A tunable impedance matching network is applied to achieve very widely tunable antennas, whose geometries are independent and unchanged to simplify the design. The attached matching network as the antenna feeding network enables any unspecified UWB antenna to tune the operation frequency continuously with high selectivity by merely one single control. This is quite different from filter-based concept which is complicated to co-design and implement a tiny narrow band tunable filter over wide frequency ranges and very difficult to control with one element. And also the design, adjustment, and optimization of the matching network are much simpler, quicker, and lower cost than geometry-modified antenna design. The analysis of precise high frequency circuit models is used predict the performance in simulation. Fabricated prototype antennas are measured by using horn antennas to validate the antenna performance. The tunable frequency ranges from 1.8 GHz to 2.8 GHz (155%) and 2.19 GHz to 3.86 GHz (176%). Moreover, compared to other matching network-based solutions, non-ideal effects in undesired bands other than the operation frequency band are suppressed, so the performance is improved. One wide-tuning antenna using one single element to control can be carried out by tunable matching networks without complicated designs.
2. Melde, K. L., H.-J. Park, H.-H. Yeh, B. Fankem, Z. Zhou, and W. R. Eisenstadt, "Software defined match control circuit integrated with a planar inverted-F antenna," IEEE Trans. on Antennas and Propagation, Vol. 58, 3884-3890, 2010.
3. Sheta, A.-F. and S. F. Mahmoud, "A widely tunable compact patch antenna," IEEE Antennas Wireless Propagat. Lett., Vol. 7, 40-42, 2008.
4. Hai, J., M. Patterson, C. Zhang, and G. Subramanyam, "Frequency tunable microstrip patch antenna using ferroelectric thin film varactor," Aerospace & Electronics Conference (NAECON), Proceedings of the IEEE 2009 National, 248-250, 2009.
5. Yang, S.-L. S., A. A. Kishk, and K.-F. Lee, "Frequency reconfigurable U-slot microstrip patch antenna," IEEE Antennas Wireless Propagat. Lett., Vol. 7, 127-129, 2008.
6. Nikolaou, S., R. Bairavasubramanian, C. Lugo, Jr., I. Carrasquillo, D. C. Thompson, G. E. Ponchak, J. Papapolymerou, and M. M. Tentzeris, "Pattern and frequency reconfigurable annular slot antenna using PIN diodes," IEEE Trans. on Antennas and Propagation, Vol. 54, No. 2, 439-448, Feb. 2006.
7. Yang, C.-L., "Novel high selective band-tunable antennas over ultra-wide ranges using reconfigurable matching network," IEEE Antennas and Propagation Society International Symposium, 1-4, Jun. 2009.
8. Nieuwoudt, A., J. Kawa, and Y. Massoud, "Automated design of tunable impedance matching networks for reconfigurable wireless applications," 45th ACM/IEEE Design Automation Conference, 498-503, 2008.
9. Hoarau, C., N. Corrao, J.-D. Arnould, P. Ferrari, and P. Xavier, "Complete design and measurement methodology for a tunable RF impedance-matching network," IEEE Trans. on Microwave Theory and Techniques, Vol. 56, No. 11, 2620-2627, Nov. 2008.
10. Schmidt, M., E. Lourandakis, A. Leidl, S. Seitz, and R.Weigel, "A comparison of tunable ferroelectric PI and T-matching networks," Proceedings of the 37th European Microwave Conference, 98-101, 2007.
11. Thompson, M. and J. K. Fidler, "Determination of the impedance matching domain of passive LC ladder networks: Theory and implementation," J. Franklin Institute, Vol. 333(B), No. 2, 141-155, 1996.
12. Sun, Y. and J. K. Fidler, "Design method for impedance matching networks," IEE Proceedings Circuits, Devices and Systems, Vol. 143, 186-194, 1996.
13. Stauffer, G. H., "Finding the lumped element varactor diode model," High Frequency Electronics, Summit Technical Media, 2003.
14. Yuliang, Z., H. Maune, A. Giere, M. Sazegar, and R. Jakoby, "Constraints on effcient control of tunable impedance matching network based on barium-strontium-titanate thick-film varactors," 38th European Microwave Conference, 805-808, 2008.