Grant: Discovery Grants Program - Individual

Shaping electromagnetic (EM) radiation patterns, also known as beam shaping, has numerous applications in wireless communications, satellite communications, remote sensing, and imaging. A compact and cost-effective approach for beam shaping has been recently offered by EM metasurfaces. These devices, which resemble thin poster frames, transform incoming EM waves into desired outgoing ones. Thus, metasurfaces achieve beam shaping through transformation, and not by designing new antenna elements. They are, therefore, conceptually similar to electric transformers where existing voltages are transformed into desired voltages, without the need to design new voltage sources.  The overarching goal of my research program is to design compact, smart, and real-time EM systems for beam shaping and imaging. In this pursuit, metasurfaces are suitable candidates due to their thin structures, and their ability to perform reconfigurable beam shaping, spectral tailoring, and analog computations. To achieve these functionalities, advanced metasurfaces are emerging that incorporate more features and properties into their structures. However, conventional design approaches fail to provide systematic paths for advanced metasurface design due to the increasing number of design parameters and constraints, as well as the various forms of desired specifications that need to be met. Thus, the objectives in this cycle of my discovery grant are focused on (i) the development of systematic procedures to facilitate the design of advanced metasurfaces, and (ii) the seamless integration of these advanced metasurfaces into imaging systems to enhance the achievable image accuracy.   The methodology used by my group is based on the EM inversion framework, which offers a key advantage: providing a systematic procedure to infer the required metasurface properties from various forms of user-defined desired specifications. To this end, this framework casts the metasurface design problem as an EM inverse problem and then solves it by a combination of optimization algorithms, regularization schemes, and EM solvers to yield the final designs. These designs are fabricated using printed circuit board technology and then experimentally evaluated in antenna measurement systems and imaging systems. The main novelties lie in the innovative formulations of the associated inverse problems and the developed inversion techniques. This research contributes to the wireless and satellite communication industry by providing systematic design approaches that shorten the metasurface design cycle and empower these industry sectors to precisely balance desired specifications against practical constraints. Moreover, the integration of metasurfaces into imaging devices can result in innovative new products in the medical imaging sector. Given the substantial market size of these two fields, there are significant job prospects for the highly qualified personnel trained in this research program.