1. Heidari, A. A., M. Heyrani, and M. Nakhkash, "A dual-band circularly polarized stub loaded microstrip patch antenna for GPS applications," Progress In Electromagnetics Research, Vol. 92, 195-208, 2009.
doi:10.2528/PIER09032401
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