Experimental results in an anechoic chamber of temporal waveforms (first row), frequency spectrum (second row), and focal spots obtained by TR (third row), for the 3 antennas placed in the far field of the structure at relative angles 0°, 45°, and 90°. In each case, the signals are very elongated due to the resonant nature of the medium only, the spectrum displays increasing quality factors for frequencies approaching , and the focal spots are wide. The last row presents a focal spot obtained using TR with the 3 antennas at a time. The focal spot is again wide and the sidelobes are lowered.