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

Project information

Introduction

Wearable electronic devices are in growing number of uses. Recent years, a number of wearable low power sensors are used in the area of health-care [1] such as electrocardiogram (ECG) and electroencephalography (EEG). These sensors are low energy required which means that several μW [2] is sufficient enough to drive these kinds of sensors. Some devices require longer lifetime working under some circumstances [2], so having a renewable energy source instead of using battery source becomes necessary.

In this project, the rectenna is designed in two parts which is shown on Figure 1. The first part is a dual band antenna which is able to collect ambient RF energy with frequency of GSM 900 and GSM 1800. The second part is a rectifier which is used to convert RF energy to DC energy in order to make the rectenna be able to provide DC power. A schematic of the design concept is illustrated below.

Concept Schematic

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