In this paper, a novel wideband single-feed circularly polarized patch antenna is presented. The antenna consists of an L-shaped probe, four parasitic patches perpendicular to the probe, and a planar reflector. By modifying the structure of the patches, two orthogonal radiation modes are created to realize the circular polarization in the broadside direction. This antenna exhibits a wide impedance bandwidth of 82.4% from 2 GHz to 4.8 GHz for the voltage standing wave ratio (VSWR) ≤ 2 and a 3-dB axial ratio (AR) bandwidth of 56.2% from 2.11 GHz to 3.77 GHz, over which the antenna gains vary from 5.7 dBic to 9.7 dBic. The measured results agree well with the simulated ones.
2. Hu, Y.-J., W.-P. Ding, W.-M. Ni, and W.-Q. Cao, "Broadband circularly polarized cavity-backed slot antenna array with four linearly polarized disks located in a single circular slot," IEEE Antennas Wireless Propog. Lett., Vol. 11, 496-499, 2012.
3. Guo, Y.-X. and D. C. H. Tan, "Wideband single-feed circularly polarized patch antenna with conical radiation pattern," IEEE Antennas Wireless Propog. Lett., Vol. 8, 924-926, 2009.
4. Wang, Z., S. Fang, S. Fu, and S. Jia, "Single-fed broadband circularly polarized stacked patch antenna with horizontally meandered strip for universal UHF RFID applications," Microw. Opt. Technol. Lett., Vol. 59, 1066-1073, 2011.
5. Chung, K. L., "A wideband circularly polarized H-shaped patch antenna," A wideband circularly polarized H-shaped patch antenna Propag., Vol. 58, 3379-3383, 2010.
6. He, Y., W. He, and H. Wong, "A wideband circularly polarized cross-dipole antenna," IEEE Antennas Wireless Propog. Lett., Vol. 13, 67-70, 2014.
7. Li, M. and K.-M. Luk, "A wideband circularly polarized antenna for microwave and millimeter-wave applications," IEEE Trans. Antennas Propag., Vol. 62, 1872-1879, 2014.