Dr Rahimian Omam

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.

This paper highlights the crucial importance of polarization control within 5G wireless communication. We propose a compact polarization converter on a thin ferrite-based metasurface, which enables flexible manipulation of polarization in the reflected waves. The direction of applied magnetics bias allows the metasurface to polarize reflected waves in either co-or cross-polarization with respect to the incident wave. To optimize ferrite utilization, the adoption of a cubic lattice structure in metasurface design is recommended. This design approach has successfully delivered efficient polarization conversion and showcased impressive frequency reconfigurability. Each unit cell within the proposed metasurface can be independently controlled for spatial modulation. Utilizing the distinct material properties associated with various polarizations, the suggested metasurface exhibits remarkable potential in creating reflective intelligent surfaces. These surfaces have the capacity to substantially enhance coverage and elevate the performance of 5G networks. Index Terms—Ferrite, metasurface, polarization control, 5G, non-reciprocal wave propagation, Faraday rotation. I. INTRODUCTION As the demand for high-speed, low-latency, and reliable wireless communication continues to surge, the development of advanced technologies to enhance 5G networks becomes dominant. Metasurfaces in 5G applications enable precise beamforming and enhance wireless communication efficiency, revolutionizing the way data is transmitted and received, thus shaping the future of high-speed connectivity [1]–[3]. In this context, the manipulation of electromagnetic wave polarization has emerged as a crucial factor for improving the performance and efficiency of communication systems. Polarization converters, which can transform incident waves into desired polarizations, have garnered significant attention [4], [5]. This paper considers solutions in the form of a compact polarization converter, engineered on a thin ferrite-based metasurface, that holds great potential for revolutionizing 5G wireless communication. In previous investigations, various geometries have been investigated for achieving linear-to-cross polarization conversion , such as H-shaped metallic structures [6], the double-split ring resonator [7], and double V-shaped resonators [8]. Additionally, the effective realization of linear-to-circular polarization conversion has been demonstrated through designs like the Jerusalem Cross resonator and corner-truncated patch resonator [9]. Notably, a reconfigurable metasurface,