Roman Jobava - Academia.edu (original) (raw)

Papers by Roman Jobava

2017 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI), 2017

In this paper, we demonstrate a methodology for fast virtual testing of LED lighting system under... more In this paper, we demonstrate a methodology for fast virtual testing of LED lighting system under ALSE test setup. We use simulation software for generation of setup models according to ISO 11452-2 standard [1] and prediction of currents induced in LEDs. The levels of the currents are analyzed to check the possible malfunction of the system.

2017 International Symposium on Electromagnetic Compatibility - EMC EUROPE, 2017

This paper presents the hybridization of the multi-conductor transmission line (MTL) approach and... more This paper presents the hybridization of the multi-conductor transmission line (MTL) approach and method of moments (MoM) for solving automotive low-frequency (LF) EMC radiation and susceptibility problems. The hybrid solution is performed in two steps. When radiation problems are considered, the MTL solution is performed as a first step and then radiation from the MTL system is used as an excitation for a 3D LF-MoM model; for susceptibility problems, fields radiated from the 3D system are calculated using LF-MoM approach and then these fields are used as incident fields for the MTL solution. Our proposed LF MoM solution is unique in its formulation of loop-star approach for solenoidal and non-solenoidal equivalent currents applied to special boundary conditions for thin 3D sheets, characterized by both electric and magnetic material parameters. For modeling of multiconductor cable systems, efficient circuit model is implemented. The model considers shielding, losses, proximity, and...

This paper presents simulations of capacitive seat sensor performance. Quasi-electrostatic approa... more This paper presents simulations of capacitive seat sensor performance. Quasi-electrostatic approach, based on Method of Moments is used. Method is enhanced in order to take into account lossy dielectrics. Fast iterative solution is developed, which utilizes Adaptive Cross Approximation approach for matrix compression. Method is validated against analytic solutions. Simulations of seat sensor impedance in the car model for different conditions of the seat foam and three cases of occupancy of the seat (empty seat; adult on the seat; infant on the seat) are performed.

2007 XIIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory, 2007

ABSTRACT Paper presents modeling and numerical investigations of log-periodic and horn antennas p... more ABSTRACT Paper presents modeling and numerical investigations of log-periodic and horn antennas performed by method of moments (MoM). Obtained results are compared with experimental data. Comparison shows that the simulations have close agreement with measurement.

2014 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2014

This paper proposes a high-frequency dynamic circuit network model of a DC motor for predicting c... more This paper proposes a high-frequency dynamic circuit network model of a DC motor for predicting conductive emissions in low-voltage automotive applications, and discusses a study in which this model was examined. The proposed model, which is based on a behavioral approach, introduces some physical features and phenomena of motor armature windings. Together with impedance characterization current model gives possibility to perform accurate transient analysis and describe complex commutation processes in motor during rotation.

2018 International Symposium on Electromagnetic Compatibility (EMC EUROPE), 2018

This paper presents a hybrid approach to the frequency and time domain simulation of complex cabl... more This paper presents a hybrid approach to the frequency and time domain simulation of complex cable systems with arbitrary linear or linearized circuits at terminations. Depending on the type of cables to be investigated, either FDTD/MNA or MTL/MNA approach can be recommended. In FDTD/MNA scheme 1D-FDTD method is applied to solve the transient response of a cable system, which is then used together with circuits of termination devices to simulate the complete network by modified nodal analysis (MNA). In the second scheme, MTL theory is used to extract equivalent circuit models of cables. All extracted equivalent circuits are then merged with termination devices and solved using specialized MNA-based circuit solver. Both methods are speed-oriented, provide accurate results and can be used for fast simulation of large-scale cable systems. Validation of the proposed methods is performed by comparison with measurements of high voltage shielded cable test setup. Two application examples demonstrate the potential of the proposed approaches for simulation of large-scale cable systems - automotive harness and office wiring network.

2010 XVth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED), 2010

Effective computational techniques for Multi-Transmission Line (MTL) based on Lumped Circuit Tran... more Effective computational techniques for Multi-Transmission Line (MTL) based on Lumped Circuit Transmission Line (LCTL) method are suggested and applied for EMC analysis of complex cable harness. Accuracy of developed algorithms is validated by comparisons with measurements.

2017 XXIInd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED), 2017

Aim of the paper is to perform comparative study of human exposure due to low-frequency (1 Hz to ... more Aim of the paper is to perform comparative study of human exposure due to low-frequency (1 Hz to 10 MHz) electromagnetic fields for different human body models. Simulation approach based on Volume Integral Equations (VIE) combined with Adaptive Cross Approximation (ACA) technique to improve performance of numerical solution is described. Human exposure due to low-frequency uniform magnetic field is compared for several available human body voxel models.

2016 International Symposium on Electromagnetic Compatibility - EMC EUROPE, 2016

This paper presents a simulation methodology for investigation of human exposure to low-frequency... more This paper presents a simulation methodology for investigation of human exposure to low-frequency (1 Hz to 30 MHz) electromagnetic fields generated by automotive wireless power transfer (WPT) systems. The main stages of the modeling process are discussed. A new simulation approach based on the combination of computationally efficient surface integral equation (SIE) and volume integral equation (VIE) methods is proposed. In the first stage the interaction of low-frequency fields with a thin, finite, conducting three-dimensional (3D) metallic chassis of a vehicle using SIE is considered. In the second stage, a human body model is exposed to the fields inside the passenger compartment of the vehicle. The solution of the latter problem is performed by means of VIE. The accuracy and efficiency of numerical methods based on SIE and VIE are discussed. The developed approach was applied to the investigation of human exposure to fields due to WPT systems for car battery charging.

Proceedings of the 9th International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory, 2004. DIPED 2004., 2004

ABSTRACT

2014 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2014

In this article, new lumped-parameter models of current clamps are proposed and discussed. The mo... more In this article, new lumped-parameter models of current clamps are proposed and discussed. The models were extracted from measured S parameters of a clamp mounted onto a calibration fixture. The generated bulk current injection (BCI) and current probe simulation models were used in the electromagnetic (EMC) testing of a realistic cable harness according to the ISO 11452-4 standard. The accuracy and efficiency of the proposed simulation model were estimated by comparing the simulated results with measured data.

2019 49th European Microwave Conference (EuMC)

This paper generalizes a waveguide port excitation problem on arbitrary composite geometries. An ... more This paper generalizes a waveguide port excitation problem on arbitrary composite geometries. An entire problem is formulated in terms of multiple equivalent subproblems for the equivalent currents in each specific region, which are found using the Method of Moments (MoM). The obtained solution takes into account the problem of material junctions between several material surfaces. The developed approach is verified on a number of specific problems for coaxial ports connected to the printed microwave antenna and printed circuit board (PCB) geometries. A good agreement between the simulated and measured results is demonstrated.

2020 IEEE XXVth International Seminar/Workshop Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED)

This paper is devoted to the experimental validation of the modeling approach for studying the sh... more This paper is devoted to the experimental validation of the modeling approach for studying the shielding cables and their properties for high speed systems. The simulation model is based on the multi-transmission line approach, and the novelty is in special validation of shield structure parameters using measurements of transfer impedance values according to IEC 62153-4-3 [1]. The methodology presented in this paper consists of two steps. Firstly we adjust the shielded structure parameters using measured data and secondly, we assemble radiated emission setup according to CISPR 25 [2] and compare the fields produced by shielded cables with measured data.

12th European Conference on Antennas and Propagation (EuCAP 2018), 2018

2016 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2016

ESD events can damage or upset electronic vehicle systems, so discharges to the electronic system... more ESD events can damage or upset electronic vehicle systems, so discharges to the electronic systems or to the attached cables need to be considered. Discharges to the cables or to coupling structures close to the cables were investigated and a Method of Moments (MoM)-based methodology for ESD simulation is proposed. The simulation results for test benches according to ISO standards were verified against measurements.

Electromagnetic Compatibility (EMC) problems arising in electronic systems of vehicles is investi... more Electromagnetic Compatibility (EMC) problems arising in electronic systems of vehicles is investigated. In such systems the most severe interaction between electronic units is observed due to radiation or coupling through cable harness, interconnecting these units. Investigation of arising complex problems can be performed using system approach, i.e. system level combination of different approaches and tools, the most appropriate to investigation of the particular phenomenon. Developed CAE system supporting this approach is described.

DIPED - 2001. Proceedings of 6th International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (IEEE Cat. No.01TH8554), 2001

A new fast algorithm of calculation of per-unit length capacitance and inductance matrices is dev... more A new fast algorithm of calculation of per-unit length capacitance and inductance matrices is developed based on the Method of Auxiliary Sources (MAS). Method is checked against analytical solutions and available literature data. High efficiency and accuracy of the method is observed. Method is applied to cross-talk problems when transmission line approach is used as a simulation tool.

2008 IEEE International Symposium on Electromagnetic Compatibility, 2008