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Compact low‐pass stepped impedance filters with enhanced out of band response
Author(s) -
Elhalabi Heba,
Issa Hamza,
Pistono Emmanuel,
Kaddour Darine,
AbouChahine S.,
Ferrari Phillipe
Publication year - 2017
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.30635
Subject(s) - microstrip , materials science , electrical impedance , characteristic impedance , filter (signal processing) , optoelectronics , low pass filter , dielectric , substrate (aquarium) , acoustics , band pass filter , electric power transmission , electronic engineering , electrical engineering , physics , engineering , oceanography , geology
This article presents slow‐wave microstrip transmission lines based on a double‐layer PCB substrate for miniaturized and high‐rejection low‐pass filters design. The slow‐wave effect is obtained by inserting metallic via rows within the lower substrate layer. Realized slow‐wave microstrip transmission lines exhibit a high effective dielectric constant of 7.4 instead of 3 for classical microstrip transmission lines. Based on this concept, miniaturized high‐rejection 7th‐order low‐pass stepped‐impedance filters with a cut‐off frequency of 2.45 GHz were designed, fabricated and measured. Measurement results are in good agreement with simulations. Thanks to the slow‐wave microstrip lines, the size of the realized filters is reduced by 65% as compared to a classical filter prototype, without degrading electrical performances.