UNIVERSITI PUTRA MALAYSIA

HIGH GAIN COMPACT ANTENNA DESIGN FOR UNDERWATER COMMUNICATION

SAMA FOUAD MAJEED

FK 2018 55

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HIGH GAIN COMPACT ANTENNA DESIGN FOR UNDERWATER COMMUNICATION

By

SAMA ����� MAJEED

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfillment of the Requirements for the Degree of Master of Science

������ 2017

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COPYRIGHT

All material contained within the thesis, including without limitation text, logos,

icons, photographs, and all other artwork, is copyright material of Universiti Putra

Malaysia unless otherwise stated. Use may be made of any material contained within

the thesis for non-commercial purposes from the copyright holder. Commercial use

of material may only be made with the express, prior, written permission of

Universiti Putra Malaysia.

Copyright © Universiti Putra Malaysia

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DEDICATION

This thesis is dedicated to my parents Awatif Hussien and Fouad Majeed

For their endless love, support and encouragement…

To my lovely sisters and brother (Rawaa, Sura and Aws)…

To all my supportive friends

To every striving muhsin person who is constantly improving aspects of life…

To those who are compassionate towards achieving perfection (ihsaan)… To the consistent pursuers of knowledge aiming for positive change…

A special contribution to my home country Iraq and to Malaysia; With lots of gratitude…

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment

of the requirement for the degree of Master of Science

HIGH GAIN COMPACT ANTENNA DESIGHN FOR UNDERWATER COMMUNICATION

By

SAMA ����� MAJEED

�������2017

Chairman : Alyani Ismail, PhD Faculty : Engineering

Nowadays, communications technology is developing rapidly and becoming more

advanced each day. In turn, the demand for this technology is also increasing.

Underwater communication is not an exception; it has received the attentions of

scientists working in the communications and telecommunication field. Two types of

waves have been used in underwater communications and systems mostly. These are

known as electromagnetic and sonar waves. Research findings show that

electromagnetic waves yield more promising results when submerging

communication devices in water. However, electromagnetic wave applications have

also issues on it is own to address.

The performance of electromagnetic waves degrades exponentially when submerged

in a medium such as water. Due to this reduction in wave energy, many hubs and

transceivers should be used to cover an area for transferring data from one station to

the other. In addition, the demand for free licensed frequency bands such as

industrial scientific and medical (ISM) and wireless local area network (WLAN) has

forced users to require more band width (BW) and a higher data transfer rate. Thus,

higher frequency bands such as microwave (MW) frequency bands are required.

However, higher bands than microwave bands also degrade in water, where the wave

distance will become too short. Hence, a higher data transfer rate and smaller

dimensions of the microwave instruments are required for underwater

communications compared to electromagnetic waves in a lower band, sonar and

ultra-sonic waves, and microwave, which can be a promising technology to apply for

submerged communications.

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A compact-sized high gain photonic band gab (PBG) structure stack antenna

resonating at 2.4 GHz and also a compact high gain ultra wide band antenna (UWB)

resonating at (1.65–6.8) GHz for ISM band and WLAN are presented in this thesis.

Simulation and measurement results have been investigated and then the behaviour

of the antennas on the reflection coefficient, antenna pattern and gain are also

studied. The proposed microstrip antenna is designed at 2.4 GHz, achieving a

miniaturized size by almost 20%, a higher gain, and higher efficiency at the desired

harmonics in air and water compared to similar previous experiments. However, not

many antennas have been designed for underwater communications and most are

quite bulky. The performance of the antenna submerged in water was measured in

three ways: with both antennas submerged in water, one at the surface, and the other

inserted in water, followed by depth valuation. When both are submerged in water,

the reflection coefficient is shifted to a lower frequency band (0.86 GHz) with an

increase in distance between the antennas. The proposed antenna is working at an

ISM lower band (0.91 GHz) when both are in water. Besides that, at distances of

more than 350 mm, some more resonances occur at 1.5 GHz, 1.8 GHz, and even 2.4

GHz at 500 mm distance. The depth variation of the antenna was performed in a

depth from 3–25 cm.

The same procedure is applied to the UWB antenna for measurement in water. When

the antennas are inserted in water or even face the water, the broad BW of the

antennas is degraded, especially at higher frequencies higher than 4 GHz. There is

not much of a difference between the measurements when both are positioned in

water and when one is put on the surface only. However, keeping one antenna on the

surface and inserting another in the water can cause the antennas to resonate like

three-band antennas working at lower bands. The differences between them occur

when both antennas are inserted and one at the surface is the middle band. The

middle band is more effective when both antennas are inserted in water and degraded

with distance increment.

For future work and further studies in underwater communications, the size of the

testing medium can be increased. Thus, further distances can be considered in the

testing procedure and investigations. Besides that, the number of antenna arrays can

be increased to achieve increased range of transmitted data.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Master Sains

REKABENTUK ANTENNA DENGAN KENAIKAN YANG TINGGI UNTUK KOMUNIKASI DALAM AIR

Oleh

SAMA ����� MAJEED

� ���� 2017

Pengerusi : Alyani Ismail, PhD Fakulti : Kejuruteraan

Pada masa kini, teknologi komunikasi berkembang pesat dan menjadi lebih maju

setiap hari. Sebaliknya, permintaan untuk teknologi ini juga semakin meningkat.

Komunikasi bawah air bukan pengecualian; ia telah menerima perhatian saintis yang

bekerja di bidang komunikasi dan telekomunikasi. Dua jenis gelombang telah

digunakan dalam komunikasi dan sistem bawah laut. Ini dikenali sebagai gelombang

elektromagnetik dan sonar. Penemuan penyelidikan menunjukkan bahawa

gelombang elektromagnet menghasilkan hasil yang lebih menjanjikan apabila

peranti komunikasi penyerapan di dalam air. Walau bagaimanapun, aplikasi

gelombang elektromagnet juga telah memperkenalkan lebih banyak masalah.

Persembahan gelombang elektromagnet merendahkan secara eksponen apabila

tenggelam dalam medium seperti air. Disebabkan pengurangan tenaga gelombang

ini, banyak hab dan transceiver harus digunakan untuk menutup kawasan untuk

memindahkan data dari satu stesen ke stesen yang lain. Di samping itu, permintaan

untuk band frekuensi berlesen percuma seperti ISM dan WLAN telah memaksa

pengguna untuk memerlukan lebih banyak BW dan kadar pemindahan data yang

lebih tinggi. Oleh itu, mereka memerlukan band frekuensi tinggi seperti band

frekuensi MW. Walau bagaimanapun, band yang lebih tinggi daripada band MW

juga merosot di dalam air, di mana jarak gelombang akan menjadi terlalu pendek.

Oleh itu, kadar pemindahan data yang lebih tinggi dan dimensi yang lebih kecil

daripada instrumen MW diperlukan untuk komunikasi bawah air berbanding

gelombang elektromagnetik dalam gelombang rendah, sonar dan gelombang ultra

sonik, dan MW, yang boleh menjadi teknologi yang menjanjikan untuk memohon

komunikasi yang terendam.

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Reka bentuk struktur PBG keuntungan bertingkat tinggi yang bersaiz padat

berukuran 2,4 GHz dan juga keuntungan tinggi padat UWB berseri pada (1.65-6.8)

GHz untuk band ISM dan WLAN dibentangkan dalam tesis ini. Hasil simulasi dan

pengukuran telah diselidiki dan kemudian tingkah laku antena pada koefisien

pantulan, corak antena dan keuntungan juga dikaji. Antaramuka microstrip yang

dicadangkan direka pada 2.4 GHz, mencapai saiz miniatur dengan hampir 20%,

keuntungan yang lebih tinggi, dan kecekapan yang lebih tinggi pada harmonik yang

diinginkan di udara dan air berbanding eksperimen sebelumnya yang serupa. Walau

bagaimanapun, tidak banyak antena direka untuk komunikasi bawah air dan

kebanyakannya agak besar. Prestasi antena yang tenggelam dalam air diukur dalam

tiga cara: dengan kedua-dua antena tenggelam dalam air, satu di permukaan, dan

yang lain dimasukkan ke dalam air, diikuti oleh penilaian mendalam. Apabila kedua-

duanya tenggelam di dalam air, pekali refleksi dipindahkan ke band frekuensi rendah

(0.86 GHz) dengan peningkatan jarak antara antena. Antena yang dicadangkan ini

berfungsi pada band rendah ISM (0.91 GHz) apabila keduanya berada di dalam air.

Di samping itu, pada jarak lebih daripada 350 mm, sesetengah resonans berlaku pada

1.5 GHz, 1.8 GHz, dan juga 2.4 GHz pada jarak 500 mm. Variasi kedalaman antena

dilakukan secara mendalam dari 3-25 cm.

Prosedur yang sama digunakan untuk antena UWB untuk pengukuran dalam air.

Apabila antena dimasukkan ke dalam air atau menghadapi air, BW luas antena

dihina, terutama pada frekuensi yang lebih tinggi lebih tinggi daripada 4 GHz. Tidak

banyak perbezaan di antara pengukuran apabila kedua-duanya diposisikan di dalam

air dan apabila seseorang diletakkan di permukaan sahaja. Walau bagaimanapun,

menjaga satu antena di permukaan dan memasukkan satu lagi di dalam air boleh

menyebabkan antena menghidupkan seperti antena tiga jalur yang bekerja pada band

yang lebih rendah. Perbezaan di antara mereka berlaku apabila kedua-dua antena

dimasukkan dan satu di permukaan adalah band tengah. Band tengah lebih berkesan

apabila kedua-dua antena dimasukkan ke dalam air dan terdegradasi dengan

kenaikan jarak.

Untuk kerja masa depan dan kajian lanjut dalam komunikasi bawah air, saiz medium

ujian boleh ditingkatkan. Oleh itu, jarak selanjutnya boleh dipertimbangkan dalam

prosedur ujian dan penyiasatan. Selain itu, bilangan susunan antena boleh

ditingkatkan untuk mencapai rangkaian data yang semakin meningkat.

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ACKNOWLEDGEMENTS

The deepest gratitude is to ALLAH (Subhanahu wa ta’ala) who guided and aided me to make this work possible and to his mercy that enabled me to conduct my studies

with patience.I feel deeply indebted to my supervisor, AP. Dr. Alyani Ismail, for her

patience, guidance, constant supervision, creative advising and personal

involvement throughout the progression of this work. She has been, for me,

not only a source of inspiration and encouragement, but also a model of ideal

academic relations. Much of what I have learned during the progress of this thesis, I

owe, in fact, to AP. Dr Alyani. Working under the supervision of a very great

investigator of the highest academic and human caliber like AP. Dr Alyani has

formed me and will continue to be an unforgettable and a unique experience of

my life. I would like to express my great appreciation and gratitude to my co-

supervisor AP. Dr. Aduwati Sali for her guidance, advice and moral support. .

I am grateful as well to my parents Awatif Hussain and Fouad Majeed for

encouraging me and supporting me in every possible way to continue my studies. I

am really thankful to ALLAH for having such great parents.

I would like to acknowledge the other people who have helped and encouraged me.

I want to thank my sisters Sura Majeed, Rawaa Majeed and my brother Aws Majeed

and all those whom have ever supported me or helped me throughout my studies.

Last but not least, I am deeply indebted, My thanks go to all my lectures at

Universiti Putra Malaysia who taught me during my graduate study at the

University. I am thankful to the Department of Computer and Communication

Engineering, Univsersiti Putra Malaysia for offering all facilities and the academic

environments that made this work possible.

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This thesis was submitted to the Senate of the Universiti Putra Malaysia and has

been accepted as fulfilment of the requirement for the degree of Master of Science.

The members of the Supervisory Committee were as follows:

Alyani Ismail, PhD Associate Professor

Faculty of Engineering

Universiti Putra Malaysia

(Chairman)

Aduwati Sali, PhD Associate Professor

Faculty of Engineering

Universiti Putra Malaysia

(Member)

ROBIAH BINTI YUNUS, PhD Professor and Dean

School of Graduate Studies

Universiti Putra Malaysia

Date:

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Declaration by graduate student

I hereby confirm that:

� this thesis is my original work;

� quotations, illustrations and citations have been duly referenced;

� this thesis has not been submitted previously or concurrently for any other degree

at any institutions;

� intellectual property from the thesis and copyright of thesis are fully-owned by

Universiti Putra Malaysia, as according to the Universiti Putra Malaysia

(Research) Rules 2012;

� written permission must be obtained from supervisor and the office of Deputy

Vice-Chancellor (Research and innovation) before thesis is published (in the

form of written, printed or in electronic form) including books, journals,

modules, proceedings, popular writings, seminar papers, manuscripts, posters,

reports, lecture notes, learning modules or any other materials as stated in the

Universiti Putra Malaysia (Research) Rules 2012;

� there is no plagiarism or data falsification/fabrication in the thesis, and scholarly

integrity is upheld as according to the Universiti Putra Malaysia (Graduate

Studies) Rules 2003 (Revision 2012-2013) and the Universiti Putra Malaysia

(Research) Rules 2012. The thesis has undergone plagiarism detection software

Signature: Date:

Name and Matric No: Sama ����� Majeed, GS43308

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Declaration by Members of Supervisory Committee

This is to confirm that:

� the research conducted and the writing of this thesis was under our supervision;

� supervision responsibilities as stated in the Universiti Putra Malaysia (Graduate

Studies) Rules 2003 (Revision 2012-2013) were adhered to.

Signature:

Name of Chairman

of Supervisory

Committee:

Associate Professor Dr. Alyani Ismail

Signature:

Name of Member

of Supervisory

Committee:

Associate Professor Dr. Aduwati Sali

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TABLE OF CONTENTS

Page

ABSTRACT i

ABSTRAK iii

ACKNOWLEDGEMENTS v

APPROVAL vi

DECLARATION viii

LIST OF TABLES xiii

LIST OF FIGURES xiv

LIST OF ABBREVIATIONS xix

CHAPTER1 INTRODUCTION 1

1.1 Study Background 1 1.2 Statement of Problems and Motivations 1 1.3 Objectives of study 3 1.4 Study Scope 3 1.5 Research Methodology 5 1.6 Thesis Configuration 7

2 LITERATURE REVIEW 8 2.1 Underwater Communications 8

8 9 9

12 13 13

2.1.1 Introduction

2.1.2 ����Input Impedance (���)2.1.3 VSWR

2.1.4 Radiation Properties (Directivity & Gain)

2.1.5 Polarization

2.1.6 Bandwidth (BW)

2.1.7 Z, Y and Scattering Parameters 14 2.2 Microstrip Antenna Basics 15 2.3 Analysis of Microstrip Antennas 16 2.4 Transmission Line (TL) Model 17 2.5 Rectangular Microstrip Antennas 20 2.6 Circular Disc and Ring Antennas 20 2.7 Microstrip Slot Antennas 20 2.8 Defected Ground Structures (DGS) and Photonic Band Gap

(PBG) 21 2.9 Ultra-Wide Band (UWB) Planar Antenna 22

2.9.1 Initial assumptions for UWB Antenna 22 2.9.2 Return Loss (Reflection coefficient) 25 2.9.3 Radiation Efficiency 25 2.9.4 Radiation Pattern and Directivity 26

2.10 Research on Antennas Designed For Underwater and Other

Applications 28

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2.11 Summary 28

3 METHODOLOGY 29 3.1 ���������� 29 3.2 31

31 33

3.3 33

����� ������������3.2.1 Microstrip Antenna Equations

3.2.2 Size Reduction Techniques

Simulation of the Proposed Antennas

3.3.1 Simulation of the Basic Antenna at 2.4 GHz 33 3.3.1.1 Conventional Rectangular microstrip antenna

at 2.4 GHz 35 3.3.1.2 Proposed Rectangular Patch Cut by Three

Slots as PBG Structure 37 3.3.1.3 Proposed Rectangular Patch Simulated in

Water 42 3.3.1.4 Conventional Rectangular Microstrip

Antenna Fed by Transmission Line at 2.4

GHz 43 3.3.2 UWB antenna design 58

3.3.2.1 Design for UWB Antenna 58 3.3.2.2 Conventional UWB elliptical antenna 59 3.3.2.3 CPW UWB Antenna with Stair Case GND 60 3.3.2.4 Final design of the suggested UWB antenna 66 3.3.2.5 Simulation Results of UWB Antenna in Air

and Water for Each Step 67 3.4 Underwater Experimental Setup 82

4 RESULT AND DISSCUSION 85 4.1 Simulated and measured result for the proposed 2.4 GHz

antenna 85 4.1.1 Proposed Rectangular Patch Cut by PBG Structure

simulated and measured in air 85 4.1.2 Proposed Rectangular Patch Cut by Three Slots as PBG

Structure Simulated in Water 86 4.2 The simulated and measured result for the UWB antenna 86

4.2.1 The Final Design of simulated Proposed UWB Antenna

in air 86 4.2.2 Proposed UWB Antenna Measurement in air 89

4.3 Measurement Results of the Proposed Antennas in Water 89 4.3.1 2.4 GHz proposed antenna measurement in water 89 4.3.2 Proposed UWB antenna measurement in water 96

4.4 Summary 103

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5 CONCLUSION AND RECOMMENDATIONS FOR FUTURE WORK 104 5.1 Conclusion 104

5.1.1 Proposed Microstrip Patch Antenna with Rectangular

Shape at 2.4 GHz 104 5.1.2 Proposed UWB Microstrip Antenna 105

5.2 Recommendation for Future Work 105 5.3 Contribution of the Study 105

REFERENCES 106 BIODATA OF STUDENT 112 LIST OF PUBLICATIONS 113

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LIST OF TABLES

Table Page

2.1 VSWR 11

2.2 Types of wide band and ultrawideband (UWB) microstrip antenna 27

3.1 Normal monopole microstrip antenna at 2.4 MHz 34

3.2 Conventional Rectangular microstrip antenna dimensions 36

3.3 The rectangular microstrip antenna with second layer at the front 37

3.4 The dimensions PBG structure applied on the patch 38

3.5 The conventional rectangular microstrip antenna fed by TL’s radiation 44

3.6 Conventional Rectangular Microstrip Antenna Fed by CPW at 2.4

GHz

45

3.7 Radiation pattern of one layer added to the antenna along with an air

layer in between

48

3.8 Radiation characteristics adding second layer with two elliptical rings

behind

51

3.9 Radiation characteristics adding offset 52

3.10 Radiation pattern of cutting PBG 1 54

3.11 Radiation characteristics results of proposed rectangular patch cut by

three slots as PBG Structure

56

3.12 The normal UWB microstrip antenna dimensions with elliptical shape 60

3.13 Staircase CPW UWB antenna dimensions 63

4.1 ( 2.4 GHZ ) microstrip antenna comparison with recent existing works 103

4.2 The proposed UWB antenna’s comparison with some recent and similar works

103

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LIST OF FIGURES

Figure Page

1.1 Study scope 4

1.2 Methodology flowchart 6

2.1 Three dimension radiation pattern of a directional antenna with main

lobe in z-direction

13

2.2 Microstrip antenna structure 15

2.3 Current distribution 16

2.4 TL model and the equivalent circuit 17

2.5 Structure of an antenna with feeding from the back 19

2.6 Side feed of microstrip antenna 19

2.7 Slot antenna structure 21

2.8 Antenna with elliptical shape in patch 23

2.9 Microstrip antenna with a horizontal elliptical shape in patch 24

2.10 Side view of patch antenna 25

3.1 Research flowchart 30

3.2 Normal monopole microstrip antenna at 2.4 GHz 34

3.3 Flowchart of the 2.4 GHz antenna design 35

3.4 Convectional rectangular microstrip antenna at 2.4 GHz 36

3.5 The PBG structure applied on the patch 38

3.6 The ground view of the etched slot 39

3.7 PBG structures with current distribution around the slots 40

3.8 Side view of the antenna at this step 40

3.9 Elliptical resonator of the second layer 41

3.10 The proposed antenna 42

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3.11 Proposed Rectangular Patch Cut by Three Slots as PBG Structure

Simulated in Water

43

3.12 The conventional rectangular microstrip antenna fed by TL 44

3.13 The radiation pattern of conventional rectangular microstrip antenna

fed by TL

44

3.14 Conventional Rectangular Microstrip Antenna Fed by CPW at 2.4

GHz reflection coefficient results

45

3.15 Comparison between the TL feeding and CPW feeding 46

3.16 The radiation pattern of conventional Rectangular Microstrip Antenna

Fed by CPW at 2.4 GHz

46

3.17 One layer added to the antenna along with an air layer in between 47

3.18 One layer added to the antenna along with an air layer in between

radiation pattern

48

3.19 Reflection coefficient result of adding second layer with two elliptical

rings behind

49

3.20 Comparison when second layer and the rings have been added 50

3.21 Radiation pattern adding second layer with two elliptical rings behind 51

3.22 Reflection coefficient result of adding offset 52

3.23 Radiation pattern adding offset 52

3.24 Reflection Coefficient Cutting PBG 1 53

3.25 Radiation pattern Cutting PBG 1 54

3.26 Proposed Rectangular Patch Cut by Three Slots as PBG Structure 55

3.27 Radiation pattern of proposed rectangular patch cut by three slots as

PBG Structure

55

3.28 Comparison results of the cutting PBG structure steps (a: step 1

(19mm, 15mm, 9mm), b: step 2 (20mm, 16mm, 8mm), c: step3

(21mm, 19mm, 10mm))

57

3.29 Flowchart of the UWB antenna design 58

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3.30 The conventional UWB microstrip antenna with an elliptical shape in

patch (a: front, b: back)

60

3.31 Conventional CPW elliptical UWB antenna 61

3.32 The reflection coefficient result of the antenna after cutting the

ground by staircase

62

3.33 Staircase CPW UWB antenna 63

3.34 the reflection coefficient result of the antenna loaded by a rectangular

ring

64

3.35 The antenna loaded with shorting pin and rectangular ring 65

3.36 Connected stub to the patch 65

3.37 The proposed antenna loaded with shorting pins 66

3.38 The presented UWB antenna in final design (a: front, b: back) 67

3.39 Reflection coefficient result of the conventional UWB elliptical

antenna

68

3.40 Radiation efficiency result of conventional UWB elliptical antenna 68

3.41 3D Radiation pattern of convectional UWB elliptical antenna 69

3.42 2D Radiation pattern of convectional UWB elliptical antenna 70

3.43 Reflection coefficient result of CPW UWB antenna with stair case

GND

71

3.44 Radiation efficiency CPW UWB antenna with stair case GND 71

3.45 3D Radiation pattern of CPW UWB antenna with stair case GND 72

3.46 2D Radiation pattern of CPW UWB antenna with stair case GND 73

3.47 Reflection coefficient result of antenna Loaded with Shorting Pin and

Rectangular Ring

74

3.48 Radiation efficiency result of antenna Loaded with Shorting Pin and

Rectangular Ring

74

3.49 3D Radiation pattern of antenna Loaded with Shorting Pin and

Rectangular Ring

75

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3.50 2D Radiation pattern of antenna Loaded with Shorting Pin and

Rectangular Ring

76

3.51 Comparison between the loading steps 77

3.52 Reflection coefficient of the first three step of design 78

3.53 Radiation efficiency of the first three step of design 78

3.54 Reflection coefficient second three steps of the optimization 79

3.55 3D Radiation pattern three steps of the optimization 80

3.56 2D Radiation pattern three steps of the optimization 80

3.57 The microstrip antenna at 2.4 GHz in final design (a: front view of

first layer, b: ground view of the antenna, c: front view of the second

layer)

81

3.58 Final design of the UWB antenna 81

3.59 Both at the surface 82

3.60 Experimental Setup 83

3.61 Fully submerge in water 84

3.62 One antenna at the surface and the other submerge 84

4.1 Return loss results for both simulation and measurement in air 85

4.2 S-parameters of the proposed rectangular patch cut by three slots as

PBG structure simulated in water

86

4.3 Reflection coefficeint of final design of UWB proposed antenna 87

4.4 3D Radiation pattern final design of proposed antenna 88

4.5 2D Radiation pattern final design of proposed antenna 88

4.6 Measured reflection coefficient result of UWB antenna 89

4.7 Reflection coefficient when one antenna is on the surface and the

other submerged in water

90

4.8 Transmission coefficient when one antenna is surface and the other

one is inserted in water

90

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4.9 S-parameters when one antenna is surface and the other one is

inserted in water

91

4.10 Reflection coefficient results when both of the antennas are inserted

in water

92

4.11 Transmission coefficient results when both antennas are inserted in

water

93

4.12 S-parameters results when both antennas are inserted in water 94

4.13 Reflection coefficient result in terms of Depth variation for 2.4 GHz

microstrip antenna

94

4.14 Transmission coefficient result in terms of Depth variation for 2.4

GHz microstrip antenna

95

4.15 S-parameter result in terms of Depth variation for 2.4 GHz microstrip

antenna (measured after experiment)

95

4.16 Reflection coefficient results when both proposed UWB antenna are

inserted in water

97

4.17 Transmission coefficient results when both of the proposed UWB

antenna are inserted in water

98

4.18 S-parameters results when both the proposed UWB antenna are

inserted in water

98

4.19 Reflection coefficient results when one UWB antenna is at the surface

and the other one in water

99

4.20 Transmission results when one UWB antenna is at the surface and the

other one in water

99

4.21 S-parameters results when one UWB antenna is at the surface and the

other one in water (solid lines show reflection coefficient and dotted

lines transmission coefficient)

100

4.22 Reflection coefficient result in terms of Depth variation for UWB

antenna

101

4.23 Transmission coefficient result in terms of Depth variation for UWB

antenna

101

4.24 S-parameters results in terms of Depth variation for UWB antenna 102

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LIST OF ABBREVIATIONS

SYMBOL DEFINITION

MW Microwave

ISM Industrial, scientific and medical

FCC Federal Communication Commission

LIMR Low-intensity microwave radiation

TL Transmission Line

VSWR Voltage Standing Wave Ratio

AR Axial Ratio

BW Bandwidth

FDTD Finite Difference Time- Domain

Q Quality factor

MSA Microstrip Slot Antennas

PBG Photonic Bandgap

DGS Defected Ground Structure

RFID Radio Frequency Identification

SAW Surface Acoustic Wave

AIA Active Integrated Antenna

MMIC Monolithic Microwave Integrated Circuit

WLAN Wireless Local-Area Network

WiMAX Worldwide Interoperability for Microwave Access

CPW Coplanar Waveguide

UWB Ultra wide band

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CHAPTER 1

1 INTRODUCTION

1.1 Study Background

The communications industry is progressing dynamically towards innovative

thinking and increased creativity, stretching the effort to achieve the impossible and

to go beyond common demands of compactness, high quality and performance, and

economy and cost. As a crucial player in the industry, the antenna requires speedier

advancement to accelerate the industry’s vision of inventing sophisticated appliances

for radar, TV and radio broadcasting, satellite communications, point-to-point

communications, and current wireless communications including underwater

communications and their related devices. Therefore, special attention has been put

on the efficiency of converting electric current to electromagnetic (EM) waves and

vice versa, for which transmitting and receiving signals is given top priority [1].

Underwater communication and localisation systems are receiving huge research

interest due to the role of these systems in exploration and rescue missions, such as

the discovery of natural resources and search operations in the event of plane

crashes. In underwater environments, acoustic systems have many drawbacks such

as long propagation delay, narrow bandwidth, multipath fading, and susceptibility to

propagation characteristics from background media [2]. Moreover, these systems are

broadly utilised for applications that include seaward oil and gas field monitoring,

coastline security and surveillance, as well as oceanographic information gathering,

which will require information return between the two. This is only the tip of the

iceberg of self-sufficient submerged Vehicles (AUVs). Furthermore, submerged

ecological perception is also investigated in this study [3].

1.2 Statement of Problems and Motivations

Due to electromagnetic wave losses in water, the vast majority of remote networks

are now essentially contingent upon sound waves. Therefore, the use of sound waves

is preferred to that of electromagnetic waves [4]; however, scientists are forced to

use many sonic transmitter/receiver systems to cover more areas, so using sound

waves can be costlier than using electromagnetic waves. Thus, current technology is

now relying on electromagnetic waves because of their significant high-speed

propagation, which results in high speed transfer of data. Furthermore, due to the

inflated cost of designing and the maintaining acoustic and optical systems, some

standards for working in microwave (MW) regions such as Wireless Local-Area

Network (WLAN) with the IEEE 802.11 Standard are applied as a reliable solution.

WLAN offers ease of use throughout the world and rather low cost, but it also

requires working knowledge and experience. Another free band, which is unlicensed

and free, is the Industrial, Scientific and Medical (ISM) band. ISM can contribute to

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bringing down the cost of WLAN. Moreover, the ISM frequency band is now being

used rapidly, especially in low-power and short distance communications.

Nowadays, the greater part of researchers’ focus is on enhancing the distances between the nodes, whilst achieving a high BW network with high data rate

transitions [5]. Furthermore, underwater propagation methods such as optical,

electromagnetic, acoustic or ultrasonic signals have some advantages and

disadvantages, as illustrated in [3]. However, optical signals might still propagate

exceptionally. Ocean water comprises particles that diffuse these signals. Thus, the

optical method is not reliable over long distances. Acoustic signals are not as

susceptible to sea particles in comparison with optical signals. This is because its

signal capability is dependent upon 20-km distances, so it can be utilised broadly.

Electromagnetic signals over very short distances can promise higher data rates of up

to 10 Mbps. EM waves are highly dependent on the material characteristics

(permittivity) of the environment around the sensor networks [6]. On the other hand,

underwater communication is not only limited to communication within the

underwater environment itself but might also involve communication paths that

cross the air-water boundary. Besides that, when only underwater communication is

required, sonic systems cannot be used due to their being too bulky and costly. Thus,

for other types of communication other than underwater communications such as

trans-air-to-water underwater communication, electromagnetic waves are the best

choice, since these waves are not adversely affected by the air-water boundary, and

could even be either air-seawater or air-freshwater interfaces.

The above are examples of problems that researchers face while using frequency

ranges other than MW, as transmitters/receivers should have a broad BW to cover

more frequency bands. Thus, wide bands and ultra-wide band (UWB) systems are

seen as promising devices. The recent narrow-band [76-80] antennas with lower gain

and bigger size showed complicated structure while the photonic band gab (PBG)

structure could be promising to compensate those drawbacks. Besides, wide-band

and ultra-wideband antennas [81-86] with less working BW, lower gain along with

larger dimensions compared to the operating frequency for underwater

communications have demonstrated more complicated design in terms of patch

shape since the elliptical shape patch is one of simplest shape can be consider for

UWB antennas.. Besides that, similar works on antennas for underwater

communications have proposed designs that are very complicated and difficult to

fabricate besides being heavy and bulky.

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1.3 Objectives of study

The primary goal of this study is to design a high gain compact antenna for

underwater communications followed with an analysis of the antenna characteristics.

1. To design a narrowband compact microstrip antenna with high gain at a single

operating frequency of 2.4 GHz 2. To design a high gain compact ultra-wide band antenna 3. To investigate the performance of the designed antennas for underwater

applications

1.4 Study Scope

The scope of this study is to simulate and design two antennas with different

frequency bandwidths (BW) for underwater communications. The first one is a

microstrip antenna with high performance at 2.4 GHz while the second is a UWB

antenna. Figure 1.1 outlines the scope of this study in more detail. In reference to

Figure 1.1, the solid lines depict the directions followed in this study to obtain the

research objectives, while the dashed-lines indicate the other research areas that are

covered in this work.

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Figure 1.1 : Study scope

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1.5 Research Methodology

At 2.4 GHz, the narrowband antenna is designed on an RT/Duroid 5880 substrate

with a permittivity of 2.2 and thickness of 0.787 mm, so as to lower permittivity and

increase the BW and radiation efficiency. The design processes are presented as

follows: firstly, a rectangular patch is designed to resonate at 2.4 GHz according to

the transmission line theory, which is = 41.5 mm [7]. For the initial calculations

to obtain the actual antenna dimensions, the transmission line technique [8] for the

rectangular patch was used. Then, three periodic rectangular photonic band gap

structures are etched from the rectangular patch. These rectangular slots have the

same width ( ), which is the period of our PBG structure. Moreover, the length of

these slots decreases periodically and follows a pattern of a filling factor of the PBG

structure. A PBG structure is required to decrease surface waves, which is a serious

problem for the microstrip antenna. Surface waves are excited on microstrip

antennas whenever the substrate permittivity >1 [9]. Apart from the end-fire

radiation, surface waves have some undesirable features such as edge diffraction,

and spurious coupling between different antenna elements. Besides that, surface

waves reduce antenna efficiency and gain, limit the BW, increase the end-fire

radiation, and increase the cross-polarisation level. In the next step, a small

rectangular slot is cut from the ground layer located next to the feed line. This slot is

used for suppressing the back radiation from the antenna [10]. This shows that the

current density on the edge of the patch has been reduced and distributed to its centre

by PBG.

Next, the second layer is added to the first one with a 1.71 mm thick air layer in

between. This air layer is required to increase the efficiency and the gain of the

antenna. Increasing air layer thickness augments resonant frequency. Two cross

elliptical rings are subtended on the second layer as the second resonator to improve

antenna performance. This layer’s substrate is called the Rogers 3210 with a

permittivity of 10.2 and a thickness of 1.28 mm. Eventually, two layers of RT/Droid

5880 with a thickness of 3.15 mm are used to cover the second layer stack antenna.

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Figure 1.2 : Methodology flowchart Last but not least, two proposed antennas were exploited in water with a permittivity

of 78 and maintaining the same size (after checking the results, the water dimensions

increased by 10 mm) and then the distances enhanced. Afterward, the antenna

radiation characteristics were investigated within a distance range of 15 to 45 mm

based on the wavelength changes and impacts of the medium (air and water) and

certain materials (normal water). Hence, the wavelength restrictions in these two

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mediums—air and normal water—should be around , which are almost 31 mm

and 3.5 mm, respectively.

To design the second antenna, the same principles, equations, and feeding technique

apply for obtaining the first dimensions of the antenna. An elliptical shape was used

as a patch because of its simplicity in design and fabrication. Thereafter, some

techniques are exploited to increase the BW and the characteristics of the antenna,

for example, radiation efficiency. In the design process, it is best to keep the antenna

small even at a lower frequency band.

1.6 Thesis Configuration

This study consists of five chapters, with the details of each summarised below:

Chapter 1 presents the research area, and identifies the present issues in planning

microstrip antennas to investigate advances in the field. It also presents the research

goal, objectives, methodology, scope for exploration, and antenna proposal in this

study.

Chapter 2 outlines the literature review on remote correspondence applications,

microstrip radio wire outlining procedures, as well as UWB antennas. The principle

theories and historical background of microstrip antennas are also discussed.

Secondly, UWB radio wire shapes and their provisions are described. Then, the

strategies on expanding the design of microstrip antennas are explored. Finally, this

chapter is concluded in the summary section.

Chapter 3 first shows a new design of the microstrip antenna at 2.4 GHz as well as

their geometric parameters, and discusses the constitutive effective parameters

retrieved from the transmission and reflection coefficients in each step of the design.

After obtaining the results from the first antenna, a new simulation structure of the

UWB antenna is provided for testing and validation in underwater communications.

Both antennas are designed in air first and then simulated in water. Finally, after

fabrication and measurement in both water and air, their results are compared.

Chapter 4 discusses the complete results for both the PBG rectangular stack antenna

and the proposed elliptical UWB antenna. First, the simulation results of these

antennas are presented in air and then their medium is changed to water. Finally,

their fabrication results are compared with the simulation results in both mediums—air and water.

In Chapter 5, the entire study is summarised and concluded and then followed with

the major contributions of the study. Eventually, potential ideas for future work are

suggested.

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6 REFERENCES

[1] R. M. Walser, (2003). Metamaterials: an introduction Introduction to Complex

Mediums for Optics and Electromagnetics. Bellingham, WA: SPIE Press.

[2] J Pendry, Holden, A., Robbins, D., & Stewart, W. (1999). Magnetism from

conductors and enhanced nonlinear phenomena. IEEE Transactions on

Microwave Theory and Techniques, 47(11), 2075–2084.

[3] D. Smith, Padilla, W. J., Vier, D., Nemat-Nasser, S. C., & Schultz, S. (2000).

Composite medium with simultaneously negative permeability and

permittivity. Physical Review Letters, 84(18), 4184–4187.

[4] C. P. Dargie, Fundamentals of Wireless Sensor Networks: Theory and

Practice, John Wiley and Sons.

[5] S. G. Jiang, “Electromagnetic wave propagation into fresh water,” J. Electromagn. Anal. Appl., vol. 3, pp. 261–266, 2011.

[6] A. K. Hunt and K., J. Niemeier, “RF communications in underwater wireless sensor networks,” IEEE Int. Conf. Electro/Information Technol. (EIT), 2010.

[7] T. M. Stuntebeck and, E., D. Pompili, “Wireless under-ground sensor networks

using commodity terrestrial motes,” 2nd IEEE Work. Wirel. Mesh Networks, 2006.

[8] X Che,., I. and M. R.Wells, P. Kear, G. Dickers, X. Gong, “A static multi-hop

underwater wireless sensor network using RF electromagnetic

communications,” 29th IEEE Int. Conf. Distrib. Comput. Syst. Canada, 2009.

[9] E. A. Karagianni, “Electromagnetic Waves under Sea : Bow-Tie Antenna

Design for Wi-Fi Underwater Communications,” vol. 41, no. January, pp. 189–198, 2015.

[10] K., Y. Kumar and S. Singh, “A modified bow tie antenna with U-shape slot

for wireless applications,” Int. J. Emerg. Technol. Adv. Eng., vol. 2, no. 10, 2012.

[11] E. Ekmekci, & G. Turhan-Sayan, (2009). A novel dual-band metamaterial

structure. Progress in Electromagnetics Research Symposium Proceedings,

Moscow, Russia, August 18-21, 87–90.

[12] X. Zhou, Y. Liu, , & Zhao, X. (2009). Low losses left-handed materials with

optimized electric and magnetic resonance. Applied Physics A: Materials

Science & Processing, 98(3), 643–649.

© COPYRIG

HT UPM

107

[13] C Zhu, Ma, J. J., Chen, L., & Liang, C. H. (2009). Negative index

metamaterials composed of triangular open-loop resonator and wire structures.

Microwave and Optical Technology Letters, 51(9), 2022–2025.

[14] J.Zhu, , & Eleftheriades, G. V. (2009). A compact transmission-line

metamaterial antenna with extended bandwidth. IEEE Antennas and Wireless

Propagation Letters, 8, 295–298.

[15] H. A.Majid, , M. K. A.Rahim, , & T. Masri, (2009). Microstrip antenna's gain

enhancement using left-handed metamaterial structure. Progress in

Electromagnetics Research, 8, 235–247.

[16] B. Zhou, & T. J. Cui, (2011). Directivity enhancement to Vivaldi antennas

using compactly anisotropic zero-index metamaterials. IEEE Antennas and

Wireless Propagation Letters, 10, 326–329.

[17] B.Zhou, , H.Li, , X.Zou, , & Cui, T. J. (2011). Broadband and high-gain planar

Vivaldi antennas based on inhomogeneous anisotropic zero-index

metamaterials. Progress in Electromagnetics Research, 120, 235–247.

[18] P. Mathur, “Miniaturization and Feeding Techniques of H-Shaped Antenna,” no. 6, pp. 978–981, 2012.

[19] I. J. Bahl, Lumped Elements for RF and Microwave Circuits. London: Artech

House, 2003.

[20] M.David Pozar, “Microwave Engineering,” Addison-Wesley Publ. Co., 1993.

[21] D. John Kraus, antennas and wave propagation, 4th ed.

[22] C. Fung, “Basic Antenna Theory and Application,” 2011.

[23] Dean A. Frickey “Conversions Between S, Z, Y, h, ABCD, and T Parameters

Which are Valid for Complex Source and Load Impedances,” IEEE Trans.

Microw. Theory Tech.,, vol. 42, no. 2, pp. 205–211, 1994.

[24] Deschamps,G.A, “Microstrip Microwave Antennas,” 1953.

[25] J. Howell, “Microstrip Antennas,” IEEE AP-S Int, pp. 177–180, 1971.

[26] C. Gupta K, “Microstrip Lines and Slot Lines,” Artech House, Norwood,MA,

1996.

[27] P. B. Ramesh Garg, Microstrip Antenna Design Handbook. 2000.

[28] D. M. Pozar, “Considrations for Milimeter Wave Printed Antennas,” IEEE

Trans. Antennas Propag., pp. 740–747, 1983.

© COPYRIG

HT UPM

108

[29] D. M. Pozar, “Considrations for Milimeter Wave Printed Antennas,” IEEE Trans. Antennas Propag., pp. 740–747, 1983.

[30] K. . and E. . C. Carver, “Theoritical Investigation of the Microstrip Antenna,” Phys. Sci. Lab. New Mex. State Univ. las Cruces, 1979.

[31] Z. N. Chen, Broadband Planar Antennas: Design and Applications.

[32] V. Bernard, J. Paul, and I. Iloh, “Microstrip Antenna Design Using Transmission Line Model,” vol. 3, no. 11, 2013.

[33] K. Moussakhani and A. Ghorbani, “A Novel Transmission Line Model for Analyzing Bowtie Patch Antennas,” pp. 168–171, 2006.

[34] Y. H. Richards W.F., “An Improved Theory for Microstrip Antennas and Applications,” IEEE Trans. Antennas Propag., pp. 38–46, 1981.

[35] Z. Hua and S. Hu, “Antennas with Frequency Domain Control for Future

Communication,” University of Birmingham, 2012.

[36] K. Kirschning, M, R. Jansen and N, “Accurate Model for Open-end Effect of

Microstrip Line,” Electron. Lett, vol. 17, pp. 123–125, 1981.

[37] V. Bernard, J. Paul, and I. Iloh, “Microstrip Antenna Design Using Transmission Line Model,” vol. 3, no. 11, 2013.

[38] Z. Hua and S. Hu, “Antennas with Frequency Domain Control for Future Communication,” University of Birmingham, 2012..

[39] Christophe Caloz and Tatsuo Itoh, "Electromagnetic Metammaterials". Wiley,

2005.

[32] Y.J. Zhang J. F. Y. S. Hu,“Equivalent Circuit Model of Coaxial Probes,” vol. 38, no. February, pp. 281–296, 2012.

[40] A. Kumar, J. Kaur, and R. Singh, “Performance Analysis of Different Feeding Techniques,” vol. 3, no. 3, pp. 884–890, 2013.

[41] A. Majumder, “Rectangular Microstrip Patch Antenna Using Coaxial Probe Feeding Technique to Operate in S-Band,” vol. 4, no. April, pp. 1206–1210,

2013.

[42] M. Ahamed and K. Bhowmik, “Rectangular Microstrip Patch Antenna at 2GHZ on Different Dielectric Constant for Pervasive Wireless

Communication,” vol. 2, no. 3, pp. 417–424, 2012.

[43] M. Habibullah, M. T. Islam, M. R. Ahsan, J. S. Mandeep, and N. Misran, “A Dual Band Slotted Patch Antenna on Dielectric Material Substrate,” Int. J.

Antennas Propag., vol. 2014, pp. 1–7, 2014.

© COPYRIG

HT UPM

109

[44] B. K. Gupta and S. Mishra, “Analysis of Circular Disc Antenna Using Defective Ground Plane,” pp. 2319–2321, 2014.

[45] K. P. Raju, “Circular Disk Monopole Antenna for Broadband,” vol. 2, no. 6, pp. 3–6, 2012.

[46] M. Samsuzzaman, M. T. Islam, J. S. Mandeep, and N. Misran, “Printed Wide-

slot Antenna Design with Bandwidth and Gain Enhancement on Low-cost

Substrate.,” ScientificWorldJournal., vol. 2014, p. 804068, Jan. 2014.

[47] M. T. Islam, N. Misran, and J. S. M. J. J. Tiang, “Progress In Electromagnetics Research, Vol. 120, 499–512, 2011,” vol. 120, no. September, pp. 499–512,

2011.

[48] Y. Qian, T. Itoh, and L. Fellow, “Broad-Band Power Amplifier Using,” vol. 8, no. 1, pp. 1997–1998, 1998.

[49] Ghavami N., G. Tiberi, D. J. Edwards, and A. M. (2012). UWB Microwave

Imaging of Objects With Canonical Shape. Antennas and Propagation, IEEE

Transactions on, 60, 231–239.

[50] Y. X. Sun, K. W. Leung, and A. D. D. C. Dra, “Dual-Band and Wideband

Dual-Polarized Cylindrical Dielectric Resonator Antennas,” vol. 12, pp. 384–387, 2013.

[51] M. F. Ain, Y. M. Qasaymeh, Z. A. Ahmad, M. A. Zakariya, and U. Ullah, “An Equivalent Circuit of Microstrip Slot Coupled Rectangular Dielectric

Resonator Antenna,” pp. 1837–1840, 2012.

[52] R. Waterhouse, “Printed Antennas for Wireless Communications,” John Wiley

Sons Inc, 2007.

[53] Sharma, V., Saxena, V. K., & Sharma, K. B. (2011). Radiation Performance of

an Elliptical Patch Antenna with Three Orthogonal, 14(2), 123–130.

[54] Balanis, C. A. (2009). Antenna Theory: Analysis and Design, (3RD ED.).

Wiley India Pvt. Limited.

[55] Y. X. Sun, K. W. Leung, and A. D. D. C. Dra, “Dual-Band and Wideband

Dual-Polarized Cylindrical Dielectric Resonator Antennas,” vol. 12, pp. 384–387, 2013.

[56] M. F. Ain, Y. M. Qasaymeh, Z. A. Ahmad, M. A. Zakariya, and U. Ullah, “An Equivalent Circuit of Microstrip Slot Coupled Rectangular Dielectric

Resonator Antenna,” pp. 1837–1840, 2012.

[57] R. Waterhouse, “Printed Antennas for Wireless Communications,” John Wiley Sons Inc, 2007.

© COPYRIG

HT UPM

110

[58] D. M. Pozar, “Considrations for Milimeter Wave Printed Antennas,” IEEE Trans. Antennas Propag., pp. 740–747, 1983.

[59] S. Raje, S. Kazemi, and H. R. Hassani, “Wideband Stacked Koch Fractal Antenna With H-Shape Aperture Coupled Feed,” 2007 Asia-Pacific Microw. Conf., pp. 1–4, Dec. 2007.

[60] R. S. Aziz, M. A. S. Alkanhal, and A. F. A. Sheta, “Triple Band Fractal-Like

Antennas,” pp. 886–889, 2011.

[61] “CST Microwave Studio.” 2013.

[62] T.Peter, M.K.A. Rahim, J.Din, T.Masri, “Active Integrated Antenna with Low Noise Amplifier Design at 5 GHz,” vol. 5780, pp. 5–10.

[63] C. A. Balanis, Antenna Theory Analysis and Design, 2 ed. New York: Wiley,

1997.

[64] R. E. Collin, "Foundations for Microwave Engineering", 2 ed. New York:

McGraw-Hill, 1996.

[65] M. L. Filters, N. C. Karmakar, S. Member, and M. N. Mollah, “Investigations Into Nonuniform Photonic-Bandgap,” vol. 51, no. 2, pp. 564–572, 2003.

[66] Roberto Coccioli, “Aperture-Coupled Patch Antenna,” IEEE Trans. Microw. Theory Tech., vol. 47, no. 11, pp. 2123–2130, 1999.

[67] D. M. POZAR, “Microstrip Antenna Aperture-Coupled to a Microstrip line

Fault Detection and Identification for Reliable Large-Scale Computing,” Electron. Lett., vol. 21, pp. 49–50, 1985.

[68] Zurcher, J. F., and F. E. G. “Broadband Patch Antennas,” Artech House, Norwood, MA, 1995.

[69] M. El Yazidi, M. Himdi and J. P. D., “Transmission line analysis of nonlinear slot coupled microstrip antenna,” Electron. Lett., vol. 28, no. 15, pp. 1406–1408, 1992.

[70] Ghavami N., G. Tiberi, D. J. Edwards, and A. M. (2012). UWB Microwave

Imaging of Objects With Canonical Shape. Antennas and Propagation, IEEE

Transactions on, 60, 231–239.

[71] Sharma, V., Saxena, V. K., & Sharma, K. B. (2011). Radiation Performance of

an Elliptical Patch Antenna with Three Orthogonal, 14(2), 123–130.

[72] Sachin Kumar, “Design and Comparison of Modified Circular Bow-Tie

Antenna for Under Water Radio Communication by Optimizing Different

Parameters”, Thapar University India, June 2012.

© COPYRIG

HT UPM

111

[73] Nisha George, Ganesan R., Dinakardas C. N, “Design of Wide Band Antenna

for Ocean Communication: Review”, International Journal of Advanced

Computer Research, March 2014.

[74] Brian Kelley, Krishna Naishadham, “RF Multicarrier Signaling and Antenna Systems for SNR Broadband Underwater Communications”, IEEE BioWireless, 987, 1, 2013.

[75] Amitt, Sandip Vijay and Manish Kumar Pandey, “Antenna Design for Underwater Communication (Wide band): A Review”, IJCTA, 10 (9), pp.33-

41, 2017.

[76] L. Chang, H. Wang, Z. Zhang, Y. Li, and Z. Feng, “A Dual - Environment

Active RFID Tag Antenna Mountable on Metallic Objects,” vol. 1225, no. c, 2016.

[77] C. Lin and J. Sun, “Circularly Polarized Dielectric Resonator Antenna,” vol. 14, pp. 2014–2016, 2015.

[78] R. A. Firdaus, Y. H. Pramono, E. Yahya, and W. H. Gunawan, “Design of a Compact Antenna with Stub using Stepped Impedance Resonator,” vol. 2, no. 1, pp. 6–9, 2015.

[79] A. Sarma, “Low Return Loss Slotted Rectangular Microstrip Patch Antenna at

2 . 4 GHz,” pp. 35–39, 2015.

[80] A. K. Sharma, A. Mittal, and B. V. R. Reddy, “Slot embedded dual-band

patch antenna for WLAN and WiMAX applications,” vol. 51, no. 8, pp. 608–609, 2015.

[81] Aleix Garcia Miquel, “UWB Antenna Design For Underwater

Communications”, Delf University of Technlogy, 25th May 2009.

[82] C. A. Balanis, (2009). Antenna Theory: Analysis and Design, (3RD ED.).

Wiley India Pvt. Limited.

[83] D. M . Pozar. (2011). Microwave Engineering (4th Editio.). Wiley Global

Education.

[84] M. Ifwat Mohd Ghazali, K. Y. Park, J. A. Byford, J. Papapolymerou, and P.

Chahal, “3D Printed Metalized-Polymer UWB High-Gain Vivaldi Antennas”, IEEE 2016.

[85] M. N. Shakib, M. Moghavvemi, and W. N. L. Mahadi, “Design of a Compact

Planar Antenna for Ultra-wideband Operation”, ACES Journal, Vol. 30, No. 2, 2015.

[86] R. Yahya, M. R. Kamarudin, N. Seman, H. U. Iddi, “Eye Shaped Fabric Antenna for UWB Application”, AP-S IEEE, 2013.