Abstract
In this paper, a low-pass filter (LPF) microstrip generalized Chebyshev type defected ground with a high suppression stopband was proposed. The resonators of the suggested filter were implemented using a T-shape microstrip. The filter resonators consist of three main parts. A part of the resonators was used to improve the rejection of the filter in the stopping region, a second part was used to increase the selectivity of the filter, and the last part was used to balance between the two regions. The microstrip LPF filter is designed on a Roger RT/Duroid 5880 substrate with εr=2.2, a thickness of 0.381 mm. 11th order generalized Chebyshev LPF was simulated using HFSS software. The simulation results were as follows: 2 GHz for the cut-off frequency, insertion loss of 0.55 dB at about 20 dB return loss, and a wide range of stopband suppression below the level of 28 dB from frequency 3.4 GHz to 20 GHz. The LPF selectivity was approximately 37.5 dB/GHz and a small and compact size filter with 0.014λ2g was introduced. The filter matches the specifications required for fifth-generation filters in wireless communications systems.
