Time Modulated Metasurface in X‐Band for Radar Countermeasure

This study presents the design and implementation of reconfigurable metasurface time modulation in the X‐band. Three layers form the time‐modulated metasurface, with the middle layer switchable ground. The switching behavior of the PIN diode changes the reflection coefficient over time. Time‐modulated complex‐valued reflection coefficients produce harmonics with reduced reflected frequency component power and increased side‐band power. The harmonic with reduced incidence frequency component power offers extra frequency shift and incorrect velocity information to X‐band Doppler radar. A prototype with a thickness of 0.12 and a periodicity of 0.26 (the lowest frequency) is proposed. In the frequency range of 7.8–12.9 GHz, the measured spectrum of the reflected electromagnetic wave component at ranges from −0 to −17 dB. The authors claim this is the first experimental proof of a time‐modulated metasurface in the 7.8–12.9 GHz frequency range (X‐band). The structure can disrupt X‐band Doppler radar target recognition and tracking with a Doppler‐like frequency shift in the reflected wave.