BEL KAMEL Emna, PEDEN Alain, PAJUSCO Patrice

**RCS modeling and measurements for automotive radar applications in the W band**. EUCAP 2017 : 11th European conference on antennas and propagation, 19-24 march 2017, Paris, France, 2017, pp. 2445-2449*This paper describes a reliable methodology for radar cross section (RCS) measurement of complex small and large targets in the W band. The backscattering behavior of a small car model was measured in an anechoic chamber along with various automotive related targets in a wide gymnasium. Experimental performance in the anechoic chamber is compared to the simulation results. Our simulation model is based on deterministic scattering centers, determined by high frequency approaches, like the physical optics (PO) and the physical theory of diffraction (PTD). Nevertheless, simulations of realistic large objects are both time consuming and difficult to implement. The proposed measurement configuration enables the extraction of non-predetermined scattering points for large object modeling which will significantly decrease the simulation time for road scenarios in radar applications. *

JAIN Ankit, PAGANI Pascal, FLEURY Rolland, NEY Michel, PAJUSCO Patrice

**Efficient time domain HF geolocation using multiple distributed receivers**. EUCAP 2017 : 11th European conference on antennas and propagation, 19-24 march 2017, Paris, France, 2017, pp. 1852-1856*This paper explores the effect of increasing number of receivers to evaluate the geographic location of the High Frequency (HF) transmitters for distances in the radius of 2000 km. In the case of HF propagation over long distances, signals propagate using skywaves and are reflected back to the earth from the ionosphere. The Quasi-Parabolic (QP) model of the ionosphere provides analytic equations for ray path parameters through which the signal travel time is obtained. The position of the transmitter is found using time domain HF geolocation method namely Time Difference of Arrival (TDoA). An analysis of the QP model of the ionosphere is provided and limits of the model are emphasized. The geolocation algorithm for TDoA along with its mathematical equation is explained. Simulation results demonstrate that increasing the number of receivers leads to a significant improvement in the geolocation accuracy. *

PILLAIN Axelle

**Line, Surface, and Volume Integral Equations for the Electromagnetic Modelling of the Electroencephalography Forward Problem**. Th. doct. : Sciences de l'Ingénieur, Institut Mines-Télécom-Télécom Bretagne-UEB, UMR CNRS 6285 - Télécom Bretagne - Université de Bretagne Occidentale - Université de Bretagne Sud - ENSTA Bretagne - Ecole Nationale d'ingénieurs de Brest, october 2016*Electroencephalography (EEG) is a very useful tool for characterizing epileptic sources. Brain source imaging with EEG necessitates to solve the so-called EEG inverse problem. Its solution depends on the solution of the EEG forward problem that provides from known current sources the potential measured at the electrodes positions. For realistic head shapes, this problem can be solved with different numerical techniques. In particular surface integral equations necessitates to discretize only the interfaces between the brain compartments. However, the existing formulations do not take into account the anisotropy of the media. The work presented in this thesis introduces two new integral formulations to tackle this weakness. An indirect formulation that can handle brain anisotropies is proposed. It is discretized with basis functions conform to the mapping properties of the involved operators. The effect of this mixed discretization on brain source reconstruction is also studied. The second formulation focuses on the white matter fiber anisotropy. Obtaining the solution to the obtained numerical system rapidly is also highly desirable. The work is hence complemented with a proof of the preconditioning effect of Calderon strategies for multilayered media. The proposed theorem is applied in the context of solving the EEG forward problem. A Calderon preconditioner is also introduced for the wire electric field integral equation. Finally, preliminary results on the impact of a fast direct solver in solving the EEG forward problem are presented. *

PAGANI Pascal, SCHWAGER Andreas

**A Statistical Model of the In-Home MIMO PLC Channel based on European Field Measurements**. IEEE journal on selected areas in communications, july 2016, vol. 34, n° 7, pp. 2033-2044*The Multiple-Input Multiple-Output (MIMO) technique is well known in the field of wireless communications, and has recently been proposed to increase the capacity of in-home Power Line Communication (PLC) networks. MIMO PLC employs the Protective Earth in addition to the classical Line and Neutral wires, to form a multi-sensor transmission channel. By considering the additional reception of Common Mode signals, up to 2 simultaneous transmit ports and 4 receive ports can be considered. In order to develop new signal processing strategies optimally exploiting the MIMO propagation characteristics, and to evaluate their performance, accurate modeling of the transmission channel is necessary. This paper presents a comprehensive statistical model of the in-home MIMO PLC channel based on an extensive measurement data base collected in 6 European countries. The study first analyses the main MIMO PLC channel parameters, including path loss parameters and wideband parameters such as the delay spread, coherence bandwidth and small-scale statistics. A focus is then made on the MIMO correlation matrix, and its modelling using empirical statistical distributions. A fully parameterized channel model is then developed, with a particular emphasis on both the frequency fading structure of the transfer function and the correlation matrix between sub-channels. As a result, the proposed model generates random MIMO PLC channel realizations statistically representative of the experimental observations. *