In this talk, we present a new time domain electromagnetic tomographic imaging algorithm using coded
multiple excitation signals to reconstruct an extended object immersed in inhomogeneous medium. Three waveform encoding
techniques are developed to enable simultaneous source excitation as a way of improving computational efficiency
in nonlinear full wave tomographic imaging. By numerical simulations, we show that iterative image reconstruction algorithm using coded multiple source excitation achieves faster convergence and better quality images than the conventional single source imaging.