Designing of fractal antenna,RF Designing

1. FRACTALANTENNAS –A NOVEL
MINIATURIZATION TECHNIQUE
FOR WIRELESS COMMUNICATIONS
Prepared By : Patel Jay C
ME(EC)-140870705004

2. OBJECTIVE
 To provide a study of different fractal antenna with an overview of recent
developments.

3. FRACTAL ANTENNA – AN INTRODUCTION
 Fractal antenna theory – a new area
 “fractal ” means broken or irregular fragments
 “Family of complex shapes that possess an inherent self similarity or self
affinity in their geometrical structure”
 Came from unique occurances in nature

4. FRACTAL ANTENNA

5. FRACTAL ANTENNA
 Suggests some attractive solutions for using single small antenna needed
for different frequency bands (multiband operation)
 Size, area and mass reduction (miniaturization)
 The effective length of the antenna can be increased keeping the total area
same

6. GEOMETRY OF FRACTALS
 The shape can be formed by iterative mathematical process called IFS
 Based on series of affine transformations
w(x,y) = (ax+by+e, cx+dy+f)
○ a,b,c,d control rotation and scaling
○ e , f control linear translation
 Repeatedly applying W to the previous geometryfractal geometry
A1=W(A0); A2 = W (A1);……..

7. GEOMETRY OF FRACTALS
 IFS generated a sequence that converges to a final image
 More no. of iterations increase in effective length  decrease in resonant
frequency
 Fractal geometry used in most of the works:
 Koch fractal
 Sirepinski fractal
 Koch island fractal

8. A three iteration Sirepinski fractal
A FOUR ITERATION KOCH FRACTAL

9. A THREE ITERATION KOCH ISLAND

10. HOW MINIATURIZATION ?
 Achieving lower fr with reduced length is miniaturization.
 Fractal geometry comprise larger antenna length in a smaller
volume.

11. HOW MULTIBAND OPERATION?
 A single antenna operating in two
or more freuquency bands
multiband operation
 Antenna elements operating in
different frequency used
 In fractal antenna coupling
between sharp angles produce
different current paths achieving
multi band operation

12. FRACTAL LOOP ANTENNAS
 Loop antenna needs more space
 Small loop
 low input resistance-
 mismatch to the transmission
line

13. KOCH LOOP
•A koch loop can be used loop antenna
•Perimeter gets increased maintaining the same volume
• less volume required for resonance
• input impedance improved

14. SIREPINSKI MONOPOLE AND DIPOLE
 Multiple bands controlled by scale factors
 Flare angle controls the frequency shift
 Models developed to predict the performance

15. FRACTAL ANTENNA ARRAY
 Antenna array : to improve the gain
 Random fractal used to generate array configuration between periodic and
random
 Low side lobe (feature of periodic array )
 Robust (feature of random array)
 four stage linear Cantor array

16. CONCLUSION
 An overview of fractal antenna theory was presented.
 Small sized, lo profile and low weight antennas can be developed by using
fractal geometries.
 Being in early stage of development more innovations to come in the
future.

18. What is GPS ?
A very precise positioning system
• Developed and maintained by the US Department of Defense
(DOD)
• Satellite Based
* 24 satellites
* 20,200 km high orbit

19. BUT!
Although it is a very precise geographic positioning system
•It is very easy to get youself into trouble
•Why?
•Because you (probably) don’t understand how it works
•And that leads to garbage

20. Characteristics of GPS
• Free
• Precise
• Reliable
• Anytime & anywhere
• All weather
• Unlimited user capacity
Almost!

21. Segments of GPS
1. Space Segment
A constellation of 24 satellites
2. Monitor Station
A network of earth-based facilities
3. Users & Equipment
Source:Trimble

22. Segments of GPS
1. Space Segment
A constellation
of 24 satellites

23. GPS Monitoring Station

24. How GPS Works ………
Uses measurements from 4+ satellites
Distance = travel time x speed of light
Source:Trimble

25. Determining GPS Position
• Suppose the distance from
Satellite A to our position is 11,000
miles
• At this point we could be located
anywhere on the specified sphere
Satellite A
+
• Next, let us take another measurement
from a second satellite, Satellite BSatellite B
+
• Now our position is narrowed down to the
intersection of theses two sphere

26. Satellite C
+
Determining GPS Position
Satellite A
Satellite B
+
+
• Taking another measurement from
a 3rd satellite narrows our position
down even further, to the two points
• So by ranging from 3 satellites we can narrow our
position to just two points in space
• These points are located where the 3rd
sphere cuts through the the intersection of
first two spheres

27. Satellite C
+
How do we decide which one is our true
location?
Satellite A
Satellite B
+
+
• We could make a 4th measurement
from another satellite to determine
the true point
• However, GPS receivers use a 4th satellite to precisely
locate our position
• We can eliminate one of the two
points that gives a ridiculous
answer
• The ridiculous point may be too far
from the earth
OR

28. Determining GPS Position

29. How accurate is GPS?
Depends on some variables
• Design of receiver
• Relative positions of satellites, technically known as PDOP (Position
dilution of precision)
• Postprocessing
• Time spent on measurement

30. GPS Receivers

31. GeoXT Versus Garmin
Mostly used for GIS data collection
Mostly used for
recreational purposes

32. How accurate is GPS?
Depends on some variables
• Design of receiver
• Relative positions of satellites, often known as DOP (Dilution of
Precision)
• Postprocessing
• Time spent on measurement

33. WAAS
• Wide Area Augmentation System.
• It provides FREE GPS differential correction data for visible satellites.
• Developed & operated by the FAA (Federal Aviation Administration) for flight
navigation but it’s available free to GPS users.
• WAAS-enabled receivers can provide sub-meter level accuracy anywhere in
most locations of the US and southern Canada.

34. WAAS
• Differential corrections are computed from ground stations and then
uploaded to geostationary satellites for broadcasting.
• WAAS-enabled GPS receiver automatically uses such correction data to
enhance the positional accuracy.

35. PDOP
Multipath
SNR
Sources of error
Source:Trimble

36. Multipath
• When GPS signals arrive at the receiver
having traveled different paths

37. What is a PDOP?
• Position Dilution of Precision
Good PDOP Poor PDOP

38. SNR (signal-to-noise ratio)
• SNR determines the signal strength relative to noise
• GPS position is degraded if the SNR of one or more satellites
in the constellation falls below certain range
Signal Strength
Indicators

39. Common use of GPS
A. GIS data collection & mapping
B. Navigation
C. Recreation

40. GPS for Navigation

41. GPS for Navigation
• GPS in PDA
are getting popular in car
comes with voice guidance.

42. GPS in Recreation

43. GPS in Farmland

44. Future GPS
A. GPS in USA
B. GLONASS program from Russia
C. GALILEO from European countries