Miniaturized notch‐band UWB bandpass filters using interdigital‐coupled feed‐line structure

Two ultrawideband (UWB) bandpass filters (BPFs) using interdigital‐coupled feed‐line structures with different notched frequency bands are presented. The proposed interdigital lines are used, not only to realize strong coupling as feed lines, but also be able to create an adjustable rejection band in the UWB passband without adding any other circuits, which make the overall size of the filter super miniaturized. Two prototypes of the proposed notch‐band UWB BPFs have been fabricated and tested, whose measured results are both in good agreement with the full‐wave simulations. The notched frequency bands of these two UWB BPFs are centered at 5.8 and 8.0 GHz, with attenuation of around 12 and 14 dB, respectively. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2215–2217, 2014