Microstrip stepped-impedance hairpin resonator low-pass filter with defected ground structure

hi this paper, a new microstrip stepped-impedance hairpin resonator (SIR) low-pass filter (LPF) using a defected ground structure (DGS) is proposed. The proposed SIR hairpin low-pass filter using DGS provides a very sharp cutoff frequency response with low insertion loss. Furthermore, the SIR hairpin low-pass filter can provide attenuation poles for the wide-stopband characteristic due to the resonance characteristic of the DGS. Design parameters for the SIR low-pass filter are derived based on stepped-impedance theory and the equivalent-Circuit model for the DGS. The experimental results show excellent agreement with the theoretical simulation results. (C) 2005 Wiley Periodicals, Inc.