3D-Printable Rectenna for Passive Tag Localization Exploiting Multi-Sine Intermodulation

This work presents the design of a dual mode rectenna, combining energy harvesting and passive localization, based on low-cost (lossy) materials (here, polylactic acid), suitably processed through 3D printing technologies, to offer performance comparable to those of standard materials for RF. An optimized etching of the substrate is proposed, consisting of a honeycomb core with octagonal cells, which allows to mitigate RF losses and to preserve mechanical stability. Based on the etched material, a narrowband antenna at 2.4 GHz and an ultrawideband (UWB) one are designed to be the input and output terminations of a rectifier, the latter in parallel connection with the rectifier dc path. Design specifications are the maximization of both the RF-to-dc efficiency and the power contents at the second, third, and fourth harmonics generated by the rectifier nonlinearities under multi-tone excitation. In this way, a passively-generated UWB signal is radiated by the UWB antenna for localization purposes.