Complex natural resonances extracted from radar signatures measured in time domain with UWB laboratory system

The Centre d\´Electronique de l\´Armement (CELAR) has studied and developed ultra wide band (UWB) time domain "laboratory" instrumentation. UWB radars emit an instantaneous short pulse including a large frequency spectrum. Two potential applications of these systems, allowed by using mainly the lower frequencies, are the detection and the identification of stealth targets and buried objects (like unexploded ordnances and mines). Good penetration into a lossy ground needs frequencies lower than 300 MHz; it becomes a major difficulty for the efficient use of radar imaging techniques, because of the poor resulting resolution. This is the reason why other identification and classification techniques, like these based on the singularity expansion method have been extensively analysed and develop over the years.