Jordi Solé-Lloveras

This paper proposes a high-frequency model for Rogowski coils implemented on printed circuit boards that extends existing transmission-line models developed for wire-wound helical coils, which assume a uniform induced-voltage distribution. The model explicitly accounts for the non-uniform spatial distribution of induced voltages along the winding and supports arbitrary bilateral terminations. This is achieved by calculating the partial mutual inductance between the primary conductor and the traces and vias of the sensor, the former modeled as transmission line segments and the latter treated as lumped voltage sources. Three relevant cases are studied: a critically damped coil, a bi-matched coil, and a self-integrating coil. Analytical expressions are obtained for each case, and a comparison with classical models shows equivalence for simplified scenarios that assume uniform mutual inductance for the first two cases under appropriate conditions. Moreover, the new model reveals bandwidth limitations for the self-integrating case and predicts the frequency response of the bi-matched termination, the latter a sensor configuration not fully covered to date. Experimental validation is conducted on representative samples of the modeled current sensor using a custom-made test fixture, yielding excellent agreement between the measured and predicted transfer impedance.

Although the time domain approach to electromagnetic interference evaluation offers numerous advantages, including shorter test duration and multi-channel acquisition, its practical adoption remains limited. This is mainly because existing standards, such as CISPR 16-1-1, do not explicitly address direct sampling time domain measuring receivers or define specific calibration and validation procedures for them. While several studies have demonstrated successful use cases, a comprehensive validation of such systems has not yet been performed. This paper presents multi-level experimental validations of time domain measuring receivers, focusing on the direct sampling approach and oscilloscope-based implementations. Firstly, meta-comparisons of FFT-based receivers are made using calibration data obtained from certificates of accredited laboratories. Then, controlled signal sources with known time and spectral characteristics are used to cross-check with different measuring receiver models. Finally, several instruments are benchmarked with respect to their standard detector outputs when measuring the emissions of a power converter while spread spectrum techniques are used. The results show good agreement between the measuring receivers in the time domain and the tested conventional receivers in the frequency domain within the standard error, even though the complexity of the measured signals is different.

This paper studies the evolution and impact of low-cost Global Navigation Satellite System (GNSS) jammers, which pose a significant threat to devices that use geolocation. Three illegally marketed jammers with distinct morphologies have been characterized in power and frequency occupancy, using time and frequency domain measurements. Also, the jammers potential effective range is approximated. The study compares both methodologies with the aim of advocating for the use of time domain measurements to provide more detailed insights into jamming influence and behavior using spectrograms and probability distribution analysis. The results show that these devices employ chirp signals or modulated wideband noise to disrupt the pseudo range acquisition by corrupting the data transmitted by satellites, masking the signals, or blocking and saturating receivers of GNSS systems utilizing signals in the Ll, El, Bl, and Gl frequency bands. The study further highlights the accessibility and effectiveness of such illegal devices, underscoring the need for jamming detection techniques.

Conducted emissions measurements are a must in the aerospace industry to ensure the intended electromagnetic performance of on-board systems. Line Impedance Stabilization Networks are a key element for such tests since they provide a stable and reliable reference impedance. However, the LISN response can degrade over time due to typical wear, environ-mental factors, vibrations, or aging, potentially compromising the measurement accuracy. Regular calibration is, therefore, critical to maintain measurement integrity. Traditional LISN calibrations involve costly and complex equipment, such as vector network analyzers and impedance meters. This paper proposes an alternative and cost-effective method for LISN calibration using general-purpose oscilloscopes and arbitrary waveform generators to determine the voltage division factor and input impedance. The approach is validated by calibrating a custom LISN built according to ECSS standards. This method reduces costs, simplifies the calibration process, and allows users to perform, in-house, internal verifications.