A novel broadband monopole antenna design with wideband circular polarization (CP) characteristic is presented. This antenna consists of a feed line and a step-shaped ground plane which is formed by cutting a notch in the upper left corner of an asymmetric ground plane. The asymmetric ground plane is capable of exciting two orthogonal electric field vectors with equal amplitude and 90° phase difference (PD) for CP. By cutting a notch, the impedance-bandwidth can be enhanced greatly and the 3-dB axial ratio (AR) bandwidth is improved meanwhile. The measured impedance-bandwidth is about 5.96 GHz (84.7%) from 4.06 to 10.02 GHz, and the measured AR-bandwidth is about 2.64 GHz (36.5%) from 5.91 to 8.55 GHz. The results show that the antenna can achieve wide impedance-bandwidth and wide AR-bandwidth simultaneously.
2. Wang, C.-J. and C.-H. Lin, "A circularly polarized quasi-loop antenna," Progress In Electromagnetics Research, Vol. 84, 333-348, 2008.
3. Kasabegoudar, V. G. and K. J. Vinoy, "A broadband suspended microstrip antenna for circular polarization," Progress In Electromagnetics Research, Vol. 90, 353-368, 2009.
4. Lai, C.-H., T.-Y. Han, and T.-R. Chen, "Circularly-polarized reconfigurable microstrip antenna," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 2-3, 195-201, 2009.
5. Nasimuddin, X. Qing, and Z.-N. Chen, "Compact asymmetric-slit microstrip antennas for circular polarization," IEEE Trans. Antennas Propag., Vol. 59, No. 1, 285-288, 2011.
6. Nasimuddin, Z.-N. Chen, and X. Qing, "Asymmetric-circular shaped slotted microstrip antennas for circular polarization and RFID applications," IEEE Trans. Antennas Propag., Vol. 58, No. 12, 3821-3828, 2010.
7. Cao, W., B. Zhang, T. Yu, and H. Li, "A single-feed broadband circular polarized rectangular microstrip antenna with chip-resistor loading," IEEE Antennas Wireless Propag. Lett., Vol. 9, 1065-1068, 2010.
8. Tong, K.-F. and J. Huang, "New proximity coupled feeding method for reconfigurable circularly polarized microstrip ring antennas," IEEE Trans. Antennas Propag., Vol. 56, No. 7, 1860-1866, 2008.
9. Ahdi Rezaeieh, S. and M. Kartal, "A new triple band circularly polarized square slot antenna design with crooked T and F-shape strips for wireless applications," Progress In Electromagnetics Research, Vol. 121, 1-18, 2011.
10. Sze, J.-Y. and S.-P. Pan, "Design of broadband circularly polarized square slot antenna with a compact size," Progress In Electromagnetics Research, Vol. 120, 513-533, 2011.
11. Mousavi, P., B. Miners, and O. Basir, "Wideband L-shaped circular polarized monopole slot antenna," IEEE Antennas Wireless Propag. Lett., Vol. 9, 822-825, 2010.
12. Tseng, L. Y. and T. Y. Han, "Microstrip-fed circular slot antenna for circular polarization," Microwave Opt. Technol. Lett., Vol. 50, 1056-1058, 2008.