A New Filtering Out-of-Phase Power Divider With Unequal Power Distribution Using Modified Branch-Line Structure

This letter proposes a new filtering power divider with out-of-phase characteristic and unequal power division ratio. Stemming from the traditional branch-line prototype, a modified structure is proposed to realize bandpass response with unequal power division and out-of-phase behavior. It is constructed in a three-stage branch-line structure, loaded with short-ended stubs, responsible for out-of-band suppressions. In addition, two anti-phase signals at output ports could be well isolated by a grounded chip resistor. For validation, a practical power divider circuit operating at 2.0 GHz with a 3-dB fractional bandwidth of 27% and a power division ratio of 4:1 are designed, fabricated, and measured. Results show that the presented power divider exhibits good filtering response, satisfactory out-of-band rejection, anti-phase difference, and desired unequal power distribution.