Design challenges for millimeter wave active imaging systems

Due to the atmospheric absorption in W-band, especially the spectrum around 94 GHz has been the frequency of choice for radar applications in reconnaissance and metrology, but more recently also for indoor security applications. However, for indoor security applications the propagation environment and scale of the application is quite different as compared to the long-range military and scientific applications. In this paper we report on the work performed at the research group ESAT-TELEMIC on modelling and designing indoor millimeter wave imaging systems that employ coherent multi-parametric illumination in a “flash”-like configuration. We discuss trade-offs between certain system parameters and present two examples of multi-parameter imaging. We show that a 2.5D simulator is a good compromise between computational cost and ability to analyse interference effects such as speckle. We also elaborate on challenges in terms of hardware implementation, and demonstrate experimentally the potential of using printed antennas for millimeter wave security applications.