Efficient EMI reduction in multilayer PCB using novel wideband electromagnetic bandgap structures

Electromagnetic interference is a significant problem in high‐speed circuits. To minimize its effect and improve the electrical characteristics of circuits such as signal integrity and electromagnetic compatibility, the application of an electromagnetic isolation structure with electromagnetic bandgap (EBG) is considered. In this paper, a novel wideband EBG structure is proposed for EMI reduction in multilayer printed circuit boards (PCB), in which a kind of improved L‐bridge is used as additional series inductance, and the equivalent inductance can be increased significantly. Compared to the traditional mushroom‐liked EBG structure with the same parameters, the L‐bridge structure can broaden the relative bandwidth to nearly 250%, with a significant decline of the center frequency. The effectiveness and accuracy of this structure are verified by both simulations and measurements. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Study of planar structure applying reciprocity technique combined with MGEC and analysis of discontinuity

The 3D structure electromagnetic computation presents several difficulties related to the volume mesh. In fact, the entire volume space must be taken into account even the smallest details. In this article, we propose a formulation based on the reciprocity theorem combined with the generalized equivalent circuit method to model a planar 3D structure with both coaxial and planar excitation. The major advantage of this formulation is the fact to reduce the computational volume into 2D ones in the discontinuity plane. In addition, we focused on the calculation of the discontinuity between the excitation source and the planar structure to determine the exact behavior of the electric coaxial excitation model. The obtained current density, electric field distributions, and the input impedance are presented and discussed in the following sections. An approximately good agreement of input impedance with those obtained by the simulator and measurement is shown.     

A new technique for the extraction of equivalent‐circuit parameters from 3D monoblock filters

A new technique is presented for the extraction of accurate equivalent circuits from 3D structures using a commercial finite‐element software package. The technique is based on first electromagnetic principles; it exploits the post‐processing capabilities of the software and is suitable for analysing structures of arbitrary geometry and materials. Application of this technique reduces a three‐pole monoblock ceramic GSM filter to its equivalent circuit. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

Accurate Simulation of RF MEMS VCO performance including phase noise

A new coupled circuit and electrostatic/mechanical simulator (COSMO) is presented for the design of low phase noise radio frequency (RF) microelectromechanical systems (MEMS) voltage-controlled oscillators (VCOs). The numerical solution of device level equations is used to accurately compute the capacitance of a MEMS capacitor. This coupled with a circuit simulator facilitates the simulation of circuits incorporating MEMS capacitors. In addition, the noise from the MEMS capacitor is combined with a nonlinear circuit-level noise analysis to determine the phase noise of RF MEMS VCO. Simulations of two different MEMS VCO architectures show good agreement with experimentally observed behavior.     

The compiled logic simulator

A two-value, zero-delay simulator that computes signatures and analyzes fault coverage for circuits with built-in self-test (BIST) is described. The simulator, called the compiled logic simulator (CLS), is used with a monitor that simulates BIST control logic at a high level. The simulator's compiled code is well suited to the IBM 3090 pipeline and fault simulation using flat random patterns. The linear-feedback-shift-register simulation monitor is discussed. Performance results are presented. Fault simulation with one million random patterns on a 40000-gate circuit was done in 16 CPU minutes     

Simulating logic circuits: A multiprocessor application

Circuits, especially logic circuits, are highly concurrent structures: signals flow along many parallel paths at once. This native concurrency, a function of both circuit size and topology, can be exploited in simulating these circuits on parallel machines. Simulation efficiency is affected by machine, language, and simulator implementation parameters like cycle speed, parallelism overhead, and partitioning of the circuit within the simulator, as well as by the amount of native concurrency. The experimental logic simulatorconsim, written in Multilisp and implemented on a 34 element shared-memory multiprocessor, was used to investigate these issues.     

Design and optimization of RF ICs with embedded linear macromodels of multiport MEMS devices

In this paper, we demonstrate efficient modeling approach for simulation, analysis, design, and optimization of multiport radio frequency microelectromechanical systems (RF MEMS) resonating structures embedded in RF circuits. An in‐house finite element method (FEM) solver is utilized to develop accurate and efficient macromodels that capture all the essential characteristics of the device. Using the datasets generated from the FEM simulations, the artificial neural network models are trained for two‐way mapping between the physical input and electrical output parameters. Realized model is implemented in a circuit simulator, enabling a simple yet accurate circuit simulator compatible modeling and optimization procedure instead of memory and time demanding FEM analysis. The derivation of dynamic macromodels with preserved electromechanical behavior of the multiport resonating structures is also presented. Capabilities of the proposed approach are demonstrated with several examples featuring capacitively actuated MEMS resonating structures: a clamped–clamped beam, a free–free beam, and a coupled clamped–clamped beam. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Modeling of mutual coupling of arbitrary order in coupled circuits and array antennas

This article presents a fundamental strategy for accurately modeling the mutual coupling of arbitrary order in any large‐scale electromagnetic structures and high‐density integrated chips such as antenna array elements and coupled circuit elements. The proposed method starts from the modeling of the first‐order mutual coupling, and it consists of two main steps. First of all, an equivalent circuit model describing low‐order mutual coupling (adjacent coupling) is characterized and established, of which each parametric value is accurately extracted by making use of a numerical calibration technique. Then, the circuit model for high‐order mutual coupling (crossover or crosstalk coupling) is generated from the lower order models, and it can further be used for the modeling of mutual coupling of any higher order. The accuracy and efficiency of the proposed method are demonstrated by three different kinds of structure including a linear phased array antenna, a finite periodic electromagnetic structure, and a planar low‐pass filter. This novel approach represents an easy, fast, and effective characterization of arbitrary‐order mutual coupling. It can find applications in the modeling of mutual coupling between any circuit elements and building blocks such as antennas, resonators, and even small discontinuities, and it promises to be helpful for the analysis and iterative design of microwave circuits and antenna arrays. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

基于布尔过程论的层次化延时分析方法

芯片设计的日益复杂化和高速化对电路精确的定时特性提出了越来越高的要求。电路的延时不仅与电路的拓扑结构有关,而且还与电路的逻辑功能及输入都有密切的关系。采用Boole过程论这种统一描述数字电路的逻辑行为和时变行为的代数形式作为理论基础,提出了波形多项式偏导的概念,并用之重新定义了敏化。用偏导定义的敏化改进了解析延时模型,基于最长可敏化通路的延时建立了电路模块或子电路的延时矩阵模型,由延时矩阵模型出发提出了一种精确的电路层次化延时分析方法。最后用实验验证了文中提出的延时分析方法的有效性。     

Development of a user friendly gate-level logic simulator

A design of a digital logic simulator is developed and presented. BASIC on an IBM Personal Computer using interactive graphics tools is employed to make the simulator easy to use. The simulator can handle gate level logic circuits, and can be used for both logic verification and fault testing.

Efficient and correct simulation in a user-friendly environment was the main design objective. Concepts of interactive computer graphics are extensively applied to enable the drawing of the circuit. Menu structures have been used to simplify the interaction of user and computer. The foundation has been laid for a simulator that uses pattern recognition for circuit data acquisition.

The simulator permits the verification of the logic of a circuit without fault. The design also includes provision for inserting delays and simulating to detect hazards. Test sequences to detect the presence of faults in the circuit can be generated using deductive simulation. The design provides a reliable basis for further research into logic simulation.     

Tabu search based circuit optimization

In this paper we address the problem of optimizing mixed CMOS/BiCMOS circuits. The problem, formulated as a constrained combinatorial optimization problem is addressed using a tabu search algorithm. Initially a random approach is adopted for selecting among available solutions. Further, as an alternative competing solution the concepts of simulated evolution are applied to classical tabu search (CTS). This allows for a stochastic criterion for selecting among available solutions as compared to the random approach of CTS. Only gates on the critical sensitizable paths are considered for optimization. Such a strategy leads to sizeable circuit speed improvement with minimum increase in the overall circuit capacitance. Compared to earlier approaches, the presented techniques produce circuits with remarkable increase in speed (greater than 20%) for very small increase in overall circuit capacitance (less than 3%).     

Simulation of the coupling of the external electromagnetic field to PCB traces in the SPICE simulator

In this article, a simple method of modeling and simulating electromagnetic field coupling to PCB in the SPICE simulator is presented. The method exploits two assumptions: quasi-TEM wave propagation along PCB traces and representation of an external electromagnetic noise by a plane wave. Under these assumptions, a model of electromagnetic field coupling to the PCB traces is created in the form of an active n-wire transmission line placed in an inhomogeneous (that is, three layers) medium. Next, using the method of successive approximations, an equivalent active n-port (described by means of scattering parameters) is found. This work results in formulas that express the external electromagnetic field in the form of current sources and the way they are simulated in SPICE. The method is illustrated with two examples. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 190–200, 2004.     

A novel electromagnetic bandgap design applied for suppression of printed circuit board electromagnetic radiation

In this article, a novel electromagnetic bandgap structure is applied to a high‐speed printed circuit board, where the proposed concept is to etch with traditional L‐bridge and extended connecting branches on the power plane. To investigate the electromagnetic characteristics of the proposed structure, its transmission performance is determined including an equivalent circuit to numerically predict the lower cutoff frequency. A near field electromagnetic interference measurement is carried out compared to a reference board to investigate the simultaneous switching noise suppression ability.     

基于C8051F005单片机的飞机供电系统模拟器

介绍了某型号飞机电源系统模拟器的结构和设计原理,详细介绍了C8051F005单片机及其外围的模拟量输入输出电路、数字量输入输出电路和供电电路,并对系统的软件设计进行了阐述,实验证明此模拟器实时性好,稳定性高,能满足系统要求。     

Integrated optimization design for high-speed three-axis actuator in optical pickup

Super-multi DVD drives are assumed to have the largest market share in the near future because of their high compatibility with all kinds of DVD/CD formats and high recording-reading speed at low cost. In this paper, we present a three-axis actuator used in a super-multi drive with a special magnetic circuit, consisting of symmetric driving coils and permanent magnets with proper placement. At first, the lens holder is optimized with sensitivity method to improve the flexible vibration modes in structure parts. Then, electromagnetic circuits are designed and optimized by Taguchi method and response surface methodology (RSM). Consequently, the final model is fabricated and tested by laser vibrometer system. The results verify the proposed actuator and the integrated design methods.     

Leakage current estimation of CMOS circuit with stack effect

Leakage current of CMOS circuit increases dramatically with the technology scaling down and has become a critical issue of high performance system. Subthreshold, gate and reverse biased junction band-to-band tunneling (BTBT) leakages are considered three main determinants of total leakage current. Up to now, how to accurately estimate leakage current of large-scale circuits within endurable time remains unsolved, even though accurate leakage models have been widely discussed. In this paper, the authors first dip into the stack effect of CMOS technology and propose a new simple gate-level leakage current model. Then, a table-lookup based total leakage current simulator is built up according to the model. To validate the simulator, accurate leakage current is simulated at circuit level using popular simulator HSPICE for comparison. Some further studies such as maximum leakage current estimation, minimum leakage current generation and a high-level average leakage current macromodel are introduced in detail. Experiments on ISCAS85 and ISCAS89 benchmarks demonstrate that the two proposed leakage current estimation methods are very accurate and efficient.     

一种新型四相控制开关电源拓扑和控制方法

多相控制技术能满足高频低压大电流输出的应用场合对开关电源可靠性、效率和功率密度日益提高的要求。为了实现并联电路冗余和高精度均流控制,根据在不同并联模式下的多相控制开关电源的不同特点,该文提出了一种新型四相控制开关电源拓扑。针对新型电源的拓扑,采用了增强型V^2（双压）控制方法。新型开关电源的工作频率得到了大幅提高,有利于减小功率损耗和电源的体积、重量。增强型V^2控制方法除了有响应速度快和控制精度高的优点,相对于V^2控制方法更解决了并联电路中均流控制的问题。最后运用PSPICE仿真验证了结果。     

Nonlinear circuit analysis using the method of harmonic balance—a review of the art. II. Advanced concepts

The harmonic balance method is a technique for the numerical solution of nonlinear analog circuits operating in a periodic, or quasi-periodic, steady-state regime. The method can be used to efficiently derive the continuous-wave response of numerous nonlinear microwave components including amplifiers, mixers, and oscillators. Its efficiency derives from imposing a predetermined steady-state form for the circuit response onto the nonlinear equations representing the network, and solving for the set of unknown coefficients in the response equation. Its attractiveness for nonlinear microwave applications results from its speed and ability to simply represent the dispersive, distributed elements that are common at high frequencies. The last decade has seen the development and application of harmonic balance techniques to model analog circuits, particularly microwave circuits. The first part of this article reviewed the fundamental achievements made during this time. In this part, the extension of the method to quasi-periodic regimes, optimization analysis, oscillator analysis, studies of various convergence strategies, and practical applications are discussed. A critical assessment of the various types of harmonic balance techniques is given. Examples of designs which have been modeled using the harmonic balance technique and built both in hybrid and MMIC form are presented.