Prediction of RF ground voltage drop using a fullwave approach

The behavior of reradiated fields from PCBs, with the radar cross section being the main parameter of interest is investigated in this work. A rigorous approach to predict radiation from PCBs in a GTEM cell is presented. The analysis is based upon the use of the reciprocity theorem in combination with the method of moment applied to the scattered field. Thus, yielding a generalized impedance matrix, whose determinant represents the characteristic polynomial of the scattering system. The effectiveness of the method is demonstrated by investigating some canonical circuit configurations and structures illustrating sources of fundamental EMI mechanism. The validity and the accuracy of the analysis becomes obvious in view of the one-to- one correlation with measurements. I. INTRODUCTION Printed-Circuits Boards (PCB) are of overriding importance in modern microelectronics where they undergo a continu- ous package complexity. Multilayer structures, split reference planes, various interconnects like bends, vias, etc. and trace circuit configurations in form of rectangular/circular loop, bent wire, linear dipoles, etc., are commonly mounted and present on hihgly integrated PCBs. These structures have led to an upsurge of interest in the analysis of the possible elec- tromagnetic interference (EMI) since they are often sources of unintentional radiated emission which can alter the EMC performance of real PCBs. Especially, in presence of an RLC- circuit, high-speed signals routed on the board may carry over resonances. These resonances tend, on their own, to carry interferences over much longer distances, which can not be predicted by field or gavanic coupling. The behavior of the reradiated field, with the PCB radar cross section (RCS) being the main parameter of interest, is therefore a good figure of merit in diagnosing radiation problems on the board. This paper addresses these particular points. Especially, it provides a rigorous approach to predict radiation from PCBs in a Giagahertz transverse electromagnetic (GTEM) cell. The analysis is based upon the use of the reciprocity theorem in combination with the application of the method of moment (MoM) to the scattered field yielding a generalized impedance matrix, whose determinant represents the characteristic poly- nomial of the scattering systems. After deriving an expression for the RCS in the next section, the generalized impedance matrix is evaluated for arbitrar- ily shaped wire radiating elements with a conducting plane reflector (section III). The real-axis method characterized by Sommerfeld-type integrals and moment-method solutions (1)- (3) is used to calculate elements of the impedance matrices. The effectiveness of the method is demonstrated by inves- tigating some canonical circuit configurations and structures illustrating sources of fundamental EMI mechanism (section IV). The validity and the accuracy of the analysis become ob- vious in view of the one to one correlation with measurements (section V).

This paper discusses the application of the so-called thin sheet approximation (TSA) for dielectric coatings to the calculation of the 3D coupling of printed circuit boards (PCBs) using the method of moments (MoM). By extending the TSA to open structures, the volume currents in the dielectric layer can be described by surface currents on the PEC conductor and the problem can be reduced to single current layers. As a consequence, the number of unknowns is reduced drastically. In order to verify the TSA approach and its accuracy and to investigate the influence of the layer and conductor thickness of coated PCBs, comparisons to results obtained by the classical MoM computation and a finite element (FEM) solver are given.

Numerical analysis of crosstalk between two traces in a printed circuit board is presented using the method of moments (MoM). In the high-frequency range, the attenuation constant is neglected in the theory for its very small values. The width of the trace is accurately determined for the trace impedance of 50 ohm from the charge distribution on the traces without using an approximated empirical formula. Line capacitances are determined from the total charge on the conductors and the line potentials. The coupling capacitance and inductance are determined from in-phase and out-of-phase excitations between the traces. Crosstalk interference is calculated from these coupling parameters. Results of crosstalk obtained from the above technique are verified by comparing with those obtained from four other methods: (1) Ansoft HFSS software tool, (2) even mode and odd mode analysis, (3) empirical formulae of parasitic elements, and (4) measurements using a vector network analyser. All the results agreed well. The results obtained by using the method of moment technique are more stable, reliable, and accurate among all the described different methods. This paper shows that the analytical method using MoM is a useful tool for predicting crosstalk interference in PCB without using expensive simulation software.

Based on a full-wave equivalent circuit approach, one could easily predict the potential difference of a signal return conductor on a printed circuit board (PCB) as well as the common-mode (CM) current on any conductor that attached to the PCB. With the predicted ground bounce and CM current, their relationsip is investigated.

A radio frequency (RF) front-end module at 5 GHz has been designed and implemented in a conventional printed circuit board (PCB). The module consists of two switches, two bandpass filters, a balun, a low noise amplifier and a power amplifier. Distributed components and sub-circuits based upon the transmission line theory have been utilized for the module design. All the sub-circuits and the entire module have been evaluated by both simulation and measurements. It is shown that RF modules at 5 GHz can be integrated in a PCB utilizing a conventional PCB process. This module integration technique provides not only low cost but also high performance because of the elimination of parasitics associated with lumped components in a conventional design

Analysis of field coupling and emissions from printed circuit boards (PCBs) is important for assessment of the immunity of the PCB to external radiation. Immunity of electronic systems is now tightly regulated in consumer markets. This paper presents a procedure for the analysis of susceptibility of PCBs. The procedure identifies a finite set of source and field points to increase the efficiency of the numerical testing. Reciprocity is used to decrease the number of external source locations that need to be used in the field coupling analysis through performing a radiation analysis. The numerical analysis of the PCB is performed using the Method of Moments (MoM). Numerical examples for the application of method are included. Further examples of the overall procedure will be presented.

The frequency at the peak of electromagnetic radiation from a PCB (Printed Circuit Board) as a result of ground bounce is considered predictable from the frequency characteristics of the input impedance between the power supply and ground layer (below called the PCB impedance). However, the relationship is largely unknown. In this paper, the electromagnetic radiation of the PCB and the frequency spectrum of the PCB impedance are analyzed by the FDTD (Finite‐Difference Time‐Domain) method and their relational mechanism is studied by comparison with the measured values. It is found that the peak of the electromagnetic radiation appears at the frequency where the PCB is a minimum if the PCB is excited by a voltage source with an internal resistance sufficiently smaller than the PCB impedance, and that this peak is shifted toward the frequency at which the PCB impedance becomes a maximum if the internal resistance is increased. The radiation power ratio derived from the resistive components (called the resonant resistances) at two frequencies where the PCB impedance is maximum and minimum (resonant frequencies) mostly agrees with the ratio of the squares of the radiated electric field. Hence, the radiation peak frequencies of the PCB are determined both by the internal resistance of the excitation source and the resonant resistance of the PCB impedance. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(11): 30–38, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10209

Electromagnetic disturbances for vehicle-mounted radios can be caused mainly by conducted noise currents flowing out from vehicle-mounted multi-layer printed circuit boards (PCBs) to wire-harnesses. Using actual electronic equipment for vehicles, we previously showed that combining, not separating, the ground layer patterns of a digital circuit and an analog circuit is more advantageous to reduce the noise current outflow, while the mechanism remains unknown. In the present study, based on an idea that this mechanism should generate from a change in the amount of common return currents flowing to the ground, we measured noise current outflows from five types of simple PCBs having different ground patterns, which were validated from simulation with the method of moment. As a result, we could confirm that slits on a ground pattern allow conducted noise currents to flow out from PCBs, while the levels for the symmetric two slits ground types are smaller compared to the case for the asymmetric two slits ground types. The mechanism could be explained qualitatively from balanced conditions of an equivalent bridge circuit.

A complex modern embedded system using a multi-core Central Processing Unit (CPU) toward a compact integrated design in a single Printed Circuit Board (PCB). One of the biggest challenges of the design is to meet the Signal Integrity for high speed Double Data Rate 3 Synchronous Dynamic Random-Access Memory (DDR3) bus. A typical strategy to solve the challenge is the simulation on the computer, but this is not always an effective solution as has a gap between simulation software and practical PCB. The gap is correlated to localized changes in copper density within the PCB and characterization of heterogeneous materials in PCB that could lead to differences in the real PCB. The purpose of the research presents an analysis methodology to design DDR) memory interfaces in high speed embedded systems, related to Signal Integrity and the impact of copper density on PCB trace impedances to overcome these challenges. Moreover, the presented design methodology is also applied to the next generation DDR as well as other styles of CPU.

compatibility (EMC) is an engineering discipline often identified as black magic. This belief exists because the fundamental mechanisms on how radio frequency (RF) energy is developed within a printed circuit board (PCB) is not well understood by practicing engineers. Rigorous mathematical analysis is not required to design a PCB. Using basic EMC theory and converting complex concepts into simple analogies helps engineers understand the mitigation process that deters EMC events from occurring. This user-friendly reference covers a broad spectrum of information never before published, and is as fluid and comprehensive as the first edition. The simplified approach to PCB design and layout is based on real-life experience, training, and knowledge. Printed Circuit Board Techniques for EMC Compliance, Second Edition will help prevent the emission or reception of unwanted RF energy generated by components and interconnects, thus achieving acceptable levels of EMC for electrical equipment. It prepares one for complying with stringent domestic and international regulatory requirements. Also, it teaches how to solve complex problems with a minimal amount of theory and math. Essential topics discussed include: * Introduction to EMC * Interconnects and I/O * PCB basics * Electrostatic discharge protection * Bypassing and decoupling * Backplanes-Ribbon Cables-Daughter Cards * Clock Circuits-Trace Routing-Terminations * Miscellaneous design techniques This rules-driven book-formatted for quick access and cross-reference-is ideal for electrical and EMC engineers, consultants, technicians, and PCB designers regardless of experience or educational background. Sponsored by: IEEE Electromagnetic Compatibility Society

The present paper provides a review of the main concepts and principles involved in mixed PCBs (printed circuit board) design for electronic devices with mixed technologies, i.e. analog, RF (radio frequency) and digital components within the same PCB, such as characteristic impedance, layer stack-up and shielding.

The present paper provides an introduction to the concepts and hints used to layout PCBs (Printed Circuit Boards) with good SI (Signal Integrity) and EMI (Electromagnetic Interference) control when designing RF (Radio Frequency), analog and digital electronic circuits, within the same PCB. This document also analyses the problem of getting good SI and EMI performance in dense populated PCBs with mixed technologies whenever interactions between technologies could not be avoided.

A hybrid FEM/MOM method was used to solve a canonical printed circuit board (PCB) problem. The PCB is populated with three traces. One is a signal line and the other two are I/O lines that extend beyond the boundary of the board. The finite element method (FEM) was used to model the fields in the volume around the on-board trace. The method of moments (MOM) was employed to model the equivalent surface currents on the board and the current on the off-board traces. The FEM and MOM equations were coupled by forcing the continuity of tangential fields on the dielectric boundary. An efficient meshing strategy was employed to reduce the memory requirements. The major contributors to far fields in different frequency bands and for different polarizations are discussed.

Recently, PCB(Printed Circuit Board) is required more high precision, function and miniaturization for advanced electronics, display, semiconductor and packaging, etc. and this complex PCB needs cutting, repair, trimming and structuring, etc. So, we make complex machine that is possible this all PCB processing and test PCB material processing using developed machine. This machine consists of UV nano-second pulse laser, power controller(self-developments), probe stage for trimming, auto focusing and scanner. The power controller is possible to monitor real-time power and adjust precision laser power. Using various parameters such as laser power, scanning speed, repetition rate and pulsed overlaps can obtain for process result having high precision and speed.

This paper provides an introduction about embedded capacitance technology and its implementation on printed circuit board (PCB). The advantages of implementing embedded decoupling capacitance in compact PCB with high speed signal transmission are also explained. The advantages in terms of power and signal integrity are discussed in detail by performing analysis in 2 phases. In phase one, the computation of power distribution network (PDN) impedance of the conventional PCB with discrete decoupling capacitors and the PCB with embedded decoupling capacitance is performed. Meanwhile in phase two, co-analysis of power and signal integrity (PI/SI) on test cases with decoupling conditions mentioned in phase one is conducted to observe the power rail noise and quality of signal transmission. The analysis results are further discussed in the later section of this paper.