Tunable Balanced Power Dividers: An Overview of Recently Developed Balanced Power Dividers and Couplers with Fixed and Tunable Functions

An Overview of recently developed balanced power dividers and couplers with fixed and tunable functions is presented. Compared with single-ended circuits, balanced circuits can provide high immunity to environmental noise and broadband common-mode rejection capability. Various balanced passive circuits, such as filters antennas, power dividers, and couplers have been extensively studied. Power dividers and couplers are widely used in microwave integrated circuits, such as antenna feeding networks, balanced mixers, and amplifiers. Balanced couplers are used in double-balanced mixers and balanced frequency doublers to achieve higher efficiency and lower loss. Power dividers and couplers with tunable power dividing ratios have been used to design polarization reconfigurable and pattern-reconfigurable antennas d Butler matrixes with improved sidelobe levels.