Compact balanced UWB bandpass filter with one narrow notched band

A compact balanced ultra-wideband bandpass filter (BPF) with one sharply notched band is presented in this article. The proposed BPF based on microstrip-to-slotline transition obtains favorable uniform differential-mode response and good common-mode suppression. Moreover, one narrow notched band with a 3 dB bandwidth of 6.8% is realized by introducing one coupled half-wavelength resonator. The fabricated filter has a more than 25% size reduction compared to the designs reported in open literature. The predicted results are compared with measured ones and good agreement is achieved. Copyright © 2014 Wiley Periodicals, Inc