A new antenna with dual-band circular polarization for the reception of WiMAX and WLAN is presented in this article. The circular polarization is achieved by a symmetrical U-slot together with an L-slot. The width of the signal strip is narrowed at the end of the feed point to widen the 3-dB axial ratio (AR) bandwidth and create a good impedance matching for the proposed antenna. A parametric study is conducted using a commercial simulation software based on the method of moments, and the antenna prototype is constructed and measured for providing the simulation validation. Experimental results show that the measured AR bandwidths are about 16.6% and 16.2% with respect to the center frequency at 3.5GHz and 5.3GHz. The radiation characteristics of the proposed antenna are also presented.
2. Du, S., Q.-X. Chu, and W. Liao, "Dual-band circularly polarized stacked square microstrip antenna with small frequency ratio," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 11--12, 1599-1608, 2010.
doi:10.1163/156939310792149696
3. Ooi, T. S. and S. K. A. Rahim, "2.45 GHz and 5.8 GHz compact dual-band circularly polarized patch antenna," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 11--12, 1473-1482, 2010.
doi:10.1163/156939310792149713
4. Nasimuddin, Z. N. C. and X. M. Qing, "Dual-band circularly polarized-shaped slotted patch antenna with a small frequency-ratio," IEEE Trans. on Antennas and Propag., Vol. 58, No. 6, 2112-2115, 2010.
doi:10.1109/TAP.2010.2046851
5. Zaker, R. and A. Abdipour, "Dual-wideband circularly-polarised slot antenna using folded L-shaped stub," Electron. Lett., Vol. 47, No. 6, 361-363, 2011.
doi:10.1049/el.2011.0078
6. Bao, X. L. and M. J. Ammann, "Monofilar spiral slot antenna for dual-frequency dual-sense circular polarization," IEEE Trans. on Antennas and Propag., Vol. 59, No. 8, 3061-3065, 2011.
doi:10.1109/TAP.2011.2158964
7. Chen, C.-H. and E. K. N. Yung, "Dual-band circularly-polarized CPW-fed slot antenna with a small frequency ratio and wide bandwidths," IEEE Trans. on Antennas and Propag., Vol. 59, No. 4, 1379-1384, 2011.
doi:10.1109/TAP.2011.2109347
8. Tong, K. F. and T. P. Wong, "Circularly polarized U-slot antenna," IEEE Trans. on Antennas and Propag., Vol. 55, No. 8, 2382-2385, 2007.
doi:10.1109/TAP.2007.901930
9. Lam, K. Y., K.-M. Luk, K. F. Lee, H. Wong, and K. B. Ng, "Small circularly polarized U-Slot wideband patch antenna," IEEE Antennas Wireless Propag. Lett., Vol. 10, 87-90, 2011.
10. Nayeri, P., K.-F. Lee, A. Z. Elsherbeni, and F. Yang, "Dual-band circularly polarized antennas using stacked patches with asymmetric U-slots," IEEE Antennas Wireless Propag. Lett., Vol. 10, 492-495, 2011.
doi:10.1109/LAWP.2011.2153820