AbstractIn this paper, an improved electromagnetic periodic structure bandpass filter (EPS‐BPF) is designed and analyzed, and its equivalent circuit is also presented. The proposed structure achieves two transmission zeros on both sides of passband, while a good rolling skirt is obtained as well. The measured results show that the filter has a fractional 3‐dB bandwidth of 16%, and its insertion and return losses are −2 and −27 dB at the 5‐GHz center frequency, respectively. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 265–267, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20273