1. Wired vs. Wireless Technologies for Communication Networks in Utility Markets, https://www.utilityproducts.com/test-measurement/article/16002788/wired-vs-wireless-technologies-for-communication-networks-in-utility-markets, January 7, 2022.

2. Vodafone and Samsung strategic partnership to launch Smart Home services, https://www.vodafone.com/news-and-media/vodafone-group-releases/news/vodafone-and-samsung-strategic-partership, January 7, 2022.

3. Global update on spectrum for 4G and 5G, https://www.qualcomm.com/media/documents/files/spectrum-for-4g-and-5g.pdf, December 2020.

4. Dudzinsky, Jr., S. J. Atmospheric effect on terrestrial millimeter-wave communication, https://www.rand.org., March 1974.
doi:10.1109/EUMA.1974.332040

5. Kusaladharma, S. and C. Tellambura, "An overview of cognitive radio networks," Wiley Encycl. Electr. Electron. Eng., August 2017.

6. Kingsly, S., D. Thangarasu, M. Kanagasabai, M. Gulam Nabi Alsath, R. R. Thipparaju, S. K. Palaniswamy, and P. Sambandam, "Multiband reconfigurable filtering monopole antenna for cognitive radio applications," IEEE Antennas Wirel. Propag. Lett., Vol. 17, No. 8, 1416-1420, 2018.
doi:10.1109/LAWP.2018.2848702

7. Tang, M. C., Z. Wen, H. Wang, M. Li, and R. W. Ziolkowski, "Compact, Frequency-reconfigurable filtenna with sharply defined wideband and continuously tunable narrowband states," IEEE Trans. Antennas Propag., Vol. 65, No. 10, 5026-5034, 2017.
doi:10.1109/TAP.2017.2736535

8. Mishra, S. R. and S. Kochuthundil Lalitha, "Filtennas for wireless application: A review," Int. J. RF Microw. Comput. Aided Eng., Vol. 29, No. 10, 1-28, 2019.

9. Nella, A. and A. S. Gandhi, "A five-port integrated UWB and narrowband antennas system design for CR applications," IEEE Trans. Antennas Propag., Vol. 66, No. 4, 1669-1676, 2018.
doi:10.1109/TAP.2018.2800718

10. Nachouane, H., A. Najid, A. Tribak, and F. Riouch, "Dual port antenna combining sensing and communication tasks for cognitive radio," International Journal of Electronics and Telecommunications, Vol. 62, No. 2, 121-127, 2016.
doi:10.1515/eletel-2016-0016

11. Srikar, D. and S. Anuradha, "A compact 3 port integrated wide band sensing antenna and narrow band antennas for cognitive radio applications," 2019 PhotonIcs & Electromagnetics Research Symposium --- Spring (PIERS --- Spring), Rome, Italy, June 17-20, 2019.

12. Ramadan, A. H., J. Costantine, M. Al-Husseini, K. Y. Kabalan, Y. Tawk, and C. G. Christodoulou, "Tunable filter-antennas for cognitive radio applications," Progress In Electromagnetics Research B, Vol. 57, 253-265, 2014.
doi:10.2528/PIERB13112005

13. Atallah, H. A., A. B. Abdel-Rahman, K. Yoshitomi, and R. K. Pokharel, "Compact frequency reconfigurable filtennas using varactor loaded T-shaped and H-shaped resonators for cognitive radio applications," IET Microwaves, Antennas Propag., Vol. 10, No. 9, 991-1001, 2016.
doi:10.1049/iet-map.2015.0700

14. Lee, W. W. and B. Jang, "A tunable MIMO antenna with dual-port structure for mobile phones," IEEE Access, Vol. 7, 34113-34120, 2019.
doi:10.1109/ACCESS.2019.2904051

15. Hannula, J. M., T. O. Saarinen, A. Lehtovuori, J. Holopainen, and V. Viikari, "Tunable eight-element MIMO antenna based on the antenna cluster concept," IET Microwaves, Antennas Propag., Vol. 13, No. 7, 959-965, 2019.
doi:10.1049/iet-map.2018.5742

16. Ikeda, T., S. Saito, and Y. Kimura, "A frequency-tunable varactor-loaded single-layer ring microstrip antennas fed by an L-probe with a reduced bias circuit," 2017 International Symposium on Antennas and Propagation (ISAP), Thailand, October 30-November 2, 2017.

17. Fischer, B. E., I. J. Lahaie, M. D. Huang, M. H. A. J. Herben, A. C. F. Reniers, and P. F. M. Smulders, "Measurements corner: Causes of discrepancies between measurements and EM simulations of millimeter-wave antennas," IEEE Antennas Propag. Mag., Vol. 55, No. 6, 139-149, 2013.
doi:10.1109/MAP.2013.6781719

18. Chen, C. J., "Design of parallel-coupled dual-mode resonator bandpass filters," IEEE Trans. Components, Packag. Manuf. Technol., Vol. 6, No. 10, 1542-1548, 2016.
doi:10.1109/TCPMT.2016.2601647

19. Liu, Q., D. F. Zhou, D. W. Zhang, D. L. Lu, and Y. Zhang, "Dual-mode microstrip patch bandpass filters with generalized frequency responses," IEEE Access, Vol. 7, 163537-163546, 2019.
doi:10.1109/ACCESS.2019.2952403

20. Shome, P. P. and T. Khan, "A quintuple mode resonator based bandpass filter for ultra-wideband applications," Microsyst. Technol., Vol. 26, 2295-2304, 2020.
doi:10.1007/s00542-019-04697-5

21. Lin, S. C., P. H. Deng, Y. S. Lin, C. H. Wang, and C. H. Chen, "Wide-stopband microstrip bandpass filters using dissimilar quarter-wavelength stepped-impedance resonators," IEEE Trans. Microw. Theory Tech., Vol. 54, No. 3, 1011-1018, 2006.
doi:10.1109/TMTT.2005.864139

22. Sekiya, N. and S. Sugiyama, "HTS dual-band bandpass filters using stub-loaded hair-pin resonators for mobile communication systems," Phys. C Supercond. and Its Appl., Vol. 504, 88-92, 2014.
doi:10.1016/j.physc.2014.03.021

23. Pozar, D. M., Microwave Engineering, John Wiley & Sons, 2011.

24. Balanis, C. A., Advanced Engineering Electromagnetic, John Wiley & Sons, 1999.

25. Zhang, Z., F. Zhao, and A. Wu, "A tunable open ring coupling structure and its application in fully tunable bandpass filter," Int. J. Microw. Wirel. Technol., Vol. 11, No. 8, 782-786, 2019.
doi:10.1017/S1759078719000485

26. Varactor Diode BB659, Data Sheet, Semiconductor and System Solutions-Infineon Technologies, https://www.infineon.com/, January 6, 2022.

27. Wen, L. H., S. Gao, Q. Luo, Q. Yang, W. Hu, and Y. Yin, "A low-cost differentially driven dual-polarized patch antenna by using open-loop resonators," IEEE Trans. Antennas Propag., Vol. 67, No. 4, 2745-2750, 2019.
doi:10.1109/TAP.2019.2896491