In this paper, a wide-slot triple band antenna fed by a coplanar waveguide (CPW) for WLAN/WiMAX applications is proposed. The antenna mainly comprises a ground with a wide square slot in the center, a rectangular feeding strip and two pairs of planar inverted L strips (PIL) connecting with the slotted ground. By introducing the two pairs of PIL's, three resonant frequencies, 2.4/5.5 GHz for WLAN, and 3.5 GHz for WiMAX, are excited. Prototypes of the antenna are fabricated and tested. The simulated and measured results show that the proposed antenna has three good impedance bandwidths (S11 better than -10 dB) of 300 MHz (about 12.6% centered at 2.39 GHz), 280 MHz (about 8% centered at 3.49 GHz) and 790 MHz (about 14.5% centered at 5.43 GHz), which make it easily cover the required bandwidths for WLAN band (2.4--2.48 GHz, 5.15--5.35 GHz, and 5.725--5.825 GHz) and WiMAX (3.4--3.6 GHz) applications. Moreover, the obtained radiation patterns demonstrate that the proposed antenna has figure-eight patterns in E-plane, and is omni-directional in H-plane. The gains of the antenna at operation bands are stable.
2. Elsadek, H. and D. M. Nashaat, "Quad band compact size trapezoidal PIFA antenna," Journal of Electromagnetic Waves and Applications, Vol. 21, No. 7, 865-876, 2007.
3. Pan, B, R. L. Li, J. Papapolymerou, J. Laskar, and M. M. Tentzeris, "Low-profile broadband and dual-frequency two-strip planar monopole antennas," IEEE Antennas and Propagation Society International Symposium, 2665-2668, 2006.
4. Lin, S.-J. and J.-S. Row, "Monopolar patch antenna with dual-band and wideband operations," IEEE Transactions on Antennas and Propagation, Vol. 56, 900-903, 2008.
5. Deepu, V., K. R. Rohith, J. Manoj, M. N. Suma, K. Vasudevan, C. K. Aanandan, and P. Mohanan, "Compact uniplanar antenna for WLAN applications," IEEE Electronic Letters, Vol. 43, 70-72, 2007.
6. Wang, F. J. and J.-S. Zhang, "Wideband cavity-backed patch antenna for PCS/IMT2000/2.4 GHz WLAN," Progress In Electromagnetics Research, Vol. 74, 39-46, 2007.
7. Liu, W. C. and H.-J. Liu, "Miniaturized asymmetrical CPW-FED meandered strip antenna for triple-band operation," Journal of Electromagnetic Waves and Applications, Vol. 21, No. 8, 1089-1097, 2007.
8. Chiang, M.-J., J.-Y. Sze, and G.-F. Cheng, "A compact dual-band planar slot antenna incorporating embedded metal strips for WLAN application," 39th European Microwave Conference, 221-224, 2009.
9. Lee, Y.-C. and J.-S. Sun, "Compact printed slot antennas for wireless dual-band multi-band operations," Progress In Electromagnetics Research, Vol. 88, 289-305, 2008.
10. Jan, J.-Y. and J.-W. Su, "Bandwidth enhancement of a printed wide-slot antenna with a rotated slot," IEEE Transactions on Antennas and Propagation, Vol. 53, No. 6, 2111-2114, 2005.
11. Sze, J.-Y., C.-I. G. Hsu, and S.-C. Hsu, "Design of a compact dual-band annular-ring slot antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 6, 423-426, 2007.
12. Sze, J.-Y., C.-I. G. Hsu, and S.-C. Hsu, "Dual-broadband multi-standard printed slot antenna with a composite back-patch," IET Microwaves Antennas Propagation, Vol. 2, No. 2, 205-209, 2008.
13. Sze, J.-Y., T.-H. Hu, and T.-J. Chen, "Compact dual-band annular-ring slot antenna with meandered grounded strip," Progress In Electromagnetics Research, Vol. 95, 299-308, 2009.
14. Xiong, J. P., L. Liu, X. M. Wang, J. Chen, and Y. L. Zhao, "Dual-band printed bent slots antenna for WLAN applications," Journal of Electromagnetic Waves and Applications, Vol. 22, No. 11-12, 1509-1515, 2008.
15. Eldek, A. A., A. Z. Elsherbeni, and C. E. Smith, "Dual wideband square slot antenna with a u-shaped printed tuning stub for personal wireless communication systems," Progress In Electromagnetics Research, Vol. 53, 319-333, 2005.
16. Chen, S.-Y., P.-H. Wang, and P. Hsu, "Uniplanar log-periodic slot antenna fed by a CPW for UWB applications," IEEE Antennas and Wireless Propagation Letters, Vol. 5, 256-259, 2006.
17. Song, Y., Y.-C. Jiao, G. Zhao, and F.-S. Zhang, "Multi-band CPW-fed triangle-shaped monopole antenna for wireless applications," Progress In Electromagnetics Research, Vol. 70, 329-336, 2007.