ECE PhD student Zhanni Wu has been awarded a Rackham Predoctoral Fellowship to support her research in novel metasufaces, which could lead to breakthroughs in areas such as next-generation wireless communication, commercial and military radar systems, imaging, and antenna systems.
Wu works with Prof. Anthony Grbic on a $7.5M Multidisciplinary University Research Initiative (MURI) to develop magnet-free, non-reciprocal metamaterials that can break the time reversal symmetry of conventional electromagnetic systems. Metamaterials are subwavelength-structured, man-made materials that manipulate electromagnetic waves or sound in ways that don’t occur in nature. Metasurfaces are two dimensional implementations of metamaterials.
Most metasurface functions are fixed. Wu focuses on developing tunable and spatiotemporally modulated metasurfaces to enable multiple functions. By integrating components with tunable electrical properties into metasurfaces, it’s possible to manipulate electromagnetic waves in real-time and realize optical phenomena, such as frequency conversion and nonlinear and nonreciprocal behaviors.
Wu has designed a time-modulated metasurface that exhibits Doppler-like frequency conversion. If you were to use Doppler radar (which is what the police use to catch you speeding) on the metasurface, the surface would shift the frequency so the radar would read a speed different from the actual velocity.
Wu is also designing a spatiotemporally modulated metasurface that shows nonrecoprocity. This surface will affect the transmission and reception of electromagnetic waves. The resulting time-modulated, nonreciprocal metasurfaces are expected to outperform magnet-based approaches while also being cost-effective, compact, and compatible with electronic integration.
“Spatial-temporal modulation is very new, and we’re one of the first groups to actually fabricate this kind of metasurface, so it’s very exciting,” Wu says. “It’s a very competitive, active area of research, and I enjoy being a part of it.”
Wu earned her Bachelor of Engineering in Electronic and Communication Engineering from Southeast University, Nanjing, China. She is a member of the Radiation Laboratory.
About the Rackham Predoctoral Fellowship
The Rackham Predoctoral Fellowship supports outstanding doctoral candidates who are actively working on dissertations that are unusually creative, ambitious and impactful.