1. Jou, C. F., J.-W. Wu, and C.-J. Wang, "Novel broadband monopole antennas with dual-band circular polarization," IEEE Trans. on Antennas and Propag., Vol. 57, 1027-1034, Apr. 2009.
doi:10.1109/TAP.2009.2015827
2. Huang, C.-Y., J.-Y. Wu, and K.-L. Wong, "Cross-slot-coupled microstrip antenna and dielectric resonator antenna for circular polarization," IEEE Trans. on Antennas and Propag., Vol. 47, 605-609, Apr. 1999.
doi:10.1109/8.768798
3. Batchelor, J. C. and R. J. Langley, "Microstrip annular ring slot antennas for mobile applications," Electronics Letters, Vol. 32, 1635-1636, Aug. 1996.
doi:10.1049/el:19961102
4. Wong, K.-L., C.-C. Huang, and W.-S. Chen, "Printed ring slot antenna for circular polarization," IEEE Trans. on Antennas and Propag., Vol. 50, 75-77, Jan. 2002.
doi:10.1109/8.992564
5. Chang, T.-N., "A CPW-fed annular slot-antenna with an L-shaped strip," Microwave Opt. Technol. Lett., Vol. 53, 2821-2827, Dec. 2011.
doi:10.1002/mop.26416
6. Hsieh, T. H. and J. S. Row, "Design of dual-frequency circularly-polarized slot antennas with switchable frequency," Microwave Opt. Technol. Lett., Vol. 52, 2023-2029, Jun. 2010.
doi:10.1002/mop.25396
7. Wang, C.-C., T.-Y. Lee, and J.-S. Row, "A simple design for circularly polarized ring-slot antennas," Microwave Opt. Technol. Lett., Vol. 53, 2262-2265, Oct. 2011.
doi:10.1002/mop.26285
8. Liu, W.-L., M.-Y. Chen, and T.-R. Chen, "A design for circularly polarized ring slot antennas backed by thin grounded substrate," Microwave Opt. Technol. Lett., Vol. 54, 1549-1775, Jul. 2012.
9. Row, J.-S., "The design of a squarer-ring slot antenna for circular polarization," IEEE Trans. on Antennas and Propag., Vol. 5, 1967-1972, Jun. 2005.
doi:10.1109/TAP.2005.848482