A Scalable High-Gain and Large-Beamwidth mm-Wave Harvesting Approach for 5G-Powered IoT
In this effort, the authors demonstrate for the first time the implementation of a Rotman-Lens-based rectenna system for mm-wave harvesting, in the 28GHz band. The structure merges unique RF and DC combination techniques, for the realization of rectennas that display the unlike combination of high gain and large beamwidth. The Rotman-lens-based rectenna includes components — antennas, rectifiers, Rotman lens, and power combining network — whose design is first presented and performance is experimentally characterized and verified. Then, the fabrication and testing of the device, and that of a reference design — comprising a DC-combined array of rectennas of equal aperture — is presented. The novel Rotman-based rectenna harvester shows a 21-fold increase in the harvested power compared to its reference counterpart, while its angular coverage remains identical. The structure, therefore, demonstrates the surprising combination of high-gain and large beamwidth, thereby potentially enabling the emergence of passive long-range mm-wave RFIDs.