MICROSTRIP ANTENNA FOR RADIO
SUZIWATI BT. FADZLI
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Universiti Malaysia Sarawak 2000 Boring Penyera6an Tesis Universiti A'hrlaysia Sarawak
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BORANG PENYERAHAN TESLS
Judul: Microstrip Antenna For Radio
SESI PENGAJIAN: 1997/2000
Saya SUZIWATIBT. FADZLI a (HURUF BESAR)
romgaku n,:.mbenarkan tesis ini disimpan di Pusat Khidmat Maklumat, Universiti Malaysia Sarawak dengan syarat-syaratkegunaan sepcrti baikut:
t. Hakmilik kertas projek adalah di bawah nama penulis melainkan penulisan sebagaiprojek bersemadan dibiayai oleb UNIMAS, hakmiliknya ad" kepunyaanUNIMAS. 2. Naskah salman di dalam bentuk kertas atau mikro hanya botch dibuat dengan kebenaran bertulis daripada penulis. 3. PusatKhidmat Maklumat Akademik, UNIMAS dibcnarkan membuat satinsn untuk pengajian mereka. 4. Kertas projek hanya botch diterbitkan dengan kebmaran penulis. Bayaran royalti adalah meng" kadar yang dipasetujui kelak 5. * Saya measberrarkazoltidakmembenadcan Perpustakaan membuat salinan kertas projek ini sebagai bahan pertukarandi antara institusi pengajian tinggi. 6. "" Sila tandakanW) SULIT (Mengandungimaklumat yang berdarjah keselamatangau kepentingan Malaysiaseperti yang termaktubdi dalam AKTA RAHSIA RASMI 1972).
TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badandi mans peayeGdikaondijalankan).
TIDAK TERNAD týl
Disahkan oleh
(TANDATANGAN PENULIS) (TANDATANGAN PENYELIA)
Alamat Tetap: No. 3 Jalan Haii Hashim Mr. Al Khalid Othman Jaafar Petra Jaya. 93050 Kuching Nama Penyelia Sarawak Tarikh: $ýfI 1000 Tarikh: t-/w /Q. ooo
CATATAN " Potang yang tidak berkeoaan. a" Jika Kertas Projck ini SULIT Mau TERHAD, sila lampirksa suret dwipada pihak berkuasal organisasi berkmaamdemgan menyatakan sekali tempab kertas projek. Inhperhu dikelaskam scbagaiSULIT atau TERHAD. This project report attahed hereto, entitled "Microstrip Antenna For
Radio". Prepared and submitted by Suziwati Bt. Fadzli as a parial
fulfillment of teh requirement for the degree of Barchelor of Engineering
with honours (Electronic and Telecommunication) is hereby read and
approved by:
---ýA 'ý $-/'} /2cc, rý o
Mr. Al Khalid Othman Date
Supervisor P. KHIDMAT MAKLUMAT UNIMAS l0000081711
MICROSTRIP ANTENNA FOR RADIO
SUZIWATI BT. FADZLI
Tesis Dikemukakan Hepada Fakulti Hejurateraan, Universiti Malaysia Sarawak Sebagai Memenuhi Sebahagian Daripada Syarat Penganugerahan Sarjana Muda Hejuruteraan Dengan Hepujian (Kejuruteraan Elektronik dan telekomunikasi) Mae 2000 ACKNOWLEDGEMENT
Bismillahirralumumirrahim Firstly, I would like to express my
gratitude to Mr. Al Khalid Othman for his advice and guidance and for
supervising this project. Mr. Thelaha Masri, who helpfully suggested many
improvements and ideas, deserves a special note of thanks for making many
useful suggestions for revision.
My thanks are also due to my family for their support and
encouragement.
Last, but not least, I owe especially important debts of gratitude to
directly all that had helped me and indirectly during the preparation of
this project.
indeed fortunate I am to have all of them with me over this year, and
I wish to thank them sincerely for their many-many efforts on my behalf.
il ABSTRACT
The "Microstrip Antenna For Radio" aims to live up to its title, as a useful
companion and reference for all who wish to extend their familiarity with
microstrip antenna. I have naturally concentrated on planar antenna,
which is one type of microstrip antenna, to replace the old dipole radio
antenna. The brief introduction to microstrip antenna is discussed in
chapter one while literature review is discussed in chapter two. The
problem why the planar antenna and FM frequency are chosen here are
also discussed in this thesis. The experiment set up and results and
discussion are discussed in chapter three and chapter four. The last
chapter discusses about the conclusion and further work. In doing my
thesis, the most problem I faced was the difficulty to find the suitable references as this project is new. As a result, this thesis report may contain some mistakes and confusion, I am very apologize for that.
iii ABSTRAK
Thesis bertajuk Microstrip Antenna For Radio bermatlamat untuk
dijadikan sebagai teman dan rujukan kepada mereka yang berhasrat untuk
memperluaskan atau melanjutkan pengetahuan mereka ke atas microstrip
antenna. Tesis ini lebih menekankan planar antenna, di mana ia
merupakan salah satu jenis microastrip antenna, untuk menggantikan
dipole radio antenna yang lama. Pengenalan kepada niicrostrip antenna
secara ringkasnya dibincangkan dalam bab satu sementara ulasan kajian
dibincangkan dalam bab dua. Persoalan mengapa planar antenna dan FM
frequency dipilih di sini juga turut dibincangkan dalam tesis ini.
Eksperimen serta keputusan dan perbincangan dibincangkan dalam bab
tiga dan bab empat. Bab akhir membincangkan kesimpulan dan tugas
selanjutnya. Dalam menajalankan tesis ini, masalah yang utama adalah kesulitan dalam mencari rujukan yang sesuai dan tepat memandangkan
projek ini masih baru lagi. Hasilnya, mungkin terdapat kesalahan dan kekeliruan dalam laporan tesis ini, oleh itu, harap maklum.
IV TABLE OF CONTENTS
ACKNOWLEDGEMENT ii ABSTRAK iii
ABSRACT iv
LIST OF TABLES viii
LIST OF FIGURES
CHAPTER 1
INTRODUCTION
1.1 BASIC ANTENNA THEORY 1
1.2 HISTORY OF MICROSTRIP ANTENNA 3
1.3 WHAT IS MICROSTRIP ANTENNA 4
1.4 PROJECT OBJECTIVES 8
1.5 PROJECT OVERVIEW 9
1.6 WHY CHOOSE FREQUENCY MODULATION (FM)
FREQUENCY 12
1.6.1 What Is FM? 12
1.6.2 Advantages Using FM 13
1.7 DIPOLE ANTENNA 14
Dipole 1.7.1 Antenna Impedance 16
1.72 Electrical versus Physical Length 17 CHAPTER 2
LITERATURE REVIEW
2.1 PLANAR STRIP TRANSMISSION LINE 18
2.1.1 Characteristic Impedance 19
2.2 IMPEDANCE MATCHING 19
2.3 DIELECTRIC LOSSES 21
2.4 EFFECTIVE LOSS TANGENT 21
2.5 DIELECTRIC CONSTANT 22
2.5.1 Effective Dielectric Constant 23
2.6 AVAILABLE MICROWAVE SUBSTRATE 23
2.7 FREQUENCY 24
2.8 BANDWIDTH 24
CHAPTER 3
THE IMPLEMENTED PLANAR ANTENNAS
3.1 SUBSTRATE 26
3.2 ETCHING PROCESS 27
3.3 IMPLEMENTING THE PATTERN OF PLANAR ANTENNAS 28
3.4 EXPERIMENT SET UP 30
3.4.1 Experiment 1 30
14.2 Experiment 2 31
vi 3.4.2.1 Experiment 2A 32
3.4.2.2 Experiment 2B 33
3.4.2.3 Experiment 2C 34
3.4.2.4 Experiment 2D 34
CHAPTER 4
RESULTS AND DISCUSSION
4.1 RESULTS 36
4.1.1 Results For Experiment 1 36
4.1.2 Results For Experiment 2A 36
4 1.3 Results For Experiment 2B . 57
4.1.4 Results For Experiment 2C 63
4.1.5 Results For Experiment 2D 67
4.2 DISCUSSION 69
CHAPTER 5
CONCLUSION AND FURTHER WORK
5.1 CONCLUSION 74
5.2 FURTHER WORK 75
REFERENCES 77
VIi LIST OF TABLES
TABLE
1.5 The ABA 20 and ABE 01 antenna for radio 9
4.1.2(a) Result for reference antenna at distance 35 cm 37
4.1.2(b) Result for antenna 1 at distance 35 cm 38
4.1.2(c) Result for antenna 2 at distance 35 cm 40
4.1.2(d) The combining results for reference antenna,
antenna 1 and antenna 2 at distance 35 cm 41
4.1.2(e) Result for reference antenna at distance 105 cm 43
4.1.2(f) Result for reference antenna at distance 175 cm 45
4.1.2(g) The combining results for reference antenna
at different distances 46
4.1.2(h) Result for antenna 1 at distance 105 cm 48
4.1.2(k) Result for antenna 1 at distance 175 cm 49
4.1.2(m) The combining results for antenna I at
different distances 51
4.1.2(n) Result for antenna 4 at distance 35 cm 52
4.1.2(p) Result for antenna 6 at distance 35 cm 54
4.1.2(r) The combining results for antenna 4 and
antenna 6 at distance 35 cm 55
viii 4.1.3(a) Result for antenna 3 (X > S) at distance 35 cm 57
4.1.3(b) Result for antenna 4 (X = S) at distance 35 cm 59
4.1.3(c) Result for antenna 5 (X < S) at distance 35 cm 60
4.1.3(d) The combining results for antenna 3,4, and 5
at distance 35 cm 62
4.1.4(a) Results for antenna 6 at distance 35 cm 63
4.1.4(b) Results for antenna 7 at distance 35 cm 65
4.1.4(c) The combining results for antenna 6 and
antenna 7 at distance 35 cm 66
4.1.5 Result for antenna 8 at distance 35 cm 68
ix LIST OF FIGURES
FIGURE
1.3(a) The Microstrip Antenna 4
1.3(b) Side-fed Antenna 5
1.3(c) Planar Antenna 5
1.3(d) Feed Point at one end 5
1.3(e) Single-Ended Microstrip Loop 6
1.3(f) Balanced Microstrip Loop 6
1.3(g) (a) Square Patch, Ground Plate Present and (b)
Coordinate for a Planar Square Patch antenna 7
1.3(h) (c) Circular Patch, Ground Plate Present and (d)
Coordinate for a Planar Circular Patch antenna 7
1.5 The MathCad Simulation 11.
1.7 Elementary Dipole 15
1.7.1 Impedance along a half wave antenna 17
2.1 Transmission line of planar strips 19
3.3(a) The Implemented Planar Antenna 1 29
3.3(b) The Implemented Planar Antenna 2 29
3.3(c) The Implemented Planar Antenna 3 29
x 3.4.1 The Equipment Used For Experiment 1 30
3.4.2 The Equipment Used For Experiment 2 31
3.4.2.1(a) Antenna 1 32
3.4.2.1(b) Antenna 2 32
3.4.2.1(c) Antenna 4 32
3.4.2.1(d) Antenna 6 32
3.4.2.2(a) Antenna 3: X>S 33
3.4.2.2(b) Antenna 4: X=S 33
3.4.2.2(c) Antenna 3: X
3.4.2.3(a) Antenna 6: Antenna with 5cm height 34
3.4.2.3(b) Antenna 7: Antenna with 8.5cm height 34
3.4.2.4 The Implemented Planar Antenna 3 35
4.1.2(a) Result for reference antenna at distance 35 cm 37
4.1.2(b) Result for antenna 1 at distance 35 cm 39
4.1.2(c) Result for antenna 2 at distance 35 cm 40
4.1.2(d) The combining result for reference antenna,
antenna 1, and antenna 2 at distance 35 cm 42
4.1.2(e) Result for reference antenna at distance 105 cm 44
4.1.2(f) Result for reference antenna at distance 175 cm 45
4.1.2(g) The combining results for reference antenna
at different distances 47
4.1.2(h) Result for antenna 1 at distance 105 em 48
xI CHAPTER 1
INTRODUCTION
1.1 BASIC ANTENNA THEORY
The IEEE Standard Definitions of terms for Antennas (IEEE Std 145 1983) defines the antenna or aerial as; "A means of radiating or receiving radio waves. "
In other words, the antenna is the transitional structure between
free-space and a guiding device. The guiding device or transmission line
may take the form of a coaxial line or a hollow pipe (waveguide), and it is
used to transport electromagnetic energy from the transmitting source to
the antenna, or from the antenna to the receiver.
Antennas serve either or both of the two functions: the generation and the collection of electromagnetic energy. In a transmitting system, a radio frequency (RF) signal is developed, amplified, modulated, and applied
The RF flowing to the antenna. currents through the antenna produce electromagnetic waves that radiate into the atmosphere. In a receiving system, electromagnetic waves "cutting" through the antenna induce alternating currents for use by the receiver.
To have adequate signal strength at the receiver, either the power transmitted or the efficiency of the transmitting and the receiving
I antennas must be high because of the high losses in wave travel between
the transmitter and receiver.
Any receiving antenna transfers energy from the atmosphere to its
terminals with the same efficiency with which it transfers energy from the
transmitter into the atmosphere. This property of interchangeability for
transmitting and receiving operations is known as antenna reciprocity.
Antenna reciprocity occurs because antenna characteristics are essentially
the same regardless of whether an antenna is sending or receiving
electromagnetic energy.
Because of reciprocity, antennas are generally treated from the
viewpoint of the transmitting antenna, with the understanding that the
same principles apply equally well when the antenna is used for receiving
electromagnetic energy.
Antennas produce or collect electromagnetic energy and should do so in an efficient manner. Consequently, antennas are composed of conductors arranged so as to permit efficient operation. Efficient operation also requires that the receiving antenna be of the same polarisation as the
Polarisation is transmitting antenna. the direction of the electric field and is, therefore, the same as the antenna's physical configuration. Thus, a vertical antenna will transmit a vertically polarised wave. The received
is if signal theoretically zero a vertical electric field cuts through a horizontal receiving antenna.
The received signal strength of an antenna is usually described in terms the field If of electric strength. a received signal induces a 10 µV
ý in signal an antenna 2 meter long, the field strength is 10 µV /2m, or 5 E.tV /
m 171.
1.2 HISTORY OF MICROSTRIP ANTENNA
Microstrip antenna concept dates back about 26 years to work in the
U. S. A. by Deschamps and in France by Gutton and Baissinot. Shortly
thereafter, Lewin investigated radiation from stripline discontinuities.
Kaloi, who studied basic rectangular and square configurations, undertook
additional studies in the late 1960's. However, other than the original
Deschamps report, work was not reported in the literature until the early
1970's, when a conducting strip radiator separated from a ground plane by
a dielectric substrate was described by Byron.
Garvin et al, Howell, Weinschel, and Janes and Wilson reported additional work on basic microstrip patch elements in 1975. The early work by Munson on the development of microstrips antennas for use as low profile flush-mounted antennas on rockets and missiles showed that this
for in was a practical concept use many antenna system problems, and thereby gave birth to a new antenna industry.
first The mathematical analysis of a wide variety of microstrip patch
in 1977 by Lo shapes was published et al. By 1978, the microstrip patch
becoming antenna was much more widely known and used in a variety of communication systems. In 1979, the first international meeting devoted to microstrip antenna materials, practical designs, array configurations, and theoretical models was held at New Mexico State University (NMSU), Las Cruces, under cosponsorship of the U. S. Army Research Office and NMSU's
Physical Science Laboratory 121.
1.3 WHAT IS MICROSTRIP ANTENNA
The word antenna is best referred to interface between the transmission line and free space. When a microwave radiating or receiving element is formed on top of an M IIC dielectric substrate with a complete ground plate, it is a microstrip antenna or a patch antenna depending on the shape of the pattern of the active element on the substrate. If a large part of the ground plate corresponding to the active element on the substrate is absent or the ground plate is completely missing, then it is a planar antenna.
STRIP
NEW
GROUND PLANE MATERIAL, er
Figure 1.3(a): The microstrip antenna
4 ºL h%ý Input
P. Figure 1.3(b): Side-fed antenna ?,12ý
4 ý;? º
Figure 1.3(c): Planar antenna I
Input
X/2
Figure 1.3(d): Feed point at one end
Input
Figure 1.3: (b), (c), and (d) above are all microstrip antenna. Figure
1.3(b) shows a side-fed microstrip half-wave dipole antenna. If feed point is moved, the impedance varies as well. The feed is chosen (the point Z) to be located such that the antenna impedance and the microstrip impedance are close to each other.
If the ground plate underneath the radiator shown in figure 1.3(b) is removed, the antenna becomes a planar antenna (figure 1.3(c)). The feed is different in this antenna. The microstrip planar antenna can be fed through a balanced parallel stripline or a conventional single microstrip line. When the conventional microstrip is attached to the feed point of one
element, the feed point of the other element must be grounded to the
ground plate. The radiation patterns from either of these antennas is the
same as that from the familiar half-wave dipole antenna. When fed from
one end (figure 1.3(d)), the antenna impedance is usually higher that the
characteristic impedance of the microstrip. Hence an impedance matching
transformer is needed (b).
Typical microstrip loop antennas are shown in figure 1.3: (e) and (f).
A single-ended microstrip loop is shown in figure 1.3(e), while a balanced
microstrip loop is shown in figure 1.3(f).
Ii ýý
06
Figure 1.3(e): Single-Ended Figure 1.3(f): Balanced
Microstrip Loop Microstrip Loop
A conducting square or circular patch formed on a dielectric substrate, as shown in figure 1.3: (g) and (h), can be used as an antenna. If
6 the ground plate is present, the radiation pattern is in both the Z and Y
directions. When the ground plate is not present, the antennas are planar
antennas. More specifically, planar antennas are considered end-fed X/2
dipole antennas. Here, there is very little radiation in the Z direction.
ý4- ,rC X'/1
(a) 1 Figure 1.3(gl): (a) Square Patch, Ground Plate Present and (b) Coordinate
For A Planar Square Patch Antenna
(d) (c)
Figure 1.3(h): (c) Circular Patch, Ground Plate Present and (d) Coordinate
For A Planar Circular Patch Antenna 151.
The term stripline and microstrip are often encountered in the literature, in connection with both transmission lines and antennas. A stripline or triplate device is a sandwich of three parallel conducting layers
7 separated by two thin dielectric substrates, the center conductor of which
is analogous to the center conductor of a coaxial transmission line. If the
center conductor couples to a resonant slot cut orthogonal in the upper
conductor, the device is said to be a stripline radiator (21.
There is still research and experiment to be carried out in the field of
antenna design and behavior, although nearly a century has passed since
Marconi's first demonstrations of radio communication (Marconi antenna
is a quarter-wave monopoly antenna that uses the image (reflective) effects
of a ground plane 11,51. And now, microstrip antenna technology has been
the most rapidly developing topic in the antenna field in the last fifteen
years, receiving the creative attentions of academic, industrial, and
government engineers and researches throughout the world (2).
1.4 PROJECT OBJECTIVES
The purposes of this project are:
i. to study the basic characteristics of dipole antenna.
ii. then to study most on planar antenna. iii. to have a literature review on planar antenna for radio.
iv. to implement the planar antennas.
v. to build and test the planar antennas to replace the old dipole radio
antenna
S 1.5 PROJECT OVERVIEW
There are many types of radio antennas now. Some of them, which are very common antennas, are dipole, monopole, and arrays.
TYPE ABA 20 ABE 01
CHANNEL FM FM
RECEIVING RANGE (M]Rz) 87 - 108 87 - 108 -i LENGTH (mm) 1485 1070
WEIGHT (kg) 0.85 -1 1-2.1 Table 1.5: The ABA 20 and ABE 01 antenna for radio
The table above has shown some of the type of antennas for radio.
Most of them are quite heavy compared to planar antenna.
The first consideration that should be taken into account is the frequency operation. It is important to know the frequency of operation since the value of wavelength, a,, need to be calculated from basic formulae: c=fxX, where c is the speed of light, 3x 10' m/s 131.
For FM channel, the receiving range is 87 to 108 MHz. So, when the frequency is 110 MHz, wavelength, X, is equal to:
} =3x10"/110x108
= 2.73 m.
9 There is a reason why planar antenna has been chosen here. Below is a MATHCAD simulation program for microstrip antenna by Thelaha Masri in determining the length and width of a rectangular microstrip antenna operating in range of frequency from 80 MHz to 200 MHz. It can be shown that the rectangular microstrip antenna is bigger than planar antenna. For frequency 80 MHz, the rectangular microstrip antenna will have
1.186mx 1.1417mwide.
10