1. Balanis, C. A., Antenna Theory Analysis and Design, 2nd Ed., John Wiley and Sons Inc., 1997.
2. Wood, C., "Improved bandwidth of microstrip antennas using parasitic elements," IEE Proceedings H: Microwaves, Optics and Antennas, Vol. 127, No. 4, 231-234, 1980.
doi:10.1049/ip-h-1.1980.0049
3. Ketineni, R. V., U. Balaji, and A. Das, "Improvement of bandwidth in microstrip antennas using parasitic patch," IEEE Antennas and Propagation Symposium, 1943-1947, 1992.
4. Dahele, J. S., K. F. Lee, and D. P.Wong, "Dual-frequency stacked annular-ring microstrip antenna," IEEE Transactions on Antennas and Propagation, Vol. 35, No. 11, 1281-1285, November 1987.
doi:10.1109/TAP.1987.1143997
5. Gomez-Tagle, J. and C. G. Christodoulou, "Extended cavity model analysis of stacked microstrip ring antennas," IEEE Transactions on Antennas and Propagation, Vol. 45, No. 11, 1626-1635, November 1997.
doi:10.1109/8.650074
6. Nurie, N. S. and R. J. Langley, "Input impedance of concentric ring microstrip antennas for dual frequency band operation including surface wave coupling," IEE Proceedings H --- Microwaves, Antennas and Propagation, Vol. 137, No. 6, 331-336, November 1990.
doi:10.1049/ip-h-2.1990.0061
7. Chen, X., G. Fu, S. X. Gong, Y. L. Yan, and W. Zhao, "Circularly polarized stacked annular-ring microstrip antenna with integrated feeding network for UHF RFID readers," IEEE Antennas and Wireless Propagation Letters, Vol. 9, 542-545, 2010.
doi:10.1109/LAWP.2010.2051791
8. Zhang, X. and L. Zhu, "Patch antennas with loading of a pair of shorting pins toward flexible impedance matching and low cross polarization," IEEE Transactions on Antennas and Propagation, Vol. 64, No. 4, 1226-1233, April 2016.
doi:10.1109/TAP.2016.2526079
9. Balaji, U., "Circular patch antenna for radio LAN applications," International Conference on Antennas and Propagation, 723-726, 2003.
10. Goto, J., S. Yamaguchi, K. Kihira, T. Toru, and H. Miyashita, "Dual frequency patch antenna using partially shorted annular ring patch antenna," IEEE Antennas and Propagation Symposium URSI, 1869-1870, 2014.
11. Richards, W. F., J. D. Ou, and S. A. Long, "A theoretical and experimental investigation of annular, annular sector and circular sector microstrip antennas," IEEE Transactions on Antennas and Propagation, Vol. 32, No. 8, 864-867, August 1984.
doi:10.1109/TAP.1984.1143432
12. Liu, X., Y. Li, Z. Liang, S. Zheng, J. Liu, and Y. Long, "A method of designing a dual-band sector ring microstrip antenna and its application," IEEE Transactions on Antennas and Propagation, Vol. 64, No. 11, 4896-4900, November 2016.
doi:10.1109/TAP.2016.2596903
13. Deshmukh, A. A. and N. V. Phatak, "Broadband sectoral microstrip antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 727-730, 2015.
doi:10.1109/LAWP.2014.2385108
14. Zhang, J., Y. Li, Z. Liang, S. Zheng, and Y. Long, "Design of a multifrequency one-quarter-rings microstrip antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 209-212, 2015.
doi:10.1109/LAWP.2014.2360412
15. Tanaka, T., M. Takahashi, and K. Ito, "Study on the radiation characteristics of a miniaturized circularly polarized circular sector patch antenna," IEEE Antennas and Propagation Symposium, 1560-1564, 2006.
16. Kandwal, A. and S. K. Khah, "A novel design of gap-coupled sectoral patch antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 12, 674-677, 2013.
doi:10.1109/LAWP.2013.2264103
17. Dalli, A., L. Zenkouar, and S. Bri, "Conception of circular sector microstrip antenna and array," International Journal of Microwave Applications, 32-37, November-December 2012.