Compact Multi-section Microstrip Low Pass Filter at the 3dB cut off frequency of 2. 4 GHz is presented in this paper. The analysis of a low pass filter and its response with the variation of length is also included. The return loss is better than 15 dB and insertion loss is of less than 0. 7 dB from dc to 3. 08 GHz and rejection is better than 20 dB from 3. 15GHz to 8. 03GHz. The presented filter shows good characteristics in the passband and the stopband. The results indicate that the LPF has many desirable features, such as compact size, low insertion loss, very sharp transition bands, and wide stopband. These are all good characteristics applicable in modern communication systems.

1. Wen-Hua Tu, Kai Chang "Compact microstrip Low Pass Filter with sharp rejection",IEEE Microwave and Wireless components letters , VOL 15 , NO 6 , June 2005.
2. D. Ahn, J. S. Park, C. S. Kim, J. Kim, Y. Qian, and T. Itoh, design of the low-pass filter using the novel microstrip defected ground structure, IEEE Trans Microwave Theory Tech 49 (2001), 86–93.
3. M. K. Mandal and S. Sanyal, A novel defected ground structure for planar circuits, IEEE Microwave Wireless Compon Lett 16 (2006), 93–95.
4. B. Wu, B. Li, and C. Liang, Design of lowpass filter using novel split-ring resonator defected ground structure, Microwave Opt Technol Lett 49 (2007), 288–291.
5. X. Chen, L. Wang, L. Weng, and X. Shi, Compact lowpass filterusing novel elliptic shape DGS, Microwave Opt Technol Lett 51(2009), 1088–1091.
6. S. S. Karthikeyan and R. S. Kshetrimayum, Compact widebandbandpass filter using open slot split ring resonator and CMRC,Prog Electromagn Res Lett 10 (2009), 39–48.
7. P. Kurgan and M. Kitlinski, Novel microstrip low-pass filters with fractal defected ground structures, Microwave Opt Technol Lett 10 (2009), 2493–2497.
8. L. Li, Z. -F. Li, and Q. -F. Wei, Compact and selective lowpass filter with very wide stopband using tapered compact microstrip resonant cells, Electron Lett 45 (2009).
9. K. Deng, Q. Xue, and W. Che, Improved compact microstrip resonancecell lowpass filter with wide stopband characteristics, Electron Lett 43 (2007).
10. D. M. Pozar, Microwave Engineering. New York: Wiley, 1998, ch. 8.
11. J. -W. Sheen, "A compact semi-lumped low-pass filter for harmonics and spurious suppression," IEEE Microw. Wireless Compon. Lett. , vol. 10, no. 3, pp. 92–93, Mar. 2000.
12. Y. -W. Lee, S. -M. Cho, G. -Y. Kim, J. -S. Park, D. Ahn, and J. -B. Lim, "A design of the harmonic rejection coupled line low-pass filter with attenuation poles," in IEEE MTT-S Int. Dig. , 1999, pp. 682–685.
13. L. -H. Hsieh and K. Chang, "Compact elliptic-function low-pass filters using microstrip stepped-impedance hairpin resonators," IEEE Trans. Microwave Theory Tech. , vol. 51, no. 1, pp. 193–199, Jan. 2003.
14. J. -T. Kuo and J. Shen, "A compact distributed low-pass filter with wide stopband," in Proc. Asia-Pacific Microwave Conf. , vol. 1, 2001, pp. 330–333.
15. Zeland Software, Inc. , Fremont, CA, Std. IE3D Ver. 10. 1, Dec. 2003.
16. J. S. Won, "Microstrip tapped-line filter design," IEEE Trans. MicrowaveTheory Tech. , vol. MTT-27, pp. 44–50, Jan. 1979.
17. M. Sagawa, K. Takahashi, and M. Makimot, "Miniaturized hairpin resonator filters and their application to receiver front-end MIC's," IEEE Trans. Microwave Theory Tech. , vol. 37, pp. 1991–1997, Dec. 1989.
18. J. T. Ku, M. J. Maa, and P. H. Lu, "A microstrip elliptic function filter with compact miniaturized hairpin resonator," IEEE Microwave Guided Wave Lett. , vol. 10, pp. 94–95, Mar. 2000.
19. S. Y. Lee and C. M. Tsai, "New cross-coupled filter design using improved hairpin resonators," IEEE Trans. Microwave Theory Tech. , vol. 48, pp. 2482–2490, Dec. 2000.
20. J. T. Kuo, M. J. Maa, and P. H. Lu, "Microstrip elliptic function filter with compact miniaturized hairpin resonators," in Asia–Pacific Microwave Conf. , 1999, pp. 860–864.
21. A. Enokihara, K. Setsune, M. Sagawa, and M. Makimoto, "High-T bandpass filter using miniaturized microstrip hairpin resonator," Electron. Lett. , vol. 28, no. 20, pp. 1925–1927, Sept. 1992.
22. D. M. Pozar, Microwave Engineering. New York: Wiley, 1998, vol. 2nd, ch. 8.
23. I. Rumsey, M. Piket-May, and P. K. Kelly, "Photonic bandgap structure used as filters in microstrip circuits," IEEE Microwave Guided Wave Lett. , vol. 8, no. 10, pp. 336–338, Oct. 1998.
24. D. Ahn, J. S. Park, C. S. Kim, J. Kim, Y. Qian, and T. Itoh, "A design of the low-pass filter using the novel microstrip defected ground structure," IEEE Trans. Microwave Theory Tech. , vol. 49, pp. 86–92, Jan. 2001.
25. J. W. Sheen, "A compact semilumped low-pass filter for harmonics and spurious suppression," IEEE Microwave Guided Wave Lett. , vol. 10, pp. 92–93, Mar. 2000.
26. L. -H. Hsieh and K. Chang, "Compact lowpass filter using steppedimpedance hairpin resonator," Electron. Lett. , vol. 37, no. 14, pp. 899–900, July 2001.
27. F. Giannini, M. Salerno, and R. Sorrentino, "Design of low-pass elliptic filters by means of cascaded microstrip rectangular elements," IEEE Trans. Microwave Theory Tech. , vol. 30, pp. 1348–1353, Sept. 1982.
28. H. Yabuki, M. Sagawa, and M. Makimoto, "Voltage controlled push–push oscillators using miniaturized hairpin resonators," in IEEE MTT-S Int. Microwave Symp. Dig. , 1991, pp. 1175–1178.
29. C. BrianWadell, Transmission Line Design Handbook. Norwood, MA: Artech House, 1991, p. 321.
30. P. R. Geffe, Simplified Modern Filter Design. NewYork: John F. Rider, 1963, sec. Appendix 4.
31. G. Mazzarella, "CAD modeling of interdigitated structures," IEEETrans. Educ. , vol. 42, pp. 81–87, Feb. 1999.

Microstrip Lows Pass Filter Sharp Transition Band Wide Stopband.