Open AccessMiniaturised microstrip lowpass filter with sharp roll‐off and ultra‐wide stopband
Author(s) -
Karimi Gh.,
KhaminHamedani F.,
Siahkamari H.
Publication year - 2013
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2013.2321
Subject(s) - stopband , transition band , cutoff frequency , low pass filter , microstrip , resonator , bandwidth (computing) , elliptic filter , materials science , prototype filter , filter (signal processing) , electronic engineering , optoelectronics , acoustics , optics , physics , telecommunications , engineering , electrical engineering
A new semi‐fractal technique is applied to hairpin microstrip lowpass filters to realise compact size and sharp roll‐off. To achieve wide stopband suppression, both a semi‐fractal hairpin resonator and a U‐shaped resonator are employed in the filter. A demonstration filter with 3 dB cutoff frequency at 1.51 GHz has been designed, fabricated and measured. The results show that a roll‐off of 217.6 dB/GHz with a relative stopband bandwidth of 159.7% (referred to a suppression degree of 32 dB) can be obtained while achieving a high figure‐of‐merit of 44 832.