A dual circularly polarized (CP) antenna is proposed in this paper. By employing suspended strip line to feed the patch at the two diagonal positions with 90º phase difference, single circular polarization is firstly obtained. Then dual circular polarization is excited by an L-shaped strip. The two feeding ports near the edges of the L-shaped strip arms provide the conversion between left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). Measured results show that the proposed antenna has 10-dB return loss bandwidth of 30.5% (2.08-2.83 GHz), 10-dB isolation bandwidth of 15.7% (2.29-2.68 GHz), 3-dB axial ratio (AR) bandwidth of 25.1% (2.16-2.78 GHz).
2. Chen, Z. N., X. M. Qing, and H. L. Chung, "A universal UHF RFID reader antenna," IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 5, 1275-1282, 2009.
3. Lai, X. Z., Z. M. Xie, Q. Q. Xie, and X. L. Cen, "A dual circularly polarized RFID reader antenna with wideband isolation," IEEE Antennas Wireless Propagation Letters, Vol. 12, 1630-1633, 2013.
4. Zhao, G., L. N. Chen, and Y. C. Jiao, "Design of a broadband dual circularly polarized square slot antenna," Microwave and Optical Technology Letters, Vol. 50, No. 10, 2639-2642, 2008.
5. Narbudowicz, A., X. L. Bao, and M. J. Ammann, "Dual circularly-polarized patch antenna using even and odd feed-line modes," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 9, 4828-4831, 2013.
6. Aloni, E. and R. Kastner, "Analysis of a dual circularly polarized microstrip antenna fed by crossed slots," IEEE Transactions on Antennas and Propagation, Vol. 42, No. 8, 1053-1058, 1994.
7. Harouni, Z., L. Cirio, L. Osman, A. Gharsallah, and O. Picon, "A dual circularly polarized 2.45-GHz rectenna for wireless power transmission," IEEE Antennas Wireless Propagation Letters, Vol. 10, 306-309, 2011.
8. Haboubi, W., H. Takhedmit, J.-D. Lan Sun Luk, S.-E. Adami, B. Allard, F. Costa, C. Vollaire, O. Picon, and L. Cirio, "An efficient dual-circularly polarized rectenna for RF energy harvesting in the 2.45GHz ISM band," Progress In Electromagnetics Research, Vol. 148, 31-39, 2014.
9. Lai, X. Z., Z. M. Xie, and X. L. Cen, "Design of dual circularly polarized antenna with high isolation for RFID application," Progress In Electromagnetics Research, Vol. 139, 25-39, 2013.
10. Zhang, C. H., X. L. Liang, X. D. Bai, J. P. Geng, and R. H. Jin, "A broadband dual circularly polarized patch antenna with wide beamwidth," IEEE Antennas Wireless Propagation Letters, Vol. 13, 1457-1460, 2014.