Patch Antenna

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  • Topic: Antenna, Patch antenna, Impedance matching
  • Pages : 24 (3514 words )
  • Download(s) : 75
  • Published : March 19, 2013
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Microstrip Patch Antenna
Steve Jensen
sj443
NAU ID: 2931095
Fall 2010 • Northern Arizona University • December 14, 2010

Steve Jensen • email: steve@stevejensen.dk • Northern Arizona University

Introduction

Different types of microstrip patch antenna’s

Background
Although I grew up without knowing in which educational direction I might go, I have always been interested in gadgets and especially mobile phones. As I later became a student in Electrical Engineering I became more and more interested in wireless technology as I saw it had a big potential for the future. Growing up with fictional movies and dreams about what the future might bring, has also inspired me to think in terms of wireless technology. It has always been my plan to do something with wireless technology every since I became a student. Working for Nokia inspired me to connect the two dots together and I became interested in making a patch antenna.

I have previously worked on a pineapple antenna, which I constructed by assembling two cans after emptying the pineapple out of them. The same principle is widely known as the “Pringles Antenna” around the internet, after using a Pringles can.

Motivation
My motivation leaning about patch antennas is targeted through a future job, when I have gained more knowledge and experience besides this project.

2

Table of Contents

Objectives !

5

1. WI-FI!

6

1.1 Channels

6

2. Microstrip Antenna Theory!

7

2.1 Introduction to antennas

7

2.1.1 Antenna radiation

2.2 Basics of a transmission line
2.2.1 Transmission Line

7

9
9

2.2.2 Matching and reflection

10

2.2.3 VSWR

12

2.2.4 Return loss

12

2.2.5 S-parameters

12

2.4 Field regions

16

2.4.1 Near field

17

2.4.2 Far field

17

2.5 Bandwidth

18

1

2.6 Radiation pattern

20

2.6.1 Beamwidth

20

2.6 Microstrip antenna

21

2.6.1 Advantages and disadvantages

22

2.6.2 Q factor (Quality factor)

22

2.7 Antenna feed

23

2.7.1 Microstrip feed line

23

2.7.2 Coaxial feed

24

2.8 Transmission line model (Microstrip feed line)

25

2.8.1 Width

28

2.8.2 Length

28

2.8.3 Ground planes

28

3. PCB substrate!

29

3.1 Introduction

29

3.2 Substrate properties

30

3.2.1 Dielectric constant

30

3.2.2 Loss tangent

31

3.2.3 Thickness

32

3.2.3.1 Short Summary

32

3.2.5 Dielectric strength

33

3.3 Some Common substrates

33

3.4 Substrate materials

34

3.4.1 Ceramic substrate

34

3.4.2 Synthetic substrate

34

3.4.3 Composite material substrate

34

2

3.4.4 Low-cost low-loss substrate

34

3.4.5 FR-4

35

3.4.6 Rogers

36

3.7 My selection

37

3.8 Substrate losses & issues

38

3.8.1 Why dielectric loss occur

38

3.8.2 Impedance loss

38

3.8.3 Moisture absorption

38

3.8.4 Temperature expansion

38

4. Design!
4.1 Rogers 3003 design

39
39

4.1.1 Width

39

4.1.2 Effective dielectric constant

40

4.1.3 Effective length

40

4.1.4 Delta length

40

4.1.5 Actual length

40

4.1.6 Ground plane

40

4.2 FR-4 design

41

4.2.1 Width

41

4.2.2 Effective dielectric constant

41

4.2.3 Effective length

41

4.2.4 Delta length

41

4.2.5 Actual length

42

4.2.6 Ground plane

42

5. Simulations!

43

3

5.1 Application software

43

5.2 Rogers 3003 simulation

44

5.2.1 1. Design

44

5.2.2 2. Design

47

5.3 FR-4 simulation

51

5.3.1 1. Design

51

5.3.2 2. Design

54

5.3.3 3. Design

57

6. Conclusion !

61

Bibliography

63

Books

63

Internet sources

63
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