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Compact ultra‐wideband bandpass filter with variable notch characteristics based on transversal signal‐interaction concepts
Author(s) -
Mirzaee Milad,
Virdee Bal S.,
Noghanian Sima
Publication year - 2014
Publication title -
international journal of rf and microwave computer‐aided engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 39
eISSN - 1099-047X
pISSN - 1096-4290
DOI - 10.1002/mmce.20798
Subject(s) - passband , band stop filter , band pass filter , insertion loss , physics , prototype filter , bandwidth (computing) , filter (signal processing) , electronic engineering , acoustics , computer science , telecommunications , low pass filter , optics , engineering , electrical engineering
A novel technique is presented to design highly compact microstrip ultra‐wideband (UWB) bandpass filters that exhibit high selectivity quasi‐elliptical response. The design is based on transversal signal‐interaction concepts that enable the inclusion of single or dual notch‐bands within the filter's passband to eliminate interference from other services that coexist within the UWB spectrum. The filter configuration comprises of two transmission paths which include folded T‐shaped stepped impedance resonators (SIRs) that are capacitively coupled with the input/output lines to enable signal transmission. It is shown that by combining the filters of different passband centre frequencies an UWB filter can be realised with either a single‐ or dual‐notch function. The theoretical performance of the filter is corroborated via measurements to confirm that the proposed filter exhibits UWB passband of 123% for a 3 dB fractional bandwidth, a flat group‐delay with maximum variation of less than 0.3 ns, passband insertion loss less than 0.94 dB, high selectivity, a sharp rejection notch‐band with attenuation of −23 dB, and a good overall out‐of‐band performance. Furthermore, the filter occupies a significantly small area of 94 mm 2 compared with its classical counterparts. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:549–559, 2014.