An ultra-wideband (UWB) bandpass filter (BPF) with hybrid coplanar waveguide (CPW)/microstrip structure is introduced in this paper. Then a pair of lowpass filters is integrated on the CPW feed lines to achieve a good out-of-band rejection. At last, a notched band with two transmission zeros is realized at 5.8 GHz by using a symmetric E-shaped slot-line and etching slots on microstrip resonator. Two transmission zeros are realized in the desired notched band, and out-of band rejection is more than 32 dB. In order to prove the validity, the proposed filter is fabricated and measured, and the measured results are in good agreement with simulated ones.
2. Tian, X.-K. and Q.-X. Chu, "A compact UWB bandpass filter with improved out-of-band A compact UWB bandpass filter with improved out-of-band," Progress In Electromagnetics Research Letters, Vol. 22, 191-197, 2011.
3. Wang, H., L. Zhu, W. Menzal, and Z. N. Chen, "Ultra-wideband (UWB) bandpass filters using hybrid mivrostrip/CPW structures," Microwave Conference, 1216-1219, 2006.
doi:10.2528/PIERL14020801
4. Cui, C., Z. Hou, H. Wang, and W. Wu, "Novel band-notched UWB bandpass filter using microstrip/slotline ring resonators," Progress In Electromagnetics Research Letters, Vol. 45, 69-73, 2014.
doi:10.1002/mop.27663
5. Wang, K., S. W. Wong, and Q.-X. Chu, "A compact UWB CPW bandpass filter with short-ended H-shaped resonator and controllable notched band," Microwave Opt. Technol. Lett., Vol. 55, 1577-1581, 2013.
6. Li, K., D. Kurita, and T. Matsui, "An ultra-wideband bandpass filter using broadside-coupled microstrip-coplanar waveguide structure," IEEE International Conference on Ultra-Wideband, 446-451, 2005.
doi:10.1002/mop.23818
7. Wong, S. W. and L. Zhu, "Ultra-wide bandpass filters with sharpened roll-off skirts, extended upper-stopband, and controllable notch-band," Microwave Opt. Technol. Lett., Vol. 50, 2958-2961, 2008.
8. Yao, B. Y., Y. G. Zhou, and Q. S. Cao, "UWB bandpass filter with multi-notched bands using microstrip/coplanar waveguide," 8th International Symposium on Antenna, Propagation and EM Theory, 637-640, 2008.
9. Shaman, H. and J.-S. Hong, "Ultra-wideband (UWB) microstripbandpass filter with narrow notched band," 38th European Microwave Conference, 857-860, 2008.
doi:10.2528/PIERL14011504
10. Peng, H., Y. Luo, and J. Zhao, "Compact microstrip UWB bandpass filter with two band-notches for UWB applications," Progress In Electromagnetics Research Letters, Vol. 45, 25-30, 2014.
11. Gao, J., L. Zhu, M. Menzel, and F. Bogelsack, "Short-circuited CPW multiple-mode resonator for ultra-wideband (UWB) bandpass filter," IEEE Microw. Wireless Compon. Lett., Vol. 16, No. 3, 124-126, 2006.
doi:10.1049/el:20053466
12. Wang, H. and L. Zhu, "Ultra-wideband bandpass ¯lter using back-to-back microstrip-to-CPW transition structure," Electron. Lett., Vol. 41, No. 24, 1337-1338, 2005.