Programmable radio-frequency calculations in electromagnetic-wave domain

Information metasurfaces have emerged as pivotal components in next-generation electronic systems. However, current research is mainly focused on the physical structures and system functions, while radio-frequency signal processing and calculation remain constrained to digital-domain operations. The reliance on digital conversion inherently increases the hardware complexity and power consumption. To address this challenge, we propose a programmable radio-frequency calculation system based on a space-time-coding metasurface, which controls the wave-matter interactions to achieve radio-frequency calculations in the electromagnetic space in a reprogrammable way. Particularly, the fundamental signal operations - Fourier transform and convolution - are implemented in the electromagnetic-wave domain successfully. We validate the calculation capabilities in radar scenarios, facilitating the accurate detection of target velocity and range. In this work, theoretical analysis, numerical simulations, and experimental results collectively demonstrate that the radio-frequency calculation system exhibits superior precision and notable cost-effectiveness, highlighting its significant potential for next-generation electronic system deployments. The authors demonstrate a programmable metasurface that directly performs Fourier transforms and convolutions on radio-frequency waves, enabling reconfigurable real time signal processing while reducing reliance on conventional digital hardware.