Design rules for innovative nano-rectennas in the infrared region

In this paper, we investigate several rectenna architectures to exploit THz energy sources in the infrared (IR) region for a twofold purpose in energy-aware RFID applications: on one hand to harvest from solar energy, on the other hand to wirelessly receive power from dedicated infrared sources on an as-needed basis. The crucial role of the radiating portion is deeply discussed. A tunnel metal-oxide-metal (MOM) diode is used to rectify THz power: by means of a nonlinear/electromagnetic (EM) approach a prediction of the entire nano-array rectenna performance is proposed, focusing on the maximization of the antenna efficiency and on the accurate description of the diode nonlinear behavior. Accurate modeling of materials, antenna layouts, and nonlinear devices are developed and the main shortcomings are highlighted. Bow-tie-shaped radiating elements are chosen and rectenna arrays based on misaligned printed dipoles or, alternatively on coplanar slots are analyzed and compared in terms of radiation properties and losses related to the adopted layout. With this approach, an accurate estimation of the overall system performance in terms of THz-DC conversion efficiency is provided.