Ultrathin Metamaterial-Inspired Huygens Dipole Antenna and Rectenna Arrays for Wireless Power Transfer Enabled IoT Applications

Abstract

Ultrathin metamaterial-inspired Huygens dipole antenna and rectenna arrays are presented for wireless power transfer (WPT) enabled IoT applications. The fundamental array element is the electrically small Huygens dipole antenna (HDA) that consists of two metamaterial-inspired structures: an Egyptian axe dipole (EAD) and a capacitively loaded loop (CLL). The EAD and CLL are designed on both sides of a single PCB substrate functioning as the in-phase and orthogonal electric and magnetic dipoles. A short-driven dipole close to the CLL excites the two radiators. Based on the single element HDA, an ultrathin, beam-steerable Huygens dipole antenna array (HDAA) with wide area coverage and small gain variation has been developed as a long distance WPT transmitter for battery-free applications. Experimental verifications of the simulated results are presented. Additionally, an HDA-based Huygens dipole rectenna array (HDRA) design is developed for the receiver side. Effective capture of the wireless energy to power IoT devices is illustrated. Both DC and RF combining schemes are discussed for different application scenarios.