Submitted by
NEERAJ MANI TRIPATHI

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ABSTRACT
A detailed study on the various next generation nature inspired geometry antennas
i.e. fractal antennas is performed. Mainly four types of printed fractal antennas i.e.
Sierpinski Carpet, Quasi Koch Fractal, Mix fractal and Sierpinski Gasket Fractal
are designed using 3D FEM based solver (Ansoft HFSS), which are basically
variants of Patch antenna. Maximum iteration is three and these antennas are fed
using three basic techniques Transformer Feed, Inset Feed and Probe Feed. All four
antennas are fabricated on low loss substrate RT/Duroid 5880. The return loss,
Gain, Bandwidth and Radiation Patterns of these antennas are measured using
Agilent E8363BPNA series (10MHz to 40 GHz) network analyzer, CATR(compact
antenna test range) and other facilities. Results are compared with reference
Microstrip Patch antenna.
Out of four fractals antennas, Quasi Koch Fractal Antenna have satisfactory
performance and Mixed Fractal Antenna have excellent performance. For Quasi
Koch Fractal Antenna, resonant frequency is reduced and sufficient return loss,
bandwidth, gain and efficiency is observed. Also, for Mixed Fractal Antenna,
resonant frequency is reduced and excellent return loss, good bandwidth, moderate
gain and very good efficiency is achieved in both simulation and measurement.
Other two antennas have poor performance. These results shows the advantage of
using fractal geometry in antennas.
INTRODUCTION
1.1 GENERAL
In modern era of wireless communication, satellite communication and advanced
military systems, antennas of higher performance are always in demand. There is
always is a quest for new antennas of higher gain, higher bandwidth, reduced size
and desired characteristics. This quest has led researchers in various directions.
Currently due to advancement in the simulators, enables researchers to design such
antennas which are very difficult to analyze and one of them is nature inspired
geometries commonly known as fractal antennas. These geometries are available
from past many years but were very difficult to analyze. But now, these kinds of
antennas are being under limelight.
It have already proved that fractal shapes have their own unique characteristics that
improves antenna performance without degrading antenna properties. This thesis
presents the study, designing, fabrication, testing and comparison of different types
of fractal antennas.
1.2 TOPICS COVERED
• Fractal Antennas and its types
• Designing of four types of Fractal antennas
• Measurement of the antennas properties.
• Comparison the measurement and simulation results.