Time Reversal for Electromagnetism: Applications in Electromagnetic Compatibility

Recently, modern power electronic systems have been introduced in different applications, such as in avionics and wireless communication. The increasing technological complexity of these systems is posing serious challenges regarding electromagnetic compatibility (EMC) issues. Indeed, the radiation emitted from electronic circuits can induce harmful effects on nearby devices. Thus, several research works have been conducted using the nearfield technique to deal with electromagnetic interferences (EMI) that might occur, especially due to rapidly changing currents and voltages. In the present work, a detailed study about the characterization of the electromagnetic nearfield-radiated emissions is established using a time-domain analysis to provide an equivalent model constituted of a set of electromagnetic dipole parameters. Source reconstruction has been obtained using electromagnetic time reversal (EMTR), which has proven successful and efficient in identifying transient disturbance sources in power electronics. Experimental measurements of the magnetic nearfield have been carried out under an AC/DC flyback converter. The accuracy of the proposed method has been confirmed by visualizing measured magnetic field components, which are in good agreement with the calculated maps. The results of a reasonable computing time have shown that, particularly in transient signals with a wide frequency band, the suggested inverse method is an adequate alternative to overcome frequency domain limitations.

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Single-Sensor EMI Source Localization Using Time Reversal: An Experimental Validation

Electronics ◽

10.3390/electronics10192448 ◽

2021 ◽

Vol 10 (19) ◽

pp. 2448

Author(s):

Hamidreza Karami ◽

Mohammad Azadifar ◽

Zhaoyang Wang ◽

Marcos Rubinstein ◽

Farhad Rachidi

Keyword(s):

Source Localization ◽

Time Reversal ◽

Electromagnetic Interference ◽

Electromagnetic Compatibility ◽

Experimental Validation ◽

Three Dimensional ◽

Monopole Antenna ◽

Reversal Process ◽

Receiving Antenna ◽

Backward Propagation

The localization of electromagnetic interference (EMI) sources is of high importance in electromagnetic compatibility applications. Recently, a novel localization technique based on the time-reversal cavity (TRC) concept was proposed using only one sensor, and its application to localize EMI sources was validated numerically. In this paper, we present a validation of the proposed time-reversal process in which the forward step of the time-reversal process is performed experimentally and the backward step is carried out via numerical simulations, a realistic scenario which is applicable to practical source localization problems. To the best of the authors’ knowledge, this is the first implementation of a three-dimensional electromagnetic time-reversal process in which the forward signal is provided experimentally while the backward propagation step is carried out numerically. The considered experimental setup is formed by a partially open cavity and two monopole antennas to emulate the EMI source and the sensor (receiving antenna), respectively. Assuming that the location of the source is the feed point of the monopole antenna, the resulting three-dimensional location error in the experimental validation was only 1.49 cm, which is about one-third the length of the monopole antenna, corresponding to about λmin/2 (diffraction limit).

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