A novel circular arc fractus named Arched Bow-shaped Fractal Curve (ABFC) is originally proposed. Four ABFCs are connected end-to-end, forming so called Arched Bow-shaped Fractal Loop (ABFL). The loop antenna peculiarly presents multiband multimode characteristics with resonance compression. The normal mode, which is pertinent to the loop area and circumference, is found improved with the iterative procedure. Thus, an eight-turned wire helix of small pitch angle (α=3 °) with a circular disc ground called Arched Bow-shaped Fractal Helix (ABFH) antenna is shaped from K2 ABFLs. It can unprecedentedly operate in multiband of axial and off-axial modes with dual-sensed circular polarizations and high gain. Four matched bands (|S11|≤-10 dB) are obtained within 2 GHz-8 GHz, of which f1=2.34 GHz (400 MHz, 17.09%; G=10.63 dBi; RHCP), f2=4.24 GHz (770 MHz, 18.16%; G=12.43 dBi; LHCP), f3=5.48 GHz (300 MHz, 5.47%; G=8.13 dBi; RHCP), and f4=6.98 GHz (960 MHz, 13.75%; G=15.89 dBi; RHCP). The unique multiband multimode property has been theoretically analyzed with illustrations and can be attributed to existence of the fractal boundary, which particularly encloses multiple equivalent loops with considerable areas. These peculiarities make K2 ABFH antenna a very attractive candidate for multiband circularly polarized antennas, especially for space applications, such as spacecrafts communication, remote sensing, and telemetry, where reduction of quantity, height and weight of antennas are urgently wanted. It can also be configured into large array for higher gain service like radars and radio astronomy.
1. Cohen, N., "Fractal antennas: Part 1," Communications Quarterly, 7-22, Aug. 1995.
2. Cohen, N., "Fractal antenna applications in wireless telecommunications," IEEE Electronics Industries Forum of New England, 43-49, May 1997.
3. Mandelbrot, B. B., The Fractal Geometry of Nature, W. H. Freeman, New York, 1983.
4. Werner, D. H., R. L. Haup, and P. L. Werner, "Fractal antenna engineering: The theory and design of fractal antenna arrays," IEEE Antennas and Propagation Magazine, Vol. 41, No. 5, 37-58, Oct. 1999. doi:10.1109/74.801513
5. Gianvitorio, J. and Y. Rahmat, "Fractal antennas: A novel antenna miniaturization technique and applications," IEEE Antennas and Propagation Magazine, Vol. 44, No. 1, 20-36, Feb. 2002. doi:10.1109/74.997888
6. Anguera, J., C. Puente, C. Borja, and J. Soler, "Fractal-shaped antennas: A review," Wiley Encyclopedia of RF and Microwave Engineering, Vol. 2, 1620-1635, Apr. 2005.
7. Liu, Y., S. Gong, and D. Fu, "The advances in development of ractal antennas," Chinese Journal of Radio Science, Vol. 17, No. 1, Feb. 2002.
8. Vinoy, K. J., "Fractal shaped antenna elements for wide and multi band wireless applications,", The Graduate School College of Engineering, The Pennsylvania State University, Aug. 2002.
9. Falconer, K., Fractal Geometry: Mathematical Foundations and Applications, 2nd Edition, John Wiley & Son, Inc., New York, 2003.
10. Baliarda, C. P., J. Romeu, and A. Cardama, "The Koch monopole: A small fractal antenna," IEEE Trans. on Antennas and Propaga., Vol. 48, No. 11, 1773-1781, Nov. 2000. doi:10.1109/8.900236
11. Li, D. T. and J. F. Mao, "A Koch-like sided bow-tie fractal dipole antenna," IEEE Trans. on Antennas and Propaga., Vol. 60, No. 5, 40-49, May 2012. doi:10.1109/MAP.2012.6348117
12. Mirzapour, B. and H. R. Hassani, "Size reduction and bandwidth enhancement of snowflake fractal antenna," IET Microwave Antennas Propag., Vol. 2, No. 2, 180-187, Mar. 2008. doi:10.1049/iet-map:20070133
13. Mahatthanajatuphat, C., S. Saleekaw, and P. Akkaraekthalin, "A rhombic patch monopole antenna with modified Minkowski fractal geometry for UMTS, WLAN, and mobile WiMAX application," Progress In Electromagnetics Research, Vol. 89, 57-74, 2009. doi:10.2528/PIER08111907
14. Gonzalez-Arbesu, J. M., S. Blanch, and J. Romeu, "The Hilbert curve as a small self-resonant monopole from a practical point of view," Microwave and Optical Technology Letters, Vol. 39, No. 1, 45-49, Oct. 2003. doi:10.1002/mop.11122
15. Zhu, J., A. Hoorfar, and N. Engheta, "Bandwidth, cross polarization and feed-point characteristics of matched Hilbert antennas," IEEE Antennas and Wireless Propagation Letters, Vol. 2, No. 1, 2-5, Jan. 2003. doi:10.1109/LAWP.2003.810765
16. Werner, D. H., W. Kuhirun, and P. L. Werner, "The Peano-Gosper fractal array," IEEE Trans. on Antennas and Propaga., Vol. 51, No. 8, 2063-2072, Aug. 2003. doi:10.1109/TAP.2003.815411
17. Zhu, J., A. Hoorfar, and N. Engheta, "Peano antennas," IEEE Antennas and Wireless Propagation Letters, Vol. 3, 71-74, Jan. 2004.
18. Puente, C., J. Romeu, R. Pous, and A. Cardama, "On the behavior of the Sierpinski multiband fractal antenna," IEEE Trans. on Antennas and Propaga., Vol. 46, 517-524, Apr. 1998. doi:10.1109/8.664115
19. Oraizi, H. and S. Hedayati, "Miniaturized UWB monopole microstrip antenna design by the combination of Giusepe Peano and Sierpinski carpet fractals," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 67-70, 2011. doi:10.1109/LAWP.2011.2109030
20. Kumar, R. and P. N. Chaubey, "On the design of inscribed pentagonal-cut fractal antenna for ultra-wideband applications," Microwave and Optical Technology Letters, Vol. 53, No. 12, Dec. 2011. doi:10.1002/mop.26415
21. Li, D. T. and J. F. Mao, "Koch-like sided Sierpinski gasket multifractal dipole antenna," Progress In Electromagnetics Research, Vol. 26, 399-427, 2012. doi:10.2528/PIER12010404
22. Li, D. T. and J. F. Mao, "Sierpinskized Koch-like sided multifractal dipole antenna," Progress In Electromagnetics Research, Vol. 13, 207-224, 2012.
23. Kraus, J. D. and R. J. Marhefka, Antennas: For All Application, 3rd Edition, McGraw-Hill, Nov. 2001.
25. Kraus, J. D. and J. C. Williamson, "Characteristics of helical antennas radiating in the axial mode," Journal of Applied Physics, Vol. 19, No. 1, 87-96, Jan. 1948. doi:10.1063/1.1697878
26. Yousaf, J., M. Amin, and S. Iqbal, "Design of circularly polarized omnidirectional bifilar helix antennas with optimum wide axial ratio beamwidth," Progress In Electromagnetics Research C, Vol. 39, 119-132, 2013.
27. Amin, M., J. Yousaf, and M. K. Amin, "Terrestrial mode quadrifilar helix antenna," Progress In Electromagnetics Research Letters, Vol. 27, 179-187, 2011. doi:10.2528/PIERL11081202
28. Weeratumanoon, E., "Helical antennas with truncated spherical geometry,", The Virginia Polytechnic Institute and State University, Blacksburg, Virginia, Jan. 27, 2000.
29. Gharibi, H. and F. H. Kashani, "Design of a wideband monopulse antenna using four conical helix antennas," Progress In Electromagnetics Research Letters, Vol. 29, 25-33, 2012. doi:10.2528/PIERL11111106
30. Best, S. R., "The fractal loop antenna: A comparison of fractal and non-fractal geometries," IEEE Antennas and Propagation Society International Symposium, Vol. 3, 146-149, Jul. 2001.