PLANAR MONOPOLE ANTENNAS WITH REFLECTION PLANE FOR HUMAN BODY CENTRIC COMMUNICATION EBRAHIM SAILAN GUBRAN ALABIDI A thesis submitted in fulfilment of the requirements for the award of the degree of Doctor of Philosophy (Electrical Engineering) Faculty of Electrical Engineering Universiti Teknologi Malaysia JANUARY 2015
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PLANAR MONOPOLE ANTENNAS WITH REFLECTION PLANE FOR
HUMAN BODY CENTRIC COMMUNICATION
EBRAHIM SAILAN GUBRAN ALABIDI
A thesis submitted in fulfilment o f the
requirements for the award o f the degree o f
Doctor o f Philosophy (Electrical Engineering)
Faculty o f Electrical Engineering
Universiti Teknologi Malaysia
JANUARY 2015
To my beloved mother and father
To my wife
And my friends
ACKNOW LEDGEM ENT
In preparing this project report, I was in contact with many people,
researchers, academicians, and practitioners. They have contributed towards my
understanding and thoughts. In particular, I wish to express my sincere appreciation
to my main project report supervisor, Assoc. Prof. Dr. Muhammad Ramlee Bin
Kamarudin.for his encouragement, guidance, critics, and motivation. Without his
continued support and interest, this project report would not have been the same as
presented here.
I would like to thank Prof. Tharek Bin Abd Rahman and staff in Wireless
Communication Center (WCC) for their help, facilities and for providing conducive
working environment.
Finally, I am deeply and forever indebted to my wife, parents for their love,
spiritual support, and encouragement throughout my entire life.
ABSTRACT
Wireless Body Area Network (WBAN) is an emerging technology that requires an antenna to be placed on human body for a wide range o f applications such as healthcare, entertainment, surveillance, emergency and military. The reflection coefficient magnitude o f the antenna in closeness to the human body is degraded and shifted. Essentially, efficiency and gain reduction are the main disadvantages o f the antenna performances due to the body effect. In this research, methods o f improving efficiency, gain, Specific Absorption Rate (SAR) and stabilizing reflection coefficient magnitude have been proposed. In this work, the design, simulation and fabrication o f two monopole antennas with P-shaped and circular-shaped are presented. The proposed P-shaped monopole antenna is designed to operate from 3.1 to 5.1 GHz while the proposed circular-shaped monopole antenna operates at 3.1-5.1 GHz and 6.5-8 GHz. The simulation o f the proposed antennas in free space and close proximity o f body surface has been carried out using Computer Simulation Technology (CST) Microwave Studio. It has been found that when the P-shaped and circular elements are introduced to the ground plane o f the antennas, the reflection coefficient magnitudes with the presence o f body for both antennas remain the same as in free space. Moreover, the efficiency and gain of the antennas have been improved by attaching the glass substrate to the ground plane. P-shaped antenna with the glass substrate has demonstrated about 34.6%, 35% and 39.2% improvement o f the antenna efficiency at 3.3, 4.45 and 5 GHz, respectively, when placed directly on the human head. For the human chest placement, the antenna demonstrates 30.7%, 33.4% and 36%, and the gain o f 3.4, 2.8 and 4 dBi o f antenna efficiency and gain improvement at 3.3, 4.45 and 5 GHz, respectively. Similarly, for circular-shaped monopole antenna the improvement of the antenna efficiency obtained for human head are 39.8% and 37.23% at 3.3 and 7.5 GHz, respectively, and for the chest are 36.5% and 32.8% at 3.3 and 7.5 GHz, accordingly. The antenna demonstrates 2.9 and 2.54 dBi improvement o f the gain at3.3 and 7.5 GHz, respectively. These improvements are compared with the antenna without the glass substrate. This study concludes that the glass substrate has improved the gain, efficiency and SAR when placed near human body compared to other antennas and the Sn remains stable when some additional elements are introduced to the ground plane. It was observed that there is good agreement between the simulation and measurement results, thereby showing that the antennas have potential to be deployed for W BAN application.
ABSTRAK
Rangkaian Kawasan Badan Tanpa Wayar (WBAN) adalah sebuah teknologi baru yang memerlukan antena diletakkan pada badan manusia untuk pelbagai aplikasi seperti penjagaan kesihatan, hiburan, pengawasan, kecemasan dan ketenteraan. Magnitud bagi pekali pantulan antena yang berdekatan dengan tubuh badan manusia adalah berkurangan dan berubah. Pada asasnya, kecekapan dan pengurangan gandaan adalah kelemahan utama ke atas keupayaan antena disebabkan oleh kesan badan. Dalam kerja penyelidikan ini, kaedah-kaedah bagi meningkatkan kecekapan, gandaan, Kadar Penyerapan Tertentu (SAR) dan penstabilan magnitud pekali pantulan telah dicadangkan. Dalam kajian ini, reka bentuk, simulasi dan fabrikasi antena ekakutub berbentuk P dan bulat telah dibentangkan. Antena ekakutub berbentuk P yang dicadangkan adalah direka bentuk untuk beroperasi daripada 3.1 ke 5.1 GHz manakala antena ekakutub berbentuk bulat dicadangkan bagi operasi dua jalur iaitu 3.1-5.1 GHz dan 6.5-8 GHz. Simulasi antena di ruang bebas dan ketika diletakkan pada permukaan badan telah dijalankan menggunakan Teknologi Simulasi Komputer (CST) Studio Gelombang Mikro. lanya telah didapati bahawa, apabila elemen bentuk P dan bulat diperkenalkan ke atas satah bumi, pekali pantulan dengan kehadiran badan manusia bagi kedua-dua antena adalah kekal sama seperti yang terhasil pada ruang bebas. Selain itu, keberkesanan gandaan pada antena diperbaiki dengan menggandingkan substrat kaca ke atas satah bumi. Antena berbentuk P dengan substrat kaca telah menunjukkan peningkatan terhadap kecekapan sebanyak 34.6%, 35% dan 39.2% pada 3.3, 4.45 dan 5 GHz apabila diletakkan berhampiran dengan kepala manusia. Manakala, apabila antena diletakkan pada dada manusia, peningkatan kecekapan yang diperoleh adalah 30.7%, 33.4% dan 36% dan gandaan pula memberikan peningkatan sebanyak 3.4,2.8 dan 4 dBi pada 3.3, 4.45 dan 5 GHz. Kecekapan yang berjaya diperolehi apabila antena diletakkan pada bahagian kepala ialah 39.8% dan 37.23% pada 3.3 GHz dan7.5 GHz. Bagi bahagian dada manusia pula pula 36.5% dan 32.8% pada 3.3 dan 7.5 GHz. Antena ini juga menunjukkan peningkatan gandaan sebanyak 2.9 dan 2.54 dBi pada frekuensi 3.3 dan 7.5 GHz. Peningkatan ini telah dibandingkan dengan antena tanpa substrat kaca. Kajian ini menyimpulkan bahawa substrat kaca telah meningkatkan gandaan, kecekapan dan memperbaiki nilai SAR apabila diletakkan berhampiran badan manusia berbanding antena lain, dan S11 kekal stabil apabila sebahagian elemen tambahan diperkenalkan pada satah bumi. Dapat diperhatikan bahawa terdapat perhubungan yang baik antara simulasi dan keputusan pengukuran, sekaligus menunjukkan bahawa antena mempunyai potensi untuk digunakan untuk aplikasi WBAN.
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOW LEDGEM ENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF ABBREVIATIONS xvi
LIST OF SYMBOLS xvii
LIST OF APPENDICES xviii
1 INTRODUCTION 1
1.1 Introduction 1
1.2 Problem Statement 2
1.3 Research Objectives 3
1.4 Scope of the Research 4
1.5 Contribution of the Research 5
1.6 Organization of the thesis 6
2 LITERATURE REVIEW 8
2.1 Introduction 8
2.2 The Standardization of (WBAN) 9
2.3 UWB Technology 12
2.4 Ultra Wideband vs. Narrowband Antenna Parameters 14
2.5 The Specific Absorption Rate (SAR) 16
2.6 The Radiation Efficiency Antenna 17
2.7 Electromagnetic Properties and Modeling of the Human Body 19
2.8 Reviews on Antenna Design 26
2.9 The Reflection Plane Between the Antenna and the Human Body 39
2.10 Summary 43
3 M ETHODOLOGY 44
3.1 Introduction 44
3.2 Simulation Software 47
3.3 Solver 48
3.4 Parameter Specifications 49
3.5 Modeling of the Human Body 50
3.6 Calculations for the Specific Absorption Rate 51
3.7 Antenna Design with Reflection Plane Technique 53
3.8 Measurement Procedures for Antenna 54
3.9 Dielectric Constant Measurement 59
4.0 Summary 61
4 P-SHAPED MONOPOLE ANTENNA DESIGN 61
4.1 Introduction 61
4.2 Antenna Design 63
4.3 Parametric Studies for the Proposed P-Shaped Monopole Antenna 69
4.4 Modelling of the Human Body 72
4.5 Results and Discussion 73
4.6 Summary 79
5 RADIATION CHARACTERISTICS IM PROVEM ENT OF MONOPOLE ANTENNA ABOVE GLASS SUBSTRATE 80
5.1 Introduction 80
5.2 Reflection Plane 81
5.3 Modelling of the Human Body 95
5.4 Design and Analysis 97
5.5 Experimental V erification of Results 107
5.6 Comparison this Research with Other Work 113
5.7 Summary 115
6 DUAL BAND M ONOPOLE ANTENNA DESIGN 116
6.1 Introduction 116
6.2 Antenna Design 117
6.3 Parametric Studies for the Proposed Circular-Shaped Antenna 123
6.4 Results and Discussion 126
6.5 Comparison this Research with Other Work 135
6.6 Summary 137
7 CONCLUSION AND FUTURE W ORK 138
7.1 Conclusion 138
7.2 Future Work 140
REFERENCES
Appendix A
142
155
TABLE NO. TITLE PAGE
2.1 Lists the features o f the available technologies for W BAN 11
2.2 A comparison between UWB and narrowband antenna
parameters for W BAN communications 14
2.3 Comparison o f size and volume o f the ultra-wideband antennas
used in this section 33
3.1 Parameter specifications for substrates 49
3.2 Electrical properties o f human body tissues at 3, 4 and 5 GH 51
3.3 The Parameters o f the Human Body Model 51
3.4 Skin Depth calculation 52
4.1 The optimzed parameters o f the P-shaped monopole antenna 64
4.2 The improved characteristics o f the proposed antenna with and
without P-shaped in the ground plane 70
5.1 The parameters o f the human body model 95
5.2 The parameters o f the designed printed PSMA 98
5.3 The proposed antenna with reflection planes for radiation
efficiency, gain and SAR when at Gth=0.5mm, 1mm and 2mm 108
5.4 A Comparison o f ansoft HFSS and CST microwave studio
simulation software 112
5.5 Comparison this research with other work 113
6.1 Comparison between SMA on the left and right side results of
the proposed antenna 121
6.2 Comparison this research with other work 135
FIGURE NO. TITLE PAGE
1.1 Envisioned W BAN in Healthcare Applications 2
1.2 The scope of this research 5
2.1 Envisioned W BAN and its possible components 9
2.2 WBAN applications at ISM and UWB 13
2.3 Resonator model for an antenna 18
2.4 Measured data o f human tissue permittivity for various types 21
2.5 Measured data o f human tissue conductivity for various types 21
2.6 Voxel family o f the digital phantoms (Donna) 23
2.7 The arm a probe to measure the radiated energy 26
2.8 The antenna gain o f the proposed UWB antenna a) The gain in
the free space b) The gain near to the human body 27
2.9 UWB antenna operation frequency at (3.1-5.1) GHz 28
2.10 The diamond antenna 28
2.11 The L-shaped antenna 29
2.12 The gain o f the proposed antenna in free space and close the
human body 29
2.13 The antenna gain o f the proposed antenna 30
2.14 Geometry and dimensions o f the proposed antenna 31
2.15 Geometry and dimensions o f the proposed antenna 32
2.16 Geometry and dimensions o f the proposed antenna 32
2.17 Geometry and dimensions o f the proposed antenna 33
2.18 Reflection coefficient magnitude o f the four proposed antennas
when placed o f the chest human 36
2.19 Comparison o f on-body radiation efficiency in percentage for
four different UWB antennas when placed close the body 38
2.20 The reflection plane o f a one layer substrate RH-5 40
2.21 The Electromagnetic Band Gap substrate 40
2.22 A perfect electric conduction copper substrate 41
2.23 The glass substrate as the reflection plane 41
3.1 The summary o f the work schedule 45
3.2 The flow chart o f the work schedule 46
3.3 CST Microwave Studio 2012 user interface window 48
3.4 Three layers o f chest wall used in electromagnetic simulation 50
3.5 Side view o f the reflection plane with the antenna placed close
the human body 54
3.6 Network Analyzer 54
3.7 Anechoic chambers 55
3.8 Antenna under measurement by Vector Network Analyzer 56
3.9 The antenna rotated in the horizontal plane with some degree 57
3.10 The radiation pattern graph for antennas 58
3.11 Measurement dielectric constant for glass substrate 60
3.12 Loss tangent vector diagram 60
4.1 The proposed P-shaped monopole antenna geometry 64
4.2 Prototype o f the proposed P-shaped monopole antenna
(a) Front view (b) Back view 65
4.3 Physical and effective lengths o f the patch antenna 65
4.4 The simulated current distribution for the proposed
P-shape monopole antenna 68
4.5 The proposed antenna (a) With P-shaped element on the ground
plane (b) Without a P shaped element at the ground plane 69
4.6 The simulated results o f the reflection coefficient, S11 70
4.7 Comparison o f the reflection coefficient magnitude S11
for different values o f G 72
4.8 The simulation o f the three layers o f chest human body 72
4.9 The distance between antenna and body is represented by d 73
4.10 Measured and the simulated S 11 results o f the proposed
antenna in free space 74
4.11 The comparison o f the S 11 o f the proposed antenna when
placed 4 mm away from the body 75
4.12 Measured and simulated radiation pattern o f the proposed
antenna when placed 4 mm away from the body 77
4.13 The comparison o f proposed antenna efficiency antenna
when placed 4 mm away from the body 78
5.1 The best reflection plane substrate 80
5.2 The shapes o f the reflection plane elements (copper
or glass substrate) 82
5.3 Back view o f the proposed antenna 83
5.4 The rectangular-shaped o f glass or PEC substrate when attached to
the PSMA 83
5.5 The simulated results o f the reflection coefficient magnitude 84
5.6 The simulated results o f the antenna efficiency 84
5.7 The rectangular-shaped o f glass or copper substrate when
attached to the PSMA 85
5.8 The simulated results o f the reflection coefficient magnitude 86
5.9 The simulated results o f the antenna efficiency 86
5.10 The rectangular-shaped o f glass or copper substrate when
attached to the PSMA 87
5.11 The simulated results o f the reflection coefficient magnitude 88
5.12 The simulated results o f the antenna efficiency 88
5.13 The circular-shaped o f glass or copper substrate when attached
to the PSMA 89
5.14 The simulated results o f the reflection coefficient magnitude 90
5.15 The simulated results o f the antenna efficiency 90
5.16 The U-shaped o f copper or glass reflection plane when
attached to the PSMA 91
5.17 The simulated results o f the reflection coefficient magnitude 92
5.18 The simulated results o f the antenna efficiency 92
5.19 The proposed antenna with L-shaped reflection plane
o f copper or glass substrate simulation 93
5.20 The simulated results o f the reflection coefficient magnitude 94
5.21 The simulated results o f the antenna efficiency 94
5.22 The measurement o f the proposed antenna with a glass
substrate close to the chest human body 96
5.23 The measurement o f the proposed antenna with a glass
substrate close to the head human body 96
5.24 The proposed P-shaped monopole antenna with glass
reflection plane (a) Front view (Prototype) (b) Front view