Tri-band miniaturized wide-angle and polarization-insensitive metasurface for ambient energy harvesting

In this paper, a tri-band miniaturized wide-angle and polarization-insensitive metasurface is proposed as an ambient energy collector. The metasurface is composed of a subwavelength butterfly-type closed-ring (BCR) array attached to a low-loss substrate with a metallic ground. Each unit cell of the energy harvesting metasurface has only one harvesting port. Its energy harvesting efficiency for different polarization and incident angles was analyzed, and the results show that the maximum harvesting efficiency is 90%, 83%, and 81% at the three frequency bands of 0.9 GHz, 2.6 GHz, and 5.7 GHz, respectively. Moreover, a prototype of the 7 x 7 BCR metasurface harvesting array was fabricated and measured. The experimental results validate that the proposed metasurface performs well under transverse electric and transverse magnetic polarization and is suitable for wide-angle incident energy harvesting in the three frequency bands. Published by AIP Publishing.