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Ultra-Compact Band-Pass Filter at Low Frequency of Operation

By Basil J. Paul and Shanta Mridula
Progress In Electromagnetics Research Letters, Vol. 111, 17-25, 2023


An ultra-compact band-pass filter is presented in this paper. The filter is designed to operate in the medical implants communication service (MICS) band ranging from 401 MHz to 406 MHz. The filter is designed on a Rogers RT/duroid substrate with εr = 2.94 and tanδ = 0.0012. The overall size of the proposed filter is only 30.6 mm x 18.5 mm (0.058λg x 0.035λg), making it suitable for compact, portable devices. An equivalent circuit model is also proposed for the analysis of the filter geometry. From the circuit model, it can be concluded that the filter exhibits the characteristics of a dual-composite right left-handed (D-CRLH) transmission line. This is also confirmed from the dispersion characteristics. The salient features of the proposed filter include ultra-compactness at low operating frequency, harmonic suppression of 3.7 times of the passband frequency, fractional bandwidth of 4.45%, and good roll-off rate of 297.6 dB/GHz in the lower stopband and 116.4 dB/GHz in the upper stopband.


Basil J. Paul and Shanta Mridula, "Ultra-Compact Band-Pass Filter at Low Frequency of Operation," Progress In Electromagnetics Research Letters, Vol. 111, 17-25, 2023.


    1. Mandal, A. and T. Moyra, "Compact low-pass filter (LPF) with wide harmonic suppression using interdigital capacitor," Frequenz, Vol. 77, No. 1-2, 1-8, 2022.

    2. Fathi, E., F. Setoudeh, and M. B. Tavakoli, "Design and fabrication of a novel multilayer bandpass filter with high-order harmonics suppression using parallel coupled microstrip filter," ETRI Journal, Vol. 44, No. 2, 260-273, 2021.

    3. Das, T. K. and S. Chatterjee, "Improved second harmonic suppression in a compact coupled-line bandpass filter with triangular corrugations," Microsystem Technologies, Vol. 25, 1945-1956, 2018.

    4. Idris, I. H., M. R. Hamid, K. Kamardin, M. K. A. Rahim, F. Zubir, and H. A. Majid, "Band-pass filter with harmonics suppression capability," International Journal of Electrical and Computer Engineering, Vol. 8, No. 4, 2512-2520, 2018.

    5. Das, T. K. and S. Chatterjee, "Harmonic suppression by using T-shaped spur-line in a compact hairpin-line bandpass filter," Radioengineering, Vol. 30, No. 2, 296-303, 2021.

    6. Chaimool, S. and P. Akkaraekthalin, "Miniaturized wideband bandpass filter with wide stopband using metamaterial-based resonator and defected ground structure," Radioengineering, Vol. 21, No. 2, 611-616, 2012.

    7. Lotfi-Neyestanak, A. A. and A. Lalbakhsh, "Improved microstrip hairpin-line bandpass filters for spurious response suppression," Electronics Letters, Vol. 48, No. 14, 858-859, 2012.

    8. Chen, W.-L. and G.-M.Wang, "Effective design of novel compact fractal-shaped microstrip coupled-line bandpass filters for suppression of the second harmonic," IEEE Microwave and Wireless Components Letters, Vol. 19, No. 2, 74-76, 2009.

    9. Duraiswamy, P., "Compact capacitor-loaded tunable microstrip bandpass filter for low-frequency applications," Journal of The Institution of Engineers (India): Series B, Vol. 103, 1453-1457, 2022.

    10. Jovanovic, S. and A. Nesic, "A new microstrip band-pass filter for UHF range," TELSIKS 2005 --- 2005 UTH International Conference on Telecommunication in Modern Satellite, Cable and Broadcasting Services, Vol. 12005, 167-169, Nis, Serbia, 2005.

    11. Hasan, A. B., M. T. Rahman, A. Kahhar, T. Trina, and P. K. Saha, "Design of miniature type parallel coupled microstrip hairpin filter in UHF range," AIP Conference Proceedings, Vol. 1919, 020017-1-020017-7, 2017.

    12. Peng, L. and X. Jiang, "Ultra-compact UHF band-pass filter designed by archimedes spiral capacitor and shorted-loaded stubs," Frequenz, Vol. 69, No. 1-2, 71-73, 2014.

    13. Jang, G. and S. Kahng, "Compact metamaterial zeroth-order resonator bandpass filter for a UHF band and its stopband improvement by transmission zeros," IET Microw. Antennas Propag., Vol. 5, No. 10, 1175-1181, 2011.

    14. Choudhary, D. K. and R. K. Chaudhary, "A compact via-less metamaterial wideband bandpass filter using split circular rings and rectangular stub," Progress In Electromagnetics Research Letters, Vol. 72, 99-106, 2018.

    15. Caloz, C., "Dual composite right left handed (D-CRLH) transmission line metamaterial," IEEE Microwave and Wireless Components Letters, Vol. 16, No. 11, 585-587, 2006.

    16. Garg, P. and P. Jain, "Design and analysis of a bandpass filter using dual composite right/left handed (D-CRLH) transmission line showing bandwidth enhancement," Wireless Personal Communications, Vol. 120, 1705-1720, 2021.

    17. Hoseini, S. M. S. N., R. Zaker, and K. Monfaredi, "A microstrip folded compact wideband band-pass filter with wide upper stopband," ETRI Journal, Vol. 43, No. 6, 957-965, 2021.

    18. Wu, G.-C., G.-M. Wang, and Y.-W. Wang, "Novel simplified dual-composite right/left handed transmission line and its application in bandpass filter with dual notch bands," Progress In Electromagnetics Research C, Vol. 44, 123-131, 2013.

    19. Shen, G., X. Wang, W. Che, W. Feng, W. Yang, and K. Deng, "Miniaturized high-performance D-CRLH resonator and filter based on accurate equivalent circuit model," International Workshop on Electromagnetics: Applications and Student Innovation Competition (iWEM), 1-3, Hsinchu, Taiwan, 2015.

    20. Shen, G., W. Che, Q. Xue, and W. Yang, "Characteristics of dual composite right/left-handed unit cell and its applications to bandpass filter design," IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 65, No. 6, 719-723, 2018.

    21. Tong, W., Z. Hu, H. Zhang, C. Caloz, and A. Rennings, "Study and realisation of dual-composite right/left-handed coplanar waveguide metamaterial in MMIC technology," IET Microwaves, Antennas & Propagation, Vol. 2, No. 7, 731-736, 2008.

    22. Belenguer, A., J. Cascon, A. L. Borja, H. Esteban, and V. E. Boria, "Dual composite right-/left-handed coplanar waveguide transmission line using inductively connected split-ring resonators," IEEE Transactions on Microwave Theory and Techniques, Vol. 60, No. 10, 3035-3042, 2012.

    23. Daw, A. F., P. A. Fawzey, and M. N. Adly, "Quad-band resonator depends on CRLH/D-CRLH structures," Microwaves & RF (MWRF), October 2019, available online: https://www.mwrf.com/technologies/components/article/21849975/quadband-resonator-depends-on-crlhdcrlh-structures.

    24. Daw, A. F., M. A. Abdalla, and H. M. Elhennawy, "New configuration for multiband ultra compact gap resonator based D-CRLH," IEEE Middle East Conference on Antennas and Propagation (MECAP), 1-4, 2016.

    25. Abdalla, M. A. and A. Fouad, "Integrated filtering antenna based on D-CRLH transmission lines for ultra-compact wireless applications," Progress In Electromagnetics Research C, Vol. 66, 29-38, 2016.

    26. Paul, B. J., S. Mridula, B. Paul, and P. Mohanan, "Metamaterial inspired CPW fed compact low-pass filter," Progress In Electromagnetics Research C, Vol. 57, 173-180, 2015.

    27. Paul, B. J., S. Mridula, A. Pradeep, and P. Mohanan, "Design of an ultra compact antenna for low frequency applications," Progress In Electromagnetics Research Letters, Vol. 105, 95-102, 2022.

    28. Hong, J.-S., Microstrip Filters for RF/Microwave Applications, John Wiley & Sons, 2011.

    29. Varadan, V. K., K. J. Vinoy, and K. A. Jose, RF MEMS and Their Applications, John Wiley & Sons, 2003.

    30. Olaode, O. O., W. D. Palmer, and W. T. Joines, "Effects of meandering on dipole antenna resonant frequency," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 122-125, 2012.

    31. Olaode, O. O., W. D. Palmer, and W. T. Joines, "Characterization of meander dipole antennas with a geometry-based, frequency-independent lumped element model," IEEE Antennas and Wireless Propagation Letters, Vol. 11, 346-349, 2019.

    32. Caloz, C. and T. Itoh, Electromagnetic Metamaterials: Transmission Line Theory and Microwave Applications, John Wiley & Sons, 2006.

    33. Ryu, Y.-H., J.-H. Park, J.-H. Lee, J.-Y. Kim, and H.-S. Tae, "DGS dual composite right/left handed transmission line," IEEE Microwave and Wireless Components Letters, Vol. 18, No. 7, 434-436, 2008.

    34. Lu, K., G.-M. Wang, and B. Tian, "Design of dual-band branch-line coupler based on shunt open-circuit DCRLH cells," Radioengineering, Vol. 22, No. 2, 618-623, 2013.

    35. Eisenstadt, W. R. and Y. Eo, "S-parameter-based IC interconnect transmission line characterization," IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 15, No. 4, 483-490, 1992.