A novel compact wideband b andpass filter using rotational symmetric loaded structure is proposed in this paper. A λ/4 parallel coupled line is first introduced to form a passband with desired center frequency. The rotational symmetric structure with short/open circuit stubs is then introduced as a loading structure to improve the filter's performance. The rotational symmetric loading structure is discussed in detail in this paper, and a pair of transmission zeros is obtained and located at two sides of the passband to improve the passband selectivity intensively. Moreover, three open circuit stubs are utilized to replace one single stub for obtaining a wide stopband. At last, the proposed filter is fabricated and measured, and the results show a good agreement with each other.
2. Wu, G.-L., W. Mu, X.-W. Dai, and Y.-C. Jiao, "Design of novel dual-band bandpass filter with microstrip meander-loop resonator and CSRRDGS," Progress In Electromagnetics Research, Vol. 78, 17-24, 2008.
doi:10.2528/PIER07090301
3. Deng, K., J.-Z. Chen, S.-J. Sun, B. Wu, and C.-H. Liang, "Microstrip wideband bandpass filter based on square ring loaded resonator," Progress In Electromagnetics Research, Vol. 43, 175-184, 2013.
doi:10.2528/PIERL13100805
4. Chen, D., L. Zhu, and C. Cheng, "A novel wideband bandpass filter using stub-loaded ring resonator and tapped feed," Progress In Electromagnetics Research Letters, Vol. 42, 37-44, 2013.
doi:10.2528/PIERL13070601
5. Chen, Y.-M., S.-F. Chang, C.-C. Chang, and T.-J. Hung, "Design of stepped-impedance combline bandpass filters with symmetric insertion-loss response and wide stopband range," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 10, Oct. 2007.
6. Weng, M.-H., C.-Y. Hung, and Y.-K. Su, "A Hairpin line diplexer for direct sequence ultra-wideband wireless communications," IEEE Microwave and Wireless Components Letters, Vol. 17, No. 7, Jul. 2007.
7. Tsujiguchi, T., H. Matsumoto, and T. Nishikawa, "A miniaturized end-coupled bandpass filter using hair-pin coplanar resonators," IEEE MTT-S Int. Microw. Symp. Dig., Vol. 2, 829-832, 1998.
8. Wong, S. W. and L. Zhu, "EBG-embedded multiple-mode resonator for UWB bandpass filter with improved upper-stopband performance," IEEE Microwave and Wireless Components Letters, Vol. 17, No. 6, Jul. 2007.
9. Shaman, H. and J.-S. Hong, "Input and output cross-coupled wideband bandpass filter," IEEE Transactions on Microwave Theory and Techniques, Vol. 55, No. 12, Dec. 2007.
doi:10.1109/TMTT.2007.910066
10. Wong, S. W., Z. N. Chen, and Q.-X. Chu, "Rotationally symmetric microstrip-line millimetre-wave bandpass filter with two transmission zeros," IET Electronic Letter, Vol. 47, No. 22, 1232-1233, Oct. 2011.
doi:10.1049/el.2011.2571
11. Wong, S. W., Z. N. Chen, and Q. X. Chu, "Microstrip-line millimeter-wave bandpass filter using interdigital coupled-line," IET Electronic Letter, Vol. 48, No. 4, 224-225, Feb. 2012.
doi:10.1049/el.2011.4003
12. Wong, S. W., K. Wang, Z. N. Chen, and Q. X. Chu, "Rotationally symmetric coupled-lines bandpass filter with two transmission zeros," Progress In Electromagnetics Research, Vol. 135, 641-656, Jan. 2013.
doi:10.2528/PIER12112405
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