Reconfigurable Reflectarray Antenna Based GeTe Phase-Change Material in the Ka-Band

This paper introduces a 1-bit broadband digital metasurface unit based on the phase-change material(PCM) GeTe in the Ka-band. The metasurface unit achieves a stable phase shift of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$180^{\circ}+25^{\circ}$</tex> within the frequency range of 27.87GHz to 41.99GHz, with a bandwidth of 14.12GHz and a relative bandwidth of 40.42%, exhibiting stable broadband characteristics and reflection losses below 0.45dB. A 15×15 array based on this metasurface unit is designed, and simulations demonstrate that the antenna can achieve a wide-angle scanning of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 50^{\circ}$</tex> with excellent beam scanning performance, reaching a peak gain of 17.57dBi.