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A miniaturized quad‐band bandstop filter with high selectivity based on shunt‐connected, T‐shaped stub‐loaded, stepped‐impedance resonators
Author(s) -
Adhikari Kishor Kumar,
Kim Nam Young
Publication year - 2015
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.29046
Subject(s) - stub (electronics) , resonator , electrical impedance , microwave , materials science , passband , microstrip , center frequency , band pass filter , return loss , optoelectronics , shunt (medical) , stopband , acoustics , electrical engineering , engineering , physics , telecommunications , cardiology , medicine , antenna (radio)
This letter presents a microstrip quad‐band bandstop filter (QBBSF) with a miniaturized size and high selectivity. The structure of the proposed QBBSF consists of two‐folded, shunt‐connected trisection stepped‐impedance resonators (TSSIRs). One of these TSSIRs, which operates on the second and fourth central frequencies, has been embedded inside another TSSIR operating at the first and third central frequencies of the proposed QBBSF. Characterized by equivalent circuit analysis and full‐wave EM simulations, each TSSIR has been miniaturized by a T‐shaped stub load. The main advantage of the proposed QBBSF lies in its central frequencies, which can be adjusted conveniently within a wide range by varying parameters of TSSIRs, the positions, and dimensions of the stub loads. A protocol QBBSF with a compact size of 0.0115 λ g 2 operating at central frequencies of 1.90, 3.32, 5.77, and 6.75 GHz was designed, simulated, and fabricated to verify the proposed method. The measured minimum stop band return loss of 21.4 dB and maximum pass band insertion loss of 0.66 dB indicated the excellent in‐band and out of band selectivity of the proposed QBBSF. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1129–1132, 2015