Compact UWB Bandpass Filter with a Notched Band

A compact wideband bandpass filter with a notched band is proposed, designed and implemented for ultra-wideband (UWB) system application on the basis of a modified stepped impedance resonator and asymmetrical interdigital feed-lines structures. The modified stepped impedance resonator can not only generate multiple-resonant peaks within the UWB passband but also easily realize a tight coupling with the feed-lines to realize a wide passband. The asymmetrical interdigital feed-lines can generate a notched band at 5.98 GHz with no significant influence on the passband performances. Both simulated and measured results are presented and they are in good agreement.