A novel circular slot antenna with two pairs of T-shaped slots is proposed for satisfying WLAN and WiMAX applications simultaneously. The proposed antenna consists of a 50 Ω microstrip feed line with a tuning stub on the top and a circular slot ground plane with an embedded straight strip and two pairs of etched T-shaped slots on the bottom side. By carefully adjusting the length of the straight strip, the proposed antenna can operate in two separate bands. With the use of two pairs of T-shaped slots, a new resonant frequency has been excited, and the impedance bandwidth can be widened. The measured results show that the 10 dB return loss bandwidths of the proposed antenna are 760 MHz (3.18-3.94 GHz) and 1002 MHz (5.05-6.07 GHz), which can cover both 5.2/5.8 GHz WLAN bands and 3.5/5.5 GHz WiMAX bands. The design evolution and parametric study of the proposed antenna are presented to provide information for designing and optimizing such an antenna. Furthermore, good omnidirectional radiation patterns with appreciable antenna gain are obtained over the operating bands.
2. Lee, C.-T. and K.-L. Wong, "Uniplanar printed coupled-fed PIFA with a band-notching slit for WLAN/WiMAX operation in the laptop computer," IEEE Antennas Wirel. Propag. Lett., Vol. 57, 1252-1258, 2009.
3. Nepa, P., G. Manara, A.-A. Serra, and G. Nenna, "Multiband PIFA for WLAN mobile terminals," IEEE Antennas Wirel. Propag. Lett., Vol. 4, 349-350, 2005.
4. Li, B. , Z.-H. Yan, and C. Wang, "Dual rectangular ring with open-ended CPW-fed monopole antenna for WiMAX/WLAN applications," Progress In Electromagnetics Research Letters, Vol. 25, 101-107, 2011.
5. Liu, W.-C. , P.-W. Chen, and C.-C. Liu, "Triple-band planar monopole antenna for DMB/WLAN applications," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 5-6, 653-661, 2010.
6. Panda, J.-R. and R.-S. Kshetrimayum, "A printed 2.4 GHz/5.8 GHz dual-band monopole antenna with a protruding stub in the ground plane for WLAN and RFID applications," Progress In Electromagnetic Research, Vol. 117, 425-434, 2011.
7. Ren, X.-S., Y.-Z. Yin, W. Hu, Y.-Q. Wei, "Compact tri-band rectangular ring patch antenna with asymmetrical strips for WLAN/WiMAX applications," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 13, 1829-1838, 2010.
8. Sze, J.-Y., T.-H., Hu, and T.-J. Chen, "Compact dual-band annular-ring slot antenna with meandered grounded strip," Progress In Electromagnetic Research, Vol. 95, 299-308, 2009.
9. Ren, F.-C. , F.-S. Zhang, J.-H. Bao, B. Chen, and Y.-C. Jiao, "Compact triple-frequency slot antenna for WLAN/WiMAX operations," Progress In Electromagnetics Research Letters, Vol. 26, 21-30, 2011.
10. Chang, T.-N., G.-Y. Shen, and J.-M. Lin, "CPW-fed antenna covering WiMAX 2.5/3.5/5.7 GHz bands," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 2-3, 189-197, 2010.
11. Cai, D.-S. , Z.-Y. Lei, H. Chen, G.-L. Ning, and R.-B. Wang, "Crossed oval-ring slot antenna with triple-band operation for WLAN/WIMAX applications," Progress In Electromagnetics Research Letters, Vol. 27, 141-150, 2011.
12. Sun, X. , G. Zeng, H.-C. Yang, Y. Li, X.-J. Liao, and L. Wang, "Design of an edge-fed quad-band slot antenna for GPS/WIMAX/WLAN applications," Progress In Electromagnetics Research Letters, Vol. 28, 111-120, 2012.