1,720,961 research outputs found
Analysis of Radiated Emissions and Shielding Effectiveness for a metallic Enclosure with Shielding Springs
No full textThe high speed digital processing in modern electronic products has made more difficult the achievement of conformity about limits emissions. To verify the requirements of standards on these emissions the use of a metallic enclosure is often necessary: in this way the power radiated by the system is reduced. In this paper the radiated emissions and the shielding performance of a metallic rack with shielding springs are studied both by dedicated experiments and by simulations. An internal source represented by a loaded monopole antenna is used to investigate the radiated emissions at 3 meters from the box. A simplified model of the antenna is proposed in the numerical model and a good agreement over a frequency range up to 1 GHz is achieved between measured results and simulated results. Shielding Effectiveness is finally evaluated by means of two different kinds of source: 1) near field (internal source) and 2) far field (plane wave source)
Characterization of via holes discontinuities by means of numerical de-embedding
No full textA method for de-embedding scattering parameters S of via hole in multilayer printed circuit board is presented. By assuming that the via hole is not electromagnetically coupled with the adjacent lines, the scattering parameters are evaluated starting from the calculation of the transfer scattering matrix T obtained by a three dimensional full wave analysis of the test structure. The numerical approach used to obtain S and T parameters has been validated by comparison with results computed by other independent numerical methods and measurements. The proposed methodology allows a computational time saving and gives useful results for a CAD modeling of via hole discontinuities
Experimental validation of circuit models for bulk current injection (BCI) test on shielded coaxial cables
No full textIn order to validate, by means of measurement, some existing equivalent circuit models for the bulk current injection (BCI) test, a procedure is proposed to develop a proper circuit model for the injection clamp and the obtained circuit is introduced into the global one representing the overall cable. A suitable experimental set-up has been built and used. The measured induced voltages at the terminations of shielded coaxial cables are compared with those computed by the equivalent circuit. Upper and lower bounds are quantified in order to assess the order of accuracy of the predicted result
Characterization of interconnections performances for high speed digital boards: a frequency/time domain approach
No full textOn the modern digital equipments, characterized by continually increasing bandwidth requirements, the electrical properties of the printed circuit board interconnections affect and limit the quality of the traveling digital signals. This impacts on the electro-magnetic compatibility (EMC) performances of the system, because corrupted signals can easily increase the emissions from the system. Specific dielectric materials with low dielectric losses must be used for board manufacturing, in order to transmit digital signals with a high frequency harmonic content on longer distances. Consequently it is important to characterize, as function of the bit rate and the rise/fall time of the transmitted signal, the attenuation and deterministic jitter due to the dielectric material building up the board. To do this, one must separate (de-embed) from the measurements the effects of the adapters, used to connect the test board at the measuring instrument. The proposed de-embedding method uses a vector network analyzer with time domain option and only two traces, laid-out on the test board, with different lengths. The technique is validated by comparing the measured values with those coming from simulation
Issues in validation of complex-valued simulations for signal integrity analysis
No full textSignal integrity is concerned with such design issues as signal distortions caused by the effects of unmatched impedances, designed-in or parasitic capacitance/inductance and current return paths. It is of increasing importance because of the widespread use of high-speed digital circuitry and it is, therefore, a natural ally to EMC engineering. Circuit simulators, such as SPICE are widely used to analyze circuit performance, with significant success. More interest is being generated in mixed circuit/field models and full wave simulators in order to extend the applicability of signal integrity investigations. Like more established EMC studies, the validation of numerical models for this purpose is an issue to be addressed. This is particularly important, as the models may be required to compare complex valued data as opposed to only magnitude (or single valued data) as in the case of electric network characterization or equivalent circuit extraction. This paper considers how the feature selective validation (FSV) scheme can be applied to quantifying complex valued dat
Validation of Circuit Extraction Procedure by Means of Frequency and Time Domain Measurement
No full textAim of this paper is the validation in both frequency and time domain of the procedure to extract fully H-Spice compatible equivalent circuits of structures on printed circuit boards. The procedure is initiated by standard measurement of scattering parameters between 40 MHz to 20 GH. After the extraction of the equivalent circuit, the computed scattering parameters are compared with those measured. The same equivalent circuit is also used for transient analysis in order to compare TDR measurement and eye-pattern to a pseudo-random bit sequence with those coming from the simulation
Applications of FSV to EMC and SI data
No full textThis paper is concerned with the usability of the feature selective validation (FSV) method for comparing validation data. It addresses how it can help in the validation process and how the resulting validation data can be interpreted. It does this by considering two different case studies. The first considers two approaches to modeling electric fields in an equipment rack, and the second compares a Spice model for coupled circuit boards with a reference full wave model. The paper concludes that while the single value summary metrics are helpful to give an overall level of agreement, the detailed point-by-point information is very helpful when considering how to improve the models or measurements involved
A comparative study of PEEC circuit elements computation
No full textA key use of the PEEC method is the solution of combined electromagnetic and circuit problems as they occur in many situations in todays very large scale integrated circuits (VLSI) and systems. An important aspect of this approach is the fast and accurate computation of PEEC circuit matrix elements, the partial inductances and normalized coefficients of potential. Recently, fast multipole methods (FMM) have been applied to the PEEC method in the frequency domain as a way to speed up the solution. In this paper, we consider the fast evaluation of the PEEC circuit matrix elements by two different methods, a matrix version of the (FMM) PEEC method and a method, which we call the fast multi-function (FMF) PEEC approach. In this technique, the matrix coefficients are evaluated using analytical functions approximation of the coefficients in combination with a proper choice of numerical quadrature formulas
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