Design Microstrip Square Patch Array Antenna At 2.5GHz By Using Graphene For WiMAX Application.
i
DESIGN MICROSTRIP SQUARE PATCH ARRAY ANTENNA AT 2.5GHz BY
USING GRAPHENE FOR WiMAX APPLICATION
YULLY ERWANTI BINTI MASRUKIN
This Report Is Submitted In Partial Fulfillment of Requirement for the Bachelor
Degree of Electronic Engineering (Wireless Communication)
Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer
Universiti Teknikal Malaysia Melaka
JUNE 2015
ii
iii
iv
v
Special dedication to my late father, Masrukin Bin Ideris, my lovely mother, Rabi’ah
Binti Hussein and my family.
vi
ACKNOWLEDGEMENT
Alhamdulilah with His blessing and the strengths, I am successfully completed
my project and thesis. First of all, I would like to my special gratitude to my supervisor,
En Azman Bin Awang Teh for his guidance, support and supervision to encounter the
problem in completing my project and thesis.
I also would like to thank PM Dr Zahriladha Bin Zakaria and Engr. Norbayah
Binti Yusop as my panel for PSM I and PSM II for their valuable comment in
improving my project. I am also be thankful to my family for their moral support and
encouragement.
Last but not least, I would to thank to all my friends for their help, knowledge
and assistance to accomplish my project and thesis. To those who indirectly
contributed to this thesis, your kindly means a lot to me.
vii
ABSTRACT
In recent time, there is a very large request by the consumer for integrated wireless
digital applications. Antenna that preferred in this demand should be low profile, light
weight and broad bandwidth. Microstrip antenna be selected to fulfil these
requirement. Due to the restraint of microstrip antenna such that low gain, narrow
bandwidth with low efficiency, constructing many patch in array configuration is
preferred to overwhelm the disadvantages. Nowadays, graphene has attain a great
demand from the device community. In this project, graphene is an element that
preferred in replacing the copper as patch material to improve the performance of
antenna. This is because of its advantages for instance light weight, strong, transparent
and good conductor of heat and electricity. This thesis presents the design of microstrip
square patch antenna with resonant frequency at 2.5GHz for WiMAX application. The
proposed design antennas are single patch and patch array of four by N (4xN) antenna,
which N=1, 2, 3 and 4 for two types of patch materials such as graphene and copper.
Two thickness of graphene been used in this design such that 0.035mm and 0.35nm.
The array of 4xN patch array microstrip square antenna with microstrip line feeding
based on quarter wave impedance matching technique was designed and simulated by
using Computer Simulation Studio 2011 (CST) software. The performance for the
single patch and patch array microstrip antenna for two types of patch materials;
graphene and copper are compared in terms of return loss, gain and directivity. From
the simulation, the highest return loss obtained is -27.16dB, while gain is 6.4520dB
and directivity is 13.180dB. From the overall results, 4x4 patch array antenna of
graphene with the thickness of 0.35nm gives the best performance among the others
in terms of return loss, gain and directivity. In this project, prove that graphene gives
an improvement in the performance of antenna due to its high conductivity.
viii
ABSTRAK
Kebelakangan ini, terdapat banyak permintaan oleh pengguna terhadap aplikasi digital
tanpa wayar. Antena yang dipilih dalam permintaan ini seharusnya berprofil rendah,
ringan dan mempunyai lebar jalur yang besar. Antenna mikrostrip dipilih untuk
memenuhi keperluan ini. Disebabkan kekangan antena mikrostrip seperti gandaan
yang rendah, lebar jalur sempit dengan kecekapan yang rendah, membina banyak
tampal dalam bentuk konfigurasi tatasusunan telah dipilih untuk mengatasi
keburukannya. Pada masa kini, graphene telah mendapat permintaan tinggi daripada
komuniti peranti. Dalam projek ini, graphene adalah unsur yang dipilih untuk
menggantikan tembaga sebagai bahan tampal untuk meningkatkan prestasi antenna.
Ini kerana kelebihannya misalnya seperti ringan, kuat, telus dan konduktor haba dan
elektrik yang baik. Thesis ini membentangkan reka bentuk tampal mikrostrip segi
empat sama dengan frekuensi salunan pada 2.5GHz untuk aplikasi WiMAX.
Cadangan reka bentuk antena adalah satu tampal dan tatasusunan tampal bagi empat
oleh N (4xN) antenna yang N=1, 2, 3 dan 4 untuk dua jenis bahan tampal seperti
graphene dan tembaga. Dua ketebalan graphene telah digunakan dalam reka bentuk ini
iaitu 0.035mm dan 0.35nm. Tatasusunan daripada microstrip tampal segi empat sama
4xN dengan talian suap berasaskan teknik suku gelombang padanan galangan telah
direka dan disimulasi dengan menggunakan perisian Computer Simulation Studio
2011 (CST). Prestasi untuk satu tampal dan tatasusunan antena mickrostrip tampal
untuk dua jenis bahan tampal; graphene dan tembaga dibandingkan dari segi
kehilangan balikan, gandaan dan “direktiviti”. Daripada simulasi, kehilangan balikan
yang paling tinggi dicapai adalah -27.16dB, manakala gandaan adalah 6.4520dB dan
“direktiviti” adalah 13.180dB. Daripada hasil kesuluruhan, 4x4 tatasusunan tampal
daripada graphene dengan ketebalan 0.35nm memberi prestasi yang terbaik antara
yang lain dari segi kehilangan balikan, gandaan dan “direktiviti”. Dalam projek ini
telah membuktikan bahawa graphene telah memberi peningkatan dalam prestasi
antenna disebabkan konduktivitinya yang tinggi.
ix
TABLE OF CONTENT
CHAPTER
1
CONTENT
PAGE
PROJECT TITLE
i
DECLARATION
iii
DEDICATION
v
ACKNOWLEDGEMENT
vi
ABSTRACT
vii
ABSTRAK
viii
TABLE OF CONTENT
ix
LIST OF TABLES
xiii
LIST OF FIGURES
xiv
INTRODUCTION
1
1.1 PROJECT BACKGROUND
1.1.1 Graphene
2
1.2 PROBLEM STATEMENT
4
1.3 OBJECTIVES
4
1.4 PROJECT SCOPES
5
1.5 BRIEFLY EXPLANATION ON
5
3
METHODOLOGY
1.6 THESIS PLAN
5
x
2
LITERATURE REVIEW
2.1 ANTENNA DEFINITION
7
2.2 MICROSTRIP PATCH
8
2.2.1 Rectangular Patch
2.3 ARRAY ANTENNAS
10
2.4 FEED NETWORKS
12
2.5 QUARTER WAVELENGTH TRANSFORMER
13
2.6 PARAMETERS OF ANTENNAS
13
2.6.1 Radiation Pattern
14
2.6.2 Directivity
14
2.6.3 Bandwidth
15
2.6.4 Polarization
15
2.6.5 Antenna Efficiency
16
2.6.6 Gain
16
2.6.7 VSWR
16
17
2.7 GRAPHENE
3
10
METHODOLOGY
3.1 OVERVIEW OF METHODOLOGY
19
3.2 SUBSTRATE MATERIAL
22
3.3 DESIGNING ANTENNA
23
3.3.1 Single Microstrip Patch Design
23
3.3.1.1 Calculation of Patch Design
24
3.3.1.2 Calculation of Impedance for
25
Quarter-Wave Transformer
xi
26
28
28
28
31
32
34
34
35
37
39
39
39
40
42
44
44
45
47
49
49
50
52
54
xii
3.3.2 Microstrip Patch Array Antenna Design
3.3.2.1 Patch Calculation
3.3.2.2 Calculation of Impedance for
Quarter-Wave Transformer
3.3.3 Design of 4xN Patch Array Antenna
3.3.4 Introduction to CST 2011 Studio Suite Software
3.3.5 Flowchart
4
RESULTS AND DISCUSSION
4.1 Single Patch Antenna
4.1.1 Return Loss
4.1.2 Gain
4.1.3 Directivity
4.2 Patch Array Antenna
4.2.1 4x1 Patch Array antenna
4.2.1.1 Return Loss
4.2.1.2 Gain
4.2.1.3 Directivity
4.2.2 4x2 Patch Array antenna
4.2.2.1 Return Loss
4.2.2.2 Gain
4.2.2.3 Directivity
4.2.3 4x3 Patch Array antenna
4.2.3.1 Return Loss
4.2.3.2 Gain
4.2.3.3 Directivity
4.2.4 4x4 Patch Array antenna
xiii
4.2.4.1 Return Loss
54
4.2.4.2 Gain
55
4.2.4.3 Directivity
57
4.3 Comparison for Overall Results
5
59
CONCLUSION AND RECOMMENDATION
5.1 Conclusion
62
5.2 Future Work
63
REFERENCES
64
PROJECT PLANNING (GANTT CHART)
67
xiv
LIST OF TABLES
NO
TITLE
PAGE
2.1
Materials Conductivity
18
3.1
Design Specification for WiMAX application
22
4.1
Gain of Single Patch at 2.5GHz
35
4.2
Directivity of Single Patch at 2.5GHz
37
4.3
Gain of 4x1 patch array antenna at 2.5 GHz
40
4.4
Directivity of 4x1 patch array antenna at 2.5 GHz
42
4.5
Gain of 4x2 patch array antenna at 2.5 GHz
45
4.6
Directivity of 4x2 patch array antenna at 2.5 GHz
47
4.7
Gain of 4x3 patch array antenna at 2.5 GHz
50
4.8
Directivity of 4x3 patch array antenna at 2.5 GHz
52
4.9
Gain of 4x4 patch array antenna at 2.5 GHz
55
4.10
Directivity of 4x4 patch array antenna at 2.5 GHz
57
4.11
Overall Results
59
xv
LIST OF FIGURES
NO
TITLE
PAGE
2.1
Representative shapes of microstrip patch element
9
2.2
Basic of patch antenna with transmission line
9
2.3
Patch antenna with quarter wave impedance
10
2.4
Microstrip patch array antenna
11
2.5
Four elements array line impedance design layout
11
2.6
(a) Series Feed
12
(b) Parallel Feed
12
2.7
Illustration of quarter wave impedance matching technique
13
2.8
Radiation Pattern
14
2.9
Rotation of a plane electromagnetic wave and its polarization
15
2.10
Reflection, conduction and dieletric losses
16
2.11
Structure of graphene
18
2.12
Application of grahene OLED
18
3.1
Basic structure of single patch antenna
20
3.2
Four element array line impedance design layout
21
3.3
Matching network of quarter wave (λ/4) transformer
23
3.4
Proposed design of single patch
26
3.5
Example of series feed
26
3.6
Example of corporate (parallel) feed
27
3.7
Layout of four element array antenna with impedance
27
xvi
3.8
Proposed 4x1 patch array antenna
28
3.9
Proposed 4x2 patch array antenna
29
3.10
Proposed 4x3 patch array antenna
29
3.11
Proposed 4x4 patch array antenna
30
3.12
CST Studio Suite Software
31
3.13
Flow chart
32
4.1
Return loss for single patch at 2.5 GHz
34
4.2
Gain for single patch antenna for graphene
35
(t=0.035mm) at 2.5 GHz
4.3
Gain for single patch antenna for graphene
36
(t=0.35nm) at 2.5 GHz
4.4
Gain for single patch antenna for copper at 2.5 GHz
36
4.5
Directivity of single patch antenna for graphene
37
(t=0.035mm) at 2.5 GHz
4.6
Directivity of single patch antenna for graphene
38
(t=0.35nm) at 2.5 GHz
4.7
Directivity for single patch antenna for copper at 2.5 GHz
38
4.8
Return loss for 4x1 patch array antenna at 2.5 GHz
39
4.9
Gain for 4x1 patch array antenna for graphene
40
(t=0.035mm) at 2.5 GHz
4.10
Gain for 4x1 patch array antenna for graphene
41
(t=0.35nm) at 2.5 GHz
4.11
Gain for 4x1 patch array antenna for copper at 2.5 GHz
41
4.12
Directivity for 4x1 patch array antenna for graphene (t=0.035mm)
42
at 2.5 GHz
4.13
Directivity for 4x1 patch array antenna for graphene (t=0.35nm)
43
4.14
Directivity for 4x1 patch array antenna for copper at 2.5GHz
43
4.15
Return loss for 4x2 patch array antenna at 2.5 GHz
44
4.16
Gain for 4x2 patch array antenna for graphene
45
(t=0.035mm) at 2.5 GHz
xvii
4.17
Gain for 4x2 patch array antenna for graphene
46
(t=0.35nm) at 2.5 GHz
4.18
Gain for 4x2 patch array antenna for copper at 2.5 GHz
46
4.19
Directivity for 4x2 patch array antenna for graphene
47
(t=0.035mm) at 2.5 GHz
4.20
Directivity for 4x2 patch array antenna for graphene (t=0.35nm)
48
4.21
Directivity for 4x2 patch array antenna for copper at 2.5GHz
48
4.22
Return loss for 4x3 patch array antenna at 2.5 GHz
49
4.23
Gain for 4x3 patch array antenna for graphene
50
(t=0.035mm) at 2.5 GHz
4.24
Gain for 4x3 patch array antenna for graphene
51
(t=0.35nm) at 2.5 GHz
4.25
Gain for 4x3 patch array antenna for copper at 2.5 GHz
51
4.26
Directivity for 4x3 patch array antenna for graphene (t=0.035mm)
52
at 2.5 GHz
4.27
Directivity for 4x3 patch array antenna for graphene (t=0.35nm)
53
4.28
Directivity for 4x3 patch array antenna for copper at 2.5GHz
53
4.29
Return loss for 4x4 patch array antenna at 2.5 GHz
54
4.30
Gain for 4x4 patch array antenna for graphene (t=0.035mm)
55
at 2.5 GHz
4.31
Gain for 4x4 patch array antenna for graphene (t=0.35nm)
56
at 2.5 GHz
4.32
Gain for 4x4 patch array antenna for copper at 2.5 GHz
56
4.33
Directivity for 4x4 patch array antenna for graphene
57
(t=0.035mm) at 2.5 GHz
4.34
Directivity for 4x4 patch array antenna for graphene (t=0.35nm)
58
4.35
Directivity for 4x4 patch array antenna for copper at 2.5GHz
58
1
CHAPTER 1
INTRODUCTION
This chapter will discuss briefly the background of the project have been
chosen to design and simulate. In this chapter will also discuss the problem statement,
main objective and the scope of the project.
By the passage of time, microstrip antennas became one of the rapid growing
segments in the industry of telecommunication and believed to be the vital and
preferred medium for the future. These days, this type of antenna has a large demand
by the end user and consumer for integrated wireless digital application. Antenna that
will be used in this application such as WiMAX should be low profile, low weight,
low volume and broad bandwidth.[1]
Antenna is a transducer designed to send information as well as collect data in
electromagnetic waves. It transforms electrical power into radio waves and the other
way round so that performing its operation. In other words, the antenna is the
transitional structure between free-space and guiding device. The guiding device or
transmission line may take the form of coaxial line or a hollow waveguide, used to
transport electromagnetic energy from the source to the antenna, or even from the
receiver to the antenna.
2
There are many types of antenna such as wire antennas, aperture antennas,
microstrip antennas, array antennas, lens antennas and so on. Different types of
antenna have different types of application.
1.1 Project Background
This project been proposed to design of microstrip rectangular patch antenna
with centre frequency at 2.5GHz for WiMAX application by using Graphene. The
array of 4 by N (4xN) patch array microstrip rectangular antenna with microstrip line
feeding based on quarter wave impedance matching technique will be done and
simulated by using Computer Simulation Tool (CST) software
[15]
. This design will
replace the patch material of copper with the graphene. There are two thicknesses of
graphene have been used which are 0.035mm and 0.35nm. The graphene could
potentially lead to very interesting features such as miniaturization, dynamic tuning
and even optical transparency and mechanical flexibility [9]. We are also need to vary
in number of arrays to compare the performance for two types of materials such that
copper and graphene. As well as the performance of the single patch designed antenna
was compared for two types of materials in term of return loss, directivity, radiation
pattern and gain. There are also some aspects need to reconsider such that type of
substrate, feeding technique, the thickness and dielectric constant of substrate to meet
a good result. [14]
3
1.1.1 Graphene
Graphene is, simply a single atomic layer of graphite; an ample mineral which
is an allotrope of carbon which is composed of very tightly bonded carbon atoms
orderly into a hexagonal lattice. What might make graphene so unique is its sp2
hybridization and very thin atomic thickness which is 0.345nm. These characteristics
let the graphene to break so many facts in terms of strength, electricity and heat
conduction.
It was theoretically claimed that two dimensional substances failed to exist
because of lack of thermal stability when separated. Still, after graphene was isolated,
obviously that it seemed actually possible, and it took researchers a bit of time to
discover the correct way. After suspended graphene sheets were analysed by
transmitting electron microscopy, researchers stated that they discovered a good
reason of slight rippling in the graphene, altering composition of the material. Even
so, in the future research implies that it is actually simply because of the carbon to
carbon bonds in graphene are so compact and also strong that they avoid thermal
changes from destabilizing it.
Essentially the most beneficial characteristics of graphene is a zero-overlap
semimetal, which the both holes and electrons as charge carrier with very high
electrical conductivity. Carbon atoms have a total of 6 electrons; in graphene, each
atom is linked to 3 other carbon atoms on the two dimensional plane, leaving 1 electron
freely available in the third dimension for electronic conduction. These pi orbitals
overlap and assist to improve the carbon to carbon bonds in graphene. Generally, the
electronic properties of graphene are dictated by the bonding and anti-bonding of these
pi orbitals.
Tests have shown that the electronic mobility of graphene is very high. It is
said that graphene electrons act like photons in their mobility due to their lack of mass.
Graphene also contains elastic properties, being able to retain its initial size after strain.
[4][12] [19]
4
1.2
Problem Statement
Microstrip antenna is preferred due to the some advantages for example low
profile, light weight,
inexpensive, simplicity and versatile in terms of resonant
frequency, polarization, pattern and impedance[3][15]. However, there are some
limitations in microstrip single antenna such that low gain, narrow bandwidth with low
efficiency
[15]
. These disadvantages can be overcome by constructing many patch
antennas in array configuration. This project also has been done to improve the patch
material of the antenna from copper to graphene. Though graphene is the best
conductor known, it is mono-atomic and thus the surface resistance is very high
compared to metals.[21] The conductivity of graphene is very frequency-dependent and
can have completed different behavior [9]. So, the improvement need to be simulate by
CST Studio Suite to prove that graphene is better than copper in term of performance.
1.3
Objectives
The main objective of this project is to design an efficient microstrip
rectangular patch antenna by adding in many patch (4xN) antennas in array for
WiMAX application at 2.5GHz. The design’s performance will be more focus on
return loss, Voltage Standing Wave Ratio (VSWR), bandwidth, directivity, radiation
pattern and gain and will be simulated and tested by CST Studio Suite software.
i.
To design an efficient microstrip square patch antenna by adding in many
patch antennas (4xN) by using graphene as patch material in array for
WiMAX application at 2.5GHz
ii.
To evaluate the performance between the single patch and patch array
microstrip antenna for two types of materials; graphene and copper.
iii.
To identify the advantages and improvement can be done by Graphene
as a patch material.
5
1.4 Project Scope
The design of microstrip rectangular patch antenna with resonant frequency at
2.5GHz been used for WiMAX application. The microstrip line feeding based on
quarter wave impedance matching technique will be fed on the array of four by N
(4xN) patch array microstrip rectangular antenna. This project designed and simulated
by using CST Studio Suite Software. Design single patch and multiple patch antenna
specifically array of 4xN; N=1, 2, 3, 4. Two types of patch material have been used;
graphene with two thicknesses such that 0.035mm and 0.35nm as well as copper to
identify and compare the performance. The tabulation of data and results will be based
on the simulation in the CST Suite Studio software.
1.5 Brief Explanations on Methodology
Many research on the project need to be done to ensure that the project will run
smoothly. Primary stage, need to learn theoretically the concept of microstrip patch
antenna and graphene to implement it in the suggested antenna. Next step, the
designing and simulation process by using the CST software. Last but not least,
analyse the results in term of performance of patch antenna and graphene.
1.6 Thesis Plan
Chapter 1- In this chapter, briefly explain about the introduction or the
background of project. Some of the information about the definition of antenna and
types of antenna also explained. This chapter also including the project background,
problem statement, objectives and project scope.
Chapter 2- In this chapter, the literature review is where the explanations of
past research and journal that related with this project. Past research included the
results, formulas and calculation based on the antenna and the graphene.
6
Chapter 3 - Methodology is a guideline to complete and run the project
smoothly. Start from the research on the related antenna and graphene so that it fulfils
all the requirements in order to meet desired results.
Chapter 4 - In this chapter, it will present all the tabulation data and results. As
the results have been tabulated, the analysis of data can be done. There will also a
discussion about the results.
Chapter 5 - There will a suggestion and future work based on this project. As
well as, the explanation of overall conclusion for the whole project.
7
CHAPTER 2
LITERATURE REVIEW
This chapter review theoretically to get an idea that related with this project so that it
can helps to design and simulate the project by using an appropriate concept. From the
collected information, it can be a guideline in this project to improve the proposed
project so that it works successfully.
2.1 Antenna Definition
Antenna is a very crucial component in communication, broadcasting and radar
system. The definition of antenna is the component which transforms wire propagated
waves into space propagated waves. The antenna gets electromagnetic waves and also
goes by them onto a receiver or sends electromagnetic waves that have been generated
by a transmitter. In other phrase, the transmitter signal energy is delivered into space
by a sending antenna and the signal is then obtained from space by a receiving antenna.
With the role of the antenna, it could be imagining as a gate connecting the
transmission lines and free space.
Antennas are generally categorized in various techniques. One of the
techniques is the frequency band of operation. The rest comprised of physical structure
DESIGN MICROSTRIP SQUARE PATCH ARRAY ANTENNA AT 2.5GHz BY
USING GRAPHENE FOR WiMAX APPLICATION
YULLY ERWANTI BINTI MASRUKIN
This Report Is Submitted In Partial Fulfillment of Requirement for the Bachelor
Degree of Electronic Engineering (Wireless Communication)
Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer
Universiti Teknikal Malaysia Melaka
JUNE 2015
ii
iii
iv
v
Special dedication to my late father, Masrukin Bin Ideris, my lovely mother, Rabi’ah
Binti Hussein and my family.
vi
ACKNOWLEDGEMENT
Alhamdulilah with His blessing and the strengths, I am successfully completed
my project and thesis. First of all, I would like to my special gratitude to my supervisor,
En Azman Bin Awang Teh for his guidance, support and supervision to encounter the
problem in completing my project and thesis.
I also would like to thank PM Dr Zahriladha Bin Zakaria and Engr. Norbayah
Binti Yusop as my panel for PSM I and PSM II for their valuable comment in
improving my project. I am also be thankful to my family for their moral support and
encouragement.
Last but not least, I would to thank to all my friends for their help, knowledge
and assistance to accomplish my project and thesis. To those who indirectly
contributed to this thesis, your kindly means a lot to me.
vii
ABSTRACT
In recent time, there is a very large request by the consumer for integrated wireless
digital applications. Antenna that preferred in this demand should be low profile, light
weight and broad bandwidth. Microstrip antenna be selected to fulfil these
requirement. Due to the restraint of microstrip antenna such that low gain, narrow
bandwidth with low efficiency, constructing many patch in array configuration is
preferred to overwhelm the disadvantages. Nowadays, graphene has attain a great
demand from the device community. In this project, graphene is an element that
preferred in replacing the copper as patch material to improve the performance of
antenna. This is because of its advantages for instance light weight, strong, transparent
and good conductor of heat and electricity. This thesis presents the design of microstrip
square patch antenna with resonant frequency at 2.5GHz for WiMAX application. The
proposed design antennas are single patch and patch array of four by N (4xN) antenna,
which N=1, 2, 3 and 4 for two types of patch materials such as graphene and copper.
Two thickness of graphene been used in this design such that 0.035mm and 0.35nm.
The array of 4xN patch array microstrip square antenna with microstrip line feeding
based on quarter wave impedance matching technique was designed and simulated by
using Computer Simulation Studio 2011 (CST) software. The performance for the
single patch and patch array microstrip antenna for two types of patch materials;
graphene and copper are compared in terms of return loss, gain and directivity. From
the simulation, the highest return loss obtained is -27.16dB, while gain is 6.4520dB
and directivity is 13.180dB. From the overall results, 4x4 patch array antenna of
graphene with the thickness of 0.35nm gives the best performance among the others
in terms of return loss, gain and directivity. In this project, prove that graphene gives
an improvement in the performance of antenna due to its high conductivity.
viii
ABSTRAK
Kebelakangan ini, terdapat banyak permintaan oleh pengguna terhadap aplikasi digital
tanpa wayar. Antena yang dipilih dalam permintaan ini seharusnya berprofil rendah,
ringan dan mempunyai lebar jalur yang besar. Antenna mikrostrip dipilih untuk
memenuhi keperluan ini. Disebabkan kekangan antena mikrostrip seperti gandaan
yang rendah, lebar jalur sempit dengan kecekapan yang rendah, membina banyak
tampal dalam bentuk konfigurasi tatasusunan telah dipilih untuk mengatasi
keburukannya. Pada masa kini, graphene telah mendapat permintaan tinggi daripada
komuniti peranti. Dalam projek ini, graphene adalah unsur yang dipilih untuk
menggantikan tembaga sebagai bahan tampal untuk meningkatkan prestasi antenna.
Ini kerana kelebihannya misalnya seperti ringan, kuat, telus dan konduktor haba dan
elektrik yang baik. Thesis ini membentangkan reka bentuk tampal mikrostrip segi
empat sama dengan frekuensi salunan pada 2.5GHz untuk aplikasi WiMAX.
Cadangan reka bentuk antena adalah satu tampal dan tatasusunan tampal bagi empat
oleh N (4xN) antenna yang N=1, 2, 3 dan 4 untuk dua jenis bahan tampal seperti
graphene dan tembaga. Dua ketebalan graphene telah digunakan dalam reka bentuk ini
iaitu 0.035mm dan 0.35nm. Tatasusunan daripada microstrip tampal segi empat sama
4xN dengan talian suap berasaskan teknik suku gelombang padanan galangan telah
direka dan disimulasi dengan menggunakan perisian Computer Simulation Studio
2011 (CST). Prestasi untuk satu tampal dan tatasusunan antena mickrostrip tampal
untuk dua jenis bahan tampal; graphene dan tembaga dibandingkan dari segi
kehilangan balikan, gandaan dan “direktiviti”. Daripada simulasi, kehilangan balikan
yang paling tinggi dicapai adalah -27.16dB, manakala gandaan adalah 6.4520dB dan
“direktiviti” adalah 13.180dB. Daripada hasil kesuluruhan, 4x4 tatasusunan tampal
daripada graphene dengan ketebalan 0.35nm memberi prestasi yang terbaik antara
yang lain dari segi kehilangan balikan, gandaan dan “direktiviti”. Dalam projek ini
telah membuktikan bahawa graphene telah memberi peningkatan dalam prestasi
antenna disebabkan konduktivitinya yang tinggi.
ix
TABLE OF CONTENT
CHAPTER
1
CONTENT
PAGE
PROJECT TITLE
i
DECLARATION
iii
DEDICATION
v
ACKNOWLEDGEMENT
vi
ABSTRACT
vii
ABSTRAK
viii
TABLE OF CONTENT
ix
LIST OF TABLES
xiii
LIST OF FIGURES
xiv
INTRODUCTION
1
1.1 PROJECT BACKGROUND
1.1.1 Graphene
2
1.2 PROBLEM STATEMENT
4
1.3 OBJECTIVES
4
1.4 PROJECT SCOPES
5
1.5 BRIEFLY EXPLANATION ON
5
3
METHODOLOGY
1.6 THESIS PLAN
5
x
2
LITERATURE REVIEW
2.1 ANTENNA DEFINITION
7
2.2 MICROSTRIP PATCH
8
2.2.1 Rectangular Patch
2.3 ARRAY ANTENNAS
10
2.4 FEED NETWORKS
12
2.5 QUARTER WAVELENGTH TRANSFORMER
13
2.6 PARAMETERS OF ANTENNAS
13
2.6.1 Radiation Pattern
14
2.6.2 Directivity
14
2.6.3 Bandwidth
15
2.6.4 Polarization
15
2.6.5 Antenna Efficiency
16
2.6.6 Gain
16
2.6.7 VSWR
16
17
2.7 GRAPHENE
3
10
METHODOLOGY
3.1 OVERVIEW OF METHODOLOGY
19
3.2 SUBSTRATE MATERIAL
22
3.3 DESIGNING ANTENNA
23
3.3.1 Single Microstrip Patch Design
23
3.3.1.1 Calculation of Patch Design
24
3.3.1.2 Calculation of Impedance for
25
Quarter-Wave Transformer
xi
26
28
28
28
31
32
34
34
35
37
39
39
39
40
42
44
44
45
47
49
49
50
52
54
xii
3.3.2 Microstrip Patch Array Antenna Design
3.3.2.1 Patch Calculation
3.3.2.2 Calculation of Impedance for
Quarter-Wave Transformer
3.3.3 Design of 4xN Patch Array Antenna
3.3.4 Introduction to CST 2011 Studio Suite Software
3.3.5 Flowchart
4
RESULTS AND DISCUSSION
4.1 Single Patch Antenna
4.1.1 Return Loss
4.1.2 Gain
4.1.3 Directivity
4.2 Patch Array Antenna
4.2.1 4x1 Patch Array antenna
4.2.1.1 Return Loss
4.2.1.2 Gain
4.2.1.3 Directivity
4.2.2 4x2 Patch Array antenna
4.2.2.1 Return Loss
4.2.2.2 Gain
4.2.2.3 Directivity
4.2.3 4x3 Patch Array antenna
4.2.3.1 Return Loss
4.2.3.2 Gain
4.2.3.3 Directivity
4.2.4 4x4 Patch Array antenna
xiii
4.2.4.1 Return Loss
54
4.2.4.2 Gain
55
4.2.4.3 Directivity
57
4.3 Comparison for Overall Results
5
59
CONCLUSION AND RECOMMENDATION
5.1 Conclusion
62
5.2 Future Work
63
REFERENCES
64
PROJECT PLANNING (GANTT CHART)
67
xiv
LIST OF TABLES
NO
TITLE
PAGE
2.1
Materials Conductivity
18
3.1
Design Specification for WiMAX application
22
4.1
Gain of Single Patch at 2.5GHz
35
4.2
Directivity of Single Patch at 2.5GHz
37
4.3
Gain of 4x1 patch array antenna at 2.5 GHz
40
4.4
Directivity of 4x1 patch array antenna at 2.5 GHz
42
4.5
Gain of 4x2 patch array antenna at 2.5 GHz
45
4.6
Directivity of 4x2 patch array antenna at 2.5 GHz
47
4.7
Gain of 4x3 patch array antenna at 2.5 GHz
50
4.8
Directivity of 4x3 patch array antenna at 2.5 GHz
52
4.9
Gain of 4x4 patch array antenna at 2.5 GHz
55
4.10
Directivity of 4x4 patch array antenna at 2.5 GHz
57
4.11
Overall Results
59
xv
LIST OF FIGURES
NO
TITLE
PAGE
2.1
Representative shapes of microstrip patch element
9
2.2
Basic of patch antenna with transmission line
9
2.3
Patch antenna with quarter wave impedance
10
2.4
Microstrip patch array antenna
11
2.5
Four elements array line impedance design layout
11
2.6
(a) Series Feed
12
(b) Parallel Feed
12
2.7
Illustration of quarter wave impedance matching technique
13
2.8
Radiation Pattern
14
2.9
Rotation of a plane electromagnetic wave and its polarization
15
2.10
Reflection, conduction and dieletric losses
16
2.11
Structure of graphene
18
2.12
Application of grahene OLED
18
3.1
Basic structure of single patch antenna
20
3.2
Four element array line impedance design layout
21
3.3
Matching network of quarter wave (λ/4) transformer
23
3.4
Proposed design of single patch
26
3.5
Example of series feed
26
3.6
Example of corporate (parallel) feed
27
3.7
Layout of four element array antenna with impedance
27
xvi
3.8
Proposed 4x1 patch array antenna
28
3.9
Proposed 4x2 patch array antenna
29
3.10
Proposed 4x3 patch array antenna
29
3.11
Proposed 4x4 patch array antenna
30
3.12
CST Studio Suite Software
31
3.13
Flow chart
32
4.1
Return loss for single patch at 2.5 GHz
34
4.2
Gain for single patch antenna for graphene
35
(t=0.035mm) at 2.5 GHz
4.3
Gain for single patch antenna for graphene
36
(t=0.35nm) at 2.5 GHz
4.4
Gain for single patch antenna for copper at 2.5 GHz
36
4.5
Directivity of single patch antenna for graphene
37
(t=0.035mm) at 2.5 GHz
4.6
Directivity of single patch antenna for graphene
38
(t=0.35nm) at 2.5 GHz
4.7
Directivity for single patch antenna for copper at 2.5 GHz
38
4.8
Return loss for 4x1 patch array antenna at 2.5 GHz
39
4.9
Gain for 4x1 patch array antenna for graphene
40
(t=0.035mm) at 2.5 GHz
4.10
Gain for 4x1 patch array antenna for graphene
41
(t=0.35nm) at 2.5 GHz
4.11
Gain for 4x1 patch array antenna for copper at 2.5 GHz
41
4.12
Directivity for 4x1 patch array antenna for graphene (t=0.035mm)
42
at 2.5 GHz
4.13
Directivity for 4x1 patch array antenna for graphene (t=0.35nm)
43
4.14
Directivity for 4x1 patch array antenna for copper at 2.5GHz
43
4.15
Return loss for 4x2 patch array antenna at 2.5 GHz
44
4.16
Gain for 4x2 patch array antenna for graphene
45
(t=0.035mm) at 2.5 GHz
xvii
4.17
Gain for 4x2 patch array antenna for graphene
46
(t=0.35nm) at 2.5 GHz
4.18
Gain for 4x2 patch array antenna for copper at 2.5 GHz
46
4.19
Directivity for 4x2 patch array antenna for graphene
47
(t=0.035mm) at 2.5 GHz
4.20
Directivity for 4x2 patch array antenna for graphene (t=0.35nm)
48
4.21
Directivity for 4x2 patch array antenna for copper at 2.5GHz
48
4.22
Return loss for 4x3 patch array antenna at 2.5 GHz
49
4.23
Gain for 4x3 patch array antenna for graphene
50
(t=0.035mm) at 2.5 GHz
4.24
Gain for 4x3 patch array antenna for graphene
51
(t=0.35nm) at 2.5 GHz
4.25
Gain for 4x3 patch array antenna for copper at 2.5 GHz
51
4.26
Directivity for 4x3 patch array antenna for graphene (t=0.035mm)
52
at 2.5 GHz
4.27
Directivity for 4x3 patch array antenna for graphene (t=0.35nm)
53
4.28
Directivity for 4x3 patch array antenna for copper at 2.5GHz
53
4.29
Return loss for 4x4 patch array antenna at 2.5 GHz
54
4.30
Gain for 4x4 patch array antenna for graphene (t=0.035mm)
55
at 2.5 GHz
4.31
Gain for 4x4 patch array antenna for graphene (t=0.35nm)
56
at 2.5 GHz
4.32
Gain for 4x4 patch array antenna for copper at 2.5 GHz
56
4.33
Directivity for 4x4 patch array antenna for graphene
57
(t=0.035mm) at 2.5 GHz
4.34
Directivity for 4x4 patch array antenna for graphene (t=0.35nm)
58
4.35
Directivity for 4x4 patch array antenna for copper at 2.5GHz
58
1
CHAPTER 1
INTRODUCTION
This chapter will discuss briefly the background of the project have been
chosen to design and simulate. In this chapter will also discuss the problem statement,
main objective and the scope of the project.
By the passage of time, microstrip antennas became one of the rapid growing
segments in the industry of telecommunication and believed to be the vital and
preferred medium for the future. These days, this type of antenna has a large demand
by the end user and consumer for integrated wireless digital application. Antenna that
will be used in this application such as WiMAX should be low profile, low weight,
low volume and broad bandwidth.[1]
Antenna is a transducer designed to send information as well as collect data in
electromagnetic waves. It transforms electrical power into radio waves and the other
way round so that performing its operation. In other words, the antenna is the
transitional structure between free-space and guiding device. The guiding device or
transmission line may take the form of coaxial line or a hollow waveguide, used to
transport electromagnetic energy from the source to the antenna, or even from the
receiver to the antenna.
2
There are many types of antenna such as wire antennas, aperture antennas,
microstrip antennas, array antennas, lens antennas and so on. Different types of
antenna have different types of application.
1.1 Project Background
This project been proposed to design of microstrip rectangular patch antenna
with centre frequency at 2.5GHz for WiMAX application by using Graphene. The
array of 4 by N (4xN) patch array microstrip rectangular antenna with microstrip line
feeding based on quarter wave impedance matching technique will be done and
simulated by using Computer Simulation Tool (CST) software
[15]
. This design will
replace the patch material of copper with the graphene. There are two thicknesses of
graphene have been used which are 0.035mm and 0.35nm. The graphene could
potentially lead to very interesting features such as miniaturization, dynamic tuning
and even optical transparency and mechanical flexibility [9]. We are also need to vary
in number of arrays to compare the performance for two types of materials such that
copper and graphene. As well as the performance of the single patch designed antenna
was compared for two types of materials in term of return loss, directivity, radiation
pattern and gain. There are also some aspects need to reconsider such that type of
substrate, feeding technique, the thickness and dielectric constant of substrate to meet
a good result. [14]
3
1.1.1 Graphene
Graphene is, simply a single atomic layer of graphite; an ample mineral which
is an allotrope of carbon which is composed of very tightly bonded carbon atoms
orderly into a hexagonal lattice. What might make graphene so unique is its sp2
hybridization and very thin atomic thickness which is 0.345nm. These characteristics
let the graphene to break so many facts in terms of strength, electricity and heat
conduction.
It was theoretically claimed that two dimensional substances failed to exist
because of lack of thermal stability when separated. Still, after graphene was isolated,
obviously that it seemed actually possible, and it took researchers a bit of time to
discover the correct way. After suspended graphene sheets were analysed by
transmitting electron microscopy, researchers stated that they discovered a good
reason of slight rippling in the graphene, altering composition of the material. Even
so, in the future research implies that it is actually simply because of the carbon to
carbon bonds in graphene are so compact and also strong that they avoid thermal
changes from destabilizing it.
Essentially the most beneficial characteristics of graphene is a zero-overlap
semimetal, which the both holes and electrons as charge carrier with very high
electrical conductivity. Carbon atoms have a total of 6 electrons; in graphene, each
atom is linked to 3 other carbon atoms on the two dimensional plane, leaving 1 electron
freely available in the third dimension for electronic conduction. These pi orbitals
overlap and assist to improve the carbon to carbon bonds in graphene. Generally, the
electronic properties of graphene are dictated by the bonding and anti-bonding of these
pi orbitals.
Tests have shown that the electronic mobility of graphene is very high. It is
said that graphene electrons act like photons in their mobility due to their lack of mass.
Graphene also contains elastic properties, being able to retain its initial size after strain.
[4][12] [19]
4
1.2
Problem Statement
Microstrip antenna is preferred due to the some advantages for example low
profile, light weight,
inexpensive, simplicity and versatile in terms of resonant
frequency, polarization, pattern and impedance[3][15]. However, there are some
limitations in microstrip single antenna such that low gain, narrow bandwidth with low
efficiency
[15]
. These disadvantages can be overcome by constructing many patch
antennas in array configuration. This project also has been done to improve the patch
material of the antenna from copper to graphene. Though graphene is the best
conductor known, it is mono-atomic and thus the surface resistance is very high
compared to metals.[21] The conductivity of graphene is very frequency-dependent and
can have completed different behavior [9]. So, the improvement need to be simulate by
CST Studio Suite to prove that graphene is better than copper in term of performance.
1.3
Objectives
The main objective of this project is to design an efficient microstrip
rectangular patch antenna by adding in many patch (4xN) antennas in array for
WiMAX application at 2.5GHz. The design’s performance will be more focus on
return loss, Voltage Standing Wave Ratio (VSWR), bandwidth, directivity, radiation
pattern and gain and will be simulated and tested by CST Studio Suite software.
i.
To design an efficient microstrip square patch antenna by adding in many
patch antennas (4xN) by using graphene as patch material in array for
WiMAX application at 2.5GHz
ii.
To evaluate the performance between the single patch and patch array
microstrip antenna for two types of materials; graphene and copper.
iii.
To identify the advantages and improvement can be done by Graphene
as a patch material.
5
1.4 Project Scope
The design of microstrip rectangular patch antenna with resonant frequency at
2.5GHz been used for WiMAX application. The microstrip line feeding based on
quarter wave impedance matching technique will be fed on the array of four by N
(4xN) patch array microstrip rectangular antenna. This project designed and simulated
by using CST Studio Suite Software. Design single patch and multiple patch antenna
specifically array of 4xN; N=1, 2, 3, 4. Two types of patch material have been used;
graphene with two thicknesses such that 0.035mm and 0.35nm as well as copper to
identify and compare the performance. The tabulation of data and results will be based
on the simulation in the CST Suite Studio software.
1.5 Brief Explanations on Methodology
Many research on the project need to be done to ensure that the project will run
smoothly. Primary stage, need to learn theoretically the concept of microstrip patch
antenna and graphene to implement it in the suggested antenna. Next step, the
designing and simulation process by using the CST software. Last but not least,
analyse the results in term of performance of patch antenna and graphene.
1.6 Thesis Plan
Chapter 1- In this chapter, briefly explain about the introduction or the
background of project. Some of the information about the definition of antenna and
types of antenna also explained. This chapter also including the project background,
problem statement, objectives and project scope.
Chapter 2- In this chapter, the literature review is where the explanations of
past research and journal that related with this project. Past research included the
results, formulas and calculation based on the antenna and the graphene.
6
Chapter 3 - Methodology is a guideline to complete and run the project
smoothly. Start from the research on the related antenna and graphene so that it fulfils
all the requirements in order to meet desired results.
Chapter 4 - In this chapter, it will present all the tabulation data and results. As
the results have been tabulated, the analysis of data can be done. There will also a
discussion about the results.
Chapter 5 - There will a suggestion and future work based on this project. As
well as, the explanation of overall conclusion for the whole project.
7
CHAPTER 2
LITERATURE REVIEW
This chapter review theoretically to get an idea that related with this project so that it
can helps to design and simulate the project by using an appropriate concept. From the
collected information, it can be a guideline in this project to improve the proposed
project so that it works successfully.
2.1 Antenna Definition
Antenna is a very crucial component in communication, broadcasting and radar
system. The definition of antenna is the component which transforms wire propagated
waves into space propagated waves. The antenna gets electromagnetic waves and also
goes by them onto a receiver or sends electromagnetic waves that have been generated
by a transmitter. In other phrase, the transmitter signal energy is delivered into space
by a sending antenna and the signal is then obtained from space by a receiving antenna.
With the role of the antenna, it could be imagining as a gate connecting the
transmission lines and free space.
Antennas are generally categorized in various techniques. One of the
techniques is the frequency band of operation. The rest comprised of physical structure