Compact lowpass filter with ultra-wide stopband using novel spiral compact microstrip resonant cell

Abstract

In this paper a novel spiral compact microstrip resonant cell (NSCMRC) to design a low pass filter with wide stopband is presented. The slow-wave effect and scattering and radiation parameters are depicted. The designed lowpass filter is implemented by cascading three cells with different dimensions that shows the advantages of low insertion loss less than 0.03dB and wide stopband from 4GHZ up to 50GHZ with suppression level better than -13.4dB and compact size. Finally, the proposed lowpass filter is fabricated and a good agreement between simulated and the measured results are demonstrated.