Ricardo Jauregui

Transient FDTD simulation validation

In computational electromagnetic simulations, most validation methods have been developed until now to be used in the frequency domain. However, the EMC analysis of the systems in the frequency domain many times is not enough to evaluate the immunity of current communication devices. Based on several studies, in this paper we propose an alternative method of validation of the transients in time domain allowing a rapid and objective quantification of the simulations results.

Analyzing Transient Phenomena in the Time Domain Using the Feature Selective Validation (FSV) Method

The increasing application of simulation tools to increasingly complex problems makes the use of validation tools essential to improve confidence in the veracity of those simulation results. IEEE Standard 1597.1 is the first true standard for the validation of computational electromagnetics method. This standard uses the feature selective validation (FSV) method as the key quantification tool. However, despite its many advantages, there have been some interesting issues surrounding the validation of transients. This paper presents a new approach to the validation of a set of generally representative transient types using the FSV method and shows how the previously experienced limitations can be overcome. In order to analyze the main parameters associated with transient comparison, a survey which included 20 experts was conducted. This information was used to identify the significant regions that need to be taken into account in the transient comparison. Finally, using the statistics obtained by the experts, a new solution was defined and its improvement over the existing approach was demonstrated.

The Role of Uncertainty in the Feature Selective Validation (FSV) Method

This paper presents a method of taking into account the uncertainty when the Feature Selective Validation (FSV) method is used. Nowadays, there is no doubt about the important role played by the FSV to do an objective process of validation. However, until now the uncertainty has not been considered in the validation process. This paper presents an alternative way to calculate the possible value of FSV, when the uncertainty is contemplated. We show the importance of this technique when defining the validation criteria for the computational electromagnetics method. Finally, in order to show the application and the importance of the method, a real case considering the test lab measurement uncertainty is analyzed.

A Review on the Drawbacks and Enhancement Opportunities of the Feature Selective Validation

The growing application of simulation tools to increasingly complex problems makes the use of validation techniques essential to improve confidence in the veracity of those simulation results. The feature selective validation (FSV) method is widely used today, because of its versatility and simplicity. However, despite its many advantages, some problems have been identified in the standardized FSV method. Those drawbacks can produce misleading results for the validation process and constitutes enhancement opportunities for further research on FSV improvement. This paper presents a review that summarizes the major problems of the FSV and their possible solutions as a justification to reform the FSV method and also looking towards the forthcoming update of the standards IEEE 1957.1/2.

Improvement in the Definition of ODM for FSV

It has been found that the feature-selective validation (FSV) method may demonstrate inconsistencies in the results when applied to the comparison of zero-crossing datasets. This type of data is typical of time-domain-based electromagnetic compatibility validation. This paper investigates the source of this inconsistency and proposes a solution. The reason was investigated using a set of typical transient data, which was related to the derivation of the formulas of FSV. It is demonstrated that the problem can be alleviated by enhancing the definition of the offset difference measure. The resulting enhanced performance of FSV is assessed by comparing the results with visual assessment. It is demonstrated that the improvement increases the agreement between FSV prediction and visual assessment. Meanwhile, this modification has a very limited effect on the comparison of other data structures which do not cross the axis.

Transient perturbation analysis in digital radio

This paper presents a new simulation methodology to study the effect of radiated transient disturbances on digital communication systems. The procedure is divided in two stages. In the first one, FDTD numerical simulation is used to determine the transient levels coupled to the antennas. In the second stage, these levels are analyzed by means of a signal processing simulation software to determine the degradation caused in the system. The procedure is applied to a DAB system in car when a radiated interference is generated by a transient in a vehicle cable. The results show that the amplitude of the radiated transient coupled signal is a key parameter, but it is also essential to take into account other parameters such as burst duration and frequency.

Characterization of EMI filters based on metamaterials

This paper analyzes the behavior of EMI filters based on metamaterials. The filters are developed by means of sub-wavelength resonators and designed to have notch-type attenuation in the 2.45 GHz band. Two types of filters based on SRR and CSRR rings are presented. The simulated responses by MoM and FDTD are compared with the measurement data obtained from the developed prototypes.

Validation of low-level, high-frequency transient FDTD simulation with radiated field measurements

Validation of numerical simulation results for low-level, high-frequency transient radiated EMC signals is difficult because of the limitations of time domain measurement instruments. A measurement method combining the sensitivity of a RF spectrum analyzer and the time domain abilities of a digitizing oscilloscope is used to validate FDTD simulations of a fast transient coupled between two antennas inside a car.

Transient Electromagnetic Field Computation in Automotive Environments using FDTD

Numerical electromagnetic computation at high frequencies in automotive environments is a challenging problem because of the dimensions of the problem compared to the wavelength. Results obtained so far have been presented in the frequency domain. We are presenting comparisons between calculated and measured transient waveforms, so in the time domain, by using a model of a realistic car body frame. Results are presented for different settings in the simulation grid parameters. The agreement of the signals in time and also in the frequency domain allows us to conclude that such computations are feasible up to the GHz frequency band and using modest computation resources.

Feature Selective Normalized Mutual Information Index for the validation of computational electromagnetics

An important concern in the validation of computational electromagnetics (CEM) is to incorporate quantitative indicators in order to perform conclusive comparisons between model predictions with respect to a reference expected response, such as data obtained from measurements, closed-form equations references or standard reference problems values. Besides, the aforementioned index must be qualitatively interpreted using established and objective criteria, mimicking the perception of individuals or teams of expert engineers and aiding them in the interpretation process. So far, this problem has been addressed by the standardized Feature Selective Validation (FSV) method which has become the most widespread technique in the validation of CEM. Nonetheless, the FSV has some drawbacks which have driven subsequent and non consolidated enhancements proposed to improve its performance under specific situations. This paper proposes a global and normalized mutual information based index that includes feature selective considerations as an alternative to evaluate and compare datasets involved in the validation of CEM. Finally, three numerical examples are developed using the presented methodology and the results are compared with the overall indicator for the amplitude and the feature measures obtained using the FSV. The results suggest that the proposed index is able to provide intuitive, consistent and compressive interpretation about the global results of the validation process. Nevertheless, research must be continued in order to refine the proposed method and testing its complete range of applicability and suitability.