In this paper, a novel compact hexagonal shaped ultra-wideband multiple-input multiple-output (UWB-MIMO) Koch fractal antenna is designed with penta-band rejection characteristics for portable devices. The antenna rejects the C-band downlink frequency from 3.7-4 GHz, the C-band uplink frequency from 5.75-6.05 GHz and the satellite bands from 7.45 to 8.4 GHz. The band 7.45-7.55 GHz is used by the meteorological satellite service for the geostationary satellite services. The band 7.75-7.9 GHz is used by the meteorological satellite service for non-geostationary satellite services. The band 8.025-8.4 GHz is used by the Earth exploration satellites for geostationary satellite services. The C-band and satellite bands interfere with the UWB and have been rejected using a band reject filter. A spiral shaped slot is introduced inside the fractal hexagonal monopole to introduce band reject characteristics. The band suppression and widening of the impedance bandwidth are achieved by using defected ground structures. The antenna has wideband impedance matching with S11 < -10 dB in the UWB frequency range from 3.1 to 13.6 GHz and has a low mutual coupling with S21 < -19 dB. The antenna has very low envelope correlation coefficient of less than 0.17 and low capacity loss of 0.254, which proves that the MIMO antenna shows good diversity performance.
"A Penta-Band Reject Inside Cut Koch Fractal Hexagonal Monopole UWB MIMO Antenna for Portable Devices," Progress In Electromagnetics Research C,
Vol. 82, 225-235, 2018. doi:10.2528/PIERC18020604
1. Jetti, C. R. and V. R. Nandanavanam, "Trident-shape strip loaded dual band-notched UWB MIMO antenna for portable device applications," AEU-International Journal of Electronics and Communications, Vol. 83, 11-21, 2018. doi:10.1016/j.aeue.2017.08.021
2. Rajkumar, S., N. V. Sivaraman, S. Murali, and K. T. Selvan, "Heptaband swastik arm antenna for MIMO applications," IET Microwaves, Antennas & Propagation, Vol. 11, No. 9, 1255-1261, 2017. doi:10.1049/iet-map.2016.1098
3. Yadav, A., S. Agarwal, and R. P. Yadav, "SRR and S-shape slot loaded triple band notched UWB antenna," AEU-International Journal of Electronics and Communications, Vol. 79, 192-198, 2017. doi:10.1016/j.aeue.2017.06.003
4. Yang, B. and S. Qu, "A compact integrated Bluetooth UWB dual-band notch antenna for automotive communications," AEU-International Journal of Electronics and Communications, Vol. 80, 104-113, 2018.
5. Atallah, H. A., A. B. Abdel-Rahman, K. Yoshitomi, and R. K. Pokharel, "CPW-Fed UWB antenna with sharp and high rejection multiple notched bands using stub loaded meander line resonator," AEU-International Journal of Electronics and Communications, Vol. 83, 22-31, 2018. doi:10.1016/j.aeue.2017.08.022
6. Rajkumar, S., K. T. Selvan, and P. H. Rao, "Compact two-element UWB fractal monopole MIMO antenna using T-shaped reflecting stub for high isolation ," IEEE MTT-S International Microwave and RF Conference, 348-351, 2015.
7. Tripathi, S., A. Mohan, and S. Yadav, "A compact Koch fractal UWB MIMO antenna with WLAN band-rejection," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 1565-1568, 2015. doi:10.1109/LAWP.2015.2412659
8. Tripathi, S., A. Mohan, and S. Yadav, "Hexagonal fractal ultra-wideband antenna using Koch geometry with bandwidth enhancement," IET Microwaves, Antennas & Propagation, Vol. 8, No. 15, 1445-1450, 2014. doi:10.1049/iet-map.2014.0326
9. Tripathi, S., A. Mohan, and S. Yadav, "A compact octagonal shaped fractal UWB MIMO antenna with 5.5 GHz band-notch characteristics," IEEE International Microwave and RF Conference (IMaRC) , 178-181, IEEE, 2014. doi:10.1109/IMaRC.2014.7039002
10. Zhang, J.-Y., F. Zhang, W.-P. Tian, and Y.-L. Luo, "ACS-fed UWB-MIMO antenna with shared radiator," Electronics Letters, Vol. 51, No. 17, 1301-1302, 2015. doi:10.1049/el.2015.1327
11. Luo, C.-M., J.-S. Hong, and L.-L. Zhong, "Isolation enhancement of a very compact UWB-MIMO slot antenna with two defected ground structures," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 1766-1769, 2015. doi:10.1109/LAWP.2015.2423318
12. Liu, L., S. W. Cheung, and T. I. Yuk, "Compact MIMO antenna for portable UWB applications with band-notched characteristic," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 5, 1917-1924, 2015. doi:10.1109/TAP.2015.2406892
13. Pele, I., A. Chousseaud, and S. Toutain, "Simultaneous modeling of impedance and radiation pattern antenna for UWB pulse modulation," Antennas and Propagation Society International Symposium, Vol. 2, 1871-1874, IEEE, 2004.
14. Zhou, H.-J., B.-H. Sun, Q.-Z. Liu, and J.-Y. Deng, "Implementation and investigation of U-shaped aperture UWB antenna with dual band-notched characteristics," Electronics Letters, Vol. 44, No. 24, 1387-1388, 2008. doi:10.1049/el:20082661
15. Mewara, H. S., D. Jhanwar, M. M. Sharma, and J. K. Deegwal, "A printed monopole ellipzoidal UWB antenna with four band rejection characteristics," AEU-International Journal of Electronics and Communications, Vol. 83, 222-232, 2018. doi:10.1016/j.aeue.2017.08.043
16. Khan, M. S., A.-D. Capobianco, A. I. Najam, I. Shoaib, E. Autizi, and M. F. Shafique, "Compact ultra-wideband diversity antenna with a floating parasitic digitated decoupling structure," IET Microwaves, Antennas & Propagation, Vol. 8, No. 10, 747-753, 2014. doi:10.1049/iet-map.2013.0672
17. Gulam Nabi Alsath, M. and M. Kanagasabai, "Compact UWB monopole antenna for automotive communications," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 9, 4204-4208, 2015. doi:10.1109/TAP.2015.2447006
18. Yu, Y., X. Liu, Z. Gu, and L. Yi, "A compact printed monopole array with neutralization line for UWB applications," IEEE International Symposium on Antennas and Propagation (APSURSI), 1779-1780, 2016. doi:10.1109/APS.2016.7696596
19. Puente, C., J. Romeu, R. Pous, J. Ramis, and A. Hijazo, "Small but long Koch fractal monopole," Electronics Letters, Vol. 34, No. 1, 9-10, 1998. doi:10.1049/el:19980114
20. Best, S. R., "On the performance properties of the Koch fractal and other bent wire monopoles," IEEE Transactions on Antennas and Propagation, Vol. 51, No. 6, 1292-1300, 2003. doi:10.1109/TAP.2003.812257
21. Anagnostou, D. E., J. Papapolymerou, C. G. Christodoulou, and M. Tentzeris, "A small planar logperiodic Koch-dipole antenna (LPKDA)," IEEE Antennas and Propagation Society International Symposium, 3685-3688, 2006.
22. Anagnostou, D., M. T. Chryssomallis, J. C. Lyke, and C. G. Christodoulou, "A CPW koch dipole slot antenna," IEEE Topical Conference on Wireless Communication Technology, 337, 2003. doi:10.1109/WCT.2003.1321548
23. Best, S. R., "On the resonant properties of the Koch fractal and other wire monopole antennas," IEEE Antennas and Wireless Propagation Letters, Vol. 1, No. 1, 74-76, 2002. doi:10.1109/LAWP.2002.802550