Millimeter-Wave Integrated Rectenna and Arrays Based on Planar Aperture Antenna With High Conversion Efficiency Under Low Incident Power Densities

Abstract

A novel integrated rectenna based on planar aperture antenna (PAA) working at 35 GHz without extra matching network between the antenna and rectifier is proposed in this letter. The PAA simultaneously serves as both the power receiving device and the impedance matching network of the diode, thus eliminating insertion loss of the matching network. Meanwhile, more RF power can be collected at a low incident power density because of a PAA featuring a high gain. These lead to a high RF-to-DC power conversion efficiency (PCE) of 53.1% at a low power density of $7.46\text{mW}∕{\text{cm}}^2$, surpassing that of most millimeter-wave (MMW) rectennas. Moreover, the rectenna features a simple structure with only one laminate and thus low fabrication cost. Furthermore, multiple rectenna elements are arranged in a sequential rotation manner and their output DC power is aggregated through DC power combining, forming two dual linearly polarized (DLP) rectenna arrays with $2\times 2$ and $4\times 4$ elements. When the polarization of the incident wave changes, the measured PCE of the $2\times 2$ and $4\times 4$ array ranges from 34.7% to 55.6% and from 23.6% to 48.6%, respectively, demonstrating that they are less sensitive to polarization variations than linearly polarized ones.