Compact Hexagonal Shape Elliptical Low Pass Filter With Wide Stop Band

In this work a new hexagonal shape compact elliptical low pass filter (LPF) is introduced. To improve and extend the stop band, two additional transmission zeros are created by introducing three semi-circular slots in the ground plane. Insertion loss is <;0.85dB in the range of 0-1.5 GHz within the pass band and return loss is >18 dB in the entire pass band. Rejection band is extended up to >20 GHz with attenuation level better than -20dB. Obtained roll-off factor is 100 dB/GHz and group delay is 0.25 ns.