Design of Microstrip Low-Pass Filter Based on Six-Slit-Ring DGS
A novel six-slit-ring defected ground structure (DGS) is presented in this paper. The location of the slit can shift the resonant frequency without changing the overall size of the DGS and its adjustment range can reach 8.81 GHz. By cascading three identical six-slit-ring DGS unit cells, a microstrip low-pass filter (LPF) can be realized. Its 3dB cutoff frequency is 7.27 GHz. The in-band insertion loss is below 0.35 dB and the stop-band width with 20 dB attenuation is over 8.12 GHz. To improve the out-of-band rejection of the filter, shunt branches were added on both sides of the microstrip line. Its 3 dB cutoff frequency is 8.285 GHz. The insertion loss is less than 0.81dB in the pass-band. The stop-band rejection is better than -40 dB at 11.36-20 GHz and the size of the filter is only 28 mm by 11 mm. The simulation results show that the proposed novel six-slit-ring DGS microstrip LPF has the characteristics of compact size, flexible adjustment, flat pass-band, wide stop-band and high selectivity.
Microstrip stepped‐impedance hairpin resonator low‐pass filter with defected ground structure
In 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. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 405–408, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21364
A Novel Defected Ground Structure (DGS) Resonator for Bandpass Filters Applications
This paper introduces new compact bandpass filter using novel defected ground structure. Different coupling configurations and external coupling have been considered here. Different types of feeding arrangement show the different responses of the bandpass filter. Several second and third order bandpass filters have been designed. A second order bandpass filter is designed, fabricated and measured and their response matches well with the simulated results.