AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

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AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

E SUN YE

UNIVERSITI SAINS MALAYSIA

2017

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AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

by

E SUN YE

Thesis submitted in fulfilment of the requirements for the degree of

Master of Science

April 2017

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ACKNOWLEDGEMENTS

This dissertation is dedicated to everyone in the field of RF energy harvesting who embarks the journey of expanding the collection of knowledge and transcendent pas- sion for continuous improvement of the rectenna designed for RF energy harvesting circuit for WSN application.

First of all, I would like to express my thankfulness to Dr Nor Muzlifah Mahyuddin, my research adviser, for seeing the promise of this research project and achieving research conducted under her watchful eyes. Her guidance and patience throughout this research carried out are much appreciated. Besides, her priceless support and insightful advice and opinion have resulted in the completion of this project.

I would also like to express my acknowledgement to Universiti Sains Malaysia for providing financial support (USM RUI Grant 1001/PELECT/814206) for this research.

My special thanks reached out to all Professors, lectures, technicians and staffs in School of Electric and Electronic Engineering, USM that have lend their helping hands to me when I faced problems. They always provide helpful comments and support during the completion of this project. They also shared ideas by providing inces- sant information on the research techniques and skills. I sincerely appreciate their feed- back and suggestion in providing me a deeper understanding to the project.

Lastly, I offer my regards and blessing to my beloved family especially my parents and Ah Wong who supported me in every aspect during the completion of this project.

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Page Table 1.1 Current Market Availability for Energy Sources 3 Table 2.1 Estimated Power from Various Energy Harvesting Sources 14 Table 2.2 Termination voltage and conversion efficiency 23 Table 2.3 Summary of London RF Survey Measurement 23 Table 2.4 Summary of RF frequency used or researched in previous work 25 Table 2.5 Summary of GSM 900, GSM 1800 and Wi-Fi bandwidths 26

Table 2.6 Antenna Types 31

Table 2.7 S-Parameter (two port network) 36

Table 2.8 Simulated gain and 10-dB return loss fractional bandwidth for 39 folded-dipole single-band antenna

Table 2.9 Summary of the antenna used by previous researchers 47 Table 2.10 Simulation results for output voltage for different stages circuit 57

with different input frequency

Table 2.11 Summary of the diodes used by previous researchers 61 Table 2.12 Summary of the matching techniques used by previous researchers 65

Table 2.13 Summary of all previous work done 66

Table 3.1 Types of diodes and characteristic 71

Table 3.2 Impedance for different stages of 915 MHz Rev A Dickson 76 multiplier

Table 3.3 Lumped elements for each stages of 915 MHz Rev A Dickson 77 multiplier 1

Table 3.4 Lumped elements for each stages of 915 MHz Rev A Dickson 77 multiplier 2

Table 3.5 Impedance for different stages of 915 MHz Rev B Dickson 83 multiplier

Table 3.6 Lumped element for each stage of 915 MHz Rev B Dickson 83 multiplier 1

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Table 3.7 Lumped element for each stage of 915 MHz Rev B Dickson 84 multiplier 2

Table 3.8 Impedance for different stages of 1.8 GHz Rev A Dickson 93 multiplier

Table 3.9 Lumped elements for each stages of 1.8 GHz Rev A Dickson 93 multiplier 1

Table 3.10 Lumped elements for each stages of 1.8 GHz Rev A Dickson 94 multiplier 2

Table 3.11 Impedance of different stages of 1.8 GHz Rev B Dickson 98 multiplier

Table 3.12 Lumped elements for each stages of 1.8 GHz Rev B Dickson 98 multiplier 1

Table 3.13 Lumped elements for each stages of 1.8 GHz Rev B Dickson 98 multiplier 2

Table 3.14 Summary of impedance of different stages of 2.4 GHz Dickson 106 multiplier

Table 3.15 Values of lumped elements for each stages of 2.4 GHz Rev A 106 Dickson multiplier 1

Table 3.16 Values of lumped elements for each stages of 2.4 GHz Rev A 106 Dickson multiplier 2

Table 3.17 Summary of impedance of different stages of 2.4 GHz Rev B 110 Dickson multiplier

Table 3.18 Values of lumped elements for each stages of 2.4 GHz Rev B 111 Dickson multiplier 1

Table 3.19 Values of lumped elements for each stages of 2.4 GHz Rev B 111 Dickson multiplier 2

Table 4.1 Overall parameters for mircrostrip line fed printed wide slot 123 antenna

Table 4.2 Microstrip line fed printed wide slot antenna parameters values 125 for 915 MHz

Table 4.3 Minimum distance requirement for LB-880 far field 130 measurement

Table 4.4 1.8 GHz microstrip line fed printed wide slot antenna parameters 133 Table 4.5 2.4 GHz microstrip line fed printed wide slot antenna parameters 139

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Table 5.1 Output voltage measured by harvesting from a 915 MHz 148 dedicated RF source

Table 5.2 Output voltage measured by harvesting from a 1.8 GHz 148 dedicated RF source

Table 5.3 Output voltage measured by harvesting from a 2.4 GHz 149 dedicated RF source

Table 5.4 Minimum distance requirement for far field measurement 150 Table 5.5 Output voltage measured by harvesting 915 MHz RF signal 152

from Nokia 100 mobile phone

Table 5.6 Output voltage measured by harvesting 1.8 GHz RF signal from 152 Nokia 100 mobile phone

Table 5.7 Output voltage measured by harvesting 2.4 GHz RF signal from 152 TP-Link modem

Table 5.8 Output voltage measured by harvesting ambient RF sources at 156 915 MHz, 1.8 GHz and 2.4 GHz

Table 5.9 Comparison results for 915 MHz rectifier deigned with 157 Kitazawa’s rectifier

Table 5.10 Comparison results for 2.45 GHz rectifier designed with 159 Khansalee’s rectifier

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LIST OF FIGURES

Page

Figure 1.1 Energy Harvesting Systems 2

Figure 1.2 Energy Harvesting Diagram 3

Figure 1.3 Radio Frequency Energy Harvesting Block Diagram 5 Figure 2.1 Potential Source of Energy Harvesting 13 Figure 2.2 Parallel array architectures with switching/summing at the: (a) 16

antenna, (b) output of multiple antennas, (c) output of multiple rectifiers and (d) output of multiple PMMs

Figure 2.3 Effect of multiple antennas on EH circuit’s voltage 18 Figure 2.4 Effect of multiple antennas on EH circuit’s efficiency 18

Figure 2.5 Measured GSM 900 peak power density 20

Figure 2.6 Measured GSM 900 summed power density 20 Figure 2.7 RF power density on GSM 900 in Nanyang Polytechnic, 21

Singapore

Figure 2.8 RF power density on GSM 1800 in Nanyang Polytechnic, 21 Singapore

Figure 2.9 Max allowable receive power vs distance 22 Figure 2.10 Input RF power density measurements 23

Figure 2.11 Two Port Network 36

Figure 2.12 Printed dipole antenna with integrated microstrip via-hole 37 balun, back and front

Figure 2.13 Receiving coil antenna 37

Figure 2.14 Differential microstrip antenna: (a) top view and (b) side view 38 Figure 2.15 50 W folded-dipole antennas next to a British 1 pound coin 38 Figure 2.16 3G copper tape antenna on Perspex 39 Figure 2.17 Three dimensional RFID “Scavenging” antenna using meander 40

line configuration

Figure 2.18 Antenna design with meander lines 41

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Figure 2.19 Dual-linear polarized antenna 41 Figure 2.20 Fabricated rectenna: (a) top view and (b) bottom view 42 Figure 2.21 Proposed antenna design: (a) top view and (b) side view 42

Figure 2.22 Inkjet-printed dipole antenna 43

Figure 2.23 Effect of multiple antennas on EH circuit’s voltage 45 Figure 2.24 Effect of multiple antennas on EH circuit’s efficiency 45

Figure 2.25 Printed hexagonal slot antenna 48

Figure 2.26 Rhombus-like wide slot antenna with an offset microstrip fed line 49 Figure 2.27 Microstrip line fed printed square slot antenna with a rotated slot 49 Figure 2.28 Antenna design with parasitic patch at the ground plane 50 Figure 2.29 Microstrip line fed printed wide slot antennas with: (a) a 51

fork-like tuning stub and (b) a microstrip line tuning stub

Figure 2.30 Microstrip line fed printed wide slot antennas with: (a) semicircle 51 arc-shape slot and a square patch and (b) equilateral triangular

patch

Figure 2.31 Microstrip square split ring slot antenna with fork like tuning stub 52 Figure 2.32 Geometry and dimensions of the proposed microstrip line fed 53

printed fractal slot antenna

Figure 2.33 Geometry and dimensions of the proposed microstrip line fed 53 printed wide slot antenna with a fractal shaped slot

Figure 2.34 Microstrip line fed printed wide slot antenna after two iteration 54 Figure 2.35 Design of the dual band notched slot antenna for WiMAX 55

application

Figure 2.36 Top view of the antenna 55

Figure 2.37 Effect of number of stages on the voltage of energy harvesting 56 circuit

Figure 2.38 Effect of number of stages on the efficiency of energy harvesting 56 circuit

Figure 2.39 Villard multiplier 58

Figure 2.40 Dickson multiplier 60

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Figure 3.1 Overall design block diagram 69

Figure 3.2 Multiplier design block diagram 70

Figure 3.3 Schematic diagram of 915 MHz 2 stages Dickson multiplier 74 Figure 3.4 Schematic diagram of 915 MHz 3 stages Dickson multiplier 74 Figure 3.5 Schematic diagram of 915 MHz 4 stages Dickson multiplier 75 Figure 3.6 Schematic diagram of 915 MHz 5 stages Dickson multiplier 75 Figure 3.7 Schematic diagram of 915 MHz 6 stages Dickson multiplier 75 Figure 3.8 915 MHz 5 Stages Dickson multiplier circuit with 50W term 76 Figure 3.9 915 MHz Rev A 5-Stages Dickson multiplier with matching 78

circuit

Figure 3.10 Vout against RF input for 915 MHz Rev A Dickson multiplier 79 Figure 3.11 Pout against RF input for 915 MHz Rev A Dickson multiplier 79 Figure 3.12 Pout efficiency VS RF input for 915 MHz Rev A Dickson 80

multiplier

Figure 3.13 915 MHz Rev A Dickson multiplier PCB Board 81 Figure 3.14 Schematic diagram of 915 MHz Rev B 2 stages Dickson 81

multiplier

Figure 3.15 Schematic diagram of 915 MHz Rev B 3 stages Dickson 82 multiplier

Figure 3.16 Schematic diagram of 915 MHz Rev B 4 stages Dickson 82 Multiplier

Figure 3.19 915 MHz Rev B 5-Stages Dickson multiplier with matching 84 Circuit

Figure 3.20 Vout VS RF input for 915 MHz Rev B Dickson multiplier 85 Figure 3.21 Pout VS RF input for 915 MHz Rev B Dickson multiplier 85 Figure 3.22 Pout efficiency VS RF input for 915 MHz Rev B Dickson 86

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multiplier

Figure 3.23 915MHz Rev B Dickson multiplier board 86 Figure 3.24 Block diagram for cable loss measurement 87

Figure 3.25 Cable loss measuring set up 88

Figure 3.26 Block diagram for output voltage measurement 88

Figure 3.27 Output voltage measuring set up 88

Figure 3.28 Comparison between simulated and measured Vout for 915 MHz 89 Rev A Dickson multiplier

Figure 3.29 Comparison between simulated and measured Pout efficiency 90 for 915 MHz Rev A Dickson multiplier

Figure 3.30 Comparison between simulated and measured Vout for 915 MHz 90 Rev B Dickson multiplier

Figure 3.31 Comparison between simulated and measured Pout efficiency 91 for 915 MHz Rev B Dickson multiplier

Figure 3.32 Comparison of Vout between 915 MHz Rev A and B 91 Figure 3.33 Comparison of Pout efficiency between 915 MHz Rev A and B 92 Figure 3.34 1.8 GHz Rev A 2-Stages Dickson multiplier with matching circuit 94 Figure 3.35 Vout VS RF input for 1.8 GHz Rev A Dickson multiplier 95 Figure 3.36 Pout VS RF input for 1.8 GHz Rev A Dickson multiplier 96 Figure 3.37 Pout efficiency VS RF input for 1.8 GHz Rev A Dickson 96

Multiplier

Figure 3.38 1.8 GHz Rev A Dickson multiplier PCB Board 97 Figure 3.39 1.8 GHz Rev B 5-Stages Dickson multiplier with matching circuit 99 Figure 3.40 Vout VS RF input for 1.8 GHz Rev B Dickson multiplier 99 Figure 3.41 Pout VS RF input for 1.8 GHz Rev B Dickson multiplier 100 Figure 3.42 Pout efficiency VS RF input for 1.8 GHz Rev B Dickson 101

multiplier

Figure 3.43 1.8 GHz Rev B Dickson multiplier PCB Board 101 Figure 3.44 Comparison between simulated and measured Vout for 1.8 GHz 102

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Rev A Dickson multiplier

Figure 3.45 Comparison between simulated and measured Pout efficiency 103 for 1.8 GHz Rev A Dickson multiplier

Figure 3.46 Comparison between simulated and measured Vout for 1.8 GHz 103 Rev B Dickson multiplier

Figure 3.47 Comparison between simulated and measured Pout efficiency 104 for 1.8 GHz Rev B Dickson multiplier

Figure 3.48 Comparison of Vout between 1.8 GHz Rev A and B 104 Figure 3.49 Comparison of Pout efficiency between 1.8 GHz Rev A and B 105 Figure 3.50 2.4 GHz Rev A 2-Stages Dickson multiplier with matching 107

Circuit

Figure 3.51 Vout VS RF input for 2.4 GHz Dickson multiplier Rev A 108 Figure 3.52 Pout VS RF input for 2.4 GHz Dickson multiplier Rev A 108 Figure 3.53 Pout efficiency VS RF input for 2.4 GHz Dickson multiplier Rev 109

A

Figure 3.54 2.4 GHz Rev A Dickson multiplier PCB Board 109 Figure 3.55 2.4 GHz Rev B 5-Stages Dickson multiplier with matching 111

Circuit

Figure 3.56 Vout VS RF input for 2.4 GHz Rev B Dickson multiplier 112 Figure 3.57 Pout VS RF input for 2.4 GHz Rev B Dickson multiplier 113 Figure 3.58 Pout efficiency VS RF input for 2.4 GHz Rev B Dickson 113

Multiplier

Figure 3.59 2.4 GHz Rev B Dickson multiplier PCB Board 114 Figure 3.60 Comparison between simulated and measured Vout for 2.4 GHz 115

Rev A Dickson multiplier

Figure 3.61 Comparison between simulated and measured Pout efficiency 115 for 2.4 GHz Rev A Dickson multiplier

Figure 3.62 Comparison between simulated and measured Dout for 2.4 GHz 116 Rev B Dickson multiplier

Figure 3.63 Comparison between simulated and measured Pout efficiency for 116 2.4 GHz Rev B Dickson multiplier

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Figure 3.64 Comparison of Vout between 2.4 GHz Rev A and B 117

Figure 3.65 Comparison of Pout efficiency between 2.4 GHz Rev A and B 117

Figure 4.1 Antenna design block diagram 120

Figure 4.2 Top layer of microstrip line fed printed wide slot antenna 122

Figure 4.3 Bottom layer of microstrip line fed printed wide slot antenna 122

Figure 4.4 Calculate port extension coefficient in CST Studio Suite 2014 123

Figure 4.5 Parameter sweep in CST Studio Suite 2014 124

Figure 4.6 915 MHz microstrip line fed printed wide slot antenna 125

parameters at: (a) top layer and (b) bottom layer Figure 4.7 915 MHz microstrip line fed printed wide slot antenna: (a) top 125

layer and (b) bottom layer Figure 4.8 S11 for microstrip line fed printed wide slot antenna at 915 MHz 126 Figure 4.9 915 MHz microstrip line fed printed wide slot antenna: (a) 126

E-field and (b) H-field radiation pattern Figure 4.10 Gain for 915 MHz microstrip line fed printed wide slot antenna 126

Figure 4.11 (a) Top layer and (b) bottom layer of fabricated microstrip line 127

fed printed wide slot antenna at 915 MHz Figure 4.12 S11 return loss and input impedance measurement block diagram 128 Figure 4.13 S11 return loss and input impedance measurement set-up 128

Figure 4.14 S11 results of 915 MHz antenna 128

Figure 4.15 915 MHz antenna input impedance measurement 129

Figure 4.16 Antenna under test set up block diagram 130

Figure 4.17 Antenna under test set up 131

Figure 4.18 915 MHz antenna E-field radiation pattern 131

Figure 4.19 915 MHz antenna H-field radiation pattern 132

Figure 4.20 1.8 GHz microstrip line fed printed wide slot antenna: (a) top 134 layer and (b) bottom layer

Figure 4.21 S11 parameters for 1.8 GHz microstrip line fed printed wide slot 134 antenna

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Figure 4.22 1.8 GHz microstrip line fed printed wide slot antenna: (a) 135

E-field and (b) H-field radiation patterns Figure 4.23 Gain for 1.8 GHz microstrip line fed printed wide slot antenna 135

Figure 4.24 Fabricated 1.8 GHz microstrip line fed printed wide slot antenna: 136 (a) top layer and (b) bottom layer Figure 4.25 S11 results of 1.8 GHz antenna 136

Figure 4.26 1.8 GHz antenna input impedance measurement 137

Figure 4.27 1.8 GHz antenna E-field radiation pattern 138

Figure 4.28 1.8 GHz antenna H-field radiation pattern 138

Figure 4.29 2.4GHz microstrip line fed printed wide slot antenna: (a) top 140

layer and (b) bottom layer Figure 4.30 S11 parameters for 2.4 GHz microstrip line fed printed wide slot 140 Antenna Figure 4.31 2.4 GHz microstrip line fed printed wide slot antenna: (a) 140

E-field and (b) H-field radiation pattern Figure 4.32 Gain for 2.4 GHz microstrip line fed printed wide slot antenna 141

Figure 4.33 Fabricated 2.4 GHz microstrip line fed printed wide slot antenna: 141 (a) top layer and (b) bottom layer Figure 4.34 S11 results of 2.4 GHz antenna 142

Figure 4.35 2.4 GHz antenna input impedance measurement 142

Figure 4.36 2.4 GHz antenna E-field radiation pattern 143

Figure 4.37 2.4 GHz antenna H-field radiation pattern 143

Figure 5.1 Straight 50 W RF adapter SMA male to SMA male connector 146

Figure 5.2 Complete rectenna design 146

Figure 5.3 Dedicated RF energy harvesting measurement block diagram 148

Figure 5.4 Dedicated RF energy harvesting real measurement set up 148

Figure 5.5 Mobile phone RF energy harvesting measurement block diagram 151

Figure 5.6 Mobile RF energy harvesting real measurement set up 151

Figure 5.7 Modem RF energy harvesting real measurement set up 151

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Figure 5.8 RF signal from Nokia 100 153

Figure 5.9 Ambient RF energy harvesting measurement block diagram 155

Figure 5.10 Ambient RF energy harvesting measurement block diagram 155

Figure 5.11 Ambient RF energy harvesting real measurement set up 156

Figure 5.12 Comparison results for 915 MHz Rev B rectifier designed with 158

Deep Patel’s rectifier Figure F.1 915MHz Rev A Dickson multiplier layout 230

Figure F.2 915MHz Rev B Dickson multiplier layout 230

Figure F.3 1.8GHz Rev A Dickson multiplier layout 230

Figure F.4 1.8GHz Rev B Dickson multiplier layout 231

Figure F.5 2.4GHz Rev A Dickson multiplier layout 231

Figure F.6 2.4GHz Rev B Dickson multiplier layout 231

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LIST OF ABBREVIATIONS

RF radio frequency

WSN wireless sensor network IPS Institut Pengajian Siswazah USM Universiti Sains Malaysia WLAN wireless local area network VSWR voltage standing wave ratio

VS versus

etc et cetera

TV television

DC direct current

AC alternating current

PCB printed circuit board ADS Advanced Design System

GSM Global System for Mobile Communications DTV digital television

3G third generation

FCC Federal Communication Commission

MCMC Malaysian Communications and Multimedia Commission

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REKA BENTUK REKTENA YANG DITAMBAHBAIK BAGI PENUAIAN TENAGA RF

ABSTRAK

Pada masa ini, penuaian tenaga frekuensi radio (RF) telah menjadi semakin popular dalam teknologi hijau kerana penambahan daripada stesen pangkalan televisyen, stesen pangkalan telefon mudah alih, Wi-Fi, Bluetooth dan lain-lain. Banyak kajian telah dilakukan ke atas penuaian tenaga RF. Walau bagaimanapun, tenaga RF yang terdapat di sekitar masih terlalu kecil dan kecekapan penukaran di bahagian pengganda adalah sangat rendah. Oleh itu, dalam kajian ini, reka bentuk rektena untuk litar penuaian tenaga RF dalam aplikasi penderia untuk menuai tenaga RF daripada sumber berdedikasi dan ambien telah direka dan dibentangkan. Kajian ini membentangkan tiga reka bentuk rektena yang memberi tumpuan kepada tiga frekuensi yang berbeza iaitu GSM 900, GSM 1800 dan band Wi-Fi kerana kewujudan isyarat tersebut di sekeliling kita. Kajian ini dijalankan dalam beberapa peringkat yang melibatkan reka bentuk litar pengganda, reka bentuk antena, ujian dan pengukuran bagi setiap bahagian, kombinasi pengganda dan antena untuk membentuk rektena serta ujian dan pengukuran untuk rektena. Rektena yang beroperasi pada 915 MHz dapat mencapai voltan pengeluaran sebanyak 0.115 V apabila menuai isyarat RF dari Nokia 100 pada jarak 30 cm. 0.067 V boleh diukur apabila rektena 915 MHz menuai tenaga RF sekitar USM. Rektena yang beroperasi pada 1.8 GHz dapat mencapai voltan pengeluaran sebanyak 0.273 V apabila ia menuai tenaga RF daripada Nokia 100 pada jarak 30 cm. Apabila rektena yang menuai tenaga RF daripada sekeliling, 0.042 V voltan pengeluaran boleh dicapai.

Voltan keluaran 0.214 V boleh dicapai apabila rektena 2.4 GHz menuai tenaga RF dari modem router TP-Link dengan jarak 50 cm. 0.037 V voltan pengeluaran boleh

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diperolehi apabila rektena 2.4 GHz menuai tenaga RF sekeliling. Rektena yang direka menunjukkan prestasi yang baik dan menunjukkan peningkatan daripada kajian sebelumnya tetapi masih mempunyai ruang untuk diperbaiki pada masa akan datang.

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AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

ABSTRACT

Nowadays, Radio Frequency (RF) energy harvesting has become increasingly popular in green technology due to the high rise of the television base stations, mobile phone base stations, Wi-Fi, Bluetooth and others. Many researches have been done on harvesting the RF energy. However, the RF energy available around is still too small and the conversion efficiency at the multiplier part is very low. Thus in this research, an improved rectenna design for RF energy harvesting circuit for WSN application has been designed to harvest the RF energy from a dedicated and ambient sources is presented. This research presents three rectenna design which focusing at three different frequencies which are GSM 900, GSM 1800 and Wi-Fi band due to the availability of those signal around us. This research is progressed in few stages involving designs of multiplier circuit, designs of antenna, test and measurement of each part, combination of multiplier and antenna to form rectenna and rectenna test and measurement. Rectenna operating at 915 MHz is able to achieve an output voltage of 0.115 V when harvesting RF signal from Nokia 100 at a distance of 30 cm.

0.067 V can be measured when 915 MHz rectenna harvest RF energy around USM.

Rectenna operating at 1.8 GHz able to achieve an output voltage of 0.273 V when it harvest the RF energy from Nokia 100 at a distance of 30 cm. When the rectenna harvest the ambient RF Energy, 0.042 V of output voltage can be measured.

Additionally output voltage of 0.214 V can be achieved when the 2.4 GHz rectenna harvest RF energy from a TP-Link modem router with a distance of 50 cm. A 0.037 V of output voltage can be obtained when 2.4 GHz rectenna is harvesting ambient RF

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energy. The designed rectenna are able to perform well under three conditions or environments. Subsequently they show significant improvements over other related works and in turns have space for further improvement in the future.

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1

CHAPTER ONE INTRODUCTION

1.1 Significant of Project

Advance developments in sensing technology or mobile handheld devices involving

microprocessor and miniaturized radio transceivers have rapidly increased the development of smart structures and machines to be realized. The dream for the future

is a universal smart wireless sensor network (WSN) which can autonomously operate and able to accommodate structural or systematic health monitoring, embedded test and evaluation and condition based maintenance of public properties

such as bridges, trains and aircraft. WSN is able to alert users or systems of any in-coming disasters or even eliminating the unnecessary scheduled maintenance, thus

reducing the cost of human resources. This in evidently improves the safety and reliability of public transportation, industrial manufacturing and military system infrastructure while greatly reduce the maintenance cost.

However in order for the sensor networks to be fully autonomous, there must be a need to eliminate the use of battery and provide alternatives that can both harvest and store the energy continuously; self-sustaining the whole network system. Without the need for battery replacement, there will be no service disruption, thus the maintenance cost will be low. Subsequently, energy harvesting technology has a high potential in replacing batteries or to prolong the life of rechargeable batteries for low power electronic devices.

AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

E SUN YE

UNIVERSITI SAINS MALAYSIA

2017

ACKNOWLEDGEMENTS

TABLE OF CONTENTS

LIST OF FIGURES

LIST OF ABBREVIATIONS

REKA BENTUK REKTENA YANG DITAMBAHBAIK BAGI PENUAIAN TENAGA RF

ABSTRAK

AN IMPROVED RECTENNA DESIGN FOR RF ENERGY HARVESTING

ABSTRACT

CHAPTER ONE INTRODUCTION