Band-notched balanced UWB BPF with stepped-impedance slotline multi-mode resonator

Ching Her Lee, Chung I.G. Hsu, Chung Jung Chen

Research output: Contribution to journalArticle

67 Citations (Scopus)


This letter presents a new 5 GHz band-notched balanced ultra-wideband (UWB) bandpass filter (BPF), which is designed using a stepped-impedance slotline multi-mode resonator (MMR). To obtain favorable uniform differential-mode (DM) response, a microstrip-to-slotline transition is used as the signal-feeding structure and the first three resonant modes of the slotline MMR are located in the UWB passband. Common-mode (CM) signal rejection is achieved by deploying the slotline MMR in such a way that the quarter-wavelength resonances occurring near the input and output sides of the resonator are well decoupled. Also featured in this design is the blocking of unwanted WLAN signals, which is achieved by loading the input feed-lines with a stepped-impedance microstrip stub to create a notch-band centered at 5.5 GHz. The designed BPF has a measured minimum DM insertion loss of 0.83 dB in the UWB passband, in which the measured CM suppression is larger than 18.85 dB.

Original languageEnglish
Article number6172617
Pages (from-to)182-184
Number of pages3
JournalIEEE Microwave and Wireless Components Letters
Issue number4
Publication statusPublished - 2012 Apr 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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