Actively tunable terahertz coding metasurfaces

Lately, programmable metasurfaces have been proposed by adding a PIN diode between two metallic patches in microwave region. However, the pin-diode switches can only operate at relatively lower frequencies (< 60 GHz), the conventional electronic method of device design used in the microwave band cannot easily be extended to the terahertz frequency regime. Here, we describe a new design principle for the actively tunable terahertz wave coding metasurfaces using vanadium dioxide embedded metallic patch. The radar cross section (RCS) reduction and radiation patterns of our new coding scheme can be altered using the metal-insulator transition of vanadium dioxide at around 68 degrees C. To the best of our knowledge, this is the first time that an active control of programmable coding metasurfaces was demonstrated at terahertz regime.