STAR-RIS for Integrated Communication, Computing, and Sensing

This paper presents a dual-functional Simultaneous Transmission and Reflection Reconfigurable Intelligent Surface (STAR-RIS) that integrates communication via reflection and computation/sensing via transmission within a single aperture. When an incoming wave impinges on the STAR-RIS, part of it is reflected for communication, while the transmitted portion, shaped by a lens phase profile, performs Fourier transformations in the $k$-domain enabling computational tasks. A coding metasurface approach is used to create a linear phase gradient in the reflection space and a lens phase profile in the transmission space. This enables tailored beam patterns for reflection and computational tasks, such as Fourier transforms, for accurate angle-of-arrival estimation and sensing applications. To validate the concept, a STAR-RIS with side-by-side reflection and transmission arrays is designed, fabricated, and tested at 26 GHz.