Ferran Silva

This article presents the hybridization of a multiconductor transmission line (MTL) solver, implemented using the finite-difference time-domain method, with the circuit solver ngspice to treat the terminations and interconnections of transmission lines. Transient analysis and crosstalk in MTLs have been widely studied, but the line terminations and the connections between lines are mostly restricted to lumped resistors, inductors and capacitors (RLC) components. However, realistic systems, such as power distribution or communication systems, typically involve more complex and a priori unknown connections. By integrating the MTL solver with a circuit solver, the proposed approach enables the inclusion of any component for which a circuit model can be written or already exists, i.e., dispersive elements, such as ferrites, and electronic components, such as diodes, amplifiers, or transistors. This capability makes it possible to simulate the MTL networks with complex, including nonlinear, terminations and interconnections modeled by circuits. The proposed method is validated through comparison with experimental laboratory measurements.

This article derives and validates a set of distance conversion factors for the magnetic field emissions limits in the frequency range from 9 kHz to 30 MHz, which are intended to be proposed for their inclusion in new electromagnetic compatibility standards. Simulation models based on loop-type electromagnetic field sources are employed to evaluate, using the method of moments, the changes in the amplitude of the H-field components along the measurement axes. An algorithm is developed to extract the H-field strengths normalized to the reference distance and then, through methods for optimal detection of changepoints, such a normalized curve is fitted to a piece-wise linear function that becomes the generalized distance conversion factor, presented in the form of simplified equations. The fitness of the model is checked through experiments carried out in representative locations, showing a very good agreement between measurement and simulations. The adequacy of the conversion factors and the problem around the equipment under test are also analyzed.

Performing in-situ radiated emissions measurements, that is, in locations different from a standard test site, can be a challenging task because of the high electromagnetic noise levels in the ambient. A harsh electromagnetic environment characterizes such sites, and it usually results in difficulties when discerning between emissions from the equipment under test and electromagnetic fields generated by surrounding devices. Moreover, communications signals from broadcasting services are generally significantly higher than the standard emission limits making it even harder to determine compliance. In this paper, we present different techniques leveraging the advantages of time-domain measurement systems to provide effective and practical solutions to mitigate ambient noise’s effect on radiated electromagnetic interference measurements. First, the test method used is described, and pragmatic considerations are given to ensure reliable and repeatable measurements. Multi-channel time-domain measurement systems are introduced as the fundamental tool for the proposed strategies. Subsequently, different study cases are evaluated with real test examples, highlighting several criteria intended to reduce the impact of ambient noise on the actual emissions measures produced by the equipment under test. Finally, a real application of those strategies for measuring a photovoltaic system is described. Overall, the methods employed and the main advantages of using full-time domain FFT-based receivers are reviewed. In addition, the possibility of incorporating this paper’s outcomes into forthcoming electromagnetic standards about in-situ radiated emission measurements is also debated.

The electromagnetic characterization of reaction wheels is crucial to comply with the demanding ac magnetic field cleanliness requirements of space science missions, thus, preventing interference on sensitive onboard instrumentation. Therefore, a complete assessment, including the measurement of the magnetic flux vector at different operational modes and under dynamic conditions, is proposed as a contribution beyond conventional testing methodologies. This article investigates the worst-case magnetic field emissions experimentally, using a test setup based on a multichannel acquisition and multidomain postprocessing system. The focus of the measurement campaign was on the low-frequency range (10 Hz–2 kHz). Moreover, capturing the B-field in the time-domain enabled further analysis, that is, complementary outputs for understanding the electromagnetic performance of the reaction wheel. As a result, we can relate the wheel rotation with the current and the magnetic fields, compute the field orientation, and evaluate in-band interference for the magnetic field.

The study of currents flowing through the fuselage of an airplane is of vital importance from the standpoint of electromagnetic compatibility due to their potential for causing severe failures on embedded systems. Direct lightning strikes can produce extremely high currents propagating through the fuselage panels. Such high currents are critical when flowing through mechanical joints, a point of complex analysis due to the existing electrical discontinuities. Consequently, understanding the propagation of these currents is vital for protecting avionics through improved joints not only from a structural standpoint but also from an electromagnetic perspective. In this paper, we propose designing and validating a Rogowski coil sensor to measure the current flux through the mechanical joints that attach different fuselage panels. This sensor is theoretically analyzed, and a circuit model is provided. Then, a PCB Rogowski coil is designed and manufactured for measuring high-intensity pulsed currents with a bandwidth of 10 MHz. Subsequently, the probe is characterized through its S-parameters. Next, its equivalent lumped-element circuit is extracted and simulated for validating the sensor’s transient response. Finally, the Rogowski coil sensor is experimentally evaluated in the measurement of a surge current pulse that emulates a real scenario.

3D printing and additive manufacturing technologies are increasingly being employed for electronics, RF, and microwave applications because they allow high design flexibility at low cost and rapid prototyping. The intrinsic heterogeneity of printed parts has become a challenge from an electromagnetic compatibility standpoint due to their unknown impact on the electromagnetic behavior of such prototypes. To estimate relevant EMC characteristics, such as the shielding effectiveness, characteristic impedance, and coupling effects it is fundamental to know the effective dielectric permittivity of such heterogeneous structures. In this paper, the dielectric permittivity of 3D printed PLA structures is measured using the stepwise Nicolson-Ross-Weir method in the 1 GHz – 6 GHz frequency range. The influence of the layer thickness and the infill percentage is investigated.

In 2015, the energy measurement of some static electricity meters was found to be sensitive to specific conducted electromagnetic disturbances with very fast current changes caused by highly nonlinear loads, leading to meter errors up to several hundred percent. This article describes new results on the electromagnetic compatibility (EMC) of 16 different meters from all over Europe when exposed to real-world disturbance signals. Those test signals were obtained from household appliances and onsite measurements at metered supply points all over Europe. The results show that also the interference signals recorded onsite can cause measurement errors as large as several hundred percent, even for meters that pass the present EMC standards. This unambiguously demonstrates that the present immunity testing standards do not cover the most disturbing conducted interference occurring in present daily-life situations due to the increased use of nonlinear electronics. Furthermore, to enable the adoption of potential new test waveforms in future standards for electricity meter testing, artificial test waveforms were constructed based on real-world waveforms using a piece-wise linear model. These artificial test waveforms were demonstrated to cause meter errors similar to those caused by the original real-life waveforms they are representing, showing that they are suitable candidates for use in improved standardization of electricity meter testing.

Static energy meters have shown errors beyond the standards due to conducted electromagnetic interference of pulsed currents. This was observed in several case studies and confirmed by laboratory experiments, which showed errors up to 2675%. The extent of this interference case is unknown, because there is limited information about the waveforms occurring in the real on-site scenarios. This article aims to detect critical waveforms in on-site surveyed data that have similar characteristics as the pulses that resulted in metering errors. The time-domain parameters of the laboratory experiments that show static energy meter interference are compared to the on-site waveform data using an interpolation based on an inverse weighting distance function. Using this approach, the waveform characteristics are compared, and an error is estimated. This approach was satisfactorily validated using data from validation experiments that shows a correct estimation of the actual error according to the permissible limits for energy metering for all validation indices. The performed on-site surveys show the existence of nonlinear waveforms. During the survey of three sites for ten days, 19 531 waveforms were captured, of which 14 487 indicate large nonlinearities and 379 are estimated to produce metering errors up to 925%.

This article presents a time-domain waveform model developed to characterize pulsed, nonlinear, current waveforms resulting in electromagnetic interference on static energy meters. The waveform model is calculated by fitting the sampled waveform data into a linear piece-wise function through a process that involves applying algorithms of pulse extraction, change-point detection, and redundancy elimination. The model is applied to data from laboratory experiments that have indicated critical current waveforms resulting in electromagnetic interference problems with static meters. Afterwards, the parameters of the modeled waveforms are calculated in order to correlate them to metering errors. The most relevant parameters that are correlated to significant errors are the maximum slope, crest factor, pulse duration, and charge. The waveform model provides an accurate description of the complex nonlinear waveforms through simplified analytical expressions that reproduce the significant features of the interfering waveforms. This waveform modeling approach could be used to standardize the artificial test signals that are representative of realistic devices and scenarios.