An automated technique for the active imaging of dielectric layered media

A computer based automated technique for the active imaging of dielectric layered media is presented. The method is based on illuminating the unknown dielectric media by an electromagnetic wave of known characteristic and reconstructing the dielectric properties of the media from the reflection coefficient data measured at the air-dielectric interface. The dielectric samples of the material under test (MUT) are machined and fitted precisely into a section of a coaxial airline to measure the reflection coefficient data over a wide frequency band. A computer is directly connected to the vector network analyzer and a geometrical method along with our previously proposed renormalization technique is used to implement the automation of the permittivity profile determination. The different layers of the dielectric media are reconstructed quite accurately from the measured reflection coefficient data in all cases.