EE Devices Seminar- Yasaman Ghasempour, Princeton U

The mmWave and sub-THz spectrum is rapidly emerging as a foundation for next-generation wireless communication and sensing systems, driven by its immense available bandwidth and sub-millimeter wavelengths. Yet, practical deployments face fundamental challenges: severe propagation loss, susceptibility to blockage, power-demanding PHY, and the breakdown of traditional far-field assumptions. Unlocking the full potential of these frontier frequencies demands physics-native solutions that capitalize on the unique properties of signals in these regimes. In this talk, I will first present an ultra-wideband retro-directive backscatter architecture above 100 GHz that departs from conventional large-scale antenna arrays and significantly reduces the power consumption. I will then discuss how the migration to higher frequencies, together with electronically large arrays, has extended the Fraunhofer limit from a few centimeters to several meters—placing many users into the electromagnetic near-field of future base stations and access points. Despite decades of progress in wireless communications, this near-field regime remains largely unexplored. I will show how programmable near-field beam shaping unlocks exciting new opportunities for communication and sensing. In particular, I will present AI-assisted self-curving beams that bend around obstacles in the environment, offering a path toward the long-standing vision of seamless connectivity in the presence of dynamic blockages. Finally, I will conclude by highlighting unprecedented application domains of mmWave/sub-THz sensing and imaging across disciplines such as agriculture and robotics, underscoring the transformative potential of these frontier bands.