Abstract: The disclosed technology includes device, systems, techniques, and methods for mm-wave energy harvesting utilizing a Rotman-Lens-based rectenna system. An energy harvester system can include one or more antenna, a Rotman Lens having a beam port side and an antenna side in electrical communication with the one or more antenna, and a rectifier network in electrical communication with the beam port side of the Rotman Lens. The energy harvester system can also include a power combining network in electrical communication with the rectifier network and having an output. The rectifier network can include a plurality of rectifiers connected to the beam port side of the Rotman Lens. Further, each of the plurality of rectifiers can include a rectifying diode. The power combining network can include a plurality of bypass diodes.