This paper presents a quickly converging optimization technique for synthesis of filters with constant and frequency-variant couplings (FVC). Unlike the works so far appeared in the literature, the proposed technique is not based on the direct optimization of scattering parameters with assigned topology, but it consists of two procedures. Firstly, an FVC coupling matrix with assigned topology is suitably transformed by means of scaling and rotations for obtaining the new coupling matrix with constant couplings. Then, the cost function is constructed as a least squares problem involving both the eigenvalues of the new coupling matrix with constant couplings and that of the transversal coupling matrix. The solution is found via the solvopt optimization method. Two numerical examples with different topologies and specifications are synthesized to show the validation of the method presented in this paper.
2. Cameron, R. J., C. Kudsia, and R. Mansour, "Coupling matrix synthesis of filter networks," Microwave Filters for Communication Systems, 1st Edition, Hoboken, NJ, USA, 2007.
3. Kozakowski, P., A. Lamecki, P. Sypek, and M. Mrozowski, "Eigenvalue approach to synthesis of prototype filters with source/load coupling," IEEE Microw. Wireless Compon. Lett., Vol. 15, No. 2, 98-100, Feb. 2005.
doi:10.1109/LMWC.2004.842838
4. Szydlowski, L., N. Leszczynska, and M. Mrozowski, "Dimensional synthesis of coupled-resonator pseudoelliptic microwave bandpass filters with constant and dispersive couplings," IEEE Trans. Microw. Theory Techn., Vol. 62, No. 8, 1634-1646, Aug. 2014.
doi:10.1109/TMTT.2014.2332500
5. Gimenez, A. and D. Pedro, "A dual-TZ extraction technique for the synthesis of cross-coupled prototype filters," IEEE Microw. Wireless Compon. Lett., Vol. 26, No. 10, 777-779, Oct. 2016.
doi:10.1109/LMWC.2016.2601295
6. He, Y., G. Wang, and L.-G. Sun, "Direct matrix synthesis approach for narrowband mixed topology filters," IEEE Microw. Wireless Compon. Lett., Vol. 26, No. 5, 301-303, Apr. 2016.
doi:10.1109/LMWC.2016.2549098
7. Zhao, P. and K.-L. Wu, "A direct synthesis approach of bandpass filters with extracted-poles," Proc. Asia-Pacific Microw. Conf., 25-27, Seoul, South Korea, Nov. 2013.
8. Yang, Y., M. Yu, and Q.-Y. Wu, "Advanced synthesis technique for unified extracted pole filters," IEEE Trans. Microw. Theory Techn., Vol. 64, No. 12, 4463-4472, Dec. 2016.
doi:10.1109/TMTT.2016.2623618
9. He, Y., G.Wang, X.-T. Song, and L.-G. Sun, "A coupling matrix and admittance function synthesis for mixed topology filters," IEEE Trans. Microw. Theory Techn., Vol. 64, No. 12, 4444-4454, Oct. 2016.
doi:10.1109/TMTT.2016.2614666
10. Tamiazzo, S. and G. Macchiarella, "Synthesis of cross-coupled prototype filters including resonant and non-resonant nodes," IEEE Trans. Microw. Theory Techn., Vol. 63, No. 10, 3408-3415, Jul. 2015.
doi:10.1109/TMTT.2015.2457421
11. Amari, S. and U. Rosenberg, "Synthesis and design of novel in-line filters with one or two real transmission zeros," IEEE Trans. Microw. Theory Techn., Vol. 52, No. 5, 1464-1478, May 2004.
doi:10.1109/TMTT.2004.827023
12. He, Y., G. Macchiarella, G. Wang, W. Wu, L. Sun, L. Wang, and R. Zhang, "A direct matrix synthesis for in-line filters with transmission zeros generated by frequency-variant couplings," IEEE Trans. Microw. Theory Techn., Vol. 66, No. 6, 1780-1789, Apr. 2018.
doi:10.1109/TMTT.2018.2791940
13. Szydlowski, L., A. Lamecki, and M. Mrozowski, "Coupled-resonator filters with frequency-dependent couplings: Coupling matrix synthesis," IEEE Microw. Wireless Compon. Lett., Vol. 22, No. 6, 312-314, May 2012.
doi:10.1109/LMWC.2012.2197386
14. Cameron, R. J., "Advanced coupling matrix synthesis techniques for microwave filters," IEEE Trans. Microw. Theory Techn., Vol. 51, No. 1, 1-10, Jan. 2003.
doi:10.1109/TMTT.2002.806937
15. SolvOpt manual and SolvOpt Toolbox for matlab, , Available: http://www.kfunigraz.ac.at/imawww/kuntsevich/solvopt/index.html.
Submit
