Abstract: In a microwave imaging system, a three dimensional profile of the dielectric permittivity of a target is obtained. A transmitter transmits microwaves toward a target, and the target scatters the microwaves. The scattered waves are received by an antenna and are converted into suitable data for application to a digital computer. The computer processes the data using either a scattering matrix algorithm or a Fourier transform algorithm. The computer then generates data representative of a three dimensional profile of dielectric permittivity which can be displayed on a suitable display device such as a CRT.