Compact Metamaterial Microstrip Low-Pass Filter

Sudhakar Sahu, Rabindra Kishore Mishra, Dipak Ranjan Poddar

.

DOI: 10.4236/jemaa.2011.310063                

Abstract

Complimentary hexagonal-omega structures are used to design compact, low insertion loss (IL), low pass filter with sharp cut-off. It has been designed for improvement of roll-off performance based on both μ and ε negative property of the complimentary hex-omega structure while maintaining the filter pass-band performance. By properly designing and loading the hexagonal-omega structure in the ground of microstrip line not only improve the roll-off of the low pass filter, but also reduced the filter size. The simulated results indicate that the proposed filter achieves a flat pass band with no ripples as well as selectivity of 19.68 dB/GHz, corresponding to 5-unit cells hex-omega structures. This significantly exceeds the 5.6 dB/GHz selectivity of the conventional low pass filter design, due to sub-lambda dimensions of the hex-omega structure. A prototype filter implementing area is: 0.712λg x 0.263λg, λg being the guided wavelength at 3-dB cut-off frequency (fc). The proposed filter has a size smaller by 36.2%.

Keywords

Hex-Omega Structure, Microstrip Low-Pass Filter, Metamaterial, Sharp Cut-Off

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	D. Ahn, J.-S. Kim, C.-S. Kim, J. Qian, and T. Itoh, “A Design of the Low-Pass Filter Using the Novel Microstrip Defected Ground Structure,” IEEE Transactions on Microwave Theory and Techniques, Vol.49, No.1, 2001, pp. 86-91. doi:10.1109/22.899965
[2]	J. Garcia-Garcia, F. F. Martin, J. Bonache, et al., “Stepped-Impedance Low Pass Filter with Spurious Pass Band Suppression,” Electronic Letter, Vol. 40, No. 14, 2004, pp. 881-883. doi:10.1049/el:20040560
[3]	J. W. Sheen, “Compact semi-Lumped Low-Pass Filter for Harmonics and Spurious Suppression,’’ IEEE Microwave Wireless Component Letter, Vol. 10, No. 3, 2000, pp. 92-93.
[4]	W. H. Tu and K. Chang, “Compact Microstrip Low-Pass Filter with Sharp-Rejection,” IEEE Microwave Wireless Component Letter, Vol. 15, No. 6, 2005, pp. 404-406. doi:10.1109/LMWC.2005.850479
[5]	V. G. Veselago, “The Electrodynamics of Substances with Simultaneous Negative Values of ε and μ,” Soviet Physics Uspekhi, Vol. 10, No. 4, 1968, pp. 509-514. doi:10.1070/PU1968v010n04ABEH003699
[6]	J. Bonache, M. Gil, I. Gil, J. Garcia-Garcia and F. Martin, “On the Electrical Characteristics of Complementary Metamaterial Resonators,” IEEE Microwave and Wireless Components Letters, Vol. 16, No. 10, 2006, pp. 543- 545. doi:10.1109/LMWC.2006.882400
[7]	J. Garcia-Garcia, F. F. Martin, J. Bonache, et al., ‘Microwave Filters with Improved Stopband Based on Sub- Wavelength Resonators,” Microwave and Optical Technology Letter, Vol. 46, No. 3, 2005, pp. 283-285.
[8]	J. B. Pendry, A. J. Holden, D. J. Robbins, R. Marques, F. Martin and M. Sorolla, ‘Effective Negative-ε Stop-Band Microstrip Lines Based on Complementary Split-Ring Resonators,” IEEE Microwave Wireless Component Letter, Vol. 14, No. 6, 2004, pp. 280-282. doi:10.1109/LMWC.2004.828029
[9]	J. D. Baena, J. J. Bonache, F. F. Martin, R. Marques, et al., ‘Equivalent–Circuit Models for Split Ring Resonators Coupled to Planar Transmission Lines,” IEEE Transaction on Microwave Theory and Techniques, Vol. 53, No. 4, 2005, pp. 1451-1461. doi:10.1109/TMTT.2005.845211
[10]	N. Engheta and R. W. Ziolkowsky, “Metamaterial: Phy- sics and Engineering Explorations,” Wiley, Hoboken, 2006.
[11]	C. Caloz and T. Itoz, “Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications,” Wiley, Hoboken, 2006.
[12]	S. Sahu, R. K. Mishra and D. R. Poddar, “Design of DNG Metamaterial Using Hexagonal Omega Structure,” National Symposium on Antenna and Propagation, Cochin, 29-31December 2008.
[13]	D. M. Pozar, “Microwave Engineering,” Wiley, Hoboken, 2005.
[14]	J. L. Li, S. W. Qu and Q. Xue, “Compact Microstrip Lowpass Filter with Sharp Roll-Off and Wide Stop- Band,” IEE Electronics Letters, Vol. 45, No. 2, 2009, pp. 110-111. doi:10.1049/el:20093246
[15]	R. W. Ziolkowski, “Design, Fabrication, and Testing of Double Negative Metamaterials,” IEEE Transactions on Antenna and Propagation, Vol. 51, No. 7, 2003, pp. 1516-1529. doi:10.1109/TAP.2003.813622
[16]	A. M. Nicolson and G. F. Ross, “Measurement of the Intrinsic Properties of Materials by Time Domain Techniques,” IEEE Transactions on Instrumentation and Measurement, Vol. 19, No. 4, 1970, pp. 377-382. doi:10.1109/TIM.1970.4313932
[17]	W. B. Weir, “Automatic Measurement of Complex Dielectric Constant and permeability at Microwave Frequencies,” Proceedings of the IEEE, Vol. 62, No. 1, 1974, pp. 33-36. doi:10.1109/PROC.1974.9382
[18]	P. K. Kadaba, “Simultaneous Measurement of Complex Permittivity and Permeability at Microwave Frequencies,” IEEE Transaction on Instrumentation and Measurement, Vol. 33, No. 4, 1984, pp. 336-340. doi:10.1109/TIM.1984.4315236
[19]	D. K. Ghodgaonkar, V. V. Varadan and V. K. Varadan, “Free-Space Measurement of Complex Permittivity and Permeability at Microwave Frequencies,” IEEE Transaction on Instrumentation and Measurement, Vol. 39, No. 2, 1990, pp. 387-394. doi:10.1109/19.52520
[20]	J. S. Hong and M. J. Lancaster, “Microstrip Filters for RF/Microwave Applications,” Wiley, New York, 2001. doi:10.1002/0471221619
[21]	J. Wang, L. J. Xu, S. Zhao, Y. X. Guo and W. Wu, “Compact Quasi-Elliptic Microstrip Lowpass Filter with Wide Stopband,” IEE Electronics Letters, Vol. 46, No. 20, 2010, pp. 1384-1385.
[22]	C. W. Tang and M. G. Chen, “Design of Microstrip Lowpass Filters with Wide Stopband and High Attenuation,” IEE Electronics Letters, Vol. 46, No. 21, 2010, pp. 1445-1447. doi:10.1049/el.2010.2147
[23]	C.-W.Tang and S.-C.Yang, “Employing Complementary Split-Ring Resonators for the Wide Stopband Microstrip Lowpass Filter Design,” Microwave and Optical Technology Letters, Vol. 52, No. 11, 2010, pp. 2592-2594. doi:10.1002/mop.25541