Electromagnetic signals in the frequency range of 30–300 GHz can penetrate through materials like clothing, fog, and smoke, and at the same time provide image reconstruction with fine spatial resolution. Millimeter-wave imaging is typically implemented by means of mechanical or electrical scanning which requires long data acquisition times or a large number of active components. Passive millimeter-wave imaging systems that capture thermal signals and operate similarly to optical cameras are very costly because they need to employ highly sensitive receivers due to thermal radiation being extremely low power at millimeter-wave frequencies. This talk presents a newly developed millimeter-wave imaging technique called active incoherent millimeter-wave (AIM) imaging which combines the benefits of active and passive millimeter-wave imaging. This approach combines the high signal-to-noise ratio capabilities of active millimeter-wave imaging systems with the fast image formation potential of passive millimeter-wave imaging systems. The combination is achieved by illuminating the scene with multiple spatially distributed noise transmitters that mimic the randomness of thermal radiation. Starting from our earlier work in microwave frequencies, I discuss the system design and calibration approach, along with an experimental demonstration of a millimeter-wave active incoherent digital array. The array can generate millimeter-wave video at very high frame rates, and millimeter-wave imaging results include video captured at 652 frames per second of a sphere in pendulum motion. The use of stray reflections from a small set of communication transmitters is also examined, and incoherent imaging results using WiFi and 5G signals are presented.
Speaker(s): Dr. Stavros Vakalis
800 W Campbell Rd, Richardson, Texas, United States, 75080