This thesis focuses on application and development of time-reversal (TR) based signal processing techniques using ultrawideband electromagnetic waves in microwave sensing and imaging. This fundamental symmetry of physics, the time-reversal invariance, can be exploited in the domain of wave physics, in acoustics and more recently in electromagnetics, leading to a huge variety of experiments and instruments both for fundamental physics and engineering applications. TR techniques exploit the time reversal invariance of the wave equation to take advantage of the retransmitted (time reversed) fields for improved focusing and imaging. This is because retransmitted signals propagate backwards through the same medium and undergo similar reflection, refraction and multiple scattering that they underwent during the forward propagation, resulting in focusing around initial source locations. The refocusing resolution can overcome the justify; MARGIN: 0cm 0cm 0pt" Key Words Time reversal, Microwave imaging, Remote sensing, Time reversal operator, Radar target .
