Stepped‐Frequency Linear‐Frequency‐Modulation Radar Transmitter Architecture Based on Space‐Time‐Coding Metasurface

ABSTRACT The rapid evolution of electronic information systems has rendered the development of radar transmitters featuring low architectural complexity and frequency agility imperative. Space‐ time‐coding metasurface (STCM) has emerged as a promising platform for optimizing coding strategies in spatial and temporal domains to enable precise beamforming and sophisticated waveform generation, providing innovative solutions for radar systems. Nonetheless, the frequency modulated bandwidth of the STCM‐enabled radar systems is restricted to no more than 1 MHz, which results in insufficient spatial resolution and renders the practical applications. To address this constraint, we propose a stepped‐frequency linear‐frequency‐modulation (SF‐LFM) architecture based on STCM and develop a broadband STCM radar system. By synthesizing the discrete narrowband frequency‐ modulated signals regulated by STCM into a coherent wideband detection waveform, the radar system achieves two orders of magnitude expansion in frequency‐modulation bandwidth (from 1 to 256 MHz), thus enabling decimeter‐scale range resolution for high‐precision target localization. This architecture not only facilitates the joint estimation of target range and velocity with decimeter‐level accuracy but also integrates the capability of dynamically reconfigurable beamforming. The proposed SF‐LFM radar transmitter merges low hardware complexity with high‐precision detection performance, holding promise for next‐generation electronic systems in autonomous sensing, industrial monitoring, and beyond.