Synthesis Design of Bandpass Filter for UWB Applications with Improved Selectivity
Keywords:
Bandpass filter, coupling gap, parallel coupled line, rejection band, stub, UWBAbstract
This paper presents the design of UWB threepole modified parallel coupled line bandpass filter with improved rejection in the out-of-band frequencies. To achieve the desired UWB requirements using the conventional bandpass filter design, a physical dimension optimization of space-gap between lines, line widths and lengths was applied. An equivalent circuit model is also presented and demonstrates reasonable agreement with simulation results. The optimized filter demonstrates an excellent UWB performance, covering the Federal Communication Commission spectrum bandwidth with low insertion loss and acceptable selectivity. However, this resulting filter structure presents very small gapping between adjacent resonators; that means the filter is unmanufactured. Then an example of an alternative filter structure is finally proposed with null gaping and shortcircuited stubs that yields to a fabricated prototype with selectivity improvement. Generally speaking, reasonable agreement is achieved between measurement and simulation results.
Downloads
References
Federal Communications Commission, “First report and order in the matter of revision of Part 15 of the commission’s rules regarding ultrawideband transmission systems,” Tech Report, ET-Docket 98-153, FCC02-48, Apr. 2002.
X. Li and X. Ji, “Novel compact UWB bandpass filters design with cross-coupling between λ/4 short-circuited stubs,” IEEE Microw. Wireless Compon. Lett., vol. 24, no. 1, pp. 23-25, Jan. 2014.
H. Shaman and J. S. Hong, “A novel ultrawideband (UWB) bandpass filter (BPF) with pairs of transmission zeroes,” IEEE Microw. Wireless Compon. Lett., vol. 17, no. 2, pp. 121-123, Feb. 2007.
Z.-X. Zhang and F. Xiao, “An UWB bandpass filter based on a novel type of multi-mode resonator,” IEEE Microw. Wireless Compon. Lett., vol. 22, no. 10, pp. 506-508, Oct. 2012.
P. Cai, Z. Ma, X. Guan, Y. Kobayashi, T. Anada, and G. Hagiwara, “Synthesis and realization of novel ultra-wideband bandpass filters using 3/4 wavelength parallel-coupled line resonators,” Asia-Pacific Microwave Conference, Yokohama, Japan, pp. 159-162, Dec. 2006.
A. Naghar, O. Aghzout, A. Vazquez Alejos, M. Garcıa Sanchez, and M. Essaaidi, “Design of compact wideband multi-band and ultrawideband band pass filters based on coupled half wave resonators with reduced coupling gap,” IET Microwave, Antennas and Propagation, pp. 1-7, 2015.
A. Naghar, O. Aghzout, A. Vazquez Alejos, M. Garcıa Sanchez, and M. Essaaidi, “Development of a calculator for edge and parallel coupled microstrip band pass filters,” IEEE International Symposium on Antennas and Propagation, Memphis, USA, pp. 2018-2019, Jul. 2014.
A. Naghar, O. Aghzout, A. Vazquez Alejos, M. Garcıa Sanchez, and M. Essaaidi, “Design of compact multi-band bandpass filter with suppression of second harmonic spurious by coupling gap reduction,” Journal of Electromagnetic Waves and Applications, vol. 29, no. 14, pp. 1813-1828, Aug. 2015.
S. Akhtarzad, T. R. Rowbotham, and P. B. Johns, “The design of coupled microstrip lines,” IEEE Transactions on Microwave Theory and Techniques, vol. MTT-23, no. 6, pp. 486-492, Jun. 1975.
E. Hammerstad and O. Jensen, “Accurate models for microstrip computer-aided design,” Symposium on Microwave Theory and Techniques, pp. 407- 409, Jun. 1980.
M. Kirschning and R. H. Jansen, “Accurate widerange design equations for the frequency dependent characteristic of parallel coupled microstrip lines,” IEEE Trans. Microwave Theory Tech., vol. MTT32, no. 1, pp. 83-90, Jan. 1984.
C. S. Ye, Y. K. Su, M. H. Weng, C. Y. Hung, and R. Y. Yang, “Design of the compact parallel-coupled lines wideband bandpass filters using image parameter method,” Progress In Electromagnetics Research, vol. 100, pp. 153-173, 2010.
K.-S. Chin, Y.-C. Chiou, and J.-T. Kuo, “New synthesis of parallel-coupled line bandpass filters with Chebyshev responses,” IEEE Trans. Microwave Theory Tech., vol. 56, no. 7, pp. 1516-1523, Jul. 2008.
