A novel microstrip low pass filter based on ring topology

Abstract

This paper describes the design of a new configuration of a low pass filter (LPF). This filter structure is based on a ring topology. The proposed LPF is miniature and low cost because it is mounted on FR4 substrate. The validation of this circuit into simulation was based on many optimization methods integrated in ADS "Advanced Design System" and some tuning methods. At the end, the fabrication and the test of the final circuit permits to have a good agreement between simulation and measurement results reaching a low pass behavior. The proposed filter has an area of 25x25 mm2, with a cutoff frequency of 2GHz and good performances in term of insertion losses, which are around -0.127 dB in the whole bandwidth and a high stopband.