A coplanar waveguide-fed circularly polarized square slot antenna with the feasibility of obtaining a wider bandwidth and a relatively smaller size is proposed and demonstrated. The proposed antenna, consisting of a stepped feeding strip, a modified grounded L-shaped radiating patch, an inverted-L grounded strip and an asymmetric ground with an L-shaped slot as well as two horizontal slots, is designed, analyzed and fabricated. Good agreement between simulated and measured results is observed. Simulation and measurement results reveal that the proposed antenna can provide an impedance bandwidth of 106.3% (2.3-7.52 GHz) and a 3-dB axial ratio (AR) bandwidth of 90.2% (2.25-5.95 GHz). Additionally, within the effective circular polarization (CP) bandwidth of 88.5% (2.3-5.95 GHz), the proposed antenna has gains from 1.9 dBic to 5.2 dBic with an average gain of 3.9 dBic.
2. Rezaeieh, S.-A., A. Abbosh, and M.-A. Antoniades, "Compact CPW-fed planar monopole antenna with wide circular polarization bandwidth," IEEE Antennas Wireless Propag. Lett., Vol. 12, 1295-1298, 2013.
3. Jan, J.-Y., C.-Y. Pan, K.-Y. Chiu, and H.-M. Chen, "Broadband CPW-fed circularly-polarized slot antenna with an open slot," IEEE Trans. Antennas Propag., Vol. 61, No. 3, 1418-1422, Mar. 2013.
4. Pourahmadazar, J., C. Ghobadi, J. Nourinia, N. Felegari, and H. Shirzad, "Broadband CPWfed circularly polarized square slot antenna with inverted-L strips for UWB applications," IEEE Antennas Wireless Propag. Lett., Vol. 10, 369-372, 2011.
5. Zhang, L., Y.-C. Jiao, Y. Ding, B. Chen, and Z.-B.Weng, "CPW-fed broadband circularly polarized planar monopole antenna with improved ground-plane structure," IEEE Trans. Antennas Propag., Vol. 61, No. 9, 4824-4828, Sep. 2013.
6. Li, G.-H., H.-Q. Zhai, L. Li, and C.-H. Liang, "A nesting-L slot antenna with enhanced circularly polarized bandwidth and radiation," IEEE Antennas Wireless Propag. Lett., Vol. 13, 225-228, Feb. 2014.
7. Zhang, H., Y.-C. Jiao, T. Ni, and W.-L. Liang, "Broadband circularly polarised antenna with asymmetric ground and L-shaped strips," Electron. Lett., Vol. 50, No. 23, 1660-1662, Nov. 2014.
8. Rezaeieh, S.-A., S. Simsek, and J. Pourahmadazar, "Design of a compact broadband circularlypolarized slot antenna for wireless applications," Microwave Opt. Technol. Lett., Vol. 55, No. 2, 413-418, Feb. 2013.
9. Liu, Y.-W. and P. Hsu, "Broadband circularly polarised square slot antenna fed by coplanar waveguide," Electron. Lett., Vol. 49, No. 16, 976-977, Aug. 2013.
10. Felegari, N., J. Nourinia, C. Ghobadi, and J. Pourahmadazar, "Broadband CPW-fed circularly polarized square slot antenna with three inverted-L-shape grounded strips," IEEE Antennas Propag. Lett., Vol. 10, 274-277, Apr. 2011.
11. Valagiannopoulos, C.-A., "On smoothening the singular field developed in the vicinity of metallic edges," International Journal of Applied Electromagnetics and Mechanics, Vol. 31, 67-77, 2009.
12. Valagiannopoulos, C.-A., "Electromagnetic propagation into parallel-plate waveguide in the presence of a skew metallic surface," Electromagnetics, Vol. 31, No. 8, 593-605, Oct. 2011.
13. Unal, G.-S. and M.-I. Aksun, "Bridging the gap between RF and optical patch antenna analysis via the cavity model," Scientific Reports, Nov. 2015.
14. Valagiannopoulos, C. A., "High selectivity and controllability of a parallel-plate component with a filled rectangular ridge," Progress In Electromagnetics Research, Vol. 119, 497-511, 2011.
15. Valagiannopoulos, C. A., "On examining the influence of a thin dielectric strip posed across the diameter of a penetrable radiating cylinder," Progress In Electromagnetics Research C, Vol. 3, 203-214, 2008.
16. Valagiannopoulos, C.-A., "Semi-analytic solution to a cylindrical microstrip with inhomogeneous substrate," Electromagnetics, Vol. 27, No. 8, 527-544, Nov. 2007.
17. Han, R.-C. and S.-S. Zhong, "Broadband circularly-polarised chifre-shaped monopole antenna with asymmetric feed," Electron. Lett., Vol. 52, No. 4, 256-258, Feb. 2016.
18. Podilchak, S.-K., J.-C. Johnstone, M. Clenet, and Y. M. M. Antar, "A compact wideband dielectric resonator antenna with a meandered slot ring and cavity backing," IEEE Antennas Wireless Propag. Lett., Vol. 15, 909-913, 2016.