This paper presents a novel compact Koch snowflake fractal ring based Dielectric Resonator Antenna (DRA) for ultra wideband application. Firstly, Koch snowflake fractal geometry is implemented on the conventional Cylindrical Dielectric Resonator Antenna (CDRA). Further, the performance of the DRA is enhanced by fractal ring created on the snowflake geometry. With the application of the fractal and the fractal ring geometry, the Q-factor of DRA is reduced, thus the bandwidth of DRA is increased. The proposed antenna offers a wide impedance bandwidth of 90% ranging from 4.7 GHz-12.4 GHz. The effect of the fractal geometry enhances the gain of DRA. The proposed antenna achieves radiation efficiency more than 78%, throughout the bandwidth. Interestingly, the proposed configuration reduces the DRA volume by 76.63% with reduced volume of 7.91 cm3. The experimental verification of the proposed structure shows good agreement between simulated and measured results.
1. Long, S. A., M. W. McAllister, and L. C. Shen, "The resonant cylindrical dielectric cavity antenna," IEEE Transactions on Antennas and Propagation, Vol. 31, No. 3, 406-412, March 1983. doi:10.1109/TAP.1983.1143080
2. Petosa, A., Dielectric Resonator Antenna Handbook, Artech House, Norwood, MA, USA, 2007.
3. McAllister, M. W. and S. A. Long, "Rectangular dielectric resonator antenna," IET Electronics Letters, Vol. 19, No. 6, 218-219, Mar. 1983. doi:10.1049/el:19830150
4. McAllister, M. W. and S. A. Long, "Resonant hemispherical dielectric antenna," IET Electronics Letters, Vol. 20, 657-659, Aug. 1984. doi:10.1049/el:19840450
5. Mandelbrot, B., The Fractal Geometry of Nature, W. H. Freeman and Company, New York, 1977.
6. Dhar, S., R. Ghatak, B. Gupta, and D. R. Poddar, "A wideband Minkowski fractal dielectric resonator antenna," IEEE Trans. Antennas Propag., Vol. 61, No. 6, 2895-2903, Jun. 2013. doi:10.1109/TAP.2013.2251596
7. Mukherjee, B., P. Patel, and J. Mukherjee, "Hemispherical dielectric resonator antenna based on Apollonian Gasket of circles — A fractal approach," IEEE Trans. Antennas Propag., Vol. 62, No. 1, 40-47, Jan. 2014. doi:10.1109/TAP.2013.2287011
8. Majeed, A. H., A. S. Abdullah, K. H. Sayidmarie, R. A. Abd-Alhameed, F. Elmegri, and J. M. Noras, "Balanced dual-segment cylindrical dielectric resonator antennas for ultra-wideband applications," IET Microwaves, Antennas and Propagation, Vol. 9, No. 13, 1478-1486, 2015. doi:10.1049/iet-map.2015.0221
9. Ozzaim, C., F. Ustuner, and N. Tarim, "Stacked conical ring dielectric resonator antenna excited by a monopole for improved ultra-wide bandwidth," IEEE Trans. Antennas Propag., Vol. 61, No. 3, Mar. 2013. doi:10.1109/TAP.2012.2227442
10. Sharma, A. and R. K. Gangwar, "Hybrid two segments ring dielectric resonator antenna for ultra wideband application," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 26, No. 1, 47-53, Jan. 2016. doi:10.1002/mmce.20937
11. Guha, D., B. Gupta, and Y. M. M. Antar, "Hybrid monopole DRAs using hemispherical/conicalshaped dielectric ring resonators: Improved ultra wideband designs," IEEE Trans. Antennas Propag., Vol. 60, 393-398, 2012. doi:10.1109/TAP.2011.2167948
12. Majeed, A. H., A. S. Abdullah, K. H. Sayidmarie, R. A. Abd-Alhameed, F. Elmegri, and J. M. Noras, "Compact dielectric resonator antenna with band-notched characteristics for ultrawideband applications," Progress In Electromagnetics Research C, Vol. 57, 137-148, 2015. doi:10.2528/PIERC15022102
13. Gangwar, R. K., S. P. Singh, and D. Kumar, "A modified fractal rectangular curve dielectric resonator antenna for WiMAX application," Progress In Electromagnetic Research C, Vol. 12, 37-51, 2010. doi:10.2528/PIERC09111303
14. Addison, P. S., Fractals and Chaos — An Illustrated Course, IoP Publishing, Institute of Physics, 1997. doi:10.1201/9780849384431
15. Barnsley, M. F., Fractals Everywhere, 2 Ed., Morgan Kaufmann, 2000.
16. Zhu, Z. W. and B. G. Jia, "On the lower bound of the Hausdorff measure of the Koch curve," Acta Mathematica Sinica, Vol. 19, No. 4, 715-728, Oct. 2003. doi:10.1007/s10114-003-0310-2
17. Kajfez, D., A. W. Glisson, and J. James, "Computed modal field distribution for isolated dielectric resonators," IEEE Trans. Microwave Theory Tech., Vol. 32, 1609-1616, Dec. 1984. doi:10.1109/TMTT.1984.1132900
18. De Medeiros, J. L. G., W. C. de Araujo, A. G. d’Assuncao, L. M. de Mendonca, and J. B. L. de Oliveira, "Investigation on ZPT ceramics applied as dielectric resonator antenna for ultra-wideband systems," Microwave and Optical Technology Letters, Vol. 55, No. 6, 1352-1355, Jun. 2013. doi:10.1002/mop.27576
19. Pozar, M., Microwave Engineering, 2 Ed., John Wiley & Sons, 2004.
20. Kong, J. A., Electromagnetic Wave Theory, Wiley Interscience, 1990.
22. Waldron, R. A., "Perturbation theory of resonant cavities," roc. IEE — Part C Monogrraphs, Vol. 107, 272-274, 1960. doi:10.1049/pi-c.1960.0041
23. Chaudhary, R. K., K. V. Srivastava, and A. Biswas, "Multi-band cylindrical dielectric resonator antenna using permittivity variation in azimuth direction," Progress In Electromagnetics Research C, Vol. 59, 11-20, 2015. doi:10.2528/PIERC15070708
24. Babik, G. B., C. Di Nallo, and A. Faraone, "Multimode dielectric resonator antenna of very high permittivity," IEEE Antennas and Propagation Society International Symposium, Vol. 2, 1383-1386, Monterey, CA, 2004.
25. Mongia, R. K. and P. Bhartia, "Dielectric resonator antennas — A review and general design relations for resonant frequency and bandwidth," Int. J. of Microwave Millimeter-Wave Eng., Vol. 4, No. 3, 230-247, Jul. 1994. doi:10.1002/mmce.4570040304
26. Wannagot, G. A., A. Macqueen, R. E. Cozzolino, and L. J. Reading, "Variable gain and variable beam width antenna (the hinged antenna),", U.S. patent 6774854 B2, Aug. 10, 2004.
27. Mohebbi, B. B., "Variable gain antenna for cellular repeater,", U.S. patent 20080299897 A1, Dec. 4, 2008.
28. Balanis, C. A., Antenna Theory, Analysis and Design, 3 Ed., Wiley, New York, NY, USA, 2005.