Programmable radio-frequency calculations in electromagnetic-wave domain

TL;DR

This paper introduces a reprogrammable metasurface system that performs direct RF calculations in the electromagnetic domain, reducing digital processing needs and improving efficiency for radar and communication applications.

Contribution

It presents a novel space-time-coding metasurface capable of executing fundamental RF operations like Fourier transform and convolution directly in the EM wave domain.

Findings

Successfully implemented Fourier transform and convolution in RF domain

Validated RF calculation in radar scenarios for target detection

Demonstrated improved precision and efficiency over traditional methods

Abstract

Information metasurfaces have emerged as pivotal components in next-generation electronic systems, with significant progress in their applications to communication, radar, and sensing. However, the current researches are mainly focused on their physical structures and system functions, while radio-frequency (RF) signal processing and calculation remain constrained to digital-domain operations. This reliance on digital conversion inherently increases hardware complexity and power consumption. To address this challenge, we propose a programmable RF calculation system based on a space-time-coding metasurface (STCM), which can control the wave-matter interactions through space-time-coding (STC) strategies and achieve direct RF calculations in the electromagnetic (EM) space in a reprogrammable way. Particularly, the fundamental signal operations - Fourier transform and convolution - are implemented in the EM-wave domain successfully. We validate the RF calculation capabilities in radar scenarios, facilitating the accurate detection of target velocity and range. Theoretical analysis, numerical simulations, and experimental results collectively demonstrate that the STCM-based RF calculation system exhibits superior precision, enhanced operational efficiency, and notable cost-effectiveness, highlighting its significant potentials for the next-generation electronic system deployments.