Scalable Electromagnetic Energy Harvesting Using Frequency-Selective Surfaces

We present a frequency-selective surface (FSS) that is specially designed and optimized for ambient RF energy harvesting. The unit cell geometry incorporates channeling features in order to combine the collected power from multiple unit cells, allowing for efficient operation under low-power conditions. To demonstrate its performance, we designed and fabricated a matched full-wave rectifier integrated with the absorber FSS. Radiated measurements for the complete rectenna system are included in this paper demonstrating strong agreement with the simulation results. The proposed periodic structure absorbs 97% of the available energy at its resistive load, thus making it an ideal candidate for energy harvesting and channeling applications. Overall Radiation-to-dc conversion efficiency of the fabricated prototype was measured to be 61% when the collected power at the rectifier was 15 dBm.