Master of Science in Electronic Engineering

Faculty of Electronic and Computer Engineering

INVERSE PHI SLOTTED ANTENNA DESIGN

FOR RFID APPLICATION

Norazura Binti Md Nor

2014

INVERSE PHI SLOTTED ANTENNA DESIGN FOR RFID APPLICATION

NORAZURA BINTI MD NOR

A thesis submitted

in fulfillment of the requirements for the degree of Master of Science in Electronic Engineering

Faculty of Electronic and Computer Engineering

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

2014

i

DECLARATION

I declare that this thesis entitle “Inverse Phi Slotted Antenna design for RFID application”

is the result of my own research except as cited in the references. The thesis has not been

accepted for any degree and is not concurrently submitted in candidature of any other

degree.

Signature :……………. .....................................................

Name :……………………… ......................................

Date :…………………….. ........................................

NORAZURA BINTI MD NOR

22 NOVEMBER 2013

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APPROVAL

I hereby declare that I have read this report and in my opinion this report is sufficient in

terms of scope and quality for the award of Master of Science in Electronic Engineering

Signature :……………. .....................................................

Supervisor Name : ……………………… .....................................

Date : …………………….. .......................................

DATO' PROF DR MOHAMAD KADIM BIN SUAIDI

24 NOVEMBER 2013

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DEDICATION

To my supervisor Dato’ Prof Dr Mohamad Kadim Suaidi;

To my mentor Imran bin Mohd Ibrahim who teaches me from zero;

To my husband Mohd Izwan bin Abu Bakar who always behind me,

To my daughter Irdeena Nurzara binti Mohd Izwan,

and my family who always support me

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ABSTRACT

In RFID application, the antennas are the most paramount components required to

engender a communication link between tag and reader. Dual band or multiple band

antennas is designed to prevent excessive radiation effects due to the use of various sets of

reader antenna in a system. Dual-band antenna is designed to operate at a frequency of

900MHz and 2.45GHz to meet the needs of RFID applications. Accordingly, these

antennas help reduce the amount of RFID reader antennas in the RFID system. Planar

monopole antennas are the most suited for indoor and mobile applications because of their

low profile, light weight and omnidirectional characteristics. With the omnidirectional

radiation pattern characteristic, this antenna will suit for portable RFID reader application.

The major consideration for antenna design for handheld/ portable reader RFID reader

applications is the compact size, while the antenna gain and bandwidth are not critical

issues. Planar monopole can be designed in a variety of shapes in order to obtain enhanced

bandwidth, dual band and ultra-wideband operation. Inverse Phi Slotted Antenna has been

introducing based on planar antenna concept and able to provide a dual-band bandwidth

for RFID application. This thesis provides a detailed study of the design of Inverse Phi

Slotted Antenna to facilitate linear polarized and dual band operation. The design

parameters of the antenna have been calculated utilizing the transmission line model. The

effect of antenna dimensions on the performance of antennas has been discussed. This

antenna is designed to use the technique of reactive load for the operation of dual- band

RFID reader. The center frequencies of these bands are controlled by the electrical length

of slots. A moderate gain has successfully achieved.

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ABSTRAK

Dalam aplikasi RFID, antena merupakan komponen penting yang diperlukan untuk

mewujudkan hubungan komunikasi antara tag dan pembaca. Dwi jalur atau pelbagai jalur

antena direka untuk mencegah kesan radiasi ekoran penggunaan pelbagai jenis pembaca

RFID didalam sebuah sistem. Bagi memenuhi keperluan aplikasi RFID masa kini, dwi

jalur antena ini telah direka untuk beroperasi pada frekuensi 900MHz dan 2.45GHz.

Sehubungan itu, antena ini membantu mengurangkan jumlah penggunaan set antena

dalam sistem RFID. Antena Satah Kutub Tunggal begitu sesuai digunakan untuk aplikasi

dalaman dan bersifat mudah alih kerana ciri-cirinya yang rata, ringan dan memiliki corak

sinaran serata tumpuan. Dengan ciri-ciri ini, antena ini sesuai untuk aplikasi RFID

pembaca mudah alih. Pertimbangan utama bagi reka bentuk antena untuk pembaca RFID

mudah alih adalah bersaiz padat, manakala gandaan antena dan jalur lebar tidak begitu

penting. Antena Satah Kutub Tunggal Planar boleh direka dalam pelbagai bentuk untuk

mendapatkan jalur lebar yang dipertingkatkan, dwi-jalur dan operasi jalur ultra-lebar.

Inverse Phi Slotted Antenna direka berdasarkan konsep antena planar dan ia mampu

menghasilkan dwi jalur lebar untuk aplikasi RFID. Tesis ini menyediakan kajian terperinci

reka bentuk Inverse Phi Slotted Antenna untuk menghasilkan operasi jalur dwi frekuensi

dan berpengutuban sesatah. Parameter rekabentuk antena telah dikira dengan

menggunakan teknik talian penghantaran. Kesan saiz antena terhadap prestasi turut

dibincangkan. Antena ini direka dengan menggunakan teknik beban reaktif untuk operasi

pembaca RFID dwi-jalur. Pusat jalur frekuensi ini dikawal oleh saiz slot. Gandaan

sederhana telah berjaya dicapai.

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ACKNOWLEDGEMENTS

In the name of Allah, Most Gracious, Most Merciful. Praise be to Allah, the Cherisher and

Sustainer of the Worlds. With His permission I have completed this thesis and hopefully

this thesis will benefit the development of the Ummah all over the world.

Firstly I would like to give my heartiest gratitude to the Centre for Research and

Innovation Management, who has given support me and my research team in providing the

facilities and equipment for us to initiate our work. I would also like to thank my project

supervisor who has spent a great deal of their precious time to lead this task. Your advice,

guidance, kindness and support will always be my aspiration for the future. They have

given me an inspiration to excel in the future.

Next, I would like to thank my colleagues and those who involve in this project

which through discussion and exchanging ideas in this project which benefit all. Their

support and friendship will always be treasured.

Lastly, I would also like to give my sincerest gratitude to my husband and family for their

full support in this undertaking. Their support and patience is a motivation for my work.

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TABLE OF CONTENTS

PAGE

DECLARATION

APPROVAL

DEDICATION

ABSTRACT i

ABSTRAK ii

ACKNOWLEDGEMENTS iii

TABLE OF CONTENTS iv

LIST OF TABLES vi

LIST OF FIGURES vii

LIST OF APPENDICES x

LIST OF ABBREVIATION xi

LIST OF PUBLICATIONS xiii

CHAPTER

1. INTRODUCTION 1.0 Research Background 1

1.1 Problem Statement 1

1.2 Objective 3

1.3 Contribution of Project 3

1.4 Scope of project 3

1.5 Organization of thesis 4

2. LITERATURE REVIEW ON RFID TECHNOLOGY

2.0 Introduction 6

2.1 RFID Research Background 6

2.2 RFID Technology 10

2.2.1 Component RFID system 11

2.2.2 RFID Frequency Band 15

2.3 RFID standard regulation and spectrum allocations 17

2.4 Antenna for RFID system 18

2.4.1 Antenna for RFID Reader 18

2.5 Conventional Techniques for Dual Band Microstrip Antennas 25

2.5.1 Use of Orthogonal Mode 26

2.5.2 Use of Multiple Patches 26

2.5.3 Use of Reactive Loading to Patch 27

2.6 Summary 28

3. RESEARCH METHODOLOGY 29

3.0 Introduction 29

3.1 Project Methodology 29

3.1.1 Flowchart Antenna Design Methodology 30

3.2 Inverse Phi Slotted Antenna Design Procedure 31

3.2.1 Design parameter 31

3.2.2 Substrate Selection 32

3.2.3 CST Micro Wave Studio 32

v

3.2.4 Dimension determination 33

3.2.5 Parametric study 35

3.3 Final design Inverse Phi Slotted Antenna 45

3.4 Fabrication Inverse Phi Slotted Antenna 48

3.5 Measurement of IPSA Antenna 51

3.5.1 Input Return Loss Measurement 51

3.5.2 Gain Measurement 53

3.5.3 Radiation Pattern Measurement 53

3.6 Validating with RFID system 57

3.7 Summary 60

4. RESULTS AND DISCUSSION 61

4.0 Introduction 61

4.1 Simulated and measured return loss 61

4.2 Simulation and measured gain 61

4.2.1 Gain response 63

4.2.2 Simulated and measurement radiation pattern 65

4.2.3 Validation measurement result 68

4.3 Summary 68

5. SUMMARY, CONCLUSION AND RECOMMENDATION

FOR FUTURE RESEARCH 69

5.0 Conclusion 69

5.1 Achievement of research 69

5.2 Recommendation 70

REFERENCES 71

APPENDICES 81

vi

LIST OF TABLES

TABLE TITLE PAGE

2.1 Radio regulations on UHF RFID in different regions 18

2.2 List antenna development on RFID reader 19

3.1 Design parameter specification 31

3.2 FR4 properties 32

3.3 Return loss comparison for various slot 39

3.4 Bandwidth comparison for various slot 40

4.2 Simulated and measured bandwidth IPSA 62

4.1 Simulated and measured return loss IPSA 62

4.2 Simulated and measured bandwidth IPSA 63

4.3 Gain comparison 65

4.4 Measured reading distance 68

vii

LIST OF FIGURES

FIGURE TITLE PAGE

2.1 Book management system using the handheld RFID reader 11

2.2 Basic components RFID system 12

2.3 Passive tag 13

2.4 Handheld and fixed RFID reader 14

2.5 Radio frequency spectrum 15

3.1 Flowchart of RFID Antenna design methodology 30

3.2 Rectangular patch antenna 33

3.3 Rectangular patch antenna with partial ground plane 35

3.4 Rectangular patch with step 36

3.5 Field distribution in slot 37

3.6 Rectangular patch with step and slot 38

3.7 Effect on insertion slot to the return loss of prototype 38

3.8 The return loss versus frequency for different value of length

Vslot

40

3.9 The return loss versus frequency for difference value of Ds. 41

3.10 The variation in distance of Ds1 value 42

3.11 Effect on the variation in distance of Ds1 value to the return

loss

43

3.12 IPSA without step 43

viii

3.13 Effect of step to return loss of IPSA 44

3.14 IPSA with full ground 45

3.15 Structure of final IPSA (a) front view (b) back view 45

3.16 Simulated surface current distributions of the antenna (a)

without and (b) with the single slot (c) with 2 slots at

frequency 910MHz.

47

3.17 Simulated surface current distributions of the antenna with 3

slot at frequency (a) 910MHz and (b) 2450MHz.

47

3.18 Printed laser film with final IPSA layout 48

3.19 UV Process 49

3.20 Process developer 49

3.21 Etching process 50

3.22 Prototype of inverse phi slotted antenna (a) front view (b)

back view

50

3.23 Agilent Network analyzer 52

3.24 Calibration tools 52

3.25 Block diagram of radiation pattern measurement using RF

Analyzer.

54

3.26 Radiation pattern measurement 55

3.27 Rohde & Schwarz dipole antenna 55

3.28 Agilent horn antenna 56

3.29 Commercialized RFID system 57

3.30 Complete RFID system with Inverse Phi Slotted Antenna 58

3.31 RFID tag attaches to the product 58

ix

3.32 Inverse phi antenna detection range 59

3.33 Output RFID system 60

4.1 Measured and simulated return loss for IPSA 61

4.2 Gain response vs return loss at frequency 910MHz 64

4.3 Gain response vs return loss at frequency 2.45GHz 64

4.4 Simulated and measured result E-plane radiation pattern of

910MHz.

65

4.5 Simulated and measured result H-plane radiation pattern of

910MHz.

66

4.6 Simulated and measured result (a) E-plane and (b) H-plane

radiation pattern of 2.45GHz.

67

x

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Patent 81

B1 Signal Generator 700MHz~8GHz 83

B2 PSA Spectrum Analyzer 83

B3 Antenna Training System 83

B4 Antenna Rotating Positioner 84

C Agilent FieldFox RF Analyzer N9912A 85

D Commercialized 800~900MHz Wall/Mast Mount

Omnidirectional Antenna 87

E Transmitter and receiver module 88

xi

LIST OF ABBREVIATION

AC Alternating current

AF Antenna factor

AM Amplitude modulation

AR Axial ratio

AUT Antenna under test

BER Bit error rate

CAD Computer-aided design

CDF Cumulative distribution function

CEM Computational electromagnetics

CP Circular polarization

CPW Coplanar waveguide

DC Direct current

DCS Digital cellular system

DRA Dielectric resonant antenna

DUT Device under test

EAS Electronic article surveillance

EIRP Effective isotropic radiated power

EM Electromagnetic

EMC Electromagnetic compatibility

ERP Effective radiated power

xii

FCC Federal communication

FDTD Finite-difference time domain

FEM Finite element method

FNBW First null beamwidth

GPS Global positioning system

GSM Global system for mobile communications

HF High frequency

HPBW Half-power beamwidth

IEEE International

IFF Interrogate friend of foe

IPA Inverse phi antenna

ISO International standard organization

LF Low frequency

RF Radio frequency

RFID Radio frequency identification

TEM Transverse electromagnetic (mode/field)

TX Transmit

UHF Ultra high frequency

UWB Ultra wideband

VHF Very high frequency

VSWR Voltage standing wave ratio

WLAN Wireless local area network

WWII World war 2

xiii

LIST OF PUBLICATIONS

The research papers produced and published during the course of this research are

as follows:

1. Nor, M.N., Ibrahim, I.M., Suaidi, M.K., Abu, M., 2011. Inverse Phi Antenna for

RFID Application. Journal of Telecommunication, Electronic and Computer

Engineering (JTEC), vol.3 no 1. ISSN NO: 2180-1843

2. Nor, M.N., Ibrahim, I.M., Suaidi, M.K., Abu, M., 2011. A Study on Dual-Band

Slotted Planar Antenna Design for RFID Application. 4th

International Symposium

on Broadband Communications (ISBC 2010), Equatorial Hotel, Melaka, Malaysia,

11-14 July 2010.

3. Nor, M.N., Ibrahim, I.M., Suaidi, M.K., Abu, M., 2011. Dual-Band Slotted Planar

Antenna for RFID Application. 4th

International Conference on Postgraduate

Education (ICPE-4), Cititel Mid Valley, Kuala Lumpur, Malaysia, 26-28

November, 2010.

1

CHAPTER 1

INTRODUCTION

1.0 Research Background

Springing up with the demand for wireless communications has changed the life

style of today's society. These developments urge to increase capacity broadband antennas

for communication systems. This is because the antenna is a very important component of

the communication system, such as the Radio Frequency Identification (RFID) systems

application. The reader antenna plays a significant role in the communication between

reader and tag. Without a suitable antenna design, signal generated by the Radio Frequency

(RF) system will not be rendered and no signal can be detected at the receiver (RFID Tag)

(Finkenzeller, K., 2003).

1.1 Problem Statement

More recently, an Ultra-High Frequency (UHF) band passive RFID system has

attracted much attention (Finkenzeller, K., 2003). It is generally accepted that the UHF

RFID systems can revolutionize various commercial applications such as supply chain

management (Kim, D.Y., 2008). Several major supply chain companies like Wal-Mart and

Tesco plans to enforce the use of UHF RFID in their supply chain, which operates in the

860-960MHz band. (Leong, K. S., 2006). These developments have a huge impact if

dozens or hundreds of reader antenna began operating in close proximity to each other. As

a result, it can cause serious disorders.

2

The communication between readers and tags created by irradiation tags with RF

energy from the reader and recovers data from RF radiation reflected back from the tag to

the reader. In order to ward off the influence of the other existing radio system, many

countries have earned the same regulation limits the maximum power output of the RFID

system. Under the restrictions reader output power, distance reading RFID system is

related to the size of the reader antenna and the magnetic field emitted by the reader

antenna. Reader antenna design is one element that contributes to the complexity as the

reader antenna can vary in size and dimensions, depending on the specific application

requirements. As a channel for data communication between the chip-based RFID tags and

readers, antenna design and location are important in determining the zone coverage, and

reliability of data communication networks.

Many types of antennas have been designed to meet their needs. Most of UHF

RFID reader is kind of planar antennas. Planar antennas have larger variations than any

type of antenna. Due to its advantages such as low profile and ability to use printed circuit

assembly technology, antenna manufacturers and researchers can come out with a novel

antenna design in-house will reduce development costs. Planar antennas are also relatively

inexpensive to produce and are designed for the physical geometry of a simple 2-

dimensional. They usually work at UHF and higher frequency as the antenna size is

directly related to the wavelength of the resonant frequency (Sweeney, P.J., 2005).

In the ultra-wideband planar antenna, it has been found that the presence of V-slot

and U-slot introduce the band position, and this has been used to reduce interference.

However, for the microstrip patch antenna, V-slots are used primarily to increase

bandwidth and instead of introducing the band position (Lee, K. F., 2011). In this study,

the structure of inverse phi slots will be utilized for the development of dual-band

frequency. Dual band antenna design using features of simple structure is a very

3

challenging task. In this thesis, the proposed antenna is known as Inverse Phi Slotted

Antenna (IPSA).

1.2 Objective

The primary aim of this work is to design, simulate and fabricate antenna for RFID

Reader application. Antenna design must fulfill the following criteria;

1. To design an antenna that can operate in two frequency bands in the frequency

of 900MHz and 2.45GHz with a simple structure.

2. To analyze the performance of this antenna

3. To compare the performance of the IPSA antenna with real RFID measurement

system.

1.3 Contribution of Project

From the research work, an IPSA has managed to reduce the interference by

minimizing the set of RFID reader antennas. Other contributions from this study, the IPSA

can operate a dual frequency band. The IPSA is compact, simple to design and easy to

fabricate. This antenna can also be applied to the multiple side coverage area of the

advantages omni directional characteristics.

1.4 Scope of project

This study focuses to the development of IPSA for RFID reader application that

meets the satisfying performance of the RFID system. The antenna was designed to operate

at a dual-band frequency of 860-960MHz and 2.45GHz. Firstly, in this study concept of

communication between RFID reader and tag has been explored. Secondly, the type of

antenna commonly used for RFID reader for the 860MHz-960MHz antenna and 2.45GHz

4

antenna are explored and compared. Thru the selected design parameter, antenna was

designed to satisfy the objective of the research. Performance of antenna design will

investigates by performing a parametric study using CST software.

1.5 Organization of thesis

This thesis consists of five chapters that will explain all the work carried out during

the research project progresses. The organization of the thesis is generally described as

follows:

This chapter summarizes the background to the issues related to the application of

RFID systems. Through the issues arising problems, the best solution will be proposed in

the research objective. The important contribution of this study will be explained more

clearly. Followed by the main scope of this study that relate to the objectives of the study.

The second chapter focused on the literature review on RFID technology. Where RFID

research background will be explored so that the reader more clearly about the early history

of the presence of RFID technology. The author also explains about basic introduction to

RFID technology including its key components, and standard operating frequency

regulation involved in the use of RFID systems. This chapter also summarizes the early

studies of RFID reader antenna with basic techniques to make a dual - band frequency.

Chapter three focuses on the development of antenna design methods. Starting with

the selection of design parameters, the necessary software to simulate the design, the

equations needed to design an antenna, this chapter also notes the procedures to be

considered further. The results of measurement and analysis will be presented in chapter

four for comparing the performance of an antenna designed by the design parameters.

Parameter to be compared is the return loss, radiation patterns and antenna gain. The final

chapter will highlight the overall research conclusions and future work recommendations

5

to improve the antenna design. These studies are summarized in this thesis with aims to

share knowledge and future upgrades can be established by other researchers in the future.

6

CHAPTER 2

2 LITERATURE REVIEW ON RFID TECHNOLOGY

2.0 Introduction

Chapter 2 will discuss the history of the beginning of RFID and RFID key

components. Then, brief introduction of operating frequency, types of RFID applications

was included in this chapter. In addition, this chapter also presents a brief initial study

related to the reader antenna. Conventional techniques to get a dual band will be drawn in

the final section.

2.1 RFID Research Background

The last half of the 19th century witnessed many advances in our understanding of

electromagnetic energy. By the turn of that century, the works of Faraday, Maxwell, Hertz,

and others had yielded a complete set of laws describing its nature. Beginning in 1896,

Marconi, Alexanderson, Baird, Watson, and many others sought to apply these laws in

radio communications and radar. The work done in this era forms the building blocks upon

which many technologies have been built, including RFID. World War 2 (WWII) brought

about more advancement in radio frequency communications and radar. Following the war,

scientists and engineers continued their research in these areas and increasingly sought

civilian uses for it. The idea of RFID of objects and remote control of devices was

first introduced in late 1948 (Stockman, H., 1948). In October of 1948, Harry Stockman

published a paper titled “Communications by Means of Reflected Power,” in the