Development of next generation FSV tools and standards

Predicting the High Intensity Radiated Field (HIRF) coupling in complex system is highly required in the aeronautic industry, which can be performed by electromagnetic simulation. But the validation of electromagnetic simulation is a difficult issue which needs proper flowchart and validation methods. In this paper, the numerical simulation by the parallel Finite-Difference Time-Domain (FDTD) method is validated on a simplify model of a metallic case with apertures under the HIRF environment. Concretely, the uncertainty quantification analysis on the input parameter of incident angles is carried out for the electric field in the center of the model with the method of nonintrusive polynomial chaos (NIPC). Based on this, the feature selective validation (FSV) is performed to quantify the comparison of the experimental data and the best simulation estimate. And the results obtained from the FSV method provide a high reliability for the numerical simulation.

The Feature Selective Validation (FSV) method is currently the only technique included in Standards that is specifically directed at quantifying the comparison of computational electromagnetics with a reference as part of a programme of validation. Histogram representation of the Difference Measures in FSV is a key aspect of the way in which the comparison data is represented. The current six categories (or bins) were introduced for convenience and to allow direct comparison with visual assessment as part of the verification of FSV performance. While approaches based on continuous density functions are being developed to enable FSV to act as an intermediate step between the original data and statistical analysis, the use of histogram-based representation remains a useful and computationally simple approach. This paper investigates the optimization of the histograms used in FSV.

This 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.

Objective validation and ranking of measurements and simulations may be done by methods, such as FSV (Feature Selective Validation). In this paper, FSV is used to compare two EMC-measurement results. Due to the noisy nature of this type of data, the FSV results are corrupted. The reasons are discussed and solutions are proposed to make FSV feasible in a broader area of applications. The final solution is a combination of denoising the data and changing the weight of the data to be in accordance with our visual interpretation.

The use of Ethernet cables is a vital, if under- discussed element of the infrastructure for the internet of things (IOT). While there are many cable types on the market, one worrying trend is the wide availability of copper clad aluminum (CCA) cables, which are widely considered unsuitable for infrastructure deployment. The availability of these copper clad aluminum (CCA) cables frequently disguised as compliant Ethernet communication cables calls for a method of assessing their performance, as this is crucial to ensuring quality of service delivery. This paper presents a method of analyzing the measured return loss and impedance profile due to handling stress. In this research, four Ethernet cables of which one of them was copper CCA cable were subjected to three rounds of coiling and uncoiling tests to represent stress from handling during installation. The Feature Selective Validation (FSV) method and Kolmogorov-Smirnov (KS) tests were used to quantify the variations between the tests. The results indicate that the CCA cable has the lowest resilience to physical stress with high potential for degradation.

The Feature Selective Validation (FSV) method has demonstrated a number of advantages over alternative assessment methods for validation of computational electromagnetics. For example, the availability of diagnostic information and the ability to mirror human perception. However, the FSV is a heuristically based technique and, in order to have confidence in the method itself, an understanding of how the output varies as the internal coefficients vary is important. The first, important, step in FSV is to filter the original signals into ‘low’ and ‘high’ transform portions, and this paper looks at the effect of varying the coefficients associated with this operation. It supports that the current partitioning is optimum but notes the areas where substantial care is needed in selection of the parameters.

To accurately predict High Intensity Radiated Field (HIRF) effects in various systems is highly required for most commercial as well as defense applications, which is mainly based on electromagnetic simulation. Further, the validation of the simulated HIRF effects at different levels is also required. However, it is often difficult and needs some appropriate techniques and facilities. Here, in-house developed parallel Finite-Difference Time-Domain (FDTD) solver is at first employed for simulating the HIRF effects of two metallic cases with multiple slots and apertures, which is carried out on a high performance computer with tens of thousands of processors. The uncertainty analysis of the incident plane wave angle related to the electric field distribution in the metallic cases is finished with the help of non-intrusive polynomial chaos (NIPC) method, and the feature selective validation (FSV) is performed to quantify the difference between the measured and simulated field results. It is shown that the results obtained from the FSV method provide high reliability and confidence for our numerical characterization of HIRF effects in the metallic cases and even other complex structures.

The authors' teaching experiences with numerical techniques in computational electromagnetics are described. Course descriptions and objectives are discussed, as well as their relationship to engineering practice.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A numerical analysis technique is demonstrated for the measurement of the shielding effectiveness (SE) of a conducting box cavity with apertures based on the use of a vibrating intrinsic reverberation chamber (VIRC) with the nested chamber approach. VIRC generates a multipath electromagnetic environment and can measure the SE for various polarizations and angles of incidence compared with the conventional plane-wave excitation method. The finite-difference time-domain method is applied to model a configuration for shielding effectiveness measurements and simulation of the configuration behavior. We investigated its usability based on the application of computational electromagnetics validation methods, such as the feature selective validation method, with reference results obtained with the conventional plane-wave excitation approach. The proposed VIRC numerical analysis platform used for the prediction of the SE of conducting cavities with apertures yields good outcomes even when the cavity exhibits a dominant resonance.

In this study, measurements inside the fuselage of an unmanned air vehicle (UAV) are conducted using a novel double-loaded loop probe. The characterization and evaluation of electromagnetic interference (EMI) within VAVs is a main research topic and requires state-of-the-art measurement methodologies. The developed probe is capable of obtaining accurate measurements as commercial reference E-Field broadband probes, introducing new advantages based on the reduction of the probe's electronics and the availability of the full time-domain data. Allowing to compute simultaneously the electric and the magnetic field and to measure high-amplitude electromagnetic pulses. The laser-probe works together with multi-channel full-time domain system computing the electromagnetic fields using an oscilloscope. Regarding the double-loaded loop probe characterization and validation, it has been carried out by comparing the results with different validation methods, like Feature Selective Validation Method and the Integrated Error against Logarithmic Frequency.

In this study, SPICE models of a multi‐antenna system for transmitting and receiving are proposed. The radiation fields at a given direction can be predicted by the transmitting SPICE model when the system is excited by a set of excitation sources. The receiving SPICE model can be used to calculate the coupling voltages on each antenna's load when the antenna system is illuminated by plane waves. The proposed modelling method for transmitting and receiving is a three‐step approach. In the first step, the radiation properties of the system are characterized by a minimal number of linearly independent radiation fields. Then, the transmitting and receiving equivalent models are established based on the radiation properties of the system. Finally, the equivalent models are approximated by rational functions and converted to SPICE models. Once these models have been established, the characteristic properties of the excitation signals can be changed arbitrarily without re‐establishing the models. Besides, both models can be incorporated with any terminations. The proposed SPICE models have been validated by a commercial full‐wave simulator. The feature selective validation method is used to quantify the models' results. Experiments are also conducted to validate the models.

This paper presents the author's teaching experiences on Numerical Techniques in Computational Electromagnetics for years, which includes course descriptions and objectives as well as the relation with engineering practice, etc.

Maxwell's equations are valid from the atomic to intergalactic length scales. Hence, features at various spatial or temporal scales may all be significant in electromagnetic (EM) problems of interest and may affect the results of multiscale modeling and simulation in computational electromagnetics (CEM). Solving electromagnetic problems that involve multiscale structures efficiently is challenging and is of growing interest in CEM. In recent decades, various approaches have been proposed for addressing the multiscale issue of electrically large problems. These methods can be roughly categorized into three types: the “geometry‐based,” “algebra‐based,” and “physics‐based” approaches. In this chapter, we introduce these three representative approaches for modeling multiscale problems in CEM: (1) the discontinuous Galerkin integral equation method (DGIE), which is a general domain decomposition framework for dealing with structures with mesh nonconformity; (2) the nested dissection accelerated H‐LU‐based fast direct solver for sparse matrices, which is used to construct effective preconditioners; and (3) the resistive sheet boundary condition‐based hybrid finite element‐boundary integral‐multilevel fast multipole algorithm (FE–BI–MLFMA), which can simulate electromagnetic field interactions with microwave‐absorbing honeycomb structures efficiently. After we present the formulation for each approach, we present examples to demonstrate its accuracy, capability, and performance.

Spatial Sampling and Interpolation Techniques in Computational Electromagnetics and Beyond

Recently, the authors have developed a number of new hierarchical and singular basis functions for field representation in two- and three-dimensional cells. Scalar and vector basis functions of both interpolatory and hierarchical kind together with some singular functions of the additive kind are discussed in detail, with several results, in a recent SciTech-IET book (R.D. Graglia and A.F. Peterson: Higher-order Techniques in Computational Electromagnetics), as well as in several other publications (for example, Graglia et al., IEEE TAP, vol. 61, pp. 3674–3692, Jul. 2013; IEEE TAP, vol. 62, pp 3632–3644, Jul. 2014; IEEE AWPL, vol. 13, pp 1701–1704, 2014, and in the special issue on "Finite Elements for Microwave Engineering," Electromagnetics, vol. 34, pp. 171–198, 2014).