Compact microstrip Wideband Band Stop Filter with folded stubs to increase coupling

This work presents a new type of wide band stop filter (BSF). The proposed filter topology consists of folded stubs, which controls band stop range. The filter characteristics can be easily controlled by the length of stubs and folded stubs can control coupling between two stubs. The proposed filter design has cut-off frequency of 2.3 GHz. Stopband rejection depth and bandwidth can be controlled by stubs width and spacing between stubs. Three zeros are present in stopband region. This proposed filter has 2.3 - 4.3 GHz band width with 20dB rejection. Sharp cut off rate is achieved 28.3dB per GHz frequency. The compact design structure has size of 15.48mm×29.6mm (0.16λg×0.31λg ) with port length.