A wideband filtering power divider with improved out-of-band suppression

A wideband filtering power divider (WFPD) with improved out-of-band suppression is proposed in this letter. The WFPD integrates open-circuit stub loaded multimode resonators (OSLMRs) and stepped impedance resonators (SIRs) to achieve good in-band filtering performance, and introduces six out-of-band transmission zeros (TZs) to improve out-of-band suppression. A 3GHz WFPD was designed, fabricated and measured. The measured results shows that the out-of-band suppression level of the designed WFPD is greater than 22.5dB on the left side of the passband and greater than 40dB on the right side.