• DocumentCode
    49159
  • Title

    Compact lowpass filter with wide stopband using coupled rhombic stubs

  • Author

    Bo Zhang ; Shaosheng Li ; Jianming Huang

  • Author_Institution
    Beijing Univ. of Posts & Telecommun., Beijing, China
  • Volume
    51
  • Issue
    3
  • fYear
    2015
  • fDate
    2 5 2015
  • Firstpage
    264
  • Lastpage
    266
  • Abstract
    A compact and high selective lowpass filter (LPF) with wide stopband is presented using coupled rhombic stubs. The proposed LPF unit is constructed by loading a rhombic stub on a transmission line. Then, a folded three-element LPF is proposed to achieve compact size and high selectivity by introducing coupling between adjacent rhombic stubs. The operating mechanism of the filter is investigated and explained, by adopting the physically-based LC-equivalent circuit model. The implemented final LPF exhibits a wide stopband of up to 11.5 fc with a rejection level of better than 35 dB. Furthermore, the final LPF features a compact size of 0.12λg × 0.10λg, where λg is the guide wavelength of fc, and a very high figure-of-merit (FOM) of 27 142.
  • Keywords
    LC circuits; coupled transmission lines; equivalent circuits; low-pass filters; LC-equivalent circuit model; compact lowpass filter; coupled rhombic stubs; folded three-element LPF; transmission line; wide stopband;
  • fLanguage
    English
  • Journal_Title
    Electronics Letters
  • Publisher
    iet
  • ISSN
    0013-5194
  • Type

    jour

  • DOI
    10.1049/el.2014.3490
  • Filename
    7029768