ETRI Journal

Electronics and Telecommunications Research Institute (한국전자통신연구원)
권호 표지
DOI QR코드

DOI QR Code

Microstrip Lowpass Filter with Very SharpTransition Band Using T-Shaped, Patch, and Stepped Impedance Resonators

  • Hayati, Mohsen (Electrical Engineering Department, Faculty of Engineering, Razi University) ;
  • Sheikhi, Akram (Electrical Engineering Department, Faculty of Engineering, Razi University)
  • Received : 2012.07.17
  • Accepted : 2012.12.20
  • Published : 2013.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of -3 dB and -20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3-dB cut-off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than -20 dB is obtained while achieving a compact size with a wide stopband.

Keywords

References

  1. J.S. Hong and M.J. Lancaster, Microstrip Filters for RF/Microwave Applications, NY: Wiley, 2001.
  2. D.M. Pozar, Microwave Engineering, 2nd ed., NY: Wiley, 1998.
  3. A. Balalem et al., "Quasi-Elliptic Microstrip Low-Pass Filters Using an Interdigital DGS Slot," IEEE Microw. Wireless Compon. Lett., vol. 17, no. 8, Aug. 2007, pp. 586-588. https://doi.org/10.1109/LMWC.2007.901769
  4. S.W. Ting, K.W. Tam, and R.P. Martins, "Miniaturized Microstrip Lowpass Filter with Wide Stopband Using Double Equilateral U-Shaped Defected Ground Structure," IEEE Microw. Wireless Compon. Lett., vol. 16, no. 5, May 2006, pp. 240-242. https://doi.org/10.1109/LMWC.2006.873592
  5. J.-L. Li, S.-W. Qu, and Q. Xue, "Compact Microstrip Lowpass Filter with Sharp Roll-Off and Wide Stop-Band," Electron. Lett., vol. 45, no. 2, Jan. 2009, pp. 110-111. https://doi.org/10.1049/el:20093246
  6. M. Hayati, A. Sheikhi, and A. Lotfi, "Compact Lowpass Filter with Wide Stopband Using Modified Semi-elliptic and Semicircular Microstrip Patch Resonator," Electron. Lett., vol. 46, no. 22, Nov. 2010, pp. 1507-1509. https://doi.org/10.1049/el.2010.2367
  7. L. Ge, J.P. Wang, and Y.-X. Guo, "Compact Microstrip Lowpass Filter with Ultra-wide Stopband," Electron. Lett., vol. 46, no. 10, May 2010, pp. 689-691. https://doi.org/10.1049/el.2010.0357
  8. J. Wang et al., "Compact Quasi-elliptic Microstrip Lowpass Filter with Wide Stopband," Electron. Lett., vol. 46, no. 20, Sept. 2010, pp. 1384-1385. https://doi.org/10.1049/el.2010.1569
  9. M. Hayati and A. Sheikhi, "Microstrip Lowpass Filter with Very Sharp Transition Band and Wide Stopband," ETRI J., vol. 33, no. 6, Dec. 2011, pp. 986-984.
  10. C.F. Zhang, "Compact and Wide Stopband Lowpass Filter with Novel Comb CMRC," Int. J. Electron., vol. 96, no. 7, July 2009, pp. 749-754. https://doi.org/10.1080/00207210902838610

Cited by

  1. Design of compact microstrip lowpass filter with ultra-wide stopband using modified T-shaped resonator vol.7, pp.6, 2013, https://doi.org/10.1017/s175907871400124x
  2. Compact Lowpass Filter with Ultra-High Figure-of-Merit and Flat Group Delay vol.64, pp.6, 2013, https://doi.org/10.1080/03772063.2017.1381046
  3. A compact lowpass filter with ultra-high figure-of-merit for integrating with Class-F/F−1 power amplifiers vol.99, pp.3, 2019, https://doi.org/10.1007/s10470-018-01387-6
  4. Design, Simulation and Manufacturing Microstrip Low-pass Filter by Wide Stopband and Changing Fast Situation from Passing State to Stopping vol.65, pp.4, 2013, https://doi.org/10.1080/03772063.2018.1433079