A triple-notched band for UWB bandpass filter using embedded fold-slot structure

This paper proposes an ultra-wideband bandpass filter based on embedded fold-slot structure and slotted step impedance resonator (SSIR). The embedded fold-slot will be comprehensively described. The proposed filter has triple notched in the passband, resulting from the embedded fold-slot structure. The center frequencies and bandwidths of notched bands can be controlled by adjusting dimensions of the embedded fold-slot. The wider upper stopbands caused by slotted resonator characteristics have been also obtained. The simulated and experimental results show triple-notched band around 300 MHz, 350 MHz and 400 MHz, respectively. High stopband performances with better than 20 dB for a frequency range up to 18 GHz have also been obtained.