3DlInkjet-printed Origami Antennas for Multi-direction RF Harvesting

A system design is presented for radio frequency (RF) energy harvesting on wireless sensor network (WSN) nodes, where all electronics reside inside a 3D structure and the antennas lie on the surfaces of it. Additive manufacturing techniques are used for the packaging and antenna fabrication: A 3D-printed cross-shaped structure is built that folds to a cuboid in an “origami” fashion and retains its shape at room temperature. Inkjet printing is used to directly fabricate antennas on the surfaces of the 3D-printed plastic, enabling a fully additive manufacturing of the structure. Multiple antennas on the cube's surfaces can be used for RF energy harvesting of signals arriving from totally orthogonal directions, with the use of an appropriate harvester. The system modules (cube, antenna, harvester) are described and characterized, offering a proof-of-concept for the combination of fabrication techniques to build systems for demanding RF applications.