Abstract
A miniaturized balanced-to-unbalanced in-phase filtering power divider with wide upper stopband and wideband common-mode suppression is proposed. The in-phase feature is realized by the coupled/non-coupled lines. The stub with shunt-capacitor is used to realize the functions of filtering and miniaturization. The closed-form design equations are provided and discussed. To verify the design equations, one prototype with a center frequency of 1.0 GHz is designed and fabricated. The measured differential return loss is greater than 15 dB in the range of 0.82-1.22 GHz (39.2%). The upper stopband rejection is better than 20 dB from 1.41 to 3.57 GHz. Common-mode suppression is greater than 20 dB from 0 to 3.7 GHz. The measured results are in good agreement with electromagnetic simulations.