Simultaneous Amplitude-and Phase-Tunable Power Divider With Wide Tunable Ranges

With the rapid development of wireless technologies, the simultaneous and flexible control of amplitude and phase characteristics of the signals is highly demanded. However, none of the existing power dividers (PDs) can simultaneously achieve this tunability in a single circuit. In this article, a PD with simultaneously tunable power division ratio (PDR) and phase difference is presented for the first time. The proposed PD consists of two highly flexible arms, a matching network, and an isolation network. The arm is constructed by loading three varactor diodes on a quarter-wavelength 3-dB coupled line. A theoretical analysis is conducted to show that the input impedance and phase delay of this arm can be flexibly controlled by the capacitance of the varactor diodes. Subsequently, the PDR and phase difference between the two output ports can be tuned independently, maintaining good return loss and isolation. For demonstration purposes, a highly flexible PD operating at 2.4 GHz is designed, fabricated, and measured. A wide PDR range from $-$ 20 to 20 dB and a wide phase difference range from $-$ 180 $^{\circ}$ to 180 $^{\circ}$ are observed, with better than 10 dB return loss and 15 dB isolation.