A quasi-elliptic wideband bandpass filter using a novel multiple-mode resonator constructed by an asymmetric compact microstrip resonant cell

This article proposes a novel wideband bandpass filter using a novel microstrip multiple‐mode resonator (MMR). This MMR is composed of a section of open‐ended microstrip‐line and an asymmetric compact microstrip resonant cell (ACMRC) connected to the open‐ended microstrip‐line section at its central point. Its three resonant modes are employed in this article to construct the wider passband of the proposed filter. In addition, multiple transmission zeros brought by the ACMRC will help to create a quasi‐elliptic response and extend the stopband. Finally, a demonstration filter is designed, fabricated and tested to show the validity of the proposed structure. Both simulated and measured results show that the proposed filter has a good performance. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 713–714, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24168