AU2018100012A4

AU2018100012A4 - An IoT Based Ambient Energy Harvester

Info

Publication number: AU2018100012A4
Application number: AU2018100012A
Authority: AU
Inventors: Mehran Abolhasan; Justin Lipman; Negin Shariati Moghadam; Farzad Tofigh
Original assignee: Infinite Sensing Pty Ltd
Current assignee: Infinite Sensing Pty Ltd
Priority date: 2018-01-08
Filing date: 2018-01-08
Publication date: 2018-02-15
Anticipated expiration: 2026-01-08

Abstract

An autonomous sensor and/or loT device capable of operating on harvested energy, sensing the environment and transmitting sensed data to the cloud using wireless communication link. The autonomous sensor/loT device may be integrated with multiple sensors/loT devices, a logic unit and a radio transmitter to transmit sensory data to the cloud/server for monitoring or analytic purposes. The sensor system includes one of electrical, magnetic, electromagnetic, acoustic, optical, mechanical, chemical, thermal and flow sensor.

Description

Dependency of loT devices on batteries is a significant shortcoming for their wide scale adoption. Radio frequency energy harvesting is a promising solution to provide a sustainable energy source for autonomous loT devices. Over the past few years, RF energy harvesting has experienced a significant growth in innovation resulting in developments of various RF harvesting prototypes. This is mainly driven by the ever increasing number of RF transmitters, which are producing an abundant of ambient microwave energy waste, which is seen as an opportunity to harvest for low-power loT devices. Furthermore, the development of wireless power transmission (WPT) technologies that allow maintenance-free and mobile electronic devices to operate without batteries has further triggered impetus for RF energy harvesting. A prominent advantage of RF scavenging is the ability to convert RF energy into electrical power throughout day and night, both outdoors and indoors. Therefore, RF energy harvesting has the potential to generate a viable energy source for low-powered loT devices anywhere and anytime with the added benefit of being environmentally friendly.

Efficient RF energy harvesting is a very challenging issue, as it must convert low RF power levels available in the environment to electrical energy. Furthermore, the scavengable power level can vary unpredictably, depending on several factors such as the distance from the power source, the transmission media, the telecommunication traffic density and the antenna orientation. The majority of available literature on RF harvesting has been dedicated to narrow-band rectennas, which essentially operate at a single frequency and hence provide low DC output power. Flowever, to increase the amount of RF energy scavenged by a rectenna, it is crucial to identify and harvest multiple ambient frequency sources simultaneously.

This invention claims a design for a highly sensitive and efficient rectenna that can harvest specific frequencies (from ambient or dedicated RF sources) where maximum signal power is available, enabling greater power harvesting.

In addition a boost circuit design is proposed to convert the rectifier voltage to the voltage of a battery. This invention has been devised in order to provide a novel RF energy harvesting system employing ambient RF energy scavenging or WPT techniques. RF energy can be diffracted from and penetrate inside building materials. Therefor it is possible and practical to create structural panels with the proposed EFI system embedded into common building materials such as roof tiles, plasterboard and concrete to provide energy to wireless sensors. The structural panels can be integrated into existing building structures, creating a novel structurally integrated independent energy scavenging scheme.

In this patent, a unique low-cost energy harvesting system is proposed that can be embedded into loT devices to minimise their dependencies on batteries. Further the proposed solution can also be embedded in various construction and end-user product materials.

Claims

Claims:

1. An autonomous sensor and/or loT device capable of operating on harvested energy, sensing the environment and transmitting sensed data to the cloud. • The autonomous sensor/loT device described above, extended and integrated with multiple sensors/loT devices, a logic unit and a radio transmitter to transmit sensory data to the cloud/server for monitoring or analytic purposes. • The autonomous sensor described in this claim, generates a signal corresponding to a sensed condition and transmits a corresponding signal via a wireless communication link to the cloud/server/distributed sensors. • The sensor system of claim 1 includes one of electrical, magnetic, electromagnetic, acoustic, optical, mechanical, chemical, thermal and flow sensor.
2. Energy Harvester system described in claim 1, comprised of a compact rectenna (combination of an antenna, rectifier), and DC/DC converter etched in or on a substrate plus electronic components (lumped components or microstrip) covering one or multiple frequencies simultaneously for electromagnetic energy harvesting. • The Energy Harvester system described in this claim capable of harvesting RF energy from a focused beam and/or other sources available in the environment. • In this claim, directed electromagnetic energy is directly converted to electricity to recharge the onboard batteries or supercapacitors, to extend the operating time of autonomous loT devices, wireless sensors and unmanned aerial vehicles (UAVs). • The Energy Harvester system described in this claim allows for harvesting of multiple frequency bands simultaneously. Wherein each frequency band consists of several frequencies. • Multi-band technique provides maximum power transfer from the antenna to the rectifier circuit using RF combining technique. The technique can provide higher DC power than combining two separate single frequency rectifier circuits operating at the same frequencies. • Rectifier described in this claim, is capable of harvesting RF signals (ambient or transmitted signal) from multiple frequency bands across a broad range of spectrum (50 MHz to 3 GHzl • Rectifier described in this claim is highly sensitive and is capable of harvesting RF signals over a broad range of very low and medium power levels from 0.001 pW to 10 mW (-60 to 10 dBm). • Rectifier described in this claim consists of at least one rectifying device (diode or transistor) or multiple rectifying devices to create voltage doubler/multiplier topologies. • The Energy Harvester system described in this claim consists of a multi resonator matching network with an optimum bandwidth at each operating frequency band. Depending on the frequency band, the matching network is designed using lumped components or microstip lines. • The Energy Harvester system described in this claim consists of a single band/ multiband/broadband very compact antenna(s) capable of receiving multiple frequency bands concurrently. • Antenna described in this claim, is embedded in/on substrate as an integrated part of the described rectifier in claim 2 • Antenna described in this claim, is circularly polarized and highly sensitive antenna with high gain which is capable of harvesting RF signals with different polarizations over a broad range of very low and medium power levels.
3. The multi-resonator RF Energy Flarvester system described in claim 2 can be integrated with multiple RF energy harvesters to create multi-resonator rectenna arrays. • The rectenna array in this claim allows to harvest multiple frequency bands such as broadcasting (FM radio, digital and analogue TV), cellular systems, WiFi. • Each module consists of several rectennas, while each rectenna consists of multi-resonators. This allows for maximising energy harvesting.
4. The RF Energy Harvester system described in claim 2, can be embedded into structural panels composed from common building materials such as roof tiles, plasterboard and concrete to provide energy to wireless sensors. The structural panels can be integrated into existing building structures, creating a novel structurally integrated independent energy scavenging scheme. • In this claim, the RF energy harvester will be part of the existing building/bridge/tunnel structure and there is no need for an external panel to be mounted on a building/bridge/tunnel, the rectenna will be part of the existing structure.
5. The Energy Harvester system described in claim 2, can be embedded into the skin of autonomous systems such as UAVs (hard-integrated system, fibre reinforced composites). • The embedded rectenna described in this claim can harvest RF energy to charge batteries or supercapacitors, hence extending the operating time of UAVs and reducing the need for UAVs to carry extra batteries which add weight and potentially eliminating the need for these systems to return to base for recharging.