LIST OF FIGURES
NO. TITLE
PAGE
1.1 Flow Chart of Methodology
7 2.1
Magnetic Fields and Electric Field Produced by RF
Signals
11
2.2 Antenna as a Transitional Structure
11 2.3
Antenna Analysis of a Coordinate System 13
2.4 A Pyramidal Horn Antenna of Principal E- and H-Plane
Patterns 14
2.5 Polar Plot of Antenna Radiation Pattern
15 2.6
Cartesian Plot of Antenna Radiation Pattern 15
2.7 Radiation of Rectangular Waveguide
19 2.8
Monopole Feed into Waveguide 19
2.9 E-Plane Horn
21 2.10
H-Plane Horn 21
2.11 Rectangular Horn
22 2.12
1-18GHz Antenna Model with Transparent Flares 26
2.13 Model of Dual-Ridged Horn Antenna Feeding Section
27
3.1 Flow Chart How to Develop of Quad-Ridged Horn
Antenna for UWB Communications 29
3.2 Cross Section of Horn Antenna
32 3.3
Pyramidal Horn E-Plane View 32
3.4 Pyramidal Horn H-Plane View
33 3.5
Configuration of the Proposed Horn Antenna 35
3.6 Two Ports Quadruple-Ridged Waveguide
36
3.7 Vertical and Horizontal Ridges in Waveguide Transition
36 3.8
The Quad-Ridged Horn Antenna made from Ten Smaller Waveguide
38
3.9 Quad-Ridged Horn Antenna Design by using CST Software 38
3.10 Setting of Waveguide Port in CST Software 40
3.11 Flow Chart of the Fabrication Process 41
3.12 Measurement Setup for S-Parameter 42
3.13 Measurement Setup for Radiation Pattern in Anechoic
Chamber 42
3.14 Horn Antenna Setup used to Measure Gain of AUT 43
4.1 S
11
Parameter and Bandwidth of Quad-Ridged Horn Antenna
51
4.2 Measured S
11
Parameter after the Fabrication 52 4.3
Simulation of Directivity 52
4.4 Simulation of Radiation Pattern
53 4.5
Simulation of Gain 54
4.6 Measured of Gain after the Fabrication
54
LIST OF SYMBOLS
BW -
Bandwidth
c -
Speed of light
D -
Directivity εr
-
Dielectric constant
fr -
Resonant frequency
G -
Gain
L
eff
-
Effective length
RL -
Return loss
tan
δ -
Tangential loss
VSWR
- Return loss
Γ -
Reflection coefficient
A
eff
- Aperture of horn antenna
P
R
- Power radiated
P
T
- Power transmitted
G
T
- Gain of transmitter
G
R
- Gain of receiver
P
CL1
- Cable loss of cable 1
P
CL2
- Cable loss of cable 2
λ -
Waveguide length
d
- Distance
HPBW
- Half-Power Beam Width
e
o
- Total efficiency
e
r
- Reflections efficiency
e
c
- Conduction efficiency
e
d
- Dielectric efficiency
LIST OF APPENDICES
NO. TITLE
PAGE A
Specification Gain for Horn Antenna 72
CHAPTER I
INTRODUCTION
1.1 Introduction
In the era of advanced technology, Ultra Wide Band UWB communications system provides a very different approach to wireless technologies
compare to conventional narrow band systems. This brings huge research interests in it. Because of this, UWB has many potential applications to be researched. One of
the assuring applications areas using UWB is in medicine.
Some unique features of UWB are in medicine. Some unique features of UWB make it very suitable for medical areas. Ultra-wideband UWB radio is an
emerging technology with some unique attractive features, which are combined with researches in other fields such as wireless communications, radar, and medical
engineering fields. UWB can be applied to any band segmentations, such as single, dual and multi-bands.
Usually, the UWB system covers the frequency of 3.1-10.6GHz. Formally, before 2001, UWB’s application is limited mainly in military areas. However, since
2002, Federal Communications Commission FCC has gradually allowed the commercial usage of these bandwidths, which makes it possible that all common
people could use the benefit of UWB features[4]. The FCC regulates that the frequency for the UWB band is from 3.1GHz to 10.6GHz in America. It is known
the UWB pulse is generated in a very short time period sub-nanosecond. So, it has spectrum below the allowed noise level. This feature makes it possible to get
Gigabit per second Gbps speed by using 10GHz spectrum. So, UWB is suitable to be used for high-speed over short distances. UWB is often deemed as a possible
alternative of remote sensing and imaging.
Compared with X-ray imaging, UWB radar probes use non-ionizing electromagnetic waves, which proved to be harmless to human body. Moreover, the
UWB radar has very low average power level and is very power efficient[5]. This is suitable to be a potentially cost effective way of human body imaging, especially in
real time imaging.
By 1999, many works have begun for UWB medical applications in cardiology, obstetrics, breath pathways and arteries. Besides, UWB has many other
applications such as high-resolution penetrating radar, hidden object detection system, EMC experiments, free-space time domain FTD measurements systems
and feed for reflectors[3].
UWB technology has many benefits due to its ultra-wideband nature, which include the following:
i. High data rate
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