OPTIMIZATION OF 5.8 GHz FRONT END RECEIVERS
FOR WiMAX APPLICATION
MUZAFFAR BIN MUSTAFFA
This report is submitted in partial of the requirement for the award of Bachelor of
Electronic Engineering (Telecommunication Electronics) With Honours
Faculty of Electronic and Computer Engineering
Universiti Teknikal Malaysia Melaka
May 2009
ii
UNIVERSTI TEKNIKAL MALAYSIA MELAKA FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN
PROJEK SARJANA MUDA II
Tajuk Projek : OPTIMIZATION OF 5.8 GHz FRONT END RECEIVERS
FOR WiMAX APPLICATION Sesi Pengajian : 2006/2009
Saya MUZAFFAR BIN MUSTAFFA mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat 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) (COP DAN TANDATANGAN PENYELIA)
Alamat Tetap: 12 JALAN SELASIH 15, TAMAN SELASIH 68100 BATU CAVES
SELANGOR
Tarikh: 30 APRIL 2008 Tarikh: 30 APRIL 2008
iii
“I hereby declare that this report is the result of my own work except for quotes as cited
in the reference”
Signature : ………………………………….
Author : MUZAFFAR BIN MUSTAFFA
Date : 30 APRIL 2009
iv
“I hereby declare that I have read this report and in my opinion this report is sufficient in
terms scope and quality for the award of Bachelor of Electronic Engineering (Computer
Engineering) With Honours”
Signature : ……………………………………………
Name : PN ZAITON BINTI ABDUL MUTALIP
Date : 30 APRIL 2009
v
Special dedication to my late father, Mustaffa Bin Nawawi and my mother, Mazanah
Binti Jaafar.
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ACKNOWLEDGEMENTS
I would like to extend my sincere gratitude to my supervisor, Pn Zaiton Binti
Abdul Mutalip, for her assistance and guidance toward the progress of this thesis project.
Through the year, she has been patiently monitoring my progress and guided me in the
right direction and offering encouragement. Obviously the progress I had now will be
uncertain without her assistance. My special appreciation and thank to my friend for their
invaluable assistances towards this thesis project. I also would like to thank to my family
without their support and understanding this would not have been possible.
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ABSTRACT
This report explores how to design the Low Noise Amplifier that was used in the
front end receiver for the WiMAX application. This report also explains the
fundamental knowledge in designing the Low Noise Amplifier. The fundamental
objective of this project is to design and optimize the 5.8 GHz front end receiver.
However, the main focus of this project is the designing and optimization of the Low
Noise Amplifier. All the basic parameter and fundamental theory are described in detail.
The result of the design will be revealed and discussed.
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ABSTRAK
Laporan ini mengkaji kaedah untuk mereka-bentuk penguat rendah hingar untuk
pengunaan aplikasi WiMAX. Laporan ini turut menerangkan pengetahuan asas di dalam
kaedah mereka-bentuk penguat rendah hingar. Objektif asas kajian ini adalah untuk
mereka – bentuk penguat rendah hingar dan mengoptima penerima bahagian depan radio
frekuensi. Walau bagaimanapun, laporan ini memfokus pada bahagian mereka-bentuk
penguat rendah hingar. Segala parameter dan teori asas diterangkan secara mendalam.
Hasil projek ini akan didedahkan serta dibincangkan di akhir laporan ini.
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CONTENTS
CHAPTER TITLE PAGES
PROJECT TITLE i
STATUS REPORT FORM ii
STUDENT DECLARATION iii
SUPERVISOR DECLARATION iv
DEDICATION v
ACKNOWLEDGEMENT
vi
ABSTRACT vii
CONTENT ix
LIST OF TABLE xii
LIST OF FIGURE xiii
LIST OF ABBREVIATIONS xv
I INTRODUCTION
1.1 Project Introduction 1
1.2 Objective 2
1.3 Problem Statement 3
1.4 Scope of Work 3
x
1.5 Methodology 4
1.6 Report Structure 4
II LITERATURE REVIEW
2.1 Inroduction to WiMAX 6
2.2 RF Front End Block Diagram 8
2.3 LNA Design 9
2.4 DC Biasing Technique 9
2.5 Stability 11
2.5.1 Consideration for stability in high frequency
amplifier design
11
2.5.2 Stability Decision 11
2.6 Gains 13
2.6.1Two-Port Power Gain
13
2.7 Noise in Amplifiers
17
2.8 Input and Output Matching.
19
2.9 Related Software
20
2.9.1 MathCAD Software
20
2.9.2 Ansoft Designer SV
22
2.9.2.1 Analysis
22
2.9.2.2 Features
23
2.9.3 Agilent Advance Design Systems 23
2.9.4 AWR Microwave Office
24
2.9.5 Software Decision
25
III RESEARCH METHODOLOGY
3.1 Understanding the project 26
3.2 Theoretical and statistical analysis 27
xi
3.2.1 Mathcad Calculation Steps
28
3.3 Simulation of designed amplifier circuit
30
3.3.1 ADS Simulation Steps 30
3.4 Result Discussion 38
IV RESULT ANALYSIS
4.1 Transistor Selection 40
4.2 Analytical Analysis 42
4.2.1 Stability 42
4.2.2 Gain 43
4.2.3 Noise figure 44
4.3 Simulation Analysis 45
4.3.1 Low Noise Amplifier Simulation 45
4.3.2 Front End Receiver Simulation 48
V DISCUSSION AND CONCLUSION
5.1 Discussion
50
5.2 Conclusion
51
5.3 Future Work
52
REFERENCES 53
BIBLIOGRAPHY 55
xii
LIST OF TABLES
TABLE TITLE PAGE
2.1 Comparison Between WiMAX and WLAN 7
2.5.2.1 Decision by formula
11
2.5.2.2 Decision by stability circle
12
xiii
LIST OF FIGURES
FIGURE TITLE PAGE
2.2.1 Front end receiver block diagram 8
2.4.1 Five basic DC bias networks. 10
2.5.1 Output stability circles for conditionally stable device. 12
2.5.2 Example of stability circles 13
2.6.1.1 A two-port network with general source and load
impedances
14
2.8.1 A lossless network matching networks arbitrary load
impedance to
a transmission line 20
2.8.1 Definition symbol 21
2.8.2 Mathematical expression 21
3.2.1.1 Creating new file 28
3.2.1.2 Variable declaration 29
3.2.1.3 Error notification 29
3.2.1.4 Example of complete calculation without error 30
3.3.1.1 Creating new project 31
3.3.1.2 Project view 31
3.3.1.3 Component Group List 32
3.3.1.4 Component Placement 32
3.3.1.5 Component connection using wire 33
3.3.1.6 Tool selection 34
3.3.1.7 Smith Chart Tool 34
xiv
3.3.1.8 Impedance Value 35
3.3.1.9 Example of complete circuit 35
3.3.1.10 Result window 36
3.3.1.11 Data selection in Result 37
3.3.1.12 Example of Result 37
3.1 Project Flow 39
4.1.1 S-parameter provided in the data sheet 41
4.1.2 S-parameter generated using ADS 2005A 41
4.2.1 Stability calculation 42
4.2.2.1 Power Gain calculation 43
4.2.2.2 Available Gain calculation 43
4.2.2.3 Transducer Gain calculation 44
4.2.3.1 Noise Figure calculation 44
4.3.1.1 Complete circuit of Matching Network for the Low
Noise Amplifier
46
4.3.1.2 Output Gain of the Low Noise Amplifier 46
4.3.1.3 Output Gain of the Low Noise Amplifier 47
4.3.1.4 Reflection Coefficients of the Low Noise Amplifier 47
4.3.2.1 Front End Receiver Architecture
48
4.3.2.1 Front End Receiver Output 49
xv
LIST OF ABBREVIATIONS
WiFi - Wireless Fidelity
WiMAX - Worldwide Interoperability Microwave Access
RF - Radio frequency
LNA - Low Noise Amplifier
DC - Direct current
QoS - Quality of Services
VSWR - Voltage Standing Wave Ratio
ADS - Advance Design System
1
CHAPTER 1
INTRODUCTION
Chapter one is focusing on the project background, project’s objectives, problem’s
statements, scope of work, methodology and organization of thesis.
1.1 Project Introduction
Wireless connectivity is very common on these days. The most popular wireless
connectivity for today is Wireless Fidelity (WiFi). WiFi is using the 802.11b and 802.11g
standard which is operated at 2.4GHz. However, this 2.4GHz channel is quite congested. These
channel are not only been used for Wifi but also for Bluetooth, WPAN-CSS (Wireless Personal
Area Network using Chirp Spread Spectrum technique) and ZigBee.
2
However, there are new standard that has been introduced by IEEE which is the 802.16d
and 802.16e. These standards are basically known as WiMax. WiMax are operating at channel of
3.5GHz and 5.8GHz. The 3.5GHz spectrum is a licensed spectrum and the 5.8GHz spectrum is
the unlicensed spectrum.
Front end receiver is the first part of equipment in receiving signal. Basically front end
receiver consists of antenna, Low Noise Amplifier (LNA), Radio Frequency (RF) amplifier,
Power Divider and Band Pass Filter. LNA is an integrated component of most RF systems. In
order to sustain a good signal reception, the total gain of the system should be in big number
while the noise figure should be as low as it could be.
In order to get the best signal, the parameter in the LNA and the RF amplifier can be
manipulate. Theoretically, by improving the gain of the system, the noise figure also will be
increased. The only solution is to find the optimum system in terms of great gain and minimum
noise.
1.2 Objective
The main purpose of this report are to document the learning process involved in the
design and optimize theoretically of LNA that been used in 5.8 GHz operating frequency for the
WiMAX application.
3
The objectives of this LNA design are to understand the concept of WiMAX
communication and RF amplifier system, to know the different between narrow band amplifier
and broadband amplifier, to design a Low Noise Amplifier that can operate in WiMAX
frequency that is 5.8 GHz and finally the design will be simulated by using simulation software
such as Advance System Designer.
1.3 Problem Statement
In general, the Low Noise Amplifier combines reasonable gain, good noise figure and
also stability over entire useful range of frequency. Designing LNA will present challenges in
obtaining high gain, low noise figure, good input and output matching, and the stability over
certain range of frequency. There are certain criteria needs to be look upon during designing
LNA. Those criteria are low supply voltage, low current consumption, high gain, high isolation
and input return loss. Low Noise Amplifier usually implies RF/wireless applications thus the
circuit needs to be small and cheap in order to be used widely. In order to achieve that, the
matching networks can be changed to lump elements for space reduction and cost saving.
1.4 Scope of Work
The scope for this project is to develop and optimize theoretically the LNA and RF
amplifier for the 5.8GHz front end receiver for WiMAX application. This project will only cover
the theoretical analysis which involves the calculation of all the parameters. This project also
will be simulated using simulation software in order to verify the theoretical results. The target of
gain to be achieved is 30dB.
4
1.5 Methodology
The work progress of this project is divided into four main parts:
Understanding the operation of front end receiver, Mathcad, and Advance System
Designer software.
In this part, all the literature review was done. The process included collection of
internet journal, online tutorial and also material collection from printed material.
Theoretical and statistical analysis of LNA using Mathcad.
All the formula was formed in the software which then will be calculated using the
software function itself.
Simulation of designed amplifier circuit using Advance System Designer.
Comparing the theoretical analysis and simulation result.
If problem occur, such as, the theoretical and simulation result doesn’t match, the process will be
repeated from simulation stage
1.6 Report Structure
This report was divided into five chapters. The first chapter is focusing on the
introductions of the project. The introduction consist of the project brief introduction, objective
of the project, the project statement, scope of work, project methodology and the report structure.
5
The second chapter is about the literature review. This chapter is focusing on the
documentation of the theory that related in designing the Low Noise Amplifier. The reviews of
previous case study are also included in this chapter.
The third chapter is mainly about the research methodology. All the progress and work
flow are described in this chapter.
The fourth chapter is about the project progress focusing on the result of the simulation.
All the data that were obtained will be documented in this chapter. The full project results are
shown.
The final chapter is focusing on the discussion and conclusion of this report. These
include the entire result and its justification. Some suggestion on improving this project also will
be discussed.
CHAPTER 2
LITERATURE REVIEW
This chapter reviews some references from previous project, journal, article,
books and data sheet. All these information was collected from the different sources
such as library, internet, product manual and etc. The useful data will be discussed on
the chapter.
2.1 Inroduction to WiMAX
WiMAX is actually the short form of Worldwide Interoperability Microwave
Access. This term is agreed between several companies to be used in general. The actual
name for this standard is IEEE 802.16. [1] This standard is a wireless digital
communication system that is intended for metropolitan area that provides interoperable
broadband wireless connectivity to every person in the metropolitan area. It provides up
7
to 50 kilometers of service area for fixed station, 5 to 15 kilometer for mobile station
allowing user to get broadband connectivity without the need of direct line of sight to the
base station. The WiMAX complaint system will provide a cost effective broadband
access to user at home, in the office, in the areas under-served by wire-line Digital
Subscriber Line (DSL) and cable services and even to users on the move equipped with
portable devides such as laptop and personal digital assistance (PDA).
Table 2.1 Comparison between WiMAX and WLAN
Parameter WiMAX WLAN
Frequency Band 2 to 11 GHz 2.4 GHz
Range 31 miles 100 meters
Data Transfer Rate 70 Mbps 11 Mbps~55 Mbps
Number of user Thousand Dozens
The WiMAX standard relies upon a grant-request access protocol that does not allow
data collision and therefore, uses the available bandwidth more efficiently. No collision
means any loss of bandwidth due to data retransmission. All communication is
coordinate by the base station. The main characteristic of the WiMAX standard include;
Long range of service area – the service area of WiMAX standard can be up to
30 miles.
Higher quality of services – the QoS of WiMAX is definitely higher compare to
other standard due to no collision protocol.
Wireless – WiMAX system is based on the wireless technology therefore the
mobility of new technology can be implemented.
8
2.2 RF Front End Block Diagram
Direct conversion, also known as homodyne or zero-IF conversion, is a natural
approach to convert an RF signal directly to baseband. A baseband signal has all the
frequencies from 0 Hz to the highest frequency component with significant power. After
the frequency it changed for transmission the higher frequency RF signal will have at
least double what the baseband signal had initially. Alternately, one can think of
choosing IF to be zero. The architecture of the proposed project;
Figure 2.2.1 Front end receiver block diagram. [2]
In this project, the part that is being concerned is RF component part or specifically the
low noise amplifier part. The low-noise amplifier (LNA) is a special type of electronic
amplifier or amplifier used in the systems to amplify very weak signals captured by an
antenna. The important things, the LNA deals with noise where LNA remove the noise
even though not totally remove all the signal but it still an important part that dealing
with noise. It just likes reducing the signal noise that came through antenna.
9
2.3 LNA Design
Microwave Transistor Amplifier is design using the scattered parameters (S
parameter). Microwave amplifiers combine active elements with passive transmission
line circuits to provide functions critical to microwave systems and instrument. The
history of microwave amplifiers begins with electrons device using resonant or slow-
wave structures to match wave velocity to electron beam velocity. [3]
The design techniques used for BJT and FET amplifiers employ the full range of
concepts that have been developed in the study of microwave transmission lines, two-
port network and Smith chart presentation. [4]
The development of S-parameter matrix concepts grew from the need to
characterize active devices and amplifiers in a form that recognized the need for
matched termination rather than short-or open circuit termination.
2.4 DC Biasing Technique
DC biasing is an important design consideration for proper operation of
amplifiers [5]. The ideal biasing arrangement should select the proper quiescent point
and hold the quiescent point constant over variation in the transistor parameter and
temperature. This is due to large temperature changed in an active bias network. The DC
and RF circuit should be isolated in order to make sure no RF signal will leak into the
DC biasing circuit and the DC biasing circuit does not disturb the RF performance. In