Design of a Low Cost Compact Elliptic Function LPF Using Open Circuited Stubs

Received: 31 December 2018 Accepted: 7 March 2019 A miniaturized microstrip lowpass filter with low insertion loss and wide attenuation band is presented in this study. The filter is designed using two open circuited stubs and six stepped impedance resonators aligned symmetrically. The insertion loss in the passband varies from -0.049 to -0.5 dB. The proposed lowpass filter has 3 dB cut-off frequency at 3 GHz and the stopband region is extended from 3.59 GHz to 14 GHz with an attenuation level of -15.5 dB. The roll-off factor for the proposed filter is 56 dB/GHz and the relative stopband suppression achieved is up to 130 %. Hence, the presented filter structure operating in S-band can be used in multiple applications like radar, WiMAX and other RF devices.