3D integrated high gain rectenna in package with metamaterial superstrates for high efficiency wireless power transfer applications

摘要

This paper first presents a 3D integrated high gain rectenna in package with metamaterial (MTM) superstrates for a high efficiency wireless power transfer (WPT) application which operates at 2.45 GHz. The integrated rectenna is composed of 3 layers where the first layer is an MTM superstrate consisting of 4 by 4 MTM unit cells (the size of the unit cell: $mathrm{27.5}imes mathrm{27.5} ext{mm}^{mathrm{2}}$), the second layer a patch antenna ($mathrm{36.1}imes mathrm{27.9} ext{mm}^{2}$), and the third layer a rectifier ($mathrm{54.2}imes mathrm{16.3} ext{mm}^{mathrm{2}}$). By integrating the MTM superstrate on top of the patch antenna, the gain of the antenna is enhanced due to its focusing capability, resulting in the increase of incident RF power at the rectifier input thereby inducing high output DC power and high end-to-end efficiency. A prototype 3D integrated rectenna is designed, fabricated and characterized. It shows a gain improvement of 5.8 dB compared to a counterpart patch antenna without an MTM superstrate, and a maximum RF-DC conversion efficiency of 63.5% at an input RF power of 10.5 dBm. This results in the improvement of the RF-DC efficiency from 56.8% to 63.5% and the increase of the output DC power from 1.6 mW to 6.35 mW (a factor of 3.97 improvements).