Analysis of power delivery network constructed by irregular-shaped power/ground plane including densely populated via-hole

The high speed and low power trend has imposed more and more importance on the design of the power distribution network (PDN) using multilayer printed circuit boards (PCBs) for modern microelectronic packages. This paper presents a fast and efficient analysis methodology in frequency domain for the design of a PDN with a power/ground plane pair, which considers the effect of irregular shape of the power/ground plane and densely populated via-holes. The presented method uses parallel-plate transmission line theory with equivalent circuit model of unit-cell grid considering three-dimensional geometric boundary conditions. Characteristics of PDNs implemented by perforated planes including a densely populated via-hole structure is quantitatively determined based on full-wave analysis using the finite-difference time-domain (FDTD) periodic structure modeling method and full-wave electromagnetic field solver. Using a circuit simulator such as popularly used SPICE and equivalent circuit models for via-hole structure and perforations, the authors have analyzed input-impedance of the power/ground plane pair. Since the presented method gives an accurate and fast solution, it is very useful for an early design of multilayer PCBs.     

高速电路电源/地层间阻抗参数计算与分析

为了快速准确地计算高速电路地层与电源层之间的阻抗参数,基于边界积分方程提出了有效的计算方法.该方法充分利用了实际电源层/地层的结构特征,将三维电磁场问题转化为二维问题,减少了计算时间.由于在计算中不需要考虑整个 电源层/地层结构的格林函数,故该方法可以用于任意边界形状的电路板.基于提出的积分方程法,分析了介质相对电介质...     

Cavity resonance suppression in power delivery systems using electromagnetic band gap structures

The utilization of electromagnetic band gap (EBG) structures is a new and promising approach in plane pair noise cavity resonance suppression. In this paper, EBG/plane pair structures are studied with full-wave methods and results are experimentally verified. A new equivalent circuit modeling approach of characterizing the frequency behavior of the entire EBG/plane pair structure is presented. The equivalent circuit of the unit cell is proposed and the procedure to extract circuit parameters is described. The influence of EBG patch parameters on the band gap characteristics is quantified and the results provide some design rules to circuit designers. Examples of applications of EBG structures to power/ground plane noise suppression are given.     

Comprehensive Electromagnetic Modeling of On-Chip Switching Noise Generation and Coupling

A comprehensive modeling methodology is presented for the investigation of on-chip noise generation and coupling due to power switching. The backbone of the methodology is an electromagnetic model for the on-chip portion of the power grid. This allows for the impact of the displacement current density and, hence, electromagnetic retardation, to be taken into account in the accurate modeling of the power grid behavior at picosecond switching speeds. In this manner, and through the interfacing of this model with an electromagnetic model for the package portion of the power grid, which is described in terms of a multiport rational matrix transfer function, the impact of package-chip electrical interactions on switching noise can be modeled with electromagnetic accuracy. The electromagnetic model for the power grid is complemented by a resistance-capacitance model for the semiconductor substrate, which is capable of modeling local substrate induced noise coupling between neighboring circuits. Finally, distributed resistance, inductance, capacitance and conductance circuits for signal wires are extracted and used to provide for a transmission line-based modeling of crosstalk and power grid induced signal degradation. Transient simulations using the proposed comprehensive model are carried out using a hybrid time-domain integration scheme which combines a SPICE-like engine for the analysis of all circuit netlists and the nonlinear drivers incorporated in the model with a numerical integration algorithm suitable for the expedient update of the state variables in the discrete electromagnetic model for the power grid.      

Comprehensive Broad-Band Electromagnetic Modeling of On-Chip Interconnects With a Surface Discretization-Based Generalized PEEC Model

A surface integral equation formalism is proposed for broad-band electromagnetic modeling of on-chip signal and power distribution networks. The discrete model is developed in the spirit of the partial element equivalent circuit (PEEC) model, which is extended with several attributes that lead to enhanced modeling versatility, modeling accuracy, and numerical solution robustness from dc to multigigahertz frequencies. Instead of the volumetric discretization model, which has dominated the PEEC-based schemes for handling the tall and slim cross sections of the on-chip wiring, the proposed model relies on a computationally more efficient conductor surface discretization. Key to the effectiveness and accuracy of the proposed surface discretization is the definition of a frequency- and position-dependent impedance quantity on the conductor surface. Its numerical computation over the frequency bandwidth of interest is expedited through the implementation of a complex frequency-hopping algorithm. The resulting effective surface impedance is combined with a mixed triangular/rectangular meshing of the conducting surfaces for the approximation of the surface electric current and charge densities. A systematic strategy for the identification of loops in the resulting discrete model is used to ensure a numerically stable mesh analysis-based PEEC formulation for on-chip signal and power distribution modeling with electromagnetic accuracy from dc to multigigahertz frequencies.     

A Finite-Element Domain-Decomposition Methodology for Electromagnetic Modeling of Multilayer High-Speed Interconnects

The complicated geometry of high-density interconnect structures in multilayer, planar substrates is one of the major hurdles in the application of finite element methods for their multigigahertz electromagnetic analysis. In addition to compounding the complexity in the generation of the finite element grid, the multilayer nature of the structures and their multiscale attributes result in finite element systems of very large dimension which, more often than not, are not well conditioned. This paper presents a domain decomposition methodology for overcoming these hurdles. More specifically, the proposed methodology utilizes the multiple power and ground planes used in such structures as natural physical boundaries for their decomposition into a set of subdomains, each one of which is meshed and discretized separately from the rest. The electromagnetic interaction between the domains is effected through the enforcement of tangential field continuity conditions at the voids and via holes present at the power and ground planes. In particular, a Krylov subspace model order reduction approach is used to facilitate the broadband solution of the multilayer interconnect structure. The proposed modeling methodology is demonstrated through its application to the electromagnetic analysis of several multilayer interconnect structures.     

高速双面共面结构印刷电路板电特性仿真

为了适应高速双面共面印刷电路板的不规则布线结构,本文采用三维电磁参数提取的部分元等效电路方法对任意形状接地/馈电板进行自动分割及单元建模,然后对包括I/O缓冲器在内的非线性电路进行时域信号响应分析.高速双面共面结构印刷电路板电特性的仿真与实际测试结果吻合较好,表明了方法的有效性.     

Spectral theory of a semi-infinite transmission line over a groundplane

The electromagnetic modeling of wave propagation along a semi-infinite wire with ground return is addressed. External excitation, via plane wave is considered. Both wire and ground plane are assumed to be perfect conductors. Through a spectral approach, a one-port Thevenin model of the structure, valid for any distance between wire and ground, is developed. Such a model allows to evaluate rigorously the limits and the accuracy of the transmission line (TL) equations     

A novel power plane with super-wideband elimination of ground bounce noise on high speed circuits

A novel L-bridged electromagnetic bandgap (EBG) power/ground planes is proposed with super-wideband suppression of the ground bounce noise (GBN) from 600Mz to 4.6GHz. The L-shaped bridge design on the EBG power plane not only broadens the stopband bandwidth, but also can increase the mutual coupling between the adjacent EBG cells by significantly decreasing the gap between the cells. It is found the small gap design can prevent from the severe degradation of the signal quality for the high-speed signal referring to the perforated EBG power plane. The excellent GBN suppression performance with keeping reasonably good signal integrity for the proposed structure is validated both experimentally and numerically. Good agreement is seen.     

EBG combined isolation slots with a bridge on the ground for noise suppression

In this paper, a coplanar electromagnetic bandgap (EBG) structure is presented to realise with L-bridge unit cell on the power plane that is combined isolation slots with straight/meander-bridge on the ground plane. The proposed structure with meander-bridge on the ground plane possesses an ultra-wide band gap from 0.22 GHz to 20 GHz with isolation below ?30 dB, which is remarkable better than traditional EBG. The lumped equivalent-circuit model for the structure is presented and analysed to explain the mechanism of the improvement of noise suppression. The cut-off frequency for the proposed structure is obtained by theoretical analysis. It is shown that the increase of equivalent inductance of the bridge influences the cut-off frequency. The meander-bridge on the ground plane is adopted to broaden the stopband and significantly enhance the suppression depth. The validity of the presented structure is verified by the simulation compared to the measurement.     

Susceptibility analysis of wiring in a complex system combining a3-D solver and a transmission-line network simulation

This paper deals with the application of electromagnetic field-to-transmission-line coupling models for large cable systems analysis. It emphasizes the use of Agrawal's (1980) model applied here in a numerical simulation of an electromagnetic susceptibility problem up to 500 MHz. Based on the concepts of EM topology, the proposed methodology consists in calculating the incident fields with a three-dimensional (3-D) computer code and the coupling on cables with a multiconductor transmission-line network computer code. In order to validate the efficiency of this methodology in an industrial context, an experiment has been performed on a prototype wiring installed in a Renault Laguna car, stressed by an EM plane wave. Numerous validation configurations have been carried out. First, the prototype cable network under study has been tested on a ground plane to validate the coupling model but also, to validate the cable-network topology itself. Second, EM fields have been measured onto the structure and inside the structure. Then, they have been compared to 3-D calculations, performed with an FDTD code. Third, comparisons between measurements and calculations of bulk currents and voltages on 50 Ω loads on the wiring have been achieved     

A S-Bridged Inductive Electromagnetic Bandgap Power Plane for Suppression of Ground Bounce Noise

In this letter, a novel power plane using an inductive S-bridged electromagnetic bandgap (EBG) is proposed for ultra wideband suppression of the ground bounce noise. The S-shaped bridge detouring unit cells effectively increase the power plane inductance. -30 dB stopband is realized from 220 MHz to 7 GHz. The stopband lower limit (220 MHz) of the proposed EBG has been greatly reduced from that (550 MHz) of L-bridged EBG. It is expected that the number of local decoupling capacitors for the power plane integrity is reduced using the proposed S-bridged EBG without the self resonance effect.     

Modeling of striplines between a power and a ground plane

In this paper, a stripline model is presented for coupled signal lines routed between a power and a ground plane based on multiconductor transmission line (MTL) theory. Through a suitable diagonalization of the MTL equations for striplines, the transverse electromagnetic (TEM) parallel-plate mode is decoupled from the stripline mode. In this way, stripline models that are obtained assuming ideal planes at ground potential can be extended to take into account the nonideal behavior of the planes. The presented model is applied to represent mode conversion due to vias, holes in the reference planes, and terminations of the stripline. Influence of inhomogeneous media is discussed.     

Neural Network Inverse Modeling and Applications to Microwave Filter Design

In this paper, systematic neural network modeling techniques are presented for microwave modeling and design using the concept of inverse modeling where the inputs to the inverse model are electrical parameters and outputs are geometrical parameters. Training the neural network inverse model directly may become difficult due to the nonuniqueness of the input-output relationship in the inverse model. We propose a new method to solve such a problem by detecting multivalued solutions in training data. The data containing multivalued solutions are divided into groups according to derivative information using a neural network forward model such that individual groups do not have the problem of multivalued solutions. Multiple inverse models are built based on divided data groups, and are then combined to form a complete model. A comprehensive modeling methodology is proposed, which includes direct inverse modeling, segmentation, derivative division, and model combining techniques. The methodology is applied to waveguide filter modeling and more accurate results are achieved compared to the direct neural network inverse modeling method. Full electromagnetic simulation and measurement results of Ku-band circular waveguide dual-mode pseudoelliptic bandpass filters are presented to demonstrate the efficiency of the proposed neural network inverse modeling methodology.     

Coupling of vias in electronic packaging and printed circuit board structures with finite ground plane

A full wave method is presented for modeling and analyzing multiple interactions among vertical vias in densely packaged integrated circuits and printed circuit board with ground plane of finite extent. In such structures, the TEM mode in the planar structure is excited and can propagate and cause interaction of waves among vias. Reflections will also occur at the edges of the finite ground plane. The electromagnetic analysis methodology is an extension of the previous methodology in analyzing multiple scattering among vias for infinite ground plane . The analysis is based upon the cylindrical wave mode expansion of the magnetic field Green's function, the Foldy-Lax multiple scattering formalism and utilizing the resonator modes of a circular cavity. The circular resonator modes are transformed into cylindrical waves onto the cylindrical via structures. Numerical results illustrate the physics of the underlying resonance scattering problems. We consider the cases of a) two coupled active vias of differential mode and b) two coupled vias of common mode. Results are also illustrated for ground plane resonance and the effects of shorting vias on such resonance. The effects of off-centering and the presence of idle vias are also illustrated.     

A 3-D hp finite/infinite element method to calculate power deposition in the human head

The electromagnetic power deposition and transfer properties of a G1 continuous head model reconstructed from magnetic resonance imaging (MRI) data are investigated by using the coupled hp finite/infinite element (FE/IE) method. The discretization error is controlled by a self-adaptive process driven by an explicit a posteriori error estimate. Based on the benchmark problem of reproducing the Mie series solution, the scattering of a plane wave on the curvilinear head model is used to evaluate the hp FE/IE approach and calibrate the error bound. The radiation pattern from a short dipole antenna modeling a cell phone, is analyzed in terms of the level and distribution of the specific absorption rates (SAR). The numerical experiments show that the hybrid hp FE/IE implementation is a competitive tool for accurate assessment of human electromagnetic exposure.     

Ground loss effects in power line reradiation at standard broadcastfrequencies

Reradiation of a standard broadcast antenna's signal from a high-voltage power line is often analyzed by computer modeling. The resonant behavior of a power line operating over lossy ground is investigated using the numerical electromagnetics code (NEC) which uses the Sommerfeld-Norton (SN) ground model, for a highly accurate computation of the interaction of a power line with lossy ground. It is shown that lossy ground damps the resonant response of the power line and so, substantially reduces the reradiated field. Since the SN ground option is costly in CPU time, the effects of lossy ground were approximated using the tower footing impedance concept. A systematic evaluation of the accuracy of the approximation is made. An approximate technique for incorporating the approximate techniques presented are sufficiently accurate that the economical method-of-images solution can be used in most cases     

High dielectric constant thin film EBG power/ground network for broad-band suppression of SSN and radiated emissions

We experimentally demonstrated the great advantages of a high dielectric constant thin film electromagnetic bandgap (EBG) power distribution network (PDN) for the suppression of power/ground noises and radiated emissions in high-performance multilayer digital printed circuit boards (PCBs). Five-layer test PCBs were fabricated and their scattering parameters measured. The power plane noise and radiated emissions were measured, investigated and related to the PDN impedance. This successfully demonstrated that the bandgap of the EBG was extended more than three times, covering a range of hundreds of MHz using a 1-cm /spl times/ 1-cm EBG cell, the SSN was reduced from 170 mV to 10 mV and the radiated emission was suppressed by 22 dB because of the high dielectric constant thin film EBG power/ground network.     

机场数据在合成视景系统中的应用研究

针对合成视景系统显示机场和跑道的需求,提出了一种利用标准机场数据库,在开放绘图架构下的机场合成显示方法.首先分析了AMDB数据的来源、格式与建模方法;然后使用跨平台开源的图形处理库OSG对机场、跑道和周围地形进行了三维视景合成.重点研究了AMDB数据绘图映射和建模方法、机场三雏模型与地形的合成显示技术.建立了KSFO机...     

改进的二维三维混合时域不连续伽辽金方法

对高速信号通过电源板时的电源完整性(power integrity, PI)问题进行研究时, 因为电源板中主要模式分布为零阶平行板模式, 可以采用二维简化以提高效率.而对于隔离盘或其它存在纵向不连续性的区域, 则应采用三维算法以保证精度.将两者结合起来的一种二维三维(2D/3D)混合时域不连续伽辽金(discontinuous Galerkin time domain, DGTD)方法可以兼顾精度与效率, 有效地处理这类电磁全波计算问题.其中二维、三维方法采用同一套三棱柱离散的网格, 通过适当设置基函数, 二维区域与二维区域之间可以方便快速地相互转化.随着电磁波的传播, 二维、三维的适用区域是随时间、空间动态变化的.为了准确地捕捉这种动态变化, 文中提出的一种改进的自适应判据, 在每个时间歩对电磁场进行检测, 从而动态地判定二维简化区域.与现有技术的判据控制绝对误差不同, 该方法对相对误差进行控制, 效率高、精度好, 对于不同的结构适应性强.通过数值实验, 与商业软件和全三维(3D)DGTD方法的结果进行了比较和验证.