A fully reconfigurable 1 × 4 power divider with power division reconfiguration and size reduction based on series coupled cascaded transmission lines

Abstract

This work presents a 1X4 fully reconfigurable power divider with a wide range of power divisions and reduced size, designed for adaptive null forming and beam steering networks in RF front ends. The design is based on the impedance transformation of series-coupled cascaded transmission lines and a reconfigurable isolation network. The impedance of power-dividing arms is transformed by tuning the voltage-dependent equivalent capacitor, controlling insertion loss, and indirectly influencing the power division ratio. Four transmission states with sixteen different power levels are realized. This design approach is validated by fabricating a prototype with four output ports. The measured power division varies from 6.5 dB to 18 dB at the center frequency, and the return loss is greater than -32 dB. Output port isolation is greater than -30 dB, and the phase response at output ports only shows a difference of less than 2 degrees. The power at any output port can be reconfigured independently without affecting the system’s overall performance, achieved through a series-coupled transmission line, contributing to a reduction in size. A size reduction of 37 percent is attained in this design. The proposed power divider can provide a wide range of power levels at all output ports within a narrow band around the center frequency. Hence, the design is suitable for beam steering networks, pattern, and polarization reconfigurable antenna arrays. The design also has extension capability into N-way configurations.