In this paper, an ultra wideband antenna employing a defected ground structure is presented. The radiating element is a circular patch on which a fractal based geometry is inscribed in the form of slots and excited by a tapered feed-line for impedance matching. The antenna has an impedance bandwidth of 8.2 GHz (117% at centre frequency of 7 GHz) and a peak gain around 6 dB. To improve the impedance bandwidth and gain, a Swastika shape Electromagnetic band gap (EBG) structure is proposed. The unit cell of the proposed EBG has a compact size of 3 mm × 3 mm and is obtained by introducing discontinuities in the outer ring of the Cross-Hair type EBG. The stop band (-20 dB) achieved with this EBG is 3.6 GHz (7.5 GHz-11.1 GHz) which is 1.6 GHz more than that achieved by a standard mushroom-type EBG of the same size and same number of elements. After application of the proposed EBG, there is an improvement of 12% in the impedance bandwidth while the peak gain increases by about 2-3 dB. The radiation of the antenna shows a dumb-bell shaped pattern in the E-plane and Omni-directional pattern in the H-plane. All the measured results are in good agreement with simulated results.
2. Azim, R., M. T. Islam, and N. Misran, "Compact tapered-shape slot antenna for UWB applications," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 1190-1193, 2011.
doi:10.1109/LAWP.2011.2172181
3. Rama Krishna, R. V. S. and K. Raj, "Design of temple shape slot antenna for ultra wideband applications," Progress In Electromagnetics Research B , Vol. 47, 405-421, 2013.
4. Chen, H.-D., "Broadband CPW-fed square slot antennas with a widened tuning stub," IEEE Transactions on Antennas and Propagation , Vol. 51, No. 8, 1982-1986, 2003.
doi:10.1109/TAP.2003.814747
5. Dastranj, A., A. Imani, and M. Naser-Moghaddasi, "Printed wide-slot antenna for wideband applications," IEEE Transactions on Antennas and Propagation, Vol. 56, No. 10, 3097-3102, 2008.
doi:10.1109/TAP.2008.929459
6. Fallahi, R., A. A. Kalteh, and M. G. Roozbahani, "A novel UWB elliptical slot antenna with band-notched characteristics," Progress In Electromagnetics Research, Vol. 82, 127-136, 2008.
doi:10.2528/PIER08022603
7. Bahl, I. J. and P. Bhartia, Microstrip Antennas, Artech House, Dedham, MA, 1980.
8. Kumar, G. and K. P. Ray, Broadband Microstrip Antennas, Artech House, 2003.
9. Balanis, C. A., Antenna Theory Analysis and Design, Wiley Publication, 2005.
10. Garg, R., P. Bhartia, I. J. Bahl, and A. Ittipiboon, Microstrip Antenna Design Handbook, Artech House, 2001.
11. Sievenpiper, D., "High-impedance electromagnetic surfaces," Ph.D. Dissertation, Department of Electrical Engineering, University of California at Los Angeles, 1999.
12. Lee, Y., J. Yeo, K. Ko, Y. Lee, W. Park, and R. Mittra, "A novel design technique for control of defect frequencies of an electromagnetic band gap (EBG) cover for dualband directivity enhancement," Microwave and Optical Technology Letters , Vol. 42, No. 1, 25-31, 2004.
doi:10.1002/mop.20196
13. Pirhadi, A., F. Keshmiri, M. Hakkak, and M. Tayarani, "Analysis and design of dual band high directive EBG resonator antenna using square loop FSS as superstrate layer," Progress In magnetics Research , Vol. 70, 1-20, 2007.
14. Alam, M. S., M. T. Islam, and N. Misran, "A novel compact split ring slotted electromagnetic bandgap structure for microstrip patch antenna performance enhancement," Progress In Electromagnetics Research , Vol. 130, 389-409, 2012.
15. Qu, D., L. Shafai, and A. Foroozesh, "Improving microstrip patch antenna performance using EBG substrates," IEE Proceedings --- Microwaves, Antennas and Propagation, Vol. 153, No. 6, 558-563, 2006.
doi:10.1049/ip-map:20060015
16. Sievenpiper, D., L. Zhang, R. F. Jimenez Broas, N. G. Alex-opoulos, and E. Yablonovitch, "High-impedance electromagnetic surfaces with a forbidden frequency band," IEEE Trans. on Microwave Theory and Techn., Vol. 47, 2059-2074, 1999.
17. Gupta, R. K. and J. Mukherjee, "Effect of superstrate material on a high-gain antenna using array of parasitic patches," Microwave and Optical Technology Letters , Vol. 52, No. 1, 2010.
18. Xu, F., Z.-X. Wang, X. Chen, and X.-A. Wang, "Dual band-notched UWB antenna based on spiral electromagnetic-bandgap structure," Progress In Electromagnetics Research B, Vol. 39, 393-409, 2012.
19. Yazdi, M. and N. Komjani, "Design of a band-notched UWB monopole antenna by means of an EBG structure," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 170-173, 2011.
20. Weily , A. R., K. P. Esselle, and B. C. Sanders, "Dual resonator 1-D EBG antenna with slot array feed for improved radiation bandwidth," IET Microw. Antennas Propag., Vol. 1, 198-203, 2007.
21. Gujral, M., J. L.-W. Li, T. Yuan, and C.-W. Qiu, "Bandwidth improvement of microstrip antenna array using dummy EBG pattern on feedline," Progress In Electromagnetic Research , Vol. 127, 79-92, 2012.
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