Dielectric property imaging system in the millimeter wave range

We developed a system for imaging the dielectric properties of various materials in the millimeter range from 25 GHz to 65 GHz. It can observe the distribution of dielectric properties, i.e. complex permittivity, of materials including composites. The system uses two silicon hemispherical lenses and two off-axis parabolic mirrors, and the signal is observed by a network analyzer. Experimental results proved that the system clearly observes metal or water distributions in other dielectric materials at 35 GHz and at 60 GHz, by reflection imaging as well as by transmission imaging. One of the important features in practice is its ability to distinguish water and ice. The new imaging system can used to evaluate the distribution of dielectric properties of various materials in the Ka and V bands.