access icon free Design of ultra-wideband bandstop filter using defected ground structure

© The Institution of Engineering and Technology
Received 05/05/2013, Published

A simple wideband bandstop filter which yields equal ripples in the stopband is described. The filter comprises only two resonators and a connecting transmission line. Ultra-wide stopband characteristic is achieved by realising three transmission zeros near the passband edges. Stopband rejection depth and bandwidth can be controlled by impedances of the configuration. The defected ground structure is chosen to realise the high impedance line. To validate the proposed topology, a compact microstrip bandstop filter centred at 1.5 GHz with a measured 20 dB rejection bandwidth of about 139% is fabricated.

Inspec keywords: poles and zeros; defected ground structures; microstrip filters; ultra wideband technology; band-stop filters

Other keywords: ultrawide stopband characteristic; connecting transmission line; frequency 1.5 GHz; defected ground structure; resonators; transmission zeros; ultrawideband bandstop filter; stopband rejection depth; compact microstrip bandstop filter; high impedance line; passband edges

Subjects: Filters and other networks; Waveguide and microwave transmission line components; General circuit analysis and synthesis methods

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