Design of A High Attenuation a Microstrip Wide-Stopband Bandstop Filter Applied in Ku and K Bands

The compact microstrip bandstop filters with high attenuation and wide stopband have been developed. In order to realize the bandstop filter with broad stopband and great attenuation within the stopband, the coupled lines with single-ended ground have been adopted at both input and output ports. Moreover, for a greater fractional bandwidth, a higher impedance ratio Ze/Zo of the adopted coupled lines is required. The bandstop filter, with the attenuation of 40 dB and a fractional bandwidth of 60%, has been developed for applied in Ku and K bands to verify the proposed method.