A frequency reconfigurable antenna with dual-band operation is presented. The antenna has a circular radiating patch loaded with an annular slot, and the slotted patch is shorted to the ground plane with four conducting posts. The antenna has three feed ports. Two of the ports are used to excite the slot mode resonant at a lower frequency, and broadside radiation with dual orthogonal linear polarizations can be obtained. The other port is used to excite the monopolar-patch mode resonant at a higher frequency, and conical radiation with vertical polarization can be yielded. To reconfigure the operation frequencies, four varactors are symmetrically placed across the annular slot. The simulated results indicate that the resonant frequency of the slot mode can be tuned from 1.62 to 1.17 GHz when the capacitance of the varactors is varied from 0.6 to 1.8 pF; besides, for each capacitance value, the impedance bandwidth of the antenna operating in the monopolar-patch mode can cover the frequencies from 2.4 to 2.5 GHz. Experiments are also carried out to validate the simulated data.
2. Nguyen-Trong, N., A. Piotrowski, and C. Fumeaux, "A frequency-reconfigurable dual-band low-profile monopolar antenna," IEEE Trans. Antennas Propag., Vol. 65, 3336-3343, 2017.
3. Nguyen-Trong, N., L. Hall, and C. Fumeaux, "A frequency- and pattern-reconfigurable center-shorted microstrip antenna," IEEE Antennas Wireless Propag., Vol. 15, 1955-1958, 2016.
4. Zhang, J., S. Yan, G. A. E. Vandenbosch, and , "Radial CRLH-TL-based dual-band antenna with frequency agility," IEEE Trans. Antennas Propag., Vol. 68, 5664-5669, 2020.
5. Al-Zayed, A. S., M. A. Kourah, and S. F. Mahmoud, "Frequency-reconfigurable single- and dual-band designs of a multi-mode microstrip antenna," IET Microw. Antennas Propag., Vol. 8, 1105-1112, 2014.
6. Li, T., H. Zhai, X. Wang, L. Li, and C. Liang, "Frequency-reconfigurable bow-tie antenna for Bluetooth, WiMAX, and WLAN applications," IEEE Antennas Wireless Propag. Lett., Vol. 14, 171-174, 2016.
7. Mayuri, P., N. D. Rani, N. B. Subrahmanyam, and B. T. Madhav, "Design and analysis of a compact reconfigurable dual band notched UWB antenna," Progress In Electromagnetics Research C, Vol. 98, 141-153, 2020.
8. Ge, L., Y. Li, J. Wang, and C. Y. D. Sim, "A low-profile reconfigurable cavity-backed slot antenna with frequency, polarization, and radiation pattern agility," IEEE Trans. Antennas Propag., Vol. 65, 2182-2189, 2017.
9. Sharma, S. and C. C. Tripathi, "Frequency reconfigurable U-slot antenna for SDR application," Progress In Electromagnetics Research Letters, Vol. 55, 129-136, 2015.
10. Li, P. K., Z. H. Shao, Q. Wang, and Y. J. Cheng, "Frequency- and pattern reconfigurable antenna for multistandard wireless applications," IEEE Antennas Wireless Propag. Lett., Vol. 14, 333-336, 2015.
11. Anu, A., P. Abdulla, P. M. Jasmine, and T. Rekha, "A varactor-tuned aperture coupled dual band cylindrical dielectric resonator antenna for C-band application," Progress In Electromagnetics Research C, Vol. 94, 261-272, 2019.
12. Row, J. S. and L. K. Kuo, "A pattern diversity antenna with six input ports," Microwave and Opt. Technol. Lett., Vol. 62, 1252-1258, 2020.
13. Sun, C., H. Zheng, L. Zhang, and Y. Liu, "A compact frequency-reconfigurable patch antenna for Beidou (COMPASS) navigation system," IEEE Antennas Wireless Propag. Lett., Vol. 13, 967-970, 2014.
14. Ferrero, F., C. Luxey, R. Staraj, G. Jacquemod, M. Yedlin, and V. Fusco, "Theory and design of a tunable quasi-lumped quadrature coupler," Microwave and Opt. Technol. Lett., Vol. 51, 2219-2222, 2009.
15. Row, J. S. and C. J. Shih, "Polarization-diversity ring slot antenna with frequency agility," IEEE Trans. Antennas Propag., Vol. 60, 3953-3957, 2012.