一种新型微带光子带隙结构

提出一种新型微带光子带隙结构.该结构直接在微带信号线上刻蚀周期性结构,解决了该结构的封装问题,且不增加微带结构的尺寸.采用时域有限差分法分析该结构的S参数,并研究了几何参数与S参数之间的关系,得出了禁带中心频率、带宽随几何参数变化的趋势.     

Strongly convergent Green's function expansions for rectangularlyshielded microstrip lines

The exact analytical treatment of the quasi-TEM mode in various cross-sectional configurations of microstrip lines may be used on Carleman-type singular integral equations (SIEs). Their kernel is a Laplacian Green's function G with source point limited on the interface separating the dielectric media. Strongly convergent expansion for G, particularly suited for the subsequent solution of the SIE and for exact field-point evaluations in rectangularly shielded microstrip configurations, are developed. Extraction of the singular logarithmic term leads to rapidly converging series expansions for the nonsingular part. The convergence of certain of these series is further improved when the field point lies also on the interface or when the source point approaches the shielding boundaries     

Chirped delay lines in microstrip technology

In this paper, we report on a design method for chirped delay lines (CDLs) in microstrip technology. They consist in a continuously varying strip width, so that the coupling location between the quasi-TEM microstrip mode and the same but counter-propagating mode is linearly distributed in frequency. High delay×bandwidth products, over frequency ranges of several gigahertzs, can be obtained following this procedure. Experimental data confirm the design method. Real-time Fourier analysis of wideband pulses can be performed using these CDLs     

Grounding microstrip lines with via holes

Grounding microstrip circuits with via holes is an established technology and modeling isolated via holes with analytical models is well known. However, the availability of electromagnetic field solvers provides an opportunity to model via holes and the metallization surrounding them in a more realistic fashion. Calculated equivalent inductances for single and double via hole configurations are presented. A microstrip interdigital filter with grounded resonators provides experimental verification     

Shunt posts in microstrip transmission lines

Shunt posts in microstrip transmission lines are analyzed by employing the planar waveguide model. A multiple expansion method with greatly enhanced efficiency and accuracy has been achieved with the development of very fast algorithms for the computation of Schloemilch-type series. The method applies to perfectly conducting imperfectly conducting, and composite shunt posts. This approach is compared with the standard point matching technique for perfectly conducting posts. The two methods are found to be in excellent agreement in regions of overlapping applicability. A fairly wide range of computed data is utilized to develop the tools needed to incorporate the post into various microstrip circuit applications. As one application, a procedure is developed for using this post to obtain effective short-circuiting qualities over a broad frequency range. As a second application, the possibility of creating filtering devices is explored using both multiple metallic post structures and single dielectric posts     

交叉耦合微带带通滤波器

针对无线通信系统小型化的要求,设计了一种带有交叉耦合的带通滤波器,该滤波器采用带过孔的终端短路式耦合线为谐振单元,同时加入了交叉耦合线改善滤波特性;整个结构紧凑,具有插入损耗低、选择性高、带外抑制度佳等特点,实测结果与仿真吻合较好,中心频率为4.2 GHz,3 d B带宽为400 MHz,驻波比小于1.5,体积仅为8 mm×6 mm×0.7 mm。     

Propagation characteristics of superconducting microstrip lines

The modified spectral-domain approach is applied to study the propagation characteristics of high temperature superconducting microstrip lines whose signal strip and ground plane are of arbitrary thickness. In this study, numerical results for effective dielectric constant, attenuation constant, and strip current distribution are presented to discuss the effects due to frequency, temperature, strip thickness, and substrate loss tangent. In particular, the conductor and dielectric attenuation constants of superconducting microstrip line are depicted separately to discuss the mechanism of the line losses. A comparison with published theoretical and experimental results is also included to check the accuracy of the new approach's results