Microstrip Low-pass Filter with Sharp Roll off and Wide Stop-band Using Multiple Cascaded Modified Radial Stubs Resonators

This paper presents a novel microstrip low-pass filter with good performance. A complete detailed theoretical analysis for the proposed filter is given using equivalent circuit models. The proposed filter applying multiple cascaded modified radial stubs resonators provides a sharp cut off frequency response that has a 185 dB/GHz roll off rate. Also, U-shaped attenuators provide a wide stop-band about 14fc with more than -20 dB rejection. The filter has an insertion loss less than 0.027 dB from dc to 1.31 GHz. The experimental results are in fair agreement with the simulated results.