SAR Imaging Modulation Based on Time-Modulated Corner Reflector With Wide-Angle Domain Control
Guang Sun, Liwen Zhu, Shiqi Xing, Junjie Wang, Dejun Feng, Xuesong Wang
Abstract
Time-modulated metasurfaces (TMMs) can dynamically control the electromagnetic (EM) wave in real-time, holding extraordinary potentials in the radar imaging modulation. However, achieving monostatic radar cross section (RCS) control in a wide-angle domain for traditional planar TMM poses considerably challenging. In this letter, a time-modulated corner reflector (TMCR) with periodic modulation based on the TMM is proposed to manipulate the spectrum distribution for countering synthetic aperture radar (SAR) imaging. The TMCR can flexibly control incident EM waves in real time, with excellent wide-angle domain stability and polarization insensitivity. The amplitude of the echo signal is dynamically controlled by applying periodic encoded waveforms to generate a discrete Doppler spectrum. Based on this, multiple discrete false targets around the actual target appear in SAR imaging. The simulation and experimental results demonstrate that the proposed TMCR has excellent EM modulation capability in the azimuth range of 0°–75° and pitch range of 0°–45°, enabling the monostatic RCS modulation in a wide-angle domain. Moreover, it can generate multiple false targets in the range direction of the radar, illustrating the validity of the proposed structural design.