Time-domain processing of electromagnetic data for multiple-target detection

Time Reversal Experiments in the Microwave Range: Description of the Radar and Results

“…(6). Employing the same technique, good results have also been found in [15], although the physical justification had not been given. In cases where the waves propagate in more complex conditions, such as in a waveguide [25], the Green function loses its "linear-phaseover-frequency" property and the proposed solution fails.…”

“…1) electric field [29]. Antennas based on the same design have also been employed in [9,15]. The distance between the antennas of the array is set to 5 cm (λ 0 /2 at 3 GHz) to avoid grating lobes while limiting antenna coupling.…”

“…The signal received by the selected antenna is indeed the result of both diffracted field coming from the object (useful signal) and direct field coming from the neighbor transmitting antenna (noise). To reduce this unwanted contribution, we actually perform differential measurements [15]. Once the total field matrix K t is acquired, the incident field matrix K i is Figure 7.…”

“…The RF front-end is made of a linear array of 8 UWB antennas plus one more spare antenna working in a multistatic configuration. Antennas are antipodal symmetric Exponentially Tapered Slot Antennas (ETSA), printed on a Duroid substrate of permittivity r = 2.2 and dimensions 8 cm × 8 cm; they show very good input impedance matching (SWR < 2) in the [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] GHz frequency band and radiate a vertically-polarized (perpendicular to the plane of Fig. 1) electric field [29].…”

“…Nonetheless, thanks to a precise mechanical support, they can be placed at different positions in order to artificially "build" two arrays. Finally, Cresp et al [15] use a bandwidth of 6.5 GHz with a linear eight-antenna array.…”