Printed, circularly polarised, microstrip line fed antenna having asymmetric slotted structure is presented. Two antennas, antenna 1 (A1) and antenna 2 (A2), having the same design but radiating with opposite senses of circular polarisation are fabricated. The geometrical structure consists of uneven combination of elements fixed through parametric variations. The measurements yielded significant impedance bandwidth (IBW) and axial ratio bandwidth (ARBW) for axial ratio (AR) ≤ 3 dB. A1 offered IBW of 9.67 GHz (2.46-12.13 GHz, 132.6%), ARBW of 7 GHz (4-11 GHz, 93.33%) and a peak realised gain of 4.05 dBi. A2 offered IBW of 10.05 GHz (2.55-12.6 GHz, 132.7%), ARBW of 7.3 GHz (3.9-11.2 GHz, 96.7%) and a peak realised gain of 4.1 dBi. This constitutes a wide coverage of over 88% of the ultra-wideband (UWB) spectrum (3.1-10.6 GHz). Omnidirectional radiation patterns and marginal group delays are the other features of these antennas. The proposed design is validated through simulations and experimental investigations.
2. Mao, S.-G., J.-C. Yeh, and S.-L. Chen, "Ultrawideband circularly colarized spiral antenna asing integrated balun with application to time-domain target detection," IEEE Trans. Antennas Propag., Vol. 57, No. 7, 1914-1920, 2009.
3. Nakano, H. and J. Yamauchi, "Printed slot and wire antennas: a review," Proceedings of the IEEE, Vol. 100, No. 7, 2158-2168, 2012.
4. Wu, J., X. Ren, Z. Li, and Y. Yin, "Modified square slot antennas for broadband circular polarization," Progress In Electromagnetics Research C, Vol. 38, 1-14, 2013.
5. Shokri, M., V. Rafii, S. Karamzadeh, Z. Amiri, and B. Virdee, "Miniaturised ultra-wideband circularly polarised antenna with modified ground plane," Electron. Lett., Vol. 50, 1786-1788, 2014.
6. Karamzadeh, S., V. Rafii, M. Kartal, and M. Dibayi, "Circularly polarized square slot antenna," ACES Journal, Vol. 30, No. 3, 327-331, 2015.
7. Karamzadeh, S., V. Rafii, M. Kartal, and H. Saygin, "Compact UWB CP square slot antenna with two corners connected by a strip line," Electron. Lett., Vol. 52, 10-12, 2016.
8. Ellis, M. S., Z. Zhao, J.Wu, X. Ding, Z. Nie, and Q. H. Liu, "A novel simple and compact microstrip fed circularly polarized wide slot antenna with wide axial ratio bandwidth for C band applications," IEEE Trans. Antennas Propag., Vol. 64, No. 4, 1552-1555, 2016.
9. Ding, K., C. Gao, T. Yu, and D. Qu, "Wideband CP slot antenna with backed FSS reflector," IET Microw. Antennas Propag., Vol. 11, No. 7, 1045-1050, 2017.
10. Mondal, T., S. Maity, R. Ghatak, and S. R. B. Chaudhuri, "Design and analysis of a wideband circularly polarised perturbed psi-shaped antenna," IET Microw. Antennas Propag., Vol. 12, No. 9, 1582-1586, 2018.
11. Nosrati, M. and N. Tavassolian, "Miniaturized circularly polarized square slot antenna with enhanced axial-ratio bandwidth using an antipodal Y-strip," IEEE Antennas and Wireless Propagation Letters, Vol. 16, 817-820, 2017.
12. Huang, H.-F. and B.Wang, "A simple V-shaped slot antenna with broadband circular polarization," Progress In Electromagnetics Research Letters, Vol. 67, 67-73, 2017.
13. Wu, Z., G. M. Wei, X. Li, and L. Yang, "A single-layer and compact circularly polarized wideband slot antenna based on bent feed," Progress In Electromagnetics Research Letters, Vol. 72, 39-44, 2018.
14. Trinh-Van, S., Y. Yang, K.-Y. Lee, and K. C. Hwang, "Broadband circularly polarized slot antenna loaded by a multiple-circular-sector," Sensors, Vol. 18, 1576-1588, 2018.
15. Xu, R., J.-Y. Li, J. Liu, S.-G. Zhou, K. Wei, and Z.-J. Xing, "A simple design of compact dualwideband square slot antenna with dual-sense circularly polarized radiation for WLAN/Wi-Fi Communications," IEEE Trans. Antennas Propag., Vol. 66, No. 9, 4884-4889, 2018.