PIER Letters
Progress In Electromagnetics Research Letters
ISSN: 1937-6480
Home | Search | Notification | Authors | Submission | PIERS Home | EM Academy
Home > Vol. 35 > pp. 73-81


By M. Hayati, H. A. Memari, and H. Abbasi

Full Article PDF (321 KB)

In this paper, a semicircle ended stub resonator, cascaded to a modified radial patch to design a compact lowpass filter with sharp roll-off and wide stopband is proposed. This filter has 3 dB cutoff frequency at 1.54 GHz. The transition band is only 0.26 GHz from 1.54 GHz to 1.8 GHz with corresponding attenuation levels of -3 dB and -20 dB respectively. Maximum insertion loss is 0.1 dB in the passband, and the stopband bandwidth with the attenuation level better than -20 dB is extended from 1.8 GHz up to 13.93 GHz. So, a wide stopband is achieved. The proposed filter is designed, fabricated and measured, where there is a good agreement between the simulation and measurement results. The results show that a roll-off rate of 65.4 dB/GHz together with a relative stopband bandwidth of 154% with the suppression level of -20 dB is obtained while achieving a high figure of merit (FOM) of 23509.

M. Hayati, H. A. Memari, and H. Abbasi, "Compact Microstrip Lowpass Filter with Sharp Roll-off and Wide Stopband Using Semicircle Ended Stub Resonator," Progress In Electromagnetics Research Letters, Vol. 35, 73-81, 2012.

1. Pozar, D. M., Microwave Engineering, 3rd Ed., Wiley, New York, 2005.

2. Luo, S., L. Zhu, and S. Sun, "Stopband-expanded low pass filters using microstrip coupled-line hairpin units," IEEE Microwave and Wireless Components Letters, Vol. 18, No. 8, 506-508, August 2008.

3. Hayati, M., A. Sheikhi, and A. Lotfi, "Compact lowpass filter with wide stopband using modified semi-elliptic and semi-circular microstrip patch resonator," Electronics Letters, Vol. 46, No. 22, 1507-1509, October 2010.

4. Li, J.-L., S.-W. Qu, and Q. Xue, "Compact microstrip lowpass filter with sharp roll-off and wide stop-band," Electronics Letters, Vol. 45, No. 2, 110-111, January 2009.

5. Chen, J., Z.-B.Weng, Y.-C. Jiao, and F.-S. Zhang, "Lowpass filter design of Hilbert curve ring defected ground structure," Progress In Electromagnetics Research, Vol. 70, 269-280, 2007.

6. Wang, C. J. and T. H. Lin, "A multi-band meandered slotted-ground-plane resonator and its application of low-pass filter," Progress In Electromagnetics Research, Vol. 120, 249-262, 2011.

7. Fallahzadeh, S. and M. Tayarani, "A new microstrip UWB bandpass filter using defected microstrip structures," Journal of Electromagnetic Waves and Applications,, Vol. 24, No. 7, 893-902, 2010.

8. Zhou, J.-M., L.-H. Zhou, H. Tang, Y.-J. Yang, J.-X. Chen, and Z.-H. Bao, "Novel compact microstrip lowpass filters with wide stopband using defected ground structure," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 7, 1009-1019, 2011.

9. Al Sharkawy, M. H., D. Abd El-Aziz, and E. Galal, "A miniaturized lowpass/bandpass filter using double arrow head defected ground structure with centered etched ellipse," Progress In Electromagnetics Research Letter, Vol. 24, 99-107, 2011.

10. Lin, D.-B., I.-T. Tang, and M.-Z. Hong, "A compact quad-band PIFA by tuning the defected ground structure for mobile phones," Progress In Electromagnetics Research B, Vol. 24, 173-189, 2010.

11. Ma, K. and K. S. Yeo, "New ultra wide stopband lowpass filter using transformed radial stubs," IEEE Trans. Microw. Theory Tech., Vol. 59, No. 3, 604-611, 2011.

12. Hong, J. S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, Wiley, New York, 2001.

13. Velidi, V. K. and S. Sanyal, "Sharp roll-off lowpass filter with wide stopband using stub-loaded coupled-line hairpin unit," IEEE Microwave and Wireless Components Letters, Vol. 21, No. 6, 301-303, June 2011.

14. Wang, J., L.-J. Xu, S. Zhao, Y.-X. Guo, and W. Wu, "Compact quasielliptic microstrip lowpass filter with wide stopband," Electronics Letters, Vol. 46, No. 20, 1384-1385, September 2010.

© Copyright 2010 EMW Publishing. All Rights Reserved