Title: A Highly Efficient Polarization-Independent Metamaterial-Based RF Energy-Harvesting Rectenna for Low-Power Applications,
Abstract: A highly-efficient multi-resonant RF energy-harvesting rectenna based on a
metamaterial perfect absorber featuring closely-spaced polarization-independent
absorption modes is presented. Its effective area is larger than its physical
area, and so efficiencies of 230% and 130% are measured at power densities of
10 uW/cm2 and 1 uW/cm2 respectively, for a linear absorption mode at 0.75 GHz.
The rectenna exhibits a broad polarization-independent region between 1.4 GHz
and 1.7 GHz with maximum efficiencies of 167% and 36% for those same power
densities. Additionally, by adjustment of the distance between the rectenna and
a reflecting ground plane, the absorption frequency can be adjusted to a
limited extent within the polarization-independent region. Lastly, the rectenna
should be capable of delivering 100 uW of power to a device located within 50 m
of a cell-phone tower under ideal conditions.