This paper presents a novel compact "via-less" UWB filter derived from a quarter-wavelength short-circuited stubs model. In this compact "via-less" UWB filter, there is no connecting vias as short circuit elements. Unlike its previous model that has 5 short-circuited stubs, this novel shape consists of two pairs of stubs which are joint together to share on the same microstrip patch and thus reduces total size of the UWB filter itself making it more compact in nature. With proper width optimization, the microstrip patch is able to decouple and provides low impedance to the ground in the UWB frequencies range. The filter delivers 3.85 GHz to 10.44 GHz frequency range with 92.23% of fractional bandwidth. The magnitude of insertion loss is below than 0.53 dB and the return loss is lower than -14.8 dB in the passband frequencies. The -3 dB bandwidth is from 3.85 GHz to 10.44 GHz with 92.23% of fractional bandwidth. The group delay only varied by 0.47 ns in the passband, which makes it suitable for radio communication systems.
1. FCC, "Revision of part 15 of the commission's rules regarding ultra-wide-band transmission system ," Tech. Rep., ET-Docket, 98-153, 2002.
2. Kuo, T. N., S. C. Lin, and C. H. Chen, "Compact ultrawideband bandpass filters using composite microstrip-coplanarwaveguide structure," IEEE Transactions on Microwave Theory and Techniques, Vol. 54, No. 10, 3772-3778, October 2006. doi:10.1109/TMTT.2006.881624
3. Zhao, L. P., X. Zhai, B. Wu, T. Su, W. Xue, and C. H. Liang, "Novel design of dual-mode bandpass filter using rectangular structure," Progress In Electromagnetics Research B, Vol. 3, 131-141, 2008. doi:10.2528/PIERB07121003
4. Chen, Y. W., Y. J. Liu, and M. H. Ho, "The quasi-elliptic bandpass filter using quarter-wavelength stepped impedance resonators ," PIERS Online, Vol. 2, No. 6, 605-608, 2006. doi:10.2529/PIERS060823031952
5. Chen, H. and Y. X. Zhang, "A novel and compact UWB bandpass filter using microstrip fork-form resonators," Progress In Electromagnetics Research, PIER 77, 273-280, 2007.
6. Wei, F., L. Chen, X. W. Shi, X. H. Wang, and Q. L. Huang, "Compact UWB bandpass filter with notched band," Progress In Electromagnetics Research C, Vol. 4, 121-128, 2008.
7. Naghshvarian-Jahromi, M. and M. Tayarani, "Miniature planar UWB bandpass filters with circular slots in ground," Progress In Electromagnetics Research B, Vol. 3, 87-93, 2008.
8. Ghorbaninejad, H. and M. Khalaj-Amirhosseini, "Compact bandpass filters utilizing dielectric filled waveguides," Progress In Electromagnetics Research B, Vol. 7, 105-115, 2008. doi:10.2528/PIERB08031101
9. Ismail, A., M. S. Razalli, M. A. Mahdi, R. S. A. R. Abdullah, N. K. Nordin, and M. F. A. Rasid, "X-band trisection substrate-integrated waveguide quadsi-elliptic filter," Progress In Electromagnetics Research, PIER 85, 133-145, 2008.
10. Razalli, M. S., A. Ismail, M. A. Mahdi, and M. N. Hamidon, "Ultra-wide band microwave filter utilizing quarter-wavelength short-circuited stubs," Microwave and Optical Technology Letters, Vol. 50, No. 11, 2981-2983, November 2008. doi:10.1002/mop.23830
11. Razalli, M. S., A. Ismail, M. A. Mahdi, and M. N. Hamidon, "Novel compact microstrip ultra-wideband filter utilizing shortcircuited stubs with less via," Progress In Electromagnetics Research, PIER 88, 91-104, 2008.
12. Razalli, M. S., A. Ismail, M. A. Mahdi, and M. N. Hamidon, "'Via-less' UWB filter using patched microstrip stubs," Journal of Electromagnetic Waves and Applications, Vol. 23, 377-388, 2009. doi:10.1163/156939309787604508
13. Kouzaev, G. A., M. J. Deen, N. K. Nikolova, and A. H. Rahal, "Cavity models of planar components grounded by via-holes and their experimental verification," IEEE Transactions on Microwave Theory and Techniques, Vol. 54, 1033-1042, 2006. doi:10.1109/TMTT.2005.864137
14. Gupta, K. C., R. Garg, I. Bahl, and P. Bhartis, Microstrip Lines and Slotlines, Artech House, Boston, 1996.
15. Collin, R. E., Foundations for Microwave Engineering, J. Wiley & Sons Inc., New Jersey, 2001.
16. Schneider, M. V., "Microstrip lines for microwave integrated circuits," Bell System Tech. J., Vol. 48, 1422-1444, 1969.
17. Hammerstard, E. O. and O. Jensen, "Accurate models for microstrip computer-aided design," IEEE MTT-S Digest, 407-409, 1980.
18. Hong, J. S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, J. Wiley & Sons Inc., New York, 2001.
19. Pozar, D. M., Microwave Engineering, J. Wiley & Sons Inc., New York, 1998.