Efficient and Sensitive Electrically Small Rectenna for Ultra-Low Power RF Energy Harvesting

Abstract

A new electrically small antenna with size ka = 0.415 is presented, fabricated and measured in this work. This is intrinsically matched to 50 Ω, has omni-directional and linear-polarized radiation pattern in the horizontal plane with maximum directivity of 1.75 dBi and simulated radiation efficiency of 93%. The antenna in combination with a low-complex and co-planar rectifier with one single diode forms a high efficient and sensitive electrically small rectenna with ka = 0.53 at 868 MHz (UHF RFID-band in Europe). The latter has measured efficiency 22.5% for −19 dBm power input and sensitivity of −44 dBm (or equivalently 0.00028 μW/cm2 power density), while at 2.25 μW/cm2 is able to supply continuously, i.e., without a boost converter or use of any energy tank, a small electrical device with 118 μW. In order to increase the dc output voltage and the delivered dc power to the load for lower power density levels, rectenna-array configuration is exploited. Application to batteryless, backscatter wireless sensor node powering is discussed. Specifically, for a power density of 0.1237 μW/cm2 the RF energy harvesting system delivers 172 μW at 2.85 V every 22.5 s.

Wide-angle, wide-band, polarization-insensitive metamaterial absorber for thermal energy harvesting

“…However, their relatively high cost and low conversion efficiency at lower temperatures impedes their use at large scale 10 . A promising technique is the rectifying antennas (rectennas) which have been implemented successfully in the microwave regime with high efficiency 11 . The rectenna is comprised of a rectifying element which is the diode connected to the terminals of a receiving antenna designed to resonate around the peak of the incoming electromagnetic radiation 9 .…”

Design of a Rectenna Array Without a Matching Network

“…Such rectenna system is an integral and critical part of Wireless Power Transfer systems (WPT). Since their main goal is to deliver energy wirelessly to a load, rectennas enabled numerous applications such as Space Solar Power [1], [2], energy harvesting/scavenging [3]- [5], remote sensing [6], [7], Internet Of Things (IOT) [8]- [10], wireless battery charging [11], and infrared detection [12], [13].…”

A high Q piezoelectric resonator as a portable VLF transmitter

“…A significant challenge for ESAs with a wavenumber-length product much <1 is a high radiation Q, Q A , which considerably limits the radiation efficiency 5,6 . In a lossy antenna, the total Q is Q t = 1/(1/ Q m + 1/ Q A ) where Q m encompasses all non-radiation losses within the antenna system.…”