volume | PIER Journals

Abstract

Compact size microstrip low-pass filters with sharp cutoff characteristics, narrow passband, low insertion loss, high attenuation in stopband, and low cost are highly required in modern wireless communication systems. They are used to suppress the unwanted harmonics and noise caused by Radio Frequency (RF) front ends. In this paper, a new design for compact microstrip LPF is proposed. It is based on utilization of Stepped Impedance Resonators (SIR), Defected Microstrip Structure (DMS), Dumbbell-shaped Defected Ground Structure (DB-DGS), and surface mount capacitor. The filter is realized on an F4B-2 substrate with ε_r=2.65, thickness h=0.5 mm and loss tangent δ=0.0013. The design is carried out using CST-Microwave Studio software. The equivalent circuit of the filter is analyzed and presented using ADS2006A software. The filter exhibits sharp cutoff frequency f_c=1.7654 GHz, wide stopband from 1.7654 GHz to 7 GHz with |S₂₁| less than -10 dB, insertion loss less than 0.15 dB in passband, and reduced size compared to the traditional LPF.

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Dr. Alaa Mohammed Abada

Professor Amr H. Hussein

Dr. Mohmoud Ahmed Attia Ali