Tunable Balanced-to-Unbalanced In-Phase Power Divider: Theoretical Analysis and Design

This paper presents a tunable power divider (PD) which is balanced at the input port and unbalanced at the output ports. This tunable balanced-to-unbalanced (TBU) PD divides the power either equally or in specific ratio by varying capacitance in the circuit. The complete theoretical study is presented for this type of PD. The analysis is based on the impedance matching of all the ports and isolation requirements of the two unbalanced output ports. By changing the capacitance, different power dividing ratio (PDR) can be achieved. The theoretical results are obtained from the design equations of the proposed PD. The reflection coefficient of the unbalanced ports are better than 10 dB with fractional bandwidth of 21.5%. The isolation between the two output unbalanced ports is achieved better than 15 dB with fractional bandwidth of 23.5%. The proposed PD shows the in-phase characteristic between the two output signals