Microstrip Open-Loop Ring Bandpass Filter Using Open Stubs for Harmonic Suppression Conference Paper uri icon


  • Improved harmonic suppression is achieved by adding small shunt open stubs to a conventional open-loop bandpass filter. A design curve for the shunt open stub is derived using the ABCD matrix calculation. The insertion loss of the four-pole filter is 3 dB at 1.8385 GHz, and the return loss is better than 10 dB within 1.7935-1.8835 GHZ. The suppression of the modified filter is better than 30 dB below 1.7 GHz and between 2-6 GHz, while the conventional filter shows a spurious passband at 3.7 GHz. © 2006 IEEE.

author list (cited authors)

  • Tu, W., Li, H., Michalski, K. A., & Chang, K.

citation count

  • 11

publication date

  • January 2006