5G as a wireless power grid

Abstract

Abstract5G has been designed for blazing fast and low-latency communications. To do so, mm-wave frequencies were adopted and allowed unprecedently high radiated power densities by the FCC. Unknowingly, the architects of 5G have, thereby, created a wireless power grid capable of powering devices at ranges far exceeding the capabilities of any existing technologies. However, this potential could only be realized if a fundamental trade-off in wireless energy harvesting could be circumvented. Here, we propose a solution that breaks the usual paradigm, imprisoned in the trade-off between rectenna angular coverage and turn-on sensitivity. The concept relies on the implementation of a Rotman lens between the antennas and the rectifiers. The printed, flexible mm-wave lens allows robust and bending-resilient operation over more than 20 GHz of gain and angular bandwidths. Antenna sub-arrays, rectifiers and DC combiners are then added to the structure to demonstrate its combination of large angular coverage and turn-on sensitivity—in both planar and bent conditions—and a harvesting ability up to a distance of 2.83 m in its current configuration and exceeding 180 m using state-of-the-art rectifiers enabling the harvesting of several μW of DC power (around 6 μW at 180 m with 75 dBm EIRP).

Millimeter Wave Power Transmission for Compact and Large-Area Wearable IoT Devices based on a Higher-Order Mode Wearable Antenna

“…2) Conformable and low antenna profile for improved integration in clothing and on thinner substrates [21]. 3) Broad bandwidth, to enable the antennas to be used in the full 5G spectrum [12], [17]. While several theoretical and practical studies have shown the benefits of mmWave WPT [4], [9], [12], the performance of a mmWave-powered network based on a real antenna, meeting the above criteria, remains unclear.…”

“…3) Broad bandwidth, to enable the antennas to be used in the full 5G spectrum [12], [17]. While several theoretical and practical studies have shown the benefits of mmWave WPT [4], [9], [12], the performance of a mmWave-powered network based on a real antenna, meeting the above criteria, remains unclear. To explain, the benefits of mmWave WPT compared to its UHF counterpart need to be evaluated.…”

“…mmWave WPT from an off-body source can be utilized in future mmWave micro-cells in vehicle-to-anything (V2X) as well as indoor applications, where many IoT devices are expected to be powered simultaneously. Based on the measured sensitivity of practical rectifiers [4], a WPT range of 10 m can be achieved based on the FCC-specified 75 dBm EIRP for the 5G mmWave bands [12], [17].…”

Advances in Wirelessly Powered Backscatter Communications: From Antenna/RF Circuitry Design to Printed Flexible Electronics

“…Such solutions are impractical and inefficient, especially with the deployment of billions of IoT devices in arbitrary locations and over a large city. Eid et al [99] proposed a system capable of harvesting the 5G/mm-wave energy from all directions, thereby breaking the aforementioned tradeoff of simultaneous high gain antennas and wide angular coverage. To realize this, the authors incorporated a fully printed planar Rotman lens in their rectenna design, as an intermediate element between the antenna arrays and the rectifiers.…”

Backscatter Communications

“…The Rotman lens is a unique type of passive BFNs that combines all the power received on its antenna ports, on one side, and focuses it towards the beam port(s) associated with the direction of arrival of the signal. Depending on the intended use, rectifiers such as in [54], [55] can be placed at the beam ports to collect the RF power and convert it to DC, or switches such as in [56] can be connected to modulate the signal and reflect it back for communication purposes. Unlike the Van Atta structure that divides the power among its lines and is, therefore, ill-suited for optimal harvesting performance, the Rotman lens-offering RF combination-can enable the operation of fully-passive RFID tags at longer turn-on ranges, if rectifiers are connected to the beam ports to power the tag.…”