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20 H规则作为PCB典型布线规则,随着传输信号工作频率逐步提高,其越来越被PCB设计人员采用以用来减少EMI问题。当然,PCB制造人员无法模拟20 H规则的EMI但须控制特性阻抗,故本文试图首次阐述20 H规则对特性阻抗控制的影响,并通过相关试验与量产过程进行证明。 相似文献
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Wide-band undesired electromagnetic noise near electronic systems, which includes small noise source like the printed circuit board (PCB), is a current problem in the field of electromagnetic interference. However, the estimation method for the electromagnetic noise near a system under test has not been established. This paper proposes a newly developed estimation method of the electromagnetic noise for a wide area, from near to far field, using the finite difference time-domain (FDTD) method. The proposed FDTD simulation method is an estimation technique for near to far field with multiple analysis spaces (MAS). The MAS has an internal analysis space (IAS) and an external analysis space (EAS). The analysis near a radiation source can be calculated in the IAS. The EAS is the outside space from IAS, which is for calculation of the far field. It is expected that the proposed FDTD method by MAS (FDTD-MAS) decrease in the calculation cost in terms of computational time and memory costs, especially for estimation of radiation from PCB. The principle procedure of the FDTD-MAS method is described in the first part of this paper. As example of advantages of the calculation and confirmation of the calculation accuracy, the electric field distributions radiated from a 1-GHz half-wavelength dipole antenna in an IAS of 0.3/spl times/0.3 m/sup 2/ area and an EAS of 7/spl times/7 m/sup 2/ area are used as examples. When the cell size ratio of IAS to EAS is changed from 6 to 20, the FDTD and theoretical values show good agreement. It is indicated that the FDTD-MAS simulation method is one of the most powerful tools for the estimation of electromagnetic noise from near field to far field from small and thin source. 相似文献
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目前,时域有限差分方法(Finite Difference Time Domain,FDTD)在电磁数值计算中已获得了广泛应用。对许多复杂电磁问题,FDTD 算法需要耗费巨大的计算机计算时间和存储空间,这成为FDTD 方法亟待解决的难题。本文提出了应用基于消息传递(Message Passing)方式实现FDTD 的并行算法。并对基于MPI 不同通信方式的并行FDTD 进行了效
率比较。采用MPI2.0 单边通信方式中的put 操作和主动对象同步(PSCW)方式,在一套16 个节点的Beowulf 型网络并行计算机系统上,实现了三维FDTD 并行程序,获得了较高的加速比和并行效率。 相似文献
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Common-mode current due to a trace near a PCB edge and its suppression by a guard band 总被引:1,自引:0,他引:1
Kayano Y. Tanaka M. Drewniak J.L. Inoue H. 《Electromagnetic Compatibility, IEEE Transactions on》2004,46(1):46-53
The common-mode (CM) current due to a trace near a printed circuit board (PCB) edge, and its suppression by a guard band have been studied experimentally and with finite-difference time-domain (FDTD) modeling. As the guard band, copper tape is connected along the entire edge of the ground plane. First, a PCB electromagnetic interference (EMI) coupling path that results from the nonzero impedance of the PCB ground plane is discussed. As the trace is moved closer to the PCB edge, the CM current increases. Then, the effect of the guard band on the CM current is detailed. A guard band parallel to and near a trace is most effective in suppressing the CM current. The cross-sectional magnetic field distribution at center of the PCB with and without the guard band is also calculated with FDTD modeling. The guard band decreases the magnetic field distributed on the reverse side of a PCB. These results indicate the guard band is effective in suppressing CM current. Finally, an empirical formula to quantify the relationship between the position of a trace and CM current for the case with a guard band is proposed. Calculated results using the empirical formula and FDTD modeling are in good agreement, which indicates this empirical formula should be useful for developing EMI design guidelines. 相似文献
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本文应用时域有限差分法(FDTD)和离散傅立叶变换(DFT)分析和计算了一种开口式同轴加热装置内部谐振场和外部辐射场,给出了使用两种不同激励源以及是否使用扼流槽后的场的结果。测量结果显示了这处方法的准确性。这种可移动的开口式加热器可以方便地提升对材料进行热处理的温度。 相似文献
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This paper presents a comprehensive modelling methodology for the electromagnetic immunity of integrated circuits (ICs) to direct power injection (DPI). The aim of this study is to predict the susceptibility of ICs by the means of simulations performed on an appropriate electrical model of different integrated logic cores located in the same die. These cores are identical from a functional point of view, but differ by their design strategies. The simulation model includes the whole measurement setup as well as the integrated circuit under test, its environment (PCB, power supply) and the substrate model of each logic core. Simulation results and comparisons with measurement results demonstrate the validity of the suggested model. Moreover, they highlight the interest of the aforementioned protection strategies against electromagnetic disturbances. 相似文献
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基于时域有限差分(finite-difference time-domain,FDTD)法和传输线方程,并结合插值技术,研究了一种高效的时域混合算法,能够快速模拟电磁波照射自由空间和屏蔽腔内双导体传输线的电磁耦合,并实现空间电磁场与双导线瞬态响应的同步计算.该算法先采用FDTD方法模拟双导线周围空间的电磁场分布,结合插值技术构建适用于双导线电磁耦合的传输线方程,再采用FDTD的中心差分格式进行离散,从而求解得到传输线和端接负载上的瞬态响应.同时,分析双导线间距对其电磁耦合的影响,掌握其耦合规律.通过相应数值算例的模拟,并与FDTD方法进行对比,验证了该时域混合算法的正确性和高效性. 相似文献
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In this short paper, we present two methods: Quasi-images formula and finite-difference time-domain (FDTD) method to evaluate the electromagnetic fields very close to lightning channel, which are applicable for poorly conducting ground case, and the numerical results are consistent with each other. Moreover, the vertical electric fields at 15 m obtained by the two proposed methods is in good agreement with the measured result, and the horizontal electric field at a distance of 100 m above finely conducting ground obtained by the FDTD method is identical to the field obtained by accurate Cooray-Rubinstein approximation. With the proposed quasi-images formula, the effects of electrical dispersion of the ground on the lightning generated electromagnetic fields are analyzed and some significant results are obtained. 相似文献
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Development of accurate schemes is a technical issue related to calculation of electromagnetic fields. This study uses constrained interpolation profile (CIP) method to analyze electromagnetic fields created by line current. This is a novel method proposed by Yabe. Comparison of results obtained using finite difference time domain (FDTD) analysis and CIP analysis indicates that CIP analysis provides higher accuracy using identical discretization. In addition, given the same level of accuracy, CIP analysis requires less memory and less calculation time 相似文献
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R. S. Chen Edward K. N. Yung Fei Ji W. B. Dou 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(5):813-828
In this paper, a novel microstrip circulator with a magnetized ferrite sphere is proposed for various millimeter wave communications. A three-dimensional Finite-Difference Time-Domain (FDTD) approach for the analysis of this ferrite sphere based microstrip circulator is first presented. The electromagnetic fields inside the ferrite junction are calculated using special updating equations derived from the equation of motion of the magnetization vector and Maxwell's curl equations in consistency. Frequency dependent insertion loss, isolation and reflection loss of circulator are calculated over a wide band of frequencies with a single FDTD run. Experimental results at Ka band are presented and compared with theoretical simulations. As a result, a good agreement is found between them. 相似文献
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Popovic M. Hagness S.C. Taflove A. 《IEEE transactions on bio-medical engineering》1998,45(8):1067-1076
Transverse electromagnetic (TEM) cells can be used for exposing biological culture specimens to electromagnetic fields and observing possible anomalous effects. The uniformity of field exposure is critical to quantifying the biological response versus the electromagnetic dose. Standing waves and other electromagnetic field nonuniformities can cause nonuniform exposure. This paper reports the results of high-resolution three-dimensional finite-difference time-domain (FDTD) simulations of a complete TEM cell designed for operation at 837 MHz. Several different cases were studied in which the number of culture dishes, the depth of the culture liquid, and the orientation of the culture dishes were varied. Further, the effect of the culture-dish glass bottom thickness and the meniscus of the liquid medium were examined. The FDTD results show that there is a significant nonuniform field and specific absorption rate (SAR) distribution within the culture medium for each case examined. Hence, biological dose-response experiments using the TEM cell should account for the possibility of strong localized SAR peaking in the culture media to provide useful data in setting exposure standards for wireless communications 相似文献
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An Ping Zhao 《Antennas and Propagation, IEEE Transactions on》2004,52(7):1630-1637
In this paper, the influence of the aspect ratio of Yee's unit cell on the numerical dispersion errors [in terms of the physical phase-velocity error (PVE) and the velocity-anisotropy error (VAE)] of two-dimensional (2-D) finite-difference time-domain (FDTD) and three-dimensional (3-D) FDTD methods is comprehensively investigated. Numerical results reveal that, for a fixed mesh resolution, the physical PVE and the VAE of both the 2-D and 3-D FDTD methods converge to certain limits for higher aspect ratio. Most importantly, it is found for the first time that for the 2-D and 3-D cases the converged dispersion errors (i.e., the limits) are, respectively, about 2.0 and 1.5 times of the corresponding square and cubic unit cells; and the validity of the above theoretical prediction is verified through numerical tests. The investigation carried out in this paper certainly confirms, from the numerical dispersion point of view, that very accurate numerical results can still be obtained even when the aspect ratio of the cells is higher. Consequently, it gives design engineers more freedom and confidence to use the FDTD methods, especially when the aspect ratio of the cells has to be greatly adjusted due to the special requirement of structures under study. 相似文献
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Susceptibility characterization of a cavity with an aperture by using slowly rotating EM fields: FDTD analysis and measurements 总被引:1,自引:0,他引:1
Murano K. Sanpei T. Fengchao Xiao Chen Wang Kami Y. Drewniak J.L. 《Electromagnetic Compatibility, IEEE Transactions on》2004,46(2):169-177
This paper describes the evaluation of the susceptibility of a cavity with an aperture using the finite-difference time-domain (FDTD) method and experimentally. To reduce the computing time, the FDTD method is used for the radiation from the cavity and the susceptibility is obtained by using the reciprocity theorem. The cavity used here is modeled after a full-tower desktop enclosure with a 3.5-in bay. The susceptibility characteristics are evaluated by measuring outputs of a monopole antenna and transmission lines installed in the cavity. The susceptibility characteristics, using a three-dimensional (3-D) map, are studied from the computed and the measured results by applying slowly rotating electromagnetic fields to the cavity on a turntable. Measured and modeled results are in good agreement, indicating the merits of the proposed approach for susceptibility/immunity evaluation. Moreover, some discussions are made to check the susceptibility mechanism. 相似文献
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Thomas D.W.P. Denton A.C. Konefal T. Benson T. Christopoulos C. Dawson J.E. Marvin A. Porter S.J. Sewell P. 《Electromagnetic Compatibility, IEEE Transactions on》2001,43(2):161-169
We examine the extension of a simple and versatile model of the electromagnetic fields in an equipment enclosure with an aperture to include the effects of loading the enclosure with conducting planes or printed circuit board structures (PCB). Modeling results are compared with experimental measurements of the shielding effectiveness in a cuboidal enclosure loaded with both grounded and ungrounded conducting planes and/or PCBs with a range of grounded and ungrounded tracks. Measurement results are compared with full electromagnetic simulations and the simple model to demonstrate the accuracy and range of validity of the simple model 相似文献
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运用具体算例,证明新型的电磁场数值计算方法———有限公式方法的正确性。运用有限公式方法,又称元胞法,对电磁波的传播过程,包括正弦电磁波在自由空间和介质空间中的传播过程,进行了二维的仿真,并与时域有限差分法的仿真进行了比较。计算结果表明,与目前数值计算方法相比,在保持同等计算精度的前提下,新方法在计算规模、计算效率等方面,具有明显的优势。计算结果证明:元胞法是正确的,同时也是高效的,他提供了一个新的计算电磁场的思路。 相似文献
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