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FRACTAL ANTENNAS –A NOVEL MINIATURIZATION TECHNIQUE FOR WIRELESS COMMUNICATIONS

FRACTAL ANTENNAS –A NOVEL MINIATURIZATION TECHNIQUE FOR WIRELESS COMMUNICATIONS. BY. A. ANCY STEFFINA DEVISREE II ECE VVCOE. OBJECTIVE. To provide a study of different fractal antenna with an overview of recent developments. FRACTAL ANTENNA – AN INTRODUCTION.

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FRACTAL ANTENNAS –A NOVEL MINIATURIZATION TECHNIQUE FOR WIRELESS COMMUNICATIONS

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  1. FRACTAL ANTENNAS –A NOVEL MINIATURIZATION TECHNIQUE FOR WIRELESS COMMUNICATIONS BY A. ANCY STEFFINA DEVISREE II ECE VVCOE

  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 four iteration Koch fractal A three iteration Sirepinski 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

  17. THANK YOU

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