Active and passive THz systems for short-range imaging applications

In this paper three different systems at 94 GHz for short-range imaging applications are presented; both active and passive methodologies are described. An analysis for each case is performed, determining the parameters which satisfy the field of view and resolution requirements. A T-shape interferometric radiometer is first exposed describing the implemented imaging algorithm, the overall system block diagram, and the images obtained from the simulations. The radiometric resolution estimate is calculated, specifying the minimum temperature the system is capable to detect in function of the system parameters. Then, a Mills-Cross based active system is presented; recovered images are shown, as well as the geometry employed in the setup performance. Finally, a reflectarray setup is described; presenting its geometry of exploration and operation principles. In addition a phase discretization analysis is performed for the case of 1 bit. For both active systems the minimum detectable Radar Cross Section, RCS, is computed.