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A thin and short VHF wideband filter using CPW CRLH transmission‐line
Author(s) -
Lee Changhyeong,
Kahng Sungtek
Publication year - 2018
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.21415
Subject(s) - wideband , insertion loss , coplanar waveguide , transmission line , electrical engineering , bandwidth (computing) , return loss , filter (signal processing) , engineering , telecommunications , electronic engineering , optoelectronics , materials science , microwave , antenna (radio)
This article proposes a thin and short VHF wideband filter. As background information, wireless sensor network modules on power cables and wearable equipment likely need placement on cylindrical surfaces and operation in a wide VHF‐band. This implies that to meet the aforementioned necessity, wireless components like filters should be conformal to curved surfaces and work in a wideband. There occur two challenges which are physical flexibility and wideband in VHF. To overcome the difficulties at once, a coplanar‐waveguide composite right/left‐handed transmission‐line (CPW CRLH‐TL) is presented as the flexible printed circuit board (FPCB) structure. The zeroth‐order resonator (ZOR) CRLH‐TL filter of 0.248 × 0.025λ g formed on the hosting FPCB plane of 0.63 × 0.26λ g , which is not realizable with microstip lines and conventional CPWs. The CRLH filter comprising CPW interdigital lines and two shunt inductors determined for an extremely thin ZOR at 160 MHz provides the fractional bandwidth of 140% as an unprecedentedly broadband, insertion loss of 1.5 dB, and return loss of 16 dB in the measurement which complies with circuit and EM simulations. Besides, when this flexible filter wraps around a cylindrical object of different curvatures, the wideband performance in the VHF region is robust against the bending effect.