Planar lowpass filter with sharp roll-off using patch resonators on high impedance microstrip line

Planar lowpass filter with sharp roll-off rate by symmetrically loaded patch resonators is designed and demonstrated. Filter achieves a roll-off of 125 dB/GHz and a wide stopband with suppression level better than 23 dB from 2.72 GHz to 10 GHz. The filter is designed and developed using FR4 material with passband insertion loss of 0.5 dB.