Wideband bandpass filter with high selectivity based on dual-mode DGS resonator.

A wideband bandpass filter based on dual-mode defected ground structure resonator (DGSR) is designed and effectively analysed by utilising the even-/odd-mode theory and equivalent circuit models. The lower and upper cutoff frequencies of the filter can be independently tuned by adjusing the even- and odd-mode resonant frequencies of the dual-mode DGSR, respectively. The fabricated prototype is centred at 2.27 GHz with a wide bandwidth (FBW 63.4%), low insertion loss (0.386 dB), high selectivity and wide stopband. The attenuation slopes in the lower and upper passband transitions are 108.5 and 136.9 dB/GHz, respectively. The stopband rejection is better than 22 dB up to 6 GHz (2.6 f₀). © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2300-2303, 2016 [ABSTRACT FROM AUTHOR]