Projects:2014S1-12 Exploring RF Energy Harvesting for Wearable Sensors

Project information

Introduction

Wearable electronic devices are widely used in number of areas. The project aims to provide battery-like DC energy to low power wireless sensors by harvesting the ambient RF energy using flexible antenna and convert it through a rectifier circuit. Essentially, the antenna receives ambient radio frequency signals from mobile communication channels GSM900 and GSM 1800. The harvested energy will be then transmitted to corresponding rectifier circuits and the converted output DC energy. The output DC energy is designed to be sufficient large to drive low power sensors.

System Overview

Background

A radio-frequency (RF) energy harvesting device, often referred as a rectenna, is used to convert RF energy into direct current electricity. Early rectenna researches have been done in the area of high-power beaming transmission, while more recent trends have extended to ambient microwave energy recycling [1]. With growing interest of continuous physiological signal monitoring via low power sensors as well as explosive growth of cellular mobile communications making use of large amount of base stations, rectenna applications recycling microwave energy within mobile frequency band have been made available.

Design Target

• Design and manufacture a dual-band patch antenna that is able to collect the ambient RF energy with the frequencies of GSM900 and GSM1800.
• Design and manufacture a wide-band dipole antenna that is able to collect the ambient RF energy with the frequencies of GSM900 and GSM1800.
• Design and manufacture a rectifier which is able to convert the RF energy of GMS900 and GMS1800 into DC energy.

Design Approach

• Understand the basic approach to design antennas and the circuit of rectifiers.
• To design antennas
  • HFSS is used during the design process
  • Draw a parametric model in HFSS
  • Obtain simulated results
  • Analyse simulated results and hence optimise the design
  • Test the limitation of the dimension accuracy in manufacturing and human body effects in HFSS
  • Manufacture the antenna and test the performance
• To design the circuit of the rectifier
  • ADS is used uring the design process
  • Design the system in top level.
  • Design the circuit to obtain the value of each component.
  • Optimize the schematic-based design in ADS
  • Layout the schematic design
  • Process EM simulation
  • Use ADS to do EM Optimisation
  • Manufacture the circuit and test its performance

Team

Group members

• Mr Mingzhe Li
• Mr Hung-Kai Mai
• Mr Hanqing Wang

Supervisors

• Dr Thomas Kaufmann
• Prof Christophe Fumeaux

Resources

• Bench 22 and 23 in Projects Lab
• Voltage Control Oscillator
• DC generator
• Network Analyser
• Anechoic Chamber
• Spectrum Analyser
• Software
  • ANSYS HFSS
  • Advanced Design System (ADS)

References

[1] Giuseppina Monti, Laura Corchia Giuseppina Monti and Luciano Tarricone, “UHF wearable rectenna on textile material," IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, vol. 61, no. 7, July. 2013

[2] Benton H. Calhoun, Naveen Verma, David D. Wentzlo_, Seong-Hwan Cho, “Design Consideration for Ultra-Low Energy Wireless Microsensor Nodes" IEEE TRANSACTION ON COMPUTERS, vol. 54, no.6, June. 2005