Farhad Rachidi-Haeri

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Impulse radiating antennas, proposed by C. E. Baum in 1989 [1], allow to generate impulse-like, broadband, high-amplitude electromagnetic fields. Applications include electromagnetic compatibility testing and remote sensing [2,3]. Analytical and semi-analy ...

In this paper, we present a review and classification of the published works on the use of Electromagnetic Time Reversal (EMTR)-based methods to locate landmines. Different approaches for landmine localization using EMTR are investigated. Specifically, the ...

Recently, a closed time-reversal cavity for electromagnetic waves was demonstrated and experimentally realized using a network of transmission lines. This paper presents an analysis in the frequency domain of the wave propagation characteristics that perta ...

Presents an analysis in the time and frequency domains of the electromagnetic field originated by negative lightning return strokes, calculated at ground level. The analysis is performed on the basis of the transmission line model modified by the authors, which gives results in good agreement with experimental data. The influence of several parameters which deeply affect the time waveshape and the frequency spectra of the electromagnetic field has been investigated. These parameters are: the rise time and t

Understanding how the path of streamers is influenced by background electric fields is crucial in leader progression models and electrical breakdown models in long gaps. While numerous advanced models of streamers exist, applying them to leader progression models to track streamer movement remains computationally intensive and impractical. In this study, we employ one of the simplest streamer models available in the literature to investigate how streamers are deflected in the presence of background electric

The paper addresses the research question of whether the electromagnetic time reversal (EMTR) technique can be used to estimate the propagation speed of a signal on power cables. This value changes in the long term due to ageing of the cable insulation and ...

We discuss in this paper the influence of the height of an elevated strike object on the magnitude of lightning radiated electric and magnetic fields. For the analysis, the transmission line (TL) return stroke model for the lightning channel is adopted and the strike object is represented by a uniform lossless transmission line. Analytical expressions derived recently by the authors for the radiated electric and magnetic fields are used to investigate the influence of the height of the elevated strike objec

In this paper, a time-domain variant of the generalized telegrapher's equations for transient electromagnetic field coupling to a finite-length wire above a lossy half-space is derived. The approach is fully based on the thin-wire antenna theory. The lossy ...

Experimental data characterizing indoor electric and magnetic fields radiated by power line communication (PLC) systems and used for the calculation of a local transfer function (coupling factor) are presented. It is shown that the indirect determination of electric field using magnetic field measurements and assuming a plane wave approximation may result in an underestimation of the electric field. Additionally, it is shown that the radiated field magnitudes vary significantly as a function of the position

We use a full-wave finite-element-based solution of Maxwell's equations for the evaluation of lightning electromagnetic fields inside a vertically stratified, two-layer ground (ocean-land mixed propagation path) and their induced currents on the shield of ...

The paper presents the characteristics of a system suitably developed to measure lightning current waveforms on the Santis Tower in Switzerland. The paper first describes the configuration of the system then presents the characteristics of the measurement ...

The evaluation and the analysis of the lightning electromagnetic pulse (LEMP) response of distribution networks require the availability of accurate models of LEMP-illuminated lines and their implementation into software tools able to calculate lightning-induced electromagnetic transients in distribution systems having complex configuration. This paper deals indeed with a computer code, LIOV (lightning induced overvoltage code), and with two interfaces recently realized between it and (a) the DCG/EPRI EMTP9

In this paper, we derive an integral equation describing the antenna-mode currents along a two-wire transmission line (TL). We show that when the cross-sectional dimensions of the line are electrically small, the integral equation reduces to a pair of TL-l ...

The paper presents an automated FPGA-based real-time electromagnetic transients simulator for power electronics and power systems applications. The simulator features an automated procedure enabling its straightforward applications to different topologies ...

We present and discuss current waveforms associated with 13 bipolar lightning flashes recorded at the Santis Tower during the period from June 2010 to January 2015. During this period, a total of 427 flashes were recorded, of which 13 (3%) were classified ...

This paper presents an adaptive dynamic Q-factor continuous wavelet transform (ADQ-CWT) algorithm for accurate natural frequency identification in power system fault transient analysis. The proposed approach dynamically adjusts the Q-factor of the analysing wavelet by modifying its centre frequency and time-decay parameter, thereby optimising the trade-off between time and frequency resolution across multiple scales. To further enhance temporal localisation and suppress redundant low-frequency components, m

An unusual negative lightning flash was recorded at the Säntis Tower on June 15, 2012. The flash did not contain an initial continuous current typical of upward negative lightning, which is the most common type of event at the Säntis Tower. The flash conta ...

Recently, engineering return stroke models were extended to take into account the presence of an elevated strike object, which was modeled as an ideal uniform transmission line. We show in this paper that the current distribution associated with these extended models exhibits a discontinuity at the return stroke wave front, which cannot be considered to be physically plausible. This discontinuity arises from the fact that the current injected into the tower from its top is reflected back and forth at its en

This paper presents an FPGA-based (field programmable gate array) real-time digital simulator for power systems and power electronics applications. The proposed approach integrates the Modified Nodal Analysis (MNA) method, the Fixed Admittance Matrix Nodal ...

The peak current estimation of lightning detection networks for strikes to tall towers is discussed in this paper. Such systems are sometimes calibrated using return-stroke current data obtained by means of rocket-triggered lightning or instrumented towers ...

Farhad Rachidi-Haeri

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Semi-analytical gray-box modeling of antennas in the time domain and application to impulse radiating antennas

Landmine Detection Using Electromagnetic Time Reversal-Based Methods: 1. Classical TR, Iterative TR, DORT and TR-MUSIC

A Frequency-Domain Analysis of a Time-Reversal Cavity for Electromagnetic Waves in Transmission Line Networks

Analysis of electromagnetic field originated by lightning return stroke in the time and frequency domain

Deflection of Electric Streamer Channels in an Applied Electric Field

Exploring Electromagnetic Time-Reversal as a Method to Monitor Cable Temperature in Medium-Voltage Networks

Influence of the height of an elevated strike object on the enhancement of lightning radiated fields

Time-Domain Generalized Telegrapher's Equations for the Electromagnetic Field Coupling to Finite Length Wires Above a Lossy Ground

Indoor radiated emission associated with power line communication systems

Lightning Electromagnetic Fields and Their Induced Currents on Buried Cables. Part I: The Effect of an Ocean-Land Mixed Propagation Path

A system for the measurements of lightning currents at the Säntis Tower

Lightning-induced voltages on complex distribution systems: models, advanced software tools and experimental validation

On the evaluation of antenna-mode currents along transmission lines

An automated FPGA real-time simulator for power electronics and power systems electromagnetic transient applications

Bipolar Lightning Flashes Observed at the Säntis Tower: Do We Need to Modify the Traditional Classification?

Adaptive dynamic Q-factor continuous wavelet transform for natural frequency extraction in fault-originated transient signals

A Study of a Large Bipolar Lightning Event Observed at the Säntis Tower

Electromagnetic field radiated by lightning to tall towers: treatment of the discontinuity at the return stroke wave front

A general purpose FPGA-based real-time simulator for power systems applications

On the Current Peak Estimates Provided by Lightning Detection Networks for Lightning Return Strokes to Tall Towers