i DESIGN POWER AMPLIFIER FOR GPS APPLICATION SURIANI

i DESIGN POWER AMPLIFIER FOR GPS APPLICATION SURIANI
i
DESIGN POWER AMPLIFIER FOR GPS APPLICATION
SURIANI BINTI MD NAYAN
This Report is Submitted in Partial Fulfillment of Requirements for the Bachelor
Degree of Electronic Engineering (Telecommunication Electronics)
Faculty of Electronic and Computer Engineering
Universiti Teknikal Malaysia Melaka
April 2011
ii
UNIVERSTI TEKNIKAL MALAYSIA MELAKA
FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN
PROJEK SARJANA MUDA II
Tajuk Projek
:
Sesi
Pengajian
:
Saya
DESIGN POWER AMPLIFIER FOR GPS APPLICATION
BASE ON S-PARAMETER
1
0
/
1
1
SURIANI BINTI MD NAYAN
mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syaratsyarat kegunaan seperti berikut:
1.
Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.
2.
Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.
3.
Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara institusi
pengajian tinggi.
4.
Sila tandakan ( √ ) :
SULIT*
*(Mengandungi maklumat yang berdarjah keselamatan atau
kepentingan Malaysia seperti yang termaktub di dalam AKTA
RAHSIA RASMI 1972)
TERHAD**
**(Mengandungi maklumat terhad yang telah ditentukan oleh
organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD
Disahkan oleh:
__________________________
(TANDATANGAN PENULIS)
Tarikh: 21 APRIL 2011
___________________________________
(COP DAN TANDATANGAN PENYELIA)
Tarikh: 21 APRIL 2011
iii
“I hereby declare that this report is the result of my own work except for quotes as
cited in the references “
Signature
:……………………………………………
Author
: SURIANI BINTI MD NAYAN
Date
: 21 APRIL 2011
iv
“I hereby declare that I have read this report and in my opinion this report is
sufficient in terms of the scope and quality for the award of Bachelor of Electronic
Engineering ( Telecommunication Electronics) with Honours.”
:
Signature
:……………………………………………
Supervisor Name
:
Date
: 21 APRIL 2011
v
ACKNOWLEDGEMENT
I wish to express sincere, heartfelt appreciation to those involved in the completion of
this project.
First and foremost, I wish to express special thanks, appreciation and deep gratitude t my
project supervisor, Encik Azahari bin Salleh, who has been there to provide continuous guidance,
advice, encouragement, support and generous amount of time in helping me to complete this
project. His remarkable unique ways and professionalism of handling my weaknesses has turned
my simplistic mind to see think in more rational and critical view. It has been a great pleasure
and privilege tp learn from someone who is professional like him.
Sincere appreciation of course goes to my friends who give me unselfish support and
special thanks to my parents, Md Nayan bin Md Isa and my mother Zauyah binti Mat Isa because
always support me.
Above all, I would like to offer my deepest appreciation and thanks giving to Allah
S.W.T. There is ni way to measure what You’ve worth. You are The One who has made things
possible. You deserve all glory and honor.
vi
ABSTRACT
This thesis is analyzing the Power Amplifier for GPS Application. The power
amplifier is in the transmitting chain of the GPS system. They are the final amplification
stage before the signal is transmitted. Its must produced enough output power to
overcome channel losses between the transmitter and receiver signal gain. The ultimate
goal is to design a Power Amplifier which covers range of GPS L1 frequency at 1.575
GHz. The design will focus on designing of matching network base on three difference
types of matching network which is single stub element, quarter-wave element and
lumped element. Matching is important because to maximize power delivery and
minimize power loss and to improve signal to noise ratio as in sensitive components.
This power amplifier design is to achieve high power output, gain, noise figure, and
insertion loss through the GPS frequency range. The stability analysis of power
amplifier is one of the most critical and the most challenging aspects of power amplifier
design. This work shows an analysis technique, which accurately predicts the
oscillations in power amplifier. Using the technique, different matching techniques and
circuits are design and implementation. The transistor was choosing is NPN Bipolar
power transistor (AT-41533). The frequency for AT-41533 power transistor is up to 5
GHz. The power amplifier is design based on simulation using AWR Software and the
output gain is 15.921 dB using single stub element, 15.13 dB by using quarter wave
element and 14.953 dB by using lumped element. From the analysis, we know that
single stub element is the good impedance matching because it can fulfill the
requirement parameter of the GPS application.
vii
ABSTRAK
Tesis ini menganalisis Penguat Kuasa untuk Aplikasi Sistem Kedudukan Global
(GPS). Penguat kuasa dalam rantai penghantaran dari Sistem Kedudukan Global. Ia
adalah tahap amplifikasi terakhir sebelum isyarat ini dihantar kepada penerima. Kuasa
keluaran yang dihasilkan perlu cukup untuk mengatasi kerugian saluran antara pemancar
dan penerima isyarat keuntungan. Tujuan utamanya adalah untuk mereka bentuk sebuah
Penguat Kuasa yang merangkumi frekuensi L1 GPS di 1.575 GHz. Rekaan akan fokus
pada perancangan yang sesuai pangkalan rangkaian pada tiga jenis perbezaan rangkaian
pencocokan yang tunas elemen tunggal, unsur suku gelombang dan elemen lumped.
Pencocokan ini penting kerana untuk memaksimumkan penghantaran kuasa dan
meminimumkan kerugian daya dan untuk meningkatkan nisbah isyarat terhadap hingar
seperti dalam komponen-komponen sensitif. Rekaan power amplifier ini adalah untuk
mencapai keluaran yang tinggi, gain, noise figure, dan insertion loss melalui julat
frekuensi GPS. Analisis kestabilan power amplifier adalah salah satu yang paling
kritikal dan aspek yang paling mencabar dari mereka bentuk power amplifier. Karya ini
menunjukkan sebuah teknik analisis yang tepat memprediksi ayunan di power amplifier.
Dengan menggunakan teknik ini, teknik pencocokan yang berbeza dan litar adalah
rekaan dan pelaksanaan. Transistor yang dipilih adalah Bipolar NPN transistor kuasa
(AT-41533). Frekuensi untuk AT-41533 transistor kuasa hingga 5 GHz. Penguat kuasa
rekaan berdasarkan simulasi menggunakan perisian AWR ialah 15,921 dB gain keluaran
menggunakan elemen stub tunggal, 15.13 dB dengan menggunakan elemen gelombang
suku dan 14.953 dB dengan menggunakan elemen lumped. Dari analisis, kita tahu
bahawa elemen tunas tunggal adalah pencocokan impedansi baik kerana dapat
memenuhi keperluan parameter dari aplikasi GPS.
viii
CONTENTS
CHAPTER
I
II
TOPIC
PAGES
INTRODUCTION
1.1
Project Background
1
1.2
Objective
2
1.3
Problem Statement
2
1.4
Project Scope
3
1.5
Thesis Outline
3
GLOBAL POSITIONING SYSTEM
2.1
Global Positioning System (GPS)
5
2.2
GPS Orbits
6
2.3
GPS Signals
6
2.4
L1 Carrier Frequency
7
2.5
Demodulation and Decoding
8
2.6
Application of GPS
10
2.6.1 Roads and highway
10
2.6.2 Space
12
2.6.3 Rails
13
2.6.4 Aviation
14
2.6.5 Marine
15
2.6.6 Agriculture
15
ix
III
AMPLIFIER DESIGN
3.1
Power Amplifier
17
3.1.1 Efficiency
18
3.1.2 Power Gain/ Voltage Gain
18
3.1.3 Linearity
19
3.1.4 1-dB compression
19
3.1.5 Power Consumption
20
3.1.6 Noise Figure
20
Class of Amplifier
20
3.2.1 Class A operations
21
3.3
Single Stage Amplifier
22
3.4
Scattering Parameters
23
3.5
Two-port Scattering Parameters
24
3.6
Relationship with voltage and current
25
3.7
Meanings of s-parameters
25
3.8
Gain Definitions in Power Amplifier
26
3.9
Transducer Power Gain of Two-Port Circuit
27
3.10
Stability of Amplifier
29
3.10.1 Conditions for Stability
29
DC Biasing
31
3.2
3.11
IV
PROJECT METHODOLOGY
4.1
Project Expectation Work Flow
33
4.2
Stability
35
4.3
Matching
36
4 .3.1 Lumped Element
38
4.3.2 Single Stub Element
40
4.3.3 Quarter-wave Element
44
x
V
RESULT AND DISCUSSION
5.1
Selection of transistor
47
5.2
Calculation
49
5.3
Stability Consideration
54
5.4
IV Curve
55
5.5
DC Biasing Simulation Result
56
5.6
Matching Simulation Result
57
5.7
Type of input and output matching
57
5.7.1 Single Stub Matching Network
57
5.7.2 Quarter Wave Matching Network
58
5.7.3 Lumped Element Matching Network
58
S-Parameter Results
59
5.8.1 S21 Output Graft
59
5.8.2 Input Return Loss
60
5.8.3 Output Return Loss
62
5.8.4 Insertion Loss
63
5.8.5 Available Gain
64
5.8.6 Maximum Available Gain
65
5.8.7 Maximum Stable Gain
66
5.8.8 Power Gain
66
5.8.9 Transducer Gain
67
5.8.10 Current Gain
68
5.8.11 Noise Figure
71
Discussion
72
5.8
5.9
VI
CONCLUSION AND RECOMMENDATION
6.1
Conclusion
73
6.2
Future Work
74
xi
LIST OF FIGURES
FIGURE
TITLE
PAGES
Figure 1.1
Power Amplifier on GPS System
2
Figure 2.1
NAVSTAR GPS System Segments
6
Figure 2.2
GPS Signal Code and Carrier Frequency
7
Figure 2.3
GPS Satellite Transmission
8
Figure 2.4
Satellite Signals
9
Figure 2.5
Road and Highway
11
Figure 2.6
Space Application
12
Figure 2.7
Rail Application
13
Figure 2.8
Aviation Application
14
Figure 2.9
Marine Application
15
Figure 2.10
Agriculture Application
15
Figure 2.11
1-dB Compression Characteristics
18
Figure 2.13
General Transistor Amplifier Circuit
22
Figure 3.1
Project Expectation Work Flow
24
Figure 3.2
General Flow Chart of Designing GPS PA
26
Figure 3.3
Termination Matching Network
28
Figure 3.4
Waveguide Matching Network
28
Figure 3.5
Lumped Element Matching Network
30
Figure 3.6
Single Stub Matching Network
30
Figure 3.7
Quarter Wave Element
31
Figure 4.1
Scattering Parameter
34
Figure 4.2
Two-Port Scattering Parameters
35
Figure 4.3
S-parameters
36
xii
Figure 4.4
Transducer Power Gain using Z-parameters
37
Figure 4.5
Transducer Power Gain using S-parameters
38
Figure 4.6
Conditions for Stability
39
Figure 4.7
Unconditional Stability
40
Figure 4.8
Conditional Stability
40
Figure 5.1
Parameter define using AWR Software
43
Figure 5.2
S-Paramater define at frequency 1.575 MHz
43
Figure 5.3
Graft of Stability
44
Figure 5.4
Biasing Setup
45
Figure 5.5
IV Curve
45
Figure 5.6
DC Biasing
46
Figure 5.7
Single Stub Matching Network
47
Figure 5.8
Quarter Wave Matching Network
47
Figure 5.9
Lumped Element Matching Network
48
Figure 5.10
S21 Output Graft
49
Figure 5.11
S21 Output Optimization
49
Figure 5.12
Return Loss Input
50
Figure 5.13
Comparison Return Loss Input
51
Figure 5.14
Return Loss Output
51
Figure 5.15
Comparison Return Loss Output
52
Figure 5.16
Insertion Loss
53
Figure 5.17
Comparison Insertion Loss
53
Figure 5.18
Available Gain
54
Figure 5.19
Available Gain after Optimization
54
Figure 5.20
Maximum Available Gain
55
Figure 5.21
Maximum Available Gain after Optimization
55
Figure 5.22
Maximum Stable Gain
56
Figure 5.23
Operating Power Gain
56
Figure 5.24
Operating Power Gain after Optimization
57
Figure 5.25
Transducer Gain
57
Figure 5.26
Transducer Gain after Optimization
58
xiii
Figure 5.27
Current Gain at S21
58
Figure 5.28
Current Gain
59
Figure 5.29
Current Gain
59
Figure 5.30
Comparison Voltage Gain VTG
60
Figure 5.31
Voltage Gain VTG
60
Figure 5.32
Comparison Noise Figure
61
Figure 5.33
Comparison Noise Figure Min
61
xiv
LIST OF TABLE
TABLE
TITLE
PAGES
Table 1.1
Parameters Requirement
4
Table 5.1
Result based on type of Matching
72
xv
LIST OF APPENDIXS
APPENDIX
PAGES
APPENDIX A
77
APPENDIX B
80
APPENDIX C
81
APPENDIX D
82
APPENDIX E
83
CHAPTER I
INTRODUCTION
This chapter will discuss the overview process that involved for this project;
the aims and specific objectives of the project, problem statements, work scope,
methodology and result. The end of this chapter the thesis outline will be listed.
1.1
Project Background
This project implements the Power Amplifier (PA) for Global Positioning
System (GPS) system. It’s a software project but lastly must fabricate the result of
simulation. Power amplifier is building in satellite transponder on GPS transmission
system. Input signal is generally small and needs to be amplified sufficiently to
operate an output device. Power Amplifier is design to amplify that signal (RF
signal) and provides a large version of the signal that may direct to and antenna. It’s
also required to amplify the wanted signal without distortions and without other
impairments which would decrease the usefulness of the signal. Power Amplifier is
design operating in Class A linear mode over range of 1575.42 MHz. In this project,
the transistor was use is the power transistor. Figure 1.1 shows the Power Amplifier
on GPS system.
2
Figure 1.1: Power Amplifier on GPS system
1.2
Objective
Objective of this project is to design,, simulate and analysis the Power
Amplifier for GPS application. Design and analyze matching network base on sparameters for Power Amplifier at L1 Frequency (1575.42 MHz). The power
amplifier designed at L1 frequency (1575.42 MHz) for civilian.
1.3
Problem Statement
The amplifier is used to increase the signal that drives the signal to the
antenna. Without the amplifier, low-power radio-frequency cannot be converting into
a large signal of significant power. It’s also can’t optimized to have a high efficiency,
high output power compression, good return loss on the input and output, good gain
and optimum heat dissipation for driving a signal to the antenna. Signal also has a
loss, wanted signal with distortions and other impairments.
3
1.4
Project Scope
Scope for this project is analyzing the power amplifier for GPS system at L1
frequency. The frequency is 1575.42MHz. The software that will be use is AWR to
simulate the power amplifier. Analyze the power amplifier base on stability, gain,
input and output return loss at frequency 1.575 GHz using AWR software. Analyze
and comparison on type of matching network base on this element:-
(a)
Stub element
(b)
Quarter wave element
(c)
Lumped element
Table 1.1 shows the parameters that been used in this project:-
Table 1. 1 Parameters requirement
Parameter
Requirement
Operating frequency
1.575 GHz
Gain
>10dB
Bias Point
Transistor
1.5
VVE=2.7V
IC=10mA
AT-41533
Thesis Outline
Chapter 1 is about an introduction of project which includes an explanation of
project background, a brief introduction of Global Positioning System (GPS) and
Power Amplifier (PA), method used in Power Amplifier design, objectives of project,
and project scopes.
Chapter 2 of background study defines in detail about GPS and PA , and also
about method and type of matching used in the design work.
4
Chapter 3 contains a research methodology which includes the steps to design
power amplifier and a brief explanation of methodology flow chart.
Chapter 4 contains a details explanation of an amplifier design technique
which consist a single stage amplifier design, DC biasing design and input output
matching design.
Chapter 5 discusses about the selection of transistor and the result from this
project, S-parameter analysis, comparison matching network and all gain analysis.
Also include the calculation for design.
Chapter 6 reveals the conclusion of this project and future works suggestion
on this project.
5
CHAPTER II
GLOBAL POSITIONING SYSTEM
2.1
Global Positioning System (GPS)
The GPS system consists of three pieces. There are the satellites that transmit
the position information, there are the ground stations that are used to control the
satellites and update the information, and finally there is the receiver that we
purchased. It is the receiver that collects data from the satellites and computes its
location anywhere in the world based on information it gets from the satellites GPS
is part of a satellite-based navigation system developed by the U.S. Department of
Defense under its NAVSTAR satellite program. Figure 2.1 shows the NAVSTAR
GPS System Segments.
Figure 2. 1 NAVSTAR GPS System Segments
6
2.2
GPS Orbits
The fully operational GPS includes 24 or more active satellites approximately
uniformly dispersed around six circular orbits with four or more satellite each. The
orbits are inclined at an angle of 55o relative to the equator and are separated from
each other by multiples of 60o right ascension. The orbits are no geostationary and
approximately circular, with radii of 26,560km and orbital periods of one half
sidereal days. Theoretically, there are more GPS satellite will always be visible from
most points on the earth’s surface and four or more GPS satellite can be used to
determine an observer’s position anywhere on the earth’s surface 24 hour per day.
2.3
GPS signals
Each GPS satellite carries a cesium and/or rubidium atomic clock to provide
timing information for the signals transmitted by the satellites. Internal clock
correction is provided for each satellite clock. Each GPS satellite transmits two
spread spectrum, L-band carrier signal. L1 signal with carrier frequency and an L2
signal with carrier frequency. These two frequencies are integral multiples and of a
base frequency . The L1 signal from each satellite uses binary phase-shift keying
(BPSK), modulated by two pseudorandom noise (PRN) codes in phase quadrature,
designated as the C/A-code and P-code. The L2 signal from each satellite is BPSK
modulated by only the P-code. Figure 2.2 shows the GPS signals code and carrier
frequencies.
7
Figure 2. 2: GPS signal code and carrier frequencies
2.4
L1 carrier frequency
L1 is a civilian-use signal, to be broadcast on the same L1 frequency
(1575.42 MHz) that currently contains the C/A signal used by all current GPS users.
Figure 2.5 shows the demodulating and decoding signals in GPS system
Implementation will provide C/A code to ensure backward compatibility assured of
1.5 dB increases in minimum C/A code power to mitigate any noise floor increase.
Non-data signal component contains a pilot carrier to improve tracking enables
greater civil interoperability with Galileo L1. Figure 2.4 shows the signal that
transmits from satellite.
8
2.5
Demodulation and decoding
Figure 2.3 shows demodulating and decoding signal in GPS System.
Figure 2. 3: GPS satellite transmissions
Figure 2.4 shows the transmission signal from satellite
Figure 2. 4: Satellite signals
9
GPS satellites use the microwave L-band to broadcast three separate radionavigation signals on two separate RF channels usually called L1 (around 1.6 GHz)
and L2 (around 1.2 GHz). These frequencies were chosen as a compromise between
the required satellite transmitter power and ionospheric errors. The influence of the
ionosphere decreases with the square of the carrier frequency and is very small above
1 GHz. However, in a precision navigation system it still induces a position error of
about 50m at the L1 frequency during daylight and medium solar activity. On the
other hand, GPS were designed to work with omnidirectional, hemisphericalcoverage receiving antennas. The capture area of an antenna with a defined radiation
pattern decreases with the square of the operating frequency, so the power of the onboard transmitter has to be increased by the same amount.
GPS broadcast two different signals: a Coarse/Acquisition (C/A) signal and
Precision (P) signal. The C/A-signal is only transmitted on the higher frequency (L1)
while the P-signal is transmitted on two widely-separated RF channels (L1 and L2).
Since the frequency dependence of ionospheric errors is known, the absolute error on
each carrier frequency can be computed from the measured difference between the
two P-transmissions on L1 and L2 carries.
The L1 C/A- and P-carriers are in quadrature to enable a single power
amplifier to be used for both signals. The L1 and L2 transmitter outputs are
combined in a passive network and feed an array of helix antennas. These produce a
shaped beam covering the whole visible hemisphere from the GPS orbit with the
same signal strength.
All three GPS transmissions are continuous, straightforward BPSK modulated
carriers. Pulse modulation is not used. The timing information is transmitted in the
modulation: the user's receiver measures the time of arrival of a defined bit pattern,
which is a known code. If desired, the modulation code phase can be related to the
carrier phase in the receiver to produce even more accurate measurements, since both
the carrier frequency and the code rate are derived coherently from the same
reference frequency on-board the satellite.
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