A dual-wideband filtering power divider using transmission zero-based band splitting with harmonic suppression

This paper presents a dual-wideband filtering power divider (FPD) based on a cascaded short-circuited stub loaded open-loop resonators using a transmission zero-based band splitting technique. A pair of resonators is interconnected through transmission lines to achieve wideband characteristics, while short-circuited stub loading enhances stopband performance. By incorporating an open-ended stub into each section of FPD, an additional transmission zero is introduced, enabling the realization of two distinct wide passbands from a single-wideband response. The proposed structure provides clear analytical insight into the relationship between transmission zero generation and dual-wideband formation. A prototype operating at 2 and 3.8 GHz is designed, fabricated, and experimentally validated. The measured results demonstrate fractional bandwidths (FBWs) of 50.3% and 28.1%, along with harmonic suppression up to 3.5 within a simple planar structure.