As Wireless Sensor Network (WSN) cannot be deployed in hard-to-reach places where battery cannot be replaced or the need to replace the battery becomes a very tedious and time consuming exercise. With Radio Frequency (RF) energy harvesting, the dependency on battery to power the Wireless Sensor Network is reduced or the use of battery can be totally eliminated in the near future. Combining with Wireless Power Transfer (WPT), power can be transferred wirelessly without any physical connectivity to the sensors or nodes of the Wireless Sensor Network.
The project has shown the ability to harvest the RF energy off-air and to transfer power remotely to the Wireless Sensor Network.
Besides conserving power with low power electronics and communication protocol design, topping up power to the sensor node via wireless charging present a major opportunity for innovation.
Over the years, our team has been actively conducting R&D projects on Wireless Power Transfer since 2010. We have filed a patent filed in 2014, which outlined a novel received-side antenna coil design that increases its Q-factor (resonance), resulting in range extension between the transmitter and receiver. This unique design lies on the way of coiling the receiving antenna to have high Resonance (Q) as high Q simply means more energy can be harvested.
We have researched, developed and demonstrated the ability to harvest the RF energy off-air with our RF energy harvesting system. The harvested RF energy is converted to DC energy and store in a battery. The stored energy can be used to power low power devices like the WSN sensor node.
We have also developed a WPT prototype to top up the batteries of the WSN wirelessly over a distance for:
The application for WPT is very wide and is not just limited to livestock or environmental monitoring. For example, vehicles moving over track can receive power through the WPT system. The transfer of power wirelessly has the potential to completely disrupt and revolutionize existing and future technology.
This reduction in both size and power of complex electronics have made it possible for such small devices like wearable and WSNs to be battery operated while able to perform complex task. However, batteries present several disadvantages when it comes down to the size and weight and the needs to be replaced periodically. With the continuous reduction in size and power for the complex electronics, it may not be long before all small and portable devices can harvest sufficient energy from the environment to power the electronics. RF energy harvesting or WPT may someday be a viable complete source of energy for small portable electronics wearables and devices.
RF energy harvesting can potentially replace the dependency on batteries for low power electronics devices like those in the WSN. The wide-spread deployment of WSN in environmental monitoring and data collection services also implies the need to replace the batteries for the WSN on a continuous basis which is both time consuming and tedious. The objective of using the RF energy harvesting and WPT is to eliminate this dependency on battery for the WSN.
With RF energy harvesting, potential devices can be trickle charged to boost up the batteries and WPT can be used to charge up the battery when not in used.
In combination, these developments have sparked interest in the engineering community to develop more and more applications that utilize energy harvesting or WPT to top up the battery for IoT sensors.