A Highly Sensitive Broadband Rectenna for Low Power Millimeter-wave Energy Harvesting Applications

In this paper, a highly sensitive broadband millimeter-wave energy harvesting rectenna has been designed, fabricated, and experimentally investigated. The proposed structure includes a high gain 8-by-1 gap-coupled antenna array and a zero-bias Schottky diode rectifier circuit, to efficiently convert RF to DC signal. In order to further characterize the antenna array circuit, both structures (antenna and rectifier) are individually implemented on thin-film ceramic substrate (ε
_r
= 9.9, h = 127 μm), using an MHMIC (Miniature Hybrid Microwave Integrated Circuits) fabrication process. Then, they are joined together using low-loss wideband waveguide (WR12) to microstrip transitions in order to validate the investigated rectenna configuration. A maximum measured RF to DC conversion efficiency of 49.3 %, and sensitivity level of around -60 dBm were successfully achieved. These results make the proposed rectenna structure an excellent candidate for low power millimeter-wave energy harvesting.