School of Electronics, Electrical Engineering and Computer Science
& ECIT Global Research Institute
Proposed Project Title: Novel Rectenna for Energy Harvesting and Wireless Power Transmission
Principal Supervisor: Dr Mury Thian Second Supervisor: Prof William Scanlon (tbc)
Wireless power transmission (WPT) techniques provide attractive alternative for generating clean and renewable power source through harvesting ambient electromagnetic energy, and hence present a promising scheme for wireless power charging and battery-free solutions in numerous applications. One of the applications is for structural monitoring where RF powered devices are embedded into a structure rendering battery replacement impossible without destroying the structure. Further, some applications require deployment of RF powered devices in large quantity, thus making individual node battery replacement impractical. Other applications include biomedical implants in which the chance of getting infection from surgeries performed regularly to replace the battery can be eliminated.
There are three fundamental WPT techniques, i.e., close-range induction technique, mid-range magnetically coupled resonance technique and far-field rectification technique. The last technique typically employs a rectenna circuit which is comprised of a receiving antenna and a rectifier/RF-to-DC converter. The rectenna performance is primarily determined by the gain of the antenna and the efficiency of the rectifier. Therefore, a proper choice of the antenna structure and the rectifier topology are crucial.
When RF powered devices harvest their power from RF wave radiation, a radiating source or base station is required to transmit a high-intensity RF signal wirelessly through the air. The high-intensity RF signal is then picked up by a receiving antenna on the sensor and the RF signal is converted to a DC voltage. The DC voltage is subsequently stored on a holding capacitor and supplies power to the integrated circuits. It is of paramount importance that the RF-to-DC converter can operate efficiently at very low received power to achieve long operating distance. One of major challenges is that when the available RF power to the receiver is smaller than 100 μW the available voltage for rectification in the RF to DC conversion falls below 0.3 V, much too low to overcome the threshold voltage of conventional rectifier circuits. To overcome this problem, a more sophisticated circuit the so-called voltage multiplier can be used but the efficiency of such circuit is relatively poor.
The core objectives of the project are:
- To develop and design a novel rectifier circuit including a voltage multiplier that can operate efficiently with low input voltages and a capacitor bank to store the DC energy.
- To investigate various types of antennas suitable for WPT.
- To investigate design trade-offs in rectenna design, e.g., antenna size and radiation gain, rectifier complexity and efficiency, etc.
Supervisor Name: Dr Mury Thian Tel: +44 (0)28 9097 1845
QUB Address: Email: firstname.lastname@example.org
Belfast BT3 9DT