Abstract: A novel low-pass filter using defected microstrip structure (DMS) is proposed in this paper. The frequency characteristics of the DMS are simulated with three-dimension electromagnetic field analysis software. Its equivalent circuit and equivalent parameters are extracted with microwave circuit analysis software. Then a novel low-pass filter using DMS is designed and fabricated. The measured 3dB cutoff frequency fc is 3.4GHz with 0.3dB ripple level. The rejection bandwidth of the insertion loss less then ?15dB is 13GHz. The experimental results show good agreement with simulation, validating effectiveness of the equivalent circuit and the realization of the DMS LPF.

Key words: defected microstrip structure (DMS), equivalent circuit, low-pass filter