Behnam Afzali - Department of Electrical Engineering, Faculty of Technical and Vocational No.۲, Kermanshah Branch, Technical and Vocational University (TVU), Kermanshah, Iran.
Farshid Yousefi Moghadam - Department of Electrical Engineering, Faculty of Technical and Vocational No.۲, Kermanshah Branch, Technical and Vocational University (TVU), Kermanshah, Iran.
Farshad Nadi - Department of Electrical Engineering, Faculty of Technical and Vocational No.۲, Kermanshah Branch, Technical and Vocational University (TVU), Kermanshah, Iran.
Rohallah Zallbeygi - Department of Electrical Engineering, Faculty of Technical and Vocational No.۲, Kermanshah Branch, Technical and Vocational University (TVU), Kermanshah, Iran.

In this paper, a novel compact microstrip Low-Pass Filter (LPF) with sharp roll-off and ultra-wide stopband with high suppression level is presented. In the proposed filter, square-shaped resonators are used. The cut-off frequency at ۳dB is ۱.۸۸GHz. The maximum insertion loss of this filter is less than ۰.۱dB and the return loss is also less than ۱۶dB in the passband. In the proposed structure, the stopband extends from ۲.۰۷ to ۲۹.۵ GHz at ۲۴dB level of suppression and is considered as an ultra-wide stopband. There is a significant relationship between simulation and fabrication results, which have justified the functionality of the proposed LFP, respectively.

Cut-off Frequency, Filter, LC Equivalent, Low-Pass, microstrip, Resonator, Sharp Roll-Off, Square-Shaped, Transformation function, Ultra-Wide Stopband