Conformal Near-Field Focus Radiation from Phased Array of Antennas to Enhance Power Transfer between Transmitting and Receiving Antennas
Journal
IEEE Transactions on Antennas and Propagation
Journal Volume
68
Journal Issue
5
Pages
3567-3577
Date Issued
2020
Author(s)
Abstract
In this article, the concept of conformal near-field focus (CNFF) radiation from a phased array of antennas is theoretically presented. The motivation intends to enhance the electromagnetic (EM) power reception by receiving antennas (RXAs) of relatively large sizes. Instead of enforcing an equal-phase radiation focusing at a single NFF point, which loses the freedom of phase control, the CNFF concept considers the wavefront of RXA radiation to design a CNFF antenna (CNFFA) for better power transfer. Its radiation produces a proper phase distribution in a customized fashion, which is conformal to the wavefront of selected RXA's radiation in the near-zone. The development considers power transfer between the CNFFA and RXA by defining a convenient power reaction factor (PRF) on the reaction equation, which naturally constructs a relationship between the CNFFA's excitations and an RXA. The intention to maximize the PRF in the reaction equation results in the conformal radiation characteristics of the CNFFA. In this study, the concept and design guidelines are presented, which are validated via theoretical and numerical simulations of practical examples. This concept is particularly useful for wireless power transfer at high frequencies where geometric optic (GO) interpretation of wave propagation is valid.
Type
journal article