An octagonal shape patch antenna with switchable inverted L-shaped slotted ground is designed for frequency band reconfigurable and experimentally validated. The antenna is capable of frequency band switching at five different states including an ultra wideband (UWB) state, two narrowband states and a dual-band state by using RF switching element p-i-n diodes. In the case of ultrawide band (UWB) state, the proposed antenna operates over impedance bandwidth of 141% (2.87-16.56 GHz) under simulation and 139% (2.85-15.85 GHz) in measurement with return loss S11 < -10 dB. For two narrowband states, 10 dB impedance bandwidth achieved is 16% (5.05-5.91 GHz) and 11% (8.76-9.80 GHz) under simulation and 14% (5.01-5.79 GHz) and 10% (8.68-9.69 GHz) in measurement, respectively. For the dual band state, 10 dB impedance bandwidth of 2.21-2.52 GHz (13%) & 5.07-5.89 GHz (15%) and 2.18-2.52 GHz (14%) & 8.78-9.71 GHz (10%) under simulation and 2.20-2.50 GHz (12%) & 5.05-5.90 GHz (15%) and 2.19-2.50 GHz (13%) & 8.70-9.60 GHz (9%) in measurement with return loss S11 < -10 dB. The proposed antenna is capable to serve in different wireless communication applications such as WLAN [802.11b/g/n (2.4-2.48 GHz), 802.11a/h/j/n (5.2 GHz), ISM band (2.4-2.5 GHz)], Bluetooth (2400-2484 MHz), WiMAX (2.3-2.4 & 5.15-5.85 GHz), WiFi (2.40-2.48, 5.15-5.85 GHz) and UWB (3.1-10.6 GHz). It also works at 9.2 GHz where airborne radar applications are found. Next, the antenna gain is improved with the help of a circular loop frequency selective surface (FSS) and a PEC (perfect electric conductor) sheet. Measured peak gain represents average improvements about 4 dB-5 dB over the UWB band. Experimental results seem in good agreement with the simulated ones of the proposed antenna with and without the frequency selective surface.
2. FCC (Federal Communications Commission), First Report and Order, Feb. 14, 2002.
3. Li, R. L., T. Wu, S. Y. Eom, S. S. Myoung, K. Lim, J. Laskar, S. I. Jeon, and M. M. Tentzeris, "Switchable quad-band antennas for cognitive radio base station applications," IEEE Trans. Antennas Propagation, Vol. 58, No. 5, 1468-1476, May 2010.
4. Mahmoud, S. F. and A. F. Sheta, "A widely tunable compact patch antenna," IEEE Antennas Wireless Propagation Letter, Vol. 7, 40-42, 2008.
5. Huang, C. T. and T. Y. Han, "Reconfigurable monopolar patch antenna," Electron Lett., Vol. 46, No. 3, 199-200, Feb. 2010.
6. Gardner, P., M. R. Hamid, P. S. Hall, and F. Ghanem, "Switched-band Vivaldi antenna," IEEE Trans. Antennas Propagation, Vol. 59, No. 5, 1472-1480, May 2011.
7. Li, R. L., G. P. Jin, and D. L. Zhang, "Optically controlled reconfigurable antenna for cognitive radio applications," Electron Lett., Vol. 47, No. 17, 948-950, Aug. 2011.
8. Gardner, P., M. R. Hamid, P. S. Hall, and F. Ghanem, "Vivaldi antenna with integrated switchable band pass resonator," IEEE Trans. Antennas Propagation, Vol. 59, No. 11, 4008-4015, Nov. 2011.
9. Ghafouri-Shiraz, H. and A. Tariq, "Frequency-reconfigurable monopole antennas," IEEE Trans. Antennas Propagation, Vol. 60, No. 1, 44-50, Jan. 2012.
10. Gardner, P., J. R. Kelly, and P. S. Hall, "Integrated wide-narrow band antenna for switched operation," Processing IEEE EuCAP, 3757-3760, Berlin, Germany, 2009.
11. Boudaghi, H., M. Azarmanesh, and M. Mehranpour, "A frequency-reconfigurable monopole antenna using switchable slotted ground structure," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 2012.
12. Dushmantha, N., P. Thalakotuna, L. Matekovits, M. Heimlich, K. P. Esselle, and S. G. Hay, "Active switching devices in a tunable EBG structure: Placement strategies and modeling," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 11-12, 1740-1751, 2011.
13. Dushmantha, N., P. Thalakotuna, K. P. Esselle, L. Matekovits, M. Heimlich, and S. G. Hay, "Changing the electromagnetic bandgap and stopbands in a multistate periodic circuit," Microwave and Optical Technology Letters (MOTL), Vol. 55, No. 8, 1871-1874, Aug. 2013.
14. Kushwaha, N. and R. Kumar, "Design of slotted ground hexagonal microstrip patch antenna and gain improvement with FSS screen," Progress In Electromagnetics Research B, Vol. 51, 177-199, 2013.
15. Alpha Industries, "ALPHA-6355 beamlead PIN diode,", Data sheet, [Online]. Available: http://www.datasheetarchive.com/ALPHA/PIN diode 6355-datasheet.html.
16. Computer Simulation Technology - CST (Microwave Studio MWS), Version-2014.
17. Ray, K. P. and G. Kumar, "Determination of resonant frequency of microstrip antennas," Microw. Opt. Technol. Lett., Vol. 23, 114-117, 1999.
18. Langley, R. J. and E. A. Parker, "Equivalent-circuit model for arrays of square loops," Electron Lett., Vol. 18, 294-296, 1982.
19. Chung, Y.-C., K.-W. Lee, I.-P. Hong, M.-G. Lee, H.-J. Chun, and J.-G. Yook, "Simple prediction of FSS radome transmission characteristics using an FSS equivalent circuit model," IEICE Electron. Expr., Vol. 8, No. 2, 89-95, 2011.
20. Kushwaha, N., R. Kumar, R. V. S. Ram Krishna, and T. Oli, "Design and analysis of new compact UWB frequency selective surface and its equivalent circuit," Progress In Electromagnetics Research C, Vol. 46, 31-39, 2014.